Receiver-Side Sensing for Sidelink UE Cooperation

Abstract

Disclosed herein are apparatuses, methods, and computer-readable media for facilitating SL communication for Mode 2 resource allocation. An exemplary method includes performing sensing on one or more SL resources to identify a first set of available resources. The exemplary method further includes adjusting a first measurement threshold to a second measurement threshold based on a size of the first set of available resources being less than an availability threshold. The exemplary method further includes transmitting a sidelink message indicating the second set of available resources based on the second measurement threshold.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Non-Provisional Patent Application No. 17 / 450,433, entitled “RECEIVER SIDE SENSING FOR SIDELINK INTER-UE-COORDINATION,” filed on October 8, 2021, the entirety of which is expressly incorporated herein by reference.

[0002] The present disclosure relates generally to communication systems, and more particularly to wireless communications utilizing sidelink (SL) communications between user equipment (UE). [Background technology]

[0003] Wireless communication systems have been widely deployed to provide various telecommunication services, such as telephone, video, data, messaging, and broadcast. A typical wireless communication system may utilize multiple access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems.

[0004] These multiple access technologies are being adopted in various telecommunications standards to provide a common protocol that allows different wireless devices to communicate on a city, national, regional, or even global scale. An exemplary telecommunications standard is 5G New Radio (NR). 5G NR is part of the continuing mobile broadband evolution promulgated by the 3rd Generation Partnership Project (3GPP®) to meet new requirements related to latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)), and other requirements. 5G NR includes services related to enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC). Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. Some aspects of wireless communications may include direct communication between devices based on sidelinks. There is a need for further improvements in sidelink technologies. These improvements may also be applicable to other multiple access technologies and telecommunications standards utilizing these technologies. Summary of the Invention [Means for solving the problem]

[0005] The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, nor is it intended to identify key or critical elements of all aspects or to delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0006] In an aspect of the present disclosure, a method of wireless communication in a first UE is provided. The method may include performing sensing on one or more SL resources to identify a first set of available resources. The example method may also include adjusting a first measurement threshold to a second measurement threshold based on a size of the first set of available resources being less than an availability threshold. The example method may also include transmitting a sidelink message indicating the second set of available resources based on the second measurement threshold.

[0007] In another aspect of the disclosure, an apparatus for wireless communication is provided. The apparatus may be a UE including a memory and at least one processor coupled to the memory, where the memory and the at least one processor are configured to perform sensing on one or more SL resources to identify a first set of available resources. The memory and the at least one processor may also be configured to adjust a first measurement threshold to a second measurement threshold based on a size of the first set of available resources being less than an availability threshold. The memory and the at least one processor may also be configured to transmit a sidelink message indicating the second set of available resources based on the second measurement threshold.

[0008] In another aspect of the disclosure, an apparatus for wireless communication in a wireless device is provided. The apparatus may include means for performing sensing on one or more SL resources to identify a first set of available resources. The example apparatus may also include means for adjusting a first measurement threshold to a second measurement threshold based on a size of the first set of available resources being less than an availability threshold. The example apparatus may also include means for transmitting a sidelink message indicating the second set of available resources based on the second measurement threshold.

[0009] In another aspect of the disclosure, a non-transitory computer-readable storage medium storing computer-executable code for wireless communication in a wireless device is provided. The code, when executed, may cause a processor to perform sensing on one or more SL resources to identify a first set of available resources. The example code, when executed, may also cause the processor to adjust a first measurement threshold to a second measurement threshold based on a size of the first set of available resources being less than an availability threshold. The example code, when executed, may also cause the processor to transmit a sidelink message indicating a second set of available resources based on the second measurement threshold.

[0010] In an aspect of the present disclosure, a method of wireless communication in a first UE is provided. The method may include performing sensing measurements on one or more SL resources to determine one or more available resources for sidelink communication. An example method may also include transmitting a sidelink message including a resource availability report indicating a subset of the one or more available resources.

[0011] In another aspect of the present disclosure, an apparatus for wireless communication is provided. The apparatus may be a first UE including a memory and at least one processor coupled to the memory, where the memory and the at least one processor are configured to perform sensing measurements on one or more SL resources to determine one or more available resources for sidelink communication. The memory and the at least one processor may also be configured to transmit a sidelink message including a resource availability report indicating a subset of the one or more available resources.

[0012] In another aspect of the present disclosure, an apparatus for wireless communication in a first UE is provided. The apparatus may include means for performing sensing measurements on one or more SL resources to determine one or more available resources for sidelink communication. An example apparatus may also include means for transmitting a sidelink message including a resource availability report indicating a subset of the one or more available resources.

[0013] In another aspect of the disclosure, a non-transitory computer-readable storage medium is provided that stores computer-executable code for wireless communication in a first UE. The code, when executed, may cause a processor to perform sensing measurements on one or more SL resources to determine one or more available resources for sidelink communication. Example code, when executed, may also cause the processor to transmit a sidelink message including a resource availability report indicating a subset of the one or more available resources.

[0014] To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of the various aspects may be employed and the description is intended to include all such aspects and their equivalents. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 illustrates an example of a wireless communication system and access network. [Diagram 2] 1A-1C illustrate example aspects of side link slot configurations. [Diagram 3] A diagram showing an example of a first device and a second device involved in wireless communication, e.g., based on a sidelink. [Figure 4]FIG. 1 illustrates example aspects of sidelink communication between devices according to aspects presented herein. [Diagram 5] FIG. 1 illustrates an example of resource reservation for sidelink communication. [Figure 6] FIG. 11 is a timing diagram for a UE utilizing a sensing mechanism. [Figure 7A] FIG. 1 illustrates inter-UE coordination between UEs in accordance with the teachings disclosed herein. [Figure 7B] FIG. 1 illustrates inter-UE coordination between UEs in accordance with the teachings disclosed herein. [Figure 8] FIG. 2 illustrates a communication flow between UEs in accordance with the teachings disclosed herein. [Figure 9] 1 is a flowchart of a method of wireless communication in a first UE in accordance with the teachings disclosed herein. [Figure 10] 1 is a flowchart of a method of wireless communication in a first UE in accordance with the teachings disclosed herein. [Figure 11] 1 is a flowchart of a method of wireless communication in a first UE in accordance with the teachings disclosed herein. [Figure 12] 1 is a flowchart of a method of wireless communication in a first UE in accordance with the teachings disclosed herein. [Figure 13] FIG. 2 illustrates an example hardware implementation of an exemplary apparatus in accordance with the teachings disclosed herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Sidelink communication allows a first UE to communicate directly with another UE. Sidelink communication may be based on different types or modes of resource allocation mechanisms. In a first resource allocation mode (which may be referred to herein as “Mode 1”), a centralized resource allocation may be performed by a network entity. In a second resource allocation mode (which may be referred to herein as “Mode 2”), a distributed resource allocation may be performed. In Mode 2 resource allocation, each UE may autonomously determine the resources to use for sidelink transmission. To coordinate the selection of sidelink resources by individual UEs, each UE may use sensing techniques to monitor resource reservations by other sidelink UEs and may select resources for sidelink transmission from the unreserved resources. Devices communicating based on sidelink may determine one or more radio resources in the time and frequency domain that are reserved or used by other devices to avoid selecting conflicting (e.g., time and / or frequency overlapping) transmission resources.

[0017] Thus, in the second mode (e.g., mode 2), individual UEs may autonomously select resources for sidelink transmissions without a central entity, such as a base station, indicating resources for the device. The UEs may receive various types of information that may be used for sidelink resource selection. To reduce or avoid resource collisions in such cases and to improve sidelink communication between UEs, the UEs may coordinate among themselves by generating and sharing inter-UE coordination information with other UEs. As an example, a first UE may generate inter-UE coordination information indicating preferred resources, non-preferred resources, or resource contention information. A second UE may receive inter-UE coordination information from the first UE and accordingly avoid using non-preferred resources when communicating with the first UE. In some aspects, when transmitting its own resource reservation, the second UE may include inter-UE coordination information related to the second UE based on reservation information (e.g., information indicating time and frequency resources reserved for a particular sidelink transmission) or inter-UE coordination information received from the first UE (or other UEs).

[0018] As an example, the receiving UE may perform sensing and, based on the sensing results, inform the transmitting UE (along with other UEs) about the resources available for transmission. For example, the receiving UE may be a smartphone with higher processing power and larger battery capacity than the transmitting UE, which may be a smartwatch with limited battery capacity and limited processing power. In such an example, it may be more efficient to have the more processing-capable receiving UE with a larger battery capacity perform sensing for the transmitting UE.

[0019] In some situations, based on the sensing, the receiving UE may identify a first set of available resources (e.g., by comparing the size of the available resources to an availability threshold) for transmission by the transmitting UE that may be smaller than a threshold amount of available resources. Aspects provided herein enable the receiving UE to adjust one or more parameters, such as a measurement threshold, when identifying a set of available resources that may be suitable for transmission by the transmitting UE. By enabling the receiving UE to adjust a parameter for identifying available resources, for example by adjusting a measurement threshold, the receiving UE may indicate a more consistent amount of available resources for the transmitting UE. Increasing consistency in the amount of available resources reported by the receiving UE may provide the transmitting UE with information of a set of available resources that may be more suitable for transmission.

[0020] As used herein, the term “sensing” may refer to a procedure in which a UE performs one or more measurements (which may be referred to as “sensing measurements”) to identify resources available for sidelink transmission for the UE or another UE. As an example, the sensing measurements may include a reference signal received power (RSRP) measurement, a reference signal received quality (RSRQ) measurement, a signal to interference ratio (SIR) measurement, etc. The UE may compare a sensing measurement associated with a resource to a threshold (which may be referred to as a “measurement threshold”). If the sensing measurement associated with the resource is below the measurement threshold, the UE may determine that the resource is available. In another example, if the sensing measurement associated with the resource is above the measurement threshold, the UE may determine that the resource is available. As used herein, the term “inter-UE coordination information” may refer to information exchanged between sidelink UEs to facilitate sidelink communication under resource allocation mode 2, in which each UE may autonomously determine the resources to use for sidelink transmission.

[0021] The detailed description set forth below with reference to the accompanying 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 to avoid obscuring such concepts.

[0022] Several aspects of a telecommunications system are now presented with reference to various apparatus and methods that are described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the particular application and design constraints imposed on the overall system.

[0023] As an example, an element or any portion of an element or any combination of elements may be implemented as a "processing system" including one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on chips (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gate logic, discrete hardware circuits, and other suitable hardware configured to perform various functions described throughout this disclosure. One or more processors in a processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, and the like, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0024] Thus, in one or more examples, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. A storage medium may be any available medium that can be accessed by a computer. By way of example and not limitation, such computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of types of computer-readable media, or any other medium that can be used to store computer-executable code in the form of instructions or data structures that can be accessed by a computer.

