New radio (NR) sidelink (SL) channel access using virtual collision metric

Abstract

Wireless communications systems and methods related to channel congestion estimation based on a virtual collision metric are provided. A user equipment (UE) can select a plurality of resources from a pool of sidelink resources. The UE can request an evaluation of availability of the plurality of resources, and can receive an indication of availability of the plurality of resources. The UE can also transmit a first sidelink transmission based on a virtual collision metric associated with the indication of availability of the plurality of resources.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to U.S. Patent Application No. 17 / 247,066, filed November 25, 2020, the entire contents of which are incorporated herein by reference as fully set forth below and for all applicable purposes. Technical Field

[0003] This application relates to wireless communication systems, and more specifically, to sidelink channel access using virtual collision metrics. Background Technology

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, message sending and receiving, and broadcasting. These systems can support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Wireless multiple access communication systems may include multiple base stations (BSs), each supporting communication from multiple communication devices (which may also be referred to as user equipment (UE)) simultaneously.

[0005] To meet the growing demand for extended mobile broadband connectivity, wireless communication technologies are evolving from Long Term Evolution (LTE) to Next Generation New Radio (NR), often referred to as fifth generation (5G). For example, NR is designed to provide lower latency, higher bandwidth or throughput, and greater reliability than LTE. NR is designed to operate across wide frequency bands, from low-frequency bands below approximately 1 GHz and mid-frequency bands from approximately 1 GHz to approximately 6 GHz to high-frequency bands such as millimeter wave (mmWave) bands. NR is also designed to operate across different spectrum types, from licensed spectrum to unlicensed and shared spectrum. Spectrum sharing allows operators to opportunistically aggregate spectrum to dynamically support high-bandwidth services. Spectrum sharing can extend the benefits of NR technology to operational entities that may not have access to licensed spectrum.

[0006] In wireless communication networks, a Base Station (BS) can communicate with a UE in both uplink and downlink directions. LTE introduces sidelinks to allow a UE to send data to another UE without tunneling through the BS and / or the associated core network. LTE sidelink technology has been extended to provide device-to-device (D2D) communication, vehicle-to-everything (V2X) communication, and / or cellular vehicle-to-everything (C-V2X) communication. Similarly, NR can be extended to support sidelink communication, D2D communication, V2X communication, and / or C-V2X on licensed and / or unlicensed frequency bands. Summary of the Invention

[0007] The following outlines some aspects of this disclosure to provide a basic understanding of the techniques discussed. This overview is not a comprehensive summary of all intended features of this disclosure, nor is it intended to identify key or essential elements of all aspects of this disclosure, nor to depict the scope of any or all aspects of this disclosure. Its sole purpose is to present some concepts of one or more aspects of this disclosure in an overview form as a prelude to the more detailed description that follows.

[0008] For example, in one aspect of this disclosure, a method of wireless communication performed by a user equipment (UE) includes selecting a plurality of resources from a sidelink resource pool. The method may further include requesting an assessment of the availability of the plurality of resources and receiving an indication of the availability of the plurality of resources. Furthermore, the method may include transmitting a first sidelink transmission based on a virtual collision metric associated with the indication of the availability of the plurality of resources.

[0009] In an additional aspect of this disclosure, a method for wireless communication performed by a user equipment (UE) includes: performing measurement-only sensing in a sidelink resource pool. Performing measurement-only sensing may include: selecting a plurality of measurement-only resources from the sidelink resource pool and obtaining the availability of the plurality of measurement-only resources. The method may further include: transmitting a first sidelink transmission based on a virtual collision metric associated with the availability of the plurality of measurement-only resources obtained from the measurement-only sensing.

[0010] In an additional aspect of this disclosure, a user equipment (UE) includes a processor configured to select a plurality of resources from a sidelink resource pool. The processor may also be configured to request an assessment of the availability of the plurality of resources and to receive an indication of the availability of the plurality of resources. The UE may further include a transceiver communicating with the processor and configured to transmit a first sidelink transmission based on a virtual collision metric associated with the indication of the availability of the plurality of resources.

[0011] In an additional aspect of this disclosure, a user equipment (UE) includes a processor configured to perform measurement-only sensing in a sidelink resource pool. The processor configured to perform measurement-only sensing may also be configured to select a plurality of measurement-only resources from the sidelink resource pool and obtain the availability of the plurality of measurement-only resources. The UE may further include a transceiver communicating with the processor and configured to transmit a first sidelink transmission based on a virtual collision metric associated with the availability of the plurality of measurement-only resources obtained from the measurement-only sensing.

[0012] Other aspects, features, and embodiments of the invention will become apparent to those skilled in the art when read in conjunction with the accompanying drawings and specific exemplary embodiments thereof. While various features of the invention may be discussed with reference to certain embodiments and the drawings below, all embodiments of the invention may include one or more of the advantageous features discussed herein. That is, while one or more embodiments may be discussed as having certain advantageous features, these features may also be used according to the various embodiments of the invention discussed herein. Similarly, while exemplary embodiments may be discussed below as embodiments of devices, systems, or methods, it should be understood that such exemplary embodiments may be implemented in various devices, systems, and methods. Attached Figure Description

[0013] Figure 1 A wireless communication network according to some aspects of this disclosure is shown.

[0014] Figure 2 A wireless communication network providing side link communication according to some aspects of this disclosure is shown.

[0015] Figure 3A This is a sequence diagram illustrating an autonomous side-link sensing method according to some aspects of this disclosure.

[0016] Figure 3B An autonomous side-link sensing scheme based on some aspects of this disclosure is illustrated.

[0017] Figure 4 An autonomous side-link sensing scheme based on some aspects of this disclosure is illustrated.

[0018] Figure 5 A drawing of a sidelink transmission scenario is shown, illustrating some aspects of this disclosure.

[0019] Figure 6A The sidelink resource selection scheme utilizing the contention window is illustrated in various aspects of this disclosure.

[0020] Figure 6B The competition window size is shown to be dynamically adjusted over time according to some aspects of this disclosure.

[0021] Figure 7 This is a sequence diagram of a virtual collision-based channel access method associated with the use of measurement resources only, based on some aspects of this disclosure.

[0022] Figure 8 This is a virtual collision-based channel access method based on some aspects of this disclosure, which is associated with the use of transmission resources and measurement resources only.

[0023] Figure 9 This is a sequence diagram illustrating a method for optimizing channel access configuration based on virtual collisions, according to some aspects of this disclosure.

[0024] Figure 10 This is a sequence diagram illustrating a method for configuring a virtual conflict measurement report according to some aspects of this disclosure.

[0025] Figure 11 This is a block diagram of an exemplary base station (BS) based on some aspects of this disclosure.

[0026] Figure 12 This is a block diagram of an exemplary user equipment (UE) based on some aspects of this disclosure.

[0027] Figure 13 This is a flowchart of a wireless communication method based on some aspects of this disclosure.

[0028] Figure 14 This is a flowchart of a wireless communication method based on some aspects of this disclosure. Detailed Implementation

[0029] The specific embodiments described below with reference to the accompanying drawings are intended as descriptions of various configurations and are not intended to represent only configurations in which the concepts described herein can be practiced. The specific embodiments include detailed information to provide a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts can be practiced without these specific details. In some cases, well-known structures and components are shown in block diagram form to avoid obscuring these concepts.

[0030] This disclosure generally relates to wireless communication systems, also referred to as wireless communication networks. In various embodiments, the techniques and apparatus described can be used in wireless communication networks such as: Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, Single Carrier FDMA (SC-FDMA) networks, LTE networks, Global System for Mobile Communications (GSM) networks, 5G or New Radio (NR) networks, and other communication networks. As described herein, the terms "network" and "system" are used interchangeably.

[0031] OFDMA networks can implement radio technologies such as Evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, and flash-OFDM. UTRA, E-UTRA, and GSM are part of the Universal Mobile Telecommunications System (UMTS). Specifically, Long Term Evolution (LTE) is a UMTS version using E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents provided by an organization called the 3rd Generation Partnership Project (3GPP), and cdma2000 is described in documents from an organization called 3rd Generation Partnership Project 2 (3GPP2). These various radio technologies and standards are either known or under development. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration between telecommunications associations aimed at defining globally applicable third-generation (3G) mobile phone specifications. 3GPP Long Term Evolution (LTE) is a 3GPP project aimed at improving the UMTS mobile phone standard. 3GPP defines specifications for next-generation mobile networks, mobile systems, and mobile devices. This disclosure relates to the evolution of wireless technologies from LTE, 4G, 5G, NR, and later versions, in which new and different sets of radio access technologies or radio air interfaces are used to share access to the radio spectrum between networks.

[0032] Specifically, 5G networks consider a variety of deployments, spectrums, services, and devices that can be implemented using a unified air interface based on OFDM. To achieve these goals, in addition to developing new radio technologies for 5G NR networks, further enhancements to LTE and LTE-A are also considered. 5G NR will be able to scale to cover the following: (1) to areas with ultra-high density (e.g., ~1M nodes / km). 2 (1) Large-scale Internet of Things (IoT) with mission-critical control, robust security to protect sensitive personal, financial or confidential information, ultra-high reliability (e.g., ~99.9999% reliability), ultra-low latency (e.g., ~1ms), and extensive mobility or lack thereof; (2) Enhanced mobile broadband, including extremely high capacity (e.g., ~10Tbps / km). 2 Extreme data rates (e.g., multi-Gbps rates, 100+Mbps user experience rates), and deep awareness with advanced discovery and optimization.

[0033] 5G NR communication systems can be implemented using optimized OFDM-based waveforms with scalable digital schemes and transmission time intervals (TTI). Additional features may include: a common, flexible framework for efficiently multiplexing services and features using dynamic, low-latency time-division duplex (TDD) / frequency-division duplex (FDD) designs; and advanced wireless technologies such as massive MIMO, robust millimeter-wave (mmWave) transmission, advanced channel coding, and device-centric mobility. The scalability of the digital scheme in 5G NR (with subcarrier spacing scaling) can efficiently address the operation of different services across different spectrums and deployments. For example, in various outdoor and macro coverage deployments using FDD / TDD implementations below 3 GHz, the subcarrier spacing can be, for example, 15 kHz over bandwidths (BW) of 5, 10, or 20 MHz. For other various outdoor and small-cell coverage deployments using TDD above 3 GHz, the subcarrier spacing can be 30 kHz over an 80 / 100 MHz BW. For various other indoor broadband implementations, using TDD on the unlicensed portion of the 5 GHz band, the subcarrier spacing can be 60 kHz over a 160 MHz BW. Finally, for various deployments using mmWave components for TDD transmission at 28 GHz, the subcarrier spacing can be 120 kHz over a 500 MHz BW.

[0034] 5G NR's scalable digital schemes facilitate scalable TTIs for varying latency and Quality of Service (QoS) requirements. For example, shorter TTIs can be used for low latency and high reliability, while longer TTIs can be used for higher spectral efficiency. Efficient multiplexing of long and short TTIs allows transmissions to begin at symbol boundaries. 5G NR also considers self-contained integrated subframe designs that incorporate UL / downlink scheduling information, data, and acknowledgments within the same subframe. These self-contained integrated subframes support communication in unlicensed or contention-based shared spectrum and adaptive UL / downlink (which can be flexibly configured on a per-cell basis to dynamically switch between UL and downlink to meet current service demands).

[0035] Various other aspects and features of this disclosure are further described below. It should be apparent that the teachings herein can be embodied in various forms, and any particular structure, function, or both disclosed herein are merely representative and not limiting. Based on the teachings herein, those skilled in the art will understand that an aspect disclosed herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement an apparatus or method of practice. Additionally, an apparatus or method of practice can be implemented using structures, functions, or structures and functions other than or different from one or more aspects set forth herein. For example, a method can be implemented as part of a system, device, apparatus, and / or as instructions stored on a computer-readable medium for execution on a processor or computer. Furthermore, an aspect may include at least one element of the claims.

[0036] Sidelink communication refers to communication between user equipment (UE) without tunneling through a base station (BS) and / or core network. Sidelink communication can occur on the Physical Sidelink Control Channel (PSCCH) and the Physical Sidelink Shared Channel (PSSCH). The PSCCH and PSSCH are similar to the Physical Downlink Control Channel (PDCCH) and Physical Downlink Shared Channel (PDSCH) in downlink (DL) communication between the BS and UE. For example, the PSCCH may carry sidelink control information (SCI), and the PSSCH may carry sidelink data (e.g., user data). Each PSCCH is associated with a corresponding PSSCH, where the SCI in the PSCCH may carry reservation and / or scheduling information for sidelink data transmission in the associated PSSCH. Use cases for sidelink communication can include V2X, enhanced mobile broadband (eMBB), industrial IoT (IIoT), and / or NR-Lite.

[0037] As used herein, the term "sidelink UE" can refer to a user equipment apparatus that performs device-to-device communication or other types of communication with another user equipment independently of any tunneling through a BS (e.g., gNB) and / or associated core network. As used herein, the term "sidelink transmitting UE" can refer to a user equipment apparatus that performs sidelink transmitting operations. As used herein, the term "sidelink receiving UE" can refer to a user equipment apparatus that performs sidelink receiving operations. A sidelink UE can operate as a sidelink transmitting UE at one time and as a sidelink receiving UE at another time.

[0038] For sidelinks on licensed spectrum, NR supports two Radio Resource Allocation (RRA) modes: Mode-1 RRA and Mode-2 RRA. Mode-1 RRA supports network-controlled RRA, which can be used for sidelink communication within coverage area. For example, the serving BS can determine radio resources on behalf of the sidelink UE and send instructions for radio resources to the sidelink UE. Mode-2 RRA supports autonomous RRA, which can be used for sidelink UEs outside coverage area or partially covered UEs. For example, sidelink UEs outside coverage area or partially covered UEs can have a pre-configured sidelink resource pool and can select radio resources from the pre-configured pool for sidelink communication.

[0039] For Mode-2 RRA, the sidelink UE can perform sensing in the sidelink resource pool. This sensing may include decoding the SCI and / or measuring signal energy in the channel. For SCI decoding, the UE can blindly decode the SCI from the PSCCH of each resource. If decoding is successful, the UE can record the decoded SCI. For signal measurement, the UE can receive signals from each resource and calculate the Reference Received Power (RSRP) and / or Received Signal Strength Indicator (RSSI) for each resource. The UE can also record the signal measurement results. The UE can generate packets for transmission (e.g., Medium Access Control (MAC), Packet Data Unit (PDU)). Once packets are generated, the UE can trigger resource selection. The UE can define a sensing window and a resource selection window in the resource pool for the time of triggering resource selection. The sensing window can be located before the trigger, and the resource selection window can be located after the trigger. The UE can determine the sensing window and resource selection window based on a set of parameters, which can be pre-configured and / or pre-determined. The UE can identify candidate resources within the resource selection window based on past sensing results obtained within the sensing window (e.g., decoded SCIs and / or signal measurements). That is, the UE can predict resource usage within the resource selection window based on past sensing results. The UE can randomly select resources from identified candidate resources. The selected resources can be within a fixed subchannel in the frequency domain and a fixed sidelink time slot in the time domain. The UE can indicate a reservation for the selected resource. That is, the reservation can have the granularity of a sidelink time slot. The reservation can facilitate Channel Sense Multiple Access (CSMA) between sidelink UEs (e.g., in a sidelink intra-system). In some cases, the UE can continue sensing and perform a last-minute evaluation of the reserved resource (e.g., a T3 duration before the actual transmission time) to check if the reserved resource has been preempted by another UE. If the last-minute evaluation passes (indicating that the reserved resource remains available), the UE can use the selected resource to transmit sidelink transmissions (e.g., including SCI in PSCCH and packets in PSSCH). In some cases, the UE can select multiple resources from the candidate resources, for example, a first resource for initial packet transmission and a second resource for packet retransmission when Hybrid Automatic Repeat Request (HARQ) is used for packet transmission.

