WO2025152099A1

WO2025152099A1 - Enhancement for initial access of type-c ambient-iot device

Info

Publication number: WO2025152099A1
Application number: PCT/CN2024/072947
Authority: WO
Inventors: Luanxia YANG; Piyush Gupta
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2024-01-18
Filing date: 2024-01-18
Publication date: 2025-07-24
Anticipated expiration: 2026-07-18

Abstract

The apparatus may be an ambient IoT device configured to obtain a first indication of a plurality of resources for a preamble transmission from the ambient IoT device and a corresponding plurality of downlink signal strength ranges, obtain a second indication for a set of power ramp steps associated with the plurality of resources, and perform a random access procedure associated with a network device based on the first indication and the second indication. The apparatus may be a network device configured to output a first indication of a plurality of resources for a preamble transmission and a corresponding plurality of downlink signal strength ranges, output a second indication for a set of power ramp steps associated with the plurality of resources, and receive at least one random access message based on the first indication and the second indication.

Description

ENHANCEMENT FOR INITIAL ACCESS OF TYPE-C AMBIENT-IOT DEVICE

TECHNICAL FIELD

The present disclosure relates generally to communication systems, and more particularly, to wireless communication associated with an active ambient internet-of-tings (IoT) device.

INTRODUCTION

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR) . 5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT) ) , and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB) , massive machine type communications (mMTC) , and ultra-reliable low latency communications (URLLC) . Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There exists a need for further improvements in 5G NR technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

BRIEF SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects. This summary neither identifies key or critical elements of all aspects nor delineates the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be an active backscatter device (e.g., an ambient IoT device capable of storing energy and initiating transmissions such as a type C ambient IoT device) configured to obtain a first indication of a plurality of resources for a preamble transmission from the active backscatter device and a corresponding plurality of downlink signal strength ranges, obtain a second indication for a set of power ramp steps associated with the plurality of resources, and perform a random access procedure associated with a network device based on the first indication and the second indication.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a network device (e.g., a base station) configured to output a first indication of a plurality of resources for a preamble transmission from at least one active backscatter device and a corresponding plurality of downlink signal strength ranges, output a second indication for a set of power ramp steps associated with the plurality of resources, and receive at least one random access message associated with the at least one active backscatter device based on the first indication and the second indication.

To the accomplishment of the foregoing and related ends, the one or more aspects may include the features hereinafter fully described and particularly pointed out in the claims. The following description and the drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network.

FIG. 2A is a diagram illustrating an example of a first frame, in accordance with various aspects of the present disclosure.

FIG. 2B is a diagram illustrating an example of downlink (DL) channels within a subframe, in accordance with various aspects of the present disclosure.

FIG. 2C is a diagram illustrating an example of a second frame, in accordance with various aspects of the present disclosure.

FIG. 2D is a diagram illustrating an example of uplink (UL) channels within a subframe, in accordance with various aspects of the present disclosure.

FIG. 3 is a diagram illustrating an example of a base station and user equipment (UE) in an access network.

FIG. 4 illustrates a diagram of an RFID tag that receives an energy transfer signal from an RFID reader.

FIG. 5 is a call flow diagram illustrating an inventory method associated with backscatter devices (e.g., ambient IoT devices) in accordance with some aspects of the disclosure.

FIG. 6 is a call flow diagram illustrating a method of random access for a wireless device in accordance with some aspects of the disclosure.

FIG. 7 is a set of diagrams illustrating a plurality of resources that may be associated with a random access (or initial access) procedure associated with a measured and/or detected DL signal strength in accordance with some aspects of the disclosure.

FIG. 8 is a set of diagrams illustrating a first set of power ramp and repetition patterns that may be used for an initial preamble transmission and retransmissions in association with a random access (or initial access) procedure for an active ambient IoT device in accordance with some aspects of the disclosure.

FIG. 9 is a set of diagrams illustrating a second set of power ramp and repetition patterns that may be used for an initial preamble transmission and retransmissions in association with a random access (or initial access) procedure for an active ambient IoT device in accordance with some aspects of the disclosure.

FIG. 10 is a diagram illustrating a power ramp and repetition pattern that may be used for an initial preamble transmission and retransmissions in association with a random access (or initial access) procedure for an active ambient IoT device in accordance with some aspects of the disclosure.

FIG. 11 is a call flow diagram illustrating a method for an initial access (or random access) procedure associated with an active ambient IoT device (e.g., a type C ambient IoT device) in accordance with some aspects of the disclosure.

FIG. 12 is a flowchart of a method of wireless communication.

FIG. 13 is a flowchart of a method of wireless communication.

FIG. 14 is a flowchart of a method of wireless communication.

FIG. 15 is a flowchart of a method of wireless communication.

FIG. 16 is a diagram illustrating an example of a hardware implementation for an apparatus.

FIG. 17 is a diagram illustrating an example of a hardware implementation for a network entity.

FIG. 18 is a diagram illustrating an example of a hardware implementation for an apparatus.

DETAILED DESCRIPTION

Ambient IoT devices may be employed in some aspects of wireless communication. An ambient IoT device, in some aspects, may include passive elements capable of backscattering an impinging signal, energy harvesting components capable of receiving and/or collecting energy from one or more sources (thermal energy, transmitted (radio frequency) energy, etc. ) , energy storage components capable of storing energy, and active components (e.g., a transceiver) capable of transmitting signals to other network elements. Ambient IoT devices may be categorized based on their components and/or capabilities. For example, a first class of ambient IoT device (e.g., a passive ambient IoT device, a type A ambient IoT device, or Device A) may be associated with devices lacking energy storage and an independent signal generation capacity. A second class of ambient IoT device (e.g., a semi-passive ambient IoT device, a type B ambient IoT device, or Device B) may be associated with devices having energy storage (and possibly an amplification capability based on the stored energy) and lacking an independent signal generation capacity. A third class of ambient IoT device (e.g., an active ambient IoT device, a type C ambient IoT device, or Device C) may be associated with devices having energy storage and an independent signal generation capacity (e.g., may have active radio-frequency (RF) components for signal generation and/or transmission) . Within a class of ambient IoT device, different ambient IoT devices may have different capacities (e.g., may be able to store different amounts of energy or power, or may have different maximum amplifications) .

Some aspects of wireless communication configured for interaction with passive ambient IoT devices (e.g., devices without independent signal generation capabilities) may be non-optimal for active ambient IoT devices. Accordingly, various aspects relate generally to additional signaling to improve the reliability of random access procedures for ambient IoT (or A-IoT) devices. In particular, an indication of a transmission power, an associated signal strength, and repetition may improve random access performance. Some aspects more specifically relate to a configuration for transmission and/or retransmission of an initial access message. In some examples, an active backscatter device (e.g., an ambient IoT device capable of storing energy and independently generating signals such as a type C ambient IoT device) may be configured to obtain a first indication of a plurality of resources for a preamble transmission from the active backscatter device and a corresponding plurality of downlink signal strength ranges, obtain a second indication for a set of power ramp steps associated with the plurality of resources, and perform a random access procedure associated with a network device based on the first indication and the second indication. In some examples, a network device (e.g., a base station) may be configured to output a first indication of a plurality of resources for a preamble transmission from at least one active backscatter device and a corresponding plurality of downlink signal strength ranges, output a second indication for a set of power ramp steps associated with the plurality of resources, and receive at least one random access message associated with the at least one active backscatter device based on the first indication and the second indication.

Particular aspects of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. In some examples, by using the initial access procedure for the active ambient IoT device, the described techniques can be used to reduce a latency associated with initial access and avoid collisions based on the large number of ambient IoT devices.

The detailed description set forth below in connection with the drawings describes various configurations and does not represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems are presented with reference to various apparatus and methods. These apparatus and methods are described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. When multiple processors are implemented, the multiple processors may perform the functions individually or in combination. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs) , central processing units (CPUs) , application processors, digital signal processors (DSPs) , reduced instruction set computing (RISC) processors, systems on a chip (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise, shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, or any combination thereof.

Accordingly, in one or more example aspects, implementations, and/or use cases, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer. By way of example, such computer-readable media can include a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

While aspects, implementations, and/or use cases are described in this application by illustration to some examples, additional or different aspects, implementations and/or use cases may come about in many different arrangements and scenarios. Aspects, implementations, and/or use cases described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, aspects, implementations, and/or use cases may come about via integrated chip implementations and other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, artificial intelligence (AI) -enabled devices, etc. ) . While some examples may or may not be specifically directed to use cases or applications, a wide assortment of applicability of described examples may occur. Aspects, implementations, and/or use cases may range a spectrum from chip-level or modular components to non-modular, non-chip-level implementations and further to aggregate, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more techniques herein. In some practical settings, devices incorporating described aspects and features may also include additional components and features for implementation and practice of claimed and described aspect. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes (e.g., hardware components including antenna, RF-chains, power amplifiers, modulators, buffer, processor (s) , interleaver, adders/summers, etc. ) . Techniques described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, aggregated or disaggregated components, end-user devices, etc. of varying sizes, shapes, and constitution.

Deployment of communication systems, such as 5G NR systems, may be arranged in multiple manners with various components or constituent parts. In a 5G NR system, or network, a network node, a network entity, a mobility element of a network, a radio access network (RAN) node, a core network node, a network element, or a network equipment, such as a base station (BS) , or one or more units (or one or more components) performing base station functionality, may be implemented in an aggregated or disaggregated architecture. For example, a BS (such as a Node B (NB) , evolved NB (eNB) , NR BS, 5G NB, access point (AP) , a transmission reception point (TRP) , or a cell, etc. ) may be implemented as an aggregated base station (also known as a standalone BS or a monolithic BS) or a disaggregated base station.

An aggregated base station may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. A disaggregated base station may be configured to utilize a protocol stack that is physically or logically distributed among two or more units (such as one or more central or centralized units (CUs) , one or more distributed units (DUs) , or one or more radio units (RUs) ) . In some aspects, a CU may be implemented within a RAN node, and one or more DUs may be co-located with the CU, or alternatively, may be geographically or virtually distributed throughout one or multiple other RAN nodes. The DUs may be implemented to communicate with one or more RUs. Each of the CU, DU and RU can be implemented as virtual units, i.e., a virtual central unit (VCU) , a virtual distributed unit (VDU) , or a virtual radio unit (VRU) .

Base station operation or network design may consider aggregation characteristics of base station functionality. For example, disaggregated base stations may be utilized in an integrated access backhaul (IAB) network, an open radio access network (O-RAN (such as the network configuration sponsored by the O-RAN Alliance) ) , or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN) ) . Disaggregation may include distributing functionality across two or more units at various physical locations, as well as distributing functionality for at least one unit virtually, which can enable flexibility in network design. The various units of the disaggregated base station, or disaggregated RAN architecture, can be configured for wired or wireless communication with at least one other unit.

FIG. 1 is a diagram 100 illustrating an example of a wireless communications system and an access network. The illustrated wireless communications system includes a disaggregated base station architecture. The disaggregated base station architecture may include one or more CUs 110 that can communicate directly with a core network 120 via a backhaul link, or indirectly with the core network 120 through one or more disaggregated base station units (such as a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC) 125 via an E2 link, or a Non-Real Time (Non-RT) RIC 115 associated with a Service Management and Orchestration (SMO) Framework 105, or both) . A CU 110 may communicate with one or more DUs 130 via respective midhaul links, such as an F1 interface. The DUs 130 may communicate with one or more RUs 140 via respective fronthaul links. The RUs 140 may communicate with respective UEs 104 via one or more radio frequency (RF) access links. In some implementations, the UE 104 may be simultaneously served by multiple RUs 140.

Each of the units, i.e., the CUs 110, the DUs 130, the RUs 140, as well as the Near-RT RICs 125, the Non-RT RICs 115, and the SMO Framework 105, may include one or more interfaces or be coupled to one or more interfaces configured to receive or to transmit signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units, or an associated processor or controller providing instructions to the communication interfaces of the units, can be configured to communicate with one or more of the other units via the transmission medium. For example, the units can include a wired interface configured to receive or to transmit signals over a wired transmission medium to one or more of the other units. Additionally, the units can include a wireless interface, which may include a receiver, a transmitter, or a transceiver (such as an RF transceiver) , configured to receive or to transmit signals, or both, over a wireless transmission medium to one or more of the other units.

In some aspects, the CU 110 may host one or more higher layer control functions. Such control functions can include radio resource control (RRC) , packet data convergence protocol (PDCP) , service data adaptation protocol (SDAP) , or the like. Each control function can be implemented with an interface configured to communicate signals with other control functions hosted by the CU 110. The CU 110 may be configured to handle user plane functionality (i.e., Central Unit –User Plane (CU-UP) ) , control plane functionality (i.e., Central Unit –Control Plane (CU-CP) ) , or a combination thereof. In some implementations, the CU 110 can be logically split into one or more CU-UP units and one or more CU-CP units. The CU-UP unit can communicate bidirectionally with the CU-CP unit via an interface, such as an E1 interface when implemented in an O-RAN configuration. The CU 110 can be implemented to communicate with the DU 130, as necessary, for network control and signaling.

The DU 130 may correspond to a logical unit that includes one or more base station functions to control the operation of one or more RUs 140. In some aspects, the DU 130 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation, demodulation, or the like) depending, at least in part, on a functional split, such as those defined by 3GPP. In some aspects, the DU 130 may further host one or more low PHY layers. Each layer (or module) can be implemented with an interface configured to communicate signals with other layers (and modules) hosted by the DU 130, or with the control functions hosted by the CU 110.

Lower-layer functionality can be implemented by one or more RUs 140. In some deployments, an RU 140, controlled by a DU 130, may correspond to a logical node that hosts RF processing functions, or low-PHY layer functions (such as performing fast Fourier transform (FFT) , inverse FFT (iFFT) , digital beamforming, physical random access channel (PRACH) extraction and filtering, or the like) , or both, based at least in part on the functional split, such as a lower layer functional split. In such an architecture, the RU (s) 140 can be implemented to handle over the air (OTA) communication with one or more UEs 104. In some implementations, real-time and non-real-time aspects of control and user plane communication with the RU (s) 140 can be controlled by the corresponding DU 130. In some scenarios, this configuration can enable the DU (s) 130 and the CU 110 to be implemented in a cloud-based RAN architecture, such as a vRAN architecture.

The SMO Framework 105 may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non-virtualized network elements, the SMO Framework 105 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements that may be managed via an operations and maintenance interface (such as an O1 interface) . For virtualized network elements, the SMO Framework 105 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 190) to perform network element life cycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an O2 interface) . Such virtualized network elements can include, but are not limited to, CUs 110, DUs 130, RUs 140 and Near-RT RICs 125. In some implementations, the SMO Framework 105 can communicate with a hardware aspect of a 4G RAN, such as an open eNB (O-eNB) 111, via an O1 interface. Additionally, in some implementations, the SMO Framework 105 can communicate directly with one or more RUs 140 via an O1 interface. The SMO Framework 105 also may include a Non-RT RIC 115 configured to support functionality of the SMO Framework 105.

The Non-RT RIC 115 may be configured to include a logical function that enables non-real-time control and optimization of RAN elements and resources, artificial intelligence (AI) /machine learning (ML) (AI/ML) workflows including model training and updates, or policy-based guidance of applications/features in the Near-RT RIC 125. The Non-RT RIC 115 may be coupled to or communicate with (such as via an A1 interface) the Near-RT RIC 125. The Near-RT RIC 125 may be configured to include a logical function that enables near-real-time control and optimization of RAN elements and resources via data collection and actions over an interface (such as via an E2 interface) connecting one or more CUs 110, one or more DUs 130, or both, as well as an O-eNB, with the Near-RT RIC 125.

