WO2025156361A1

WO2025156361A1 - Method, device, and system for access procedure in wireless networks

Info

Publication number: WO2025156361A1
Application number: PCT/CN2024/079507
Authority: WO
Inventors: Li NIU; Ting LU; Yuan Gao
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2024-03-01
Filing date: 2024-03-01
Publication date: 2025-07-31
Anticipated expiration: 2026-09-01

Abstract

This disclosure relates generally to a method, device, and system for resource management in a wireless network. One method performed by a wireless device may include transmitting, to a network node, a Msg3 of an access procedure, the Msg3 being a start of the access procedure. The Msg3 is characterized by at least one of following: the Msg3 is addressed by a RNTI; the Msg3 carries the RNTI; or a MAC CE of the Msg3 carries the RNTI. At least a portion of a physical uplink channel carrying the Msg3 is scrambled by an RNTI.

Description

METHOD, DEVICE, AND SYSTEM FOR ACCESS PROCEDURE IN WIRELESS NETWORKS

TECHNICAL FIELD

This disclosure is directed generally to wireless communications, and particularly to a method, device, and system for an access procedure in a wireless network, such as a 3G, 4G, 5G, or 6G wireless network.

BACKGROUND

To satisfy the demands of the unprecedented growth of mobile subscribers and large number of novel services, the wireless communication networks require continuous expansion, which leads to the continuous contention for various resources. Efficient access procedure is critical for reducing access latency and resource utilization in a wireless communication network.

SUMMARY

This disclosure is directed to a method, device, and system for an access procedure for establishing UE access to a wireless network, such as 3G, 4G, 5G, or 6G wireless network.

In some embodiments, a method performed by a wireless device is disclosed. The method may include: performed by a wireless device may include transmitting, to a network node, a Msg3 of an access procedure, the Msg3 being a start of the access procedure. The access procedure is a two step procedure starting with the Msg3. The Msg3 is characterized by at least one of following: the Msg3 is addressed by a RNTI; the Msg3 carries the RNTI; or a MAC CE of the Msg3 carries the RNTI. At least a portion of a physical uplink channel carrying the Msg3 is scrambled by an RNTI. The access procedure only includes two steps: UE sending a Msg3 to a base station, and UE receiving a Msg4 from the base station. After a successful access procedure, a connection between the UE and the base station is established.

In some embodiments, a method performed by a network element/network node/Wireless Reception/Transmission Unit (WRTU) is disclosed. The method may include: receiving, from a wireless device, a Msg3 of an access procedure for establishing a connection with the network node, the Msg3 being a start of the access procedure. The Msg3 is characterized by at least one of following: the Msg3 is addressed by a RNTI; the Msg3 carries the RNTI; or a MAC CE of the Msg3 carries the RNTI. At least a portion of a physical uplink channel carrying the Msg3 is scrambled by an RNTI.

In some embodiments, there is a wireless device, a network element, a WRTU, or a network node comprising a processor and a memory, wherein the processor is configured to read code from the memory and implement any methods recited in any of the embodiments.

In some embodiments, a computer program product comprising a computer-readable program medium code stored thereupon, the code, when executed by a processor, causing the processor to implement any method recited in any of the embodiments.

The above embodiments and other aspects and alternatives of their implementations are described in greater detail in the drawings, the descriptions, and the claims below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example wireless communication network.

FIG. 2 shows an example wireless network node.

FIG. 3 shows an example user equipment.

FIG. 4 shows an example non-terrestrial network deployment of a wireless network.

FIG. 5A shows an example contention based 4-step random access procedure.

FIG. 5B shows an example contention based 2-step access procedure starting from Msg3.

FIG. 5C shows various candidate uplink resources for the 2-step access procedure.

FIG. 6 shows an example UL resource configuration list according to one embodiment in this disclosure.

FIG. 7 shows example candidate resources and pending UL data.

FIG. 8 shows an example UL resource configuration list with associated conditions according to one embodiment in this disclosure.

FIG. 9 shows an example UL resource configuration list configured with TA timers.

FIG. 10 shows an example UL resource selection for retransmitting Msg3.

DETAILED DESCRIPTION

Wireless Communication Network

FIG. 1 shows an exemplary wireless communication network 100 that includes a core network 110 and a radio access network (RAN) 120. The core network 110 further includes at least one Mobility Management Entity (MME) 112 and/or at least one Access and Mobility Management Function (AMF) . Other functions that may be included in the core network 110 are not shown in FIG. 1. The RAN 120 further includes multiple base stations, for example, base stations 122 and 124. The base stations may include at least one evolved NodeB (eNB) for 4G LTE, an enhanced LTE eNB (ng-eNB) , or a Next generation NodeB (gNB) for 5G New Radio (NR) , or any other type of signal transmitting/receiving device such as a UMTS NodeB. The eNB 122 communicates with the MME 112 via an S1 interface. Both the eNB 122 and gNB 124 may connect to the AMF 114 via an Ng interface. Each base station manages and supports at least one cell. For example, the base station gNB 124 may be configured to manage and support cell 1, cell 2, and cell 3.

The gNB 124 may include a central unit (CU) and at least one distributed unit (DU) . The CU and the DU may be co-located in a same location, or they may be split in different locations. The CU and the DU may be connected via an F1 interface. Alternatively, for an eNB which is capable of connecting to the 5G network, it may also be similarly divided into a CU and at least one DU, referred to as ng-eNB-CU and ng-eNB-DU, respectively. The ng-eNB-CU and the ng-eNB-DU may be connected via a W1 interface.

The wireless communication network 100 may include one or more tracking areas. A tracking area may include a set of cells managed by at least one base station. For example, tracking area 1 labeled as 140 includes cell 1, cell 2, and cell 3, and may further include more cells that may be managed by other base stations and not shown in FIG. 1. The wireless communication network 100 may also include at least one UE 160. The UE may select a cell among multiple cells supported by a base station to communication with the base station through Over the Air (OTA) radio communication interfaces and resources, and when the UE 160 travels in the wireless communication network 100, it may reselect a cell for communications. For example, the UE 160 may initially select cell 1 to communicate with base station 124, and it may then reselect cell 2 at certain later time point. The cell selection or reselection by the UE 160 may be based on wireless signal strength/quality in the various cells and other factors.

The wireless communication network 100 may be implemented as, for example, a 2G, 3G, 4G/LTE, or 5G cellular communication network. Correspondingly, the base stations 122 and 124 may be implemented as a 2G base station, a 3G NodeB, an LTE eNB, or a 5G NR gNB. The UE 160 may be implemented as mobile or fixed communication devices which are capable of accessing the wireless communication network 100. The UE 160 may include but is not limited to mobile phones, laptop computers, tablets, personal digital assistants, wearable devices, Internet of Things (IoT) devices, MTC/eMTC devices, distributed remote sensor devices, roadside assistant equipment, XR devices, and desktop computers. The UE 160 may also be generally referred to as a wireless communication device, or a wireless terminal. The UE 160 may support sidelink communication to another UE via a PC5 interface.

While the description below focuses on cellular wireless communication systems as shown in FIG. 1, the underlying principles are applicable to other types of wireless communication systems for paging wireless devices. These other wireless systems may include but are not limited to Wi-Fi, Bluetooth, ZigBee, and WiMax networks.

FIG. 2 shows an example of electronic device 200 to implement a network base station (e.g., a radio access network node) , a core network (CN) , and/or an operation and maintenance (OAM) . Optionally in one implementation, the example electronic device 200 may include radio transmitting/receiving (Tx/Rx) circuitry 208 to transmit/receive communication with UEs and/or other base stations. Optionally in one implementation, the electronic device 200 may also include network interface circuitry 209 to communicate the base station with other base stations and/or a core network, e.g., optical or wireline interconnects, Ethernet, and/or other data transmission mediums/protocols. The electronic device 200 may optionally include an input/output (I/O) interface 206 to communicate with an operator or the like.

The electronic device 200 may also include system circuitry 204. System circuitry 204 may include processor (s) 221 and/or memory 222. Memory 222 may include an operating system 224, instructions 226, and parameters 228. Instructions 226 may be configured for the one or more of the processors 221 to perform the functions of the network node. The parameters 228 may include parameters to support execution of the instructions 226. For example, parameters may include network protocol settings, bandwidth parameters, radio frequency mapping assignments, and/or other parameters.

FIG. 3 shows an example of an electronic device to implement a terminal device 300 (for example, a user equipment (UE) ) . The UE 300 may be a mobile device, for example, a smart phone or a mobile communication module disposed in a vehicle. The UE 300 may include a portion or all of the following: communication interfaces 302, a system circuitry 304, an input/output interfaces (I/O) 306, a display circuitry 308, and a storage 309. The display circuitry may include a user interface 310. The system circuitry 304 may include any combination of hardware, software, firmware, or other logic/circuitry. The system circuitry 304 may be implemented, for example, with one or more systems on a chip (SoC) , application specific integrated circuits (ASIC) , discrete analog and digital circuits, and other circuitry. The system circuitry 304 may be a part of the implementation of any desired functionality in the UE 300. In that regard, the system circuitry 304 may include logic that facilitates, as examples, decoding and playing music and video, e.g., MP3, MP4, MPEG, AVI, FLAC, AC3, or WAV decoding and playback; running applications; accepting user inputs; saving and retrieving application data; establishing, maintaining, and terminating cellular phone calls or data connections for, as one example, internet connectivity; establishing, maintaining, and terminating wireless network connections, Bluetooth connections, or other connections; and displaying relevant information on the user interface 310. The user interface 310 and the inputs/output (I/O) interfaces 306 may include a graphical user interface, touch sensitive display, haptic feedback or other haptic output, voice or facial recognition inputs, buttons, switches, speakers and other user interface elements. Additional examples of the I/O interfaces 306 may include microphones, video and still image cameras, temperature sensors, vibration sensors, rotation and orientation sensors, headset and microphone input /output jacks, Universal Serial Bus (USB) connectors, memory card slots, radiation sensors (e.g., IR sensors) , and other types of inputs.

Referring to FIG. 3, the communication interfaces 302 may include a Radio Frequency (RF) transmit (Tx) and receive (Rx) circuitry 316 which handles transmission and reception of signals through one or more antennas 314. The communication interface 302 may include one or more transceivers. The transceivers may be wireless transceivers that include modulation /demodulation circuitry, digital to analog converters (DACs) , shaping tables, analog to digital converters (ADCs) , filters, waveform shapers, filters, pre-amplifiers, power amplifiers and/or other logic for transmitting and receiving through one or more antennas, or (for some devices) through a physical (e.g., wireline) medium. The transmitted and received signals may adhere to any of a diverse array of formats, protocols, modulations (e.g., QPSK, 16-QAM, 64-QAM, or 256-QAM) , frequency channels, bit rates, and encodings. As one specific example, the communication interfaces 302 may include transceivers that support transmission and reception under the 2G, 3G, BT, WiFi, Universal Mobile Telecommunications System (UMTS) , High Speed Packet Access (HSPA) +, 4G /Long Term Evolution (LTE) , 5G (also referred to as New Radio, or 5G NR) , and 6G standards. The techniques described below, however, are applicable to other wireless communications technologies whether arising from the 3rd Generation Partnership Project (3GPP) , GSM Association, 3GPP2, IEEE, or other partnerships or standards bodies.

Referring to FIG. 3, the system circuitry 304 may include one or more processors 321 and memories 322. The memory 322 stores, for example, an operating system 324, instructions 326, and parameters 328. The processor 321 is configured to execute the instructions 326 to carry out desired functionality for the UE 300. The parameters 328 may provide and specify configuration and operating options for the instructions 326. The memory 322 may also store any BT, WiFi, 3G, 4G, 5G, 6G or other data that the UE 300 will send, or has received, through the communication interfaces 302. In various implementations, a system power for the UE 300 may be supplied by a power storage device, such as a battery or a transformer.

Non-terrestrial Network

In certain areas such as mountains, deserts, oceans, etc., wireless communication network deployments may be expensive and difficult. However, with the advancement of science and technology, there is a great demand of data collections and communications in these remote regions. For example, there may be a need to collect meteorological data at a mountain peak or desert.