[0040] In some cases, a sidelink UE can measure and / or determine the Channel Busy Rate (CBR) for packet transmission. For example, to transmit packets on a specific channel, the UE can determine the CBR for that channel before transmission. In some cases, the UE can determine the CBR for that channel based on decoded SCI, RSRP, and / or RSSI, which the UE can receive via communication with another sidelink UE. Furthermore, the UE can be configured with a mapping from CBR to Channel Utilization (CR) that regulates channel access. For example, a larger CBR value can be mapped to a smaller CR value, and vice versa. In this way, channel access attempts may become increasingly restricted as traffic on the channel increases (e.g., the CBR of the channel increases). However, for communication within licensed spectrum, inter-channel leakage, which may be caused by low-complexity receiver implementations, can lead to erroneous CBR measurements and / or estimates at the UE. Furthermore, when NR is deployed on unlicensed spectrum (e.g., NR-unlicensed (NR-U)), the presence of other RATs in the unlicensed band can lead to erroneous CBR estimates at the UE. As an illustrative example, a subchannel might be detected as busy in the CBR estimate when it is actually occupied by another RAT. These erroneous CBR estimates can lead to channel access uncertainty and / or reduced communication efficiency within the network, regardless of whether the spectrum is licensed or unlicensed. For example, if a sidelink UE detects a human-caused (e.g., erroneously) high CBR estimate mapped to a small CR value, the sidelink UE might be delayed or suppressed by other RATs (e.g., the sidelink UE might be unable to access the channel). Therefore, more reliable indications of network traffic and / or channel congestion can improve communication efficiency within the network.

[0041] As used herein, the term "virtual conflict" can refer to an event detected during a last-minute evaluation (e.g., re-evaluation) of a resource (e.g., a time-frequency resource). Specifically, a virtual conflict for a resource may occur when a first UE selects a resource for transmission and, during a last-minute evaluation of the resource prior to transmission, determines that a second UE has already reserved the resource (e.g., via SCI). For example, the first UE may receive a reselection flag associated with the resource, indicating that the resource is unavailable. In some examples, a reselection flag value of 1 may indicate that the resource is unavailable, and a reselection flag value of 0 may indicate that the resource is available, or vice versa. In response to determining that the second UE has reserved the resource, the first UE may reselect a different resource for the transmission, thereby avoiding simultaneous use of the resource by both the first and second UEs (which might have already occurred if they hadn't done so). Therefore, because the first UE reselects the transmission resource, the potential conflict between the first and second UEs is virtual (e.g., hypothetical).

[0042] As mentioned above, virtual collisions may result from multiple UEs attempting to reserve the same resources. Therefore, the number and / or frequency of virtual collisions within a channel can increase with channel congestion (e.g., traffic). Thus, metrics and / or statistics (e.g., average, median, pattern, ratio, etc.) associated with virtual collisions detected by UEs and / or on the channel can provide an indication of congestion on the channel (sideline resource pool). For example, a virtual collision metric can correspond to the total number (e.g., quantity) of virtual collisions detected by a UE on the channel over time or within a certain time period (e.g., a rolling window). That is, for example, a virtual collision metric can correspond to a count of reselection flags set to indicate resource unavailability, as described above. Alternatively or additionally, a virtual collision metric can correspond to the average number of virtual collisions per time period, per communication (e.g., transmission) on the channel, per resource selected for transmission, etc. In some aspects, a virtual collision metric can correspond to a virtual collision rate. In this way, a virtual collision metric can provide an indication of the frequency of virtual collisions over time. In some respects, a virtual collision metric can correspond to the number of potential collisions on a channel, such as the total number of unavailable resources on the channel (e.g., during resource selection for transmission and / or during last-minute reassessment). In other respects, a virtual collision metric can represent the percentage of time a channel is determined to be occupied. Furthermore, in some respects, a virtual collision metric can be determined based on logs of unavailable resources, virtual collisions (e.g., reselection flags), etc. Additionally, as a supplement to or alternative to CBR estimation, a virtual collision metric can be used to estimate channel congestion.

[0043] This application describes a mechanism for optimizing NR sidelink channel access using virtual collision metrics (such as those described above). For example, a UE can perform sidelink transmissions based on virtual collision metrics associated with the availability of resources for transmitting sidelink transmissions. That is, for example, a virtual collision metric can indicate: the number of unavailable resources for sidelink transmissions, the ratio of virtual collisions on the channel for sidelink transmissions, the total number of virtual collisions on that channel, and so on. Based on the virtual collision metric, the UE can determine or adjust channel access parameters such as contention window size, transmit power level, retransmission limits (e.g., maximum number of retransmissions), service profile shaping (e.g., via CR limits), and so on, and the UE can transmit sidelink transmissions based on the adjusted channel access parameters. Furthermore, in some aspects, the UE can use virtual collision metrics to proactively optimize NR sidelink channel access. For example, the UE can determine the virtual collision metric as part of sidelink sensing (e.g., using a reselection flag from a last-minute reassessment). In some aspects, the UE can determine the virtual collision metric based solely on measured sensing without performing transmissions. That is, for example, the UE can choose to measure only resources (e.g., time-frequency resources) and determine a virtual collision metric based on the availability of the selected measurement-only resource, thus avoiding using that measurement-only resource for transmission. Alternatively, the UE can determine the virtual collision metric based on the resources selected for transmission. The mechanisms for optimizing channel access using virtual collision metrics are described in more detail below.

[0044] In some aspects, the UE can select multiple resources from a sidelink resource pool, for example, based on random selection. The sidelink resource pool can refer to a set of time and frequency resources available for sidelink operation. The UE can also request an assessment of the availability of the selected resources. For example, the UE can perform a last-minute reassessment of the selected resources. The UE can also receive an indication of the availability of the selected resources. In some aspects, the UE can receive an indication of availability in response to the assessment, for example, via a reselection flag during the sidelink reassessment process. Furthermore, the UE can perform sidelink transmissions based on a virtual collision metric associated with the indication of the availability of the selected resources.

[0045] In some aspects, the UE can receive an indication that one or more of the selected resources are unavailable. For example, the UE can receive a reselection flag associated with one or more unavailable resources (reserved by other UEs). Furthermore, the indication that one or more of the selected resources are unavailable (e.g., the reselection flag) can correspond to a virtual collision. Therefore, in some aspects, the UE can determine a virtual collision metric based on the indication of one or more unavailable resources. Specifically, the UE can determine the virtual collision metric based on the number of unavailable resources (e.g., the number of virtual collisions). The UE can also store a virtual collision log, which includes records of unavailable resources over time. In some aspects, the UE can also apply filters to the virtual collision log. For example, the UE can apply an average filter and / or the UE can apply a rolling time window to determine the virtual collision metric based on the filtered virtual collision log. In this way, the sensitivity of the virtual collision metric to a specific virtual collision (e.g., channel congestion at a specific time) can be adjusted, thus suppressing the impact of random virtual collisions on communication operations at the UE.

[0046] In some respects, the UE can determine whether a first resource among multiple resources is available based on an indication of the availability of the selected resource. If the UE selects the first resource for transmission, the UE can determine whether to use the first resource to transmit a sidelink transmission based on whether the first resource is available. For example, if the first resource is available, the UE can use the first resource to transmit a sidelink transmission, and if the first resource is unavailable (reserved by another UE), the UE can block transmission in the first resource.

[0047] In some aspects, the selected resources are measurement-only resources. In some aspects, the UE can use the measurement-only resource to determine virtual conflict metrics while preventing transmission using that resource. Therefore, the measurement-only resource can remain available for transmission by other UEs or UEs of other RATs in the sidelink system. For example, in some aspects, selecting resources from the sidelink resource pool may involve selecting a first resource and a second resource from a plurality of resources based on a resource selection trigger, wherein the selected first resource is a measurement-only resource and the selected second resource can be used for a second sidelink transmission. Furthermore, in some aspects, the UE can request an assessment of resource availability by sending a first assessment request for the measurement-only resource (e.g., the first resource) at a first moment and a second assessment request for the second resource at a second moment different from the first moment. Subsequently, the UE can determine whether to use the second resource to perform a sidelink transmission and can prevent the use of the first resource (e.g., the measurement-only resource) to perform a sidelink transmission.

[0048] In some aspects, performing sidelink transmission may involve determining channel access parameters for sidelink transmission based on virtual collision metrics, as described above. Channel access parameters may be associated with transmit power used for sidelink transmission. In some aspects, channel access parameters may be associated with the maximum number of retransmissions. Alternatively or additionally, channel access parameters may be associated with contention window size. Furthermore, in some aspects, channel access parameters may be associated with congestion control parameters such as CR and / or CBR. Furthermore, the UE may determine when to utilize virtual collision metrics to determine or adjust channel access parameters, for example, based on a threshold being met during a virtual collision log recording period, based on a threshold being met based on the number of resources selected for determining the virtual collision metrics, and / or based on a threshold being met based on the virtual collision metrics.

[0049] In some aspects, the UE may perform sidelink operations based on a threshold satisfied by a virtual collision metric. In some aspects, to perform sidelink transmissions, the UE may select a second resource from the sidelink resource pool for sidelink transmissions based on congestion control, and determine whether to use the virtual collision metric for congestion control based on a configuration. This configuration may include an indication indicating whether congestion control using the virtual collision metric is permitted. Alternatively or additionally, the configuration may include an indication indicating whether congestion control using the virtual collision metric is permitted based on at least one of the following: the UE's capabilities, the area associated with the UE (e.g., a geographic region), a time period associated with congestion control, or detection of a RAT different from the UE's Radio Access Technology (RAT).

[0050] In some aspects, the UE can send reports indicating virtual conflict metrics to the base station (BS). Furthermore, the UE can send reports based on a reporting period. For example, the UE can send reports indicating virtual conflict metrics to the BS at regular intervals. Alternatively or concurrently, the UE can send reports on virtual conflict metrics based on report triggers. In some aspects, the UE can receive configuration for reporting virtual conflict metrics from the BS.

[0051] In some respects, the sidelink resource pool is in licensed frequency bands, and in other respects, the sidelink resource pool is in unlicensed frequency bands.

[0052] In some aspects, each resource selected by the UE is a measurement-only resource. For example, in some aspects, the UE can perform measurement-only sensing in a sidelink resource pool. That is, for example, the UE can select measurement-only resources from the sidelink resource pool and obtain the availability of the measurement-only resources. Furthermore, the UE can perform sidelink transmissions based on a virtual collision metric associated with the availability of the measurement-only resources obtained from the measurement-only sensing. To this end, the UE can determine the virtual collision metric without performing transmissions. Furthermore, the UE can perform sidelink transmissions based on the virtual collision metric without using measurement-only resources for transmission. In some aspects, the UE selects resources for exclusive measurement only based on a measurement-only sensing configuration. For example, the UE can receive a measurement-only sensing configuration from the BS. Furthermore, in some aspects, the measurement-only sensing configuration indicates a period, and the UE can select resources based on this period. Alternatively or additionally, the measurement-only sensing configuration may include indications of events associated with at least one of a geographic area, a lost packet delay budget (PDB), or a virtual collision metric threshold. The UE can select resources based on the detection of events included in the measurement-only sensing configuration. In addition, in some aspects, the UE can receive measurement-only sensing configuration at the Media Access Control (MAC) layer.

[0053] Various aspects of this disclosure can provide several benefits. For example, the use of virtual collision metrics can be used for adaptive congestion control. In particular, channel access parameters such as contention window size, transmit power level, retransmission limits (e.g., maximum number of retransmissions), traffic profile shaping (e.g., via CR limits), etc., can be determined and / or adjusted based on virtual collision metrics. As an illustrative example, the contention window size associated with a transmission from the UE can increase as congestion on the channel increases, giving the UE a greater chance of successful transmission. Therefore, adjusting transmission based on channel congestion can improve communication efficiency within the network. Furthermore, using virtual collision metrics to estimate channel congestion can provide more accurate results than estimations determined using CBR-based metrics. Thus, the techniques described herein can provide better channel congestion control, reduce channel access uncertainty, and / or improve communication efficiency within the network. Moreover, the impact of virtual collisions on the UE and / or the channel may be much smaller than that of actual collisions on the channel. That is, for example, identifying conflicts at resources during last-minute evaluation and the UE's reselection of alternative resources for transmission can result in fewer channel interruptions (e.g., interference) compared to simultaneous transmission by the UE and another device using the same resources. Furthermore, virtual conflict metrics can be collected based on resource-only measurements without transmitting data or interrupting the channel and / or network, further reducing the impact on the channel. By utilizing resource-only measurement to collect virtual conflict metrics, the UE can proactively optimize channel access parameters so that when the UE is ready to transmit on the channel, it can transmit based on parameters adjusted for channel congestion, thereby reducing the chance of unsuccessful and / or delayed transmissions.

[0054] Figure 1 A wireless communication network 100 according to some aspects of this disclosure is illustrated. Network 100 may be a 5G network. Network 100 includes multiple base stations (BSs) 105 (labeled 105a, 105b, 105c, 105d, 105e, and 105f, respectively) and other network entities. BS 105 may be a station communicating with UE 115 and may also be referred to as: evolved Node B (eNB), next-generation eNB (gNB), access point, etc. Each BS 105 may provide communication coverage for a specific geographic area. In 3GPP, the term "cell" may refer to that specific geographic coverage area of ​​BS 105 and / or the BS subsystem serving that coverage area, depending on the context in which the term is used.

[0055] BS 105 can provide communication coverage for macrocells or small cells (such as picocells or femtocells), and / or other types of cells. Macrocells generally cover a relatively large geographic area (e.g., a radius of several kilometers) and allow unrestricted access by UEs with service subscriptions to a network provider. Small cells (such as picocells) will generally cover a relatively small geographic area and allow unrestricted access by UEs with service subscriptions to a network provider. Small cells (e.g., femtocells) will also typically cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, provide restricted access by UEs associated with the femtocell (e.g., UEs in a Closed Subscriber Group (CSG), UEs of users in a home, etc.). A BS used for macrocells may be referred to as a macro BS. A BS used for small cells may be referred to as a small cell BS, pico BS, femtocell BS, or home BS. Figure 1 In the examples shown, BS105d and 105e can be conventional macro BSs, while BS105a-105c can be macro BSs with one of three-dimensional (3D), full-dimensional (FD), or massive MIMO capabilities. BS 105a-105c can utilize their higher-dimensional MIMO capabilities to employ 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. BS 105f can be a small cell BS, which can be a home node or a portable access point. BS 105 can support one or more (e.g., two, three, four, etc.) cells.

[0056] Network 100 can support synchronous or asynchronous operation. For synchronous operation, BSs can have similar frame timing, and transmissions from different BSs can be roughly aligned in time. For asynchronous operation, BSs can have different frame timing, and transmissions from different BSs can be out of time.

[0057] UE 115 is distributed throughout the wireless network 100, and each UE 115 can be stationary or mobile. UE 115 can also be referred to as a terminal, mobile station, user unit, station, etc. UE 115 can be a cellular phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, tablet computer, laptop computer, cordless phone, wireless local loop (WLL) station, etc. On one hand, UE 115 can be a device that includes a Universal Integrated Circuit Card (UICC). On the other hand, UE can be a device that does not include a UICC. In some aspects, UE 115 without a UICC can also be referred to as an IoT device or Internet of Things (IoE) device. UE 115a-115d are examples of mobile smartphone-type devices accessing network 100. UE 115 can also be a machine specifically configured for connected communications, including Machine Type Communication (MTC), Enhanced MTC (eMTC), Narrowband IoT (NB-IoT), etc. UE 115e-115h are examples of various machines configured for communication access to network 100. UE 115i-115k are examples of vehicles equipped with wireless communication devices configured for communication access to network 100. UE 115 can communicate with any type of BS (whether macro BS, small cell, etc.). Figure 1 In the diagram, the lightning bolt symbol (e.g., a communication link) indicates radio transmissions between UE 115 and serving BS 105 (which is a BS designated to serve UE 115 on the downlink (DL) and / or uplink (UL), desired transmissions between BSs, backhaul transmissions between BSs, or sidelink transmissions between UE 115.

[0058] In operation, BS 105a-105c can use 3D beamforming and cooperative spatial technologies (e.g., Cooperative Multipoint (CoMP) or Multi-Connectivity) to serve UEs 115a and 115b. Macro BS 105d can perform backhaul communication with BS 105a-105c and the small cell BS 105f. Macro BS 105d can also transmit multicast services subscribed to and received by UEs 115c and 115d. Such multicast services may include mobile TV or streaming video, or may include other services for providing community information, such as weather emergencies or alerts, such as Amber Alerts or Grey Alerts.