In some implementations, to generate AI/ML models to be deployed in the Near-RT RIC 125, the Non-RT RIC 115 may receive parameters or external enrichment information from external servers. Such information may be utilized by the Near-RT RIC 125 and may be received at the SMO Framework 105 or the Non-RT RIC 115 from non-network data sources or from network functions. In some examples, the Non-RT RIC 115 or the Near-RT RIC 125 may be configured to tune RAN behavior or performance. For example, the Non-RT RIC 115 may monitor long-term trends and patterns for performance and employ AI/ML models to perform corrective actions through the SMO Framework 105 (such as reconfiguration via O1) or via creation of RAN management policies (such as A1 policies) .

At least one of the CU 110, the DU 130, and the RU 140 may be referred to as a base station 102. Accordingly, a base station 102 may include one or more of the CU 110, the DU 130, and the RU 140 (each component indicated with dotted lines to signify that each component may or may not be included in the base station 102) . The base station 102 provides an access point to the core network 120 for a UE 104. The base station 102 may include macrocells (high power cellular base station) and/or small cells (low power cellular base station) . The small cells include femtocells, picocells, and microcells. A network that includes both small cell and macrocells may be known as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs) , which may provide service to a restricted group known as a closed subscriber group (CSG) . The communication links between the RUs 140 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to an RU 140 and/or downlink (DL) (also referred to as forward link) transmissions from an RU 140 to a UE 104. The communication links may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The base station 102 /UEs 104 may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL than for UL) . The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell) .

Certain UEs 104 may communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 may use the DL/UL wireless wide area network (WWAN) spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) . D2D communication may be through a variety of wireless D2D communications systems, such as for example, Bluetooth^TM (Bluetooth is a trademark of the Bluetooth Special Interest Group (SIG) ) , Wi-Fi^TM (Wi-Fi is a trademark of the Wi-Fi Alliance) based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi AP 150 in communication with UEs 104 (also referred to as Wi-Fi stations (STAs) ) via communication link 154, e.g., in a 5 GHz unlicensed frequency spectrum or the like. When communicating in an unlicensed frequency spectrum, the UEs 104 /AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

The electromagnetic spectrum is often subdivided, based on frequency/wavelength, into various classes, bands, channels, etc. In 5G NR, two initial operating bands have been identified as frequency range designations FR1 (410 MHz –7.125 GHz) and FR2 (24.25 GHz –52.6 GHz) . Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as a “sub-6 GHz” band in various documents and articles. A similar nomenclature issue sometimes occurs with regard to FR2, which is often referred to (interchangeably) as a “millimeter wave” band in documents and articles, despite being different from the extremely high frequency (EHF) band (30 GHz –300 GHz) which is identified by the International Telecommunications Union (ITU) as a “millimeter wave” band.

The frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Recent 5G NR studies have identified an operating band for these mid-band frequencies as frequency range designation FR3 (7.125 GHz –24.25 GHz) . Frequency bands falling within FR3 may inherit FR1 characteristics and/or FR2 characteristics, and thus may effectively extend features of FR1 and/or FR2 into mid-band frequencies. In addition, higher frequency bands are currently being explored to extend 5G NR operation beyond 52.6 GHz. For example, three higher operating bands have been identified as frequency range designations FR2-2 (52.6 GHz –71 GHz) , FR4 (71 GHz –114.25 GHz) , and FR5 (114.25 GHz –300 GHz) . Each of these higher frequency bands falls within the EHF band.

With the above aspects in mind, unless specifically stated otherwise, the term “sub-6 GHz” or the like if used herein may broadly represent frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies. Further, unless specifically stated otherwise, the term “millimeter wave” or the like if used herein may broadly represent frequencies that may include mid-band frequencies, may be within FR2, FR4, FR2-2, and/or FR5, or may be within the EHF band.

The base station 102 and the UE 104 may each include a plurality of antennas, such as antenna elements, antenna panels, and/or antenna arrays to facilitate beamforming. The base station 102 may transmit a beamformed signal 182 to the UE 104 in one or more transmit directions. The UE 104 may receive the beamformed signal from the base station 102 in one or more receive directions. The UE 104 may also transmit a beamformed signal 184 to the base station 102 in one or more transmit directions. The base station 102 may receive the beamformed signal from the UE 104 in one or more receive directions. The base station 102 /UE 104 may perform beam training to determine the best receive and transmit directions for each of the base station 102 /UE 104. The transmit and receive directions for the base station 102 may or may not be the same. The transmit and receive directions for the UE 104 may or may not be the same.

The base station 102 may include and/or be referred to as a gNB, Node B, eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a TRP, network node, network entity, network equipment, or some other suitable terminology. The base station 102 can be implemented as an integrated access and backhaul (IAB) node, a relay node, a sidelink node, an aggregated (monolithic) base station with a baseband unit (BBU) (including a CU and a DU) and an RU, or as a disaggregated base station including one or more of a CU, a DU, and/or an RU. The set of base stations, which may include disaggregated base stations and/or aggregated base stations, may be referred to as next generation (NG) RAN (NG-RAN) .

The core network 120 may include an Access and Mobility Management Function (AMF) 161, a Session Management Function (SMF) 162, a User Plane Function (UPF) 163, a Unified Data Management (UDM) 164, one or more location servers 168, and other functional entities. The AMF 161 is the control node that processes the signaling between the UEs 104 and the core network 120. The AMF 161 supports registration management, connection management, mobility management, and other functions. The SMF 162 supports session management and other functions. The UPF 163 supports packet routing, packet forwarding, and other functions. The UDM 164 supports the generation of authentication and key agreement (AKA) credentials, user identification handling, access authorization, and subscription management. The one or more location servers 168 are illustrated as including a Gateway Mobile Location Center (GMLC) 165 and a Location Management Function (LMF) 166. However, generally, the one or more location servers 168 may include one or more location/positioning servers, which may include one or more of the GMLC 165, the LMF 166, a position determination entity (PDE) , a serving mobile location center (SMLC) , a mobile positioning center (MPC) , or the like. The GMLC 165 and the LMF 166 support UE location services. The GMLC 165 provides an interface for clients/applications (e.g., emergency services) for accessing UE positioning information. The LMF 166 receives measurements and assistance information from the NG-RAN and the UE 104 via the AMF 161 to compute the position of the UE 104. The NG-RAN may utilize one or more positioning methods in order to determine the position of the UE 104. Positioning the UE 104 may involve signal measurements, a position estimate, and an optional velocity computation based on the measurements. The signal measurements may be made by the UE 104 and/or the base station 102 serving the UE 104. The signals measured may be based on one or more of a satellite positioning system (SPS) 170 (e.g., one or more of a Global Navigation Satellite System (GNSS) , global position system (GPS) , non-terrestrial network (NTN) , or other satellite position/location system) , LTE signals, wireless local area network (WLAN) signals, Bluetooth signals, a terrestrial beacon system (TBS) , sensor-based information (e.g., barometric pressure sensor, motion sensor) , NR enhanced cell ID (NR E-CID) methods, NR signals (e.g., multi-round trip time (Multi-RTT) , DL angle-of-departure (DL-AoD) , DL time difference of arrival (DL-TDOA) , UL time difference of arrival (UL-TDOA) , and UL angle-of-arrival (UL-AoA) positioning) , and/or other systems/signals/sensors.

Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA) , a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player) , a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs 104 may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc. ) . The UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology. In some scenarios, the term UE may also apply to one or more companion devices such as in a device constellation arrangement. One or more of these devices may collectively access the network and/or individually access the network.

Referring again to FIG. 1, in certain aspects, the UE 104 may have an active ambient IoT device initial access component 198 that may be configured to obtain a first indication of a plurality of resources for a preamble transmission from the active backscatter device and a corresponding plurality of downlink signal strength ranges, obtain a second indication for a set of power ramp steps associated with the plurality of resources, and perform a random access procedure associated with a network device based on the first indication and the second indication. In certain aspects, the base station 102 may have an active ambient IoT device initial access configuration component 199 that may be configured to output a first indication of a plurality of resources for a preamble transmission from at least one active backscatter device and a corresponding plurality of downlink signal strength ranges, output a second indication for a set of power ramp steps associated with the plurality of resources, and receive at least one random access message associated with the at least one active backscatter device based on the first indication and the second indication. Although the following description may be focused on 5G NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

FIG. 2A is a diagram 200 illustrating an example of a first subframe within a 5G NR frame structure. FIG. 2B is a diagram 230 illustrating an example of DL channels within a 5G NR subframe. FIG. 2C is a diagram 250 illustrating an example of a second subframe within a 5G NR frame structure. FIG. 2D is a diagram 280 illustrating an example of UL channels within a 5G NR subframe. The 5G NR frame structure may be frequency division duplexed (FDD) in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for either DL or UL, or may be time division duplexed (TDD) in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for both DL and UL. In the examples provided by FIGs. 2A, 2C, the 5G NR frame structure is assumed to be TDD, with subframe 4 being configured with slot format 28 (with mostly DL) , where D is DL, U is UL, and F is flexible for use between DL/UL, and subframe 3 being configured with slot format 1 (with all UL) . While subframes 3, 4 are shown with slot formats 1, 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. Slot formats 0, 1 are all DL, UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. UEs are configured with the slot format (dynamically through DL control information (DCI) , or semi-statically/statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI) . Note that the description infra applies also to a 5G NR frame structure that is TDD.

FIGs. 2A-2D illustrate a frame structure, and the aspects of the present disclosure may be applicable to other wireless communication technologies, which may have a different frame structure and/or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms) . Each subframe may include one or more time slots. Subframes may also include mini-slots, which may include 7, 4, or 2 symbols. Each slot may include 14 or 12 symbols, depending on whether the cyclic prefix (CP) is normal or extended. For normal CP, each slot may include 14 symbols, and for extended CP, each slot may include 12 symbols. The symbols on DL may be CP orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbols. The symbols on UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (for power limited scenarios; limited to a single stream transmission) . The number of slots within a subframe is based on the CP and the numerology. The numerology defines the subcarrier spacing (SCS) (see Table 1) . The symbol length/duration may scale with 1/SCS.

Table 1: Numerology, SCS, and CP

For normal CP (14 symbols/slot) , different numerologies μ 0 to 4 allow for 1, 2, 4, 8, and 16 slots, respectively, per subframe. For extended CP, the numerology 2 allows for 4 slots per subframe. Accordingly, for normal CP and numerology μ, there are 14 symbols/slot and 2^μ slots/subframe. The subcarrier spacing may be equal to 2^μ*15 kHz, where μ is the numerology 0 to 4. As such, the numerology μ=0 has a subcarrier spacing of 15 kHz and the numerology μ=4 has a subcarrier spacing of 240 kHz. The symbol length/duration is inversely related to the subcarrier spacing. FIGs. 2A-2D provide an example of normal CP with 14 symbols per slot and numerology μ=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs. Within a set of frames, there may be one or more different bandwidth parts (BWPs) (see FIG. 2B) that are frequency division multiplexed. Each BWP may have a particular numerology and CP (normal or extended) .

A resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs) ) that extends 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs) . The number of bits carried by each RE depends on the modulation scheme.

As illustrated in FIG. 2A, some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include demodulation RS (DM-RS) (indicated as R for one particular configuration, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RS) for channel estimation at the UE. The RS may also include beam measurement RS (BRS) , beam refinement RS (BRRS) , and phase tracking RS (PT-RS) .

FIG. 2B illustrates an example of various DL channels within a subframe of a frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) (e.g., 1, 2, 4, 8, or 16 CCEs) , each CCE including six RE groups (REGs) , each REG including 12 consecutive REs in an OFDM symbol of an RB. A PDCCH within one BWP may be referred to as a control resource set (CORESET) . A UE is configured to monitor PDCCH candidates in a PDCCH search space (e.g., common search space, UE-specific search space) during PDCCH monitoring occasions on the CORESET, where the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs may be located at greater and/or lower frequencies across the channel bandwidth. A primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE 104 to determine subframe/symbol timing and a physical layer identity. A secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI) . Based on the PCI, the UE can determine the locations of the DM-RS. The physical broadcast channel (PBCH) , which carries a master information block (MIB) , may be logically grouped with the PSS and SSS to form a synchronization signal (SS) /PBCH block (also referred to as SS block (SSB) ) . The MIB provides a number of RBs in the system bandwidth and a system frame number (SFN) . The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs) , and paging messages.

As illustrated in FIG. 2C, some of the REs carry DM-RS (indicated as R for one particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE may transmit DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH) . The PUSCH DM-RS may be transmitted in the first one or two symbols of the PUSCH. The PUCCH DM-RS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used. The UE may transmit sounding reference signals (SRS) . The SRS may be transmitted in the last symbol of a subframe. The SRS may have a comb structure, and a UE may transmit SRS on one of the combs. The SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

FIG. 2D illustrates an example of various UL channels within a subframe of a frame. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI) , such as scheduling requests, a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a rank indicator (RI) , and hybrid automatic repeat request (HARQ) acknowledgment (ACK) (HARQ-ACK) feedback (i.e., one or more HARQ ACK bits indicating one or more ACK and/or negative ACK (NACK) ) . The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , and/or UCI.

FIG. 3 is a block diagram of a base station 310 in communication with a UE 350 in an access network. In the DL, Internet protocol (IP) packets may be provided to a controller/processor 375. The controller/processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller/processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIBs) , RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release) , inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression /decompression, security (ciphering, deciphering, integrity protection, integrity verification) , and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs) , error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs) , re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs) , demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK) , quadrature phase-shift keying (QPSK) , M-phase-shift keying (M-PSK) , M-quadrature amplitude modulation (M-QAM) ) . The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318Tx. Each transmitter 318Tx may modulate a radio frequency (RF) carrier with a respective spatial stream for transmission.

At the UE 350, each receiver 354Rx receives a signal through its respective antenna 352. Each receiver 354Rx recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT) . The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on channel estimates computed by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to the controller/processor 359, which implements layer 3 and layer 2 functionality.

The controller/processor 359 can be associated with at least one memory 360 that stores program codes and data. The at least one memory 360 may be referred to as a computer-readable medium. In the UL, the controller/processor 359 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets. The controller/processor 359 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with the DL transmission by the base station 310, the controller/processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression /decompression, and security (ciphering, deciphering, integrity protection, integrity verification) ; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 310 may be used by the TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354Tx. Each transmitter 354Tx may modulate an RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the base station 310 in a manner similar to that described in connection with the receiver function at the UE 350. Each receiver 318Rx receives a signal through its respective antenna 320. Each receiver 318Rx recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

The controller/processor 375 can be associated with at least one memory 376 that stores program codes and data. The at least one memory 376 may be referred to as a computer-readable medium. In the UL, the controller/processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets. The controller/processor 375 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

At least one of the TX processor 368, the RX processor 356, and the controller/processor 359 may be configured to perform aspects in connection with the active ambient IoT device initial access component 198 of FIG. 1.

At least one of the TX processor 316, the RX processor 370, and the controller/processor 375 may be configured to perform aspects in connection with the active ambient IoT device initial access configuration component 199 of FIG. 1.