In non-terrestrial network (NTN) deployments, a satellite may provide signal coverage to a large area even in the remote regions. The non-terrestrial network may be deployed in addition to a terrestrial network, thereby further extending coverage of, for example a terrestrial cellular network. The NTN may be deployed to enhance network resilience in scenarios such as disaster recovery or emergency communications. Additionally, NTN may play an important role in IoT deployments, and mission-critical services, and therefore extend the business of network operators.

In an NTN, a satellite may be associated with a base station, or be part of (or as an extension of) the base station. FIG. 4 shows an example non-terrestrial network (NTN) 400 that provides wireless network access to a UE. In the non-terrestrial network 400, a satellite 402 provides communication links between the ground areas. Similar to a traditional cellular network, the covered ground areas may be divided into cells, or more specifically, satellite cells, such as cells 1 to 4 as shown in FIG. 4. These cells may provide signal coverage for the UE. A radio link between satellite and UE may be referred to as a service link. The satellite 402 may generate several beams over a given service area bounded by its field of view. The footprints of the beams may be of elliptic shapes.

The satellite 402 may be placed into Low-Earth Orbit (LEO) , or Geostationary Earth Orbit (GEO) . The geostationary Earth orbit may be a circular orbit at 35, 786 km (kilometer) above the earth's equator and following the direction of the Earth's rotation. A GEO satellite in such an orbit may have an orbital period equal to the Earth's rotational period and thus appears motionless, at a fixed position in the sky, to ground observers. The typical beam footprint size of the GEO is about 200-3500 km. The low Earth Orbit may be an orbit around the earth with an altitude between 300 km to 1500 km. A LEO satellite in such an orbit encircle around the earth with the speed of, for example, 7.56 km per second. The beam footprint size of LEO may be 50 km to 1000 km.

The NTN 400 may include an NTN gateway 404 which may be an earth station located at the surface of earth, and providing sufficient RF power and RF sensitivity for accessing the satellite 402. The NTN Gateway 404 may be a transport network layer (TNL) node and may provide access to, for example, a core network, a radio access network, or a data network. The wireless link between the NTN Gateway 404 and satellite 402 may be referred to as a feeder link.

Currently, IoT connectivity often necessitates extensive coverage, particularly in remote or underserved areas where traditional terrestrial networks may not be sufficient. NTN deployment may address this need by providing wide-area coverage and extending connectivity to areas where terrestrial infrastructure is impractical or unavailable. Narrowband IoT (NB-IoT) or enhanced Machine Type Communication (eMTC) are low-power, wide-area (LPWA) cellular technologies designed specifically for IoT applications, offering long-range connectivity, efficient power usage, and support for a large number of devices. Using NTN to support NB-IoT and eMTC is emerging as a significant trend in wireless communication development.

NTN for NB-IoT deployments are already underway, marking a significant step in expanding IoT connectivity to remote or underserved areas. In the early stage deployments, IoT-NTN, particularly NB-IoT, will need to support massive capacity in terms of the number and types of UEs, which may have varying characteristics (e.g., low-cost devices, wearables, etc. ) . For cost saving purpose, many of the IoT UEs are low cost, lower end, or low performance UEs. Therefore, special consideration is needed to cover a wide range of UEs.

In this disclosure, various embodiments are disclosed, aiming to address the challenge of supporting diverse UE types and maximizing UL capacity. For example, methods tailored to the NTN/IoT environment for configuring and allocating uplink resource are described. These methods provide mechanisms for efficient resource configuration and allocation and enhances the overall capacity of the uplink channel. In particular, these methods may apply to the Random Access Procedure (RAP) , to configure the UL resource required therein. For another example, some embodiments are described, to unlock additional UL capacity potential by de-coupling the uplink (UL) from the downlink (DL) as much as possible.

Random Access

In a mobile communication system (e.g., a 5G system, a 4G LTE system, a 3G UMTS system, etc. ) , the UE and the network need to establish a connection for the transmission of, for example, service data or application data. In general, an access procedure is needed in order for the UE to access the network.

In this disclosure, the network may include a Radio Access Network (RAN) which may further include one or more base stations. The network may further include a core network. A connection between the UE and the network may include, for example, a connection between the UE and a base station in the network, a connection between the UE and a cell in the network, etc.

In order to establish uplink synchronization and/or Radio Resource Control (RRC) connection, UE may need to perform a random access procedure, also known as RACH (Random Access Channel) procedure, or a PRACH (Physica RACH) procedure. There may exist different implementations for the RACH procedure, for example, 4-step Contention Based Random Access (CBRA) procedure, and 2-step CBRA procedure. There may also exist RACH procedures that are contention free.

FIG. 5A shows an example 4-step CBRA procedure which includes follow steps: Step 1:

UE selects a preamble (or preamble resource) from available PRACH resource pool, and sends the selected preamble (e.g., in Msg1) to the network (e.g., a base station such as a gNB) . Note that at same time, other UE (s) may also select the same preamble resource for a RACH procedure, which may lead to a contention.

Step 2:

After reception of preamble, the base station sends back a random access response (RAR) (e.g., in Msg2) to the UE. The RAR may include a temporary Cell Radio Network Temporary Identifier (C-RNTI) allocated by the base station, and/or an Uplink (UL) grant.

Step 3:

UE stores the temporary C-RNTI and sends to the base station a third message (e.g., Msg3) using the UL grant indicated in the RAR. Exemplarily, the Msg3 may be sent from RRC layer, in which case the Msg3 may also be referred to as an RRC Msg3. The Msg3 may carry an identity, such as a UE Contention Resolution Identity, for the purpose of contention resolution.

After sending Msg3, the UE may start a contention resolution timer (e.g., ra-ContentionResolutionTimer) , and monitor the PDCCH.

Step 4:

The base station may send the PDCCH addressed to the temporary C-RNTI (as described in steps 2 and 3, may be noted as TEMPORARY_C-RNTI) for Msg4 scheduling. The base station may assist the UE in contention resolution by using a C-RNTI on the PDCCH or using the UE Contention Resolution Identity (which the base station obtains based on the UL CCCH SDU (e.g., Msg3) received in previous step) on the PDSCH. The base station may send a Msg4 for contention resolution.

UE obtains the PDCCH addressed to its temporary C-RNTI. If the MAC PDU associated with the Msg4 contains a UE Contention Resolution Identity MAC CE, and the UE Contention Resolution Identity in the MAC CE matches the UL CCCH SDU (e.g., Msg3) , the UE considers the Contention Resolution to be successful; otherwise if the UE Contention Resolution Identity does not match, the UE considers the Contention Resolution to be not successful, discards the TEMPORARY_C-RNTI and triggers the RACH procedure again.

If the ra-ContentionResolutionTimer expires before the UE is able to determine that the Contention Resolution is successful, the UE considers the Contention Resolution not successful, discards the TEMPORARY_C-RNTI and triggers the PRACH procedure again.

Two Step Access Procedure

The RACH procedure described above involves 4 steps, which is a big overhead for the UE and the network. In this disclosure, to reduce the overhead and expedite the access procedure to the UE to access the network, a simplified two step access procedure is introduced, which is illustrated in FIG. 5B. As shown in FIG. 5B, UE may start directly from sending a Msg3 to the network, as an indication for network access request or network connection request. UE may then receive a Msg4 to serve, for example, contention resolution and indication of successful access establishment.

In this disclosure, an Uplink (UL) resource pool is introduced. UE may be configured with a UL resource pool via, one or more UL resource configurations, with each configuration corresponding to an UL resource. When sending the Msg3, UE may select an UL resource from the UL resource pool for the uplink transmission.

The UL resource may be shared with other UEs. Using shared UL resource, the Msg3 transmission is contention based, as multiple UE may use the same UL resource for Msg3 transmission simultaneously. Similar to the Msg3 in the above 4 step random access procedure, Msg3 in this two step access procedure may also carry an RNTI. The RNTI may be configured by the base station and sent to the UE via, for example, broadcast or RRC message. The RNTI may also be an RNTI stored by the UE when UE was in a prevous connected state. The RNTI may also be generate by the UE itself based on certain rules. Various embodiments in this disclosure will cover details on various types of RNTIs used in Msg3. In this disclosure, the access procedure may be referred to as a contention based access procedure (or contention based random access procedure) if the transmission of Msg3 is contention based.

Msg4 may be used similarly for contention resolution. In this disclosure, Msg4 may be addressed by an RNTI (so UE can tell if it’s the recipient of the MSg4) , and/or Msg4 may be used to carry an RNTI, and UE may store the RNTI for future use.

Alternatively, the UL resource pool may include one or more UL resources assigned to or dedicated to the UE, and UE may use these dedicated UL resources to transmit contention free Msg3.

Alternatively, in addition to or instead of the UL resource pool, UE may be configured with a dedicated Preconfigured Uplink Resource (PUR) , which the UE may use transmit contention free Msg3.

FIG. 5C shows the various UL resources from which a UE may select an UL resource.

In this disclosure, the two step access procedure may be considered as an improved, or simplified random access procedure. All embodiments in this disclosure apply to the two step access procedure, as well as the 4 step procedure.

Embodiment 1: UL Resource Configuration

In this embodiment, a UL resource pool is configured to be used for, for example, contention-based Msg3, or other types of contention-based or contention free uplink transmissions. The UL resource pool may include multiple UL resources. Once configured, a UE may use one or more resources selected from the UL resource pool for UL transmissions, such as a Msg3 transmission.

FIG. 6 shows an example UL resource configuration list 600, which may be used to configure the UL resource pool. As shown in FIG. 6, the UL resource configuration list 600 may include n UL resource configurations (with indexes from 1 to n) . Each UL resource configuration may be assigned with an index for identification purpose, and may include corresponding UL resource configuration parameters (see details on these parameters below) . Each UL resource configuration may be used to configure a corresponding UL resource. Generally speaking, each UL resource may have its time domain resource allocation and frequency domain resource allocation. Additionally, a UL resource may further be configured with a code domain allocation (e.g., an assigned code sequence, modulation scheme, etc. ) . Note that as a special case, the UL resource configuration list may only have one entry (i.e., there is only one UL resource configuration in the list) , and in this case, the UL resource configuration index may not be needed. The number of entries in the list may also be referred to as a size of the list.

There are multiples ways to configure the UL resource configuration list. For example, the UL resource configuration list may be configured in a broadcast manner via, for example, a broadcast message, a System Information Block (SIB) message, etc. When the broadcast manner is used, multiple UEs may be configured with the UL resource configuration list simultaneously. The UL resource configuration list may also be configured via a unicast manner via, for example, a Radio Resource Control (RRC) message. The configuration of the UL resource configuration list may be sent in one message or split into multiple messages.

The following description uses base station for exemplary purpose. In the examples below, the base station may transmit the UL resource configuration list to UE (s) . The same underlying concept also applies to other entities that may communicate with the UE, such as a cell, in which case, the cell may transmit the UL resource configuration list to UE (s) .

Each UL resource configuration in the UL resource configuration list may be used to configure a corresponding UL resource and may include at least one of following parameters:

● An index identifying each UL resource configuration in the list of UL resource configurations;

● A starting time of the corresponding UL resource;

● A length of the corresponding UL resource in time domain;

● A Resource Block (RB) number of the corresponding UL resource;

● A Resource Unit (RU) number of the corresponding UL resource;

● A subcarrier number of the corresponding UL resource;

● A periodicity of the corresponding UL resource;

● A Transport Block Size (TBS) of the corresponding UL resource;

● An anchor carrier or a non-anchor carrier of the corresponding UL resource;

● A Physical Downlink Control Channel (PDCCH) search space configuration of the corresponding UL resource;

● A repetition number of the corresponding UL resource;

● A SubCarrier configuration of the corresponding UL resource; or

● A Modulation and Coding Scheme of the corresponding UL resource.

In some example implementations, the base station may broadcast the UL resource configuration list via SIB.

In some example implementations, the base station may broadcast a common UL resource configuration list that may be shared by UEs. Each UL resource configuration in the list may include one or more configuration parameters for the corresponding UL resource, such as: a starting time, an RB number, a periodicity, a Transport Block Size (TBS) , an anchor carrier or a non-anchor carrier, etc.