[0025] Although aspects and implementations are described in this application by illustrating some examples, those skilled in the art will understand that additional implementations and use cases may arise in many different configurations and scenarios. The aspects described herein may be implemented across many different platform types, devices, systems, shapes, sizes, and packaging configurations. For example, implementations and / or applications may arise with integrated chip implementations and other non-modular component-based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchasing devices, medical devices, artificial intelligence (AI)-enabled devices, etc.). Some examples may or may not be specifically targeted to a use case or application, but a wide variety of applicability of the described aspects may arise. Implementations may range from chip-level or modular components to non-modular, non-chip-level implementations, and even aggregated, distributed, or original equipment manufacturer (OEM) devices or systems that incorporate one or more of the described aspects. In some practical settings, devices incorporating the described aspects and features may also include additional components and features for implementing and practicing the claimed and described aspects. For example, transmitting and receiving wireless signals necessarily includes several components for analog and digital purposes (e.g., hardware components including antennas, RF chains, power amplifiers, modulators, buffers, processors, interleavers, adders / summers, etc.). It is intended that the aspects described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed configurations, end-user devices, etc., of various sizes, shapes, and configurations.

[0026] 1 is a diagram illustrating an example of a wireless communication system and access network 100. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes a base station 102, a UE 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., 5G core (5GC)). The base station 102 may include a macro cell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). The macro cell includes a base station. The small cell includes a femto cell, a pico cell, and a micro cell.

[0027] The link between the UE 104 and the base station 102 or 180 may be established as an access link, for example, using the Uu interface. Other communications may be exchanged between wireless devices based on the sidelink. For example, some UEs 104 may communicate directly with each other using device-to-device (D2D) communication links 158. In some examples, the D2D communication links 158 may use DL / UL WWAN spectrum. The D2D communication links 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). The D2D communication may be through various wireless D2D communication systems, such as, for example, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

[0028] Some examples of sidelink communications may include vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I) (e.g., from a vehicle-based communications device to a road infrastructure node such as a roadside unit (RSU)), vehicle-to-network (V2N) (e.g., from a vehicle-based communications device to one or more network nodes such as a base station), vehicle-to-pedestrian (V2P), cellular vehicle-to-everything (C-V2X), and / or combinations thereof, which may be collectively referred to as vehicle-to-anything (V2X) communications, and / or vehicle-based communications devices that may communicate from and / or with other devices. Sidelink communications may be based on V2X communications or other D2D communications such as Proximity Services (ProSe), etc. In addition to UEs, sidelink communications may also be transmitted and received by other transmitting and receiving devices, such as road side units (RSUs) 107. Sidelink communications may be exchanged using a PC5 interface, such as that described in connection with the example of FIG. 2. In some examples, an intermediate device (e.g., such as a base station 102 or 180) may facilitate communication between an originating device (e.g., a first UE) and a target device (e.g., a second UE) using sidelink communications. For example, in some examples, the base station may allocate resources for sidelink communications. In other examples, the devices may communicate without assistance from intermediate devices.

[0029] The following description, including the example slot structure of FIG. 2, may provide an example of sidelink communications related to 5G NR, although the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0030] Referring again to FIG. 1, in some aspects, a sidelink communication device, such as a UE 104, may be configured to manage one or more aspects of wireless communication by facilitating resource reservation for a UE employing a power saving mode. By way of example, in FIG. 1, the UE 104 may include an SL component 198 configured to perform sensing on one or more SL resources to identify a first set of available resources. The SL component 198 may also be configured to adjust a first measurement threshold to a second measurement threshold based on a size of the first set of available resources being less than an availability threshold. The SL component 198 may also be configured to transmit a sidelink message indicating a second set of available resources based on the second measurement threshold. The SL component 198 may also be configured to perform sensing measurements on one or more SL resources to determine one or more available resources for sidelink communication. The SL component 198 may also be configured to transmit a sidelink message including a resource availability report indicating a subset of the one or more available resources.

[0031] Although the following description provides examples directed to 5G NR (and, specifically, sidelink communications over 5G NR), the concepts described herein may be applicable to other similar domains, such as LTE, LTE-A, CDMA, GSM, and / or other wireless technologies, in which wireless communication devices may utilize power saving modes to perform resource reservation.

[0032] A base station 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC 160 over a first backhaul link 132 (e.g., an S1 interface). A base station 102 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN)) may interface with the core network 190 over a second backhaul link 184. In addition to other functions, the base stations 102 may perform one or more of the following functions: forwarding user data, encryption and decryption of radio channels, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment tracking, RAN information management (RIM), paging, positioning, and delivery of alert messages. The base stations 102 may communicate with each other directly or indirectly (e.g., through the EPC 160 or the core network 190) via the third backhaul link 134 (e.g., X2 interface). The first backhaul link 132, the second backhaul link 184 (e.g., Xn interface), and the third backhaul link 134 may be wired or wireless.

[0033] In some aspects, the base station 102 or 180 may be referred to as a RAN and may include aggregated or disaggregated components. As an example of a disaggregated RAN, as shown in FIG. 1, the base station may include a central unit (CU) 106, one or more distributed units (DUs) 105, and / or one or more remote units (RUs) 109. The RAN may be disaggregated with a split between the RU 109 and an aggregated CU / DU. The RAN may be disaggregated with a split between the CU 106, the DU 105, and the RU 109. The RAN may be disaggregated with a split between the CU 106 and an aggregated DU / RU. The CU 106 and one or more DUs 105 may be connected via an F1 interface. The DUs 105 and the RUs 109 may be connected via a fronthaul interface. The connection between the CU 106 and the DUs 105 may be referred to as a midhaul, and the connection between the DUs 105 and the RUs 109 may be referred to as a fronthaul. The connection between the CU 106 and the core network may be referred to as a backhaul. The RAN may be based on a functional division between various components of the RAN, e.g., the CU 106, the DU 105, or the RU 109. The CU may be configured to execute one or more aspects of the wireless communication protocol, e.g., handle one or more layers of a protocol stack, and the DU may be configured to handle other aspects of the wireless communication protocol, e.g., other layers of the protocol stack. In different implementations, the division between the layers handled by the CU and the layers handled by the DU may be at different layers of the protocol stack. As one non-limiting example, the DU 105 may provide logical nodes for hosting at least a portion of a radio link control (RLC) layer, a medium access control (MAC) layer, and a physical (PHY) layer, based on the functional division. The RU may provide a logical node configured to host at least a portion of the PHY layer and radio frequency (RF) processing. The CU 106 may host higher layer functions, for example, layer functions above the RLC layer, such as a Service Data Adaptation Protocol (SDAP) layer, a Packet Data Convergence Protocol (PDCP) layer, etc.In other implementations, the division of layer functionality provided by the CU, DU, or RU may be different.

[0034] An access network may include one or more IAB nodes 111 that exchange wireless communications with UEs 104 or other integrated access and backhaul (IAB) nodes 111 to provide access and backhaul to a core network. In an IAB network with multiple IAB nodes, an anchor node may be called an IAB donor. An IAB donor may be a base station 102 or 180 that provides access to a core network 190 or an EPC 160 and / or provides control to one or more IAB nodes 111. An IAB donor may include a CU 106 and a DU 105. An IAB node 111 may include a DU 105 and a mobile termination (MT). The DU 105 of an IAB node 111 may act as a parent node, and the MT may act as a child node.

[0035] The base stations 102 may communicate wirelessly with the UE 104. Each of the base stations 102 may provide communication coverage to a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, a small cell 102' may have a coverage area 110' that overlaps with the coverage area 110 of one or more macro base stations 102. A network including both small cells and macro cells may be known as a heterogeneous network. A heterogeneous network may also include a Home Evolved Node B (eNB) (HeNB) that may serve restricted groups known as Closed Subscriber Groups (CSGs). A communication link 120 between the base station 102 and the UE 104 may include uplink (UL) (also referred to as reverse link) transmissions from the UE 104 to the base station 102 and / or downlink (DL) (also referred to as forward link) transmissions from the base station 102 to the UE 104. The communication link 120 may use multiple-input multiple-output (MIMO) antenna techniques, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link may be through one or more carriers. The base station 102 / UE 104 may use spectrum with bandwidth up to Y MHz (e.g., 5, 10, 15, 20, 100, 400 MHz, etc.) per carrier allocated in carrier aggregation with up to a total of Yx MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. The carrier allocation may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​than UL). The component carriers may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell), and the secondary component carrier may be referred to as a secondary cell (SCell).

[0036] The wireless communication system may further include a Wi-Fi access point (AP) 150 in communication with a Wi-Fi station (STA) 152 via a communication link 154, such as in the 5 GHz unlicensed frequency spectrum. When communicating in the unlicensed frequency spectrum, the STA 152 / AP 150 may perform clear channel assessment (CCA) before communicating to determine if a channel is available.

[0037] The small cell 102' may operate in a licensed and / or unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102' may utilize NR and use the same unlicensed frequency spectrum (e.g., 5 GHz, etc.) used by the Wi-Fi AP 150. The small cell 102' utilizing NR in the unlicensed frequency spectrum may increase coverage to and / or adjust capacity of the access network.

[0038] The electromagnetic spectrum is often subdivided into various classes, bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating bands have been identified as frequency range designations FR1 (410 MHz - 7.125 GHz) and FR2 (24.25 GHz - 52.6 GHz). Although a portion of FR1 is higher than 6 GHz, FR1 is often referred to (interchangeably) as the "sub-6 GHz" band in various documents and papers. Similar nomenclature issues may arise with respect to FR2, which is often referred to (interchangeably) as the "mmWave" band in documents and papers, even though it is different from the extremely high frequency (EHF) bands (30 GHz - 300 GHz) identified as "mmWave" bands by the International Telecommunications Union (ITU).

[0039] Frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Recent 5G NR studies have identified the operating bands for these mid-band frequencies as frequency range designation FR3 (7.125 GHz to 24.25 GHz). Frequency bands that fall within FR3 may inherit FR1 and / or FR2 characteristics, thus effectively extending the features of FR1 and / or FR2 to the mid-band frequencies. In addition, higher frequency bands are currently being considered to extend 5G NR operation beyond 52.6 GHz. For example, three higher operating bands have been identified as frequency range designations FR4a or FR4-1 (52.6 GHz to 71 GHz), FR4 (52.6 GHz to 114.25 GHz), and FR5 (114.25 GHz to 300 GHz). Each of these higher frequency bands falls within the EHF band.