FIG. 4 illustrates a diagram 400 of an RFID tag 404 that receives an energy transfer signal 406 from an RFID reader 402. Such an RFID tag 404 is one example of an ambient IoT device that may obtain energy from an energy transfer signal (or an energy signal) from an energy transmitter (e.g., the RFID reader 402) . The RFID tag 404, in some aspects, may also be described as, or comprise, an RFID device, an RF integrated circuit (RFIC) , an RFID chip, a backscatter device, or an IoT device. In some aspects, the RFID tag 404 may be included in an ambient IoT device as a passive backscattering and/or energy harvesting component associated with an energy storage and/or active RF components for signal generation. An energy transfer signal 406 may be used for various industrial IoT (IIoT) applications. For example, RFID technology may be used for inventory/asset management both inside and outside of warehouses, network sensors in factories, logistics devices, manufacturing settings, agricultural applications, smart homes, or other applications. RFID technology may also be deployed in association with cellular infrastructure for wireless applications. RFID devices may include a transponder (e.g., the RFID tag 404) that emits an information-bearing signal, such as a backscattered modulated information signal 408, upon receiving a signal from the RFID reader 402. That is, the RFID reader 402 may transmit the energy transfer signal 406 as well as an information signal to a passive RFID microchip (e.g., RFID tag 404) that operates without a battery source.

The RFID tag 404 may be configured to operate without the battery source at a low OPEX, low maintenance cost, and/or increased lifecycle. Other types of RFID tags may include battery sources. For example, semi-passive RFID devices and active RFID devices may have a battery source, but may also be associated with a higher cost.

Some aspects of wireless communication configured for interaction with passive ambient IoT devices (e.g., devices without independent signal generation capabilities) may be non-optimal for active ambient IoT devices. FIG. 5 is a call flow diagram 500 illustrating an inventory method associated with backscatter devices (e.g., ambient IoT devices) in accordance with some aspects of the disclosure. The method, in some aspects, may involve an interrogator 502 (e.g., a reader device such as an RFID reader 402 of FIG. 4, a tag reader, or a base station) capable of transmitting a signal carrying information and/or for backscattering to provide information to the interrogator 502. In some aspects, the method may further involve one or more ambient IoT devices such as ambient IoT device 504 that is at least capable of backscattering an impinging signal.

The interrogator 502, in some aspects, may transmit, and the ambient IoT device 504 may receive, a query 506 to initiate an inventory process (for subsequent rounds of a same inventory process, query 506 may be one of a QueryAdjust or QueryRep message) . The ambient IoT device 504 may, at 507, select a random value (e.g., a number between 0 and 2^Q-1 inclusive) and load the selected value into a local slot counter based on the query 506. If the selected value is “0” , the ambient IoT device 504 may transition to a “reply” state and backscatter, and the interrogator 502 may receive, a sixteen bit number 508 (e.g., a sixteen bit random number, or RN16) . If the random value selected at 507 is not equal to 0, the ambient IoT device 504 may decrement the number stored in the slot counter based on a transmission from the interrogator 502 until the number reaches 0 as described below.

The interrogator 502 may transmit, and the ambient IoT device 504 may receive, and an ACK message 510 containing the same sixteen bit number (e.g., the sixteen bit number 508) . Based on the ACK message 510, the ambient IoT device 504 may transition to an acknowledged state at 511 and may transmit, and the interrogator 502 may receive, a reply 512. While a successful inventory process for ambient IoT device 504 is illustrated above, in some aspects, the interrogator 502 may issue a NAK, in response to which all ambient IoT devices in the inventory round receiving the NAK may return to, or remain in, an “arbitrate” (or “un-inventoried” ) state without changing an inventoried flag (e.g., a bit indicating whether an ambient IoT device has been successfully inventoried in response to a query) .

To inventory additional ambient IoT devices (e.g., devices not having selected, or reached a slot counter value equal to 0) , the interrogator 502 may transmit, and the additional ambient IoT devices may receive, one or more QueryAdjust or QueryRep commands. For example, additional ambient IoT devices in an “arbitrate” or “reply” state that receive a QueryAdjust (e.g., if query 506 is a QueryAdjust) first adjust Q (increment, decrement, or leave unchanged) , then pick a random value in the range (0, 2^Q–1) , inclusive, and load this value into their slot counter. Tags that pick zero transition to the “reply” state and reply immediately as described in relation to the backscattering of the sixteen bit number 508 above. In some aspects, ambient IoT devices in the “arbitrate” state receiving a QueryRep (e.g., if query 506 is a QueryRep) decrement their slot counter every time they receive a QueryRep, transitioning to the “reply” state and backscattering the sixteen bit number 508 (e.g., a sixteen bit random number, or RN16) when their slot counter reaches 0000h (where “h” indicates that the number is a hexadecimal number with each digit taking on one of 16 values, or including 4 bits of information) . Ambient IoT devices whose slot counter reached 0000h, that replied, and were not acknowledged (including ambient IoT devices that responded to the original Query and were not acknowledged) return to arbitrate with a slot value of 0000h and decrement this slot value from 0000h to 7FFFh at the next QueryRep, thereby effectively preventing subsequent replies until the ambient IoT devices loads a new random value into its slot counter. This process may introduce a large latency as the number of “rounds” or iterations of this process to inventory a large number of ambient IoT devices may be quite large and may be subject to collisions between signaling associated with ambient IoT devices in close proximity selecting a same value. In some aspects, latency may be associated with unselected values in the range of acceptable values (e.g., for large Q many numbers may be unselected leading to rounds and/or iterations with no ambient IoT devices in the “reply” state) . These two sources of latency may render a certain level of latency nearly unavoidable, as the likelihood of collision decreases with higher Q, but the number of (empty) rounds increases with higher Q.

For ambient IoT devices with signal generation and/or amplification capabilities, other inventory methods based on a random access procedure may be possible. FIG. 6 is a call flow diagram 600 illustrating a method of random access for a wireless device in accordance with some aspects of the disclosure. Call flow diagram 600 illustrates a random access procedure for initial access of a UE 604 using base station 602. The base station 602 may transmit, and the UE 604 may receive, an SSB/PBCH 606 and a SIB1 608 that may be used by the UE 604 in the random access procedure. The UE 604 may select a set of Random-Access resources and may transmit, and the base station 602 may receive, a random access preamble 610 (e.g., a Msg1 associated with a PRACH or random access (RA) radio network temporary identifier (RNTI) (RA-RNTI) ) . The UE 604 may start ra-ResponseWindow and monitor for a random access response (RAR) from the base station 602. The base station 602 may transmit, and the UE 604 may receive, a RAR 612 (e.g., a Msg2 associated with a temporary cell-RNTI (TC-RNTI) ) .

The UE 604 may transmit, and the base station 602 may receive, a UE ID 614 (e.g., via a PUSCH) for contention resolution. The UE 604 may start an ra-ContentionResolutionTimer and monitor for a response associated with contention resolution. The base station 602 may transmit, and the UE 604 may receive, a contention resolution response 616. If the UE 604 does not transmit the preamble successfully or the contention resolution fails, the UE 604 may select a random backoff time according to a uniform distribution between 0 and a PREAMBLE_BACKOFF. In some aspects, before reaching the maximum allowed number of preamble retransmissions, the UE 604 may increase the transmit power of the preamble with a configured step value (e.g., a configured power step size) .

In the presence of a large number of active ambient IoT devices (e.g., type C ambient IoT devices capable of generating and/or amplifying a signal) , the random access procedure illustrated in FIG. 6 may be associated with many collisions between the active ambient IoT devices. Accordingly, various aspects relate generally to an initial access (or random access) procedure for an active ambient IoT device (e.g., a type C ambient IoT device) . Some aspects more specifically relate to a configuration for transmission and/or retransmission of an initial access message. In some examples, an active backscatter device (e.g., an ambient IoT device capable of storing energy and independently generating signals such as a type C ambient IoT device) may be configured to obtain a first indication of a plurality of resources for a preamble transmission from the active backscatter device and a corresponding plurality of downlink signal strength ranges, obtain a second indication for a set of power ramp steps associated with the plurality of resources, and perform a random access procedure associated with a network device based on the first indication and the second indication. In some examples, a network device (e.g., a base station) may be configured to output a first indication of a plurality of resources for a preamble transmission from at least one active backscatter device and a corresponding plurality of downlink signal strength ranges, output a second indication for a set of power ramp steps associated with the plurality of resources, and receive at least one random access message associated with the at least one active backscatter device based on the first indication and the second indication.

FIG. 7 is a set of diagrams (e.g., diagram 700, diagram 730, diagram 740, and diagram 770) illustrating a plurality of resources that may be associated with a random access (or initial access) procedure associated with a measured and/or detected DL signal strength in accordance with some aspects of the disclosure. In some aspects, an ambient IoT device (in a plurality of ambient IoT devices) may measure a DL signal strength from a base station to which it may attempt to connect. The ambient IoT device may select parameters (e.g., resources and/or a transmission power) for a random access procedure based on the measured DL signal strength, a configuration for a plurality of resources for a preamble transmission and a corresponding plurality of downlink signal strength ranges, and other characteristics of the ambient IoT device (e.g., an amplification capability) . The measured DL signal strength, in some aspects, may be seen as a proxy for (or a measure of) a distance from a base station (and a minimum transmission power for a successful preamble transmission associated with a random access procedure) . For example, diagram 730 illustrates a base station 735 and areas (e.g., area 731 associated with a first bin, area 732 associated with a second bin, and area 733 associated with an N^th bin) that may be associated with different DL signal strength ranges. Accordingly, active ambient IoT devices measuring a high DL signal strength (due to being in area 731 that is in close proximity to the base station 735) may use a low transmission power for preamble transmission and active ambient IoT devices measuring a lower DL signal strength may use a higher transmission power for preamble transmission.

Diagram 700 illustrates a first correspondence between a plurality of DL signal strength ranges and a set of frequency resources. For example, a first DL signal strength range (e.g., a first bin 711) may correspond to a first frequency resource 721 (e.g., a first frequency range centered around a first frequency f₀) and may be associated with a first threshold 701 (an upper threshold P_max, 1) and a second threshold 702 (alower threshold P_min, 1) , a second DL signal strength range (e.g., a second bin 712) may correspond to a second frequency resource 722 (e.g., a second frequency range centered around a second frequency f₁) and may be associated with the second threshold 702 (an upper threshold P_max, 2) and a third threshold 703 (alower threshold P_min, 2) , and an N^th DL signal strength range (e.g., an N^th bin 713) may correspond to an N^th frequency resource 723 (e.g., an N^th frequency range centered around an N^th frequency f_N-1) and may be associated with a fourth threshold 704 (an upper threshold P_max, N) and a fifth threshold 705 (alower threshold P_min, N) . The correspondence indicated in diagram 700 may be provided to a set of active ambient IoT devices to use to determine a resource for a preamble transmission associated with a random (or initial) access procedure. In some aspects, each frequency may be associated with a different initial transmission power. For example, the first frequency resource 721 may be associated with a first (lowest) power, the second frequency resource 722 may be associated with a second (higher) power, and the N^th frequency resource 723 may be associated with an N^th (highest) power.

Diagram 740 illustrates a first correspondence between a plurality of DL signal strength ranges and a set of frequency resources that may be based on an amplification capability of the active ambient IoT device. The DL signal strength ranges may be the same as described in relation to diagram 700 but the correspondence to frequency resources may be modified by an amplification capability of the active ambient IoT device. For example, a first DL signal strength range (e.g., a first bin 751) may correspond to a first frequency resource 761 (e.g., a first frequency range centered around a first frequency f₀) for a first amplification capability (Amp₁) and a second frequency resource 762 (e.g., a second frequency range centered around a second frequency f₁) for a second amplification capability (Amp₂) . A second DL signal strength range (e.g., a second bin 752) may correspond to the second frequency resource 762 for a first amplification capability (Amp₁) , a third frequency resource (e.g., a third frequency range centered around a third frequency f₂) for a second amplification capability (Amp₂) , and a first frequency resource 762 for a third amplification capability (Amp₃) . An N^th DL signal strength range (e.g., an N^th bin 753) may correspond to an N^th frequency resource 763 (e.g., an N^th frequency range centered around an N^th frequency f_N-1) for a first amplification capability (Amp₁) and an N^th-1 frequency resource 762 (e.g., an N^th-1 frequency range centered around an N^th-1 frequency f_N-2) for the third amplification capability (Amp₃) . The correspondence indicated in diagram 740 may be provided to a set of active ambient IoT devices to use to determine a resource for a preamble transmission associated with a random (or initial) access procedure. In some aspects, each frequency may be associated with a different initial transmission power. For example, the first frequency resource 761 may be associated with a first (lowest) power, the second frequency resource 762 may be associated with a second (higher) power, and the N^th frequency resource 763 may be associated with an N^th (highest) power.

Diagram 770 illustrates a first correspondence between a plurality of DL signal strength ranges and a set of frequency resources that may be modified by an amplification capability of the active ambient IoT device. The DL signal strength ranges may be the same as described in relation to diagram 700 but the correspondence to frequency resources may be modified by an amplification capability of the active ambient IoT device. As opposed to the correspondence illustrated in diagram 740 in which multiple DL signal strength ranges may correspond to a same frequency resource, the frequency resources associated with each bin may be disjoint. For example, a first DL signal strength range (e.g., a first bin 781) may correspond to a first frequency resource 791 (e.g., a first frequency range centered around a first frequency f_0+Δ) for a first amplification capability (Amp₁) , a second frequency resource 792 (e.g., a second frequency range centered around a second frequency f₀) for a second amplification capability (Amp₂) , and a third frequency resource 793 (e.g., a third frequency range centered around a third frequency f_0-Δ) for a third amplification capability (Amp₃) . A second DL signal strength range (e.g., a second bin 782) may correspond to a fourth frequency resource (e.g., a fourth frequency range centered around a fourth frequency f_1+Δ) for a first amplification capability (Amp₁) , a fifth frequency resource (e.g., a fifth frequency range centered around a fifth frequency f₁) for a second amplification capability (Amp₂) , and a sixth frequency resource (e.g., a sixth frequency range centered around a sixth frequency f_1-Δ) for a third amplification capability (Amp₃) . A third DL signal strength range (e.g., a third bin 783) may correspond to a seventh frequency resource (e.g., a seventh frequency range centered around a seventh frequency f_N-1+Δ) for a first amplification capability (Amp₁) , an eighth frequency resource (e.g., an eighth frequency range centered around an eighth frequency f_N-1) for a second amplification capability (Amp₂) , and a ninth frequency resource (e.g., a ninth frequency range centered around a ninth frequency f_N-1-Δ) for a third amplification capability (Amp₃) . The correspondence indicated in diagram 770 may be provided to a set of active ambient IoT devices to use to determine a resource for a preamble transmission associated with a random (or initial) access procedure. In some aspects, each frequency may be associated with a configured initial transmission power.

FIG. 8 is a set of diagrams (e.g., diagram 800, diagram 820, diagram 840, and diagram 860) illustrating a first set of power ramp and repetition patterns that may be used for an initial preamble transmission and retransmissions in association with a random access (or initial access) procedure for an active ambient IoT device in accordance with some aspects of the disclosure. In some aspects, the power ramp and repetition patterns may be based on, or associated with the frequency resources corresponding to the DL signal strength ranges as described above in relation to FIG. 7. Diagrams 800 to 860 illustrate a set of N frequency resources (e.g., a first frequency resource 811 (e.g., a first frequency range centered around a first frequency f₀) , a second frequency resource 812 (e.g., a second frequency range centered around a second frequency f₁) , and an N^th frequency resource 813 (e.g., an N^th frequency range centered around an N^th frequency f_N-1) associated with a set of N transmission powers. The set of N transmission powers may be indicated based on an initial, or base, power (e.g., P₀) and one or more additive or multiplicative factors (e.g., a common step size, or Δ, or a set of offset values, ΔP_i for i∈ [1, …, N-1] , corresponding to the N-1 transmission powers other than the initial power) . The transmission (or retransmissions) may further be associated with a number of repetitions, where the number of repetitions associated with a particular transmission (or retransmission) may be indicated by a power ramp and repetition pattern indication. Each step in the power ramp and repetition pattern may be separated by a retransmission backoff time.

