WO2024118223A1

WO2024118223A1 - Variable subchannel sizes in sidelink communication

Info

Publication number: WO2024118223A1
Application number: PCT/US2023/037223
Authority: WO
Inventors: Stelios STEFANATOS; Chih-Hao Liu; Gabi Sarkis; Giovanni Chisci
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2022-12-02
Filing date: 2023-11-13
Publication date: 2024-06-06
Anticipated expiration: 2025-06-02

Abstract

Wireless communications systems, apparatuses, and methods are provided. A method of wireless communication performed by a first sidelink user equipment (UE) includes selecting first resources from a resource pool; selecting second resources from the resource pool; jointly mapping the first resources and the second resources to a same size of nominal resources; transmitting, to a second sidelink UE using the first resources, a first sidelink communication including a transport block (TB) and an indicator indicating the second resources; and transmitting, to the second sidelink UE using the second resources, a second sidelink communication including the TB, wherein a size of the TB is based on at least the size of the nominal resources.

Description

VARIABLE SUBCHANNEL SIZES IN SIDELINK COMMUNICATION

CROSS-REFERENCE TO A RELATED APPLICATION

[0001] The present application claims priority to and the benefit of Greek Patent Application No. 20220101002, filed December 2, 2022, the disclosure of which is referenced herein in its entirety as if fully set forth below and for all applicable purposes.

TECHNICAL FIELD

[0002] This application relates to wireless communication systems, and more particularly, to variable subchannel sizes in sidelink wireless communication systems.

INTRODUCTION

[0003] Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). A wireless multiple-access communications system may include a number of base stations (BSs), each simultaneously supporting communications for multiple communication devices, which may be otherwise known as user equipment (UE).

[0004] To meet the growing demands for expanded mobile broadband connectivity, wireless communication technologies are advancing from the LTE technology to a next generation new radio (NR) technology. For example, NR is designed to provide a lower latency, a higher bandwidth or throughput, and a higher reliability than LTE. NR is designed to operate over a wide array of spectrum bands, for example, from low- frequency bands below about 1 gigahertz (GHz) and mid-frequency bands from about 1 GHz to about 6 GHz, to high-frequency bands such as millimeter wave (mmWave) bands. NR is also designed to operate across different spectrum types, from licensed spectrum to unlicensed and shared spectrum. Spectrum sharing enables operators to opportunistically aggregate spectrums to dynamically support high-bandwidth services. Spectrum sharing may extend the benefit of NR technologies to operating entities that may not have access to a licensed spectrum. [0005] NR may support various deployment scenarios to benefit from the various spectrums in different frequency ranges, licensed and/or unlicensed, and/or coexistence of the LTE and NR technologies. For example, NR may be deployed in a standalone NR mode over a licensed and/or an unlicensed band or in a dual connectivity mode with various combinations of NR and LTE over licensed and/or unlicensed bands.

[0006] In a wireless communication network, a BS may communicate with a UE in an uplink direction and a downlink direction. Sidelink was introduced in LTE to allow a UE to send data to another UE (e.g., from one vehicle to another vehicle) without tunneling through the BS and/or an associated core network. The LTE sidelink technology has been extended to provision for device-to-device (D2D) communications, vehicle-to-everything (V2X) communications, and/or cellular vehicle-to-everything (C- V2X) communications. Similarly, NR may be extended to support sidelink communications, D2D communications, V2X communications, and/or C-V2X over licensed frequency bands and/or unlicensed frequency bands (e.g., shared frequency bands).

BRIEF SUMMARY OF SOME EXAMPLES

[0007] The following summarizes some aspects of the present disclosure to provide a basic understanding of the discussed technology. This summary is not an extensive overview of all contemplated features of the disclosure and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure in summary form as a prelude to the more detailed description that is presented later.

[0008] In an aspect of the disclosure, a method of wireless communication performed by a first sidelink user equipment (UE) may include selecting first resources from a resource pool; selecting second resources from the resource pool; jointly mapping the first resources and the second resources to a same size of nominal resources; transmitting, to a second sidelink UE using the first resources, a first sidelink communication including a transport block (TB) and an indicator indicating the second resources; and transmitting, to the second sidelink UE using the second resources, a second sidelink communication including the TB, wherein a size of the TB is based on at least the size of the nominal resources. [0009] In an additional aspect of the disclosure, a method of wireless communication performed by a first sidelink user equipment (UE) may include jointly mapping first resources and second resources to a same size of nominal resources; receiving, from a second sidelink UE using the first resources, a first sidelink communication including a transport block (TB) and an indicator indicating the second resources; and receiving, from the second sidelink UE using the second resources, a second sidelink communication including the TB, wherein a size of the TB is based on at least the size of the nominal resources.

[0010] In an additional aspect of the disclosure, a first sidelink user equipment (UE) may include a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, wherein the first sidelink UE is configured to select first resources from a resource pool; select second resources from the resource pool; jointly map the first resources and the second resources to a same size of nominal resources; transmit, to a second sidelink UE using the first resources, a first sidelink communication including a transport block (TB) and an indicator indicating the second resources; and transmit, to the second sidelink UE using the second resources, a second sidelink communication including the TB, wherein a size of the TB is based on at least the size of the nominal resources.

[0011] In an additional aspect of the disclosure, a first sidelink user equipment (UE) may include a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, wherein the first sidelink UE is configured to jointly map first resources and second resources to a same size of nominal resources; receive, from a second sidelink UE using the first resources, a first sidelink communication including a transport block (TB) and an indicator indicating the second resources; and receive, from the second sidelink UE using the second resources, a second sidelink communication including the TB, wherein a size of the TB is based on at least the size of the nominal resources.

[0012] Other aspects, features, and instances of the present invention will become apparent to those of ordinary skill in the ail, upon reviewing the following description of specific, exemplary instances of the present invention in conjunction with the accompanying figures. While features of the present invention may be discussed relative to certain aspects and figures below, all instances of the present invention may include one or more of the advantageous features discussed herein. In other words, while one or more instances may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various instances of the invention discussed herein. In similar fashion, while exemplary aspects may be discussed below as device, system, or method instances it should be understood that such exemplary instances may be implemented in various devices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 illustrates a wireless communication network according to some aspects of the present disclosure.

[0014] FIG. 2 illustrates an example disaggregated base station architecture according to some aspects of the present disclosure.

[0015] FIG. 3 illustrates a frequency interlace across multiple resource block sets according to some aspects of the present disclosure.

[0016] FIG. 4 illustrates frequency interlaces across a single resource block set according to some aspects of the present disclosure.

[0017] FIG. 5 is a signal flow diagram of a communication method according to some aspects of the present disclosure.

[0018] FIG. 6 is a block diagram of an exemplary user equipment (UE) according to some aspects of the present disclosure.

[0019] FIG. 7 is a block diagram of an exemplary network unit according to some aspects of the present disclosure.

[0020] FIG. 8 is a flow diagram of a communication method according to some aspects of the present disclosure.

[0021] FIG. 9 is a flow diagram of a communication method according to some aspects of the present disclosure.

DETAILED DESCRIPTION

[0022] The detailed description set forth below, in connection with the appended drawings, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

[0023] This disclosure relates generally to wireless communications systems, also referred to as wireless communications networks. In various instances, the techniques and apparatus may be used for wireless communication networks such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single-carrier FDMA (SC-FDMA) networks, LTE networks, GSM networks, 5^th Generation (5G) or new radio (NR) networks, as well as other communications networks. As described herein, the terms “networks” and “systems” may be used interchangeably.

[0024] An OFDMA network may implement a radio technology such as evolved UTRA (E-UTRA), Institute of Electrical and Electronic Engineers (IEEE) 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM and the like. UTRA, E-UTRA, and Global System for Mobile Communications (GSM) are part of universal mobile telecommunication system (UMTS). In particular, long term evolution (LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documents provided from an organization named “3^rd Generation Partnership Project” (3GPP), and cdma2000 is described in documents from an organization named “3^rd Generation Partnership Project 2" (3GPP2). These various radio technologies and standards are known or are being developed. For example, the 3^rd Generation Partnership Project (3 GPP) is a collaboration between groups of telecommunications associations that aims to define a globally applicable third generation (3G) mobile phone specification. 3 GPP long term evolution (LTE) is a 3GPP project which was aimed at improving the universal mobile telecommunications system (UMTS) mobile phone standard. The 3 GPP may define specifications for the next generation of mobile networks, mobile systems, and mobile devices. The present disclosure is concerned with the evolution of wireless technologies from LTE, 4G, 5G, NR, and beyond with shared access to wireless spectrum between networks using a collection of new and different radio access technologies or radio air interfaces.

[0025] In particular, 5G networks contemplate diverse deployments, diverse spectrum, and diverse services and devices that may be implemented using an OFDM-based unified, air interface. In order to achieve these goals, further enhancements to LTE and LTE-A are considered in addition to development of the new radio technology for 5G NR networks. The 5G NR will be capable of scaling to provide coverage (1) to a massive Internet of things (loTs) with an ultra-high density (e.g., ~IM nodes/km2), ultra-low complexity (e.g., ~10s of bits/sec), ultra-low energy (e.g., ~10+ years of battery life), and deep coverage with the capability to reach challenging locations; (2) including mission-critical control with strong security to safeguard sensitive personal, financial, or classified information, ultra-high reliability (e.g., -99.9999% reliability), ultra-low latency (e.g., - 1 ms), and users with wide ranges of mobility or lack thereof; and (3) with enhanced mobile broadband including extreme high capacity (e.g., - 10 Tbps/km2), extreme data rates (e.g., multi-Gbps rate, 100+ Mbps user experienced rates), and deep awareness with advanced discovery and optimizations.

[0026] The 5G NR may be implemented to use optimized OFDM-based waveforms with scalable numerology and transmission time interval (TT1); having a common, flexible framework to efficiently multiplex services and features with a dynamic, low- latency time division duplex (TDD)Zfrequency division duplex (FDD) design; and with advanced wireless technologies, such as massive multiple input, multiple output (MIMO), robust millimeter wave (mmWave) transmissions, advanced channel coding, and device-centric mobility. Scalability of the numerology in 5G NR, with scaling of subcarrier spacing, may efficiently address operating diverse services across diverse spectrum and diverse deployments. For example, in various outdoor and macro coverage deployments of less than 3GHz FDD/TDD implementations, subcarrier spacing may occur with 15 kHz, for example over 5, 10, 20 MHz, and the like bandwidth (BW). For other various outdoor and small cell coverage deployments of TDD greater than 3 GHz, subcarrier spacing may occur with 30 kHz over 80/100 MHz BW. For other various indoor wideband implementations, using a TDD over the unlicensed portion of the 5 GHz band, the subcarrier spacing may occur with 60 kHz over a 160 MHz BW. Finally, for various deployments transmitting with mmWave components at a TDD of 28 GHz, subcarrier spacing may occur with 120 kHz over a 500MHz BW.

[0027] The scalable numerology of the 5G NR facilitates scalable TTI for diverse latency and quality of service (QoS) requirements. For example, shorter TTI may be used for low latency and high reliability, while longer TTI may be used for higher spectral efficiency. The efficient multiplexing of long and short TTIs to allow transmissions to start on symbol boundaries. 5G NR also contemplates a self-contained integrated subframe design with uplink/downlink scheduling information, data, and acknowledgement in the same subframe. The self-contained integrated subframe supports communications in unlicensed or contention-based shared spectrum, adaptive uplink/downlink that may be flexibly configured on a per-cell basis to dynamically switch between uplink and downlink to meet the current traffic needs.