[0040] With the above aspects in mind, it should be understood that unless otherwise specified, terms such as "sub-6 GHz," as used herein, may broadly refer to frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies. Additionally, it should be understood that unless otherwise specified, terms such as "mmWave," as used herein, may broadly refer to frequencies that may be within FR2, FR4, FR4-a or FR4-1, and / or FR5, which may include mid-band frequencies, or may be within the EHF band.

[0041] The base station 102, whether a small cell 102′ or a large cell (e.g., a macro base station), may include and / or be referred to as an eNB, gNodeB (gNB), or another type of base station. Some base stations, such as the gNB 180, may operate at millimeter wave and / or quasi-millimeter wave frequencies in the conventional sub-6 GHz spectrum in communication with the UE 104. When the gNB 180 operates at millimeter wave or quasi-millimeter wave frequencies, the gNB 180 may be referred to as a millimeter wave base station. The millimeter wave base station 180 may utilize beamforming 182 to the UE 104 to compensate for path loss and short distances. The base station 180 and the UE 104 may each include multiple antennas, such as antenna elements, antenna panels, and / or antenna arrays, to facilitate beamforming. Similarly, beamforming may be applied, for example, for sidelink communications between UEs.

[0042] The base station 180 may transmit a beamformed signal to the UE 104 in one or more transmit directions 182′. The UE 104 may receive a beamformed signal from the base station 180 in one or more receive directions 182″. The UE 104 may also transmit a beamformed signal to the base station 180 in one or more transmit directions. The base station 180 may receive a beamformed signal from the UE 104 in one or more receive directions. The base station 180 / UE 104 may perform beam training to determine the best receive direction and transmit direction for each of the base station 180 / UE 104. The transmit direction and receive direction for the base station 180 may be the same or different. The transmit direction and receive direction for the UE 104 may be the same or different. Although this example is described for the base station 180 and the UE 104, these aspects may similarly apply between a first device and a second device (e.g., a first UE and a second UE) for sidelink communication.

[0043] The EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may communicate with a Home Subscriber Server (HSS) 174. The MME 162 is a control node that handles signaling between the UE 104 and the EPC 160. In general, the MME 162 handles bearer and connection management. All user Internet Protocol (IP) packets are forwarded through the Serving Gateway 166, which is itself connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176. The IP services 176 may include Internet, Intranet, IP Multimedia Subsystem (IMS), PS streaming services, and / or other IP services. The BM-SC 170 may provide functionality for MBMS user service provisioning and delivery. The BM-SC 170 may act as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services in the Public Land Mobile Network (PLMN), and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to deliver MBMS traffic to base stations 102 that belong to a Multicast Broadcast Single Frequency Network (MBSFN) area that broadcasts a particular service, and may be responsible for session management (start / stop) and collection of eMBMS-related charging information.

[0044] The core network 190 may include an access and mobility management function (AMF) 192, other AMFs 193, a session management function (SMF) 194, and a user plane function (UPF) 195. The AMF 192 may communicate with an integrated data management (UDM) 196. The AMF 192 is a control node that handles signaling between the UE 104 and the core network 190. In general, the AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are forwarded through the UPF 195. The UPF 195 provides IP address allocation for the UE as well as other functions. The UPF 195 is connected to IP services 197. The IP services 197 may include the Internet, intranets, IP multimedia subsystem (IMS), packet switched (PS) streaming (PSS) services, and / or other IP services.

[0045] A base station may include and / or be referred to as a gNB, Node B, eNB, access point, base transceiver station, radio base station, radio transceiver, transceiver function, basic service set (BSS), extended service set (ESS), transmit reception point (TRP), or some other suitable terminology. The base station 102 provides an access point to the EPC 160 or core network 190 for the UE 104. Examples of the UE 104 include a mobile phone, a smartphone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small cooking appliance, a health management device, an implant, a sensor / actuator, a display, or any other similar function device. Some of the UEs 104 may be referred to as IoT devices (e.g., parking meters, gas pumps, toasters, vehicles, heart monitors, etc.). The UE 104 may also be referred to as a station, mobile station, subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or any other suitable terminology.

[0046] FIG. 2 includes diagrams 200 and 210 illustrating example aspects of slot structures that may be used for sidelink communications (e.g., between UE 104, RSU 107, etc.). In some examples, the slot structures may be in a 5G / NR frame structure. In other examples, the slot structures may be in an LTE frame structure. Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar domains, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies. The example slot structure of FIG. 2 is only an example, and other sidelink communications may have different frame structures and / or different channels for sidelink communications. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms). Each subframe may include one or more time slots. A subframe may also include minislots, which may include 7 symbols, 4 symbols, or 2 symbols. Each slot may include 14 or 12 symbols depending on whether the cyclic prefix (CP) is normal or extended. In normal CP, each slot may contain 14 symbols, and in extended CP, each slot may contain 12 symbols. The symbols may be CP Orthogonal Frequency Division Multiplexing (OFDM) (CP-OFDM) symbols. The symbols may be CP-OFDM symbols (high throughput scenarios) or Discrete Fourier Transform (DFT) Spread OFDM (DFT-s-OFDM) symbols (also called Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols) (limited to single stream transmission in power limited scenarios). The number of slots in a subframe is based on the CP and numerology. The numerology defines the subcarrier spacing (SCS), which essentially defines the symbol length / time length, which is equal to 1 / SCS.

[0047] [Table 1]

[0048] For normal CP (14 symbols / slot), the different numerologies μ “0” to μ “4” allow 1, 2, 4, 8, and 16 slots per subframe, respectively. For extended CP, numerology 2 allows 4 slots per subframe. Thus, for normal CP and numerology μ, 14 symbols / slot and 2 μ There are slots / subframes. The subcarrier spacing is 2 μ * may be equal to 15 kHz, where μ is the numerology "0" to 4. Thus, numerology μ=0 has a subcarrier spacing of 15 kHz, and numerology μ=4 has a subcarrier spacing of 240 kHz. The symbol length / time length is inversely proportional to the subcarrier spacing. Figure 2 provides an example of a normal CP of 14 symbols per slot. Within a set of frames, there may be one or more different bandwidth parts (BWPs) that are frequency division multiplexed. Each BWP may have a specific numerology and CP (normal or extended).

[0049] FIG. 200 illustrates a single resource block of a single slot transmission, which may correspond, for example, to a transmission time interval (TTI) of 0.5 ms. The physical sidelink control channel may be configured to occupy multiple physical resource blocks (PRBs), for example, 10, 12, 15, 20, or 25 PRBs. The PSCCH may be limited to a single subchannel. The PSCCH duration may be configured to be, for example, 2 or 3 symbols. The subchannel may include, for example, 10, 15, 20, 25, 50, 75, or 100 PRBs. Resources for sidelink transmission may be selected from a resource pool that includes one or more subchannels. As a non-limiting example, the resource pool may include 1 to 27 subchannels. The PSCCH size may be established for a resource pool, for example, as 10-100% of one subchannel for a duration of 2 or 3 symbols. Diagram 210 of Figure 2 shows an example in which the PSCCH occupies approximately 50% of the subchannel as an example to illustrate the concept of the PSCCH occupying a portion of the subchannel. A physical sidelink shared channel (PSSCH) occupies at least one subchannel. The PSCCH may include a first portion of sidelink control information (SCI), and the PSSCH may include a second portion of the SCI in some examples.

[0050] A resource grid may be used to represent the frame structure. Each time slot may include a resource block (RB) (also referred to as a physical RB (PRB)) spanning 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme. As shown in FIG. 2, some of the REs may include control information in the PSCCH and some REs may include a demodulation RS (DMRS). At least one symbol may be used for feedback. FIG. 2 shows an example where there are adjacent gap symbols along with two symbols for the physical sidelink feedback channel (PSFCH). Symbols before and / or after the feedback may be used for transition between receiving data and transmitting feedback. The gap allows a device to switch from operating as a transmitting device, for example, to prepare to operate as a receiving device in the next slot. As shown, data may be transmitted in the remaining REs. The data may comprise a data message as described herein. The location of any of the data, DMRS, SCI, feedback, gap symbols, and / or LBT symbols may differ from the example shown in Figure 2. In some aspects, multiple slots may be aggregated together.

[0051] FIG. 3 is a block diagram 300 of a first wireless communication device 310 communicating with a second wireless communication device 350. The communication may be based on a sidelink or an access link. In some examples, the wireless communication devices 310, 350 may communicate based on V2X communication or other D2D communication. In other aspects, the wireless communication devices 310, 350 may communicate over an access link based on uplink and downlink transmissions. The communication may be based on a sidelink using a PC5 interface (e.g., between two UEs). The communication may be based on an access link using a Uu interface (e.g., between a base station and a UE). The wireless communication devices 310, 350 may include a UE, an RSU, a base station, etc. In some implementations, the first wireless communication device 310 may correspond to a base station and the second wireless communication device 350 may correspond to a UE.

[0052] 3, the first wireless communication device 310 includes a transmit processor (TX processor 316), a transceiver 318 including a transmitter 318a and a receiver 318b, an antenna 320, a receive processor (RX processor 370), a channel estimator 374, a controller / processor 375, and a memory 376. The example second wireless communication device 350 includes an antenna 352, a transceiver 354 including a transmitter 354a and a receiver 354b, a RX processor 356, a channel estimator 358, a controller / processor 359, a memory 360, and a TX processor 368. In other examples, the first wireless communication device 310 and / or the second wireless communication device 350 may include additional or alternative components.

[0053] The packets may be provided to a controller / processor 375 that implements layer 3 and layer 2 functions. Layer 3 includes the Radio Resource Control (RRC) layer, and layer 2 includes the Packet Data Convergence Protocol (PDCP) layer, the Radio Link Control (RLC) layer, and the Medium Access Control (MAC) layer.

[0054] The TX processor 316 and the RX processor 370 implement layer "1" functions related to various signal processing functions. Layer 1, which includes the physical (PHY) layer, may include error detection on transport channels, forward error correction (FEC) coding / decoding of transport channels, interleaving, rate matching, mapping to physical channels, modulation / demodulation of physical channels, and MIMO antenna processing. The TX processor 316 processes mapping to signal constellations based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time-domain OFDM symbol stream. The OFDM stream is spatially precoded to generate multiple spatial streams. Channel estimates from a channel estimator 374 may be used for spatial processing as well as to determine the coding and modulation scheme. The channel estimates may be derived from a reference signal and / or channel condition feedback transmitted by the second wireless communication device 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318a. Each transmitter 318a may modulate a radio frequency (RF) carrier with the respective spatial stream for transmission.