In some example implementations, the base station may send the UL resource configuration list via an RRC message. Each UL resource configuration in the list may include one or more configuration parameters for the corresponding UL resource, such as: a starting time, an RB number, a periodicity, a TBS, an anchor carrier or a non-anchor carrier, etc. Specifically, as the RRC message is sent to a specific UE, the UL resource configuration list may be customized by the base station for the UE based on, for example, assistance information sent by the UE. The UE may send assistance information to the base station via an RRC message, such as a PURConfigurationRequest message. The assistance information may include information about the requested UL resource such as: periodicity, time offset, Transport Block Size (TBS) , RRC Acknowledge (RRC Ack) , etc. The assistance information may further include UE characteristics data. Base on UE assistance information, the base station may customize a corresponding UL resource configuration list for the UE, and send the customized UL resource configuration list via an RRC message, such as an RRC release message.

Note that from the base station side, the base station may send a same UL resource configuration list to multiple UEs.

In some example implementations, the base station may send a UL resource configuration indicator to the UE via, for example, an RRC message, so the UE may select the UL resource configuration from the UL resource configuration list based on the indicator. The UL resource configuration indicator may be the index for the UL resource configuration, as shown in FIG. 6. As the UE is configured with a UL resource configuration list that may include multiple UL resource configurations, the base station may determine the index based on the UE assistance information as described above, such that the selected UL resource configuration is adapted to the UE assistance information provided by the UE.

Note that the base station may indicate a same UL resource configuration to multiple UEs.

In some example implementations, an UL resource configuration enablement mechanism may be implemented. This mechanism may be considered as an access control, such that UE can only use the UL resource configuration list when it’s enabled. For example, after the UL resource configuration list is configured, the list may be in an inactive or disabled mode, and UE is not able to use it. The base station may manipulate the mode of the UL resource configuration list by sending an enablement indicator to the UE via, for example, an RRC message.

Specifically, the base station may be able to determine or predict that UE needs UL resource for contention-based Msg3 transmission. The base station may send an enablement indication to enable or disable UE to use the UL resource configuration list via, for example, an RRC release message.

In one example, the UL resource configuration list may include only one UL resource configuration. In this case, the enablement indication also serves as a selection indication, such that once the list is enabled, there is no need to further indicate a UL resource configuration separately.

Under the enablement mechanism, UE may not transmit Msg3 when the UL resource configuration list is in disabled mode.

In some example implementations, the UL resource configuration list may be further divided into one or more groups (or sub-lists) . In this case, each UL resource configuration may be assigned a group ID. Exemplarily, the base station may first configure the UL resource configuration list (which includes multiple groups) via a broadcast message, and then send an RRC message to the UE carrying a group ID. That is, UE is assigned a group ID, and may only select UL resource configuration with the same group ID.

In some implementations, further limitation to the UL resource configuration list may be added. For example, one or more UL resource configurations in the UL resource configuration list may be configured with a validity area, and a specific UL resource configuration is only valid when the UE is inside the corresponding validity area. Optionally, when the UE moves out of the validity area, UE may choose release the corresponding UL resource configuration. The validity area may include at least one of: a list of cell identities, a list of satellite identities, a list of track area identities, and the like.

In some implementations, further limitation to the UL resource configuration list may be added. For example, one or more UL resource configurations in the UL resource configuration list may be configured with a validity time, or validity time period (s) . A UL resource configuration is only valid, or can only be applied to UL resource that falls within this time period. If the current time is outside the validity time period, or if the UL resource configured by the UL resource configuration is outside the validity time period, then the UL resource configuration cannot be used. Optionally, UE may choose to release the UL resource configuration if current time passed the validity period. The validity time may be in the form of one or more time durations, one or more transmission occasions, and the like. The validity time could start to count after the UL resource configuration list takes effect or is configured, or after the first valid transmission occasion. Details for the first valid transmission occasion is described in below sections.

Embodiment 2: UL Resource Start Time

In this embodiment, the UE already has a UL resource configuration list configured using embodiment described above. Optionally, the UL resource configuration list may only have one entry.

In some example implementations, the UL resource configuration list may be configured by an RRC message. From a time domain perspective, the first (i.e., nearest) UL resource occasion configured by the UL resource configuration list is located by: a Hyper System Frame Number (HSFN) , a System Frame Number (SFN) (this is the SF inside the HSF identified by the HSFN) , and a subframe (inside the SF identified by the SFN) .

The frame number of the HSF, HSFN, may be determined as:

HSFN = (HSFN_Ref + offset) mod 1024 (i.e., occurring after (FLOOR (offset/1024) H-SFN cycles) , wherein mod is the modulo operation.

● HSFN_Ref corresponds to the hyper system frame number of an HSF in which the first or last subframe of the first transmission, or the first or last subframe of the last transmission of the RRC message (used for configuring the UL resource configuration list) . Note that the RRC message may need multiple transmissions.

● offset is an offset from the start of an HSF level period. Each HSF level period may include n HSF, n being an integer. Offset may be counted as in the unit of HSFs. For example, each HSF level period has 10 HSF, and an offset equal to 2 means the offset is 2 HSFs from the start of the HSF level period. Offset may be preconfigured.

● The HSF level periodicity may be preconfigured, in the unit of number of HSFs.

The System Frame Number, and/or the subframe for the first UL resource occasion may be preconfigured.

In some example implementations, the UL resource configuration list may be configured by a broadcast message, such as an SIB message. From a time domain perspective, the first UL resource occasion configured by the UL resource configuration list is located by: a Hyper System Frame Number (HSFN) , a System Frame Number (SFN) (this is the SF inside the HSF identified by the HSFN) , and a subframe (inside the SF identified by the SFN) .

The frame number of the HSF, HSFN, may be determined as:

HSFN = (HSFN_Ref + offset) mod 1024 occurring after FLOOR (offset/1024) H-SFN cycles

● HSFN_Ref corresponds to the hyper system frame number of an HSF in which the first or last subframe of the System Information (SI) window of the SIB message (used for configuring the UL resource configuration list) .

● offset is an offset from the start of an HSF level period. Each HSF level period may include n HSF, n being an integer. Offset may be counted as number of HSFs. For example, each HSF level period has 10 HSF, and an offset equal to 2 means the offset is 2 HSFs from the start of the HSF level period. Offset may be preconfigured.

Embodiment 3: Msg3 Contention-free Operation

In this embodiment, UE may perform Msg3 contention-free operation (i.e., transmitting a contention-free Msg3) .

The base station may indicate an Orthogonal Cover Code (OCC) index to the UE via, for example, an RRC message. The OCC index may be used to determine the code sequence that is used to encode/produce the Physical Uplink Shared Channel (PUSCH) of Msg3. Specifically, the base station may indicate different OCC indexes to different UEs, therefore the PUSCHs (for Msg3) of those UEs are orthogonal in UL resource.

In some example implementations, the OCC index may be included as part of UL resource configuration parameters. When the UL resource configuration list is configured, one or more UL resource configurations may have an OCC index parameter.

In some example implementations, the OCC index for a particular UL resource configuration may be separately indicated.

In this embodiment, via the usage of the OCC index, a code sequence may be determined to ensure that the PUSCHs for Msg3 are orthogonal, therefore the Msg3 may be transmitted contention free.

Embodiment 4: Resource Selection

With the introduction of the UL resource pool via the UL resource configuration list, each UL resource configuration in the list may correspond to a UL resource configured by it. These UL resources may have different time domain locations, and/or different frequency domain locations. Further, from a code domain perspective, these UL resources may have be associated with different code sequences.

FIG. 7 shows example UL resources that are configured by the UL resource configuration list. As shown in FIG. 7, there are 4 candidate UL resources 702, 704, 706, and 708. Each resource corresponds to a UL resource configuration in the UL resource configuration list, and may be considered as a transmission occasion. The block size of these UL resources represents the resource size (e.g., in byte, Megabyte, etc. ) .

In some example implementations, for a UL transmission, UE may select the nearest transmission occasion configured by a UL resource configuration. For example, when Msg3 is triggered (or in other words, when Msg3 is pending) , UE may select the nearest occasion to transmit Msg3. As shown in FIG. 7, at time t0, UE needs to transmit UL data (e.g., Msg3) . The nearest transmission occasion has the least waiting time. In this case, UL resource 702 is closest to t0 thus it has the least waiting time. UE may select 702 for UL transmission.

In some example implementations, a resource block size matching scheme may be used. Among all candidate UL resource blocks, UE may select the one that has a closest match to the size of pending UL data/message. That is, the size (capacity) of the selected UL resource has a closest matching that is larger than or equal to the size of the UL data/message (such as Msg3) . The size may be represented by, for example, Transport Block Size (TBS) , number of Resource Blocks (RBs) , number of Resource Units (RUs) , or number of subcarriers. As shown in FIG. 7, at time t0, UE needs to transmit UL data (e.g., Msg3) . There are 4 candidate UL resources (702, 704, 706, and 708) , each of which is configured by a UL resource configuration in the UL resource configuration list. In this case, UL resource 708 has the closest match in terms of block size. UE will select UL resource 708 for transmitting the pending UL data 710, which may include a Msg3.

In some example implementations, from a frequency domain perspective, UE may select the frequent occasion of UL resource randomly. When Msg3 is triggered, UE may select the frequent occasion to transmit Msg3 randomly.

Embodiment 5: Conditions for Using UL Resource

In this embodiment, after the UE is configured with a UL resource pool via the UL resource configuration list, certain condition (s) must be satisfied for the UE to use the UL resources configured by the list to transmit UL data/message, and in particular, for the UE to initiate a contention based Msg3.

In this embodiment, multiple thresholds are used. Unless otherwise specified, these thresholds may be pre-defined, or configured by the base station via, for example, RRC message, or broadcast message (e.g., SIB) .

In some example implementations, the Reference Signal Received Power (RSRP) of the UE must be higher than a RSRP threshold. In this condition, the channel quality is good enough to use the UL resource.

In some example implementations, the RSRP variation must be less than a threshold. The RSRP variation may include the variation between current RSRP and the last RSRP. The last RSRP may be measured when UE receives the UL resource configuration list, or when the UL resource configuration list takes effect. Alternatively, the RSRP variation may be measured for a particular duration. For example, the RSRP variation may be based on the measurement at starting time of the duration and at ending time of the duration. In this way, the configured TBS and/or MCS in a UL resource configuration may be applicable (i.e., the configured TBS and/or MCS can be applied only when this condition is met) . The RSRP variation threshold or the particular duration may be pre-defined, or configured by the base station via, for example, RRC message, or broadcast message (e.g., SIB) . When a UL resource configuration list takes effect, it means any one UL resource configuration in the list takes effect. Or, if there is only one UL resource configuration in the list, it means that the only one UL resource configuration takes effect.

In this disclosure, there are several types of variation measurement. For example, there are RSRP variation, Timing Advance (TA) variation, distance variation, and propagation delay variation. The measurement of these variations may follow the same principle as described above for RSRP variation. Using TA variation measurement as an example, the variation may be between a current TA and the last TA, and the last TA may be measured when UE receives the UL resource configuration list, or when the UL resource configuration list takes effect. That is, the last TA measurement is taken at a same time moment for measuring the last RSRP. Similarly, these variations may be measured for a particular duration, and the time duration is described above for RSRP variation. Similarly, a corresponding variation threshold (e.g., TA variation threshold, distance variation threshold, propagation delay variation) , as well as the measurement duration, may be pre-defined, or configured by the base station via, for example, RRC message, or broadcast message (e.g., SIB) .

In some example implementations, the data volume of UE’s UL data (e.g., payload size) that needs to be transmitted is less than or equals to a data volume threshold, or the TBS of a selected UL resource configuration. In this way, the large data is restricted/prohibited from utilizing the UL resource configured by the UL resource configuration list, prioritizing UL transmission with small data sizes.

In some example implementations, the UE’s UL synchronization must be maintained (UE must be UL synchronized) . UE must keep the UL synchronization with the base station. For example, the UL synchronization timer about must be running, or UE is able to obtain the UL synchronization before UE is able to transmit in the UL resource configured by a UL resource configuration in the UL resource configuration list.

In some example implementations, the TA (Timing Advance) of UE must be less than a TA threshold. UE may estimate the TA in service link, or in the combination of service link and feeder link. In this way, the channel quality is sufficient to utilize the UL resource.