[0028] Various other aspects and features of the disclosure are further described below. It should be apparent that the teachings herein may be embodied in a wide variety of forms and that any specific structure, function, or both being disclosed herein is merely representative and not limiting. Based on the teachings herein one of an ordinary level of skill in the art should appreciate that an aspect disclosed herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, such an apparatus may be implemented or such a method may be practiced using other structure, functionality, or structure and functionality in addition to or other than one or more of the aspects set forth herein. For example, a method may be implemented as part of a system, device, apparatus, and/or as instructions stored on a computer readable medium for execution on a processor or computer. Furthermore, an aspect may include at least one element of a claim.

[0029] The deployment of NR over an unlicensed spectrum is referred to as NR- unlicensed (NR-U). Federal Communications Commission (FCC) and European Telecommunications Standards Institute (ETSI) are working on regulating 6 GHz as a new unlicensed band for wireless communications. The addition of 6 GHz bands allows for hundreds of megahertz (MHz) of bandwidth (BW) available for unlicensed band communications. Additionally, NR-U may also be deployed over 2.4 GHz unlicensed bands, which are currently shared by various radio access technologies (RATs), such as IEEE 802.11 wireless local area network (WLAN) or WiFi and/or license assisted access (LAA). Sidelink communications may benefit from utilizing the additional bandwidth available in an unlicensed spectrum. However, channel access in a certain unlicensed spectrum may be regulated by authorities. For instance, some unlicensed bands may impose restrictions on the power spectral density (PSD) and/or minimum occupied channel bandwidth (OCB) for transmissions in the unlicensed bands. For example, the unlicensed national information infrastructure (UNIX) radio band has a minimum OCB requirement of about at least 70 percent (%).

[0030] Some sidelink systems may operate over a 20 MHz bandwidth, e.g., for listen before talk (LBT) based channel accessing, in an unlicensed band. A BS may configure a sidelink resource pool over one or multiple 20 MHz LBT sub-bands for sidelink communications. A sidelink resource pool is typically allocated with multiple frequency subchannels within a sidelink band width part (SL-BWP) and a sidelink UE may select a sidelink resource (e.g., one or multiple subchannel) in frequency and one or multiple slots in time) from the sidelink resource pool for sidelink communication.

[0031] Deployment of communication systems, such as 5G new radio (NR) systems, may be arranged in multiple manners with various components or constituent parts. In a 5G NR system, or network, a network node, a network entity, a mobility element of a network, a radio access network (RAN) node, a core network node, a network element, or a network equipment, such as a base station (BS), or one or more units (or one or more components) performing base station functionality, may be implemented in an aggregated or disaggregated architecture. For example, a BS (such as a Node B (NB), evolved NB (eNB), NR BS, 5G NB, access point (AP), a transmit receive point (TRP), or a cell, etc.) may be implemented as an aggregated base station (also known as a standalone BS or a monolithic BS) or a disaggregated base station.

[0032] An aggregated base station may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. A disaggregated base station may be configured to utilize a protocol stack that is physically or logically distributed among two or more units (such as one or more central or centralized units (CUs), one or more distributed units ( DUs), or one or more radio units ( RUs)). In some aspects, a CU may be implemented within a RAN node, and one or more DUs may be co-located with the CU, or alternatively, may be geographically or virtually distributed throughout one or multiple other RAN nodes. The DUs may be implemented to communicate with one or more RUs. Each of the CU, DU and RU also may be implemented as virtual units, i.e., a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU).

[0033] Base station-type operation or network design may consider aggregation characteristics of base station functionality. For example, disaggregated base stations may be utilized in an integrated access backhaul (IAB) network, an open radio access network (O-RAN (such as the network configuration sponsored by the O-RAN Alliance)), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)). Disaggregation may include distributing functionality across two or more units at various physical locations, as well as distributing functionality for at least one unit virtually, which may enable flexibility in network design. The various units of the disaggregated base station, or disaggregated RAN architecture, may be configured for wired or wireless communication with at least one other unit.

[0034] Various aspects relate generally to wireless communication and more particularly to signaling for dynamic waveform switching. Some aspects more specifically relate to a network unit signaling a user equipment (UE) to switch between a first waveform type and a second waveform type for uplink communications. In some examples, a network unit may transmit an indicator to the UE to enable switching between the waveform types. When waveform switching is enabled, the network unit may transmit DCI to the UE indicating which waveform type to use for uplink communications. In some examples, the size of the DCI may be the same size for the first waveform type and the second waveform type. As such, the UE may blind decode the DCI using a common DCI size for the first waveform type and the second waveform type. The DCI may further include scheduled resources for a physical uplink shared channel (PUSCH) communication associated with the UE. The UE may transmit PUSCH communications to the network unit via the scheduled resources using the indicated waveform type.

[0035] Additionally or alternatively, the UE may switch between the first waveform type and the second waveform type on a semi-static basis. In some examples, a network unit may transmit an indicator to the UE to enable switching between the waveform types. When waveform switching is enabled, the network unit may transmit non-uplink scheduling DCI and/or a MAC-CE communication to the UE indicating which waveform type to use for uplink communications. The network unit may subsequently transmit uplink scheduling DCI to the UE using a DCI size associated with the previously indicated waveform type. The DCI size associated with the first waveform type may be different from the DCI associated with the second waveform type. As such, the UE may blind decode the DCI based on the DCI size associated with the indicated waveform type. The UE may transmit PUSCH communications to the network unit via the scheduled resources using the indicated waveform type.

[0036] Particular aspects of the subject matter described in this disclosure may be implemented to realize one or more of the following potential advantages. In some examples, by implementing dynamic waveform switching according to embodiments of the present disclosure, the described techniques may be used to reduce computing resources, memory requirements, latency, and/or power consumption in the UE by blind decoding a DCI having a common size for the first and second waveform types as compared to blind decoding a first DCI associated with the first waveform type and blind decoding a second, different sized DCI associated with the second waveform type. The dynamic waveform switching according to embodiments of the present disclosure may increase network coverage and/or network capacity. For example, the UE may switch to transmitting uplink communications using a DFT-s-OFDM waveform to increase range and coverage. In some examples, the UE may switch to transmitting uplink communications using a CP-OFDM waveform to increase throughput and/or data rate.

[0037] FIG. 1 illustrates a wireless communication network 100 according to some aspects of the present disclosure. The network 100 includes a number of base stations (BSs) 105 and other network entities. A BS 105 may be a station that communicates with UEs 115 and may also be referred to as an evolved node B (eNB), a next generation eNB (gNB), an access point, and the like. Each BS 105 may provide communication coverage for a particular geographic area. In 3 GPP, the term “cell” may refer to this particular geographic coverage area of a BS 105 and/or a BS subsystem serving the coverage area, depending on the context in which the term is used.

[0038] A BS 105 may provide communication coverage for a macro cell or a small cell, such as a pico cell or a femto cell, and/or other types of cell. A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a pico cell, would generally cover a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a femto cell, would also generally cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, and the like). A BS for a macro cell may be referred to as a macro BS. A BS for a small cell may be referred to as a small cell BS, a pico BS, a femto BS or a home BS. In the example shown in FIG. 1, the BSs 105d and 105e may be regular macro BSs, while the BSs 105a-105c may be macro BSs enabled with one of three dimension (3D), full dimension (FD), or massive M1M0. The BSs 105a- 105c may take advantage of their higher dimension MIMO capabilities to exploit 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. The BS 105f may be a small cell BS which may be a home node or portable access point. A BS 105 may support one or multiple (e.g., two, three, four, and the like) cells.

[0039] The network 100 may support synchronous or asynchronous operation. For synchronous operation, the BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, the BSs may have different frame timing, and transmissions from different BSs may not be aligned in time.

[0040] The UEs 115 are dispersed throughout the wireless network 100, and each UE 115 may be stationary or mobile. A UE 115 may also be referred to as a terminal, a mobile station, a subscriber unit, a station, or the like. A UE 115 may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, or the like. In one aspect, a UE 115 may be a device that includes a Universal Integrated Circuit Card (UICC). In another aspect, a UE may be a device that does not include a UICC. In some aspects, the UEs 115 that do not include UICCs may also be referred to as loT devices or internet of everything (loE) devices. The UEs 115a-l 15d are examples of mobile smart phone-type devices accessing network 100. A UE 115 may also be a machine specifically configured for connected communication, including machine type communication (MTC), enhanced MTC (eMTC), narrowband loT (NB-IoT) and the like. The UEs 115e- 115h are examples of various machines configured for communication that access the network 100. The UEs 115i-l 15k are examples of vehicles equipped with wireless communication devices configured for communication that access the network 100. A UE 115 may be able to communicate with any type of the BSs, whether macro BS, small cell, or the like. In FIG. 1, a lightning bolt (e.g., communication links) indicates wireless transmissions between a UE 115 and a serving BS 105, which is a BS designated to serve the UE 115 on the downlink (DL) and/or uplink (UL), desired transmission between BSs 105, backhaul transmissions between BSs, or sidelink transmissions between UEs 115.

[0041] In operation, the BSs 105a-105c may serve the UEs 115a and 115b using 3D beamforming and coordinated spatial techniques, such as coordinated multipoint (CoMP) or multi-connectivity. The macro BS 105d may perform backhaul communications with the BSs 105a- 105c, as well as small cell, the BS 105f. The macro BS 105d may also transmits multicast services which are subscribed to and received by the UEs 115c and 115d. Such multicast services may include mobile television or stream video, or may include other services for providing community information, such as weather emergencies or alerts, such as Amber alerts or gray alerts.

[0042] The BSs 105 may also communicate with a core network. The core network may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. At least some of the BSs 105 (e.g., which may be an example of an evolved NodeB (eNB) or an access node controller (ANC)) may interface with the core network 130 through backhaul links (e.g., SI, S2, etc.) and may perform radio configuration and scheduling for communication with the UEs 115. In various examples, the BSs 105 may communicate, either directly or indirectly (e.g., through core network), with each other over backhaul links (e.g., XI, X2, etc.), which may be wired or wireless communication links.

[0043] The network 100 may also support mission critical communications with ultrareliable and redundant links for mission critical devices, such as the UE 115e, which may be a vehicle (e.g., a car, a truck, a bus, an autonomous vehicle, an aircraft, a boat, etc.). Redundant communication links with the UE 115e may include links from the macro BSs 105d and 105e, as well as links from the small cell BS 105f. Other machine type devices, such as the UE 115f (e.g., a thermometer), the UE 115g (e.g., smart meter), and UE 115h (e.g., wearable device) may communicate through the network 100 either directly with BSs, such as the small cell BS 105f, and the macro BS 105e, or in multi-hop configurations by communicating with another user device which relays its information to the network, such as the UE 115f communicating temperature measurement information to the smart meter, the UE 115g, which is then reported to the network through the small cell BS 105f. In some aspects, the UE 115h may harvest energy from an ambient environment associated with the UE 115h. The network 100 may also provide additional network efficiency through dynamic, low-latency TDD/FDD communications, such as vehicle-to-vehicle (V2V), vehicle-to-everything (V2X), cellular- vehicle-to-everything (C-V2X) communications between a UE 115i, 115j , or 115k and other UEs 115, and/or vehicle-to-infrastructure (V2I) communications between a UE 115i, 115j, or 115k and a BS 105. [0044] In some implementations, the network 100 utilizes OFDM-based waveforms for communications. An OFDM-based system may partition the system BW into multiple (K) orthogonal subcarriers, which are also commonly referred to as subcarriers, tones, bins, or the like. Each subcarrier may be modulated with data. In some instances, the subcarrier spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system BW. The system BW may also be partitioned into subbands. In other instances, the subcarrier spacing and/or the duration of TTIs may be scalable.