[0055] In the second wireless communication device 350, each receiver 354b receives a signal through a respective antenna 352. Each receiver 354b recovers the information modulated onto an RF carrier and provides the information to the RX processor 356. The TX processor 368 and the RX processor 356 implement layer "1" functions related to various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the second wireless communication device 350. If multiple spatial streams are destined for the second wireless communication device 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then converts the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation point transmitted by the first wireless communication device 310. These soft decisions may be based on channel estimates calculated by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted by the first wireless communication device 310 on the physical channel. The data and control signals are then provided to a controller / processor 359, which implements layer 3 and layer 2 functions.

[0056] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. The controller / processor 359 may provide demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing. The controller / processor 359 is also responsible for error detection using an acknowledgement (ACK) and / or negative acknowledgement (NACK) protocol to support hybrid automatic repeat request (HARQ) operations.

[0057] Similar to the functionality described with respect to transmission by the first wireless communications device 310, the controller / processor 359 provides RRC layer functionality related to system information (e.g., MIBs, SIBs) acquisition, RRC connection, and measurement reporting; PDCP layer functionality related to header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality related to transfer of higher layer PDUs, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality related to mapping between logical channels and transport channels, multiplexing of MAC SDUs onto the TB, demultiplexing of MAC SDUs from the TB, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0058] Channel estimates derived by the channel estimator 358 from a reference signal or feedback transmitted by the first wireless communication device 310 may be used by the TX processor 368 to select an appropriate coding and modulation scheme and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354a. Each transmitter 354a may modulate an RF carrier with a respective spatial stream for transmission.

[0059] The transmission is processed at the first wireless communication device 310 in a manner similar to that described with respect to the receiver functions at the second wireless communication device 350. Each receiver 318b receives signals through a respective antenna 320. Each receiver 318b recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

[0060] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. The controller / processor 375 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing. The controller / processor 375 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0061] At least one of the TX processor 368 or TX processor 316, the RX processor 356 or RX processor 370, and the controller / processor 359 or controller / processor 375 may be configured to perform aspects associated with the SL component 198 of FIG.

[0062] 4 illustrates an example 400 of sidelink communication between devices as presented herein. The communication may be based on a slot structure including the aspects described with respect to FIG. 2 or another sidelink structure. For example, the first UE 402 may transmit a sidelink transmission 410 including, for example, a control channel (e.g., PSCCH) and / or a corresponding data channel (e.g., PSSCH), which may be received by, for example, the second UE 406 and / or the third UE 408. The sidelink transmission 410 may be received directly from the first UE 402, for example, without transmission through a base station.

[0063] The first UE 402, the second UE 406, and / or the third UE 408 may each be capable of operating as a transmitting device in addition to operating as a receiving device. Thus, the second UE 406 is shown to transmit a sidelink transmission 412 that is received by the first UE 402. One or more of the sidelink transmissions 410, 412 may be broadcast or multicast to nearby devices. For example, the first UE 402 may transmit a communication intended for reception by other UEs within the range 401 of the first UE 402. In other examples, one or more of the sidelink transmissions 410, 412 may be groupcast to nearby devices that are members of a group. In other examples, one or more of the sidelink transmissions 410, 412 may be unicast from one UE to another UE.

[0064] A sidelink transmission may provide sidelink control information (SCI) that includes information to facilitate decoding a corresponding data channel. For example, a transmitting device (which may be referred to as an “originating device,” “transmitting UE,” or “originating UE”) may transmit an SCI that includes information that a receiving device (which may be referred to as a “target device,” “receiving UE,” or “target UE”) may use to avoid interference. For example, the SCI may indicate reserved time resources and / or reserved frequency resources occupied by the data transmission and may be indicated in a control message from the transmitting device. The number of TTIs as well as the number of RBs occupied by the data transmission may be indicated in a control message from the first UE 402. In some examples, the SCI may be used by the receiving device to avoid interference by refraining from transmitting on resources occupied during the data transmission.

[0065] One or more of the first UE 402, the second UE 406, and / or the third UE 408 may include an SL component similar to the SL component 198 described in connection with FIG.

[0066] Sidelink communication allows a first UE to communicate directly with another UE. For example, the first UE and the other UE may communicate without routing the communication through a base station. Sidelink may be beneficial for vehicle-based communications (e.g., V2V, V2I, V2N, V2P, C-V2X, etc.), which allows a vehicular UE to communicate directly with another UE or a pedestrian UE. When dealing with V2X communications, power consumption by a vehicular UE may not be an issue.

[0067] However, it may be beneficial for some devices to implement a power saving mode. Two examples of power saving modes include partial sensing or random selection and discontinuous reception (DRX). In either DRX or partial sensing, the UE may skip sensing of resource reservations for some time. For example, the skipped sensing may save battery power at the UE.

[0068] Sidelink communication may be based on different types or modes of resource allocation mechanisms. In a first resource allocation mode (which may be referred to herein as “Mode 1”), a centralized resource allocation may be performed by a network entity. For example, referring to the example of FIG. 1, the base station 102 / 180 may determine resources for sidelink communication and may allocate resources to different UEs to use for sidelink transmission. In the first mode, the UE receives an allocation of sidelink resources from the base station 102 / 180. In a second resource allocation mode (which may be referred to herein as “Mode 2”), a distributed resource allocation may be performed. In Mode 2, each UE may autonomously determine resources to use for sidelink transmission. To coordinate the selection of sidelink resources by individual UEs, each UE may use sensing techniques to monitor resource reservations by other sidelink UEs and may select resources for sidelink transmission from the unreserved resources. A device communicating based on sidelink may determine one or more radio resources in the time and frequency domains used by other devices to select transmission resources that avoid collisions with other devices. Sidelink transmission and / or resource reservation may be periodic or aperiodic, and the UE may reserve resources for transmission in the current slot and up to two future slots.

[0069] Thus, in a second mode (e.g., mode 2), an individual UE may autonomously select resources for sidelink transmissions without a central entity, such as a base station, indicating resources for the device. A first UE may reserve the selected resources to inform other UEs about the resources the first UE intends to use for sidelink transmissions.

[0070] In some examples, resource selection for sidelink communication may be based on a sensing-based mechanism. For example, before selecting a resource for data transmission, the UE may first determine whether the resource has been reserved by another UE.

[0071] For example, as part of the sensing mechanism for resource allocation mode 2, the UE may determine (e.g., sense) whether the selected sidelink resource has been reserved by another UE before selecting a sidelink resource for data transmission. If the UE determines that the sidelink resource is not reserved by another UE, the UE may use the selected sidelink resource for transmitting data, e.g., in a PSSCH transmission. The UE may estimate or determine which radio resources (e.g., sidelink resources) may be used and / or reserved by others by detecting and decoding sidelink control information (SCI) transmitted by other UEs. The UE may use a sensing-based resource selection algorithm to estimate or determine which radio resources are used and / or reserved by others. The UE may receive an SCI from another UE that includes reservation information based on a resource reservation field included in the SCI. The UE may continuously monitor (e.g., sense) and decode the SCI from the peer UE. The SCI may include reservation information, e.g., indicating the slots and RBs that a particular UE has selected for future transmissions. The UE may exclude resources used and / or reserved by other UEs from a set of resource candidates for sidelink transmission by the UE, and the UE may select / reserve resources for sidelink transmission from the unused resources, thus forming a set of resource candidates. The UE may continuously perform sensing on the SCI with resource reservation to maintain a set of resource candidates from which the UE may select one or more resources for sidelink transmission. Once the UE selects a resource candidate, the UE may transmit an SCI indicating its own reservation of resources for sidelink transmission. The number of resources (e.g., subchannels per subframe) reserved by the UE may depend on the size of the data transmitted by the UE. Although an example is described for a UE receiving a reservation from another UE, reservations may also be received from RSUs or other devices communicating based on the sidelink.

[0072] FIG. 5 is an example 500 of time and frequency resources illustrating reservations for sidelink transmissions as presented herein. The resources may be included in a sidelink resource pool, for example. The resource allocation for each UE may be in units of one or more subchannels (e.g., subchannels SC1 to SC4) in the frequency domain, or based on one slot (e.g., slots "1" to 8) in the time domain. The UE may also use resources in a current slot to perform an initial transmission and reserve resources in a future slot for retransmission. In the illustrated example of FIG. 5, two different future slots are reserved by UE1 and UE2 for retransmission. The resource reservation may be limited to a predefined slot and subchannel interval, such as 8 time slots by 4 subchannel intervals as shown in the example 500, resulting in a total of 32 available resource blocks. This interval may also be referred to as a resource selection interval.

[0073] A first UE ("UE1") may reserve a subchannel (e.g., SC1) in a current slot (e.g., slot 1) for its initial data transmission 502 and may reserve additional future slots in the interval for data transmissions (e.g., first data retransmission 504 and second data retransmission 506). For example, the first UE may reserve subchannels SC3 in slot 3 and SC2 in slot 4 for future retransmissions as shown by FIG. 5. The first UE then transmits information to other UEs regarding which resources are being used and / or reserved by the first UE. The first UE may do so by including the reservation information in a reserved resource field of an SCI, e.g., a first stage SCI.

[0074] Figure 5 shows that a second UE ("UE2") reserves resources in sub-channels SC3 and SC4 in slot "1" for a current data transmission 508, reserves a first data retransmission 510 in slot 4 using sub-channels SC3 and SC4, and reserves a second data retransmission 512 in slot 7 using sub-channels SC"1" and SC2, as shown in Figure 5. Similarly, the second UE may transmit resource usage and reservation information to other UEs, such as using a reserved resources field in the SCI.

[0075] The third UE may consider resources reserved by other UEs in the resource selection interval to select resources for transmitting its data. The third UE may first decode the SCI in a period to identify which resources are available (e.g., resource candidates). For example, the third UE may exclude resources reserved by UE1 and UE2 and select other available subchannels and time slots from the resource candidates for its transmission and retransmission, which may be based on the number of adjacent subchannels into which the data (e.g., packet) to be transmitted can fit.

[0076] Although FIG. 5 shows resources being reserved for an initial transmission and two retransmissions, the reservation may be for the initial transmission and a single transmission, or just for the initial transmission.

[0077] The UE may determine an associated signal measurement (e.g., RSRP) for each resource reservation received by another UE. The UE may consider resources reserved in such transmissions for which the UE measures an RSRP below a threshold as usable by the UE. The UE may perform signal / channel measurements on sidelink resources reserved and / or used by other UEs, such as by measuring the RSRP of a message reserving sidelink resources (e.g., SCI). Based at least in part on the signal / channel measurements, the UE may consider using / reusing sidelink resources reserved by other UEs. For example, if the measured RSRP meets or exceeds a threshold, the UE may exclude the reserved resources from the resource candidate set, and if the measured RSRP of the message reserving the resources is below the threshold, the UE may consider the reserved resources as available. The UE may include the resources in the resource candidate set and may use / reuse such reserved resources when the message reserving the resources has an RSRP below the threshold, since a low RSRP indicates that other UEs are far away and that resource reuse is less likely to cause interference to the UE. A higher RSRP indicates that a transmitting UE that has reserved resources may be closer to the UE and may experience higher levels of interference if the UE selects the same resource.