[0059] BS 105 can also communicate with the core network. The core network can provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. At least some of the BS 105s (e.g., examples of gNBs or Access Node Controllers (ANCs)) can interface with the core network via backhaul links (e.g., NG-C, NG-U, etc.) and can perform radio configuration and scheduling for communication with UE 115. In various examples, the BS 105s can communicate directly or indirectly (e.g., via the core network) with each other via backhaul links (e.g., X1, X2, etc.), which can be wired or wireless communication links.

[0060] Network 100 can also support mission-critical communication with highly reliable and redundant links for mission-critical devices (e.g., UE 115e, which could be a drone). Redundant communication links with UE 115e can include links from macro BSs 105d and 105e, and links from small cell BS 105f. Other machine-type devices (such as UE 115f (e.g., a thermometer), UE 115g (e.g., a smart meter), and UE 115h (e.g., a wearable device)) can communicate directly with BSs (such as small cell BS 105f and macro BS 105e) via network 100, or communicate in a multi-step configuration with another user equipment relaying its information to the network; for example, UE 115f relays temperature measurement information to smart meter UE 115g, which is then reported to the network via small cell BS 105f. Network 100 can also provide additional network efficiency through dynamic, low-latency TDD / FDD communications (such as V2V, V2X, C-V2X communications between UE 115i, 115j, or 115k and other UE 115, and / or vehicle-to-infrastructure (V2I) communications between UE 115i, 115j, or 115k and BS 105).

[0061] In some implementations, network 100 uses OFDM-based waveforms for communication. OFDM-based systems can divide the system BW into multiple (K) orthogonal subcarriers, which are also commonly referred to as subcarriers, tones, frequency bands, etc. Each subcarrier can be modulated with data. In some cases, the subcarrier spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system BW. The system BW can also be divided into subbands. In other cases, the subcarrier spacing and / or the duration of the time interval (TTI) can be scalable.

[0062] In some respects, BS 105 can assign or schedule transmission resources (e.g., in the form of time-frequency resource blocks (RBs)) for downlink (DL) and uplink (UL) transmissions in network 100. DL refers to the transmission direction from BS 105 to UE 115, while UL refers to the transmission direction from UE 115 to BS 105. Communication can be in the form of radio frames. Radio frames can be divided into multiple subframes or time slots, for example, approximately 10 subframes or time slots. Each time slot can be further divided into micro-time slots. In FDD mode, simultaneous UL and DL transmissions can occur in different frequency bands. For example, each subframe includes UL subframes in the UL band and DL subframes in the DL band. In TDD mode, UL and DL transmissions occur using the same frequency band at different time periods. For example, a subset of subframes in a radio frame (e.g., DL subframes) can be used for DL ​​transmissions, and another subset of subframes in a radio frame (e.g., UL subframes) can be used for UL transmissions.

[0063] DL subframes and UL subframes can be further divided into several regions. For example, each DL or UL subframe can have a predefined region for the transmission of reference signals, control information, and data. Reference signals are predetermined signals that facilitate communication between BS 105 and UE 115. For example, reference signals can have a specific pilot pattern or structure, where pilot tones can span an operating BW or frequency band, and each pilot tone is located at a predefined time and predefined frequency. For example, BS 105 can transmit a cell-specific reference signal (CRS) and / or a channel state information-reference signal (CSI-RS) to enable UE 115 to estimate the DL channel. Similarly, UE 115 can transmit a sounding reference signal (SRS) to enable BS 105 to estimate the UL channel. Control information can include resource allocation and protocol control. Data can include protocol data and / or operational data. In some aspects, BS 105 and UE 115 can communicate using self-contained subframes. Self-contained subframes can include portions for DL ​​communication and portions for UL communication. Self-contained subframes can be DL-centric or UL-centric. DL-centric subframes can include a duration for DL ​​communication that is longer than the duration for UL communication. UL-centric subframes can include a duration for UL communication that is longer than the duration for DL ​​communication.

[0064] In some respects, network 100 may be an NR network deployed on licensed spectrum. BS 105 may transmit synchronization signals (e.g., including primary synchronization signal (PSS) and secondary synchronization signal (SSS)) within network 100 to facilitate synchronization. BS 105 may broadcast system information associated with network 100 (e.g., including primary information block (MIB), residual system information (RMSI), and other system information (OSI)) to facilitate initial network access. In some cases, BS 105 may broadcast PSS, SSS, and / or MIB in the form of synchronization signal blocks (SSB) on the physical broadcast channel (PBCH), and may broadcast RMSI and / or OSI on the physical downlink shared channel (PDSCH).

[0065] In some respects, UE 115 attempting to access network 100 can perform an initial cell search by detecting the PSS from BS 105. The PSS can provide time-slot synchronization and can indicate a physical layer identity value. UE 115 can then receive the SSS. The SSS provides radio frame synchronization and can provide a cell identity value, which can be combined with a physical layer identity value to identify the cell. The PSS and SSS can be located in the center portion of the carrier or at any suitable frequency within the carrier.

[0066] After receiving the PSS and SSS, UE 115 can receive the MIB. The MIB may include system information for initial network access and scheduling information for RMSI and / or OSI. After decoding the MIB, UE 115 can receive the RMSI and / or OSI. The RMSI and / or OSI may include radio resource control (RRC) information related to the Random Access Channel (RACH) procedure, paging, control resource set (CORESET) for monitoring the Physical Downlink Control Channel (PDCCH), Physical UL Control Channel (PUCCH), Physical UL Shared Channel (PUSCH), power control, and SRS.

[0067] After obtaining the MIB, RMSI, and / or OSI, UE 115 can perform a random access procedure to establish a connection with BS 105. In some examples, the random access procedure can be a four-step random access procedure. For example, UE 115 can send a random access preamble, and BS 105 can respond with a random access response. The random access response (RAR) may include a detected random access preamble identifier (ID) corresponding to the random access preamble, timing advance (TA) information, UL grant, temporary cell radio network temporary identifier (C-RNTI), and / or backoff indicator. Upon receiving the random access response, UE 115 can send a connection request to BS 105, and BS 105 can respond with a connection response. The connection response may indicate contention resolution. In some examples, the random access preamble, RAR, connection request, and connection response may be referred to as message 1 (MSG1), message 2 (MSG2), message 3 (MSG3), and message 4 (MSG4), respectively. In some examples, the random access procedure can be a two-step random access procedure, where UE 115 can send the random access preamble and connection request in a single transmission, and BS 105 can respond by sending the random access response and connection response in a single transmission.

[0068] After the connection is established, UE 115 and BS 105 can enter the normal operation phase, during which they can exchange operational data. For example, BS 105 can schedule UE 115 to perform UL and / or DL ​​communication. BS 105 can send UL and / or DL ​​scheduling authorizations to UE 115 via PDCCH. The scheduling authorization can be sent in the form of DL control information (DCI). BS 105 can send DL communication signals (e.g., carrying data) to UE 115 via PDSCH based on the DL scheduling authorization. UE 115 can send UL communication signals to BS 105 via PUSCH and / or PUCCH based on the UL scheduling authorization.

[0069] In some aspects, network 100 can operate on a system BW or a component carrier (CC) BW. Network 100 can divide the system BW into multiple BWPs (e.g., portions). BS 105 can dynamically assign UE 115 to operate on a particular BWP (e.g., a portion of the system BW). The assigned BWP can be referred to as the active BWP. UE 115 can monitor the active BWP to look for signaling information from BS 105. BS 105 can schedule UE 115 to perform UL or DL ​​communication in the active BWP. In some aspects, BS 105 can assign a pair of BWPs within a CC to UE 115 for UL and DL communication. For example, a BWP pair may include one BWP for UL communication and one BWP for DL ​​communication.

[0070] In some aspects, network 100 can operate on a shared channel, which may include a shared frequency band or an unlicensed frequency band. For example, network 100 may be an NR-unlicensed (NR-U) network operating on an unlicensed frequency band. In such aspects, BS 105 and UE 115 may be operated by multiple network operating entities. To avoid collisions, BS 105 and UE 115 may employ an LBT procedure to monitor transmission opportunities (TXOPs) in the shared channel. The wireless communication device may perform LBT in the shared channel. LBT is a channel access scheme that can be used in unlicensed spectrum. When the LBT result is LBT pass (the wireless communication device wins the contention for the wireless medium), the wireless communication device can access the shared medium to transmit and / or receive data. For example, a transmitting node (e.g., BS 105 or UE 115) may perform LBT before transmitting in the channel. When LBT pass, the transmitting node may continue transmitting. When LBT fail, the transmitting node may block transmission in the channel. In the example, LBT may be based on energy detection. For example, when the signal energy measured from the channel is below a threshold, the LBT result is a pass. Conversely, when the signal energy measured from the channel exceeds the threshold, the LBT result is a failure. In another example, LBT can be based on signal detection. For example, when no channel reservation signal (e.g., a predetermined preamble signal) is detected in the channel, the LBT result is a pass. Conversely, when a channel reservation signal is detected in the channel, the LBT result is a failure. TXOP can also be referred to as Channel Occupancy Time (COT).

[0071] Additionally, LBT can be in various modes. LBT modes can be, for example, Category 4 (CAT4) LBT or Category 2 (CAT2) LBT. CAT2 LBT refers to an LBT without a random backoff period. CAT4 LBT refers to an LBT with random backoff and a variable contention window (CW). The serving BS 105 can perform CAT4 LBT to obtain the Contention Time Opportunity (COT) for communication with the UE. Additionally, the BS 105 can, for example, send a COT indication at the beginning of the COT to indicate the duration of the COT and / or one or more subbands in which the COT resides. The serving BS 105 can share the COT with the UE 115. To share the BS 105's COT, the UE can perform CAT2 LBT within the BS 105's COT. During CAT2 LBT, the UE can transmit UL transmissions within the BS 105's COT. The UE 115 can also obtain a COT outside the serving BS 105's COT for UL transmissions by performing CAT4 LBT. In some cases, UE 115 can also share the COT of UE 115 with BS 105. In some cases, CAT4 LBT mode can be referred to as Type 1 LBT, and CAT2 LBT mode can be referred to as Type 2 LBT.

[0072] In some respects, network 100 can provide sidelink communication to allow UE 115 to communicate with another UE 115 without tunneling through BS 105 and / or the core network, such as Figure 2As shown above, sidelink communication can be transmitted on the PSCCH and PSSCH. For example, the PSCCH can carry an SCI, and the PSSCH can carry an SCI and / or sidelink data (e.g., user data). Each PSCCH is associated with a corresponding PSSCH, where the SCI in the PSCCH can carry reservation and / or scheduling information for sidelink data transmission in the associated PSSCH. The SCI can also carry information for reserving future resources (e.g., up to approximately two future PSSCHs for retransmission using HARQ). In some examples, the sidelink transmitting UE 115 can indicate the SCI in two phases. In the first phase SCI, the UE 115 can transmit the SCI in the PSCCH, which carries information for resource allocation and decoding the second phase SCI. The first-stage SCI may include at least one of the following: priority, PSSCH resource allocation, resource reservation period (if enabled), PSSCH DMRS mode (if more than one mode is configured), second-stage SCI format (e.g., the size of the second-stage SCI), amount of resources used for the second-stage SCI, number of PSSCH demodulation reference signal (DMRS) ports, modulation and coding scheme (MCS), etc. In the second-stage SCI, UE 115 may transmit an SCI carrying information for decoding the PSSCH within the PSSCH. The second-stage SCI may include a 1-bit L1 destination identifier (ID), an 8-bit L1 source ID, a HARQ process ID, a new data indicator (NDI), a redundancy version (RV), etc. It should be understood that these are examples, and the first-stage SCI and / or the second-stage SCI may include or indicate additional or different information compared to those examples provided. Sidelink communication can also be transmitted via the Physical Side Link Feedback Control Channel (PSFCH), which indicates acknowledgment (ACK) or negative acknowledgment (NACK) for previously transmitted PSSCH.

[0073] In some respects, a pair of sidelink transmitting UEs 115 and sidelink receiving UEs 115 can communicate with each other using the autonomous mode-2RRA discussed above. For example, the sidelink transmitting UE 115 can continuously sense or monitor resources in the sidelink resource pool. Sensing or monitoring may include decoding the SCI and / or measuring the signal energy in the channel. The sidelink transmitting UE 115 can record the SCI decoding results and signal measurement results. Upon receiving a data packet for transmission, the sidelink transmitting UE 115 can determine a resource selection window and identify candidate resources from the resource selection window based on the sensing results obtained from the sensing window (e.g., decoded SCI and signal measurement results), as will be discussed below. Figures 3A-3BThis is discussed more comprehensively in the following section. Sidelink transmission UE 115 can randomly select resources from the candidate resources and use the selected resources to transmit sidelink transmissions (e.g., including SCI on PSCCH and / or data on PSSCH).

[0074] According to various aspects of this disclosure, the sidelink transmitting UE 115 can determine a virtual collision metric based on the availability of the selected resources during a last-minute reassessment. Specifically, the sidelink transmitting UE 115 can determine whether the resources selected by the sidelink transmitting UE 115 (e.g., based on sensing results) have become unavailable before the sidelink transmitting UE 115 uses one or more of these resources for transmission. That is, for example, the sidelink transmitting UE 115 can determine whether a virtual collision has occurred due to the sidelink transmitting UE 115's selection of the resource and the reservation of the same resource by another wireless communication device (e.g., another UE). The UE 115 can also determine a virtual collision metric based on the identified virtual collisions. For example, the UE 115 can determine the total number of virtual collisions, the ratio of virtual collisions, and / or the frequency, etc., as a virtual collision metric. To this end, the virtual collision metric can provide an indication of the level of traffic (e.g., congestion) on the channel corresponding to the resource. In some aspects, the sidelink transmitting UE 115 can transmit sidelink transmissions based on the virtual collision metric. For example, the sidelink transmitting UE 115 can adjust one or more channel access parameters associated with the sidelink transmission based on a virtual collision metric. In this way, the sidelink transmitting UE 115 can optimize channel access associated with the sidelink transmission based on the channel congestion level indicated by the virtual collision metric, as will be described more fully.

[0075] Figure 2 An example of a wireless communication network 200 providing side-link communication according to various aspects of this disclosure is shown. Network 200 may correspond to a portion of network 100. For the purpose of simplifying the discussion, Figure 2One BS 205 and five UEs 215 (shown as 215a, 215v, 215c, 215d, and 215e) are illustrated, but it will be appreciated that aspects of this disclosure can be scaled to any suitable number of UEs 215 (e.g., about 2, 3, 4, 5, 7, or more) and / or BS 205 (e.g., about 2, 3, or more). BS 205 and UE 215 may be similar to BS 105 and UE 115, respectively. BS 205 and UE 215 may share the same radio frequency band for communication. In some cases, the radio frequency band may be a licensed band. In some cases, the radio frequency band may be an unlicensed band (e.g., in the 5 GHz band). In some cases, the radio frequency band may be the Frequency Range 1 (FR1) band. In some cases, the radio frequency band may be the FR2 band. Typically, the radio frequency band can be at any suitable frequency and can have any suitable bandwidth (e.g., about 5 MHz, about 10 MHz, about 20 MHz, about 80 MHz, about 100 MHz or higher).

[0076] In network 200, some of UEs 215 can communicate with each other in peer-to-peer communication. For example, UE 215a can communicate with UE 215b via sidelink 251, UE 215c can communicate with UE 215d via sidelink 252 and / or with UE 215e via sidelink 254, and UE 215d can communicate with UE 215e via sidelink 255. Sidelinks 251, 252, 254, and 255 are unicast bidirectional links. Some of UEs 215 can also communicate with BS 205 in the UL direction and / or DL ​​direction via communication link 253. For example, UEs 215a, 215b, and 215c are within the coverage area 210 of BS 205 and therefore can communicate with BS 205. UEs 215d and 215e are outside coverage area 210 and therefore may not communicate directly with BS 205. In some cases, UE 215c may operate as a relay for UE 215d to reach BS 205. In some aspects, some UEs 215 are associated with a vehicle (e.g., similar to UE 115i-k), and communication on sidelinks 251 and / or 252 may be C-V2X communication. C-V2X communication may refer to communication between the vehicle and any other wireless communication device in the cellular network.