[0045] In some instances, the BSs 105 may assign or schedule transmission resources (e.g., in the form of time-frequency resource blocks (RB)) for downlink (DL) and uplink (UL) transmissions in the network 100. DL refers to the transmission direction from a BS 105 to a UE 115, whereas UL refers to the transmission direction from a UE 115 to a BS 105. The communication may be in the form of radio frames. A radio frame may be divided into a plurality of subframes, for example, about 10. Each subframe may be divided into slots, for example, about 2. Each slot may be further divided into minislots. In a FDD mode, simultaneous UL and DL transmissions may occur in different frequency bands. For example, each subframe includes a UL subframe in a UL frequency band and a DL subframe in a DL frequency band. In a TDD mode, UL and DL transmissions occur at different time periods using the same frequency band. For example, a subset of the subframes (e.g., DL subframes) in a radio frame may be used for DL transmissions and another subset of the subframes (e.g., UL subframes) in the radio frame may be used for UL transmissions.

[0046] The DL subframes and the UL subframes may be further divided into several regions. For example, each DL or UL subframe may have pre-defined regions for transmissions of reference signals, control information, and data. Reference signals are predetermined signals that facilitate the communications between the BSs 105 and the UEs 115. For example, a reference signal may have a particular pilot pattern or structure, where pilot tones may span across an operational BW or frequency band, each positioned at a pre-defined time and a pre-defined frequency. For example, a BS 105 may transmit cell specific reference signals (CRSs) and/or channel state information - reference signals (CSI-RSs) to enable a UE 115 to estimate a DL channel. Similarly, a UE 115 may transmit sounding reference signals (SRSs) to enable a BS 105 to estimate a UL channel. Control information may include resource assignments and protocol controls. Data may include protocol data and/or operational data. In some instances, the BSs 105 and the UEs 115 may communicate using self-contained subframes. A self- contained subframe may include a portion for DL communication and a portion for UL communication. A self-contained subframe may be DL-centric or UL-centric. A DL- centric subframe may include a longer duration for DL communication than for UL communication. A UL-centric subframe may include a longer duration for UL communication than for UL communication.

[0047] In some instances, the network 100 may be an NR network deployed over a licensed spectrum. The BSs 105 may transmit synchronization signals (e.g., including a primary synchronization signal (PSS) and a secondary synchronization signal (SSS)) in the network 100 to facilitate synchronization. The BSs 105 may broadcast system information associated with the network 100 (e.g., including a master information block (MIB), remaining minimum system information (RMSI), and other system information (OSI)) to facilitate initial network access. In some instances, the BSs 105 may broadcast the PSS, the SSS, and/or the MIB in the form of synchronization signal blocks (SSBs) over a physical broadcast channel (PBCH) and may broadcast the RMSI and/or the OSI over a physical downlink shared channel (PDSCH).

[0048] In some instances, a UE 115 attempting to access the network 100 may perform an initial cell search by detecting a PSS from a BS 105. The PSS may enable synchronization of period timing and may indicate a physical layer identity value. The UE 115 may then receive an SSS. The SSS may enable radio frame synchronization, and may provide a cell identity value, which may be combined with the physical layer identity value to identify the cell. The SSS may also enable detection of a duplexing mode and a cyclic prefix length. The PSS and the SSS may be located in a central portion of a carrier or any suitable frequencies within the carrier.

[0049] After receiving the PSS and SSS, the UE 115 may receive a MIB. The MIB may include system information for initial network access and scheduling information for RMSI and/or OSL After decoding the MIB, the UE 115 may receive RMSI and/or OSI. The RMSI and/or OSI may include radio resource control (RRC) information related to random access channel (RACH) procedures, paging, control resource set (CORESET) for physical downlink control channel (PDCCH) monitoring, physical uplink control channel (PUCCH), physical uplink shared channel (PUSCH), power control, SRS, and cell barring.

[0050] After obtaining the MIB, the RMSI and/or the OSI, the UE 115 may perform a random access procedure to establish a connection with the BS 105. For the random access procedure, the UE 115 may transmit a random access preamble and the BS 105 may respond with a random access response. Upon receiving the random access response, the UE 115 may transmit a connection request to the BS 105 and the BS 105 may respond with a connection response (e.g., contention resolution message).

[0051] After establishing a connection, the UE 115 and the BS 105 may enter a normal operation stage, where operational data may be exchanged. For example, the BS 105 may schedule the UE 115 for UL and/or DL communications. The BS 105 may transmit UL and/or DL scheduling grants to the UE 115 via a PDCCH. The BS 105 may transmit a DL communication signal to the UE 115 via a PDSCH according to a DL scheduling grant. The UE 115 may transmit a UL communication signal to the BS 105 via a PUSCH and/or PUCCH according to a UL scheduling grant.

[0052] The network 100 may be designed to enable a wide range of use cases. While in some examples a network 100 may utilize monolithic base stations, there are a number of other architectures which may be used to perform aspects of the present disclosure. For example, a BS 105 may be separated into a remote radio head (RRH) and baseband unit (BBU). BBUs may be centralized into a BBU pool and connected to RRHs through low-latency and high-bandwidth transport links, such as optical transport links. BBU pools may be cloud-based resources. In some aspects, baseband processing is performed on virtualized servers running in data centers rather than being co-located with a BS 105. In another example, based station functionality may be split between a remote unit (RU), distributed unit (DU), and a central unit (CU). An RU generally performs low physical layer functions while a DU performs higher layer functions, which may include higher physical layer functions. A CU performs the higher RAN functions, such as radio resource control (RRC).

[0053] For simplicity of discussion, the present disclosure refers to methods of the present disclosure being performed by base stations, or more generally network entities, while the functionality may be performed by a variety of architectures other than a monolithic base station. In addition to disaggregated base stations, aspects of the present disclosure may also be performed by a centralized unit (CU), a distributed unit (DU), a radio unit (RU), a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC), a NonReal Time (Non-RT) RIC, integrated access and backhaul (IAB) node, a relay node, a sidelink node, etc.

[0054] In some aspects, the UE 115 may receive an indicator from the BS 105 indicating dynamic waveform switching between a first waveform type and a second waveform type. The UE 115 may monitor, based on the indicator, for downlink control information (DCI) from the network unit, wherein at least one of a size of the DCI, a size of a bitfield of the DCI, or a location of the bitfield of the DCI is interpreted based on the indicator.

[0055] In some aspects, a first UE 115 may select first resources from a resource pool and select second resources from the resource pool. The first UE 115 may jointly map the first resources and the second resources to a same size of nominal resources. The first UE 115 may transmit, to a second UE 115 using the first resources, a first sidelink communication including a transport block (TB) and an indicator indicating the second resources. The first UE 115 may transmit, to the second sidelink UE using the second resources, a second sidelink communication including the TB. In some aspect, a size of the TB may be based on at least the size of the nominal resources.

[0056] FIG. 2 shows a diagram illustrating an example disaggregated base station 200 architecture. The disaggregated base station 200 architecture may include one or more central units ( CUs) 210 that may communicate directly with a core network 220 via a backhaul link, or indirectly with the core network 220 through one or more disaggregated base station units (such as a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC) 225 via an E2 link, or a Non- Real Time (Non-RT) RIC 215 associated with a Service Management and Orchestration (SMO) Framework 205, or both). A CU 210 may communicate with one or more distributed units ( DUs) 230 via respective midhaul links, such as an Fl interface. The DUs 230 may communicate with one or more radio units ( RUs) 240 via respective fronthaul links. The RUs 240 may communicate with respective UEs 115 via one or more radio frequency (RF) access links. In some implementations, the UE 115 may be simultaneously served by multiple RUs 240.

[0057] Each of the units, i.e., the CUs 210, the DUs 230, the RUs 240, as well as the Near-RT RICs 225, the Non-RT RICs 215 and the SMO Framework 205, may include one or more interfaces or be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units, or an associated processor or controller providing instructions to the communication interfaces of the units, may be configured to communicate with one or more of the other units via the transmission medium. For example, the units may include a wired interface configured to receive or transmit signals over a wired transmission medium to one or more of the other units. Additionally, the units may include a wireless interface, which may include a receiver, a transmitter or transceiver (such as a radio frequency (RF) transceiver), configured to receive or transmit signals, or both, over a wireless transmission medium to one or more of the other units.

[0058] In some aspects, the CU 210 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), or the like. Each control function may be implemented with an interface configured to communicate signals with other control functions hosted by the CU 210. The CU 210 may be configured to handle user plane functionality (i.e. , Central Unit - User Plane (CU-UP)), control plane functionality (i.e., Central Unit - Control Plane (CU-CP)), or a combination thereof. In some implementations, the CU 210 may be logically split into one or more CU-UP units and one or more CU-CP units. The CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface, such as the El interface when implemented in an O-RAN configuration. The CU 210 may be implemented to communicate with the DU 230, as necessary, for network control and signaling.

[0059] The DU 230 may correspond to a logical unit that includes one or more base station functions to control the operation of one or more RUs 240. In some aspects, the DU 230 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, or the like) depending, at least in part, on a functional split, such as those defined by the 3^rd Generation Partnership Project (3GPP). In some aspects, the DU 230 may further host one or more low PHY layers. Each layer (or module) may be implemented with an interface configured to communicate signals with other layers (and modules) hosted by the DU 230, or with the control functions hosted by the CU 210. [0060] Lower-layer functionality may be implemented by one or more RUs 240. In some deployments, an RU 240, controlled by a DU 230, may correspond to a logical node that hosts RF processing functions, or low-PHY layer functions (such as performing fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, or the like), or both, based at least in part on the functional split, such as a lower layer functional split. In such an architecture, the RU(s) 240 may be implemented to handle over the air (OTA) communication with one or more UEs 115. In some implementations, real-time and non-real-time aspects of control and user plane communication with the RU(s) 240 may be controlled by the corresponding DU 230. In some scenarios, this configuration may enable the DU(s) 230 and the CU 210 to be implemented in a cloud-based RAN architecture, such as a vRAN architecture.

[0061] The SMO Framework 205 may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non- virtualized network elements, the SMO Framework 205 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements which may be managed via an operations and maintenance interface (such as an 01 interface). For virtualized network elements, the SMO Framework 205 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 290) to perform network element life cycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an 02 interface). Such virtualized network elements may include CUs 210, DUs 230, RUs 240 and Near-RT RICs 225. In some implementations, the SMO Framework 205 may communicate with a hardware aspect of a 4G RAN, such as an open eNB (O-eNB) 211, via an 01 interface. Additionally, in some implementations, the SMO Framework 205 may communicate directly with one or more RUs 240 via an 01 interface. The SMO Framework 205 also may include a Non-RT RIC 215 configured to support functionality of the SMO Framework 205.

[0062] The Non-RT RIC 215 may be configured to include a logical function that enables non-real-time control and optimization of RAN elements and resources, Artificial Intelligence/Machine Learning (AI/ML) workflows including model training and updates, or policy-based guidance of applications/features in the Near-RT RIC 225. The Non-RT RIC 215 may be coupled to or communicate with (such as via an Al interface) the Near-RT RIC 225. The Near-RT RIC 225 may be configured to include a logical function that enables near-real-time control and optimization of RAN elements and resources via data collection and actions over an interface (such as via an E2 interface) connecting one or more CUs 210, one or more DUs 230, or both, as well as an O-eNB, with the Near-RT RIC 225.