[0078] For example, the UE may determine a set of resource candidates (e.g., by monitoring SCIs from other UEs and removing resources from a set of resource candidates reserved by other UEs in signals where the UE measures an RSRP above a threshold). The UE may also select N resources for transmission and / or retransmission of the TB. As an example, the UE may randomly select N resources from a previously determined set of resource candidates. For each transmission, the UE may reserve future time and frequency resources for the initial transmission and up to two retransmissions. The UE may reserve resources by transmitting an SCI indicating resource reservation. For example, in the example of FIG. 5, the second UE may transmit an SCI reserving resources for the current data transmission 508, the first data retransmission 510, and the second data retransmission 512.

[0079] There may be a timeline for sensing-based resource selection. For example, the UE may sense and decode SCI received from other UEs during a sensing interval, e.g., a certain length of time before resource selection. Based on the sensing history during the sensing interval, the UE may be able to maintain a set of available resource candidates by excluding resources reserved by other UEs from the set of resource candidates. The UE may select a resource from its set of available resource candidates and transmit an SCI reserving the selected resource for a sidelink transmission (e.g., PSSCH transmission) by the UE. There may be a time gap between the UE's selection of a resource and the UE's transmission of the SCI reserving the resource.

[0080] In resource allocation mode 2, the higher layer may request the UE 104, including the SL component 198, to determine a subset of resources from which the higher layer may select resources for PSSCH / PSCCH transmission. FIG. 6 illustrates an example timing diagram 600 for a UE that may be triggered to select resources for sidelink transmission in response to a resource selection trigger 650. The timing diagram illustrates the timing of sensing of resource reservations from other UEs, such as the resource reservations described in connection with FIG. 5. As an example, the resource selection trigger 650 may include having data for transmission. Although FIG. 6 is described with respect to a UE, resource selection may also be applied by other sidelink devices. In response to the resource selection trigger 650, the UE may consider signals received within a sensing interval 602 of length T_0 and determine information (e.g., SCI with resource reservation) received within the sensing interval 602. For example, the UE may determine which resources were used or reserved by other UEs during the sensing interval 602. The UE may expect that previously used resources may also be used by other UEs in the future. The signal received in the sensing interval may include an SCI indicating resource reservation of resources in the resource selection interval 604 following the resource selection trigger 650. Based on past usage of the resources and / or reservation of the resources (e.g., "sensing" the resources), the UE may determine which resources are scheduled for use and / or which resources are not scheduled for use. For example, based on sensing of the resources during the sensing interval 602, the UE may determine that the first resource 606 and the second resource 608 may be reserved during slots associated with the resource selection trigger 650 and / or during future slots. The UE may exclude resource candidates reserved by other UEs from a candidate set of resources when selecting sidelink transmission resources. In some examples, the UE may exclude resource candidates that are reserved by another UE and meet one or more conditions, such as a reservation signal that meets an RSRP threshold.The UE may select a resource 610 for transmission.

[0081] In some wireless communication systems, a receiving UE may perform sensing and inform a transmitting UE (along with other UEs) about available resources for transmission based on the sensing results. For example, a receiving UE may be a smartphone with higher processing power and battery capacity than a transmitting UE, which may be a smartwatch with limited battery capacity and limited processing power. Therefore, it may be more efficient to have a receiving UE with a larger battery capacity and higher processing power to perform sensing for the transmitting UE.

[0082] In some cases, multiple UEs may transmit simultaneously and may not receive overlapping communications (e.g., SCIs indicating resource reservations) from each other and / or from the base station. Such UEs may miss or be unaware of transmissions and sidelink reservations by other UEs. Thus, two UEs may reserve the same resource blocks for future sidelink transmissions, which may result in resource collisions. Resource collisions occur in sidelink transmissions that may at least partially overlap in time and at least partially overlap in frequency.

[0083] To reduce or avoid resource collisions in such cases and to improve sidelink communications between UEs, UEs may coordinate with each other by generating and sharing inter-UE coordination information with other UEs. Figure 7A is a diagram 700 illustrating an exchange of inter-UE coordination information, where a first UE ("UE-A") 712 transmits inter-UE coordination information 716 to a second UE ("UE-B") 714. In some aspects, the transmission of inter-UE coordination information may include a resource reservation transfer by UE-A.

[0084] The UE-to-UE coordination information 716 may include information based on UE sensing information (e.g., resource reservations of other UEs sensed by the UE 712 (e.g., UE-A)), UE-to-UE coordination information from another UE, resources that are bad, undesirable, or unpreferred for the UE-A 712 (e.g., resources that experience high interference), resources that are preferred for the UE-A 712 or are preferred over other resources, etc.

[0085] The inter-UE coordination information 716 may indicate resource candidates for sidelink transmission or preferred resources for transmission by UE-B 714. In some aspects, the indication of preferred resources for UE-B transmission may be referred to as "Type A" inter-UE coordination information. UE-A 712 may use the inter-UE coordination information 716 to inform UE-B 714 which subchannels and slots may be used to communicate with UE-A 712 and / or which subchannels and slots may not be used because they are occupied or reserved by UE-A 712 and / or other UEs. UE-A may indicate a set of resources that may be more suitable for UE-B transmission based on UE-A's evaluation. The resource candidates may indicate a group of resources that UE-B 714 (e.g., UE-B) may select for sidelink transmission 718. As shown, the sidelink transmission 718 may be for UE-A 712 or may be for one or more different UEs, e.g., UE-C 719. In some aspects, UE-A may be a possible receiver of UE-B's transmissions and the inter-UE coordination information may enable Mode 2 resource allocation based on resource availability from the perspective of the possible receivers, which may address reception issues for hidden nodes. In some aspects, the inter-UE coordination information 716 may indicate resources for sidelink transmissions, e.g., specific resources on which UE-B 714 will transmit sidelink transmission 718, rather than candidate resources that UE-B 714 may select.

[0086] In some aspects, the inter-UE coordination information 716 may indicate a set of resources that may be non-preferred for UE-B transmissions, such as resources that may not be available to UE-B for transmitting sidelink transmissions based on UE-A's evaluation. In some aspects, the indication of non-preferred resources for UE-B transmissions may be referred to as "Type B" inter-UE coordination information.

[0087] In some aspects, the inter-UE cooperation information 716 may indicate half-duplex contention. For example, the inter-UE cooperation information 716 may indicate a collision in time and / or frequency for two transmitting UEs that cannot receive each other's respective transmissions in half-duplex mode. In some aspects, the inter-UE cooperation information 716 may indicate a resource collision (e.g., reserved resources) in time and / or frequency. In some aspects, an indication of a collision / contention in resources may be referred to as "Type C" inter-UE cooperation information.

[0088] Based at least in part on the inter-UE coordination information 716 from UE-A 712, UE-B 704 may make better decisions about which resources to use and / or reserve for its sidelink transmissions 718 to avoid resource collisions. UE-A 712 may share the inter-UE coordination information 716 with multiple UEs, and UE-B 714 may receive the inter-UE coordination information 716 from multiple UEs. The inter-UE coordination information 716 may be transmitted in any of a variety of manners.

[0089] The UE-A 712 may transmit UE-to-UE coordination information 716 in the PSFCH, for example, indicating an indication of resource collision or half-duplex contention. The UE-A 712 may transmit UE-to-UE coordination information 716 in the SCI. For example, the UE-A 712 may transmit shared sensing information, resource candidate information for sidelink transmission, or specific resources for sidelink transmission in SCI-2 transmitted in the PSSCH. For example, a first part of the SCI (e.g., SCI-1) may be transmitted in the PSCCH and a second part of the SCI (e.g., SCI-2) may be transmitted in the PSSCH. The UE-A 712 may transmit UE-to-UE coordination information 716 in the MAC-CE, for example, on the PSSCH. The UE-A 712 may transmit UE-to-UE coordination information 716 in a new physical channel (e.g., different from the PSCCH, PSSCH, PSFCH, etc.). For example, the UE-A 712 may transmit the inter-UE coordination information 716 in a physical channel configured for or dedicated to inter-UE configuration information. The UE-A 712 may transmit the inter-UE coordination information 716 in RRC signaling.

[0090] In some aspects, UE-A 712 may periodically transmit UE-to-UE coordination information 716. In some aspects, UE-A 712 may transmit aperiodic UE-to-UE coordination information 716 in response to a trigger. Among other examples, the trigger may be based on the occurrence of an event, such as the occurrence / detection of a resource collision, the occurrence / detection of a half-duplex contention, etc. For example, if UE-A 712 detects a resource collision, UE-A 712 may respond by transmitting UE-to-UE coordination information 716.

[0091] UE-B 714 may utilize inter-UE coordination information 716 in various ways.

[0092] If the inter-UE coordination information 716 includes information about preferred resources for UE-B 714 transmission and / or non-preferred resources for UE-B 714 transmission, according to a first option, UE-B 704 may select resources to be used for its sidelink transmission resource selection or the resource re-selection may be based on both UE-B sensing results (if available) and the received inter-UE coordination information 716. In a second option, UE-B 714 may select resources to be used for its sidelink transmission resource selection or the resource re-selection may be based on the received inter-UE coordination information 716 and not on sensing. In a third option, UE-B 714 may select resources to be used for its sidelink transmission resource selection or the resource re-selection may be based on the received inter-UE coordination information 716 (which may enable UE-B to use or not use sensing in combination with inter-UE coordination information 716).

[0093] FIG. 7B is a diagram 750 illustrating an exchange of UE-to-UE coordination information that a UE 702 may provide to multiple UEs. As shown in FIG. 7B, the UE 702 may be more capable of performing sensing compared to the UE 704, UE 706, or UE 708. For example, the UE 702, which may be a receiving UE receiving a transmission from the UE 704, UE 706, or UE 708, may have higher processing capability and / or a larger battery capacity than the UE 704, UE 706, or UE 708. Thus, it may be more efficient for the UE 702 with the larger battery capacity / higher processing capability to perform sensing and transmit (e.g., groupcast) the resource availability information 722 to the UE 704, UE 706, and UE 708. Moreover, the UE 702 may have information about the UE 704, UE 706, and UE 708 based on measuring the RSRP of signals on the incoming link. For example, the UE 702 may be able to measure RSRP on a link between the UE 702 and the UE 704, a link between the UE 702 and the UE 706, and a link between the UE 702 and the UE 708. By measuring the different links, the UE 702 may be able to better identify available resources.