[0077] Discussing each other in relation to each other Figure 3A and 3B This demonstrates autonomous side-link sensing using mode-2RRA. Figure 3AThis is a sequence diagram illustrating an autonomous side-link sensing method 300 according to some aspects of this disclosure. Method 300 can be implemented by UE 215. As shown, method 300 includes a plurality of enumerated actions, but aspects of method 300 may include additional actions before, after, and between the enumerated actions. In some aspects, one or more of the enumerated actions may be omitted or performed in a different order.

[0078] Autonomous side-link sensing can be implemented at UE 215 between MAC layer 302 and PHY layer 304. As shown in the figure, at action 310, PHY layer 304 in the side-link resource pool (e.g., Figure 3B Sensing is performed within the sidelink resource pool 350. The sidelink resource pool can refer to a set of time and frequency resources available for sidelink operation. For example, the PHY layer 304 can continuously sense or monitor resources in the sidelink resource pool (e.g., ...). Figure 3B (Resource 352). Sensing or monitoring may include decoding the SCI and / or measuring the signal energy in the channel. For SCI decoding, PHY layer 304 can blindly decode the SCI from the PSCCH of each resource. If decoding is successful, PHY layer 304 can record the decoded SCI. For signal measurement, PHY layer 304 can receive signals from each resource and calculate the Reference Received Power (RSRP) and / or Received Signal Strength Indicator (RSSI) for each resource. PHY layer 304 can also record the signal measurement results.

[0079] At action 312, MAC layer 302 sends a resource selection trigger to PHY layer 304 (e.g., Figure 3B Resource selection trigger 346). In some respects, MAC layer 302 may send a resource selection trigger based on the generation and readiness of MAC packet data units (PDUs) for transmission.

[0080] At action 314, in response to a resource selection trigger, PHY layer 304 identifies candidate resources from the resource pool based on the sensing results. In this regard, PHY layer 304 can determine the sensing window based on the resource selection trigger (e.g., Figure 3B The sensing window 342) and the resource selection window (e.g., Figure 3B The resource selection window 344). The PHY layer 304 can identify candidate resources from the resource selection window based on past sensing results obtained in the sensing window (e.g., decoded SCI and / or signal measurement results). Resource selection triggering, sensing window, and resource selection window in Figure 3B As shown in the image.

[0081] Figure 3BAn autonomous side-link sensing scheme 340 according to some aspects of this disclosure is illustrated. Scheme 340 can be adopted by UE 215 or any other UE (such as UE 115 and 215). Figure 3B In the diagram, the x-axis represents time in some arbitrary units, and the y-axis represents frequency in some arbitrary units.

[0082] In scheme 340, UE 215 is pre-configured with a sidelink resource pool 350. The sidelink resource pool 350 may span a frequency bandwidth within a licensed frequency band. The sidelink resource pool 350 may include multiple time-frequency resources 352. Each resource 352 may include a specific number of symbols (e.g., OFDM symbols) in time and a specific number of frequency subcarriers in frequency. In some aspects, resources 352 may be in units of RBs (e.g., including 12 consecutive subcarriers in frequency and the duration of a time slot or any suitable duration). Figure 3B The diagram illustrates a sidelink resource pool 350 within a specific time period. Typically, a sidelink resource pool may include time-frequency resources on consecutive time slots (e.g., consecutive time periods) and / or time-spaced time slots (e.g., non-consecutive time periods).

[0083] exist Figure 3B In the example shown, MAC layer 302 can generate a MAC PDU at time slot n and can also generate a resource selection trigger 346 at time slot n. Upon receiving the resource selection trigger 346, PHY layer 304 can, based on including T proc,0 T proc,1 T0, T1, T2 and T2 min The parameter set, relative to the time of resource selection trigger 346, defines the sensing window 342 and the resource selection window 344. For example, the PHY layer 304 can determine the start of the sensing window 342 based on the T0 duration before resource selection trigger 346, and can determine the start of the sensing window 342 based on the T0 duration before resource selection trigger 346. proc,0 The duration determines the end of sensing window 342. As shown in the figure, sensing window 342 begins at the start of duration T0 and ends at T... proc,0 The duration ends at the beginning of the duration. PHY layer 304 can determine the start of resource selection window 344 based on the T1 duration after resource selection trigger 346, and can determine the end of resource selection window 344 based on the T2 duration after resource selection trigger 346. The T1 duration can have parameters T... proc,1 A limited upper limit (e.g., 0≤T1≤T) proc,1 The duration of T2 can be determined to satisfy a certain packet delay budget (PDB), and can have a duration determined by T2. min A lower bound (e.g., T2)min ≤T2≤PDB). As shown in the figure, the resource selection window 344 starts at the end of duration T1 and ends at the end of duration T2. ​​In some aspects, the PHY layer 304 can be pre-configured with some of these parameters (e.g., T...). proc,0 T proc,1 In some respects, the PHY layer 304 can receive some of these parameters (e.g., T1, T2, T3) from an upper layer (e.g., the RRC layer). min ).although Figure 3B A resource selection window 344 is shown that includes 16 resources, but it should be understood that in other examples, the resource selection window may include fewer resources (e.g., about 4, 5, 6, 8 or 10) or more resources (e.g., 17, 18, 19, 20, 24, 32 or more).

[0084] PHY layer 304 can identify candidate resources 352 within resource selection window 344 by examining or analyzing sensing results obtained within sensing window 342. That is, PHY layer 304 can use past sensing results to predict the future use of resources 352 in resource selection window 344. PHY layer 304 can use a combination of SCI decoding, signal measurement results, and / or priority information to identify candidate resources. In some aspects, PHY layer 304 can exclude resources 352 that are reserved in resource selection window 344 (e.g., based on SCI decoding and / or prediction in sensing window 342). PHY layer 304 can exclude resources 352 in resource selection window 344 that are intended for transmissions with a higher service priority than UE 215 (e.g., based on SCI decoding and / or prediction in sensing window 342). PHY layer 304 can exclude resources 352 in resource selection window 344 based on signal measurements (e.g., RSRP and / or RSSI) within sensing window 342 that are above a certain signal threshold and a predicted resource usage pattern. PHY layer 304 can perform resource filtering or exclusion in any suitable order, through SCI decoding, prioritization, and / or signal measurements in resource selection window 344. If the remaining candidate resources 352 in resource selection window 344 are less than 20% of the total resources in resource selection window 344, PHY layer 304 can increase the signal threshold and repeat resource filtering or exclusion until the candidate resources 352 in resource selection window 344 are approximately 20% of the total resources 352 in resource selection window 344. Figure 3B In the resource selection window 344, candidate resources (available resources) 352 are displayed as empty filled boxes. Unavailable resources 352 are displayed as pattern filled boxes.

[0085] return Figure 3AAt action 316, PHY layer 304 sends an indication of the identified candidate resource 352 (e.g., Figure 3B The resource selection window 344 shown contains an empty fill box containing a candidate resource report. This report can indicate the time and frequency location information of the candidate resources.

[0086] At action 318, upon receiving a candidate resource report, MAC layer 302 selects one or more resources from the candidate resources. For example, MAC layer 302 may randomly select a first resource from the candidate resources for transmitting the MAC PDU. As an example, if the report includes a list of N candidate resources, MAC layer 302 may draw a random number between 1 and N (e.g., k) and select the k-th candidate resource. In some cases, UE 215 may apply HARQ to the transmission of a transport block (TB) (carrying a MAC PDU) and may retransmit the same TB if a NACK is received from the corresponding receiving UE or if an ACK for that transmission is not received. Therefore, MAC layer 302 may also randomly select a second resource from the candidate resources by drawing another random number between 1 and N, for example, for potential retransmission of the MAC PDU. Figure 3B An example of resource selection is shown.

[0087] refer to Figure 3B The MAC layer 302 can randomly select a first resource 352a (shown by a black circle) from the candidate resources for initial transmission, and can randomly select a second resource 352b (shown by a black circle) from the candidate resources for retransmission. In some cases, the MAC layer 302 can select the second resource 352b for retransmission, such that the first resource 352a and the second resource 352b are spaced apart by a duration T4. In some aspects, the T4 duration can be less than approximately 32 time slots or any other suitable duration. In some aspects, the T4 duration can have a predetermined or pre-configured lower limit and / or upper limit.

[0088] refer to Figure 3A At action 320, the MAC layer 302 sends a resource reassessment request to the PHY layer 304 (e.g., Figure 3B Resource reassessment request 348). A resource reassessment request may request the PHY layer 304 to report the updated available resources at that moment, in order to re-examine the previously selected resources (e.g., Figure 3B Whether resources 352a and 352b are still available. In some cases, MAC layer 302 may slightly delay the use of the selected first resource (e.g., Figure 3BResource reassessment requests are sent before the actual time (e.g., 1 symbol, 2 symbols, 3 symbols, 4 symbols, or time slot) of the actual time the MAC PDU is sent. Therefore, resource reassessment requests can also be referred to as "last-minute reassessment".

[0089] refer to Figure 3B The MAC layer 302 sends a resource reassessment request 348 at a time T3 before the actual transmission time of the selected first resource 352a. In some respects, the T3 duration may have a predetermined or pre-configured lower and / or upper limit.

[0090] refer to Figure 3A At action 322, in response to the resource re-evaluation request, PHY layer 304 sends an updated resource report to MAC layer 302. PHY layer 304 can identify resources in resource selection window 344 that are still available at the time the resource re-evaluation request was received. PHY layer 304 can use a mechanism substantially similar to that discussed at action 314 to identify available resources (candidate resources) at that time. If the first resource previously selected by MAC layer 302 (e.g., resource 352a) is no longer available, PHY layer 304 can indicate an indication in the report. For example, the report may include a reselection flag for the first resource being set to 1. Similarly, if the second resource previously selected by MAC layer 302 (e.g., resource 352b) is no longer available, PHY layer 304 can indicate an indication in the report. For example, the report may include a reselection flag for the second resource being set to 1.

[0091] If the first resource is no longer available, MAC layer 302 may, at action 324, reselect another resource from the candidate resources indicated in the updated candidate resource report, and may repeat actions 320 and 322 at a later time to perform another last-minute resource re-evaluation on the newly selected resource. Otherwise, at action 326, PHY layer 304 may use the selected first resource to send a MAC PDU to another sidelink UE (e.g., UE 115 and / or 215).

[0092] Similarly, if the second resource (which will be used for retransmission) is no longer available, MAC layer 302 can reselect another resource from the candidate resources indicated in the updated candidate resource report at action 324. MAC layer 302 can also request PHY layer 304 to perform a last-minute resource reassessment of the resource to be used for retransmission.

[0093] Figure 4 An autonomous side-link sensing scheme 400 according to some aspects of this disclosure is shown, and specifically, Figure 4An example of a virtual conflict is shown. Scheme 400 can be adopted by UE 215 or any other UE (such as UE 115 and 215). Figure 4 In the diagram, the x-axis represents time in some arbitrary units, and the y-axis represents frequency in some arbitrary units.

[0094] In scheme 400, UE 215 is pre-configured with a sidelink resource pool 450. The sidelink resource pool 450 can span a frequency bandwidth within an unlicensed or shared frequency band. The sidelink resource pool 450 can be similar to sidelink resource pool 350 and uses the same... Figure 3B The same resource pool structure is illustrated in the figure. As shown, the side link resource pool 450 can include multiple time-frequency resources 452, which can be similar to... Figure 3B The time-frequency resource 352. Each resource 452 may include a specific number of symbols in time (e.g., OFDM symbols) and a specific number of frequency subcarriers in frequency. In some aspects, the resource 452 may be in units of RBs (e.g., including 12 consecutive subcarriers in frequency and the duration of the time slot or any suitable duration). Figure 4 A sidelink resource pool 450 is shown for a specific time period. Typically, a sidelink resource pool may include time-frequency resources 452 on consecutive time slots (e.g., consecutive time periods) and / or time-spaced time slots (e.g., non-consecutive time periods).

[0095] exist Figure 4 In the example shown, MAC layer 302 can generate resource selection trigger 446 at time slot n. Upon receiving resource selection trigger 446, PHY layer 304 can, based on T... proc,0 T proc,1 T0, T1, T2 and T2 min The parameter set, relative to the time of resource selection trigger 446, defines the sensing window 442 and the resource selection window 444, as referenced above. Figure 3B A general description. Although Figure 4 The resource selection window 444 shown includes 16 resources, but it should be understood that in other examples, the resource selection window may include fewer resources (e.g., about 4, 5, 6, 8 or 10) or more resources (e.g., 17, 18, 19, 20, 24, 32 or more).

[0096] PHY layer 304 can identify candidate resources 452 within resource selection window 444 by examining or analyzing sensing results obtained within sensing window 442. That is, PHY layer 304 can use past sensing results to predict the future use of resources 452 in resource selection window 444, as referenced above. Figure 3A -B roughly describes it. In Figure 4 In the resource selection window 444, candidate resources (available resources) 452 are displayed as empty filled boxes. Unavailable resources 452 are displayed as pattern filled boxes.

[0097] exist Figure 4 In the example shown, UE 215 selects a first resource 452a (indicated by a black circle) at MAC 302. For example, MAC 302 may randomly select the first resource 452a from candidate resources. However, in some cases, the resource selected (e.g., reserved) by UE 215 may be preempted or become unavailable before UE 215 performs transmission of the crosslink transmission using the selected resource. That is, a virtual collision may occur at a resource selected by UE 215 and reserved by another wireless communication device (e.g., another UE).

[0098] For example, although the selected resource may appear available for transmissions performed by UE 215 based on past sensing results, another UE may have previously reserved resource 452, making it unavailable for use by UE 215. In some cases, for example, the UE can... proc,0 The reservation 460 for a specific resource 452 (such as resource 452a) is transmitted (e.g., via SCI) during a duration (e.g., the time between the end of sensing window 442 and resource selection trigger 446 at time slot n). Therefore, because UE 215 can select the resource 452 for transmission based on candidate resources identified as available within sensing window 442, sensing window 442 is defined by the time period preceding reservation 460 (e.g., the T0 duration preceding resource selection trigger 446 and T...). proc,0 The duration is defined, so UE 215 can identify resource 452a as available. After identifying resource 452a as available, UE 215 can select resource 452a for transmission, even if a reservation 460 has already been sent by another UE when resource selection triggers 446 (e.g., slot n). As a result, UE 215 can determine that a virtual collision has occurred at resource 452a during a last-minute reassessment of resource 452a (e.g., in response to a resource reassessment request 448). More specifically, UE 215 can detect reservation 460 based on the last-minute reassessment (e.g., via SCI decoding). Specifically, PHY 304 can sense reservation 460 during the last-minute reassessment, and in response to determining that resource 452a is unavailable due to reservation 460, PHY 304 can set a reselection flag. MAC 302 can receive the reselection flag indicating that resource 452a is unavailable and can reselect a different resource for transmission. For example, MAC 302 can reselect resources from the resources included in the updated resource report, as referenced above. Figure 3A As described in actions 322 and 324. Therefore, UE 215 can reschedule the transmission to alternative resource 452.

[0099] In some cases, the reselection of resources used for transmission and / or retransmission can lead to an additional last-minute reassessment by UE 215, such as Figure 5 As shown in the image. Figure 5 A side-link transmission scenario 500 is illustrated according to some aspects of this disclosure. Figure 5 In this context, the x-axis represents time in arbitrary units. Furthermore, resources 552a-c can be similar to resources 352 and / or 452 described herein, resource selection trigger 546a can be similar to resource selection trigger 346 and / or 446 described herein, and resource re-evaluation triggers 548a-c can be similar to resource re-evaluation triggers 348 and / or 448 described herein. Additionally, UE 215 can adopt the approach described in the reference above. Figure 3A and 3B The discussion covers similar resource selection and last-minute reassessment techniques.

[0100] As shown in the figure, at time slot n, UE 215 (e.g., the first UE) may reserve the first resource 552a at time slot n1 in response to the first resource selection trigger 546. At time T3 before time slot n1 corresponding to the first resource 552a, UE 215 may perform a first resource reassessment in response to the first resource reassessment trigger 548a. That is, for example, UE 215 may perform a last-minute reassessment of the first resource 552a. UE 215 may determine, based on the last-minute reassessment, that the first resource 552a is unavailable for transmissions performed by UE 215. Specifically, UE 215 may determine that the first resource 552a has been reserved by another UE (e.g., the second UE) on the same side of the hop link system or another system or another RAT. To this end, UE 215 may identify the second UE's reservation 560a of the same first resource 552a selected by UE 215. For example, the second UE may send an SCI including the reservation 560a. For clarity, earlier resource selections for UE 215 are indicated by diamond-filled boxes, while resources reserved by a second UE (e.g., via SCI) are indicated by vertical stripe-filled boxes. (As in...) Figure 5 As can be seen, the first resource 552a is selected by UE 215 (diamond-shaped fill box) and reserved by the second UE (vertical stripe fill box). Although the diamond-shaped fill box and the vertical stripe fill box are shown as occupying different portions of the first resource 552a, the selection and / or reservation are for the entire first resource 552a.