[0063] In some implementations, to generate AI/ML models to be deployed in the Near- RT RIC 225, the Non-RT RIC 215 may receive parameters or external enrichment information from external servers. Such information may be utilized by the Near-RT RIC 225 and may be received at the SMO Framework 205 or the Non-RT R1C 215 from non-network data sources or from network functions. In some examples, the Non-RT RIC 215 or the Near-RT RIC 225 may be configured to tune RAN behavior or performance. For example, the Non-RT RIC 215 may monitor long-term trends and patterns for performance and employ AFML models to perform corrective actions through the SMO Framework 205 (such as reconfiguration via 01) or via creation of RAN management policies (such as Al policies).

[0064] In some aspects, the UE 115 may receive an indicator from the RU 240 indicating dynamic waveform switching between a first waveform type and a second waveform type. The UE 115 may monitor, based on the indicator, for downlink control information (DCI) from the RU 240, wherein at least one of a size of the DCI, a size of a bitfield of the DCI, or a location of the bitfield of the DCI is interpreted based on the indicator.

[0065] In some aspects, a first UE 115 may select first resources from a resource pool and select second resources from the resource pool. The first UE 115 may jointly map the first resources and the second resources to a same size of nominal resources. The first UE 115 may transmit, to a second UE 115 using the first resources, a first sidelink communication including a transport block (TB) and an indicator indicating the second resources. The first UE 115 may transmit, to the second sidelink UE using the second resources, a second sidelink communication including the TB. In some aspect, a size of the TB may be based on at least the size of the nominal resources.

[0066] FIG. 3 illustrates a frequency interlace 314 across multiple resource block sets 310 according to some aspects of the present disclosure. As shown by reference number 308, a carrier bandwidth may be divided into a number of RB sets 310. In the depicted example, the carrier bandwidth may be an unlicensed carrier that includes two RB sets 310a and 310b, but in other cases, the carrier bandwidth 308 may include more or fewer RB sets 310. For example, in some cases, the carrier bandwidth 308 may be 40 MHz, and may include two 20 MHz RB sets 310a and 310b. In some other cases, the carrier bandwidth 308 may be 100 MHz, and may include five 20 MHz RB sets 310.

[0067] The number of RBs within each RB set 310 and the number of RBs in frequency interlace 314 may vary according to certain configurations such as a guard band 312 configuration. More particularly, depending on the guard band 312 configuration, each RB set may include nine, ten, or eleven RBs associated with frequency interlace 314. When frequency interlace 314 is across two contiguous RB sets 310a and 310b, the frequency interlace 314 may also be across the guard band 312. In the example of FIG. 3, the frequency interlace 314 includes 24 RBs across RB set 310a, guard band 312, and RB set 310b.

[0068] FIG. 4 illustrates frequency interlaces 314a and 314b across RB set 310a according to some aspects of the present disclosure. As shown by reference number 308, a carrier bandwidth may be divided into a number of RB sets 310. In the depicted example, the carrier bandwidth may be an unlicensed carrier that includes two RB sets 310a and 310b, but in other cases, the carrier bandwidth 308 may include more or fewer RB sets 310. For example, in some cases, the carrier bandwidth 308 may be 40 MHz, and may include two 20 MHz RB sets 310a and 310b. In some other cases, the carrier bandwidth 308 may be 100 MHz, and may include five 20 MHz RB sets 310.

[0069] In the example of FIG. 4 two frequency interlaces 314a and 314b are across a single RB set 310a. In this case, the frequency interlaces 314a and 314b do not extend over the guard band 312 as shown in the example of FIG. 3 and therefore the frequency interlaces 314a and 314b have fewer RBs. In some aspects, a UE may select the frequency interlace 314 of FIG. 3 having 24 RBs for an initial sidelink transmission of a TB. The UE may then select the two frequency interlaces 314a and 314b across a single RB set 310a having 22 RBs for a retransmission of the TB. In this example, a resource size inconsistency exists between the resources for the initial transmission and the resources for the retransmission. In some aspects, the resource size inconsistency may result from the random resource selection process associated with sidelink mode 2 and/or the LBT uncertainty when operating in an unlicensed band. Aspects of the present disclosure may mitigate issues associated with resource size inconsistency by determining a nominal resource size and corresponding TB size.

[0070] FIG. 5 is a flow diagram of a communication method 500 according to some aspects of the present disclosure. Aspects of the method 500 may be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device or other suitable means for performing the actions. For example, a wireless communication device, such as the UE 115 or the UE 600 may utilize one or more components, such as the processor 602, the memory 604, the variable subchannel module 608, the transceiver 610, the modem 612, and the one or more antennas 616, to execute aspects of method 500. The method 500 may employ similar mechanisms as in the networks 100 and 200 and the aspects and actions described with respect to FIGS. 3-4. As illustrated, the method 500 includes a number of enumerated actions, but the method 500 may include additional actions before, after, and in between the enumerated actions. In some aspects, one or more of the enumerated actions may be omitted or performed in a different order.

[0071] At action 502, the UE 115a may select first resources from a resource pool. In this regard, the UE 115a may select first resources for transmitting a transport block (TB) in a first physical sidelink shared channel (PSSCH). The first resources may include time resources. For example, the time resources may include slot(s), symbol(s), frame(s), subframe(s), time period(s) (e.g., a number of milliseconds), or other suitable time resources. In some aspects, the first resources may include frequency resources. For example, the frequency resources may include subchannel(s), frequency bands, resource block set(s), frequency interlace(s), bandwidth part(s), or other suitable frequency resources.

[0072] At action 503, the UE 115a may select second resources from the resource pool. In this regard, the UE 115a may select second resources for transmitting (e.g., retransmitting) the TB in a second PSSCH. The second resources may include time resources. For example, the time resources may include slot(s), symbol(s), frame(s), subframe(s), time period(s) (e.g., a number of milliseconds), or other suitable time resources. In some aspects, the second resources may include frequency resources. For example, the frequency resources may include subchannel(s), frequency bands, resource block set(s), frequency interlace(s), bandwidth part(s), or other suitable frequency resources. In some aspect, the first sidelink UE may select the first and second resources from the resource pool at the same time.

[0073] At action 504, the UE 115a may jointly map the first resources and the second resources to a same size of nominal resources. For example, the UE 115a may store a lookup table (e.g., store in memory 604) that maps the first resources and the second resources to a nominal resource size (e.g., a single resource size). Additionally or alternatively, the UE 115a and the UE 115b may use a pre-defined/pre-configured formula, that takes the resources (sizes) as input and outputs the nominal size. In some aspects, the size of the nominal resources may be equal to the smaller of the size of the first resources or the size of the second resources. The size of the nominal resources may be selected such that the size of the first resources and the second resources are the same. For example, the first resources may include 5 resource blocks (RBs) while the second resources may include 8 RBs. In this case, the nominal resources may be 5 RBs corresponding to the smaller of the first and second resources. In some aspects, the UE 115b (e.g., the sidelink receiving UE) may also store the lookup table (e.g., the same lookup table as stored in the sidelink transmitting UE 115a). The UE 115b may receive an indication of the first resources and the second resources and jointly map the first resources and the second resources to a same size of nominal resources. The UE 115b may similarly determine the TB size based on the nominal resources indicated by the lookup table.

[0074] In some aspects, the lookup table may indicate a TB size that maps (e.g., corresponds) to the size of the nominal resources. In some aspects, the lookup table may be preconfigured in the UE 115a and/or UE 115b. Additionally or alternatively, the UE 115a and/or UE 115b may receive the lookup table from a network unit (e.g., the network unit 700, the BS 105, the RU 240, the DU 230, and/or the CU 210). In some aspects, the mapping of the TB size to the nominal resources may be based on the number of resource block (RB) sets in the nominal resources, the number of subchannels in the nominal resources, and/or the number of frequency interlaces in the nominal resources. The UE 115b may use the same TB size for decoding both an initial transmission from the UE 115a and a retransmission of the TB from the UE 115a (e.g., a second transmission of the TB, a third transmission of the TB, etc.). In some aspects, the UE 115a may decide whether to use a nominal resource size for determining the TB size of the transmissions. When the UE 115a decides to use the lookup table procedure, the UE 115a may transmit an indicator to the UE 115b indicating that the UE 115a and UE 115b should use the lookup table procedure. In this regard, the UE 115a may transmit the indicator in SCI (e.g., SCI-1 and/or SCI-2). In some aspects, the indicator may include a single bit field to indicate whether the UE 115a and UE 115b should use the lookup table procedure. However, if the UE 115b fails to receive the first sidelink communication (e.g., the initial TB transmission) including the indicator in the SCI, the UE 115b may be unable to determine the TB size. Additionally or alternatively, the UE 115a may transmit an indicator to the UE 115b indicating the TB size. In this regard, the UE 115a may transmit the TB size indicator in SCI (e.g., SCI-1 and/or SCI-2). The UE 115a may transmit the TB size indicator in the first transmission of the TB and in all retransmissions of the TB. The indicator may explicitly indicate the TB size (e.g., the absolute TB size). Additionally or alternatively, the indicator may indicate the TB size as an offset from a reference TB size (e.g., a preconfigured/default TB size). The size of the TB may be based on the offset from the reference TB size. For example, the UE 115b may determine the TB size by adding or subtracting the offset from the reference TB size.

[0075] Additionally or alternatively, the UE 115a may transmit a PSFCH overhead indicator to the UE 115b indicating a resource size inconsistency due to the second resources including PSFCH resources. In some aspects, the PSFCH overhead indicator may include a single bit field to indicate a resource size inconsistency due to the second resources including PSFCH resources. In this regard, the UE 115a may transmit the PSFCH overhead indicator in SCI (e.g., SCI-1 and/or SCI- 2). The PSFCH overhead indicator may be transmitted in addition to the indicator indicating that the first and UE 115bs should use the lookup table procedure. Transmitting both indicators may allow for PSFCH induced resource inconsistencies and non-PSFCH induced resource inconsistencies to be treated independently. The non-PSFCH induced resource inconsistencies may include resource inconsistencies due to operation in unlicensed frequencies, frequency interlaces having different sizes, frequency interlaces over guard bands, and/or LBT uncertainty. The PSFCH induced resource inconsistencies may be due to the second resources including PSFCH resources.

[0076] Additionally or alternatively, the UE 115a may transmit an implicit indicator to the UE 115b indicating a resource size inconsistency. For example, the implicit indicator may include a physical sidelink control channel (PSCCH) scrambling sequence, a demodulation reference signal (DMRS) sequence, a resource element pattern, and/or other suitable implicit indicator.

[0077] In some aspects, the UE 115a (e.g., the sidelink transmitting UE) may select the first resources from the resource pool and then select the second resources from the resource pool to be the same size as the first resources. The UE 115a may select the first resources by excluding resources from the resource pool whose size is not sufficient to support transmitting the TB. The UE 115a may select the first and second resources from the resources remaining after excluding the resources that are not sufficient to support transmitting the TB. The UE 115a may then select first and second resources from the remaining resources that have the same size. For example, the TB may require two frequency interlaces over one RB set or over two RB sets. The UE 115a may exclude resources over one RB set and select first and second resources that include two frequency interlaces over two RB sets. Alternatively, the UE 115a may exclude resources over two RB sets and select (e.g., randomly select) first and second resources that include two frequency interlaces over one RB set. [0078] Additionally or alternatively, the UE 115a (e.g., the sidelink transmitting UE) may select the first resources from the resource pool using a multi-step procedure. The UE 115a may initially randomly select first resources that are sufficient to support transmitting the TB. The UE 115a may then select the second resources by excluding resources from the resource pool that do not match the size of the first resources. The UE 115a may then randomly select the second resources from the remaining resources in the resource pool. The UE 115a may repeat this process to select resources for additional retransmissions of the TB. In some aspects, if there are not enough remaining resources in the resource pool that match the size of the first resources, the UE 115a may restrict the number of retransmissions based on the amount of remaining resources that match the size of the first resource. Additionally or alternatively, the UE 115a may repeat the multi-step selection process by excluding the initially selected first resources. Additionally or alternatively, the UE 115a may repeat the process by introducing resources into the resource pool that have been previously excluded by other UE’s resource reservations.