In some example implementations, the TA variation must be less than a TA variation threshold. In this way, the configured TBS or MCS in a UL resource configuration may be applicable.

In some example implementations, the distance between UE and the reference point must be less than a distance threshold. UE could estimate the distance between UE and a reference point. Exemplarily, the reference point may be indicated by the base station and may include, for example, at least one of: the center of a cell associated with the base station, a satellite, or the base station. In this way, the UE is within the maximum allowed distance from the other end of a communication link and the channel quality may be sufficient to use the UL resource.

In some example implementations, the distance variation must be less than a distance variation threshold. In this way, the configured TBS or MCS in a UL resource configuration may be applicable.

In some example implementations, the propagation delay must be less than a threshold. UE could estimate the propagation delay between UE and satellite, or propagation delay in service link, or propagation delay as a sum of service link delay and feeder link delay (service link delay + feeder link delay) . In this way, the channel quality may be sufficient to use the UL resource.

In some example implementations, the propagation delay variation must be less than a propagation delay threshold. In this way, the configured TBS or MCS in a UL resource configuration may be applicable.

In some example implementations, a UL resource configuration in the UL resource configuration list can only be applied within a time range (i.e., the UL resource configuration has a validity period) . For example, at time point x, the UL resource configuration takes effect or is received by the UE. Starting from time point x, the UL resource configuration is valid for a validity duration. Or at time point z, the UL resource configuration losses effect. Then during time x～z, the UL resource configuration is valid. Rather than using the time when the UL resource configuration takes effect or is received by the UE, the time point x may also be pre-defined, or configured by the base station via, for example, RRC message, or broadcast message (e.g., SIB) . The duration may be pre-defined, or configured by the base station via, for example, RRC message, or broadcast message (e.g., SIB) .

Embodiment 6: Coverage Condition Correspondence

In this embodiment, one or more UL resource configurations in UL resource configuration list may be used for under one or more coverage levels or coverage conditions. UE could select the UL resource based on its coverage level and/or coverage condition and/or its location. For example, for UE1, if it is in cell coverage level 1, it may select a corresponding UL resource configuration 1 (which applies to or corresponds to coverage level 1) ; for UE2, if it is in cell coverage level 2, it may select a corresponding UL resource configuration 2 (which applies to or corresponds to coverage level 2) .

FIG. 8 shows an example UL resource configuration list. UL resource configuration 1 is associated with, or corresponds to at least one of following coverage condition thresholds: an RSRP threshold; a coverage level; a TA threshold; a propagation delay threshold; or a distance threshold. Based on one or more of the thresholds, the UE may be able to lookup a UL resource configuration from the UL resource configuration list that fit the threshold requirement. Other UL resource configurations in the list may also correspond to a set of threshold parameters.

In some example implementations, for a UL resource configuration, such as UL resource configuration 1 in FIG. 8, its corresponding coverage condition threshold (s) may be sent to the UE via a broadcast message, or an RRC message, after the UL resource configuration is sent to the UE.

In some example implementations, a UL resource configuration may be configured together with its corresponding coverage condition threshold (s) via, for example, a broadcast message, or an RRC message.

In some example implementations, one or more UL resource configurations correspond to a respective RSRP threshold (e.g., UL resource configuration n-1 in the UL resource configuration list) . If UE’s RSRP is higher than or equals to this RSRP threshold, the corresponding UL resource configuration could be selected.

In some example implementations, one or more UL resource configurations may correspond to a respective coverage level. UE may determine the coverage level based on RSRP. If UE is in a coverage level, a UL resource configuration corresponding to the coverage level may be selected.

In some example implementations, one or more UL resource configurations may correspond to a coverage level and an RSRP offset. UE may determine the coverage level based on a RSRP threshold. If UE is in a coverage level, and UE’s RSRP is higher than or equals to the sum of the RSRP threshold corresponding to the coverage level and the RSRP offset, the corresponding UL resource configuration (i.e., the UL resource configuration corresponds to the coverage level and the RSRP offset) may be selected.

In some example implementations, one or more UL resource configurations r may correspond to a TA threshold. UE may estimate TA in service link, or in a combination of service link and feeder link. If UE’s TA is less than or equals to the TA threshold, the corresponding UL resource configuration may be selected. Otherwise if UE’s TA is higher than the TA threshold, the corresponding UL resource configuration cannot be selected.

In some example implementations, one or more UL resource configurations r may correspond to a propagation delay threshold. UE could estimate propagation delay between UE and satellite, or in server link, or in a combination of service link and feeder link. If UE’s propagation delay is less than or equals to the propagation delay threshold, the corresponding UL resource configuration may be selected. Otherwise if UE’s propagation delay is higher than the propagation delay threshold, the corresponding UL resource configuration cannot be selected.

In some example implementations, one or more UL resource configurations r may correspond to a distance threshold. UE could estimate the distance between UE a reference point. The reference point may be indicated by, for example, the base station. The reference point may include at least one of: the center of a cell associated with the base station, a satellite, or the base station. If UE’s distance is less than or equals to the distance threshold, the corresponding UL resource configuration may be selected. Otherwise if UE’s distance is high than the distance threshold, the corresponding UL resource configuration cannot be selected.

Embodiment 7: UL Resource Pool Coexistence with Preconfigured Uplink Resource (PUR)

In some embodiments, in addition to the UL resource pool configured by the UL resource configuration list as described above, the UE may be separately configured with pre-configured UL Resource (PUR) . Therefore, there may be co-existence of the UL resource pool and PUR.

In some example implementations, for contention-based Msg3, if the base station configures the UL resource configuration list via, for example, a broadcast message, and the base station also configures the PUR for the UE, the UE may use the PUR to transmit the contention-based Msg3.

In some example implementations, for contention-based Msg3, if the base station configures the UL resource configuration list via, for example, a broadcast message, and the base station also configures the PUR for the UE. However, if the PUR expires, loses validity, or becomes invalid, the UE may select a UL resource configured by a UL resource configuration in the UL resource configuration list.

In some example implementations, for contention-based Msg3, if the base station configures the UL resource configuration list via, for example, a broadcast message, and the base station also configures the PUR for the UE. The UE may select a resource which has the least waiting time. For example, UE may have pending UL data (e.g., Msg3) to transmit, and UE will select from the PUR or UL resource pool, a nearest UL resource (i.e., with the least waiting time) . Therefore, a delay for Msg3 transmission is minimized.

In some example implementations, the UE is configured with both PUR and a UL resource pool (via UL resource configuration list) . In a particular time window (or time duration) , the UE may give higher selection priority to the PUR. That is, in the time window, if there is available transmission occasion in the PUR, then UE may select the UL resource from the PUR. For example, in a time window, UE may need to transmit a Msg3, or trigger a Mobile Origination (MO) procedure. If there is PUR resource available in the time window, then UE may select the UL resource for Msg3/MO from the PUR. Otherwise, if in the time window, there is no PUR resource available, but there is available UL resource configured by a UL resource configuration, then UE may select the UL resource configured by the UL resource configuration.

The time window may be configured by an RRC message or a broadcast message by the base station.

This embodiment may be used in combination with other embodiments. For example, for a UL resource configuration to be selected, the UL resource configuration has to meet certain preconditions, as specified in previous embodiments, including resource selection condition, conditions for using UL resources, coverage conditions, etc. For another example, UL resource configuration list, or UL resource configuration in the list has be enabled before it can be selected.

In this embodiment, Msg3 is used for exemplary purpose. Other types of UL data, such as contention based UL data may also apply.

Embodiment 8: UE Capability

As described in previous embodiments, UE may report assistance information to the base station, so the base station may customize UL resource configuration list for the UE. The assistance information may include UE capability information. In an NTN deployment, there may be various types of devices (e.g., IoT devices, Machine-Type Communication (MTC) devices, etc. ) . These devices may have special characteristics. For example, these devices may be designed with low cost hardware which has low performance in terms of transmission and/or reception capability. These devices may also have limited functions and may only support a limited set of operations.

In this embodiment, UE may report at least one of following capabilities:

● whether the UE supporting contention-based Msg3;

● whether the UE supporting contention-based Msg3 for control plane Cellular Internet of Things Evolved Packet System and the 5G System (CIoT EPS/5GS) optimization;

● whether the UE supporting contention-based Msg3 for user plane CIoT EPS/5GS optimization;

● whether the UE supporting Layer 1 (L1) acknowledgement in response to contention-based Msg3; or

● whether the UE supporting initiating contention-based Msg3 based on at least one of following conditions:

○ a Reference Signal Received Power (RSRP) of the wireless device is higher than a threshold;

○ an RSRP variation of the UE is lower than a threshold;

○ a size of a pending UL transmission is less than or equal to a threshold;

○ the size of the pending UL transmission is less than or equal to the TBS of the UL resource configuration in the list of UL resource configurations;

○ the wireless device is UL synchronized;

○ a Timing Advance (TA) of the UE is less than a threshold;

○ a TA variation of the UE is lower than a threshold;

○ a distance between the UE and a reference point is less than a threshold;

○ a distance variation between the UE and the reference point is less than a threshold;

○ a propagation delay is less than a threshold;

○ a propagation delay variation is less than a threshold; or

○ a current time is within a duration starting from the UL resource configuration list taking effect or being received.

Embodiment 8: Timing Advance

To maintain UL synchronization or keep UL synchronized, the UE may maintain a TA timer for one or more UL resource configurations in the UL resource configuration list.

FIG. 9 shows an example UL resource configuration list configured with TA timer (s) . As shown in FIG. 9, UL resource configurations 1 and n-1 are each associated with a respective TA timer. The TA timer may be configured jointly with the UL resource configuration list, or configured separately after the UL resource configuration list is configured.

In some example implementations, if Radio Resource Control (RRC) layer of UE receives the configuration about the TA timer for a UL resource configuration, MAC or RRC start this TA timer.

In some example implementations, if RRC layer of UE receives an order to release the TA time, the TA timer may be stopped by the Medium Access Control (MAC) layer or the RRC layer of the UE.

In some example implementations, if MAC layer receives a Timing Advance Command (TAC command) , or an updated TA for the TA timer, the MAC layer may apply a new timer value to the TA timer base on the TAC command or the updated TA, start the TA timer, and inform the RRC layer about the TA value updates.

In some example implementations, if a Random Access Channel (RACH) procedure (or Random Access procedure) is successfully completed, the MAC layer may start the TA timer, and inform the RRC layer about the TA value updates.

In some example implementations, if the TA timer is configured and not running, the corresponding UL resource (configured by a UL resource configuration in the UL resource configuration list) is invalid.

In some example implementations, if UE may be able to pre-compensate the TA before transmitting in a UL resource, the UL resource may be considered to be valid.

In some example implementations, if a TA timer is started, and then expires, the corresponding UL resource (configured by a UL resource configuration in the UL resource configuration list) becomes invalid.

Embodiment 9: Response Window for Msg4

In this embodiment, after transmitting the Msg3, in order to ensure the reception of Msg4, a response window is introduced.

After UE transmits a contention based Msg3, UE may start a timer for Msg4 response window. The Msg4 response window may also be referred to as a Msg4 reception window. UE will only attempt to receive Msg4 within this window. That is, when the timer is running, the response window is open and UE may receive Msg4 in the Msg4 response window. Once the timer expires, the response window is considered to be closed, and UE will not attempt to receive the Msg4 (corresponding to the previously sent Msg3) but will consider Msg4 reception to be failed.

In some example implementations, the Msg4 response window configuration may be configured by an RRC message or a broadcast message from the base station. the Msg4 response window configuration may include the length of the window, and number of PDCCH occasions in the window.

Embodiment 10: RNTI for Msg4

As described earlier, the Msg4 is a response for Msg3. Msg4 may include, for example, an RRC message, a Downlink Control Information (DCI) , a Medium Access Control –Control Element (MAC CE) , and so on.

In some example implementations, Msg4 may be transmitted in a physical downlink channel, such as a Physical Downlink Control Channel (PDCCH) , and/or a Physical Downlink Shared Channel (PDSCH) . The base station may use an RNTI to address the physical channel, for example, by using the RNTI to scramble the PDCCH/PDSCH, or Cyclic Redundancy Check (CRC) of the PDCCH/PDSCH. The scrambling action may also be considered as an “addressing” action, in which the RNTI may be considered as an address (or identifier) , as only recipient having the same RNTI may decode the channel correctly.