[0101] As described above, UE 215 can identify a virtual conflict at MAC 302 between UE 215's selection and the reservation 560a of the second UE at the first resource 552a. That is, for example, MAC 302 can receive a reselection flag associated with the first resource 552a and set by PHY 304. For example, PHY 304 can set the reselection flag to a value of 1 to indicate that the first resource 552a is unavailable (reserved by the second UE). In response to the reselection flag (set to a value of 1), UE 215 can reselect (e.g., reschedule) the transmission to the second resource 552b. Specifically, UE 215 can reselect the second resource 552b based on an updated resource report, as referenced above. Figure 3A As described in actions 322 and 324.

[0102] As described above similarly to the reassessment of the first resource, UE 215 may perform a second resource reassessment (e.g., a last-minute reassessment) at time T3 before the time slot n2 corresponding to the second resource 552b, in response to the second resource reassessment trigger 548b. Based on this last-minute reassessment, UE 215 can identify a virtual conflict at the second resource 552b between the selection made by UE 215 and the reservation 560b made by another UE (e.g., a second UE or a third UE) (e.g., MAC 302 can receive a reselection flag indicating that resource 552b is unavailable). Therefore, UE 215 can reschedule the transmission again. More specifically, UE 215 may select the third resource 552c to perform the transmission.

[0103] At time T3 before slot n3 corresponding to third resource 552c, UE 215 may perform a third resource reassessment (e.g., last-minute reassessment) in response to third resource reassessment trigger 548c. Based on this last-minute reassessment, UE 215 can determine that third resource 552c is available for transmission. That is, for example, UE 215 can determine that a collision between UE 215 and another device at third resource 552c may not occur. Therefore, UE 215 can use third resource 552c to perform transmission (e.g., sidelink transmission). Thus, in the example shown, UE 215 performs transmission with a delay (e.g., corresponding to duration (slot n3) - (slot n)) of two resource reselections caused by two virtual collisions (e.g., at first resource 552a and second resource 552b, respectively).

[0104] therefore, Figure 5Illustrative examples are provided to illustrate the impact of channel traffic (e.g., channel congestion) on the communication efficiency of UE 215. Specifically, for example, the virtual collisions shown (e.g., at first resource 552a and second resource 552b respectively) are caused by channel usage (e.g., traffic) by other devices and may result in delays in transmissions to UE 215. Therefore, Figure 5 This can be shown to indicate that as traffic on the channel increases, the latency of transmissions to UE 215 may increase. Specifically, Figure 5 The diagram illustrates how virtual collisions can lead to rescheduled transmissions, and how, with increased channel traffic, virtual collisions and the resulting delays associated with rescheduled transmissions can also increase. Therefore, the quantity and / or frequency of virtual collisions (e.g., frequency and / or ratio) can serve as an indicator of the level of traffic congestion in the channel or sidelink resource pool. For example, if UE 215 detects a high number of virtual collisions over a short period, UE 215 can recognize that the channel may be congested. Conversely, if UE 215 detects a small number of virtual collisions over a long period, UE 215 can recognize that the channel may not be congested. Therefore, UE 215 can determine the level of congestion in the channel by collecting virtual collision metrics (e.g., statistics) regarding virtual collisions. In some cases, virtual collision metrics may additionally or alternatively indicate the total quantity or frequency of virtual collisions. In some aspects, to obtain an accurate view of the level of traffic congestion, UE 215 may also use measurement-only sensing to monitor virtual collisions, rather than relying on when the UE has data for transmission, as will be discussed more fully below.

[0105] In some respects, UE 215 can utilize virtual conflict metrics to adapt to channel congestion and reduce transmission delay. As an illustrative example, UE 215 can adjust channel access parameters based on virtual conflict metrics, such as contention window size, transmit power level, retransmission limits (e.g., maximum number of retransmissions), service profile shaping (e.g., via CR limits), and so on. Contention window size (e.g., contention window duration) can refer to the duration in which UE 215 can select sidelink resources. For example, in some respects, UE 215 can apply an effective contention window to the RRA mode-2 sidelink sensing process to suppress congestion. Figure 6A A sidelink resource selection scheme 620 utilizing a contention window is illustrated according to various aspects of this disclosure. Scheme 620 can be implemented by UE 215 as part of a sidelink resource selection process, for example, corresponding to the above reference. Figures 3A-3B The discussion covers method 300 and action 318. In... Figure 6A In the diagram, the x-axis represents time in some arbitrary units, and the y-axis represents frequency in some arbitrary units.

[0106] In scheme 620, UE 215 (at PHY 304) can, for example, in response to a resource selection trigger from MAC 302, identify candidate resources from resources 632 in resource selection window 630 (e.g., resource selection window 344). In the illustrated example, PHY 304 identifies resources 632A, 632B, 632C, 632D, and 632E as candidates (available resources not reserved by another device or UE), for example, based on sensing. PHY 304 can report candidate resources 632A-E to MAC 302. MAC 302 can perform additional filtering on the set of available resources 632A-E, for example, to suppress congestion. In this regard, MAC 302 can apply contention window 640 to resource selection window 630, and instead of selecting resource 632 from candidate resources 632A-E reported by PHY 304, MAC 302 can select a resource from candidate resources 632 (e.g., resource C or resource D) within contention window 640.

[0107] As can be observed, contention window 640 can limit or reduce the number of candidate resources 632 from which UE 215 can select for transmission. Therefore, adjusting the contention window size can affect the duration for which UE 215 is allowed to attempt to access the channel for transmission, as further described below, and can thus control congestion in the channel.

[0108] Figure 6B A graph 600 shows the contention window size dynamically adjusted over time. In some aspects, increasing the contention window size (e.g., the duration 642 of contention window 640) can increase the number of candidate resources from which UE 215 can select for transmission, and therefore UE 215 may have increased opportunities to access channels for transmission. Therefore, increasing the contention window size associated with UE 215 can reduce transmission delay at UE 215, which may be caused by virtual collisions. Therefore, in some aspects, UE 215 can increase the contention window size for transmissions from UE 215 in response to failed channel access at UE 215. Failed channel access can refer to failure to receive an ACK (e.g., HARQ ACK) for a sidelink transmission (e.g., PSSCH transmission), receiving a NACK (e.g., HARQ NACK) for a sidelink transmission, LBT failure, and / or detection of virtual collisions. Using virtual collisions as a metric for adjusting the contention window size allows UE 215 to proactively adapt to channel congestion before actual transmission failures or actual collisions occur.

[0109] For example, time S1 may correspond to the first failed channel access attempt of UE 215, which could be due to virtual collisions, failed LBT attempts, etc. As shown, after the first failed channel access attempt at S1 (e.g., within segment 602), UE 215 increases the contention window size (e.g., via MAC layer 302). In some aspects, MAC layer 302 may increase the contention window size in a doubling manner based on a virtual collision metric indicating the increased number and / or frequency of failed channel access attempts by UE 215. For example, after the first failed channel access attempt (e.g., at time S1), MAC 302 may double the contention window size.

[0110] UE 215 can also be configured to reduce the contention window size based on successful transmissions and / or missing channel access attempts. For example, UE 215 can linearly reduce the contention window size based on successful channel access attempts. That is, for example, MAC layer 302 can progressively reduce the contention window size by a consistent amount relative to a certain time interval and / or relative to each successful channel access attempt. By reducing the contention window size, UE 215 can increase the probability of successful channel access for other devices attempting to access the channel. Therefore, UE 215 can share channel access more fairly.

[0111] For example, in the graph 600 shown, after increasing the contention window size in response to a failed channel attempt at time S1, UE 215 can successfully access the channel. Therefore, UE 215 can decrease the contention window size (e.g., within time period 604) until UE 215 detects a second channel access failure at time S2. As the contention window size associated with UE 215 decreases, channel access attempts by other UEs and / or RATs attempting to access the channel increase.

[0112] Graph 600 also illustrates that UE 215 can continuously adjust the contention window size based on the most recent channel access attempt. For example, in response to a second channel access failure at time S2, UE 215 can increase the contention window size again (e.g., within time period 606). Subsequently, UE 215 can decrease the contention window size (e.g., within time period 608). In response to a third channel access failure at time S3, UE 215 can increase the contention window size again (e.g., within time period 610), and UE 215 can then decrease the contention window size after a successful channel access (e.g., within time period 612).

[0113] While graph 600 illustrates UE 215's response to each of the first, second, and third failed channel access attempts (e.g., at times S1, S2, and S3, respectively), aspects are not limited thereto. In some aspects, for example, UE 215 may filter virtual conflict metrics and / or failed channel access attempts, and may adjust channel access parameters (e.g., contention window size) based on the results of the filtering. For example, UE 215 may consider virtual conflict metrics occurring at a specific frequency within a rolling time window, and / or may average virtual conflict metrics over a specific time period to determine how to adjust channel access parameters.

[0114] Furthermore, in some aspects, the number of channel access attempts corresponding to attempts to perform transmissions and / or the number of last-minute reassessments of the resources used for transmission by UE 215 may be insufficient to determine a relatively reliable virtual conflict metric. For example, in some aspects, UE 215 may determine the virtual conflict metric based on the availability of selected resources. As mentioned above, the selected resources may correspond to resources selected for transmission (e.g., transmission resources), and UE 215 may determine availability based on last-minute reassessments of the selected resources. Therefore, the number of resources used to determine the virtual conflict metric (e.g., the number of virtual conflict metric samples) may depend on the number of transmissions performed at UE 215. For this purpose, relatively few transmissions may result in virtual conflict metrics determined based on fewer samples, while larger transmissions may result in virtual conflict metrics determined based on a larger number of samples. In some aspects, the fewer samples used to determine the virtual conflict metric, the more susceptible the virtual conflict metric is to randomness (e.g., sample outliers). Conversely, increasing the number of samples can improve the reliability of the virtual conflict metric. Therefore, in some respects, UE 215 can be configured to determine virtual collision metrics and / or perform sidelink transmissions based on the number of resources used to meet a predetermined threshold. In this way, the sensitivity of virtual collision metrics to randomness can be adjusted.

[0115] Alternatively or concurrently, in some aspects, UE 215 may use only the measured resource to determine the virtual conflict metric. That is, for example, UE 215 may select and determine resource availability, for example, by utilizing the same sensing and last-minute reassessment process discussed above. However, regardless of resource availability, UE 215 will prevent the use of the only measured resource for transmissions. In this way, UE 215 can increase the number of samples used to determine the virtual conflict metric over a duration, rather than relying on the number of transmissions occurring at UE 215. As described in more detail below, UE 215 may exclusively use the only measured resource to determine the virtual conflict metric (e.g., UE 215 may perform actions such as...). Figure 7As shown, the measurement-only sensing) and / or UE215 can use the measurement-only resources together with the transmission resources to determine the virtual collision metric (such as... Figure 8 (As shown).

[0116] Figure 7 This is a sequence diagram illustrating some aspects of a virtual collision-based channel access method 700 associated with a virtual collision metric determined based solely on measured resources, according to this disclosure. Method 700 can be used by UE 215, for example, by utilizing the following... Figure 12 The components discussed in UE 1200 are used for implementation. As shown, method 700 includes a plurality of enumerated actions, but aspects of method 700 may include additional actions before, after, and between the enumerated actions. In some aspects, one or more of the enumerated actions may be omitted or performed in a different order. At a high level, in method 700, UE 215 may perform measurement-only sensing (e.g., reusing RRA mode-2 side link sensing) to collect virtual collision statistics and utilize the virtual collision statistics as a metric for channel access optimization.

[0117] Generally speaking, method 700 includes features similar to method 300 in many respects. For example, actions 712, 714, 716, and 718 are similar to actions 310, 312, 314, and 316, respectively. Therefore, for the sake of brevity, the details of these steps will not be repeated here.

[0118] At action 710, MAC layer 302 may send a sensing request to PHY 304. The sensing request may be associated with measurement-only sensing. In some aspects, MAC layer 302 may be configured by Layer 3 (L3) of UE 215 to perform measurement-only sensing. Layer L3 may refer to an upper layer, such as the network layer at UE 215. For example, L3 may configure MAC layer 302 to perform measurement-only sensing periodically, semi-periodically, event-triggered, or a combination thereof. Accordingly, MAC 302 may send a sensing request to PHY 304 based on the L3 configuration. In some aspects, event triggering may include UE 215 entering a specific geographic area, such as entering or leaving coverage area 210. For example, UE 215 may be equipped with GPS, which can provide indication of when UE 215 enters or leaves a specific area. Alternatively or additionally, MAC layer 302 may be triggered to send a sensing request if the packet delay budget (PDB) at UE 215 fails to meet a predefined (e.g., threshold) number of times. In addition, in some respects, event triggering can be based on the number of retransmissions (e.g., HARQ retransmissions) (e.g., the average number of retransmissions over a time window) exceeding a threshold and / or the average number of virtual collisions within a time window exceeding a threshold.

[0119] At action 712, PHY layer 304 performs sensing in the side traversal resource pool. PHY layer 304 can continuously sense or monitor resources in the side traversal resource pool, and / or PHY 304 can perform sensing in the side traversal resource pool in response to a sensing request (e.g., action 710). The sensing operation can include similar to Figure 3A The SCI decoding of the sensing operation at action 310. PHY layer 304 may not be aware that the sensing request is associated with only measurement sensing.

[0120] At action 714, MAC layer 302 sends a resource selection trigger to PHY layer 304. In some aspects, MAC layer 302 may send the resource selection trigger based on the generation and readiness of MAC Packet Data Units (PDUs) for transmission.

[0121] At action 716, PHY layer 304 identifies candidate resources. PHY layer 304 can identify candidate resources based on sensing (e.g., at action 712), and can also generate a candidate resource report based on the identified candidate resources. Therefore, at action 718, PHY layer 304 can send the candidate resource report to MAC layer 302. This report can indicate the time and frequency location information of the candidate resources.

[0122] At action 720, MAC layer 302 selects one or more measurement-only resources from the candidate resources within the received candidate resource report. For example, MAC layer 302 may randomly select a measurement-only resource from the candidate resources to determine a virtual conflict metric. In some cases, such as UE 215, the selected measurement-only resource may be used to determine whether a virtual conflict is associated with that resource, as described in more detail below. To select a measurement-only resource, if the report includes a list of N candidate resources, MAC layer 302 may draw a random number between 1 and N (e.g., k) and select, for example, the kth candidate resource. Furthermore, in some cases, such as MAC layer 302, a second resource may be randomly selected from the candidate resources by drawing another random number between 1 and N. MAC layer 302 may also use the second resource to determine a virtual conflict metric. Alternatively or additionally, MAC layer 302 may select multiple measurement-only resources, and each of the selected measurement-only resources may be used to determine a virtual conflict metric. In some aspects, for example, UE 215 can be configured with a maximum number of measurement-only resources, and MAC layer 302 can select the maximum number of measurement-only resources from the candidate resources, and / or MAC layer 302 can select each candidate resource from the available candidate resources as a measurement-only resource.

[0123] At action 722, MAC layer 302 sends a measurement-only resource reassessment request to PHY layer 304. The measurement-only resource reassessment request may request PHY layer 304 to report updated available resources at that moment, to re-check whether the previously selected measurement-only resource is still available. The measurement-only resource reassessment request can be substantially similar to... Figure 3A The resource reassessment request is located at action 320. Similarly, the PHY layer 304 may not be aware that the measurement-only resource reassessment request is associated with measurement-only sensing. In some cases, the MAC layer 302 may send the measurement-only resource reassessment request slightly before the slot boundary of the selected measurement-only resource (e.g., 1 symbol, 2 symbols, 3 symbols, 4 symbols, or slot). For example, the MAC layer 302 may send the measurement-only resource reassessment request at a duration of T3 before the slot boundary of the selected measurement-only resource. Therefore, the resource reassessment request can also be referred to as a "last-minute reassessment" of the measurement-only resource. Furthermore, in some cases, the MAC layer 302 may send a measurement-only resource reassessment request to the PHY layer 304 for each of the selected measurement-only resources. Specifically, the MAC layer 302 may send the corresponding measurement-only resource reassessment request to the PHY layer 304 slightly before the slot boundary of the corresponding measurement-only resource for each of the selected measurement-only resources. Alternatively, MAC layer 302 may send a single measurement-only resource re-evaluation request to PHY layer 304, and PHY layer 304 may re-evaluate each measurement-only resource based on the same measurement-only resource re-evaluation request.