In some aspects, the power ramp and repetition pattern may include and/or indicate increasing, after a failure of each previous preamble (re) transmission, a transmission power associated with a subsequent preamble transmission until reaching a maximum power. While increasing the transmission power between steps, the power and repetition pattern may further include and/or indicate increasing, after the failure of each previous preamble transmission, the power associated with a set of subsequent preamble transmissions while maintaining a first number of repetitions associated with the set of subsequent preamble transmissions and, upon using the maximum power for a subsequent preamble transmission in the set of subsequent preamble transmissions, increasing the number of repetitions associated with one or more subsequent preamble transmissions at the maximum power until reaching the maximum number of repetitions. For example, diagram 800 illustrates that a first transmission 801 may be transmitted with an initial power (P₀) and via a first number of repetitions. If the first transmission 801 fails, the power ramp and repetition pattern may indicate that a first (subsequent) retransmission 802 be transmitted with a same number of repetitions and a different transmission power (P₀+ΔP₁) and a different frequency resource (where, in some aspects, each frequency resource is associated with a particular transmission power or power ramp step) . Similarly, after N-1 such failures, a retransmission 803 may be transmitted with a maximum transmission power (P₀+ΔP_N-1) and via the first number of repetitions. Subsequent retransmissions (e.g., retransmission 804) may maintain the maximum transmission power (P₀+ΔP_N-1) and increase the number of repetitions until a maximum number of repetitions is reached. If the retransmission 804 fails, the random access procedure may be determined to be a failure and a new random access procedure may be initiated after a random access procedure backoff time.

In some aspects, the power and repetition pattern may include and/or indicate increasing, after the failure of each previous preamble transmission, a number of repetitions associated with the subsequent preamble transmission and the transmission power associated with the subsequent preamble transmission until reaching a maximum number of repetitions and the maximum power. For example, diagram 820 illustrates that a first transmission 821 may be transmitted with an initial power (P₀) and via a first number of repetitions. If the first transmission 821 fails, the power ramp and repetition pattern may indicate that a first (subsequent) retransmission 822 be transmitted with a second number of repetitions (e.g., a larger number of repetitions) and a different transmission power (P₀+ΔP₁) and frequency resource. Similarly, after N-1 such failures, a retransmission 823 may be transmitted with a maximum transmission power (P₀+ΔP_N-1) and via an N^th number of repetitions. Subsequent retransmissions (e.g., retransmission 824) may maintain the maximum transmission power (P₀+ΔP_N-1) and increase the number of repetitions until a maximum number of repetitions is reached. While the number of unique repetition numbers (e.g., the number of steps associated with the number of repetitions) is illustrated as being greater than the number of unique transmission powers (e.g., the number of steps associated with the transmission power) , in some aspects, the number of unique repetition numbers may be less than the number of unique transmission powers and once the maximum number of repetitions has been reached, it may be used for subsequent retransmissions with higher transmission powers. Similarly, if the number of unique repetitions numbers is the same as the number of unique transmission powers, the pattern may end at the retransmission 823 (where the maximum number of repetitions and the maximum transmission power is reached at a same retransmission) . If the retransmission 824 fails, the random access procedure may be determined to be a failure and a new random access procedure may be initiated after a random access procedure backoff time.

The power and repetition pattern, in some aspects, may include and/or indicate increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions. For example, the power and repetition pattern, in some aspects, may include and/or indicate increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the set of subsequent preamble transmissions while maintaining a first power associated with the set of subsequent preamble transmissions and, upon using the maximum number of repetitions for the subsequent preamble transmission in the set of subsequent preamble transmissions and based on the second indication, increasing the power associated with one or more subsequent preamble transmissions at the maximum number of repetitions until reaching the maximum power. For example, diagram 840 illustrates that a first transmission 841 may be transmitted with an initial power (P₀) and via a first number of repetitions. If the first transmission 841 fails, the power ramp and repetition pattern may indicate that a subsequent retransmission be transmitted with an increasing number of repetitions until reaching a maximum number of repetitions at retransmission 842. A next retransmission 843 may be transmitted with the maximum number of repetitions and an increased transmission power (P₀+ΔP₁) via a second frequency resource 812. Similarly, after N-2 additional failures, a retransmission 844 may be transmitted with the maximum number of repetitions and with a maximum transmission power (P₀+ΔP_N-1) via the N^th frequency resource 813. If the retransmission 844 fails, the random access procedure may be determined to be a failure and a new random access procedure may be initiated after a random access procedure backoff time.

In some aspects, the power and repetition pattern, in some aspects, may include and/or indicate, iteratively, (1) beginning from the first number of repetitions associated with the preamble transmission at a current power, increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions, and, after the failure of a preamble transmission associated with the maximum number of repetitions, (2) increasing the current power based on the second indication until the maximum power is reached. For example, diagram 860 illustrates that a first transmission 861 may be transmitted with an initial power (P₀) and via a first number of repetitions. If the first transmission 861 fails, the power ramp and repetition pattern may indicate that subsequent retransmissions be transmitted with an increasing number of repetitions until reaching a maximum number of repetitions at retransmission 862, where the set of (re) transmissions 863 represents a first stage of the iterative process. A current transmission power may be increased (and a corresponding frequency may be identified) for a next set of retransmissions 864 during the second stage of the iterative process. After the transmission power has been increased the process may iterate and the next set of retransmission 864 may be transmitted beginning with a first retransmission using the first number of repetitions (e.g., the same number of repetitions as used for transmission 861) until the maximum number of repetitions is reached and the process proceeds to increase a current transmission power. The process may iterate (or repeat) until a transmission power cannot be increase at the second stage of the iterative process (or loop) , e.g., after the set of retransmissions 865 associated with the maximum transmission power (P₀+ΔP_N-1) via the N^th frequency resource 813. If the set of retransmissions 865 fails, the random access procedure may be determined to be a failure and a new random access procedure may be initiated after a random access procedure backoff time.

FIG. 9 is a set of diagrams (e.g., diagram 900, diagram 930, and diagram 960) illustrating a second set of power ramp and repetition patterns that may be used for an initial preamble transmission and retransmissions in association with a random access (or initial access) procedure for an active ambient IoT device in accordance with some aspects of the disclosure. In some aspects, the power ramp and repetition patterns may be based on, or associated with the frequency resources corresponding to the DL signal strength ranges as described above in relation to FIG. 7. Diagrams 900 to 960 illustrate a set of N frequency resources (e.g., a first frequency resource 911 (e.g., a first frequency range centered around a first frequency f₀) , a second frequency resource 912 (e.g., a second frequency range centered around a second frequency f₁) , and an N^th frequency resource 913 (e.g., an N^th frequency range centered around an N^th frequency f_N-1) associated with a set of N transmission powers. The set of N transmission powers may be indicated based on an initial, or base, power (e.g., P₀) and one or more additive or multiplicative factors (e.g., a common step size, or Δ, or a set of offset values, ΔP_i for i∈ [1, …, N-1] , corresponding to the N-1 transmission powers other than the initial power) . The transmission (or retransmissions) may further be associated with a number of repetitions, where the number of repetitions associated with a particular transmission (or retransmission) may be indicated by a power ramp and repetition pattern indication.

In some aspects, the second set of power ramp and repetition patterns may include and/or indicate increasing, after a failure of a first configured number of previous preamble transmissions (e.g., K failed transmissions) , the number of repetitions associated with the set of subsequent preamble transmissions until reaching the maximum number of repetitions and increasing, after a failure of a second configured number of previous preamble transmissions (e.g., M failed transmissions) , the power associated with the subsequent preamble transmission until reaching the maximum power. Diagrams 900, 930, and 960 illustrate the second set of power ramp and repetition patterns for M>K, M<K, and M=K, respectively. Diagram 900 further illustrates that transmissions from a first UE associated with a first bin and from a second UE associated with a second bin using a same power ramp and repetition may not collide.

Diagram 900 illustrates that a first UE (e.g., a first active ambient IoT device) may transmit a first transmission 901 with a first number of repetitions and at a first (initial, or base) transmission power (P₀) via the first frequency resource 911, while a second UE (e.g., a second active ambient IoT device) may transmit a first transmission 906 with a first number of repetitions at second transmission power (P₀+ΔP₁) via the second frequency resource 912. In some aspects, the selection of the first frequency resource 911 by the first UE and the selection of the second frequency resource 912 by the second UE may be based on a different measured DL signal strength at the first and second UEs and/or may be based on different amplification capabilities of the first and second UEs as described in relation to FIG. 7. Each of the first UE and the second UE may perform a set of K (re) transmissions before increasing a number of repetitions associated with each repetition at retransmission 902 and 907, respectively. After a set of M (re) transmissions (ending with retransmission 903 and retransmission 908 for the first UE and the second UE, respectively) , each of the first UE and the second UE may increase a power associated with subsequent retransmissions (e.g., retransmission 904 for the first UE) and transition to a different frequency resource. The process for the second UE and the first UE may proceed until the transmission 909 and 905, respectively, at the highest transmission power. If the transmission 909 and 905 fail, the random access procedure may be determined to be a failure and a new random access procedure may be initiated after a random access procedure backoff time. If each UE follows a same power and repetition pattern, collisions may be avoided based on the use of different resources for each (re) transmission.

Diagram 930 illustrates that a first transmission 931 with a first number of repetitions and at a first (initial, or base) transmission power (P₀) via the first frequency resource 911. After performing a set of M (re) transmissions, a subsequent retransmission 932 may be transmitted with an increased transmission power (P₀+ΔP₁) via the second frequency resource 912. After a set of K (re) transmissions, a subsequent retransmission 933 may be transmitted with an increased number of repetitions. The process may proceed until reaching a maximum number of repetitions and/or maximum transmission power and if that transmission fails, the random access procedure may be determined to be a failure and a new random access procedure may be initiated after a random access procedure backoff time.

Diagram 960 illustrates that a first transmission 961 with a first number of repetitions and at a first (initial, or base) transmission power (P₀) via the first frequency resource 911. After performing a set of M (or K) (re) transmissions, a subsequent retransmission 962 may be transmitted with an increased number of repetitions and an increased transmission power (P₀+ΔP₁) via the second frequency resource 912. After additional sets of M (or K) (re) transmissions, a subsequent retransmission 963 may be transmitted with a maximum number of repetitions and a maximum transmission power (P₀+ΔP_N-1) via the N^th frequency resource 913. If the retransmission 963 fails, the random access procedure may be determined to be a failure and a new random access procedure may be initiated after a random access procedure backoff time.

FIG. 10 is a diagram 1000 illustrating a power ramp and repetition pattern that may be used for an initial preamble transmission and retransmissions in association with a random access (or initial access) procedure for an active ambient IoT device in accordance with some aspects of the disclosure. In some aspects, the power ramp and repetition pattern in diagram 1000 may be similar to the power ramp and repetition pattern illustrated in diagram 820, but may be adjusted to ramp up (e.g., increase the transmission power and the number of repetitions) more quickly. The adjustment of the speed of the ramp up, in some aspects, may be based on an energy status of the ambient IoT device and the power ramp and repetition pattern may indicate different power ramp and repetition patterns for different energy status or conditions.

For example, diagram 1000 illustrates a set of N frequency resources (e.g., a first frequency resource 1011 (e.g., a first frequency range centered around a first frequency f₀) , a second frequency resource 1012 (e.g., a second frequency range centered around a second frequency f₁) , a third frequency resource 1014 (e.g., a third frequency range centered around a third frequency f₂) , a fourth frequency resource 1015 (e.g., a fourth frequency range centered around a fourth frequency f₃) , a fifth frequency resource 1016 (e.g., a fifth frequency range centered around a fifth frequency f₄) , and an N^th frequency resource 1013 (e.g., an N^th frequency range centered around an N^th frequency f_N-1) associated with a set of N transmission powers. The set of N transmission powers may be indicated based on an initial, or base, power (e.g., P₀) and one or more additive or multiplicative factors (e.g., a common step size, or Δ, or a set of offset values, ΔP_i for i∈ [1, …, N-1] , corresponding to the N-1 transmission powers other than the initial power) . The transmission (or retransmissions) may further be associated with a number of repetitions, where the number of repetitions associated with a particular transmission (or retransmission) may be indicated by a power ramp and repetition pattern indication.

For example, diagram 1000 illustrates that a first transmission 1001 may be transmitted with an initial power (P₀) and via a first number of repetitions. If the first transmission 1001 fails, the power ramp and repetition pattern may indicate that a first (subsequent) retransmission 1002 be transmitted with a second number of repetitions (e.g., a larger number of repetitions) and a different transmission power (P₀+ΔP₂) and frequency resource (e.g., a third frequency resource 1014) . If the retransmission 1002 fails, the power ramp and repetition pattern may indicate that a retransmission 1003 be transmitted with a third number of repetitions (e.g., a larger number of repetitions) and a larger transmission power (P₀+ΔP₄) and associated frequency resource (e.g., a fifth frequency resource 1016) . Similarly, after a configured number of failures, a retransmission 1004 may be transmitted with a maximum transmission power (P₀+ΔP_N-1) and via an N^th number of repetitions. If the retransmission 1004 fails, the random access procedure may be determined to be a failure and a new random access procedure may be initiated after a random access procedure backoff time.

FIG. 11 is a call flow diagram 1100 illustrating a method for an initial access (or random access) procedure associated with an active ambient IoT device (e.g., a type C ambient IoT device) in accordance with some aspects of the disclosure. The method is illustrated in relation to a base station 1102 (e.g., as an example of a network device or network node that may include one or more components of a disaggregated base station) in communication with an ambient IoT device 1104 (e.g., as an example of an active backscatter device, an active ambient IoT device, a Type C ambient IoT device, etc. ) . The functions ascribed to the base station 1102, in some aspects, may be performed by one or more components of a network entity, a network node, or a network device (asingle network entity/node/device or a disaggregated network entity/node/device as described above in relation to FIG. 1) . Similarly, the functions ascribed to the ambient IoT device 1104, in some aspects, may be performed by one or more components of a an ambient IoT device supporting communication with (e.g., signal generation for) a network entity/node/device. Accordingly, references to “transmitting” in the description below may be understood to refer to a first component of the base station 1102 (or the ambient IoT device 1104) outputting (or providing) an indication of the content of the transmission to be transmitted by a different component of the base station 1102 (or the ambient IoT device 1104) . Similarly, references to “receiving” in the description below may be understood to refer to a first component of the base station 1102 (or the ambient IoT device 1104) receiving a transmitted signal and outputting (or providing) the received signal (or information based on the received signal) to a different component of the base station 1102 (or the ambient IoT device 1104) .

The base station 1102 may transmit, and the ambient IoT device 1104 may receive, resource configuration 1106. In some aspects, the resource configuration 1106 may indicate a plurality of resources for a preamble transmission from at least one active backscatter device (e.g., the ambient IoT device 1104) and a corresponding plurality of DL signal strength ranges as described in relation to FIG. 7. In some aspects, for at least a first DL signal strength range, corresponding resources may include multiple sets of resources (as described in relation to one of diagram 740 or diagram 770) , where each set of resources is associated with a range of amplification capabilities of the ambient IoT devices. In some aspects, each indicated resource may be associated with a particular transmission power as described above in relation to FIGs. 8 and 9. The resource configuration 1106, in some aspects, may be a known (or pre-configured) configuration for the frequency resources corresponding to different DL signal strengths.