[0094] In some circumstances, based on the sensing, the receiving UE 702 may identify a first set of available resources for transmission 724 from the UE 704 to the UE 702 that may be less than a threshold amount of resources (e.g., determined to be inappropriately small by comparing the size of the available resources to an availability threshold). Aspects provided herein enable the receiving UE to re-evaluate a set of available resources that may be suitable for sidelink transmission by adjusting the measurement threshold, such that the amount of available resources identified in the inter-UE coordination information is more consistent.

[0095] FIG. 8 is an example diagram 800 illustrating communication flows between UEs including transmission of UE-UE coordination information according to aspects presented herein. Both UE 802 and UE 804 of FIG. 8 may be operating in sidelink resource allocation mode 2. UE 802 of FIG. 8 may correspond to UE-A 712 of FIG. 7A and / or UE 702 of FIG. 7B, and UE 804 of FIG. 8 may correspond to UE-B 714 of FIG. 7A and / or UE 704 of FIG. 7B. In some aspects, UE 802 may have higher processing capabilities and / or larger battery capacity than UE 804. At 810, UE 802 may perform sensing (e.g., as described in connection with FIG. 5 and FIG. 6) to identify resources available for UE 804. In some aspects, UE 802 may generate a resource availability report 812 that UE 802 transmits to other UEs. A resource availability report may refer to a set of information representative of the availability of each of one or more resources. As an example, each "0" represented in the resource availability report 812 may indicate that the resource mapped to the "0" is unavailable to the UE 804, and each "1" represented in the resource availability report 812 may indicate that the resource mapped to the "1" is available to the UE 804. Although an example is shown of a single UE receiving the availability report 812, which may be done as a unicast, in some aspects the UE 802 may similarly broadcast or groupcast the availability report 812 to multiple UEs. As part of the sensing, at 810 the UE 802 may perform one or more sensing measurements, such as SIR measurements, RSRP measurements, RSRQ measurements, etc. The UE 802 may compare the results of the sensing measurements for each of the resources to a measurement threshold. In some aspects, if the result of the sensing measurement for a resource is less than the measurement threshold, the UE 802 may determine that the resource is available to the UE 804. If the result of the sensing measurement for the resource is not below the measurement threshold, the UE 802 may determine that the resource is unavailable to the UE 804.In some aspects, if the result of the sensing measurement for a resource exceeds a measurement threshold, the UE 802 may determine that the resource is available to the UE 804. If the result of the sensing measurement for a resource does not exceed the measurement threshold, the UE 802 may determine that the resource is unavailable to the UE 804.

[0096] In some aspects, the measurement threshold may be associated with (e.g., may be a function of) one or more priorities of packets associated with an associated transmission (e.g., transmission 824) of the UE 804. In some aspects, the measurement threshold may be associated with (e.g., may be a function of) one or more modulation and coding schemes (MCSs) associated with the UE 804.

[0097] In some aspects, the UE 802 may determine that the identified available resources identified at 810 (such as resources shown as available in the resource availability report 812) may be inappropriately small for the UE 804. For example, the UE 802 may determine that the identified available resources identified at 810 may be inappropriately small for the UE 804 by comparing the size of the available resources to an availability threshold. In some aspects, the size of the available resources and the availability threshold may be defined in terms of a total number of resources. In some aspects, the size of the available resources and the availability threshold may be defined in terms of a percentage compared to the resources being sensed. For example, the availability threshold may be 50%, and the UE 802 may determine that the size of the available resources is inappropriately small for the UE 804 if the available resources are less than 50% of the total amount of resources in the resource selection interval. Upon determining that the size of the available resources is inappropriately small, at 814, the UE 802 may adjust a measurement threshold and re-identify the available resources based on the adjusted measurement threshold. For example, the UE 802 may lower the SIR threshold by a number of decibels (dB) and then re-identify available resources based on the new SIR threshold by comparing the SIR associated with the resource to the new SIR threshold. For each resource, if the SIR associated with the resource exceeds the SIR threshold, the resource may be determined by the UE 802 to be available to the UE 804. In some aspects, the UE 802 may continue to adjust the measurement threshold and re-identify available resources based on the adjusted measurement threshold until a maximum / minimum allowed measurement threshold is reached or until the amount of available resources reaches an availability threshold. As an example, the UE 802 may generate a resource availability report 816. In some aspects, each "0" in the resource availability report 816 may indicate that the resource mapped to the "0" is unavailable to the UE 804, and each "1" in the resource availability report 816 may indicate that the resource mapped to the "1" is available to the UE 804.As shown in FIG. 8, the size of the resource shown as available in the resource availability report 816 may exceed the availability threshold of 50% because more than 50% of the resource is available.

[0098] In some aspects, the UE 802 may sort each of the available resources in descending order, starting with the resource associated with the measurement value furthest from the measurement threshold. For example, the UE may sort all resources having a SIR higher than the SIR threshold in descending order of SIR level.

[0099] In some aspects, the UE 802 may provide a resource availability report 818 to the UE 804. In some aspects, the resource availability report 818 may include the resource availability report 816. In some aspects, the resource availability report 818 may include a report sorting the top X% available resources in descending order, starting with the resource associated with the measurement value furthest from the measurement threshold. In some aspects, X may be defined based on the availability threshold or a different threshold. The UE may adjust the measurement threshold until a report is reported that X% of available resources can be identified or until the maximum / minimum allowed measurement threshold is reached.

[0100] In some aspects, the UE 802 may also schedule one or more resources for the UE 804 by transmitting a resource reservation 820 to the one or more UEs. In some aspects, the UE 802 may not schedule one or more resources for the UE 804. In some aspects, upon receiving the resource availability report 818, the UE 804 may select one or more resources indicated as available in the resource availability report 818 for a transmission 824 to the UE 802. In some aspects, as shown at 822 in FIG. 8, the UE 804 may select one or more resources indicated as available in the resource availability report 818 (denoted as “S”). The UE 804 may use the one or more selected resources to transmit a transmission 824 to the UE 802.

[0101] 9 is a flowchart 900 of a method of wireless communication. The method may be performed by a UE (e.g., UE 104, UE 702, UE 802, device 1302). The method may enable a receiving UE to re-identify a first set of available resources that may be suitable for transmission of the transmitting UE by adjusting a measurement threshold, resulting in a more efficient sidelink transmission.

[0102] At 902, the UE may perform sensing on one or more SL resources to identify a first set of available resources. For example, at 810, the UE 802 may perform sensing on one or more SL resources to identify a first set of available resources. In some aspects, 902 may be performed by the sensing component 1342 of FIG. 13.

[0103] At 904, the UE may adjust the first measurement threshold to the second measurement threshold based on the size of the first set of available resources being less than the availability threshold. For example, at 814, the UE 802 may adjust the first measurement threshold to the second measurement threshold based on the size of the first set of available resources being less than the availability threshold. In some aspects, 904 may be performed by the availability component 1344 of FIG. 13. For example, the size may be defined based on a percentage for one or more SL resources. As an example, if 50% of the resources are available in one or more SL resources, the size of the first set of available resources may be 50%.

[0104] At 906, the UE may transmit a sidelink message indicating a second set of available resources based on the second measurement threshold. For example, the UE 802 may transmit a sidelink message (e.g., resource availability report 818) indicating a second set of available resources that are available based on the second measurement threshold. In some aspects, 906 may be performed by the SL component 1346 of FIG. 13.

[0105] 10 is a flowchart 1000 of a method of wireless communication. The method may be performed by a UE (e.g., UE 104, UE 702, UE 802, device 1302). The method may enable a receiving UE to re-identify a first set of available resources that may be suitable for transmission of the transmitting UE by adjusting a measurement threshold, resulting in a more efficient sidelink transmission.

[0106] At 1002, the UE may perform sensing on one or more SL resources to identify a first set of available resources. For example, at 810, the UE 802 may perform sensing on one or more SL resources to identify a first set of available resources. In some aspects, 1002 may be performed by the sensing component 1342 of FIG. 13.

[0107] At 1004, the UE may adjust the first measurement threshold to the second measurement threshold based on the size of the first set of available resources being less than the availability threshold. For example, at 814, the UE 802 may adjust the first measurement threshold to the second measurement threshold based on the size of the first set of available resources being less than the availability threshold. In some aspects, 1004 may be performed by the availability component 1344 of FIG. 13. In some aspects, the availability threshold may include a percentage of available resources from one or more SL resources. For example, the size may be defined based on a percentage for one or more SL resources. As an example, if 50% of the resources are available in one or more SL resources, the size of the first set of available resources may be 50%. In some aspects, the availability threshold may include a size of available resources from one or more SL resources. In some aspects, the first measurement threshold is a first SIR ratio value and the second measurement threshold is a second SIR ratio value. As an example, the first SIR ratio value may be lower or higher than the second SIR ratio value. In some aspects, the first SIR ratio value or the second SIR ratio value may be based on one or more functions of a priority associated with the sidelink communication associated with the second UE based on the sensing, or an MCS associated with the second UE. In some aspects, the first measurement threshold may be a first RSRQ threshold and the second measurement threshold may be a second RSRQ threshold. The first RSRQ threshold may be lower or higher than the second RSRQ threshold. In some aspects, the second measurement threshold may be based on one or more of a packet priority associated with the sidelink communication associated with the second UE, an MCS associated with the second UE, a cast type associated with the second UE, a remaining packet delay budget associated with the sidelink communication associated with the second UE, a communication range specification associated with the second UE, a HARQ ACK utilization status associated with the sidelink communication associated with the second UE, a channel busy ratio (CBR), or a distance between the UE and the second UE.

[0108] At 1006, the UE may transmit a sidelink message indicating a second set of available resources based on the second measurement threshold. For example, the UE 802 may transmit a sidelink message (e.g., resource availability report 818) indicating a second set of available resources that are available based on the second measurement threshold. In some aspects, 1006 may be performed by the SL component 1346 of FIG. 13. In some aspects, the second set of resources may be indicated in a resource availability report that includes a list of each resource in the second set of available resources based on the sensing. In some aspects, the second set of resources may be indicated in a resource availability report that includes a top percentage of available resources based on the second measurement threshold.

[0109] In some aspects, the UE may schedule at least one available resource of the second set of available resources to the second UE at 1008. For example, the UE 802 may schedule at least one available resource of the second set of available resources to the second UE 804 by transmitting a reservation 820. The at least one available resource of the second set of available resources to the second UE may be used by the second UE to transmit a transmission, such as transmission 824, to the UE. In some aspects, the UE may not schedule the at least one available resource of the second set of available resources to the second UE. In some aspects, 1008 may be performed by the SL component 1346 of FIG. 13.