In this disclosure, Msg4 may generally include control data portion (e.g., DCI) and/or a payload data portion (e.g., data in PDSCH carrying contention resolution) that is scheduled by the control data portion.

In some example implementations, C-RNTI (Cell-RNTI) may be used for addressing Msg4. In connected mode, UE may be allocated a C-RNTI. UE may store it, and use it later for addressing Msg4.

In some example implementations, PUR-RNTI (Pre-configured Uplink Resource RNTI) may be used for addressing Msg4. UE may be allocated a PUR-RNTI via, for example, an RRC message from the base station. UE may store it, and use it later for addressing Msg4.

In some example implementations, a new UE specific RNTI, which is not currently implemented in wireless technology, is introduced in this disclosure. UE may be allocated this new RNTI via, for example, an RRC message, such as an RRC release message from the base station. UE may store it, and use it later for addressing Msg4.

In some example implementations, a common RNTI may be used for addressing Msg4. One or more, or all UEs may use this common RNTI for addressing Msg4.

In some example implementations, a group RNTI (or group common) may be used for addressing Msg4. UE may be allocated a group RNTI via, for example, an RRC message, such as RRC release message from the base station. Multiple UEs may share this same group RNTI. UE may store it, and use it later for addressing Msg4.

In some example implementations, UE may generate an RNTI based on time domain and/or frequency domain resource which UE used for transmitting Msg3. UE may be pre-configured with a UL resource pool by the base station via, for example, a broadcast message (e.g., System Information Block (SIB) message) , an RRC message, etc. The UL resource pool may be configured by a UL resource configuration list provisioned by the base station via these messages. When transmitting Msg3, UE may be indicated by the base station a particular UL resource configuration, or UE may determine the particular UL resource configuration base on, for example, pre-defined rules. UE may then use the UL resource configured by the particular UL resource configuration.

Based on the time and frequency resource of the selected UL resource for Msg3, UE may generate an RNTI that is specific or dedicated to the UE. Specifically, one or more of the following parameters related to time and frequency resource may be used to generate the RNTI:

● the Hyper System Frame Number (HSFN) of the selected UL resource;

● the System Frame Number (SFN) of the selected UL resource;

● the first subframe of the selected UL resource, named as Subsfn;

● the first Resource Block (RB) , first Resource Unit (RU) , or first subcarrier index of the selected UL resource, named as ResourceIndex; or

● the carrier index of the selected UL resource, named as carrier.

Exemplarily, the RNTI may be generated by a linear function using above parameters as variables. For example, the RNTI may be generated using equation below:

RNTI = 1 + A*Subsfn/E + B*SFN/F + C*HSFN/G + D*ResourceIndex/H + P*carrier/Q + I (equation 1)

Note that the order of parameters above is for exemplary purpose only, and may be flexibly organized. For example, the above equation may be re-written as:

RNTI= 1 + D*ResourceIndex/H + A*Subsfn/E + B*SFN/F + C*HSFN/G + P*carrier/Q + I (equation 2)

where, A, B, C, D, and P belong to coefficients and may be integers, including 0, 1, or other values. Exemplarily, each of these parameters may be determined by the maximum value of the its preceding term in the above equation, to avoid potential duplicate RNTIs. For example, B may be the maximum value of (A*Subsfn/E) , note that ( (A*Subsfn/E) is the preceding term of B (or the term including B) in the equation.

where, E, F, G, H, and Q belong to coefficients and may be integers, including 0, 1, or other values. Each of these parameters may be determined by a value range, an upper limit, or a lower limit of the respective variable in the same term, to avoid the redundant value. For example, G may be the maximum value of variable HSFN (i.e., upper limit of HSFN as defined in relevant 3GPP standards, e.g., 1023, or other values, depending on frame structures) . In some example implementations, these parameters may be determined by the maximum possible value of the response window to avoid the redundant value. For example, if the maximum possible value of the response window is 100 ms, E may be set to 100. To clarify, a possible value of a variable is a value within the range of the variable.

Parameter I may be an integer including 0 and other values, it may be determined by the value range of RNTI to avoid the overlap between RNTI and other RNTI. The value range of RNTI may be predefined/preconfigured based on relevant 3GPP standards or practical implementation.

In some example implementations, as a variation of above implementation, UE may generate the RNTI with an additional parameter, Orthogonal Cover Code (OCC) index. That is, UE may generate the RNTI based on time resource, frequency resource, and the OCC index which UE used for transmitting Msg3.

For the selected UL resource from the UL resource pool for Msg3 transmission, the UL resource configuration may include an OCC index, which may be provided by the base station when configuring the UL resource pool, or by the base station via a separate message, such as an RRC message. Exemplarily, the UE may determine a code sequence based on the OCC index and use the code sequence to code the physical channel carrying Msg3.

One or more of the following parameters related to time and frequency resource may be used to generate the RNTI:

● the Hyper System Frame Number (HSFN) of the selected UL resource;

● the System Frame Number (SFN) of the selected UL resource;

● the first subframe of the selected UL resource, named as Subsfn;

● the carrier index of the selected UL resource, named as carrier.

● the OCC index of the selected UL resource, named as OCC

RNTI = 1 + A*Subsfn/E + B*SFN/F + C*HSFN/G + D*ResourceIndex/H + J*OCC/K +P*carrier/Q + I (equation 3)

RNTI= 1 + D*ResourceIndex/H + J*OCC/K + A*Subsfn/E + B*SFN/F + C*HSFN/G + P*carrier/Q + I (equation 4)

where, A, B, C, D, J, and P are integers, including 0, 1, or other values. Exemplarily, each of these parameters may be determined by the maximum value of the its preceding term in the above equation. For example, B may be the maximum value of (A*Subsfn/E) , note that ( (A*Subsfn/E) is the preceding term of B (or the term including B) in the equation.

where, E, F, G, H, K, and Q are integers, including 0, 1, or other values. Each of these parameters may be determined by the value range, the upper limit, or the lower limit of the respective variable in the same term, to avoid the redundant value. For example, G may be the maximum value of variable HSFN (i.e., upper limit of HSFN as defined in relevant 3GPP standards, e.g., 1023, or other values, depending on frame structure) . In some example implementations, these parameters may be determined by the maximum possible value of the response window to avoid the redundant value. For example, if the maximum possible value of the response window is 100 ms, E may be set to 100.

In some example implementations, as a variation of above implementation, UE may further generate the RNTI with another additional parameter, cyclic shift. That is, UE may generate the RNTI based on time resource, frequency resource, the OCC index, and the cyclic shift which UE used for transmitting Msg3.

● the Hyper System Frame Number (HSFN) of the selected UL resource;

● the System Frame Number (SFN) of the selected UL resource;

● the first subframe of the selected UL resource, named as Subsfn;

● the first Resource Block (RB) , first Resource Unit (RU) , or first subcarrier index of the selected UL resource, named as ResourceIndex;

● the carrier index of the selected UL resource, named as carrier;

● the OCC index of the selected UL resource, named as OCC; or

● cyclic shift of the selected UL resource, named as CS.

RNTI = 1 + A*Subsfn/E + B*SFN/F + C*HSFN/G + D*ResourceIndex/H + J*OCC/K +M*CS/N + P*carrier/Q + I (equation 5)

RNTI= 1 + D*ResourceIndex/H + J*OCC/K + M*CS/N + A*Subsfn/E + B*SFN/F +C*HSFN/G + P*carrier/Q + I (equation 6)

where, A, B, C, D, J, M, and P are integers, including 0, 1, or other values. Exemplarily, each of these parameters may be determined by the maximum value of the its preceding term in the above equation. For example, B may be the maximum value of (A*Subsfn/E) , note that ( (A*Subsfn/E) is the preceding term of B (or the term including B) in the equation.

where, E, F, G, H, K, N, and Q are integers, including 0, 1, or other values. Each of these parameters may be determined by the value range, the upper limit, or the lower limit of the respective variable in the same term, to avoid the redundant value. For example, G may be the maximum value of variable HSFN (i.e., upper limit of HSFN as defined in relevant 3GPP standards, e.g., 1023, or other values, depending on frame structure) . In some example implementations, these parameters may be determined by the maximum possible value of the response window to avoid the redundant value. For example, if the maximum possible value of the response window is 100 ms, E may be set to 100.

Embodiment 11: RNTI for Msg3

When UE transmits Msg3 in a random access procedure, an uplink channel, such as the Physical Uplink Shared Channel (PUSCH) , may be used. UE may use an RNTI to address the PUSCH, for example, by using the RNTI to scramble the PUSCH, or Cyclic Redundancy Check (CRC) of the PUSCH.

the one of the following RNTI is used for addressing PUSCH for msg3.

In some example implementations, C-RNTI may be used for addressing msg3. In connected mode, UE may be allocated a C-RNTI. UE may store it, and use it later for addressing Msg3.

In some example implementations, PUR-RNTI may be used for addressing msg3. UE may be allocated a PUR-RNTI via, for example, an RRC message from the base station. UE may store it, and use it later for addressing Msg3.

In some example implementations, a new UE specific RNTI, which is not currently implemented in wireless technology, is introduced in this disclosure. UE may be allocated this new RNTI via, for example, an RRC message, such as an RRC release message from the base station. UE may store it, and use it later for addressing Msg3.

In some example implementations, a common RNTI may be used for addressing Msg3. One or more, or all UEs may use this common RNTI for addressing Msg3.

In some example implementations, a group RNTI (or group common) may be used for addressing Msg3. UE may be allocated a PUR-RNTI via, for example, an RRC message, such as RRC release message from the base station. Multiple UEs may share this same group RNTI. UE may store it, and use it later for addressing Msg3.

Embodiment 12: Contention Resolution Identity

In a contention based access procedure, if there is a contention and Msg3 collides (with other Msg3s simultaneously transmitted by other UEs) , the Msg4 will carry a contention resolution identity to identify a UE and confirms that the contention has been resolved for the identified UE. If UE receives the contention resolution identity, UE may deem the Access procedure successful.

In this embodiment, various types of RNTI that may resolve contention resolution are described. These RNTIs may be UE specific (e.g., dedicated to the UE) and may be used to identify the UE. Therefore, these RNTIs, when used to address the Msg4, may serve as identities for contention resolution, and no further contention resolution identity is needed. For example, these RNTIS can be used to serve two purpose: 1) scrambling Msg4 (or PDCCH of Msg4) ; and 2) contention resolution. That is, if a UE may correctly decode the Msg4 using the RNTI, UE may consider the contention is resolved for it and UE does not need to further check a contention resolution identity. Further, if certain RNTIs are not UE specific (e.g., a group common RNTI) , these RNTIs may be used in a combination with other UE specific information, to form an identity for contention resolution.

In some example implementations, C-RNTI of the UE (allocated to the UE) is used for addressing Msg4. If UE receives a PDCCH (for Msg4) addressed with its assigned C-RNTI, UE may deem the Access procedure successful. That is, if UE is able to decode the PDCCH for Msg4 with its assigned C-RNTI, then the Access procedure is successful.

In some example implementations, PUR-RNTI may be used for addressing Msg4. UE may be allocated a PUR-RNTI via, for example, an RRC message from the base station. If UE receives a PDCCH (for Msg4) addressed with its assigned PUR-RNTI, UE may deem the Access procedure successful.

In some example implementations, a new UE specific RNTI, which is not currently implemented in wireless technology, is introduced in this disclosure. UE may be allocated this new RNTI via, for example, an RRC message, such as an RRC release message from the base station. This new RNTI may differentiate the UE from other UEs. If UE receives a PDCCH (for Msg4) addressed with this new RNTI, UE may deem the Access procedure successful.

In some example implementations, UE may generate an RNTI based on OCC index by using, for example, equations 3-6. If UE receives a PDCCH (for Msg4) addressed with this RNTI, UE may deem the Access procedure successful. Note that UE generated RNTI may be sent to the base station in previous RA steps, such as in Msg3.