The base station 1102 may transmit, and the ambient IoT device 1104 may receive, a retransmission configuration 1107 including a power ramp configuration 1108 and a repetition pattern 1109. In some aspects, the retransmission configuration 1107 may correspond to the power ramp and repetition pattern described above in relation to FIGs. 8 and 9. The base station 1102 may also transmit, and the ambient IoT device 1104 may receive, one or more RS 1110. The ambient IoT device 1104 may measure the RS to determine a DL signal strength at 1112. Based on the DL signal strength measured at 1112, the ambient IoT device 1104 may select, at 1114, a frequency resource (and an associated transmission power) for an initial transmission of a preamble for a random access procedure.

The ambient IoT device 1104 may transmit, and the base station 1102 may receive (or fail to receive) , the initial transmission of the preamble 1116. If the initial transmission of the preamble 1116 is unsuccessful (e.g., a NAK, or no response, is received from the base station 1102) the ambient IoT device 1104 may maintain a retransmission counter at 1118 and may transmit, and the base station 1102 may receive, one or more preamble retransmissions 1120 based on the retransmission configuration 1107 (e.g., the power ramp configuration 1108 and the repetition pattern 1109) . The one or more preamble retransmissions 1120 may be based on one of the power and repetition patterns described above in relation to FIGs. 8, 9, and 10. Based on the one or more preamble retransmissions 1120, the base station 1102 and the ambient IoT device 1104 may, at 1122, establish a connection (e.g., based on a successful reception at the base station 1102) or the ambient IoT device 1104 may begin a new initial access procedure (e.g., based on the initial transmission of the preamble 1116 and the one or more preamble retransmissions 1120 being unsuccessful) .

FIG. 12 is a flowchart 1200 of a method of wireless communication. The method may be performed by a wireless device such as an active ambient IoT device or a type C ambient IoT device (e.g., the UE 104; the RFID tag 404; the ambient IoT device 504, 1104; the apparatus 1604) . At 1202, the ambient IoT device may obtain a first indication of a plurality of resources for a preamble transmission from the active backscatter device and a corresponding plurality of downlink signal strength ranges. For example, 1202 may be performed by application processor (s) 1606, cellular baseband processor (s) 1624, transceiver (s) 1622, antenna (s) 1680, and/or an active ambient IoT device initial access component 198 of FIG. 16 or by processor (s) 1824, antenna (s) 1880, and/or an active ambient IoT device initial access component 198 of FIG. 18. Obtaining the first indication, in some aspects, may be based on a known (or pre-configured) configuration of the plurality of resources or obtaining the first indication may include receiving the first indication from the network device. In some aspects, for at least a first downlink signal strength range, the corresponding resources include multiple sets of resources, where each set of resources is associated with a range of amplification capabilities of backscatter (or ambient IoT) devices. For example, referring to FIGs. 7 and 11, the ambient IoT device 1104 may receive resource configuration 1106 indicating one of the configurations illustrated in diagram 700, diagram 740, or diagram 770.

At 1204, the ambient IoT device may obtain a second indication for a set of power ramp steps associated with the plurality of resources. In some aspects, the set of power ramp steps may include different power ramp steps for different energy statuses (e.g., amounts of energy or energy harvesting to consumption ratios) where for a lower stored energy a power ramp step may be larger to increase a likelihood of success in a smaller number of repetitions and/or retransmissions. For example, 1204 may be performed by application processor (s) 1606, cellular baseband processor (s) 1624, transceiver (s) 1622, antenna (s) 1680, and/or an active ambient IoT device initial access component 198 of FIG. 16 or by processor (s) 1824, antenna (s) 1880, and/or an active ambient IoT device initial access component 198 of FIG. 18. In some aspects, the second indication for the set of power ramp steps may indicate a power ramp step that applies to a plurality of different classes of backscatter devices with different capabilities. The second indication for the set of power ramp steps, in some aspects, may indicate a power ramp step for each of a plurality of different classes of backscatter (or ambient IoT) devices with different capabilities, where the power ramp step may be different for each of the plurality of different classes of backscatter devices. For example, referring to FIGs. 8, 9, 10, and 11, the ambient IoT device 1104 may receive retransmission configuration 1107 (and more specifically, power ramp configuration 1108) indicating a set of power ramp steps according to one of the power and repetition patterns illustrated in FIGs. 8, 9, and 10.

In some aspects, the ambient IoT device may obtain a third indication for a repetition pattern associated with the preamble transmission. Obtaining the third indication, in some aspects, may include obtaining a number of repetitions associated with at least one of a first transmission or a retransmission. In some aspects, the third indication may include or be associated with a fourth indication of a maximum number of retransmissions. The second and third indication, in some aspects, may be included in a power and repetition pattern indication and/or configuration. In some aspects, each preamble transmission is associated with one or more repetitions and the repetition pattern (alternatively referred to as a power and repetition pattern) may indicate increasing, after a failure of each previous preamble transmission and based on the second indication, a power associated with a subsequent preamble transmission until reaching a maximum power. The repetition pattern, in some aspects, may indicate increasing, after the failure of each previous preamble transmission and based on the second indication, a number of repetitions associated with the subsequent preamble transmission and the power associated with the subsequent preamble transmission until reaching a maximum number of repetitions and the maximum power. In some aspects, the repetition pattern may indicate increasing, after the failure of each previous preamble transmission and based on the second indication, the power associated with a set of subsequent preamble transmissions while maintaining a first number of repetitions associated with the set of subsequent preamble transmissions and, upon using the maximum power for a subsequent preamble transmission in the set of subsequent preamble transmissions, increasing the number of repetitions associated with one or more subsequent preamble transmissions at the maximum power until reaching the maximum number of repetitions.

The repetition pattern in some aspects, may indicate increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions. In some aspects, the repetition pattern may indicate increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the set of subsequent preamble transmissions while maintaining a first power associated with the set of subsequent preamble transmissions and, upon using the maximum number of repetitions for the subsequent preamble transmission in the set of subsequent preamble transmissions and based on the second indication, increasing the power associated with one or more subsequent preamble transmissions at the maximum number of repetitions until reaching the maximum power. The repetition pattern in some aspects, may indicate increasing, after a failure of a first configured number of previous preamble transmissions, the number of repetitions associated with the set of subsequent preamble transmissions until reaching the maximum number of repetitions and increasing, after a failure of a second configured number of previous preamble transmissions and based on the second indication, the power associated with the subsequent preamble transmission until reaching the maximum power. In some aspects, the repetition pattern may indicate iteratively, (1) beginning from the first number of repetitions associated with the preamble transmission at a current power, increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions, and, after the failure of a preamble transmission associated with the maximum number of repetitions, (2) increasing the current power based on the second indication until the maximum power is reached. For example, referring to FIGs. 8, 9, 10, and 11, the ambient IoT device 1104 may receive retransmission configuration 1107 (and more specifically, repetition pattern 1109) indicating a repetition pattern according to one of the power and repetition patterns illustrated in FIGs. 8, 9, and 10.

At 1208, the ambient IoT device may perform a random access procedure associated with a network device based on the first indication and the second indication. In some aspects, the random access procedure may further be based on the third indication. As part of performing the random access procedure at 1208, the ambient IoT device may select a resource to use for the preamble transmission from the plurality of resources based on a downlink signal strength associated with the network device. In some aspects, selecting the resource to use for the preamble transmission may further be based on an amplification capability of the active backscatter device. To perform the random access procedure at 1208, the ambient IoT device may, maintain a retransmission counter, e.g., to determine when to increase a power or number of repetitions based on the second or third indication. In some aspects, selecting the resource to use for the preamble transmission may further be based on an amplification capability of the active backscatter device. For example, 1208 may be performed by application processor (s) 1606, cellular baseband processor (s) 1624, transceiver (s) 1622, antenna (s) 1680, and/or an active ambient IoT device initial access component 198 of FIG. 16 or by processor (s) 1824, antenna (s) 1880, and/or an active ambient IoT device initial access component 198 of FIG. 18. In some aspects, performing the random access procedure may include performing an initial transmission of a preamble and one or more retransmissions based on the second indication and the third indication of the power ramp steps and the repetition pattern until a successfully received transmission. For example, referring to FIGs. 7 and 11, the ambient IoT device 1104 may select, at 1114, a frequency resource (and an associated transmission power) for an initial transmission of a preamble 1116 for a random access procedure based on a DL signal strength measured at 1112 and, in some aspects, based on an amplification capability of the ambient IoT device 1104. The ambient IoT device 1104 may further maintain a retransmission counter at 1118 and may transmit one or more preamble retransmissions 1120 based on the retransmission configuration 1107 (e.g., the power ramp configuration 1108 and the repetition pattern 1109) . The one or more preamble retransmissions 1120 may be based on one of the power and repetition patterns described above in relation to FIGs. 8, 9, and 10.

FIG. 13 is a flowchart 1300 of a method of wireless communication. The method may be performed by a wireless device such as an active ambient IoT device or a type C ambient IoT device (e.g., the UE 104; the RFID tag 404; the ambient IoT device 504, 1104; the apparatus 1604) . At 1302, the ambient IoT device may obtain a first indication of a plurality of resources for a preamble transmission from the active backscatter device and a corresponding plurality of downlink signal strength ranges. For example, 1302 may be performed by application processor (s) 1606, cellular baseband processor (s) 1624, transceiver (s) 1622, antenna (s) 1680, and/or an active ambient IoT device initial access component 198 of FIG. 16 or by processor (s) 1824, antenna (s) 1880, and/or an active ambient IoT device initial access component 198 of FIG. 18. Obtaining the first indication, in some aspects, may be based on a known (or pre-configured) configuration of the plurality of resources or obtaining the first indication may include receiving the first indication from the network device. In some aspects, for at least a first downlink signal strength range, the corresponding resources include multiple sets of resources, where each set of resources is associated with a range of amplification capabilities of backscatter (or ambient IoT) devices. For example, referring to FIGs. 7 and 11, the ambient IoT device 1104 may receive resource configuration 1106 indicating one of the configurations illustrated in diagram 700, diagram 740, or diagram 770.

At 1304, the ambient IoT device may obtain a second indication for a set of power ramp steps associated with the plurality of resources. In some aspects, the set of power ramp steps may include different power ramp steps for different energy statuses (e.g., amounts of energy or energy harvesting to consumption ratios) where for a lower stored energy a power ramp step may be larger to increase a likelihood of success in a smaller number of repetitions and/or retransmissions. For example, 1304 may be performed by application processor (s) 1606, cellular baseband processor (s) 1624, transceiver (s) 1622, antenna (s) 1680, and/or an active ambient IoT device initial access component 198 of FIG. 16 or by processor (s) 1824, antenna (s) 1880, and/or an active ambient IoT device initial access component 198 of FIG. 18. In some aspects, the second indication for the set of power ramp steps may indicate a power ramp step that applies to a plurality of different classes of backscatter devices with different capabilities. The second indication for the set of power ramp steps, in some aspects, may indicate a power ramp step for each of a plurality of different classes of backscatter (or ambient IoT) devices with different capabilities, where the power ramp step may be different for each of the plurality of different classes of backscatter devices. For example, referring to FIGs. 8, 9, 10, and 11, the ambient IoT device 1104 may receive retransmission configuration 1107 (and more specifically, power ramp configuration 1108) indicating a set of power ramp steps according to one of the power and repetition patterns illustrated in FIGs. 8, 9, and 10.

At 1306, the ambient IoT device may obtain a third indication for a repetition pattern associated with the preamble transmission. Obtaining the third indication, in some aspects, may include obtaining a number of repetitions associated with at least one of a first transmission or a retransmission. In some aspects, the third indication may include or be associated with a fourth indication of a maximum number of retransmissions. The second and third indication, in some aspects, may be included in a power and repetition pattern indication and/or configuration. For example, 1306 may be performed by application processor (s) 1606, cellular baseband processor (s) 1624, transceiver (s) 1622, antenna (s) 1680, and/or an active ambient IoT device initial access component 198 of FIG. 16 or by processor (s) 1824, antenna (s) 1880, and/or an active ambient IoT device initial access component 198 of FIG. 18. In some aspects, each preamble transmission is associated with one or more repetitions and the repetition pattern (alternatively referred to as a power and repetition pattern) may indicate increasing, after a failure of each previous preamble transmission and based on the second indication, a power associated with a subsequent preamble transmission until reaching a maximum power. The repetition pattern, in some aspects, may indicate increasing, after the failure of each previous preamble transmission and based on the second indication, a number of repetitions associated with the subsequent preamble transmission and the power associated with the subsequent preamble transmission until reaching a maximum number of repetitions and the maximum power. In some aspects, the repetition pattern may indicate increasing, after the failure of each previous preamble transmission and based on the second indication, the power associated with a set of subsequent preamble transmissions while maintaining a first number of repetitions associated with the set of subsequent preamble transmissions and, upon using the maximum power for a subsequent preamble transmission in the set of subsequent preamble transmissions, increasing the number of repetitions associated with one or more subsequent preamble transmissions at the maximum power until reaching the maximum number of repetitions.

At 1308, the ambient IoT device may perform a random access procedure associated with a network device based on the first indication and the second indication. In some aspects, the random access procedure may further be based on the third indication. As part of performing the random access procedure at 1308, the ambient IoT device may, at 1309, select a resource to use for the preamble transmission from the plurality of resources based on a downlink signal strength associated with the network device. In some aspects, selecting the resource to use for the preamble transmission may further be based on an amplification capability of the active backscatter device. To perform the random access procedure at 1308, the ambient IoT device may, at 1311, maintain a retransmission counter, e.g., to determine when to increase a power or number of repetitions based on the second or third indication. In some aspects, selecting the resource to use for the preamble transmission may further be based on an amplification capability of the active backscatter device. For example, 1308, 1309, and, 1311 may be performed by application processor (s) 1606, cellular baseband processor (s) 1624, transceiver (s) 1622, antenna (s) 1680, and/or an active ambient IoT device initial access component 198 of FIG. 16 or by processor (s) 1824, antenna (s) 1880, and/or an active ambient IoT device initial access component 198 of FIG. 18. In some aspects, performing the random access procedure may include performing an initial transmission of a preamble and one or more retransmissions based on the second indication and the third indication of the power ramp steps and the repetition pattern until a successfully received transmission. For example, referring to FIGs. 7 and 11, the ambient IoT device 1104 may select, at 1114, a frequency resource (and an associated transmission power) for an initial transmission of a preamble 1116 for a random access procedure based on a DL signal strength measured at 1112 and, in some aspects, based on an amplification capability of the ambient IoT device 1104. The ambient IoT device 1104 may further maintain a retransmission counter at 1118 and may transmit one or more preamble retransmissions 1120 based on the retransmission configuration 1107 (e.g., the power ramp configuration 1108 and the repetition pattern 1109) . The one or more preamble retransmissions 1120 may be based on one of the power and repetition patterns described above in relation to FIGs. 8, 9, and 10.

FIG. 14 is a flowchart 1400 of a method of wireless communication. The method may be performed by a network device such as a base station (e.g., the base station 102, 602, 1102; the RFID reader 402; the interrogator 502; the network entity 1602, 1702) . At 1402, the network device may output a first indication of a plurality of resources for a preamble transmission from at least one active backscatter device and a corresponding plurality of downlink signal strength ranges. For example, 1402 may be performed by CU processor (s) 1712, DU processor (s) 1732, RU processor (s) 1742, transceiver (s) 1746, antenna (s) 1780, and/or an active ambient IoT device initial access configuration component 199 of FIG. 17. In some aspects, for at least a first downlink signal strength range, the corresponding resources include multiple sets of resources, where each set of resources is associated with a range of amplification capabilities of backscatter (or ambient IoT) devices. For example, referring to FIGs. 7 and 11, the base station 1102 may transmit resource configuration 1106 indicating one of the configurations illustrated in diagram 700, diagram 740, or diagram 770.