[0079] At action 506, the UE 115a may transmit a first sidelink communication including the TB to the UE 115b. In this regard, the UE 115a may transmit a first PSSCH communication using the first resources. The first sidelink communication may include the indicator indicating the second resources and/or an indicator indicating the size of the TB. The indicator(s) may be included in SCI-1 and/or SCI-2. The first sidelink communication including the TB may be an initial transmission of the TB. [0080] At action 507, the UE 115b may jointly map the first resources and the second resources to a same size of nominal resources. The first sidelink communication may indicate the first resources and the second resources but not the mapping of the first resources and second resources to the nominal resources. The UE 115a and the UE 115b may each independently perform the mapping of the first resources and second resources to the nominal resources. The joint mapping may include taking both the first resources and the second resources into account when mapping to the nominal resources. For example, the lookup table may jointly map the first resources and the second resources by having each row of the lookup table include a size of the first resources, a size of the second resources, and a size of the nominal resources corresponding to the first and second resources. The UE 115b may store a lookup table (e.g., store in memory 604) that maps the first resources and the second resources to a nominal resource size (e.g., a single resource size). In some aspects, the UE 115b (e.g., the sidelink receiving UE) may store the same lookup table as stored in the sidelink transmitting UE 115a. The UE 115b may receive an indication of the first resources and the second resources and jointly map the first resources and the second resources to a same size of nominal resources. The UE 115b may similarly determine the TB size based on the nominal resources indicated by the lookup table.

[0081] At action 508, the first sidelink communication may not be correctly decoded by the UE 115b. The UE 115b may transmit a NACK to the UE 115a indicating the first sidelink communication was not correctly decoded. In response, the UE 115a may retransmit the TB in the second sidelink communication.

[0082] At action 510, the UE 115a may transmit a second sidelink communication including the TB to the UE 115b. In this regard, the UE 115a may transmit a second PSSCH communication using the second resources. The second sidelink communication may include the indicator indicating the second resources and/or an indicator indicating the size of the TB. The indicator(s) may be included in SC1-1 and/or SC1-2. The second sidelink communication including the TB may be a retransmission of the TB. In some aspects, the second sidelink communication may not be correctly decoded by the UE 115b. The UE 115b may transmit a NACK to the UE 115a indicating the second sidelink communication was not correctly decoded. In response, the UE 115a may retransmit the TB in a third sidelink communication. In some aspects, the UE 115b may combine the first transmission of the TB and the retransmission(s) of the TB in order to increase the probability of correctly decoding the TB. The UE 115b may combine the initial transmission and the retransmission(s) based on the same TB size for all transmissions.

[0083] In some aspects, the UE 115a and UE 115b may operate in an unlicensed frequency band. UE 115a may perform a listen-before-talk (LBT) procedure prior to transmitting in the unlicensed band. In some aspects, the UE 115a may perform a successful LBT procedure before transmitting the first sidelink communication in the first resources. However, if the UE 115a performs an unsuccessful LBT prior to the second sidelink communication, the second resources may longer be available and the UE 115a may reselect the second resources. In some aspects, the reselected resources may not be the same size as the originally selected second resources. In this case, the UE 115a may reselect second resources by excluding resources of a size that will result in an invalid code rate (e.g., a code rate less than 120). [0084] FIG. 6 is a block diagram of an exemplary UE 600 according to some aspects of the present disclosure. The UE 600 may be the UE 115 in the network 100, or 200 as discussed above. As shown, the UE 600 may include a processor 602, a memory 604, a variable subchannel module 608, a transceiver 610 including a modem subsystem 612 and a radio frequency (RF) unit 614, and one or more antennas 616. These elements may be coupled with each other and in direct or indirect communication with each other, for example via one or more buses.

[0085] The processor 602 may include a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 602 may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. [0086] The memory 604 may include a cache memory (e.g., a cache memory of the processor 602), random access memory (RAM), magnetoresistive RAM (MRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory, solid state memory device, hard disk drives, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some instances, the memory 604 includes a non-transitory computer- readable medium. The memory 604 may store instructions 606. The instructions 606 may include instructions that, when executed by the processor 602, cause the processor 602 to perform the operations described herein with reference to the UEs 115 in connection with aspects of the present disclosure, for example, aspects of FIGS. 3-6. Instructions 606 may also be referred to as code. The terms “instructions” and “code” should be interpreted broadly to include any type of computer-readable statement(s). For example, the terms “instructions” and “code” may refer to one or more programs, routines, sub-routines, functions, procedures, etc. “Instructions” and “code” may include a single computer-readable statement or many computer-readable statements.

[0087] The variable subchannel module 608 may be implemented via hardware, software, or combinations thereof. For example, the variable subchannel module 608 may be implemented as a processor, circuit, and/or instructions 606 stored in the memory 604 and executed by the processor 602. In some aspects, the variable subchannel module 608 may implement the aspects of FIGS. 3-5. For example, the variable subchannel module 608 may select first resources from a resource pool; select second resources from the resource pool; jointly map the first resources and the second resources to a same size of nominal resources; transmit, to a second sidelink UE using the first resources, a first sidelink communication including a transport block (TB) and an indicator indicating the second resources; and transmit, to the second sidelink UE using the second resources, a second sidelink communication including the TB, wherein a size of the TB is based on at least the size of the nominal resources.

[0088] As shown, the transceiver 610 may include the modem subsystem 612 and the RF unit 614. The transceiver 610 may be configured to communicate bi-directionally with other devices, such as the BSs 105 and/or the UEs 115. The modem subsystem 612 may be configured to modulate and/or encode the data from the memory 604 and the according to a modulation and coding scheme (MCS), e.g., a low-density parity check (LDPC) coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. The RF unit 614 may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.) modulated/encoded data from the modem subsystem 612 (on outbound transmissions) or of transmissions originating from another source such as a UE 115 or a BS 105. The RF unit 614 may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver 610, the modem subsystem 612 and the RF unit 614 may be separate devices that are coupled together to enable the UE 600 to communicate with other devices.

[0089] The RF unit 614 may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information), to the antennas 616 for transmission to one or more other devices. The antennas 616 may further receive data messages transmitted from other devices. The antennas 616 may provide the received data messages for processing and/or demodulation at the transceiver 610. The antennas 616 may include multiple antennas of similar or different designs in order to sustain multiple transmission links. The RF unit 614 may configure the antennas 616.

[0090] In some instances, the UE 600 may include multiple transceivers 610 implementing different RATs (e.g., NR and LTE). In some instances, the UE 600 may include a single transceiver 610 implementing multiple RATs (e.g., NR and LTE). In some instances, the transceiver 610 may include various components, where different combinations of components may implement RATs.

[0091] FIG. 7 is a block diagram of an exemplary network unit 700 according to some aspects of the present disclosure. The network unit 700 may be the BS 105, the CU 210, the DU 230, or the RU 240, as discussed above. As shown, the network unit 700 may include a processor 702, a memory 704, a variable subchannel module 708, a transceiver 710 including a modem subsystem 712 and a RF unit 714, and one or more antennas 716. These elements may be coupled with each other and in direct or indirect communication with each other, for example via one or more buses.

[0092] The processor 702 may have various features as a specific-type processor. For example, these may include a CPU, a DSP, an ASIC, a controller, a FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 702 may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0093] The memory 704 may include a cache memory (e.g., a cache memory of the processor 702), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, a solid state memory device, one or more hard disk drives, memristor-based arrays, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some instances, the memory 704 may include a non-transitory computer- readable medium. The memory 704 may store instructions 706. The instructions 706 may include instructions that, when executed by the processor 702, cause the processor 702 to perform operations described herein, for example, aspects of FIGS. 3-5. Instructions 706 may also be referred to as code, which may be interpreted broadly to include any type of computer-readable statement(s).

[0094] The variable subchannel module 708 may be implemented via hardware, software, or combinations thereof. For example, the variable subchannel module 708 may be implemented as a processor, circuit, and/or instructions 706 stored in the memory 704 and executed by the processor 702.

[0095] In some aspects, the variable subchannel module 708 may implement the aspects of FIGS. 3-5. For example, the variable subchannel module 708 may select first resources from a resource pool; select second resources from the resource pool; jointly map the first resources and the second resources to a same size of nominal resources; transmit, to a second sidelink UE using the first resources, a first sidelink communication including a transport block (TB) and an indicator indicating the second resources; and transmit, to the second sidelink UE using the second resources, a second sidelink communication including the TB, wherein a size of the TB is based on at least the size of the nominal resources.

[0096] Additionally or alternatively, the variable subchannel module 708 may be implemented in any combination of hardware and software, and may, in some implementations, involve, for example, processor 702, memory 704, instructions 706, transceiver 710, and/or modem 712.

[0097] As shown, the transceiver 710 may include the modem subsystem 712 and the RF unit 714. The transceiver 710 may be configured to communicate bi-directionally with other devices, such as the UEs 115 and/or UE 600. The modem subsystem 712 may be configured to modulate and/or encode data according to a MCS, e.g., a LDPC coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. The RF unit 714 may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.) modulated/encoded data from the modem subsystem 712 (on outbound transmissions) or of transmissions originating from another source such as a UE 115 or UE 600. The RF unit 714 may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver 710, the modem subsystem 712 and/or the RF unit 714 may be separate devices that are coupled together at the network unit 700 to enable the network unit 700 to communicate with other devices.

[0098] The RF unit 714 may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information), to the antennas 716 for transmission to one or more other devices. This may include, for example, a configuration indicating a plurality of subslots within a slot according to aspects of the present disclosure. The antennas 716 may further receive data messages transmitted from other devices and provide the received data messages for processing and/or demodulation at the transceiver 710. The antennas 716 may include multiple antennas of similar or different designs in order to sustain multiple transmission links.

[0099] In some instances, the network unit 700 may include multiple transceivers 710 implementing different RATs (e.g., NR and LTE). In some instances, the network unit 700 may include a single transceiver 710 implementing multiple RATs (e.g., NR and LTE). In some instances, the transceiver 710 may include various components, where different combinations of components may implement RATs.

[0100] FIG. 8 is a flow diagram of a communication method 800 according to some aspects of the present disclosure. Aspects of the method 800 can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device or other suitable means for performing the actions. For example, a wireless communication device, such as the UE 115 or the UE 600, may utilize one or more components, such as the processor 602, the memory 604, the variable subchannel module 608, the transceiver 610, the modem 612, and the one or more antennas 616, to execute aspects of method 800. The method 800 may employ similar mechanisms as in the networks 100 and 200 and the aspects and actions described with respect to FIGS. 3-5. As illustrated, the method 800 includes a number of enumerated actions, but the method 800 may include additional actions before, after, and in between the enumerated actions. In some aspects, one or more of the enumerated actions may be omitted or performed in a different order.