[0124] At action 724, based on the resource reassessment request (measured only), PHY layer 304 sends an updated resource report to MAC layer 302. In the updated resource report, PHY layer 304 can identify resources that were still available at the time the resource reassessment request was received (without reservations from another UE), as described above. Figure 3A Action 322 is described similarly. If the previously selected measurement-only resource in MAC layer 302 is no longer available, PHY layer 304 may include an indication in the report. For example, the report may include a reselection flag set to 1 for the unavailable measurement-only resource. Furthermore, PHY layer 304 may provide an indication of the availability of each of the selected measurement-only resources. For example, PHY layer 304 may determine, for each measurement-only resource, whether to set the corresponding reselection flag based on the availability of the measurement-only resource.

[0125] At action 726, MAC layer 302 may determine a virtual conflict metric based on an updated resource report received from PHY layer 304. For example, a reselection flag within the updated resource report may correspond to a virtual conflict at a specific resource. Therefore, MAC layer 302 may determine a virtual conflict metric based on the reselection flag associated with the selected measurement-only resource. Specifically, MAC layer 302 may determine a virtual conflict metric based on the total number of virtual conflicts identified within the updated resource report (e.g., the number of unavailable measurement-only resources). Alternatively or additionally, MAC layer 302 may determine a virtual conflict metric based on the total number of virtual conflicts averaged over the number of selected measurement-only resources and / or averaged over the number of resources included within the sensing window (e.g., sensing window 342) and / or resource selection window (e.g., resource selection window 344). Furthermore, in some aspects, MAC layer 302 may log virtual conflicts detected during each measurement-only resource reassessment, and UE 215 may also filter the logged virtual conflicts to determine a virtual conflict metric, as described in more detail below. MAC layer 302 can determine various metrics based on recorded or log-recorded virtual collisions. For example, MAC layer 302 can calculate the mean or average, median, variance, or any suitable statistical measure for virtual collisions.

[0126] At action 728, UE 215 can perform (e.g., transmit) a sidelink transmission based on a virtual collision metric. Regardless of whether the measurement-only resource is available, UE 215 can prevent the use of measurement-only resources to perform a sidelink transmission. Therefore, UE 215 can select one or more resources (e.g., transmission resources) for the sidelink transmission. In some aspects, resource selection and / or the transmission of the sidelink transmission can be based on a virtual collision metric. Specifically, UE 215 can determine channel access parameters (e.g., transmission parameters) for the sidelink transmission based on the virtual collision metric, and UE 215 can transmit the sidelink transmission based on the channel access parameters. For example, the channel access parameters can correspond to transmit power (e.g., transmit power level), the maximum number of retransmissions associated with the transmission, the contention window size (duration 642), and / or congestion control parameters. Therefore, the channel access parameters can affect the likelihood that UE 215 will successfully perform a sidelink transmission. For example, increasing the transmit power used for sidelink transmissions can reduce the risk of interference disrupting sidelink transmissions; increasing the maximum number of retransmissions associated with sidelink transmissions can increase the number of opportunities available for UE 215 to transmit sidelink transmissions; and as described above with reference to Figure 6, increasing the contention window size can improve the likelihood of successfully executing sidelink transmissions. Furthermore, congestion control parameters can correspond to CR limits, which regulate channel access. Increasing the CR limit can promote increased access to the channel. For example, an increased percentage of resources within the channel can be utilized.

[0127] As mentioned above, the mapping between CBR and CR can be used to regulate congestion in the channel. However, CBR estimation may be inaccurate due to various factors such as subchannel signal leakage and / or other RATs sharing the same channel. On the other hand, virtual collision metrics can provide an accurate view of the congestion experienced by UE 215, and therefore UE 215 can optimize channel access or congestion control or perform service profile shaping by mapping virtual collision metrics to CR limits. Improved congestion control can reduce channel uncertainty or transmission failures, and thus improve transmission latency and / or communication efficiency. In addition, virtual collisions are obtained as part of sidelink sensing, and therefore may be less complex than estimating CBR. Therefore, virtual collision-based channel access or congestion control can also reduce implementation complexity at UE 215 and can be suitable for lower-tier UEs with limited processing capabilities.

[0128] Therefore, as an illustrative example, for a relatively high virtual collision metric that indicates a relatively high level of channel congestion, UE 215 can use a relatively high transmit power to transmit sidelink transmissions, while for a relatively low virtual collision metric that indicates a relatively low level of channel congestion, UE 215 can use a relatively low transmit power level to transmit sidelink transmissions. Similarly, UE 215 can increase the maximum retransmission count, contention window size, and / or CR limit based on an increase in channel congestion indicated by the virtual collision metric, and can decrease the maximum retransmission count, contention window size, and / or CR limit based on a decrease in channel congestion indicated by the virtual collision metric.

[0129] Alternatively, in some aspects, UE 215 may determine channel access parameters based on the amount of resources (e.g., measuring only resources) selected for determining virtual conflict metrics (e.g., at action 720) meeting a threshold. For example, UE 215 may adjust the channel access parameters in response to the resource amount exceeding the threshold, and may use previous and / or default (e.g., predetermined) channel access parameters in response to the resource amount failing to exceed the threshold, or vice versa. In this way, UE 215 may determine channel access parameters based on the minimum number of virtual conflict measurements used to generate virtual conflict metrics (e.g., associated with the resource amount).

[0130] Furthermore, in some aspects, UE 215 can determine channel access parameters based on virtual conflict metrics meeting thresholds. For example, UE 215 can adjust channel access parameters in response to virtual conflict metrics exceeding a threshold, and can use previous and / or default (e.g., predetermined) channel access parameters in response to virtual conflict metrics failing to exceed a threshold, or vice versa. Alternatively, UE 215 can increase the value of channel access parameters in response to virtual conflict metrics exceeding a threshold, and can decrease the value of channel access parameters in response to virtual conflict metrics failing to exceed a threshold, or vice versa. In this way, UE 215 can determine channel access parameters that are sensitive to changes in virtual conflict metrics.

[0131] Figure 8 This is a sequence diagram illustrating, according to some aspects of this disclosure, a virtual collision-based channel access method 800 associated with a virtual collision metric determined based on both transmission resources and measurement resources only. Method 800 can be used by UE 215, for example, by utilizing the following... Figure 12 The components discussed in UE 1200 are used for implementation. As shown, method 800 includes a plurality of enumerated actions, but aspects of method 800 may include additional actions before, after, and between the enumerated actions. In some aspects, one or more of the enumerated actions may be omitted or performed in a different order.

[0132] Generally speaking, method 800 includes features similar to method 300 in many respects. For example, actions 810, 812, 814, and 816 are similar to actions 310, 312, 314, and 316, respectively. Therefore, for the sake of brevity, the details of these steps will not be repeated here.

[0133] At action 810, PHY layer 304 performs sensing in the side traversal resource pool. PHY layer 304 can continuously sense or monitor resources in the side traversal resource pool. Furthermore, although not shown, PHY 304 can perform sensing in the side traversal resource pool in response to a sensing request received from MAC layer 302. For example, as referenced above... Figure 7 As described in action 710, MAC layer 302 can be configured (e.g., configured by L3) to periodically, semi-periodically, and / or in response to event triggering to send sensing requests.

[0134] At action 812, MAC layer 302 sends a resource selection trigger to PHY layer 304. In some aspects, MAC layer 302 may send the resource selection trigger based on the generation and readiness of MAC Packet Data Units (PDUs) for transmission.

[0135] At action 814, PHY layer 304 identifies candidate resources. PHY layer 304 can identify candidate resources based on sensing (e.g., at action 810), and can also generate a candidate resource report based on the identified candidate resources. Therefore, at action 816, PHY layer 304 can send the candidate resource report to MAC layer 302. This report can indicate the time and frequency location information of the candidate resources.

[0136] At action 818, MAC layer 302 selects transmission resources and measurement-only resources from the candidate resources within the received candidate resource report. For example, MAC layer 302 can randomly select transmission resources and measurement-only resources from the candidate resources, where the transmission resources can be used by UE 215 for transmission (if available). As an example, if the candidate resource report includes a list of N candidate resources, MAC layer 302 can draw a random number between 1 and N (e.g., k) and select the k-th candidate resource as the transmission resource. Furthermore, in some cases, MAC layer 302 can randomly select measurement-only resources from the candidate resources by drawing another random number between 1 and N. Moreover, it is understood that MAC layer 302 can select any number of transmission resources and / or measurement-only resources from the candidate resources.

[0137] At action 820, MAC layer 302 sends a request to PHY layer 304 to re-evaluate the measurement resource only, as referenced above. Figure 7Action 722 is described similarly. At action 822, based on the resource reassessment request (measuring only resources), PHY layer 304 sends an updated resource report to MAC layer 302. In the updated resource report, PHY layer 304 can identify resources that were still available at the time the resource reassessment request was received, as described above. Figure 3A Action 322 and Figure 7 Action 724 is described similarly.

[0138] At action 824, MAC layer 302 sends a transport resource reassessment request to PHY layer 304, as referenced above. Figure 3A Action 320 is described similarly. At action 826, based on the transport resource reassessment request, the PHY layer 304 sends an updated resource report to the MAC layer 302. In the updated resource report, the PHY layer 304 can identify resources that were still available at the time the resource reassessment request was received, as described above. Figure 3A Action 322 and Figure 7 Action 724 is described similarly.

[0139] In some aspects, the transmission of the measurement-only resource re-evaluation request 820 and the transport resource re-evaluation request 824 to the PHY layer 304 can be performed by the MAC layer 302 as separate actions (e.g., actions 820 and 824, respectively), as shown. Alternatively or alternatively, the MAC layer 302 can send a single resource re-evaluation request to the PHY layer 304, which may prompt the PHY layer 304 to determine the availability of both the measurement-only resource and the transport resource. In any case, the MAC layer 302 can determine the virtual collision metric based on the availability of the measurement-only resource and the transport resource at action 828. Specifically, the MAC layer 302 can determine the virtual collision metric based on the state of the reselection flags associated with the measurement-only resource and the state of the reselection flags associated with the transport resource, which may be included in the same updated resource report or separate updated resource reports (e.g., resource report 822 and resource report 826, respectively). As described herein, the reselection flag can be set by PHY layer 304 in response to the detection of a reservation for a resource (e.g., obtained from SCI decoding) (e.g., unavailability of a resource identified during last-minute reassessment). The reselection flag can be used by MAC layer 302 as an indication of a virtual conflict at the corresponding resource.

[0140] At action 830, UE 215 can perform (e.g., transmit) sidelink transmissions based on virtual collision metrics. For example, as referenced above. Figure 7As described in action 728, UE 215 can transmit sidelink transmissions based on channel access parameters, and UE 215 can determine the channel access parameters based on virtual collision metrics. Furthermore, if transmission resources are indicated as available in an updated resource report (e.g., at action 826), UE 215 can use the transmission resources to perform sidelink transmissions. Otherwise, UE 215 can reselect resources for transmitting sidelink transmissions.

[0141] In some respects, UE 215 can employ method 800 in conjunction with method 700. For example, UE 215 can use method 700 to perform measurement-only sensing to determine virtual conflict metrics over a period of time, and can subsequently use method 800 to determine or update the virtual conflict metrics based on measurement-only resources and transmission resources. Generally, UE 215 can determine virtual conflict metrics based on measurement-only resources, transmission resources, or a combination thereof.

[0142] Figure 9 This is a sequence diagram illustrating a method 900 for channel access optimization configuration based on virtual collisions, according to some aspects of this disclosure. Method 900 can be used by UE 215, for example, by utilizing the following... Figure 12 The components discussed in UE 1200 are used for implementation. Specifically, method 900 can be used to configure the MAC layer 302 of UE 215 to determine and utilize virtual conflict metrics, as described herein. As shown, method 900 includes a plurality of enumerated actions, but aspects of method 900 may include additional actions before, after, and between the enumerated actions. In some aspects, one or more of the enumerated actions may be omitted or performed in a different order.

[0143] At action 910, L3 904 of UE 215 can send a virtual collision-based channel access optimization setting to MAC layer 302 of UE 215. L3 904 can refer to the network layer of UE 215. Furthermore, the virtual collision-based channel access optimization setting can configure MAC layer 302 to determine and / or use virtual collision metrics.

[0144] For example, in some aspects, a channel access optimization setting based on virtual collisions can configure MAC layer 302 to determine a virtual collision metric based solely on virtual collisions at the measured resource. In this case, the channel access optimization setting based on virtual collisions can configure MAC layer 302 to perform one or more actions of method 700. In some aspects, a channel access optimization setting based on virtual collisions can configure MAC layer 302 to determine a virtual collision metric based on virtual collisions at the transmission resource. In this case, the channel access optimization setting based on virtual collisions can configure MAC layer 302 to determine a virtual collision metric based on virtual collisions identified in association with the transmission, such as based on... Figure 3A Action 322 identifies virtual collisions based on the updated resource report received at MAC 302. Furthermore, in some aspects, the virtual collision-based channel access optimization setting can configure MAC layer 302 to determine a virtual collision metric based on a combination of virtual collisions corresponding to transmission resources or only measured resources. In this case, for example, the virtual collision-based channel access optimization setting can configure MAC layer 302 to perform one or more actions of method 800.

[0145] In any case, the virtual collision-based channel access optimization settings can configure MAC layer 302 to determine virtual collision metrics periodically, semi-periodically, based on event triggering, or a combination thereof. In some aspects, event triggering may include UE 215 entering a specific geographic area, such as entering or leaving coverage area 210. Alternatively or additionally, MAC layer 302 may be triggered to determine virtual collision metrics if the packet delay budget (PDB) at UE 215 fails to meet a predefined (e.g., threshold) number of times. UE 215 may fail to meet the PDB when it cannot obtain resources for transmissions within the PDB, for example, due to a higher number of reselections or failure to identify candidates within the PDB. Furthermore, in some aspects, event triggering may be based on the number of retransmissions (e.g., the average number of retransmissions over a time window) exceeding a threshold and / or the average number of virtual collisions within the time window exceeding a threshold.

[0146] Furthermore, in some aspects, L3 904 can configure conditions for UE 215 to perform virtual conflict-based channel access via virtual conflict-based channel access optimization settings. For example, the virtual conflict-based channel access optimization settings can specify that UE 215 may not perform virtual conflict-based channel access (e.g., disallow virtual conflict-based channel access). In such cases, for example, UE 215 can estimate channel congestion based on CBR measurement results. In some cases, the virtual conflict-based channel access optimization settings can indicate that virtual conflict-based channel access is allowed. In such cases, UE 215 can decide whether to access the channel based on CBR measurement results or perform virtual conflict-based channel access. In some cases, the virtual conflict-based channel access optimization settings can include flags indicating whether virtual conflict-based channel access is allowed or disallowed. In some cases, virtual conflict-based channel access can be allowed based on the capabilities of UE 215. For example, virtual conflict-based channel access can be allowed for low-capability UEs (e.g., UEs with relatively low-complexity receiver implementations) and, for example, may not be allowed for high-capability UEs or other RATs. In some cases, the virtual conflict-based channel access optimization settings may include a capability level parameter indicating which UE capability level (e.g., high capability, medium capability, low capability) is allowed to utilize virtual conflict-based channel access. Furthermore, in some aspects, virtual conflict-based channel access may be allowed based on the UE 215 being located in a specific area (e.g., geographic location) (e.g., within certain coverage areas) and / or the UE 215 accessing the channel within a certain time range (e.g., at a specific time of day). In some aspects, virtual conflict-based channel access may be allowed when the UE 215 detects other RATs using the channel. Additionally, virtual conflict-based access may be allowed based on any combination of factors described herein (e.g., UE location, UE capability, time of channel access, or detection of other RATs). In some cases, the virtual conflict-based channel access optimization settings may include a bitmap, where each bit in the bitmap may correspond to a rule or condition for utilizing virtual conflict-based channel access, and L3 904 may set or clear a bit to indicate whether virtual conflict-based channel access should satisfy that rule or condition.