At 1404, the network device may output a second indication for a set of power ramp steps associated with the plurality of resources. In some aspects, the set of power ramp steps may include different power ramp steps for different energy statuses (e.g., amounts of energy or energy harvesting to consumption ratios) where for a lower stored energy a power ramp step may be larger to increase a likelihood of success in a smaller number of repetitions and/or retransmissions. For example, 1404 may be performed by CU processor (s) 1712, DU processor (s) 1732, RU processor (s) 1742, transceiver (s) 1746, antenna (s) 1780, and/or an active ambient IoT device initial access configuration component 199 of FIG. 17. In some aspects, the second indication for the set of power ramp steps may indicate a power ramp step that applies to a plurality of different classes of backscatter devices with different capabilities. The second indication for the set of power ramp steps, in some aspects, may indicate a power ramp step for each of a plurality of different classes of backscatter (or ambient IoT) devices with different capabilities, where the power ramp step may be different for each of the plurality of different classes of backscatter devices. For example, referring to FIGs. 8, 9, 10, and 11, the base station 1102 may transmit retransmission configuration 1107 (and more specifically, power ramp configuration 1108) indicating a set of power ramp steps according to one of the power and repetition patterns illustrated in FIGs. 8, 9, and 10.

In some aspects, the network device may output a third indication for a repetition pattern associated with the preamble transmission. Outputting the third indication, in some aspects, may include outputting a number of repetitions associated with at least one of a first transmission or a retransmission. In some aspects, the third indication may include or be associated with a fourth indication of a maximum number of retransmissions. The second and third indication, in some aspects, may be included in a power and repetition pattern indication and/or configuration. In some aspects, each preamble transmission is associated with one or more repetitions and the repetition pattern (alternatively referred to as a power and repetition pattern) may indicate increasing, after a failure of each previous preamble transmission and based on the second indication, a power associated with a subsequent preamble transmission until reaching a maximum power. The repetition pattern, in some aspects, may indicate increasing, after the failure of each previous preamble transmission and based on the second indication, a number of repetitions associated with the subsequent preamble transmission and the power associated with the subsequent preamble transmission until reaching a maximum number of repetitions and the maximum power. In some aspects, the repetition pattern may indicate increasing, after the failure of each previous preamble transmission and based on the second indication, the power associated with a set of subsequent preamble transmissions while maintaining a first number of repetitions associated with the set of subsequent preamble transmissions and, upon using the maximum power for a subsequent preamble transmission in the set of subsequent preamble transmissions, increasing the number of repetitions associated with one or more subsequent preamble transmissions at the maximum power until reaching the maximum number of repetitions.

The repetition pattern in some aspects, may indicate increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions. In some aspects, the repetition pattern may indicate increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the set of subsequent preamble transmissions while maintaining a first power associated with the set of subsequent preamble transmissions and, upon using the maximum number of repetitions for the subsequent preamble transmission in the set of subsequent preamble transmissions and based on the second indication, increasing the power associated with one or more subsequent preamble transmissions at the maximum number of repetitions until reaching the maximum power. The repetition pattern in some aspects, may indicate increasing, after a failure of a first configured number of previous preamble transmissions, the number of repetitions associated with the set of subsequent preamble transmissions until reaching the maximum number of repetitions and increasing, after a failure of a second configured number of previous preamble transmissions and based on the second indication, the power associated with the subsequent preamble transmission until reaching the maximum power. In some aspects, the repetition pattern may indicate iteratively, (1) beginning from the first number of repetitions associated with the preamble transmission at a current power, increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions, and, after the failure of a preamble transmission associated with the maximum number of repetitions, (2) increasing the current power based on the second indication until the maximum power is reached. For example, referring to FIGs. 8, 9, 10, and 11, the base station 1102 may transmit retransmission configuration 1107 (and more specifically, repetition pattern 1109) indicating a repetition pattern according to one of the power and repetition patterns illustrated in FIGs. 8, 9, and 10.

At 1408, the network device may receive at least one random access message associated with the at least one active backscatter device based on the first indication and the second indication. For example, 1408 may be performed by CU processor (s) 1712, DU processor (s) 1732, RU processor (s) 1742, transceiver (s) 1746, antenna (s) 1780, and/or an active ambient IoT device initial access configuration component 199 of FIG. 17. In some aspects, receiving the at least one random access message may include unsuccessfully receiving an initial transmission of a preamble and one or more retransmissions based on the second indication and the third indication of the power ramp steps and the repetition pattern until a successfully received transmission. For example, referring to FIGs. 8, 9, 10, and 11, the base station 1102 may receive one or more of an initial transmission of preamble 1116 or the preamble retransmissions 1120 based on the retransmission configuration 1107 (e.g., the power ramp configuration 1108 and the repetition pattern 1109) . The one or more preamble retransmissions 1120 may be based on one of the power and repetition patterns described above in relation to FIGs. 8, 9, and 10.

FIG. 15 is a flowchart 1500 of a method of wireless communication. The method may be performed by a network device such as a base station (e.g., the base station 102, 602, 1102; the RFID reader 402; the interrogator 502; the network entity 1602, 1702) . At 1502, the network device may output a first indication of a plurality of resources for a preamble transmission from at least one active backscatter device and a corresponding plurality of downlink signal strength ranges. For example, 1502 may be performed by CU processor (s) 1712, DU processor (s) 1732, RU processor (s) 1742, transceiver (s) 1746, antenna (s) 1780, and/or an active ambient IoT device initial access configuration component 199 of FIG. 17. In some aspects, for at least a first downlink signal strength range, the corresponding resources include multiple sets of resources, where each set of resources is associated with a range of amplification capabilities of backscatter (or ambient IoT) devices. For example, referring to FIGs. 7 and 11, the base station 1102 may transmit resource configuration 1106 indicating one of the configurations illustrated in diagram 700, diagram 740, or diagram 770.

At 1504, the network device may output a second indication for a set of power ramp steps associated with the plurality of resources. In some aspects, the set of power ramp steps may include different power ramp steps for different energy statuses (e.g., amounts of energy or energy harvesting to consumption ratios) where for a lower stored energy a power ramp step may be larger to increase a likelihood of success in a smaller number of repetitions and/or retransmissions. For example, 1504 may be performed by CU processor (s) 1712, DU processor (s) 1732, RU processor (s) 1742, transceiver (s) 1746, antenna (s) 1780, and/or an active ambient IoT device initial access configuration component 199 of FIG. 17. In some aspects, the second indication for the set of power ramp steps may indicate a power ramp step that applies to a plurality of different classes of backscatter devices with different capabilities. The second indication for the set of power ramp steps, in some aspects, may indicate a power ramp step for each of a plurality of different classes of backscatter (or ambient IoT) devices with different capabilities, where the power ramp step may be different for each of the plurality of different classes of backscatter devices. For example, referring to FIGs. 8, 9, 10, and 11, the base station 1102 may transmit retransmission configuration 1107 (and more specifically, power ramp configuration 1108) indicating a set of power ramp steps according to one of the power and repetition patterns illustrated in FIGs. 8, 9, and 10.

At 1506, the network device may output a third indication for a repetition pattern associated with the preamble transmission. Outputting the third indication, in some aspects, may include outputting a number of repetitions associated with at least one of a first transmission or a retransmission. In some aspects, the third indication may include or be associated with a fourth indication of a maximum number of retransmissions. The second and third indication, in some aspects, may be included in a power and repetition pattern indication and/or configuration. For example, 1506 may be performed by CU processor (s) 1712, DU processor (s) 1732, RU processor (s) 1742, transceiver (s) 1746, antenna (s) 1780, and/or an active ambient IoT device initial access configuration component 199 of FIG. 17. In some aspects, each preamble transmission is associated with one or more repetitions and the repetition pattern (alternatively referred to as a power and repetition pattern) may indicate increasing, after a failure of each previous preamble transmission and based on the second indication, a power associated with a subsequent preamble transmission until reaching a maximum power. The repetition pattern, in some aspects, may indicate increasing, after the failure of each previous preamble transmission and based on the second indication, a number of repetitions associated with the subsequent preamble transmission and the power associated with the subsequent preamble transmission until reaching a maximum number of repetitions and the maximum power. In some aspects, the repetition pattern may indicate increasing, after the failure of each previous preamble transmission and based on the second indication, the power associated with a set of subsequent preamble transmissions while maintaining a first number of repetitions associated with the set of subsequent preamble transmissions and, upon using the maximum power for a subsequent preamble transmission in the set of subsequent preamble transmissions, increasing the number of repetitions associated with one or more subsequent preamble transmissions at the maximum power until reaching the maximum number of repetitions.

At 1508, the network device may receive at least one random access message associated with the at least one active backscatter device based on the first indication and the second indication. For example, 1508 may be performed by CU processor (s) 1712, DU processor (s) 1732, RU processor (s) 1742, transceiver (s) 1746, antenna (s) 1780, and/or an active ambient IoT device initial access configuration component 199 of FIG. 17. In some aspects, receiving the at least one random access message may include unsuccessfully receiving an initial transmission of a preamble and one or more retransmissions based on the second indication and the third indication of the power ramp steps and the repetition pattern until a successfully received transmission. For example, referring to FIGs. 8, 9, 10, and 11, the base station 1102 may receive one or more of an initial transmission of preamble 1116 or the preamble retransmissions 1120 based on the retransmission configuration 1107 (e.g., the power ramp configuration 1108 and the repetition pattern 1109) . The one or more preamble retransmissions 1120 may be based on one of the power and repetition patterns described above in relation to FIGs. 8, 9, and 10.

FIG. 16 is a diagram 1600 illustrating an example of a hardware implementation for an apparatus 1604. The apparatus 1604 may be a UE, a component of a UE, or may implement UE functionality. In some aspects, the apparatus 1604 may include at least one cellular baseband processor 1624 (also referred to as a modem) coupled to one or more transceivers 1622 (e.g., cellular RF transceiver) . The cellular baseband processor (s) 1624 may include at least one on-chip memory 1624'. In some aspects, the apparatus 1604 may further include one or more subscriber identity modules (SIM) cards 1620 and at least one application processor 1606 coupled to a secure digital (SD) card 1608 and a screen 1610. The application processor (s) 1606 may include on-chip memory 1606'. In some aspects, the apparatus 1604 may further include a Bluetooth module 1612, a WLAN module 1614, an SPS module 1616 (e.g., GNSS module) , one or more sensor modules 1618 (e.g., barometric pressure sensor /altimeter; motion sensor such as inertial measurement unit (IMU) , gyroscope, and/or accelerometer (s) ; light detection and ranging (LIDAR) , radio assisted detection and ranging (RADAR) , sound navigation and ranging (SONAR) , magnetometer, audio and/or other technologies used for positioning) , additional memory modules 1626, a power supply 1630, and/or a camera 1632. The Bluetooth module 1612, the WLAN module 1614, and the SPS module 1616 may include an on-chip transceiver (TRX) (or in some cases, just a receiver (RX) ) . The Bluetooth module 1612, the WLAN module 1614, and the SPS module 1616 may include their own dedicated antennas and/or utilize one or more antennas 1680 for communication. The cellular baseband processor (s) 1624 communicates through the transceiver (s) 1622 via the one or more antennas 1680 with the UE 104 and/or with an RU associated with a network entity 1602. The cellular baseband processor (s) 1624 and the application processor (s) 1606 may each include a computer-readable medium /memory 1624', 1606', respectively. The additional memory modules 1626 may also be considered a computer-readable medium /memory. Each computer-readable medium /memory 1624', 1606', 1626 may be non-transitory. The cellular baseband processor (s) 1624 and the application processor (s) 1606 are each responsible for general processing, including the execution of software stored on the computer-readable medium /memory. The software, when executed by the cellular baseband processor (s) 1624 /application processor (s) 1606, causes the cellular baseband processor (s) 1624 /application processor (s) 1606 to perform the various functions described supra. The computer-readable medium /memory may also be used for storing data that is manipulated by the cellular baseband processor (s) 1624 /application processor (s) 1606 when executing software. The cellular baseband processor (s) 1624 /application processor (s) 1606 may be a component of the UE 350 and may include the at least one memory 360 and/or at least one of the TX processor 368, the RX processor 356, and the controller/processor 359. In one configuration, the apparatus 1604 may be at least one processor chip (modem and/or application) and include just the cellular baseband processor (s) 1624 and/or the application processor (s) 1606, and in another configuration, the apparatus 1604 may be the entire UE (e.g., see UE 350 of FIG. 3) and include the additional modules of the apparatus 1604.

As discussed supra, the active ambient IoT device initial access component 198 may be configured to obtain a first indication of a plurality of resources for a preamble transmission from the active backscatter device and a corresponding plurality of downlink signal strength ranges, obtain a second indication for a set of power ramp steps associated with the plurality of resources, and perform a random access procedure associated with a network device based on the first indication and the second indication. The active ambient IoT device initial access component 198 may be within the cellular baseband processor (s) 1624, the application processor (s) 1606, or both the cellular baseband processor (s) 1624 and the application processor (s) 1606. The active ambient IoT device initial access component 198 may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by one or more processors configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by one or more processors, or some combination thereof. When multiple processors are implemented, the multiple processors may perform the stated processes/algorithm individually or in combination. As shown, the apparatus 1604 may include a variety of components configured for various functions. In one configuration, the apparatus 1604, and in particular the cellular baseband processor (s) 1624 and/or the application processor (s) 1606, may include means for obtaining a first indication of a plurality of resources for a preamble transmission from the active backscatter device and a corresponding plurality of downlink signal strength ranges. The apparatus 1604, and in particular the cellular baseband processor (s) 1624 and/or the application processor (s) 1606, may include means for obtaining a second indication for a set of power ramp steps associated with the plurality of resources. The apparatus 1604, and in particular the cellular baseband processor (s) 1624 and/or the application processor (s) 1606, may include means for performing a random access procedure associated with a network device based on the first indication and the second indication. The apparatus 1604, and in particular the cellular baseband processor (s) 1624 and/or the application processor (s) 1606, may include means for selecting a resource to use for the preamble transmission from the plurality of resources based on a downlink signal strength associated with the network device. The apparatus 1604, and in particular the cellular baseband processor (s) 1624 and/or the application processor (s) 1606, may include means for obtaining a third indication of a number of repetitions associated with at least one of a first transmission or a retransmission. The apparatus 1604, and in particular the cellular baseband processor (s) 1624 and/or the application processor (s) 1606, may include means for obtaining a fourth indication of a maximum number of retransmissions. The apparatus 1604, and in particular the cellular baseband processor (s) 1624 and/or the application processor (s) 1606, may include means for maintaining a retransmission counter. The apparatus 1604, and in particular the cellular baseband processor (s) 1624 and/or the application processor (s) 1606, may include means for obtaining a third indication for a repetition pattern associated with the preamble transmission. The apparatus 1604 may further include means for performing any of the aspects described in connection with the flowcharts in FIGs. 12 or 13, and/or performed by the ambient IoT device in the communication flow of FIG. 11. The means may be the active ambient IoT device initial access component 198 of the apparatus 1604 configured to perform the functions recited by the means. As described supra, the apparatus 1604 may include the TX processor 368, the RX processor 356, and the controller/processor 359. As such, in one configuration, the means may be the TX processor 368, the RX processor 356, and/or the controller/processor 359 configured to perform the functions recited by the means.