In some example implementations, at least a portion of Common Control Channel (CCCH) may be used, in conjunction with a common RNTI or a group RNTI, to serve as a contention resolution identity. For example, the portion of CCCH may include the N leftmost bit and/or the M rightmost bit of the CCCH, where M and N are integers.

Further to the implementations above, the MAC CE of Msg4 (or MAC CE carried in Msg4) may carry the portion of CCCH. When UE receives this MAC CE, and the portion of CCCH (or the whole CCCH) carried in the MAC CE matches the corresponding portion of CCCH (or the whole CCCH) of the UE, UE may deem the Access procedure successful. If a common RNTI, a group RNTI, or another RNTI that is not UE specific is used to address Msg4, CCCH or portion of the CCCH is used as contention resolution identity.

In some example implementations, in stead of using MAC CE of Msg4, the DCI of Msg4 (or DCI associated with Msg) may be used to carry the aforementioned CCCH or a portion of the CCCH.

In some example implementations, instead of using CCCH, a Temporary Mobile Subscriber Identity (TMSI) , or a portion of the TMSI may be used instead. For example, the N leftmost bit and/or the M rightmost bit of the TMSI may be carried by MAC CE and/or DCI of Msg4 (M and N are integers) . If the TMSI matches the TMSI of the UE, or if the portion of the TMSI matches the corresponding portion of the TMSI of the UE, UE may deem the Access procedure successful.

In some example implementations, instead of using TMSI, a Shortend TMSI (S-TMSI) may be similarly used.

In some example implementations, a TMSI may be jointly carried by the PDCCH of the Msg4 and MAC CE of the Msg4. A portion of TMSI may be carried in PDCCH Msg4, (e.g., the N leftmost bit and/or the M rightmost bit of TMSI) , and the remaining portion of the TMSI is carried in MAC CE of the Msg4. If UE receives this MAC CE and DCI, and the carried TMSI matches the TMSI of the UE, UE may deem the Access procedure successful. Therefore, if a common RNTI, a group RNTI, or another RNTI that is not UE specific is used to address Msg4, the TMSI is used as contention resolution identity.

In some example implementations, instead of using TMSI as above, S-TMSI may be used.

Embodiment 13: RNTI in Msg3

In this embodiment, the base station is able to identify the UE which sends a Msg3 in the Access procedure via certain identification information carried in Msg3 (e.g., UE specific RNTI that is dedicated to the UE) . In turn, when base station responses with a Msg4, it may embed the identification information in it, to address the Msg4.

In some example implementations, Msg3 may carry a UE specific RNTI as described in previous embodiments. For example, the UE specific RNTI may include: C-RNTI for the UE; PUR-RNTI for the UE; newly introduced (in this disclosure) UE specific RNTI that may be assigned by the base station; RNTI generated based on: time/frequency domain resource for transmitting Msg3, and/or OCC index uniquely assigned for Msg3 transmission, and/or cyclic shift assigned for Msg3 transmission. The Msg3 may include, for example, an RRCConnectionRequest message; an RRCEarlyDataRequest message; an RRCConnectionResumeRequest message; an RRCSetupRequest message; an Uplink (UL) Non Access Stratum (NAS) Packet Data Unit (PDU) ; or data (payload) in a Data Radio Bearer (DRB) , and the like. In this way, the base station may identify the UE upon receiving the Msg3, and address Msg4 with this same RNTI carried in Msg3.

In some example implementations, a Medium Access Control –Control Element (MAC CE) of the Msg3 may be used to carry the aforementioned UE specific RNTI. When Ue transmits Msg3, which may include RRCConnectionRequest message, or RRCEarlyDataRequest message, the MAC CE carrying the UE specific RNTI is transmitted together.

In some example implementations, the MAC CE mentioned above may also be consider as part of the Msg3.

Embodiment 14: RNTI Allocated by Base Station and Carries in Msg4

In a connected mode, UE will need an identifier, such as a C-RNTI, to serve as an address or identity for messages targeting UE. In this embodiment, such identifier may be integrated into the Access procedure. For example, such identify may be sent to UE via Msg4.

In some example implementations, the base station may allocate the C-RNTI to UE, and use the PDCCH for Msg4 to carry the C-RNTI.

In some example implementations, the base station may allocate the C-RNTI to UE, and use the MAC CE for Msg4 to carry the C-RNTI.

In some example implementations, instead of using base station to allocate a UE specific RNTI (e.g., C-RNTI) for the UE, the RNTI may be generated by the UE side. As described in previous embodiments, UE may generate a UE specific RNTI based on resources used for transmitting Msg3. These resources may include at least one of: time domain resource, frequency domain resource, code domain resource (e.g., OCC index, which is used to determine an OCC sequence used for coding the PUCCH/PUSCH) , or cyclic shift. When transmitting Msg3 to base station, the Msg3 may carry the UE generate RNTI. From base station side, the base station may take the UE generated RNTI, and further passes down the same RNTI to UE via, for example, Msg4. Upon receiving Msg4 (and the RNTI which UE generated earlier) , UE may treat this RNTI as the C-RNTI and save it for later use.

Embodiment 15: Msg3 Retransmission

When the wireless network is congested and/or when UE’s msg3 conflicts with other Msg3s simultaneously sent by other UEs, Msg3 retransmission may need to be performed.

Ideally the base station, upon observing Msg3 collision, may send an instruction to affected UEs for Msg3 retransmission. However, in a contention-based random access procedure, the base station may not be able to distinguish the conflicted msg3, and therefore such instruction for Msg3 retransmission may not be able to be sent. In this embodiment, various methods are described to enable UE to autonomously determine whether a Msg3 retransmission is needed, and UE may take further action to reduce the probability for further Msg3 collision.

In some example implementations, if within a Msg4 response window, UE does not receive a Msg4 as a response for Msg3, UE may perform an autonomous Msg3 retransmission. For example, UE may select the next available transmission occasion (i.e., the nearest available transmission occasion) from a preconfigured UL resource pool (e.g., for Msg3) , and re-transmit the Msg3. Additionally, UE may add associated Hybrid Automatic Repeat Request (HARQ) information to the HARQ entity of the Msg3.

In some example implementations, if within a Msg4 response window, UE does not receive a Msg4 as a response for Msg3, UE may perform an autonomous Msg3 retransmission. In order to reduce the probability for further Msg3 collision, UE may randomly select an UL transmission occasion falling in a time duration. For example, if the Msg4 response window expires in time point A, UE may consider the Msg3 transmission fails at time point A. Then within a time duration starting from time point A, UE may randomly select an UL transmission occasion to retransmit Msg3. Refer to FIG. 10 for an illustration on this example. In FIG. 10, initial Msg3 transmission is determined to be failed at time point A (after the Msg4 response window expires) . Starting from time point A, there is a duration 1010 for selecting an UL resource (or UL transmission occasion) . As shown in FIG. 10, there are 4 UL transmission occasions: 1002, 1004, 1006, and 1008. UE may randomly select an UL transmission occasion and use it for Msg3 retransmission.

For another example, starting from the UL transmission occasion that is closest to time point A, UE may randomly select an UL transmission occasion from the next N UL transmission occasions, and use the selected UL transmission occasion to retransmit Msg3. The time duration and N may be predefined, or configured by the base station via, for example, an RRC message, or a broadcast message. Referring to FIG. 10, assuming N=3, then starting from time point A, the next 3 UL transmission occasions (i.e., 1002, 1004, 1006) are available for selection, and UE may randomly select an UL transmission occasion from them.

Embodiment 16: Msg3 Retransmission Delay

In an access procedure (e.g., with two step Msg3 and Msg4) , when multiple UEs attempt to transmit Msg3 during the access procedure simultaneously, collisions may occur, which cause interference and overlapping signals. The base station may have difficulty decode the collided messages. Collision has to be addressed properly, to prevent congestion condition as multiple UEs will keep competing for uplink resources, which may cause further UE access delay.

In this embodiment, various methods are described, to mitigate collisions via improved Msg3 retransmissions coordination. Via these methods, more efficient resource utilization and minimized latency may be achieved.

At a high level, if msg3 collisions and/or uplink congestion are overserved, the base station may indicate UE to delay re-attempting the access, and the base station may orchestra the delay access.

In some example implementations, the base station may send a backoff indication via the PDCCH for Msg4. If UE receives this indication from the PDCCH, UE may delay the random access, that is, instead of re-transmitting the Msg3, UE will add a delay to the retransmission.

In some example implementations, the base station may send a backoff indication via the MAC CE for Msg4. If UE receives this indication from the MAC CE, UE may delay the random access.

In some example implementations, the base station may further send a delay time (or wait time) via the PDCCH for Msg4. The UE may then delay the random access by the indicated delay time. The delay time may be in the form of a duration, or a number of transmission occasion presented in the UL resource pool, and the like. For example, the UE may wait for a duration as indicated, or skip a number of transmission occasions as indicated. Note that the UE may be configured with a UL resource pool by the base station (e.g., via a UL resource configuration list, with each UL resource configuration in the list corresponding to a UL resource) .

In some example implementations, the base station may similarly send a delay time (or wait time) via the MAC CE for Msg4.

In some example implementations, UE may delay (postpone) the access by a duration selected randomly. A maximum duration may be predefined, or preconfigured by the base station via, for example, an RRC message or a broadcast message. The maximum duration may also be carried in the PDCCH or MAC CE for Msg4. UE may select a random value within the maximum duration as the delay value. Alternatively, UE may skip a random number of transmit contentions, to postpone the random access. The maximum skipped transmit contentions may be predefined, or preconfigured by the base station via, for example, an RRC message or a broadcast message. The maximum skipped transmit contentions may also be carried in the PDCCH or MAC CE for Msg4.

Note that above implementations may be combined. For example, when UE receives a backoff indication, UE may postpone the next Msg3 attempt by a duration as pre-configured or indicated by the base station, or UE may postpone the next Msg3 attempt by a random delay, or UE may skip a number of transmission occasions as pre-configured or indicated by the base station.

Embodiment 17: Msg3 Failure Handling

In this embodiments, various methods for handling Msg3 failure are described. the transmission of Msg3 may be contention based. For example, multiple UEs may simultaneously transmit their respective Msg3s using a shared resource that is configured by the UL resource configuration. In this embodiment, various thresholds are used for determination of various types of failures. These thresholds may be configured by the base station via, for example, an RRC message or a broadcast message.

In some example implementations, when a Medium Access Control (MAC) layer of the UE detects a Msg3 transmission failure, or considers the Msg3 transmission fails, the MAC layer may indicate the failure to the RRC layer of the UE.

In some example implementations, if the retransmission number for Msg3 exceeds a threshold, MAC layer considers contention based Msg3 fails.

In some example implementations, if the retransmission exceeds a time length threshold, MAC layer of the UE considers contention based msg3 fails. The time length threshold may be configured by the base station via, for example, an RRC message or a broadcast message.

In some example implementations, if MAC layer of the UE considers contention based msg3 fails, MAC layer may indicate the failure to the RRC layer of the UE. For example, if the number that UE performs transmission of msg3 exceeds a threshold or the retransmission exceeds a time length threshold, MAC layer may indicate the failure to the RRC layer of the UE.

In some example implementations, if RRC layer receives the indication about the failure of transmission of contention based msg3, RRC layer considers contention based msg3 fails.

In some example implementations, if RRC layer receives the indication about the failure of transmission of contention based msg3, RRC could trigger a re-transmission of contention based msg3.

In some example implementations, if the number that RRC trigger the transmission of contention based msg3 exceeds a threshold, RRC considers contention based msg3 fails.

In some example implementations, if the duration of an RRC layer triggered contention based msg3 transmission exceeds a threshold, RRC considers contention based msg3 fails. That is, from the start of RRC layer triggered msg3 transmission, there is a time window (e.g., 10 seconds) for trying the Msg3 transmission and possible re-transmission. If the Msg3 transmission is not successful within the time window, RRC layer may consider the msg3 transmission fails.

In some example implementations, if RRC layer considers contention based msg3 fails, RRC could indicate Non Access Stratum (NAS) the RRC failure.

In some example implementations, if RRC layer considers contention based msg3 fails, RRC layer may discard the UL resource pool, which is configured to provide UL resource for UL transmission (such as Msg3 transmission) .