[0101] At action 810, the method 800 includes a first sidelink UE (e.g., the UE 115 or the UE 600) selecting first resources from a resource pool. In this regard, the first sidelink UE may select first resources for transmitting a transport block (TB) in a first physical sidelink shared channel (PSSCH). The first resources may include time resources. For example, the time resources may include slot(s), symbol(s), frame(s), subframe(s), time period(s) (e.g., a number of milliseconds), or other suitable time resources. In some aspects, the first resources may include frequency resources. For example, the frequency resources may include subchannel(s), frequency bands, resource block set(s), frequency interlace(s), bandwidth part(s), or other suitable frequency resources.

[0102] At action 820, the method 800 includes the first sidelink UE selecting second resources from the resource pool. In this regard, the first sidelink UE may select second resources for transmitting (e.g., retransmitting) the TB in a second PSSCH. The second resources may include time resources. For example, the time resources may include slot(s), symbol(s), frame(s), subframe(s), time period(s) (e.g., a number of milliseconds), or other suitable time resources. In some aspects, the second resources may include frequency resources. For example, the frequency resources may include subchannel(s), frequency bands, resource block set(s), frequency interlace(s), bandwidth part(s), or other suitable frequency resources. In some aspect, the first sidelink UE may select the first and second resources from the resource pool at the same time.

[0103] At action 830, the method 800 includes the first sidelink UE (e.g., the sidelink transmitting UE) jointly mapping the first resources and the second resources to a same size of nominal resources. For example, the first sidelink UE may store a lookup table (e.g., store in memory 604) that maps the first resources and the second resources to a nominal resource size (e.g., a single resource size). In some aspects, the size of the nominal resources may be equal to the smaller of the size of the first resources or the size of the second resources. The size of the nominal resources may be selected such that the size of the first resources and the second resources are the same. For example, the first resources may include 5 resource blocks (RBs) while the second resources may include 8 RBs. In this case, the nominal resources may be 5 RBs corresponding to the smaller of the first and second resources. In some aspects, the second sidelink UE (e.g., the sidelink receiving UE) may also store the lookup table (e.g., the same lookup table as stored in the sidelink transmitting UE). The second sidelink UE may receive an indication of the first resources and the second resources and jointly map the first resources and the second resources to a same size of nominal resources. The second sidelink UE may similarly determine the TB size based on the nominal resources indicated by the lookup table.

[0104] In some aspects, the lookup table may indicate a TB size that maps (e.g., corresponds) to the size of the nominal resources. In some aspects, the lookup table may be preconfigured in the first and/or second sidelink UEs. Additionally or alternatively, the first and/or second sidelink UEs may receive the lookup table from a network unit (e.g., the network unit 700, the BS 105, the RU 240, the DU 230, and/or the CU 210). In some aspects, the mapping of the TB size to the nominal resources may be based on the number of resource block (RB) sets in the nominal resources, the number of subchannels in the nominal resources, and/or the number of frequency interlaces in the nominal resources. The second sidelink UE may use the same TB size for decoding both an initial transmission from the first sidelink UE and a retransmission of the TB from the first sidelink UE (e.g., a second transmission of the TB, a third transmission of the TB, etc.). In some aspects, the first sidelink UE may decide whether to use a nominal resource size for determining the TB size of the transmissions. When the first sidelink UE decides to use the lookup table procedure, the first sidelink UE may transmit an indicator to the second sidelink UE indicating that the first and second sidelink UEs should use the lookup table procedure. In this regard, the first sidelink UE may transmit the indicator in SCI (e.g., SCI-1 and/or SCI-2). In some aspects, the indicator may include a single bit field to indicate whether the first and second sidelink UEs should use the lookup table procedure. However, if the second sidelink UE fails to receive the first sidelink communication (e.g., the initial TB transmission) including the indicator in the SCI, the second sidelink UE may be unable to determine the TB size. Additionally or alternatively, the first sidelink UE may transmit an indicator to the second sidelink UE indicating the TB size. In this regard, the first sidelink UE may transmit the TB size indicator in SCI (e.g., SCI-1 and/or SCI-2). The first sidelink UE may transmit the TB size indicator in the first transmission of the TB and in all retransmissions of the TB. The indicator may explicitly indicate the TB size (e.g., the absolute TB size). Additionally or alternatively, the indicator may indicate the TB size as an offset from a reference TB size (e.g., a preconfigured/default TB size). The size of the TB may be based on the offset from the reference TB size. For example, the second sidelink UE may determine the TB size by adding or subtracting the offset from the reference TB size.

[0105] Additionally or alternatively, the first sidelink UE may transmit a PSFCH overhead indicator to the second sidelink UE indicating a resource size inconsistency due to the second resources including PSFCH resources. In some aspects, the PSFCH overhead indicator may include a single bit field to indicate a resource size inconsistency due to the second resources including PSFCH resources. In this regard, the first sidelink UE may transmit the PSFCH overhead indicator in SCI (e.g., SCI-1 and/or SCI-2). The PSFCH overhead indicator may be transmitted in addition to the indicator indicating that the first and second sidelink UEs should use the lookup table procedure. Transmitting both indicators may allow for PSFCH induced resource inconsistencies and non-PSFCH induced resource inconsistencies to be treated independently. The non-PSFCH induced resource inconsistencies may include resource inconsistencies due to operation in unlicensed frequencies, frequency interlaces having different sizes, frequency interlaces over guard bands, and/or LBT uncertainty. The PSFCH induced resource inconsistencies may be due to the second resources including PSFCH resources.

[0106] Additionally or alternatively, the first sidelink UE may transmit an implicit indicator to the second sidelink UE indicating a resource size inconsistency. For example, the implicit indicator may include a physical sidelink control channel (PSCCH) scrambling sequence, a demodulation reference signal (DMRS) sequence, a resource element pattern, and/or other suitable implicit indicator.

[0107] In some aspects, the first sidelink UE (e.g., the sidelink transmitting UE) may select the first resources from the resource pool and then select the second resources from the resource pool to be the same size as the first resources. The first sidelink UE may select the first resources by excluding resources from the resource pool whose size is not sufficient to support transmitting the TB. The first sidelink UE may select the first and second resources from the resources remaining after excluding the resources that are not sufficient to support transmitting the TB. The first sidelink UE may then select first and second resources from the remaining resources that have the same size. For example, the TB may require two frequency interlaces over one RB set or over two RB sets. The first sidelink UE may exclude resources over one RB set and select first and second resources that include two frequency interlaces over two RB sets. Alternatively, the first sidelink UE may exclude resources over two RB sets and select (e.g., randomly select) first and second resources that include two frequency interlaces over one RB set. [0108] Additionally or alternatively, the first sidelink UE (e.g., the sidelink transmitting UE) may select the first resources from the resource pool using a multi-step procedure. The first sidelink UE may initially randomly select first resources that are sufficient to support transmitting the TB. The first sidelink UE may then select the second resources by excluding resources from the resource pool that do not match the size of the first resources. The first sidelink UE may then randomly select the second resources from the remaining resources in the resource pool. The first sidelink UE may repeat this process to select resources for additional retransmissions of the TB. In some aspects, if there are not enough remaining resources in the resource pool that match the size of the first resources, the first sidelink UE may restrict the number of retransmissions based on the amount of remaining resources that match the size of the first resource. Additionally or alternatively, the first sidelink UE may repeat the multi-step selection process by excluding the initially selected first resources. Additionally or alternatively, the first sidelink UE may repeat the process by introducing resources into the resource pool that have been previously excluded by other UE’s resource reservations.

[0109] At action 840, the method 800 includes the first sidelink UE transmitting a first sidelink communication including the TB to the second sidelink UE. In this regard, the first sidelink UE may transmit a first PSSCH communication using the first resources. The first sidelink communication may include the indicator indicating the second resources and/or an indicator indicating the size of the TB. The indicator indicating the size of the TB may be either the look-up table activated indicator or the explicit size of TB indicator. The indicator(s) may be included in SCI-1 and/or SCI-2. The first sidelink communication including the TB may be an initial transmission of the TB.

[0110] At action 850, the method 800 includes the first sidelink UE transmitting a second sidelink communication including the TB to the second sidelink UE. In this regard, the first sidelink UE may transmit a second PSSCH communication using the second resources. The second sidelink communication may include the indicator indicating the second resources and/or an indicator indicating the size of the TB. The indicator(s) may be included in SCI-1 and/or SCI-2. The second sidelink communication including the TB may be a retransmission of the TB. In some aspects, the first sidelink communication may not be correctly decoded by the second sidelink UE. The second sidelink UE may transmit a NACK to the first sidelink UE indicating the first sidelink communication was not correctly decoded. In response, the first sidelink UE may retransmit the TB in the second sidelink communication. The second sidelink communication may not be correctly decoded by the second sidelink UE. The second sidelink UE may transmit a NACK to the first sidelink UE indicating the second sidelink communication was not correctly decoded. In response, the first sidelink UE may retransmit the TB in a third sidelink communication. In some aspects, the second sidelink UE may combine the first transmission of the TB and the retransmission(s) of the TB in order to increase the probability of correctly decoding the TB. The second sidelink UE may combine the initial transmission and the retransmission(s) based on the same TB size for all transmissions.

[0111] In some aspects, the first and second sidelink UEs may operate in an unlicensed frequency band. The first sidelink UE may perform a listen-before-talk (LBT) procedure prior to transmitting in the unlicensed band. In some aspects, the first sidelink UE may perform a successful LBT procedure before transmitting the first sidelink communication in the first resources. However, if the first sidelink UE performs an unsuccessful LBT prior to the second sidelink communication, the second resources may longer be available and the first sidelink UE may reselect the second resources. In some aspects, the reselected resources may not be the same size as the originally selected second resources. In this case, the first sidelink UE may reselect second resources by excluding resources of a size that will result in an invalid code rate (e.g., a code rate less than 120). [0112] FIG. 9 is a flow diagram of a communication method 900 according to some aspects of the present disclosure. Aspects of the method 900 can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device or other suitable means for performing the actions. For example, a wireless communication device, such as the UE 115 or the UE 600, may utilize one or more components, such as the processor 602, the memory 604, the variable subchannel module 608, the transceiver 610, the modem 612, and the one or more antennas 616, to execute aspects of method 900. The method 900 may employ similar mechanisms as in the networks 100 and 200 and the aspects and actions described with respect to FIGS. 3-5. As illustrated, the method 900 includes a number of enumerated actions, but the method 900 may include additional actions before, after, and in between the enumerated actions. In some aspects, one or more of the enumerated actions may be omitted or performed in a different order.

[0113] At action 910, the method 900 includes the first sidelink UE (e.g., the sidelink transmitting UE) jointly mapping first resources and second resources to a same size of nominal resources. The first sidelink UE may receive an indication of the first resources and the second resources from a second sidelink UE. In some aspects, the first sidelink UE may store a lookup table (e.g., store in memory 604) that maps the first resources and the second resources to a nominal resource size (e.g., a single resource size). In some aspects, the size of the nominal resources may be equal to the smaller of the size of the first resources or the size of the second resources. The size of the nominal resources may be selected by the second sidelink UE (e.g., the transmitting sidelink UE) such that the size of the first resources and the second resources are the same. For example, the first resources may include 5 resource blocks (RBs) while the second resources may include 8 RBs. In this case, the nominal resources may be 5 RBs corresponding to the smaller of the first and second resources. In some aspects, the second sidelink UE (e.g., the sidelink transmitting UE) may also store the lookup table (e.g., the same lookup table as stored in the sidelink receiving UE). The first sidelink UE may receive an indication of the first resources and the second resources and jointly map the first resources and the second resources to a same size of nominal resources. The first sidelink UE may similarly determine the TB size based on the nominal resources indicated by the lookup table.