FIG. 17 is a diagram 1700 illustrating an example of a hardware implementation for a network entity 1702. The network entity 1702 may be a BS, a component of a BS, or may implement BS functionality. The network entity 1702 may include at least one of a CU 1710, a DU 1730, or an RU 1740. For example, depending on the layer functionality handled by the active ambient IoT device initial access configuration component 199, the network entity 1702 may include the CU 1710; both the CU 1710 and the DU 1730; each of the CU 1710, the DU 1730, and the RU 1740; the DU 1730; both the DU 1730 and the RU 1740; or the RU 1740. The CU 1710 may include at least one CU processor 1712. The CU processor (s) 1712 may include on-chip memory 1712'. In some aspects, the CU 1710 may further include additional memory modules 1714 and a communications interface 1718. The CU 1710 communicates with the DU 1730 through a midhaul link, such as an F1 interface. The DU 1730 may include at least one DU processor 1732. The DU processor (s) 1732 may include on-chip memory 1732'. In some aspects, the DU 1730 may further include additional memory modules 1734 and a communications interface 1738. The DU 1730 communicates with the RU 1740 through a fronthaul link. The RU 1740 may include at least one RU processor 1742. The RU processor (s) 1742 may include on-chip memory 1742'. In some aspects, the RU 1740 may further include additional memory modules 1744, one or more transceivers 1746, one or more antennas 1780, and a communications interface 1748. The RU 1740 communicates with the UE 104. The on-chip memory 1712', 1732', 1742' and the additional memory modules 1714, 1734, 1744 may each be considered a computer-readable medium /memory. Each computer-readable medium /memory may be non-transitory. Each of the processors 1712, 1732, 1742 is responsible for general processing, including the execution of software stored on the computer-readable medium /memory. The software, when executed by the corresponding processor (s) causes the processor (s) to perform the various functions described supra. The computer-readable medium /memory may also be used for storing data that is manipulated by the processor (s) when executing software.

As discussed supra, the active ambient IoT device initial access configuration component 199 may be configured to output a first indication of a plurality of resources for a preamble transmission from at least one active backscatter device and a corresponding plurality of downlink signal strength ranges, output a second indication for a set of power ramp steps associated with the plurality of resources, and receive at least one random access message associated with the at least one active backscatter device based on the first indication and the second indication. The active ambient IoT device initial access configuration component 199 may be within one or more processors of one or more of the CU 1710, DU 1730, and the RU 1740. The active ambient IoT device initial access configuration component 199 may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by one or more processors configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by one or more processors, or some combination thereof. When multiple processors are implemented, the multiple processors may perform the stated processes/algorithm individually or in combination. The network entity 1702 may include a variety of components configured for various functions. In one configuration, the network entity 1702 may include means for outputting a first indication of a plurality of resources for a preamble transmission from at least one active backscatter device and a corresponding plurality of downlink signal strength ranges. The network entity 1702, in some aspects, may include means for outputting a second indication for a set of power ramp steps associated with the plurality of resources. The network entity 1702, in some aspects, may include means for receiving at least one random access message associated with the at least one active backscatter device based on the first indication and the second indication. The network entity 1702, in some aspects, may include means for outputting a third indication of a number of repetitions associated with at least one of a first transmission or a retransmission. The network entity 1702, in some aspects, may include means for outputting a fourth indication of a maximum number of retransmissions. The network entity 1702, in some aspects, may include means for outputting a third indication for a repetition pattern associated with the preamble transmission. The apparatus 1702 may further include means for performing any of the aspects described in connection with the flowcharts in FIGs. 14 or 15, and/or performed by the base station in the communication flow of FIG. 11. The means may be the active ambient IoT device initial access configuration component 199 of the network entity 1702 configured to perform the functions recited by the means. As described supra, the network entity 1702 may include the TX processor 316, the RX processor 370, and the controller/processor 375. As such, in one configuration, the means may be the TX processor 316, the RX processor 370, and/or the controller/processor 375 configured to perform the functions recited by the means.

FIG. 18 is a diagram 1800 illustrating an example of a hardware implementation for an apparatus 1804. The apparatus may be an energy harvesting device (e.g., a backscatter device, a tag, etc. ) . The apparatus may include aspects described in connection with FIG. 4, among other examples. In some aspects, the apparatus 1804 may be a UE, a component of a UE, or may implement UE functionality, similar to the apparatus described in connection with FIG. 16. In some aspects, the apparatus 1804 may include at least one processor 1824 coupled to one or more antennas 1880. The processor (s) 1824 may provide an energy harvesting component, such as described in connection with FIG. 4. The processor (s) 1824 may include memory 1824'. In some aspects, the apparatus 1804 may further include an SPS module 1816 (e.g., GNSS module) , one or more sensor modules 1818 (e.g., barometric pressure sensor /altimeter; motion sensor such as IMU, gyroscope, and/or accelerometer (s) ; LIDAR, RADAR, SONAR, magnetometer, audio and/or other technologies used for positioning) , additional memory modules 1826, and/or a power supply or storage device 1830. The SPS module 1816 may include an on-chip TRX (or in some cases, just a RX) . The SPS module 1816 may include its own dedicated antennas and/or utilize the antennas 1880 for communication. The processor (s) 1824 receives a signal, such as a backscatter signal, and harvest energy from the receive signal. The processor (s) 1824 receives the signal via the one or more antennas 1880 from the UE 104, reader 1832 and/or with an RU associated with a network entity 1802. The processor (s) 1824 may include a computer-readable medium /memory 1824'. The additional memory modules 1826 may also be considered a computer-readable medium /memory. Each computer-readable medium /memory 1824', 1826 may be non-transitory. The processor (s) 1824 is responsible for general processing, including the execution of software stored on the computer-readable medium /memory. The software, when executed by the processor 1824, causes the processor (s) 1824 to perform the various functions described supra. The computer-readable medium /memory may also be used for storing data that is manipulated by the processor (s) 1824 when executing software. In some aspects, the processor (s) 1824 may be a component of the UE 350, or other energy harvesting device, and may include the memory 360 and/or at least one of the TX processor 368, the RX processor 356, and the controller/processor 359. In one configuration, the apparatus 1804 may be an energy harvesting device. In other configurations, the apparatus 1804 may be an energy harvesting component of a device.

As discussed supra, the active ambient IoT device initial access component 198 that may be configured to obtain a first indication of a plurality of resources for a preamble transmission from the active backscatter device and a corresponding plurality of downlink signal strength ranges, obtain a second indication for a set of power ramp steps associated with the plurality of resources, and perform a random access procedure associated with a network device based on the first indication and the second indication. The active ambient IoT device initial access component 198 may be within the processor (s) 1824. The active ambient IoT device initial access component 198 may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by one or more processors configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by one or more processors, or some combination thereof. As shown, the apparatus 1804 may include a variety of components configured for various functions. In one configuration, the apparatus 1804, and in particular the processor (s) 1824, may include means for obtaining a first indication of a plurality of resources for a preamble transmission from the active backscatter device and a corresponding plurality of downlink signal strength ranges. The apparatus 1804, and in particular the processor (s) 1824, may include means for obtaining a second indication for a set of power ramp steps associated with the plurality of resources. The apparatus 1804, and in particular the processor (s) 1824, may include means for performing a random access procedure associated with a network device based on the first indication and the second indication. The apparatus 1804, and in particular the processor (s) 1824, may include means for selecting a resource to use for the preamble transmission from the plurality of resources based on a downlink signal strength associated with the network device. The apparatus 1804, and in particular the processor (s) 1824, may include means for obtaining a third indication of a number of repetitions associated with at least one of a first transmission or a retransmission. The apparatus 1804, and in particular the processor (s) 1824, may include means for obtaining a fourth indication of a maximum number of retransmissions. The apparatus 1804, and in particular the processor (s) 1824, may include means for maintaining a retransmission counter. The apparatus 1804, and in particular the processor (s) 1824, may include means for obtaining a third indication for a repetition pattern associated with the preamble transmission. The means may be the active ambient IoT device initial access component 198 of the apparatus 1804. The apparatus 1804 may further include means for performing any of the aspects described in connection with the flowcharts in FIGs. 12 or 13, and/or performed by the ambient IoT device in the communication flow of FIG. 11. As described supra, in some aspects, the apparatus 1804 may include the TX processor 368, the RX processor 356, and the controller/processor 359. As such, in one configuration, the means may be the TX processor 368, the RX processor 356, and/or the controller/processor 359 configured to perform the functions recited by the means. In some aspects, the means may include the processor (s) 1824 and/or the antennas 1880.

It is understood that the specific order or hierarchy of blocks in the processes /flowcharts disclosed is an illustration of example approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes /flowcharts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in a sample order, and are not limited to the specific order or hierarchy presented.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not limited to the aspects described herein, but are to be accorded the full scope consistent with the language claims. Reference to an element in the singular does not mean “one and only one” unless specifically so stated, but rather “one or more. ” Terms such as “if, ” “when, ” and “while” do not imply an immediate temporal relationship or reaction. That is, these phrases, e.g., “when, ” do not imply an immediate action in response to or during the occurrence of an action, but simply imply that if a condition is met then an action will occur, but without requiring a specific or immediate time constraint for the action to occur. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. Sets should be interpreted as a set of elements where the elements number one or more. Accordingly, for a set of X, X would include one or more elements. When at least one processor is configured to perform a set of functions, the at least one processor, individually or in any combination, is configured to perform the set of functions. Accordingly, each processor of the at least one processor may be configured to perform a particular subset of the set of functions, where the subset is the full set, a proper subset of the set, or an empty subset of the set. A processor may be referred to as processor circuitry. A memory /memory module may be referred to as memory circuitry. If a first apparatus receives data from or transmits data to a second apparatus, the data may be received/transmitted directly between the first and second apparatuses, or indirectly between the first and second apparatuses through a set of apparatuses. A device configured to “output” data, such as a transmission, signal, or message, may transmit the data, for example with a transceiver, or may send the data to a device that transmits the data. A device configured to “obtain” data, such as a transmission, signal, or message, may receive, for example with a transceiver, or may obtain the data from a device that receives the data. Information stored in a memory includes instructions and/or data. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are encompassed by the claims. Moreover, nothing disclosed herein is dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. The words “module, ” “mechanism, ” “element, ” “device, ” and the like may not be a substitute for the word “means. ” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for. ”

As used herein, the phrase “based on” shall not be construed as a reference to a closed set of information, one or more conditions, one or more factors, or the like. In other words, the phrase “based on A” (where “A” may be information, a condition, a factor, or the like) shall be construed as “based at least on A” unless specifically recited differently.

The following aspects are illustrative only and may be combined with other aspects or teachings described herein, without limitation.

Aspect 1 is a method of wireless communication for an active backscatter device, comprising: obtaining a first indication of a plurality of resources for a preamble transmission from the active backscatter device and a corresponding plurality of downlink signal strength ranges; obtaining a second indication for a set of power ramp steps associated with the plurality of resources; and performing a random access procedure associated with a network device based on the first indication and the second indication.

Aspect 2 is the method of aspect 1, wherein the first indication is based on a configuration of the plurality of resources or obtaining the first indication includes receiving the first indication from the network device.

Aspect 3 is the method of any of aspects 1 and 2, wherein, for at least a first downlink signal strength range, corresponding resources comprise multiple sets of resources, wherein each set of resources is associated with a range of amplification capabilities of backscatter devices.

Aspect 4 is the method of any of aspects 1 to 3, wherein performing the random access procedure based on the first indication comprises: selecting a resource to use for the preamble transmission from the plurality of resources based on a downlink signal strength associated with the network device.

Aspect 5 is the method of aspect 4, wherein selecting the resource to use for the preamble transmission is further based on an amplification capability of the active backscatter device.

Aspect 6 is the method of any of aspects 1 to 5, further comprising: obtaining a third indication of a number of repetitions associated with at least one of a first transmission or a retransmission.

Aspect 7 is the method of aspect 6, further comprising: obtaining a fourth indication of a maximum number of retransmissions.

Aspect 8 is the method of any of aspects 6 and 7, further comprising: maintaining a retransmission counter.

Aspect 9 is the method of any of aspects 1 to 8, wherein the second indication for the set of power ramp steps indicates a power ramp step that applies to a plurality of different classes of backscatter devices with different capabilities.

Aspect 10 is the method of any of aspects 1 to 9, wherein the second indication for the set of power ramp steps indicates a separate power ramp step for each preamble transmission.

Aspect 11 is the method of any of aspects 1 to 11, wherein the second indication for the set of power ramp steps indicates a first set of power ramp steps associated with a first energy status of a backscatter device and a second set of power ramp steps associated with a second energy status of the backscatter device.

Aspect 12 is the method of any of aspects 1 to 11, further comprising: obtaining a third indication for a repetition pattern associated with the preamble transmission, wherein each preamble transmission is associated with one or more repetitions and the repetition pattern comprises one of: increasing, after a failure of each previous preamble transmission and based on the second indication, a power associated with a subsequent preamble transmission until reaching a maximum power; increasing, after the failure of each previous preamble transmission and based on the second indication, a number of repetitions associated with the subsequent preamble transmission and the power associated with the subsequent preamble transmission until reaching a maximum number of repetitions and the maximum power; increasing, after the failure of each previous preamble transmission and based on the second indication, the power associated with a set of subsequent preamble transmissions while maintaining a first number of repetitions associated with the set of subsequent preamble transmissions and, upon using the maximum power for a subsequent preamble transmission in the set of subsequent preamble transmissions, increasing the number of repetitions associated with one or more subsequent preamble transmissions at the maximum power until reaching the maximum number of repetitions; increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions; increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the set of subsequent preamble transmissions while maintaining a first power associated with the set of subsequent preamble transmissions and, upon using the maximum number of repetitions for the subsequent preamble transmission in the set of subsequent preamble transmissions and based on the second indication, increasing the power associated with one or more subsequent preamble transmissions at the maximum number of repetitions until reaching the maximum power; increasing, after a failure of a first configured number of previous preamble transmissions, the number of repetitions associated with the set of subsequent preamble transmissions until reaching the maximum number of repetitions and increasing, after a failure of a second configured number of previous preamble transmissions and based on the second indication, the power associated with the subsequent preamble transmission until reaching the maximum power; or iteratively, (1) beginning from the first number of repetitions associated with the preamble transmission at a current power, increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions, and, after the failure of a preamble transmission associated with the maximum number of repetitions, (2) increasing the current power based on the second indication until the maximum power is reached.

Aspect 13 is a method of wireless communication for a network device, comprising: outputting a first indication of a plurality of resources for a preamble transmission from at least one active backscatter device and a corresponding plurality of downlink signal strength ranges; outputting a second indication for a set of power ramp steps associated with the plurality of resources; and receiving at least one random access message associated with the at least one active backscatter device based on the first indication and the second indication.

Aspect 14 is the method of aspect 13, wherein, for at least a first downlink signal strength range, corresponding resources comprise multiple sets of resources, wherein each set of resources is associated with a range of amplification capabilities of backscatter devices.

Aspect 15 is the method of any of aspects 13 and 14, further comprising: outputting a third indication of a number of repetitions associated with at least one of a first transmission or a retransmission.

Aspect 16 is the method of aspect 15, further comprising: outputting a fourth indication of a maximum number of retransmissions.

Aspect 17 is the method of any of aspects 13 to 16, wherein the second indication for the set of power ramp steps indicates a power ramp step that applies to a plurality of different classes of backscatter devices with different capabilities.

Aspect 18 is the method of any of aspects 13 to 17, wherein the second indication for the set of power ramp steps indicates a separate power ramp step for each preamble transmission.

Aspect 19 is the method of any of aspects 13 to 18, wherein the second indication for the set of power ramp steps indicates a first set of power ramp steps associated with a first energy status of a backscatter device and a second set of power ramp steps associated with a second energy status of the backscatter device.