In some example implementations, if RRC layer considers contention based msg3 fails, and the condition of Preconfigured Uplink Resource (PUR) is satisfied, RRC layer may trigger a PUR procedure, to use PUR resource to transmit the Msg3.

In some example implementations, if RRC layer considers contention based msg3 fails, and the condition of EDT/CG-SDT is satisfied, RRC layer may trigger an Early Data Transmission /Configured Grant –Small Data Transmission (EDT/CG-SDT) procedure.

In this disclosure, embodiments are described individually merely for the sake of easy understanding and description. These embodiments are for exemplary purpose and may be combined in any order, if there is no conflict. For example, embodiments handling Msg3 may be combined with embodiments handling Msg4 to form a new embodiment, as Msg4 follows Msg3 in an access procedure. Embodiments handling message error detection and/or re-transmission may be combined with their respective embodiments for handling the message. Embodiments handling RNTIs may be combined with embodiments handling Msg3 and/or Msg4. In this disclosure, a message may be addressed by an RNTI, for example, the PDCCH/PDSCH/PUCCH/PUSCH may be scrambled by the RNTI for addressing purpose. A message may also carry an RNTI as payload data, so the RNTI may be sent to a receipient.

The description and accompanying drawings above provide specific example embodiments and implementations. The described subject matter may, however, be embodied in a variety of different forms and, therefore, covered or claimed subject matter is intended to be construed as not being limited to any example embodiments set forth herein. A reasonably broad scope for claimed or covered subject matter is intended. Among other things, for example, subject matter may be embodied as methods, devices, components, systems, or non-transitory computer-readable media for storing computer codes. Accordingly, embodiments may, for example, take the form of hardware, software, firmware, storage media or any combination thereof. For example, the method embodiments described above may be implemented by components, devices, or systems including memory and processors by executing computer codes stored in the memory.

Throughout the specification and claims, terms may have nuanced meanings suggested or implied in context beyond an explicitly stated meaning. Likewise, the phrase “in one embodiment/implementation” as used herein does not necessarily refer to the same embodiment and the phrase “in another embodiment/implementation” as used herein does not necessarily refer to a different embodiment. It is intended, for example, that claimed subject matter includes combinations of example embodiments in whole or in part.

In general, terminology may be understood at least in part from usage in context. For example, terms, such as “and” , “or” , or “and/or, ” as used herein may include a variety of meanings that may depend at least in part on the context in which such terms are used. Typically, “or” if used to associate a list, such as A, B or C, is intended to mean A, B, and C, here used in the inclusive sense, as well as A, B or C, here used in the exclusive sense. In addition, the term “one or more” as used herein, depending at least in part upon context, may be used to describe any feature, structure, or characteristic in a singular sense or may be used to describe combinations of features, structures or characteristics in a plural sense. Similarly, terms, such as “a, ” “an, ” or “the, ” may be understood to convey a singular usage or to convey a plural usage, depending at least in part upon context. In addition, the term “based on” may be understood as not necessarily intended to convey an exclusive set of factors and may, instead, allow for the existence of additional factors not necessarily expressly described, again, depending at least in part on context.

Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present solution should be or are included in any single implementation thereof. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present solution. Thus, discussions of the features and advantages, and similar language, throughout the specification may, but do not necessarily, refer to the same embodiment.

Furthermore, the described features, advantages and characteristics of the present solution may be combined in any suitable manner in one or more embodiments. One of ordinary skill in the relevant art will recognize, in light of the description herein, that the present solution may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the present solution.

Claims

A method for wireless communication, performed by a wireless device, comprising:

transmitting, to a network node, a Msg3 of an access procedure, the Msg3 being a start of the access procedure.
The method of claim 1, wherein the Msg3 is characterized by at least one of following:

the Msg3 is addressed by a Radio Network Temporary Identifier (RNTI) ;

the Msg3 carries the RNTI; or

a Medium Access Control –Control Element (MAC CE) of the Msg3 carries the RNTI.
The method of claim 1, wherein the Msg3 comprises at least one of:

an RRCConnectionRequest message;

an RRCEarlyDataRequest message;

an RRCConnectionResumeRequest message;

an RRCS-etupRequest message;

an Uplink (UL) Non Access Stratum (NAS) Packet Data Unit (PDU) ; or

a data in a Data Radio Bearer (DRB) .
The method of claim 1, wherein at least a portion of a physical uplink channel carrying the Msg3 is scrambled by an RNTI.
The method of any one of claims 1-4, wherein the RNTI is a UE specific RNTI and is dedicated to the wireless device.
The method of any one of claims 1-4, wherein the RNTI comprises at least one of:

a Cell-RNTI (C-RNTI) which is allocated by the network node;

a Pre-configured Uplink Resource RNTI (PUR-RNTI) which is allocated by the network node;

a first RNTI dedicated to the wireless device and allocated by the network node;

a second RNTI dedicated to the wireless device and generated by the wireless device; or

a common RNTI that is shared by all wireless devices served by the network node, or shared by a group of wireless devices served by the network node.
The method of claim 6, wherein the wireless device is configured with a UL resource pool used for transmitting an Msg3 of the access procedure, the method further comprising:

generating the second RNTI based on at least one of: a time domain resource of a UL resource selected from the UL resource pool used for transmitting the Msg3; a frequency domain resource of the UL resource; a code domain resource of the UL resource; or a cyclic shift of the UL resource.
The method of claim 6, wherein the wireless device is configured with a UL resource pool used for transmitting an Msg3 of the access procedure, the method further comprising:

generating the second RNTI based on a linear function, the linear function being based at least one of: a time domain resource of a UL resource selected from the UL resource pool used for transmitting the Msg3; a frequency domain resource of the UL resource; a code domain resource of the UL resource; or a cyclic shift of the UL resource.
The method of claim 8, wherein the linear function comprises:
RNTI = 1 + A*Subsfn/E + B*SFN/F + C*HSFN/G + D*ResourceIndex/H +
P*carrier/Q + I,

wherein: HSFN, SFN, subsfn, ResourceIndex, and carrier are variables in the linear function, HSFN is a Hyper System Frame Number (HSFN) of the UL resource, SFN is a System Frame Number (SFN) of the UL resource, Subsfn is a first subframe in a system frame identified by the SFN, ResourceIndex comprises one of: a first Resource Block (RB) , a first Resource Unit (RU) , or a first subcarrier index of the UL resource; carrier is a carrier index of the selected UL resource; each of A, B, C, D, and P is determined based on its preceding term in the linear function; and each of E, F, G, H, and Q is determined based on a respective variable in its corresponding term.
The method of claim 8, wherein the linear function comprises:
1 + A*Subsfn/E + B*SFN/F + C*HSFN/G + D*ResourceIndex/H + J*OCC/K +
P*carrier/Q + I,

wherein: HSFN, SFN, subsfn, ResourceIndex, OCC, and carrier are variables in the linear function, HSFN is a Hyper System Frame Number (HSFN) of the UL resource, SFN is a System Frame Number (SFN) of the UL resource, Subsfn is a first subframe in a system frame identified by the SFN, ResourceIndex comprises one of: a first Resource Block (RB) ; a first Resource Unit (RU) ; or a first subcarrier index of the UL resource, OCC is an Orthogonal Cover Code (OCC) index of the UL resource, carrier is a carrier index of the selected UL resource; each of A, B, C, D, J, and P is determined based on its preceding term in the linear function; and each of E, F, G, H, K, and Q is determined based on a respective variable in its corresponding term.
The method of claim 8, wherein the linear function comprises:
RNTI = 1 + A*Subsfn/E + B*SFN/F + C*HSFN/G + D*ResourceIndex/H +
J*OCC/K + M*CS/N + P*carrier/Q + I,

wherein: HSFN, SFN, subsfn, ResourceIndex, OCC, CS, and carrier are variables in the linear function, HSFN is a Hyper System Frame Number (HSFN) of the UL resource, SFN is a System Frame Number (SFN) of the UL resource, Subsfn is a first subframe in a system frame identified by the SFN, ResourceIndex comprises one of: a first Resource Block (RB) ; a first Resource Unit (RU) ; or a first subcarrier index of the UL resource, OCC is an Orthogonal Cover Code (OCC) index of the UL resource, CS is a cyclic shift of the UL resource, carrier is a carrier index of the selected UL resource; each of A, B, C, D, J, M, and P is determined based on its preceding term in the linear function; and each of E, F, G, H, K, N, and Q is determined based on a respective variable in its corresponding term.
The method of claim 6, wherein at least one of the C-RNTI; the PUR-RNTI; the first RNTI; or the second RNTI is sent to the wireless device via a Radio Resource Control (RRC) message.
The method of any one of claims 1-5, further comprising:

in response to a Msg4 not being received within a Msg4 response window, retransmitting the Msg3, wherein the Msg4 is a response to the Msg3 and carries contention resolution information.
The method of claim 13, wherein retransmitting the Msg3 comprises:

retransmitting the Msg3 using a next available Uplink (UL) resource from a pre-configured UL resource pool that is closest to a current time.
The method of claim 14, wherein a Hybrid Automatic Repeat Request (HARQ) information associated with the retransmitting is carried in an HARQ entity associated with the Msg3.
The method of claim 13, wherein:

the wireless device is configured with an UL resource pool which comprises multiple UL transmission occasions;

retransmitting the Msg3 comprises randomly selecting from the UL resource pool, an UL transmission occasion falling into a retransmission window, wherein the retransmission window has a starting point and a duration, wherein:

the starting point comprises at least one of:

a first time point that the Msg4 response window ends; or

a second time point which is a transmission occasion closest to the first time point; and

the duration is configured by the network node via at least one of: an RRC message or a broadcast message.
The method of any one of claims 1-5, further comprising receiving, from the network node, a Msg4 as a response to the Msg3, the Msg4 comprising at least one of:

a backoff indicator indicating the wireless device to postpone a retransmission of the Msg3; or

a delay time window associated with postponing the retransmission of the Msg3.
The method of claim 17, wherein each of the backoff indicator and the delay time window is carried in at least one of:

a Physical Downlink Control Channel (PDCCH) of the Msg4; or

a MAC CE of the Msg4.
The method of claim 17, wherein the delay time window is represented by one of:

a time duration; or

a number of UL transmission occasions.
The method of claim 19, further comprising:

retransmitting the Msg3 with a delay indicated by the time duration; or

retransmitting the Msg3 after skipping the number of UL transmission occasions, where each of the UL transmission occasions is configured by an UL resource pool.
The method of claim 19, further comprising:

randomly selecting an UL transmission occasion from an UL resource pool within the delay time window; and

retransmitting the Msg3 using the randomly selected UL transmission occasion.
The method of any one of claims 1-5, further comprising:

in response to at least one of: a number of Msg3 retransmissions for the Msg3 at a Medium Access Control (MAC) layer of the wireless device exceeding a first retransmission number threshold; or a duration for a Msg3 retransmission process at the MAC layer exceeding a first retransmission duration threshold, determining, by the MAC layer, that the Msg3 retransmission process at the MAC layer fails; and

indicating, by the MAC layer to a Radio Resource Control (RRC) layer of the wireless device, that the Msg3 retransmission process at the MAC layer fails.
The method of claim 22, each of the retransmission number threshold and the retransmission duration threshold is sent by the network node via least one of:

an RRC message; or

a broadcast message.
The method of claim 22, further comprising:

in response to receiving an indication that the Msg3 retransmission process at the MAC layer fails, triggering, by the RRC layer, retransmitting the Msg3.
The method of claim 24, further comprising:

in response to at least one of: a number of Msg3 retransmissions for the Msg3 at RRC layer exceeding a second retransmission number threshold; or a duration for a Msg3 retransmission process at the RRC layer exceeding a second retransmission duration threshold, determining, by the RRC layer, that the Msg3 retransmission process at the RRC layer fails.
The method of claim 25, further comprising at least one of:

indicating, by the MAC layer to a Non Access Stratum (NAS) layer of the wireless device, that that the Msg3 retransmission process at the RRC layer fails;

discarding a pre-configured UL resource pool associated with random access;

in response to a condition for Early Data Transmission (EDT) being met, switching to an EDT procedure; or