[0114] In some aspects, the lookup table may indicate a TB size that maps (e.g., corresponds) to the size of the nominal resources. In some aspects, the lookup table may be preconfigured in the first and/or second sidelink UEs. Additionally or alternatively, the first and/or second sidelink UEs may receive the lookup table from a network unit (e.g., the network unit 700, the BS 105, the RU 240, the DU 230, and/or the CU 210). In some aspects, the mapping of the TB size to the nominal resources may be based on the number of resource block (RB) sets in the nominal resources, the number of subchannels in the nominal resources, and/or the number of frequency interlaces in the nominal resources. The first sidelink UE may use the same TB size for decoding both an initial transmission from the second sidelink UE and a retransmission of the TB from the second sidelink UE (e.g., a second transmission of the TB, a third transmission of the TB, etc.). In some aspects, the second sidelink UE may decide whether to use a nominal resource size for determining the TB size of the transmissions. When the second sidelink UE decides to use the lookup table procedure, the second sidelink UE may transmit an indicator to the first sidelink UE indicating that the first and second sidelink UEs should use the lookup table procedure. In this regard, the first sidelink UE may receive the indicator in SCI (e.g., SCI-1 and/or SCI-2). In some aspects, the indicator may include a single bit field to indicate whether the first and second sidelink UEs should use the lookup table procedure. However, if the first sidelink UE fails to receive the first sidelink communication (e.g., the initial TB transmission) including the indicator in the SCI, the first sidelink UE may be unable to determine the TB size. Additionally or alternatively, the first sidelink UE may receive an indicator from the second sidelink UE indicating the TB size. In this regard, the first sidelink UE may receive the TB size indicator in SCI (e.g., SCI-1 and/or SCI-2). The first sidelink UE may receive the TB size indicator in the first transmission of the TB and in all retransmissions of the TB. The indicator may explicitly indicate the TB size (e.g., the absolute TB size). Additionally or alternatively, the indicator may indicate the TB size as an offset from a reference TB size (e.g., a preconfigured/default TB size). The size of the TB may be based on the offset from the reference TB size. For example, the first sidelink UE may determine the TB size by adding or subtracting the offset from the reference TB size.

[0115] Additionally or alternatively, the first sidelink UE may receive a PSFCH overhead indicator from the second sidelink UE indicating a resource size inconsistency due to the second resources including PSFCH resources. In some aspects, the PSFCH overhead indicator may include a single bit field to indicate a resource size inconsistency due to the second resources including PSFCH resources. In this regard, the first sidelink UE may receive the PSFCH overhead indicator in SCI (e.g., SCI-1 and/or SCI-2). The PSFCH overhead indicator may be received in addition to the indicator indicating that the first and second sidelink UEs should use the lookup table procedure. The first sidelink UE receiving both indicators may allow for PSFCH induced resource inconsistencies and non-PSFCH induced resource inconsistencies to be treated independently. The non-PSFCH induced resource inconsistencies may include resource inconsistencies due to operation in unlicensed frequencies, frequency interlaces having different sizes, frequency interlaces over guard bands, and/or LBT uncertainty. The PSFCH induced resource inconsistencies may be due to the second resources including PSFCH resources.

[0116] Additionally or alternatively, the first sidelink UE may receive an implicit indicator from the second sidelink UE indicating a resource size inconsistency. For example, the implicit indicator may include a physical sidelink control channel (PSCCH) scrambling sequence, a demodulation reference signal (DMRS) sequence, a resource element pattern, and/or other suitable implicit indicator.

[0117] In some aspects, the second sidelink UE (e.g., the sidelink transmitting UE) may select the first resources from the resource pool and then select the second resources from the resource pool to be the same size as the first resources. The second sidelink UE may select the first resources by excluding resources from the resource pool whose size is not sufficient to support transmitting the TB. The second sidelink UE may select the first and second resources from the resources remaining after excluding the resources that are not sufficient to support transmitting the TB. The second sidelink UE may then select first and second resources from the remaining resources that have the same size. For example, the TB may require two frequency interlaces over one RB set or over two RB sets. The second sidelink UE may exclude resources over one RB set and select first and second resources that include two frequency interlaces over two RB sets. Alternatively, the second sidelink UE may exclude resources over two RB sets and select (e.g., randomly select) first and second resources that include two frequency interlaces over one RB set.

[0118] Additionally or alternatively, the second sidelink UE (e.g., the sidelink transmitting UE) may select the first resources from the resource pool using a multi-step procedure. The second sidelink UE may initially randomly select first resources that are sufficient to support transmitting the TB. The second sidelink UE may then select the second resources by excluding resources from the resource pool that do not match the size of the first resources. The second sidelink UE may then randomly select the second resources from the remaining resources in the resource pool. The second sidelink UE may repeat this process to select resources for additional retransmissions of the TB. In some aspects, if there are not enough remaining resources in the resource pool that match the size of the first resources, the second sidelink UE may restrict the number of retransmissions based on the amount of remaining resources that match the size of the first resource. Additionally or alternatively, the second sidelink UE may repeat the multi-step selection process by excluding the initially selected first resources. Additionally or alternatively, the second sidelink UE may repeat the process by introducing resources into the resource pool that have been previously excluded by other UE’s resource reservations.

[0119] At action 920, the method 900 includes the first sidelink UE receiving a first sidelink communication including the TB from the second sidelink UE. In this regard, the first sidelink UE may receive a first PSSCH communication using the first resources. The first sidelink communication may include the indicator indicating the second resources and/or an indicator indicating the size of the TB. The indicator(s) may be included in SCI-1 and/or SCI-2. The first sidelink communication including the TB may be an initial transmission of the TB.

[0120] At action 930, the method 900 includes the first sidelink UE receiving a second sidelink communication including the TB from the second sidelink UE. In this regard, the second sidelink UE may receive a second PSSCH communication using the second resources. The second sidelink communication may include the indicator indicating the second resources and/or an indicator indicating the size of the TB. The indicator(s) may be included in SCI-1 and/or SCI-2. The second sidelink communication including the TB may be a retransmission of the TB. In some aspects, the first sidelink communication may not be correctly decoded by the first sidelink UE. The first sidelink UE may transmit a NACK to the second sidelink UE indicating the first sidelink communication was not correctly decoded. In response, the second sidelink UE may retransmit the TB in the second sidelink communication. The second sidelink communication may not be correctly decoded by the first sidelink UE. The first sidelink UE may transmit a NACK to the second sidelink UE indicating the second sidelink communication was not correctly decoded. In response, the second sidelink UE may retransmit the TB in a third sidelink communication. In some aspects, the first sidelink UE may combine the first transmission of the TB and the retransmission(s) of the TB in order to increase the probability of correctly decoding the TB. The first sidelink UE may combine the initial transmission and the retransmission(s) based on the same TB size for all transmissions.

[0121] In some aspects, the first and second sidelink UEs may operate in an unlicensed frequency band. The second sidelink UE may perform a listen-before-talk (LBT) procedure prior to transmitting in the unlicensed band. In some aspects, the second sidelink UE may perform a successful LBT procedure before transmitting the first sidelink communication in the first resources. However, if the second sidelink UE performs an unsuccessful LBT prior to the second sidelink communication, the second resources may longer be available and the second sidelink UE may reselect the second resources. In some aspects, the reselected resources may not be the same size as the originally selected second resources. In this case, the second sidelink UE may reselect second resources by excluding resources of a size that will result in an invalid code rate (e.g., a code rate less than 120).

[0122] Further aspects of the present disclosure include the following:

[0123] Aspect 1 includes a method of wireless communication performed by a first sidelink user equipment (UE), the method comprising selecting first resources from a resource pool; selecting second resources from the resource pool; jointly mapping the first resources and the second resources to a same size of nominal resources; transmitting, to a second sidelink UE using the first resources, a first sidelink communication including a transport block (TB) and an indicator indicating the second resources; and transmitting, to the second sidelink UE using the second resources, a second sidelink communication including the TB, wherein a size of the TB is based on at least the size of the nominal resources.

[0124] Aspect 2 includes the method of aspect 1, further comprising selecting a first modulation and coding scheme (MCS) based on the first resources; and selecting a second MCS based on the second resources, wherein the transmitting the first sidelink communication comprises transmitting the first sidelink communication based on the first MCS ; and the transmitting the second sidelink communication comprises transmitting the second sidelink communication based on the second MCS.

[0125] Aspect 3 includes the method of any of aspects 1-2, wherein at least one of the first resources or the second resources comprise a first frequency interlace over multiple contiguous resource block sets and a guard band separating the contiguous resource block sets. [0126] Aspect 4 includes the method of any of aspects 1-3, wherein at least one of the first resources or the second resources comprise a first frequency interlace over a single resource block set and a second frequency interlace over the single resource block set. [0127] Aspect 5 includes the method of any of aspects 1-4, further comprising selecting the first resources from a resource pool; selecting the second resources from the resource pool; and mapping the first resources and the second resources to nominal resources, wherein the size of the TB is further based on the nominal resources.

[0128] Aspect 6 includes the method of any of aspects 1-5, wherein the mapping is based on a lookup table.

[0129] Aspect 7 includes the method of any of aspects 1-6, wherein the nominal resources include the smaller of the first resources or the second resource.

[0130] Aspect 8 includes the method of any of aspects 1-7, wherein the first sidelink communication further indicates third resources; and the method further comprises transmitting, to the second sidelink UE using the third resources, a third sidelink communication including the TB.

[0131] Aspect 9 includes the method of any of aspects 1-8, further comprising selecting the first resources from a resource pool; and selecting the second resources from the resource pool, wherein a size of the second resources is a same size as a size of the first resources.

[0132] Aspect 10 includes the method of any of aspects 1-9, wherein the selecting first resources comprises excluding resources from the resource pool that do not support transmitting the TB; and the selecting the second resources comprises excluding resources from the resource pool that are not of a same size as the first resources.

[0133] Aspect 11 includes the method of any of aspects 1-10, wherein the selecting first resources comprises randomly selecting the first resources from the resource pool that support transmitting the TB; and the selecting second resources comprises excluding resources from the resource pool that do not match a size of the first resources; and randomly selecting the second resources from resources of the resource pool remaining after excluding the resources that do not match the size of the first resources.

[0134] Aspect 12 includes the method of any of aspects 1-11, wherein the first sidelink communication includes a code point in sidelink control information (SCI) indicating the second resources are based on a nominal resource size; and the size of the TB is based on the nominal resource size. [0135] Aspect 13 includes the method of any of aspects 1-12, wherein the first sidelink communication comprises first sidelink control information (SCI) indicating the size of the TB; and the second sidelink communication comprises second SCI indicating the size of the TB.

[0136] Aspect 14 includes the method of any of aspects 1-13, wherein the first sidelink communication comprises first sidelink control information (SCI) indicating an offset from a reference TB size; the second sidelink communication comprises second SCI indicating the offset from the reference TB size; and the size of the TB is based on the offset from the reference TB size.

[0137] Aspect 15 includes the method of any of aspects 1-14, wherein the indicator indicating the second resources indicates that the second resources include physical sidelink feedback channel (PSFCH) resources; and a size of the first resources is a same size as the second resources.

[0138] Aspect 16 includes the method of any of aspects 1-15, wherein the indicator comprises at least one of a code point in sidelink control information (SCI); a physical sidelink control channel (PSCCH) scrambling sequence; a demodulation reference signal (DMRS) sequence; or a resource element pattern.