[0147] Alternatively or concurrently, the virtual collision-based channel access optimization settings may include one or more of the thresholds described herein. For example, the virtual collision-based channel access optimization settings may include a maximum number of measurement-only resources to be selected by MAC layer 302, a number of thresholds for virtual collision measurements to be used to determine virtual collision metrics, thresholds for determining whether virtual collision metrics for channel access parameters must be met or not met, and so on. Typically, the virtual collision-based channel access optimization settings may be statically configured, semi-statically configured, or dynamically updated to allow flexibility, for example, to adapt to network traffic load and / or channel conditions.

[0148] At action 912, MAC layer 302 and PHY layer 304 can perform virtual conflict-based channel access. Specifically, UE 215 can perform transmissions (e.g., sidelink transmissions) based on a virtual conflict metric determined by one or more actions performed at MAC layer 302 and PHY layer 304. For example, according to virtual conflict-based channel access optimization settings, MAC layer 302 and PHY layer 304 can perform one or more actions of method 700 or method 800 to perform virtual conflict-based channel access. Alternatively or alternatively, MAC layer 302 and PHY layer 304 can perform virtual conflict-based channel access without determining the virtual conflict metric based solely on resource measurements. In some aspects, for example, MAC layer 302 can select one or more transmission resources, request a resource re-evaluation of the selected one or more transmission resources, and determine the virtual conflict metric based on the availability of the transmission resources.

[0149] Furthermore, in some aspects, the virtual collision-based channel optimization settings allow UE 215 (e.g., via MAC layer 302 and PHY layer 304) to selectively perform virtual collision-based channel access based on a virtual collision metric determined using only measured resources, based on transmission resources, or based on a combination thereof. That is, for example, UE 215 can selectively perform the actions of methods 700 and 800, or UE 215 can determine the virtual collision metric based on transmission resources according to the virtual collision-based channel optimization settings. Specifically, UE 215 can be configured to determine the virtual collision metric and / or perform virtual collision-based channel access based on optimizations to transmit power, maximum retransmission count, and / or service profile, according to the virtual collision-based channel access optimization settings. For example, determining the virtual collision metric based solely on transmission resources can be relatively inexpensive in terms of power and / or resource consumption at UE 215. However, the reliability of virtual collision metrics as indicators of channel congestion can depend in part on the transmission frequency at UE 215, since the impact of random virtual collisions in a relatively uncongested channel can decrease with increasing sample size (e.g., where the virtual collision metric is determined based on increased transmission resources). On the other hand, determining the virtual collision metric based on both transmission resources and measurement-only resources may be relatively more expensive and relatively more reliable as an indicator of channel congestion in terms of power and / or resource consumption at UE 215. Furthermore, determining the virtual collision metric based solely on measurement-only resources can involve using power and resources at UE 215 specifically for determining the virtual collision metric, rather than partially for transmission. Moreover, because the use of measurement-only resources can be independent of transmission at UE 215, the number of samples included in the virtual collision metric can be easily increased, thereby increasing the reliability of the virtual collision metric.

[0150] Furthermore, in some cases, virtual conflict-based channel optimization settings can enable UE 215 to perform virtual conflict-based channel access based on the resource pool that UE 215 attempts to access and / or use for transmission. For example, to access a resource pool associated with a channel, UE 215 may need to verify that the virtual conflict metric detected at UE 215 meets a threshold. For example, if the virtual conflict metric fails to meet the threshold, UE 215's access to the resource pool can be denied. For example, if the average number of virtual conflicts detected by UE 215 (e.g., over a certain time period and / or associated with a certain number of samples) exceeds a predetermined threshold, UE 215 may be unable to access the resource pool until UE 215 adjusts one or more parameters (e.g., channel access parameters) and / or, for example, detects a virtual conflict metric that meets the threshold. Controlling access or admission to a specific side link resource pool based on virtual conflict metrics can be useful. For example, UE 215 can be configured with multiple sidelink resource pools with different Quality of Service (QoS) requirements, and a particular sidelink resource pool can have more stringent QoS requirements than other sidelink resource pools, for example, to serve Ultra Reliable Low Latency Communication (URLLC) services. Therefore, controlling access to a specific sidelink resource pool based on a certain virtual conflict metric can allow URLLC services to meet the latency and / or reliability requirements of URLLC.

[0151] Figure 10 This is a sequence diagram illustrating a method 1000 for configuring a virtual conflict measurement report according to some aspects of this disclosure. Method 1000 can be performed by one or more UEs 215 (such as a first UE 215a and a second UE 215c). Figure 2 As shown in the diagram, and implemented with BS 205. Specifically, method 1000 can be used to configure UE 215 (e.g., UE 215a) to report virtual conflict metrics to BS 205, and to optimize one or more UE 215s (e.g., 215a and / or 215c) based on the reported metrics. Each of UE 215a and 215b can utilize as follows for... Figure 12 The components discussed in UE 1200 are used to implement method 1000, and BS 205 can utilize the following for Figure 11 The components discussed in BS 1100 are used to implement method 1000. As shown, method 1000 includes a plurality of enumerated actions, but aspects of method 1000 may include additional actions before, after, and between the enumerated actions. In some aspects, one or more of the enumerated actions may be omitted or performed in a different order.

[0152] At action 1010, BS 205 can send a virtual conflict measurement report configuration to the first UE 215a. The virtual conflict measurement report configuration enables the first UE 215a to report information associated with virtual conflict measurements detected by the first UE 215a to BS 205. Specifically, the virtual conflict measurement report configuration can enable the first UE 215a to report virtual conflict measurements periodically, semi-periodically, or in response to events (e.g., event triggering). For example, the virtual conflict measurement report configuration can enable the first UE 215a to report virtual conflict measurements in response to events such as the first UE 215a moving its location, timer elapsed, virtual conflict measurements exceeding a threshold, changes in virtual conflict measurement reports relative to previous reports, etc.

[0153] At action 1012, the first UE 215a may send a virtual conflict measurement report to the BS 205 according to the virtual conflict measurement report configuration. That is, for example, as described above, the first UE 215a may send the virtual conflict measurement report periodically and / or in response to an event triggered by the virtual conflict measurement report configuration. Furthermore, in some aspects, the virtual conflict measurement report may include an indication of the location of the first UE 215a. For example, the report may include an area ID, coordinates, and / or Global Positioning System (GPS) information indicating the location of the UE 215a.

[0154] In some aspects, the first UE 215a can be configured to store a virtual conflict log, which includes a record of the number of virtual conflicts detected at the first UE 215a. For example, the first UE 215a can store the virtual conflict log in its memory (e.g., memory 1204). Therefore, the first UE 215a can update the virtual conflict log over time.

[0155] In some respects, the first UE 215a may send a virtual conflict log or a portion thereof to the BS 205 as a virtual conflict metric report. For example, the UE 215a may send any entries in the virtual conflict log that were not previously sent to the BS 205 in a virtual conflict metric report (e.g., the set of most recent entries in the virtual conflict log). Alternatively or additionally, the first UE 215a may apply filters to the virtual conflict log. For example, the first UE 215a may determine the virtual conflict metric based on the number of virtual conflicts occurring within a time window (e.g., entries in the virtual conflict log), and the first UE 215a may send an indication of the virtual conflict metric to the BS 205 in the virtual conflict metric report.

[0156] At action 1014, BS 205 can determine sidelink channel access optimization based on the virtual collision metric report. In some cases, sidelink channel access optimization can correspond to the above reference. Figure 9 The description describes virtual collision-based channel access optimization. For example, sidelink channel access optimization may involve adjusting the period of virtual collision-based channel access. More specifically, sidelink channel access optimization may involve adjusting the period of virtual collision measurement and / or adjusting channel access parameters. For example, sidelink channel access optimization may specify a threshold for determining whether to adjust channel access parameters based on virtual collision metrics. Alternatively or additionally, sidelink channel access optimization may involve adjusting the maximum number of measurement-only resources selected by MAC layer 302 for measuring virtual collisions (e.g., via a last-minute re-evaluation of the measurement-only resources). To this end, in some aspects, sidelink channel access optimization may involve enabling (e.g., allowing) the use of measurement-only resources when determining virtual collision metrics. For example, sidelink channel access optimization may enable UE215 to perform one or more actions of method 700 or 800.

[0157] As an illustrative example, based on virtual collision metric reports indicating a relatively high level of channel congestion (e.g., frequent virtual collisions and / or the number of virtual collisions on the channel exceeding a threshold), sidelink channel access optimization may involve increasing the period of virtual collision measurements, increasing the period of channel access parameter adjustments (e.g., in response to virtual collision metrics), increasing the maximum number of resources to be measured only, implementing the use of resources to be measured only for virtual collision metrics, or a combination thereof. Similarly, based on virtual collision metric reports indicating a relatively low level of channel congestion (e.g., infrequent virtual collisions and / or the number of virtual collisions on the channel below a threshold), sidelink channel access optimization may involve reducing the period of virtual collision measurements, reducing the period of channel access parameter adjustments (e.g., in response to virtual collision metrics), reducing the maximum number of resources to be measured only, prohibiting the use of resources to be measured only for virtual collision metrics, or a combination thereof.

[0158] Furthermore, in some aspects, sidelink channel access optimization may involve triggering virtual collision logging at a second UE (e.g., UE 215c). Alternatively or concurrently, sidelink channel access optimization may involve triggering virtual collision-based channel access optimization at the second UE 215c. The sidelink channel access optimization may be the same for the first UE 215a and the second UE 215c, or it may be different between the two UEs (e.g., UE 215a and UE 215c).

[0159] At action 1016, BS 205 can send an optimized configuration based on sidelink virtual conflict metrics to the second UE 215c based on sidelink channel access optimization. Similarly, at action 1018, BS 205 can send an optimized configuration based on sidelink virtual conflict metrics to the first UE 215a based on sidelink channel access optimization. The optimized configuration based on sidelink virtual conflict metrics sent to the second UE 215c based on sidelink channel access optimization can be the same as or different from the optimized configuration based on sidelink virtual conflict metrics sent to the first UE 215a.

[0160] In some respects, UE 215 can utilize the above-mentioned... Figure 4 , 5 The virtual conflict metrics discussed in 6A-6B, 7, 8, 9 and 10 are determined and / or configured in any suitable combination.

[0161] Figure 11 This is a block diagram of an exemplary BS 1100 based on some aspects of this disclosure. BS 1100 can be as described above... Figure 1 The network 100 discussed herein includes a BS 105. As shown, the BS 1100 may include a processor 1102, a memory 1104, a virtual collision module 1108, a transceiver 1110 including a modem subsystem 1112 and an RF unit 1114, and one or more antennas 1116. These components may communicate directly or indirectly with each other, for example, via one or more buses.

[0162] Processor 1102 may have various features as a particular type of processor. For example, these features may include a CPU, DSP, ASIC, controller, FPGA device, another hardware device, firmware device, or any combination thereof configured to perform the operations described herein. Processor 1102 may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0163] Memory 1104 may include cache memory (e.g., cache memory of processor 1102), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, solid-state memory devices, one or more hard disk drives, memristor-based arrays, other forms of volatile and non-volatile memory, or combinations of different types of memory. In some aspects, memory 1104 may include non-transitory computer-readable media. Memory 1104 may store instructions 1106. Instructions 1106 may include causing processor 1102 to perform the operations described herein when executed by processor 1102 (e.g., ...). Figure 1-2Instructions (and aspects of 10). Instructions 1106 may also be referred to as program code. Program code can be used to cause wireless communication devices to perform these operations, for example by causing one or more processors (such as processor 1102) to control or command the wireless communication devices to do so. The terms “instruction” and “code” should be interpreted broadly to include any type of computer-readable statement. For example, the terms “instruction” and “code” can refer to one or more programs, routines, subroutines, functions, procedures, etc. “Instruction” and “code” can include a single computer-readable statement or many computer-readable statements.

[0164] The virtual collision module 1108 can be implemented via hardware, software, or a combination thereof. For example, the virtual collision module 1108 can be implemented as a processor, circuitry, and / or instructions 1106 stored in memory 1104 and executed by processor 1102. In some examples, the virtual collision module 1108 can be integrated within the modem subsystem 1112. For example, the virtual collision module 1108 can be implemented by a combination of software components (e.g., executed by a DSP or general-purpose processor) and hardware components (e.g., logic gates and circuitry) within the modem subsystem 1112.

[0165] The virtual conflict module 1108 can communicate with one or more components of the BS 1100 to perform various aspects of this disclosure, such as... Figure 1-2 The virtual collision module 1108 is configured to configure a sidelink configuration (e.g., sidelink resource pool 350) for sidelink communication for the UE (e.g., UE 115, 215). The virtual collision module 1108 can also be configured to configure a virtual collision metric reporting configuration for the UE (e.g., action 1010), determine sidelink channel access optimization (e.g., action 1012), and / or configure an optimization configuration for the UE based on sidelink virtual collision metrics (e.g., actions 1016 and / or action 1018).

[0166] As shown in the figure, transceiver 1110 may include modem subsystem 1112 and RF unit 1114. Transceiver 1110 may be configured to communicate bidirectionally with other devices, such as UE 115 and / or another core network element. Modem subsystem 1112 may be configured to modulate and / or encode data according to MCS (e.g., LDPC coding scheme, turbo coding scheme, convolutional coding scheme, digital beamforming scheme, etc.). RF unit 1114 may be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) modulated / coded data transmitted from modem subsystem 1112 (on outbound transmissions) or originating from another source (such as UE 115) (e.g., RRC configuration, sidelink resource pool configuration, optimized configuration based on sidelink virtual collision metric). RF unit 1114 may also be configured to perform analog beamforming in conjunction with digital beamforming. Although shown as integrated together in transceiver 1110, modem subsystem 1112 and / or RF unit 1114 may be separate devices coupled together at BS 105 so that BS 105 can communicate with other devices.

[0167] RF unit 1114 can provide modulated and / or processed data (e.g., data packets (or, more generally, data messages containing one or more data packets and other information)) to antenna 1116 for transmission to one or more other devices. Antenna 1116 can also receive data messages transmitted from other devices and provide the received data messages for processing and / or demodulation at transceiver 1110. Transceiver 1110 can provide demodulated and decoded data (e.g., virtual collision metric reports) to virtual collision module 1108 for processing. Antenna 1116 may include multiple antennas of similar or different designs to maintain multiple transmission links.

[0168] In one aspect, BS 1100 may include multiple transceivers 1110 implementing different RATs (e.g., NR and LTE). In another aspect, BS 1100 may include a single transceiver 1110 implementing multiple RATs (e.g., NR and LTE). In yet another aspect, transceiver 1110 may include various components, wherein different combinations of components can implement different RATs.

[0169] Figure 12 This is a block diagram of an exemplary UE 1200 based on some aspects of this disclosure. UE 1200 can be as described above for... Figure 1 The UE 115 discussed above, or as mentioned above, is for... Figure 2 , 3AUE 215 is discussed in -3B, 4-10, 13, and 14. As shown in the figure, UE 1200 may include a processor 1202, a memory 1204, a virtual conflict module 1208, a transceiver 1210 including a modem subsystem 1212 and a radio frequency (RF) unit 1214, and one or more antennas 1216. These components may communicate directly or indirectly with each other, for example, via one or more buses.

[0170] Processor 1202 may include a central processing unit (CPU), digital signal processor (DSP), application-specific integrated circuit (ASIC), controller, field-programmable gate array (FPGA) device, another hardware device, firmware device, or any combination thereof configured to perform the operations described herein. Processor 1202 may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0171] Memory 1204 may include cache memory (e.g., cache memory of processor 1202), random access memory (RAM), magnetoresistive RAM (MRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, solid-state memory devices, hard disk drives, other forms of volatile and non-volatile memory, or combinations of different types of memory. In one aspect, memory 1204 includes a non-transitory computer-readable medium. Memory 1204 may store or record instructions 1206 thereon. Instructions 1206 may include, when executed by processor 1202, causing processor 1202 to perform aspects of this document combined with the present disclosure (e.g., ...). Figure 2 , 3A (Aspects of -3B, 4-10, 13, and 14) Instructions for the various operations described in UE 115 and / or 215. Instruction 1206 may also be referred to as program code, which can be broadly interpreted as including instructions as described above for the operations described in UE 115 and / or 215. Figure 12 Any type of computer-readable statement discussed.