Aspect 20 is the method of any of aspects 13 to 19, further comprising: outputting a third indication for a repetition pattern associated with the preamble transmission, wherein each preamble transmission is associated with one or more repetitions and the repetition pattern comprises one of: increasing, after a failure of each previous preamble transmission and based on the second indication, a power associated with a subsequent preamble transmission until reaching a maximum power; increasing, after the failure of each previous preamble transmission and based on the second indication, a number of repetitions associated with the subsequent preamble transmission and the power associated with the subsequent preamble transmission until reaching a maximum number of repetitions and the maximum power; increasing, after the failure of each previous preamble transmission and based on the second indication, the power associated with a set of subsequent preamble transmissions while maintaining a first number of repetitions associated with the set of subsequent preamble transmissions and, upon using the maximum power for a subsequent preamble transmission in the set of subsequent preamble transmissions, increasing the number of repetitions associated with one or more subsequent preamble transmissions at the maximum power until reaching the maximum number of repetitions; increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions; increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the set of subsequent preamble transmissions while maintaining a first power associated with the set of subsequent preamble transmissions and, upon using the maximum number of repetitions for the subsequent preamble transmission in the set of subsequent preamble transmissions and based on the second indication, increasing the power associated with one or more subsequent preamble transmissions at the maximum number of repetitions until reaching the maximum power; increasing, after a failure of a first configured number of previous preamble transmissions, the number of repetitions associated with the set of subsequent preamble transmissions until reaching the maximum number of repetitions and increasing, after a failure of a second configured number of previous preamble transmissions and based on the second indication, the power associated with the subsequent preamble transmission until reaching the maximum power; or iteratively, (1) beginning from the first number of repetitions associated with the preamble transmission at a current power, increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions, and, after the failure of a preamble transmission associated with the maximum number of repetitions, (2) increasing the current power based on the second indication until the maximum power is reached.

Aspect 21 is an apparatus for wireless communication at a device including a memory and at least one processor coupled to the memory and, based at least in part on information stored in the memory, the at least one processor is configured to implement any of aspects 1 to 12.

Aspect 22 is the apparatus of aspect 21, further including a transceiver or an antenna coupled to the at least one processor.

Aspect 23 is an apparatus for wireless communication at a device including means for implementing any of aspects 1 to 12.

Aspect 24 is a computer-readable medium (e.g., a non-transitory computer-readable medium) storing computer executable code, where the code when executed by a processor causes the processor to implement any of aspects 1 to 12.

Aspect 25 is an apparatus for wireless communication at a device including a memory and at least one processor coupled to the memory and, based at least in part on information stored in the memory, the at least one processor is configured to implement any of aspects 13 to 20.

Aspect 26 is the apparatus of aspect 25, further including a transceiver or an antenna coupled to the at least one processor.

Aspect 27 is an apparatus for wireless communication at a device including means for implementing any of aspects 13 to 20.

Aspect 28 is a computer-readable medium (e.g., a non-transitory computer-readable medium) storing computer executable code, where the code when executed by a processor causes the processor to implement any of aspects 13 to 20.

Claims

An apparatus for wireless communication at a type C ambient-IoT device, comprising:

at least one memory; and

at least one processor coupled to the at least one memory and, based at least in part on stored information that is stored in the at least one memory, the at least one processor, individually or in any combination, is configured to:

obtain a first indication of a plurality of resources for a preamble transmission from the type C ambient-IoT device and a corresponding plurality of downlink signal strength ranges;

obtain a second indication for a set of power ramp steps associated with the plurality of resources; and

perform a random access procedure associated with a network device based on the first indication and the second indication.
The apparatus of claim 1, wherein the first indication is based on a configuration of the plurality of resources or wherein to obtain the first indication, the at least one processor, individually or in any combination, is configured to receive the first indication from the network device.
The apparatus of claim 1, wherein, for at least a first downlink signal strength range, corresponding resources comprise multiple sets of resources, wherein each set of resources is associated with a range of amplification capabilities of backscatter devices.
The apparatus of claim 1, wherein to perform the random access procedure based on the first indication, the at least one processor, individually or in any combination, is further configured to:

select a resource to use for the preamble transmission from the plurality of resources based on a downlink signal strength associated with the network device.
The apparatus of claim 4, wherein to select the resource to use for the preamble transmission, the at least one processor, individually or in any combination, is further configured to select the resource based on an amplification capability of the type C ambient-IoT device.
The apparatus of claim 1, wherein the at least one processor, individually or in any combination, is further configured to:

obtain a third indication of a number of repetitions associated with at least one of a first transmission or a retransmission.
The apparatus of claim 6, wherein the at least one processor, individually or in any combination, is further configured to:

obtain a fourth indication of a maximum number of retransmissions.
The apparatus of claim 6, wherein the at least one processor, individually or in any combination, is further configured to:

maintain a retransmission counter.
The apparatus of claim 1, wherein the second indication for the set of power ramp steps indicates a power ramp step that applies to a plurality of different classes of backscatter devices with different capabilities.
The apparatus of claim 1, wherein the second indication for the set of power ramp steps indicates a separate power ramp step for each preamble transmission.
The apparatus of claim 1, wherein the second indication for the set of power ramp steps indicates a first set of power ramp steps associated with a first energy status of a backscatter device and a second set of power ramp steps associated with a second energy status of the backscatter device.
The apparatus of claim 1, wherein the at least one processor, individually or in any combination, is further configured to:

obtain a third indication for a repetition pattern associated with the preamble transmission, wherein each preamble transmission is associated with one or more repetitions and the repetition pattern comprises one of:

increasing, after a failure of each previous preamble transmission and based on the second indication, a power associated with a subsequent preamble transmission until reaching a maximum power;

increasing, after the failure of each previous preamble transmission and based on the second indication, a number of repetitions associated with the subsequent preamble transmission and the power associated with the subsequent preamble transmission until reaching a maximum number of repetitions and the maximum power;

increasing, after the failure of each previous preamble transmission and based on the second indication, the power associated with a set of subsequent preamble transmissions while maintaining a first number of repetitions associated with the set of subsequent preamble transmissions and, upon using the maximum power for a subsequent preamble transmission in the set of subsequent preamble transmissions, increasing the number of repetitions associated with one or more subsequent preamble transmissions at the maximum power until reaching the maximum number of repetitions;

increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions;

increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the set of subsequent preamble transmissions while maintaining a first power associated with the set of subsequent preamble transmissions and, upon using the maximum number of repetitions for the subsequent preamble transmission in the set of subsequent preamble transmissions and based on the second indication, increasing the power associated with one or more subsequent preamble transmissions at the maximum number of repetitions until reaching the maximum power;

increasing, after a failure of a first configured number of previous preamble transmissions, the number of repetitions associated with the set of subsequent preamble transmissions until reaching the maximum number of repetitions and increasing, after a failure of a second configured number of previous preamble transmissions and based on the second indication, the power associated with the subsequent preamble transmission until reaching the maximum power; or

iteratively, (1) beginning from the first number of repetitions associated with the preamble transmission at a current power, increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions, and, after the failure of a preamble transmission associated with the maximum number of repetitions, (2) increasing the current power based on the second indication until the maximum power is reached.
An apparatus for wireless communication at a network device, comprising:

at least one memory; and

at least one processor coupled to the at least one memory and, based at least in part on stored information that is stored in the at least one memory, the at least one processor, individually or in any combination, is configured to:

output a first indication of a plurality of resources for a preamble transmission from at least one active backscatter device and a corresponding plurality of downlink signal strength ranges;

output a second indication for a set of power ramp steps associated with the plurality of resources; and

receive at least one random access message associated with the at least one active backscatter device based on the first indication and the second indication.
The apparatus of claim 13, wherein, for at least a first downlink signal strength range, corresponding resources comprise multiple sets of resources, wherein each set of resources is associated with a range of amplification capabilities of backscatter devices.
The apparatus of claim 13, wherein the at least one processor, individually or in any combination, is further configured to:

output a third indication of a number of repetitions associated with at least one of a first transmission or a retransmission.
The apparatus of claim 15, wherein the at least one processor, individually or in any combination, is further configured to:

output a fourth indication of a maximum number of retransmissions.
The apparatus of claim 13, wherein the second indication for the set of power ramp steps indicates a power ramp step that applies to a plurality of different classes of backscatter devices with different capabilities.
The apparatus of claim 13, wherein the second indication for the set of power ramp steps indicates a separate power ramp step for each preamble transmission.
The apparatus of claim 13, wherein the second indication for the set of power ramp steps indicates a first set of power ramp steps associated with a first energy status of a backscatter device and a second set of power ramp steps associated with a second energy status of the backscatter device.
The apparatus of claim 13, wherein the at least one processor, individually or in any combination, is further configured to:

output a third indication for a repetition pattern associated with the preamble transmission, wherein each preamble transmission is associated with one or more repetitions and the repetition pattern comprises one of:

increasing, after a failure of each previous preamble transmission and based on the second indication, a power associated with a subsequent preamble transmission until reaching a maximum power;

increasing, after the failure of each previous preamble transmission and based on the second indication, a number of repetitions associated with the subsequent preamble transmission and the power associated with the subsequent preamble transmission until reaching a maximum number of repetitions and the maximum power;

increasing, after the failure of each previous preamble transmission and based on the second indication, the power associated with a set of subsequent preamble transmissions while maintaining a first number of repetitions associated with the set of subsequent preamble transmissions and, upon using the maximum power for a subsequent preamble transmission in the set of subsequent preamble transmissions, increasing the number of repetitions associated with one or more subsequent preamble transmissions at the maximum power until reaching the maximum number of repetitions;

increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions;

increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the set of subsequent preamble transmissions while maintaining a first power associated with the set of subsequent preamble transmissions and, upon using the maximum number of repetitions for the subsequent preamble transmission in the set of subsequent preamble transmissions and based on the second indication, increasing the power associated with one or more subsequent preamble transmissions at the maximum number of repetitions until reaching the maximum power;

increasing, after a failure of a first configured number of previous preamble transmissions, the number of repetitions associated with the set of subsequent preamble transmissions until reaching the maximum number of repetitions and increasing, after a failure of a second configured number of previous preamble transmissions and based on the second indication, the power associated with the subsequent preamble transmission until reaching the maximum power; or

iteratively, (1) beginning from the first number of repetitions associated with the preamble transmission at a current power, increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions, and, after the failure of a preamble transmission associated with the maximum number of repetitions, (2) increasing the current power based on the second indication until the maximum power is reached.
A method of wireless communication for an type C ambient-IoT device, comprising:

obtaining a first indication of a plurality of resources for a preamble transmission from the type C ambient-IoT device and a corresponding plurality of downlink signal strength ranges;

obtaining a second indication for a set of power ramp steps associated with the plurality of resources; and

performing a random access procedure associated with a network device based on the first indication and the second indication.
The method of claim 21, wherein the first indication is based on a configuration of the plurality of resources or obtaining the first indication includes receiving the first indication from the network device.
The method of claim 21, wherein, for at least a first downlink signal strength range, corresponding resources comprise multiple sets of resources, wherein each set of resources is associated with a range of amplification capabilities of backscatter devices.
The method of claim 21, wherein performing the random access procedure based on the first indication comprises:

selecting a resource to use for the preamble transmission from the plurality of resources based on a downlink signal strength associated with the network device and an amplification capability of the type C ambient-IoT device.
The method of claim 21, wherein the second indication for the set of power ramp steps indicates a power ramp step that applies to a plurality of different classes of backscatter devices with different capabilities.
The method of claim 21, wherein the second indication for the set of power ramp steps indicates a first set of power ramp steps associated with a first energy status of a backscatter device and a second set of power ramp steps associated with a second energy status of the backscatter device.
The method of claim 21, further comprising:

obtaining a third indication for a repetition pattern associated with the preamble transmission, wherein each preamble transmission is associated with one or more repetitions and the repetition pattern comprises one of:

increasing, after a failure of each previous preamble transmission and based on the second indication, a power associated with a subsequent preamble transmission until reaching a maximum power;

increasing, after the failure of each previous preamble transmission and based on the second indication, a number of repetitions associated with the subsequent preamble transmission and the power associated with the subsequent preamble transmission until reaching a maximum number of repetitions and the maximum power;

increasing, after the failure of each previous preamble transmission and based on the second indication, the power associated with a set of subsequent preamble transmissions while maintaining a first number of repetitions associated with the set of subsequent preamble transmissions and, upon using the maximum power for a subsequent preamble transmission in the set of subsequent preamble transmissions, increasing the number of repetitions associated with one or more subsequent preamble transmissions at the maximum power until reaching the maximum number of repetitions;

increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions;

increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the set of subsequent preamble transmissions while maintaining a first power associated with the set of subsequent preamble transmissions and, upon using the maximum number of repetitions for the subsequent preamble transmission in the set of subsequent preamble transmissions and based on the second indication, increasing the power associated with one or more subsequent preamble transmissions at the maximum number of repetitions until reaching the maximum power;

increasing, after a failure of a first configured number of previous preamble transmissions, the number of repetitions associated with the set of subsequent preamble transmissions until reaching the maximum number of repetitions and increasing, after a failure of a second configured number of previous preamble transmissions and based on the second indication, the power associated with the subsequent preamble transmission until reaching the maximum power; or

iteratively, (1) beginning from the first number of repetitions associated with the preamble transmission at a current power, increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions, and, after the failure of a preamble transmission associated with the maximum number of repetitions, (2) increasing the current power based on the second indication until the maximum power is reached.
A method of wireless communication for a network device, comprising:

outputting a first indication of a plurality of resources for a preamble transmission from at least one active backscatter device and a corresponding plurality of downlink signal strength ranges;

outputting a second indication for a set of power ramp steps associated with the plurality of resources; and

receiving at least one random access message associated with the at least one active backscatter device based on the first indication and the second indication.
The method of claim 28, wherein, for at least a first downlink signal strength range, corresponding resources comprise multiple sets of resources, wherein each set of resources is associated with a range of amplification capabilities of backscatter devices.
The method of claim 28, further comprising:

outputting a third indication for a repetition pattern associated with the preamble transmission, wherein each preamble transmission is associated with one or more repetitions and the repetition pattern comprises one of:

increasing, after a failure of each previous preamble transmission and based on the second indication, a power associated with a subsequent preamble transmission until reaching a maximum power;

increasing, after the failure of each previous preamble transmission and based on the second indication, a number of repetitions associated with the subsequent preamble transmission and the power associated with the subsequent preamble transmission until reaching a maximum number of repetitions and the maximum power;

increasing, after the failure of each previous preamble transmission and based on the second indication, the power associated with a set of subsequent preamble transmissions while maintaining a first number of repetitions associated with the set of subsequent preamble transmissions and, upon using the maximum power for a subsequent preamble transmission in the set of subsequent preamble transmissions, increasing the number of repetitions associated with one or more subsequent preamble transmissions at the maximum power until reaching the maximum number of repetitions;

increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions;

increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the set of subsequent preamble transmissions while maintaining a first power associated with the set of subsequent preamble transmissions and, upon using the maximum number of repetitions for the subsequent preamble transmission in the set of subsequent preamble transmissions and based on the second indication, increasing the power associated with one or more subsequent preamble transmissions at the maximum number of repetitions until reaching the maximum power;

increasing, after a failure of a first configured number of previous preamble transmissions, the number of repetitions associated with the set of subsequent preamble transmissions until reaching the maximum number of repetitions and increasing, after a failure of a second configured number of previous preamble transmissions and based on the second indication, the power associated with the subsequent preamble transmission until reaching the maximum power; or

iteratively, (1) beginning from the first number of repetitions associated with the preamble transmission at a current power, increasing, after the failure of each previous preamble transmission, the number of repetitions associated with the subsequent preamble transmission until reaching the maximum number of repetitions, and, after the failure of a preamble transmission associated with the maximum number of repetitions, (2) increasing the current power based on the second indication until the maximum power is reached.