in response to a condition for Configured Grant -Small Data Transmission (CG-SDT) being met, switching to a CG-SDT procedure.
A method for wireless communication, performed by a network node, comprising:

receiving, from a wireless device, a Msg3 of an access procedure for establishing a connection with the network node, the Msg3 being a start of the access procedure.
The method of claim 27, wherein the Msg3 is characterized by at least one of following:

the Msg3 is addressed by a Radio Network Temporary Identifier (RNTI) ;

the Msg3 carries the RNTI; or

a Medium Access Control –Control Element (MAC CE) of the Msg3 carries the RNTI.
The method of claim 27, wherein the Msg3 comprises at least one of:

an RRCConnectionRequest message;

an RRCEarlyDataRequest message;

an RRCConnectionResumeRequest message;

an RRCSetupRequest message;

an Uplink (UL) Non Access Stratum (NAS) Packet Data Unit (PDU) ; or

a data in a Data Radio Bearer (DRB) .
The method of claim 27, wherein at least a portion of a physical uplink channel carrying the Msg3 is scrambled by an RNTI.
The method of any one of claims 27-30, wherein the RNTI is a UE specific RNTI and is dedicated to the wireless device.
The method of any one of claims 27-30, wherein the RNTI comprises at least one of:

a Cell-RNTI (C-RNTI) which is allocated by the network node;

a Pre-configured Uplink Resource RNTI (PUR-RNTI) which is allocated by the network node;

a first RNTI dedicated to the wireless device and allocated by the network node;

a second RNTI dedicated to the wireless device and generated by the wireless device; or

a common RNTI that is shared by all wireless devices served by the network node, or shared by a group of wireless devices served by the network node.
The method of claim 32, wherein at least one of the C-RNTI; the PUR-RNTI; the first RNTI; or the second RNTI is sent to the wireless device via a Radio Resource Control (RRC) message.
The method of any one of claims 27-31, further comprising transmitting, to the wireless device, a Msg4 as a response to the Msg3, the Msg4 comprising at least one of:

a backoff indicator indicating the wireless device to postpone a retransmission of the Msg3; or

a delay time window associated with postponing the retransmission of the Msg3.
The method of claim 34, wherein each of the backoff indicator and the delay time window is carried in at least one of:

a Physical Downlink Control Channel (PDCCH) of the Msg4; or

a MAC CE of the Msg4.
The method of claim 34, wherein the delay time window is represented by one of:

a time duration; or

a number of UL transmission occasions.
A method for wireless communication, performed by a wireless device, comprising:

receiving, from a network node, a Msg4 as part of an access procedure for establishing a connection between the wireless device and the network node, the access procedure starting with a Msg3.
The method of claim 37, wherein the Msg4 is characterized by at least one of following:

the Msg4 is addressed by a Radio Network Temporary Identifier (RNTI) ;

the Msg4 carries the RNTI;

a Medium Access Control –Control Element (MAC CE) of the Msg4 carries the RNTI; or

a Physical Downlink Control Channel (PDCCH) of the Msg4 carries the RNTI.
The method of claim 37, wherein the Msg4 comprises at least one of:

an RRC message;

a Downlink Control Information (DCI) message; or

a MAC CE.
The method of claim 37, wherein at least a portion of a Physical Downlink Control Channel (PDCCH) carrying the Msg4 is scrambled by an RNTI.
The method of any one of claims 37-40, wherein the RNTI is a UE specific RNTI and is dedicated to the wireless device.
The method of any one of claims 37-40, wherein the Msg4 carries an RNTI or the Msg4 is addressed by the RNTI, and wherein the RNTI comprises at least one of:

a Cell-RNTI (C-RNTI) which is allocated by the network node;

a Pre-configured Uplink Resource RNTI (PUR-RNTI) which is allocated by the network node;

a first RNTI dedicated to the wireless device and allocated by the network node;

a second RNTI dedicated to the wireless device and generated by the wireless device; or

a common RNTI that is shared by all wireless devices served by the network node, or shared by a group of wireless devices served by the network node.
The method of claim 42, wherein at least one of the C-RNTI; the PUR-RNTI; the first RNTI; or the second RNTI is sent to the wireless device via a Radio Resource Control (RRC) message.
The method of claim 42, wherein the wireless device is configured with a UL resource pool used for transmitting an Msg3 of the access procedure, and wherein the second RNTI is generated based on at least one of: a time domain resource of a UL resource selected from the UL resource pool used for transmitting the Msg3; a frequency domain resource of the UL resource; a code domain resource of the UL resource; or a cyclic shift of the UL resource.
The method of claim 42, wherein the wireless device is configured with a UL resource pool used for transmitting an Msg3 of the access procedure, and wherein the second RNTI is generated based on a linear function, the linear function being based at least one of: a time domain resource of a UL resource selected from the UL resource pool used for transmitting the Msg3; a frequency domain resource of the UL resource; a code domain resource of the UL resource; or a cyclic shift of the UL resource.
The method of claim 45, wherein the linear function comprises:
RNTI = 1 + A*Subsfn/E + B*SFN/F + C*HSFN/G + D*ResourceIndex/H +
P*carrier/Q + I,

wherein: HSFN, SFN, subsfn, ResourceIndex, and carrier are variables in the linear function, HSFN is a Hyper System Frame Number (HSFN) of the UL resource, SFN is a System Frame Number (SFN) of the UL resource, Subsfn is a first subframe in a system frame identified by the SFN, ResourceIndex comprises one of: a first Resource Block (RB) , a first Resource Unit (RU) , or a first subcarrier index of the UL resource; carrier is a carrier index of the selected UL resource; each of A, B, C, D, and P is determined based on its preceding term in the linear function; and each of E, F, G, H, and Q is determined based on a respective variable in its corresponding term.
The method of claim 45, wherein the linear function comprises:
1 + A*Subsfn/E + B*SFN/F + C*HSFN/G + D*ResourceIndex/H + J*OCC/K +
P*carrier/Q + I,

wherein: HSFN, SFN, subsfn, ResourceIndex, OCC, and carrier are variables in the linear function, HSFN is a Hyper System Frame Number (HSFN) of the UL resource, SFN is a System Frame Number (SFN) of the UL resource, Subsfn is a first subframe in a system frame identified by the SFN, ResourceIndex comprises one of: a first Resource Block (RB) ; a first Resource Unit (RU) ; or a first subcarrier index of the UL resource, OCC is an Orthogonal Cover Code (OCC) index of the UL resource, carrier is a carrier index of the selected UL resource; each of A, B, C, D, J, and P is determined based on its preceding term in the linear function; and each of E, F, G, H, K, and Q is determined based on a respective variable in its corresponding term.
The method of claim 45, wherein the linear function comprises:
RNTI = 1 + A*Subsfn/E + B*SFN/F + C*HSFN/G + D*ResourceIndex/H +
J*OCC/K + M*CS/N + P*carrier/Q + I,

wherein: HSFN, SFN, subsfn, ResourceIndex, OCC, CS, and carrier are variables in the linear function, HSFN is a Hyper System Frame Number (HSFN) of the UL resource, SFN is a System Frame Number (SFN) of the UL resource, Subsfn is a first subframe in a system frame identified by the SFN, ResourceIndex comprises one of: a first Resource Block (RB) ; a first Resource Unit (RU) ; or a first subcarrier index of the UL resource, OCC is an Orthogonal Cover Code (OCC) index of the UL resource, CS is a cyclic shift of the UL resource, carrier is a carrier index of the selected UL resource; each of A, B, C, D, J, M, and P is determined based on its preceding term in the linear function; and each of E, F, G, H, K, N, and Q is determined based on a respective variable in its corresponding term.
The method of claim 42, wherein the Msg4 is indicative of whether an access contention is resolved, the method further comprising:

in response to a RNTI comprising at least one of: the C-RNTI, the PUR-RNTI, the first RNTI, or the second RNTI, determining that the access contention is resolved.
The method of claim 49, wherein:

the Msg4 is a response to a Msg3 as part of the access procedure; and

the first RNTI is determined by the wireless device based on an OCC index of an UL resource used for transmitting the Msg3.
The method of claim 42, wherein:

the Msg4 carries a MAC CE, the MAC CE carrying at least a portion of a Common Control Channel (CCCH) ; and

in response to the at least the portion of the CCCH carried in the MAC CE matching a corresponding portion of a CCCH of the wireless device, determining that an access contention is resolved.
The method of claim 51, wherein the at least a portion of the CCCH comprises at least one of: N leftmost bits of the CCCH; or M rightmost bits of the CCCH, M and N being integers.
The method of claim 42, wherein:

the Msg4 carries a MAC CE, the MAC CE carrying at least a portion of a Temporary Mobile Subscriber Identity (TMSI) , or at least a portion of a Shortened Temporary Mobile Subscriber Identity (S-TMSI) ; and

in response to the at least the portion of the TMSI carried in the MAC CE matching a corresponding portion of a TMSI of the wireless device, in response to the at least the portion of the S-TMSI carried in the MAC CE matching a corresponding portion of a S-TMSI of the wireless device, determining that an access contention is resolved.
The method of claim 42, wherein:

the Msg4 comprises a DCI or the Msg4 is associated with the DCI, the DCI carrying at least a portion of a TMSI, or at least a portion of an S-TMSI; and

in response to the at least the portion of the TMSI carried in the DCI matching a corresponding portion of a TMSI of the wireless device, in response to the at least the portion of the S-TMSI carried in the DCI matching a corresponding portion of a S-TMSI of the wireless device, determining that an access contention is resolved.
The method of claim 42, wherein:

the Msg4 carries a MAC CE, the MAC CE and a PDCCH of the Msg4 jointly carry a TMSI, or as S-TMSI; and

in response to the TMSI jointly carried in the MAC CE and the PDCCH matching a TMSI of the wireless device, or in response to the S-TMSI jointly carried in the MAC CE and the PDCCH matching a TMSI of the wireless device, determining that an access contention is resolved.
The method of any one of claims 37-40, wherein the RNTI is generated by the wireless device and is dedicated to the wireless device, the method further comprising:

in response to receiving the Msg4, storing the RNTI as a C-RNTI of the wireless device.
A method for wireless communication, performed by a network node, comprising:

transmitting, to a wireless device, a Msg4 as part of an access procedure for establishing a connection between the wireless device and the network node, the access procedure starting with a Msg3.
The method of claim 57, wherein the Msg4 is characterized by at least one of following:

the Msg4 is addressed by a Radio Network Temporary Identifier (RNTI) ;

the Msg4 carries the RNTI;

a Medium Access Control –Control Element (MAC CE) of the Msg4 carries the RNTI; or

a Physical Downlink Control Channel (PDCCH) of the Msg4 carries the RNTI.
The method of claim 57, wherein the Msg4 comprises at least one of:

an RRC message;

a Downlink Control Information (DCI) message; or

a MAC CE.
The method of claim 57, wherein at least a portion of a Physical Downlink Control Channel (PDCCH) carrying the Msg4 is scrambled by an RNTI.
The method of any one of claims 57-60, wherein the RNTI is a UE specific RNTI and is dedicated to the wireless device.
The method of any one of claims 57-60, wherein the Msg4 carries an RNTI or the Msg4 is addressed by the RNTI, and wherein the RNTI comprises at least one of:

a Cell-RNTI (C-RNTI) which is allocated by the network node;

a Pre-configured Uplink Resource RNTI (PUR-RNTI) which is allocated by the network node;

a first RNTI dedicated to the wireless device and allocated by the network node;

a second RNTI dedicated to the wireless device and generated by the wireless device; or

a common RNTI that is shared by all wireless devices served by the network node, or shared by a group of wireless devices served by the network node.
The method of claim 62, further comprising transmitting, to the wireless device via an RRC message, at least one of: the C-RNTI; the PUR-RNTI; the first RNTI; or the second RNTI.
The method of claim 62, wherein the Msg4 is indicative of whether an access contention is resolved.
A device for wireless communication comprising a memory for storing computer instructions and a processor in communication with the memory, wherein, when the processor executes the computer instructions, the processor is configured to implement a method in any one of claims 1-64.
A computer program product comprising a non-transitory computer-readable program medium with computer code stored thereupon, the computer code, when executed by one or more processors, causing the one or more processors to implement a method of any one of claims 1-64.