[0139] Aspect 17 includes the method of any of aspects 1-16, further comprising performing a first listen-before talk (LBT) procedure, wherein the transmitting the first sidelink communication comprises transmitting the first sidelink communication based on the LBT procedure being successful; performing a second LBT procedure; selecting, based on the second LBT procedure being unsuccessful, the second resources from a resource pool; and performing a third LBT procedure, wherein the transmitting the second sidelink communication comprises transmitting the second sidelink communication based on the third LBT procedure being successful.

[0140] Aspect 18 method of wireless communication performed by a first sidelink user equipment (UE), the method comprising jointly mapping first resources and second resources to a same size of nominal resources; receiving, from a second sidelink UE using the first resources, a first sidelink communication including a transport block (TB) and an indicator indicating the second resources; and receiving, from the second sidelink UE using the second resources, a second sidelink communication including the TB, wherein a size of the TB is based on at least the size of the nominal resources.

[0141] Aspect 19 includes the method of aspect 18, further comprising selecting a first modulation and coding scheme (MCS) based on the first resources; and selecting a second MCS based on the second resources, wherein the receiving the first sidelink communication comprises receiving the first sidelink communication based on the first MCS; and the receiving the second sidelink communication comprises receiving the second sidelink communication based on the second MCS.

[0142] Aspect 20 includes the method of any of aspects 18-19, wherein at least one of the first resources or the second resources comprise a first frequency interlace over multiple contiguous resource block sets and a guard band separating the contiguous resource block sets.

[0143] Aspect 21 includes the method of any of aspects 18-20, wherein at least one of the first resources or the second resources comprise a first frequency interlace over a single resource block set and a second frequency interlace over the single resource block set.

[0144] Aspect 22 includes the method of any of aspects 18-21, further comprising mapping the first resources and the second resources to nominal resources, wherein the size of the TB is further based on the nominal resources.

[0145] Aspect 23 includes the method of any of aspects 18-22, wherein the mapping is based on a lookup table.

[0146] Aspect 24 includes the method of any of aspects 18-23, wherein the nominal resources include the smaller of the first resources or the second resources.

[0147] Aspect 25 includes the method of any of aspects 18-24, wherein the first sidelink communication further indicates third resources; and the method further comprises receiving, from the second sidelink UE using the third resources, a third sidelink communication including the TB.

[0148] Aspect 26 includes the method of any of aspects 18-25, wherein the first resources are selected from a resource pool; and the second resources are selected from the resource pool, wherein a size of the second resources is a same size as a size of the first resources.

[0149] Aspect 27 includes the method of any of aspects 18-26, wherein the first sidelink communication includes a code point in sidelink control information (SCI) indicating the second resources are based on a nominal resource size; and the size of the TB is based on the nominal resource size.

[0150] Aspect 28 includes the method of any of aspects 18-27, wherein the first sidelink communication comprises first sidelink control information (SCI) indicating the size of the TB; and the second sidelink communication comprises second SCI indicating the size of the TB.

[0151] Aspect 29 includes the method of any of aspects 18-28, wherein the first sidelink communication comprises first sidelink control information (SCI) indicating an offset from a reference TB size; the second sidelink communication comprises second SCI indicating the offset from the reference TB size; and the size of the TB is based on the offset from the reference TB size.

[0152] Aspect 30 includes the method of any of aspects 18-29, wherein the indicator indicating the second resources indicates that the second resources include physical sidelink feedback channel (PSFCH) resources; and a size of the first resources is a same size as the second resources.

[0153] Aspect 31 includes the method of any of aspects 18-29, wherein the indicator comprises at least one of a code point in sidelink control information (SCI); a physical sidelink control channel (PSCCH) scrambling sequence; a demodulation reference signal (DMRS) sequence; or a resource element pattern.

[0154] Aspect 32 includes a non-transitory computer-readable medium storing one or more instructions for wireless communication, the one or more instructions comprising one or more instructions that, when executed by one or more processors of a first sidelink (UE) cause the first sidelink UE to perform any one of aspects 1-17.

[0155] Aspect 33 includes a non-transitory computer-readable medium storing one or more instructions for wireless communication, the one or more instructions comprising one or more instructions that, when executed by one or more processors of a second sidelink user equipment (UE), cause the second sidelink UE to perform any one of aspects 18-31.

[0156] Aspect 34 includes a first sidelink user equipment (UE) comprising one or more means to perform any one or more of aspects 1-17.

[0157] Aspect 35 includes a second sidelink user equipment (UE) comprising one or more means to perform any one or more of aspects 18-31.

[0158] Aspect 36 includes a first sidelink user equipment (UE) comprising a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, wherein the UE is configured to perform any one or more of aspects 1-17.

[0159] Aspect 37 includes a second sidelink user equipment (UE) comprising a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, wherein the second sidelink UE is configured to perform any one or more of aspects 18-31.

[0160] Information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0161] The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0162] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described above may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Also, as used herein, including in the claims, "or" as used in a list of items (for example, a list of items prefaced by a phrase such as "at least one of" or "one or more of") indicates an inclusive list such that, for example, a list of [at least one of A, B, or C] means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

[0163] As those of some skill in this art will by now appreciate and depending on the particular' application at hand, many modifications, substitutions and variations may be made in and to the materials, apparatus, configurations and methods of use of the devices of the present disclosure without departing from the spirit and scope thereof. In light of this, the scope of the present disclosure should not be limited to that of the particular instances illustrated and described herein, as they are merely by way of some examples thereof, but rather, should be fully commensurate with that of the claims appended hereafter and their functional equivalents.

Claims

WHAT IS CLAIMED IS:

1. A method of wireless communication performed by a first sidelink user equipment (UE), the method comprising: selecting first resources from a resource pool; selecting second resources from the resource pool; jointly mapping the first resources and the second resources to a same size of nominal resources; transmitting, to a second sidelink UE using the first resources, a first sidelink communication including a transport block (TB) and an indicator indicating the second resources; and transmitting, to the second sidelink UE using the second resources, a second sidelink communication including the TB, wherein a size of the TB is based on at least the size of the nominal resources.

2. The method of claim 1 , wherein the mapping is based on a lookup table.

3. The method of claim 1, wherein the size of the nominal resources equals the smaller of a size of the first resources or a size of the second resources.

4. The method of claim 1 , wherein a size of the second resources is a same size as a size of the first resources.

5. The method of claim 1, wherein: the selecting first resources comprises excluding resources from the resource pool whose size is not sufficient to support transmitting the TB ; and the selecting the second resources comprises excluding resources from the resource pool that are not of a same size as the first resources.

6. The method of claim 1 , wherein: the selecting first resources comprises: randomly selecting the first resources from the resource pool that support transmitting the TB; and the selecting second resources comprises: excluding resources from the resource pool that do not match a size of the first resources; and randomly selecting the second resources from resources of the resource pool remaining after excluding the resources that do not match the size of the first resources.

7. The method of claim 1, wherein: the first sidelink communication includes an indicator in sidelink control information (SCI) indicating the size of the TB transmitted over the first and second resources is based on the nominal resource size.

8. The method of claim 1, wherein: the first sidelink communication comprises first sidelink control information (SCI) indicating the size of the TB; and the second sidelink communication comprises second SCI indicating the size of the TB.

9. The method of claim 1 , wherein: the first sidelink communication comprises first sidelink control information (SCI) indicating an offset from a reference TB size; the second sidelink communication comprises second SCI indicating the offset from the reference TB size; and the size of the TB is based on the offset from the reference TB size.

10. A method of wireless communication performed by a first sidelink user equipment (UE), the method comprising: jointly mapping first resources and second resources to a same size of nominal resources; receiving, from a second sidelink UE using the first resources, a first sidelink communication including a transport block (TB) and an indicator indicating the second resources; and receiving, from the second sidelink UE using the second resources, a second sidelink communication including the TB, wherein a size of the TB is based on at least the size of the nominal resources.

11. The method of claim 10, wherein the mapping is based on a lookup table.

12. The method of claim 10, wherein the size of the nominal resources equals the smaller of a size of the first resources or a size of the second resources.

13. The method of claim 10, wherein the first sidelink communication further indicates third resources; and the method further comprises: receiving, from the second sidelink UE using the third resources, a third sidelink communication including the TB.

14. The method of claim 10, wherein: the first sidelink communication includes an indicator in sidelink control information (SCI) indicating the size of the TB transmitted over the first and second resources is based on the nominal resource size.

15. The method of claim 10, wherein: the first sidelink communication comprises first sidelink control information (SCI) indicating the size of the TB; and the second sidelink communication comprises second SCI indicating the size of the TB.

16. A first sidelink user equipment (UE) comprising: a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, wherein the first sidelink UE is configured to: select first resources from a resource pool; select second resources from the resource pool; jointly map the first resources and the second resources to a same size of nominal resources; transmit, to a second sidelink UE using the first resources, a first sidelink communication including a transport block (TB) and an indicator indicating the second resources; and transmit, to the second sidelink UE using the second resources, a second sidelink communication including the TB, wherein a size of the TB is based on at least the size of the nominal resources.

17. The first sidelink UE of claim 16, wherein the mapping is based on a lookup table.

18. The first sidelink UE of claim 16, wherein the size of the nominal resources equals the smaller of a size of the first resources or a size of the second resources.

19. The first sidelink UE of claim 16, wherein a size of the second resources is a same size as a size of the first resources.

20. The first sidelink UE of claim 16, wherein the first sidelink UE is further configured to: select the first resources by excluding resources from the resource pool whose size is not sufficient to support transmitting the TB; and select the second resources by excluding resources from the resource pool that are not of a same size as the first resources.

21. The first sidelink UE of claim 16, wherein the first sidelink UE is further configured to: randomly select the first resources from the resource pool that support transmitting the TB; and exclude resources from the resource pool that do not match a size of the first resources; and randomly select the second resources from resources of the resource pool remaining after excluding the resources that do not match the size of the first resources.

22. The first sidelink UE of claim 16, wherein: the first sidelink communication includes an indicator in sidelink control information (SCI) indicating the size of the TB transmitted over the first and second resources is based on the nominal resource size.

23. The first sidelink UE of claim 16, wherein: the first sidelink communication comprises first sidelink control information (SCI) indicating the size of the TB; and the second sidelink communication comprises second SCI indicating the size of the TB.

24. The first sidelink UE of claim 16, wherein: the first sidelink communication comprises first sidelink control information (SCI) indicating an offset from a reference TB size; the second sidelink communication comprises second SCI indicating the offset from the reference TB size; and the size of the TB is based on the offset from the reference TB size.

25. A first sidelink user equipment (UE) comprising: a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, wherein the first sidelink UE is configured to: jointly map first resources and second resources to a same size of nominal resources; receive, from a second sidelink UE using the first resources, a first sidelink communication including a transport block (TB) and an indicator indicating the second resources; and receive, from the second sidelink UE using the second resources, a second sidelink communication including the TB, wherein a size of the TB is based on at least the size of the nominal resources.

26. The first sidelink UE of claim 25, wherein the mapping is based on a lookup table.

27. The first sidelink UE of claim 25, wherein the size of the nominal resources equals the smaller of a size of the first resources or a size of the second resources.

28. The first sidelink UE of claim 25, wherein the first sidelink communication further indicates third resources; and the first sidelink UE is further configured to: receiving, from the second sidelink UE using the third resources, a third sidelink communication including the TB.

29. The first sidelink UE of claim 25, wherein: the first sidelink communication includes an indicator in sidelink control information (SCI) indicating the size of the TB transmitted over the first and second resources is based on the nominal resource size.

30. The first sidelink UE of claim 25, wherein: the first sidelink communication comprises first sidelink control information (SCI) indicating the size of the TB; and the second sidelink communication comprises second SCI indicating the size of the TB.