[0110] In some aspects, the UE may receive a sensing-based sidelink communication carried by at least one available resource of the second set of available resources from a second UE at 1010. For example, the UE 802 may receive a sensing-based sidelink communication (e.g., transmission 824) carried by at least one available resource of the second set of available resources from a second UE 804.

[0111] 11 is a flowchart 1100 of a method of wireless communication. The method may be performed by a UE (e.g., UE 104, UE 702, UE 802, device 1302). The method may enable a receiving UE to re-identify a first set of available resources that may be suitable for transmission of the transmitting UE by adjusting a measurement threshold, resulting in a more efficient sidelink transmission.

[0112] At 1102, the UE may perform sensing measurements on one or more SL resources to determine one or more available resources for sidelink communication. For example, at 810, the UE 802 may perform sensing measurements on one or more SL resources to determine one or more available resources for sidelink communication. In some aspects, 1102 may be performed by the sensing component 1342 of FIG. 13.

[0113] At 1104, the UE may transmit a sidelink message including a resource availability report indicating a subset of the one or more available resources. For example, the UE 802 may transmit a sidelink message including a resource availability report (e.g., resource availability report 818) indicating a subset of the one or more available resources. In some aspects, 1104 may be performed by the SL component 1346 of FIG. 13.

[0114] 12 is a flowchart 1200 of a method of wireless communication. The method may be performed by a UE (e.g., UE 104, UE 702, UE 802, device 1302). The method may enable a receiving UE to re-identify a first set of available resources that may be suitable for transmission of the transmitting UE by adjusting a measurement threshold, resulting in a more efficient sidelink transmission.

[0115] At 1202, the UE may perform sensing measurements on one or more SL resources to determine one or more available resources for sidelink communication. For example, at 810, the UE 802 may perform sensing measurements on one or more SL resources to determine one or more available resources for sidelink communication. In some aspects, 1202 may be performed by the sensing component 1342 of FIG. 13.

[0116] At 1204, the UE may rank the one or more available resources based on the sensing measurements. The subset of the one or more available resources may correspond to a portion of the one or more available resources having the lowest or highest sensing measurements. For example, the UE 802 may rank the one or more available resources based on the sensing measurements. In some aspects, 1204 may be performed by the availability component 1344 of FIG. 13.

[0117] At 1206, the UE may adjust a sensing measurement threshold based on the first set of available resources being less than the availability threshold, and further based on one or more of a packet priority associated with the sidelink communication associated with the second UE, an MCS associated with the second UE, a cast type associated with the second UE, a remaining packet delay budget associated with the sidelink communication associated with the second UE, a communication range specification associated with the second UE, a HARQ ACK utilization status associated with the sidelink communication associated with the second UE, a CBR, or a distance between the UE and the second UE. For example, at 814, the UE 802 may adjust the measurement threshold. In some aspects, 1206 may be performed by the availability component 1344 of FIG. 13.

[0118] At 1208, the UE may transmit a sidelink message including a resource availability report indicating a subset of the one or more available resources. For example, the UE 802 may transmit a sidelink message including a resource availability report (e.g., resource availability report 818) indicating a subset of the one or more available resources. In some aspects, 1208 may be performed by the SL component 1346 of FIG. 13. In some aspects, the subset corresponds to a percentage value of the one or more available resources of the one or more SL resources. In some aspects, the resource availability report indicates a ranking of each resource in the subset of the one or more available resources.

[0119] 13 is a diagram 1300 illustrating an example of a hardware implementation of an apparatus 1302. The apparatus 1302 may be a UE, a component of a UE, or may implement the functionality of a UE. In some aspects, the apparatus 1302 may include a cellular baseband processor 1304 (also referred to as a modem) coupled to a cellular RF transceiver 1322. In some aspects, the apparatus 1302 may further include one or more subscriber identity module (SIM) cards 1320, a secure digital (SD) card 1308, and an application processor 1306 coupled to a screen 1310, a Bluetooth module 1312, a wireless local area network (WLAN) module 1314, a global positioning system (GPS) module 1316, or a power source 1318. The cellular baseband processor 1304 communicates with the UE 104 and / or the BS 102 / 180 through the cellular RF transceiver 1322. The cellular baseband processor 1304 may include a computer readable medium / memory. The computer readable medium / memory may be non-transitory. The cellular baseband processor 1304 is responsible for general processing, including the execution of software stored in the computer readable medium / memory. The software, when executed by the cellular baseband processor 1304, causes the cellular baseband processor 1304 to perform various functions described above. The computer readable medium / memory may also be used to store data that is manipulated by the cellular baseband processor 1304 when executing the software. The cellular baseband processor 1304 further includes a receiving component 1330, a communications manager 1332, and a transmitting component 1334. The communications manager 1332 includes one or more of the shown components. The components in the communications manager 1332 may be stored in the computer readable medium / memory and / or configured as hardware in the cellular baseband processor 1304.The cellular baseband processor 1304 may be a component of the UE 350 and may include the memory 360 and / or at least one of the TX processor 368, the RX processor 356, and the controller / processor 359. In one configuration, the apparatus 1302 may be a modem chip and may include only the baseband processor 1304, while in another configuration, the apparatus 1302 may be an entire UE (e.g., see 350 in FIG. 3) and may include additional modules of the apparatus 1302.

[0120] The communications manager 1332 may include a sensing component 1342 configured to perform sensing on one or more SL resources to identify a first set of available resources or perform sensing measurements on one or more SL resources to determine one or more available resources for sidelink communications, e.g., as described in connection with 902 of FIG. 9, 1002 of FIG. 10, 1102 of FIG. 11, or 1202 of FIG. 12.

[0121] The communications manager 1332 may further include an availability component 1344 that may be configured to adjust the first measurement threshold to a second measurement threshold based on the size of the first set of available resources being less than the availability threshold, and to rank one or more available resources based on the sensing measurements or adjust the measurement thresholds, as described with respect to 904 in FIG. 9 , 1004 in FIG. 10 , or 1204 and 1206 in FIG. 12 .

[0122] The communications manager 1332 may further include an SL component 1346 that may be configured to: send a sidelink message indicating the second set of available resources based on the second measurement threshold; schedule at least one available resource of the second set of available resources for the second UE; receive a sidelink communication based on the sensing carried by the at least one available resource of the second set of available resources from the second UE; or send a sidelink message including a resource availability report indicating a subset of the one or more available resources, e.g., as described with respect to 906 of FIG. 9 , 1006, 1008, or 1010 of FIG. 10 , 1104 of FIG. 11 , or 1208 of FIG. 12 .

[0123] The apparatus may include additional components that perform each of the blocks of the algorithms in the flowcharts of Figures 9-12. Thus, each block in the flowcharts of Figures 9-12 may be performed by a component, and the apparatus may include one or more of those components. The components may be one or more hardware components specifically configured to perform the described processes / algorithms, implemented by a processor configured to perform the described processes / algorithms, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0124] As shown, the apparatus 1302 may include various components configured for various functions. In one configuration, the apparatus 1302, and in particular the cellular baseband processor 1304, may include means for performing sensing on one or more of the SL resources to identify a set of available resources, such as a sensing component 1342 or a transceiver. The cellular baseband processor 1304 may further include means for raising a first measurement threshold to a second measurement threshold based on a size of the first set of available resources being less than an availability threshold, such as an availability component 1344. The cellular baseband processor 1304 may further include means for transmitting a sidelink message indicating a second set of available resources based on the second measurement threshold, such as an SL component 1346 or a transceiver. The cellular baseband processor 1304 may further include means for receiving a sidelink communication from a second UE based on the sensing, carried by at least one available resource of the second set of available resources, such as the SL component 1346 or a transceiver. The cellular baseband processor 1304 may further include means for scheduling at least one available resource of the second set of available resources for the second UE, such as an SL component 1346 or a transceiver. The cellular baseband processor 1304 may further include means for performing sensing measurements on one or more SL resources to determine one or more available resources for sidelink communications, such as a sensing component 1342 or a transceiver. The cellular baseband processor 1304 may further include means for ranking the one or more available resources based on the sensing measurements, such as an availability component 1344. The cellular baseband processor 1304 may further include means for adjusting a measurement threshold, such as the availability component 1344.The cellular baseband processor 1304 may further include means for transmitting a sidelink message including a resource availability report indicating a subset of one or more available resources, such as the SL component 1346 or a transceiver. The means may be one or more of the components of the apparatus 1302 configured to perform the functions recited by the means. As described above, the apparatus 1302 may include the TX processor 368, the RX processor 356, and the controller / processor 359. Thus, in one configuration, the means may be the TX processor 368, the RX processor 356, and the controller / processor 359 configured to perform the functions recited by the means.

[0125] It is understood that the particular order or hierarchy of the blocks in the disclosed processes / flow charts is illustrative of example approaches. Based on design preferences, it is understood that the particular order or hierarchy of the blocks in the processes / flow charts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in an example order, and are not intended to be limited to the particular order or hierarchy presented.

[0126] The above description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects set forth herein, but are to be accorded the widest scope consistent with the claim language, and reference to an element in the singular is intended to mean "one or more," and not "one and only," unless so expressly stated. Terms such as "if," "when," and "while" should be construed to mean "under the condition that," rather than implying an immediate temporal relationship or reaction. That is, these phrases, for example, "when," do not imply an immediate action in response to or while an action is being performed, but merely imply that an action is performed when a condition is met, but without requiring any specific or immediate temporal constraint for the action to be performed. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects. Unless otherwise specified, the term "some" refers to one or more. Combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," "A, B, C, or any combination thereof" include any combination of A, B, and / or C, and may include multiple A, multiple B, or multiple C.Specifically, combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," "A, B, C, or any combination thereof" may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, and any such combination may include one or more members of A, B, or C. All structural and functional equivalents to the elements of the various embodiments described throughout this disclosure that are known or that later become known to those of skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be made public, regardless of whether such disclosure is expressly recited in the claims. Words such as "module," "mechanism," "element," "device," and the like may not be substitutes for the word "means." Therefore, no claim element should be construed as a means-plus-function unless the element is expressly recited using the phrase "means for."

[0127] The following aspects are exemplary only and can be combined with, but not limited to, other aspects or teachings described herein.

[0128] Aspect 1 is an apparatus for wireless communication in a first UE, comprising a memory and at least one processor coupled to the memory, wherein the memory and the at least one processor are configured to perform sensing on one or more SL resources to identify a first set of available resources, adjust a first measurement threshold to a second measurement threshold based on a size of the first set of available resources being less than an availability threshold, and transmit a sidelink message indicating the second set of available resources based on the second measurement threshold.

[0129] Example 2 is the apparatus of example 1, wherein the at least one processor and memory are further configured to receive, from a second UE, sidelink communication carried by at least one available resource of the second set of available resources.

[0130] Example 3 is the apparatus of example 1 or 2, wherein the at least one processor coupled to the memory is further configured to schedule at least one available resource in the second set of available resources for the second UE.

[0131] Example 4 is the device of any of Examples 1 to 3, wherein the first measurement threshold is a first SIR ratio value, the second measurement threshold is a second SIR ratio value, and the first SIR ratio value is higher than the second SIR ratio value.

[0132] Example 5 is the apparatus of any of Examples 1 to 4, wherein the first SIR ratio value or the second SIR ratio value is based on one or more functions of a priority associated with a sidelink communication associated with the second UE or an MCS associated with the second UE.

[0133] Example 6 is the device of any of examples 1 to 5, wherein the first measurement threshold is a first RSRQ threshold, the second measurement threshold is a second RSRQ threshold, and the first RSRQ threshold is higher than the second RSRQ threshold.

[0134] Example 7 is the apparatus of any of examples 1-6, wherein the availability threshold comprises a percentage of available resources from the one or more SL resources.

[0135] Example 8 is the apparatus of any of examples 1-7, wherein the availability threshold comprises a threshold size of available resources from the one or more SL resources.

[0136] Example 9 is the apparatus of any of examples 1 to 8, wherein the second set of available resources is indicated in a resource availability report including a list of each resource in the second set of available resources.

[0137] Example 10 is the apparatus of any of examples 1-9, wherein the second set of available resources is indicated in a resource availability report that includes a top percentage of the available resources based on a second measurement threshold.

[0138] Example 11 is the apparatus of any of Examples 1-10, wherein the second measurement threshold is based on one or more of a packet priority associated with the sidelink communication related to the second UE, an MCS associated with the second UE, a cast type associated with the second UE, a remaining packet delay budget associated with the sidelink communication related to the second UE, a communication range specification associated with the second UE, a HARQ ACK utilization status associated with the sidelink communication related to the second UE, a CBR, or a distance between the first UE and the second UE.

[0139] Example 12 is the apparatus of any of Examples 1-11, further comprising an antenna coupled to the at least one processor.

[0140]

[0023] Aspect 13 is an apparatus for wireless communication in a first UE, comprising: a memory; and at least one processor coupled to the memory, wherein the at least one processor is configured to perform sensing measurements on one or more SL resources to determine one or more available resources for sidelink communication; and to transmit a sidelink message including a resource availability report indicating a subset of the one or more available resources.

[0141] Example 14 is the apparatus of example 13, wherein the subset corresponds to a percentage value of one or more available resources of the one or more SL resources.

[0142] Example 15 is the apparatus of example 13 or 14, wherein the at least one processor and memory are further configured to rank the one or more available resources based on the sensing measurements, the subset of the one or more available resources corresponding to a portion of the one or more available resources having a lowest sensing measurement value.

[0143] Example 16 is the apparatus of any of examples 13-15, wherein the resource availability report indicates a ranking of each resource among a subset of the one or more available resources.

[0144] Example 17 is the apparatus of any of Examples 13-16, wherein the at least one processor coupled to the memory is further configured to adjust the sensing measurement threshold based on the first set of available resources being less than an availability threshold, and further based on one or more of a packet priority associated with the sidelink communication related to the second UE, an MCS associated with the second UE, a cast type associated with the second UE, a remaining packet delay budget associated with the sidelink communication related to the second UE, a communication range specification associated with the second UE, a HARQ ACK utilization status associated with the sidelink communication related to the second UE, a CBR, or a distance between the UE and the second UE.

[0145] Example 18 is the apparatus of any of Examples 13-17, further comprising an antenna coupled to the at least one processor.

[0146] Example 19 is a method of wireless communication for implementing any of Examples 1 to 12.

[0147] Example 20 is an apparatus for wireless communication that includes means for implementing any of Examples 1-12.

[0148] Aspect 21 is a computer-readable medium storing computer-executable code that, when executed by a processor, causes the processor to implement any of aspects 1-12.

[0149] Example 22 is a method of wireless communication for implementing any of Examples 13 to 18.

[0150] Example 23 is an apparatus for wireless communication, the apparatus including means for implementing any of Examples 13 to 18.

[0151] Aspect 24 is a computer-readable medium storing computer-executable code that, when executed by a processor, causes the processor to implement any of aspects 13-18. [Explanation of symbols]

[0152] 102 Base station 104UE 105 DU 106 CU 107 RSU 109RU 110 Geographic Coverage Areas 111 IAB nodes 120 Communication Links 132 1st backhaul link 134 3rd Backhaul Link 150 Wi-Fi access points 152 STA 154 Communication Links 158 D2D communication links 160 EPC 162 MME 164 Other MMEs 166 Serving Gateway 168 MBMS Gateway 170 BM-SC 172 PDN Gateway 174 HSS 176 IP Services 180 Base Station / RAN 182 Beamforming 184 Second Backhaul Link 190 Core Network 192 AMF 193 Other AMF 194 SMF 195 UPF 196 U.D.M. 197 IP Services 198 SL Components 310 First wireless communication device 316 TX Processor 318 Transceiver 320 Antenna 350 Second wireless communication device 352 Antenna 354 Transceiver 356 RX processor 358 Channel Estimator 359 Controller / Processor 360 Memory 368 TX Processor 370 RX Processor 374 Channel Estimator 375 Controller / Processor 376 Memory 401 Range 402 First UE 406 Second UE 408 The third UE 410 Sidelink transmission 412 Sidelink transmission 502 Initial data transmission 504 First Data Retransmission 506 Second Data Retransmission 508 Current data transmission 510 First Data Retransmission 512 Second Data Retransmission 602 Sensing Section 604 Resource Reselection Section 650 Resource Reselection Trigger 702UE 704UE 706UE 712 UE-A 714UE-B 716 Inter-UE cooperation information 718 Sidelink transmission 719 UE-C 722 Resource Availability Information 724 Send 802UE 804UE 812 Resource Availability Report 816 Resource Availability Report 818 Resource Availability Report 820 Resource Reservation 824 Send 1302 Equipment 1304 Baseband Processor 1306 Application Processor 1308 SD card 1310 Screen 1312 Bluetooth Module 1314 WLAN Module 1316 GPS Module 1318 Power supply 1320 SIM card 1322 RF Transceiver 1330 Receiving Component 1332 Communications Manager 1334 Transmission Component 1342 Sensing Components 1344 Availability Component 1346 SL Components

Claims

1. 1. An apparatus for wireless communication in a first user equipment (UE), the apparatus comprising: Memory and one or more processors coupled to the memory, wherein the one or more processors cause the first UE to: performing sensing on one or more sidelink (SL) resources to identify a first set of one or more preferred resources or a first set of one or more non-preferred resources for transmission from the second UE; adjusting a first measurement threshold to a second measurement threshold based on a size of a first set of available resources associated with the first set of one or more preferred resources or the first set of one or more non-preferred resources for transmission from the second UE being less than an availability threshold; transmitting inter-UE coordination information to the second UE indicating a second set of one or more preferred resources or a second set of one or more non-preferred resources based on the second measurement threshold, wherein the second set of one or more preferred resources or the second set of one or more non-preferred resources indicates at least one preferred resource for the transmission from the second UE or indicates at least one non-preferred resource for the transmission from the second UE; An apparatus configured to cause

2. the one or more processors further comprising:

10. The apparatus of claim 1, configured to receive, from the second UE, a sidelink communication carried by at least one available resource of the second set of available resources.

3. The one or more processors further comprising: The apparatus of claim 2 , configured to schedule the at least one available resource in the second set of available resources for the second UE.

4. The device described in claim 1, wherein the first signal-to-interference (SIR) ratio value or the second SIR ratio value is based on one or more functions of a priority associated with sidelink communication associated with the second UE or a modulation and coding scheme (MCS) associated with the second UE.

5. The apparatus of claim 1 , wherein the availability threshold comprises a percentage of available resources from the one or more SL resources or a threshold size of available resources from the one or more SL resources.

6. the second set of available resources being: a list of each resource in said second set of available resources; or a top percentage of available resources based on the second measurement threshold; 10. The apparatus of claim 1, wherein a top percentage of available resources are arranged in descending order, starting with the available resource associated with the measurement furthest from the measurement threshold.

7. 10. The apparatus of claim 1, further comprising: an antenna coupled to the one or more processors; and wherein the second measurement threshold is based on one or more of: a packet priority associated with sidelink communication associated with the second UE; a modulation and coding scheme (MCS) associated with the second UE; a cast type associated with the second UE; a remaining packet delay budget associated with the sidelink communication associated with the second UE; a communication range specification associated with the second UE; a hybrid automatic repeat request (HARQ) acknowledgment (ACK) utilization status associated with the sidelink communication associated with the second UE; and a channel busy ratio (CBR).

8. The device described in claim 1, wherein the UE-to-UE coordination information indicates the second set of one or more preferred resources, and the second set of one or more preferred resources includes a second set of available resources.

9. The device described in claim 1, wherein the UE-to-UE coordination information indicates the second set of one or more unpreferred resources.

10. The device of claim 1, wherein the first measurement threshold and the second measurement threshold are for reference signal received power (RSRP) measurements.

11. The device of claim 1, wherein, in order to adjust the first measurement threshold to the second measurement threshold, the one or more processors are configured to cause the first UE to adjust the first measurement threshold to the second measurement threshold based on the size of the first set of available resources associated with the first set of one or more preferred resources being less than the availability threshold.

12. The device of claim 1, wherein, in order to adjust the first measurement threshold to the second measurement threshold, the one or more processors are configured to cause the first UE to adjust the first measurement threshold to the second measurement threshold based on the size of the first set of available resources associated with the first set of one or more unpreferred resources being less than the availability threshold.

13. 1. A method for wireless communication in a first user equipment (UE), comprising: performing sensing on one or more sidelink (SL) resources to identify a first set of one or more preferred resources or a first set of one or more non-preferred resources for transmission from the second UE; adjusting a first measurement threshold to a second measurement threshold based on a size of a first set of available resources associated with the first set of one or more preferred resources or the first set of one or more non-preferred resources for transmission from the second UE being less than an availability threshold; transmitting inter-UE coordination information to the second UE indicating a second set of one or more preferred resources or a second set of one or more non-preferred resources based on the second measurement threshold, wherein the second set of one or more preferred resources or the second set of one or more non-preferred resources indicates at least one preferred resource for the transmission from the second UE or indicates at least one non-preferred resource for the transmission from the second UE; A method comprising:

14. The method of claim 13, further comprising receiving sidelink communication from the second UE carried by at least one available resource of the second set of available resources.

15. A computer-readable storage medium comprising instructions that, when executed by a computer, cause the computer to perform the method of claim 13 or 14.

Images