[0172] The virtual collision module 1208 can be implemented via hardware, software, or a combination thereof. For example, the virtual collision module 1208 can be implemented as a processor, circuitry, and / or instructions 1206 stored in memory 1204 and executed by processor 1202. In some examples, the virtual collision module 1208 can be integrated within the modem subsystem 1212. For example, the virtual collision module 1208 can be implemented by a combination of software components (e.g., executed by a DSP or general-purpose processor) and hardware components (e.g., logic gates and circuitry) within the modem subsystem 1212.

[0173] The virtual conflict module 1208 can communicate with one or more components of the UE 1200 to perform various aspects of this disclosure, such as... Figures 3A-3B In aspects of 4-10, 13, and 14. In some aspects, the virtual conflict module 1208 is configured to determine virtual conflict metrics based on the availability of one or more resources, such as for... Figure 4-10 The points discussed in sections 13 and 14.

[0174] The virtual collision module 1208 is also configured to perform sensing in the side link resource pool. Sensing or monitoring may include decoding the SCI and / or measuring the signal energy in the channel. The virtual collision module 1208 may be configured to blindly decode the SCI from the PSCCH of each resource, record the decoded SCI upon successful decoding, determine the signal measurement results (e.g., RSRP and / or RSSI) for each resource, and record the signal measurement results.

[0175] The virtual collision module 1208 is also configured to select one or more resources based on sensing, such as measuring resources and / or transmission resources only. The virtual collision module 1208 can determine a virtual collision metric based on the availability of one or more selected resources. For example, the virtual collision module 1208 can request and / or perform a last-minute reassessment of each of the selected resources, and the virtual collision module 1208 can determine resource availability based on the state of a reselection flag associated with the resource. The virtual collision module 1208 can also be configured to adjust and / or determine channel access parameters based on the virtual collision metric.

[0176] As shown, transceiver 1210 may include modem subsystem 1212 and RF unit 1214. Transceiver 1210 may be configured to communicate bidirectionally with other devices, such as BS 105. Modem subsystem 1212 may be configured to modulate and / or encode data from memory 1204 and / or virtual collision module 1208 according to modulation and coding schemes (MCS) (e.g., low-density parity-check (LDPC) coding scheme, turbo coding scheme, convolutional coding scheme, digital beamforming scheme, etc.). RF unit 1214 may be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) modulated / coded data (e.g., PSCCH SCI, PSSCH data, virtual collision metric report) transmitted from modem subsystem 1212 (on outbound transmissions) or originating from another source (e.g., UE 115 or BS 105). RF unit 1214 may also be configured to perform analog beamforming in conjunction with digital beamforming. Although shown as being integrated together in transceiver 1210, modem subsystem 1212 and RF unit 1214 can be separate devices coupled together at UE 115 to enable UE 115 to communicate with other devices.

[0177] RF unit 1214 can provide modulated and / or processed data (e.g., data packets (or more generally, data messages that may include one or more data packets and other information)) to antenna 1216 for transmission to one or more other devices. Antenna 1216 can also receive data messages transmitted from other devices. Antenna 1216 can provide the received data messages for processing and / or demodulation at transceiver 1210. Transceiver 1210 can provide demodulated and decoded data (e.g., RRC configuration, sidelink resource pool configuration, PSCCH SCI, PSSCH data, optimized configuration based on sidelink virtual collision metric) to virtual collision module 1208 for processing. Antenna 1216 may include multiple antennas of similar or different designs to maintain multiple transmission links. RF unit 1214 can configure antenna 1216.

[0178] In some aspects, processor 1202 is configured to communicate with one or more components of UE 1200 to select multiple resources from a sidelink resource pool, request an assessment of the availability of the multiple resources, and receive indications of the availability of the multiple resources. In some aspects, processor 1202 is configured to communicate with one or more components of UE 1200 to perform measurement-only sensing in the sidelink resource pool. Specifically, processor 1202 may be configured to select multiple measurement-only resources from the sidelink resource pool and obtain the availability of the multiple measurement-only resources.

[0179] Transceiver 1210 can be configured to communicate with one or more components of UE 1200 to transmit first-side link transmissions based on virtual conflict metrics associated with indications of availability of multiple resources. Transceiver 1210 can be configured to transmit first-side link transmissions based on virtual conflict metrics associated with availability of multiple measurement-only resources obtained from measurement-only sensing.

[0180] In one aspect, UE 1200 may include multiple transceivers 1210 implementing different RATs (e.g., NR and LTE). In another aspect, UE 1200 may include a single transceiver 1210 implementing multiple RATs (e.g., NR and LTE). In yet another aspect, transceiver 1210 may include various components, wherein different combinations of components can implement different RATs.

[0181] Figure 13 This is a flowchart of a wireless communication method 1300 according to some aspects of this disclosure. Aspects of method 1300 can be performed by a computing device of a wireless communication device (e.g., a processor, processing circuitry, and / or other suitable components) or other suitable units for performing these steps. For example, a wireless communication device (such as UE 115, 215, 1200) can utilize one or more components (such as processor 1202, memory 1204, virtual collision module 1208, transceiver 1210, modem 1212, and one or more antennas 1216) to perform the steps of method 1300. Method 1300 can be implemented as described above. Figures 3A-3B Similar mechanisms are described in 4, 5, 6, 7, 8, A-9, and 10. As shown in the figure, method 1300 includes a plurality of enumerated steps, but aspects of method 1300 may include additional steps before, after, and between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order.

[0182] At box 1310, the UE can select multiple resources from the sidelink resource pool. For example, the UE can perform sensing in the sidelink resource pool via the PHY layer (e.g., PHY layer 304), as described above with reference to action 310 in Figure 3. Figure 7 Actions 712 and 810 are described above. Based on this sensing, the UE can select (e.g., via the MAC layer) one or more available candidate resources, as described in action 318 of Figure 3 above. Figure 7 Action 720 and Figure 8As described in action 818. In some aspects, the selected resource may be a transmission resource, a measurement-only resource, or a combination thereof. Furthermore, the sidelink resource pool may be in a licensed frequency band and / or in an unlicensed frequency band. Additionally, the UE may select multiple resources based on a resource selection trigger. In some aspects, the UE may utilize one or more components (such as processor 1202, memory 1204, virtual collision module 1208, transceiver 1210, modem 1212, and one or more antennas 1216) to perform the operation at block 1310.

[0183] At box 1320, the UE may request an assessment of the availability of multiple resources. For example, the UE may request a resource reassessment (e.g., last-minute reassessment) of multiple resources via the MAC layer (e.g., MAC layer 302), as referenced. Figure 3A Action 320 Figure 7 Action 722 and Figure 8 Actions 820 and 824 are described. In some aspects, the UE may use a single resource reassessment request to request an assessment of the availability of each of a plurality of resources. For example, the UE may request assessments of both a first resource and a second resource simultaneously. In some aspects, the UE may send a first assessment request for the first resource at a first time and a second assessment request for the second resource at a second time. In some aspects, for example, the first resource may be a measurement-only resource and the second resource may be a transmission resource. In some aspects, the UE may utilize one or more components (such as processor 1202, memory 1204, virtual collision module 1208, transceiver 1210, modem 1212, and one or more antennas 1216) to perform the operation at block 1320.

[0184] At box 1330, the UE can receive indications of the availability of multiple resources. For example, the UE can receive updated resource reports from the PHY layer (e.g., PHY layer 304), as referenced. Figure 3A Action 322 Figure 7 Action 724 and Figure 8 As described in actions 822 and 826. The updated resource report can indicate whether a resource is available or unavailable based on a last-minute reassessment of the resource. Specifically, if the resource is unavailable, the UE can receive a reselection flag associated with the resource. Otherwise, the UE can receive an indication that the resource is available. As an illustrative example, a reselection flag associated with available resources may not be set. In some aspects, the UE can utilize one or more components, such as processor 1202, memory 1204, virtual conflict module 1208, transceiver 1210, modem 1212, and one or more antennas 1216, to perform the operation at block 1330.

[0185] At block 1340, the UE may transmit a first sidelink transmission based on a virtual conflict metric associated with an indication of the availability of multiple resources. The UE may use resources in the sidelink resource pool to transmit the first sidelink transmission. As described herein, an indication of resource unavailability (e.g., a resource reselection flag) may correspond to a virtual conflict at that resource between the UE and another wireless communication device that previously reserved that resource. Therefore, in some aspects, the UE may determine the virtual conflict metric based on an indication of one or more unavailable resources in the indication of the availability of multiple resources. Specifically, the UE may determine the virtual conflict metric based on the number of resources indicated as unavailable in the indication of the availability of multiple resources (e.g., the number of virtual conflicts). The UE may also determine the virtual conflict metric based on a virtual conflict log that stores records of unavailable resources. For example, the UE may store the virtual conflict log in memory (e.g., memory 1204) and may update the virtual conflict log over time. In some aspects, the UE may apply filters to the virtual conflict log and may further determine the virtual conflict metric based on the filtered virtual conflict log. In some respects, for example, the UE may filter virtual conflict logs based on a moving (e.g., rolling) time window, average virtual conflicts on a last-minute reassessment of resources, and so on. In some respects, the UE may utilize one or more components (such as processor 1202, memory 1204, virtual conflict module 1208, transceiver 1210, modem 1212, and one or more antennas 1216) to perform the operations at block 1340.

[0186] In some aspects, the UE can perform first-side hop transmissions based on virtual collision metrics meeting thresholds. For example, the UE can determine that the frequency of virtual collisions within a time window is below a certain threshold, the ratio of virtual collisions to resources remaining available during last-minute reassessment is below a predetermined threshold, and so on. Alternatively or additionally, the UE can determine channel access parameters for first-side hop transmissions based on virtual collision metrics, and the UE can transmit first-side hop transmissions according to the channel access parameters. Channel access parameters can be associated with transmit power, maximum retransmission count, contention window size, congestion control parameters (e.g., CR limit), etc., for first-side hop transmissions. In some aspects, the UE can further determine channel access parameters based on virtual collision logging periods meeting thresholds. Specifically, the UE can determine channel access parameters based on the number of entries (e.g., virtual collision metrics and / or virtual collision measurement results) and / or the time periods spanned by the virtual collision log entries meeting thresholds. To this end, the UE can log virtual collision metrics to meet access channel and / or resource pool requirements.

[0187] Furthermore, in some aspects, performing the first sidelink transmission at block 1340 may involve the UE selecting a second resource from the sidelink resource pool for the first sidelink transmission based on congestion control, and determining congestion control using virtual conflict metrics based on configuration. That is, for example, the UE may use virtual conflict metrics for congestion control in addition to or as an alternative to CBR-based congestion control. As described herein, the UE may use virtual conflict metrics for congestion control based on L3 (e.g., L3 904) configuration of the MAC layer and / or based on configuration received from the BS (e.g., BS 205). Furthermore, the UE may be configured to select a second resource in response to determining that the first resource is unavailable based on a last-minute reassessment (e.g., in response to identifying virtual conflicts at the first resource).

[0188] In some respects, the UE can also send reports indicating virtual conflict metrics to the BS. The UE can send reports based on a reporting cycle and / or a reporting trigger. The reporting cycle and / or reporting trigger can be configured by the BS at the UE. For example, the UE can receive configuration from the BS for reporting virtual conflict metrics, as referenced above. Figure 10 As described.

[0189] Figure 14 This is a flowchart of a wireless communication method 1400 according to some aspects of this disclosure. Aspects of method 1400 can be performed by a computing device of a wireless communication device (e.g., a processor, processing circuitry, and / or other suitable components) or other suitable units for performing these steps. For example, a wireless communication device (such as UE 115, 215, 1200) can utilize one or more components (such as processor 1202, memory 1204, virtual collision module 1208, transceiver 1210, modem 1212, and one or more antennas 1216) to perform the steps of method 1400. Method 1400 can be implemented as described above. Figures 3A-3B Similar mechanisms to those described in 1, 4, 5, 6, 7, 8, 9, 10, and 13. As shown in the figure, method 1400 includes multiple enumerated steps, but aspects of method 1400 may include additional steps before, after, and between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order.

[0190] At box 1410, the UE can perform measurement-only sensing in a sidelink resource pool. In some aspects, performing measurement-only sensing in a sidelink resource pool may involve: selecting multiple measurement-only resources from the sidelink resource pool (e.g., at subbox 1412), and obtaining the availability of multiple measurement-only resources (e.g., at subbox 1414). For example, the UE can select multiple measurement-only resources, as referenced above. Figure 7 As described in action 720, the UE can obtain the availability of multiple measurement-only resources by requesting an assessment of their availability. The UE can also obtain the availability of multiple measurement-only resources by receiving an indication of their availability. Specifically, the UE can request a last-minute reassessment of the multiple measurement-only resources at the MAC layer, and the UE can generate an updated resource report indicating the availability of the multiple measurement-only resources based on the last-minute assessment at the PHY layer. In some aspects, the UE can utilize one or more components (such as processor 1202, memory 1204, virtual collision module 1208, transceiver 1210, modem 1212, and one or more antennas 1216) to perform the operations at block 1410.

[0191] In some aspects, the UE can perform measurement-only sensing based on a measurement-only sensing configuration. In some aspects, the measurement-only sensing configuration may include an indication of a period. Thus, the UE can select multiple measurement-only resources based on a period (at subframe 1412). Additionally or alternatively, the measurement-only sensing configuration may include an indication of an event associated with at least one of a geographic area, a lost packet delay budget (PDB), and / or a virtual conflict metric threshold, and the UE can select multiple measurement-only resources based on detecting the indicated event. Furthermore, in some aspects, the UE can receive the measurement-only sensing configuration at the MAC layer. For example, the MAC layer can receive the measurement-only sensing configuration from L3. Furthermore, in some aspects, the UE can receive the measurement-only sensing configuration from the BS.

[0192] At block 1420, the UE may transmit a first sidelink transmission based on a virtual collision metric associated with the availability of multiple measurement-only resources. The UE may use resources from a sidelink resource pool to transmit the first sidelink transmission. As described herein, the UE may prevent transmission using measurement-only resources. Therefore, the UE may use different resources selected from the sidelink resource pool to perform the first sidelink transmission. For example, in some aspects, the UE may select resources for the first sidelink transmission based on a virtual collision metric. In some aspects, the UE may utilize one or more components, such as processor 1202, memory 1204, virtual collision module 1208, transceiver 1210, modem 1212, and one or more antennas 1216, to perform the operation at block 1420.

[0193] Other aspects of this disclosure include the following:

[0194] 1. A method for wireless communication performed by a user equipment (UE), the method comprising:

[0195] Select multiple resources from the sidelink resource pool;

[0196] Request an assessment of the availability of the aforementioned resources;

[0197] Receive an indication of the availability of the plurality of resources; and

[0198] The first side link transmission is sent based on a virtual conflict metric associated with the indication of availability of the plurality of resources.

[0199] 2. The method described according to Clause 1, wherein:

[0200] Receiving the indication of availability of the plurality of resources includes:

[0201] Receive an indication that one or more of the plurality of resources are unavailable; and

[0202] The method further includes:

[0203] The virtual conflict metric is determined based on the indication that one or more of the resources are unavailable.

[0204] 3. The method described in Clause 2 further includes:

[0205] A virtual conflict log is stored, which includes a record of the number of the one or more resources that are unavailable.

[0206] 4. The method according to Clause 3, wherein determining the virtual conflict metric further comprises:

[0207] Apply the filter to the virtual conflict log.

[0208] 5. The method according to any one of Clauses 1-4, wherein the first resource among the plurality of resources is a measurement-only resource.

[0209] 6. The method according to any one of clauses 1-4, wherein selecting the plurality of resources includes:

[0210] The first resource and the second resource are selected from the plurality of resources based on a resource selection trigger. The first resource is a measurement-only resource, and the second resource is a transmission resource to be used for side link transmission.

[0211] 7. The method according to Clause 6, wherein requesting an evaluation of the plurality of resources includes:

[0212] Send a first evaluation request for the measured-only resource at the first moment; and

[0213] A second evaluation request for the second resource is sent at a second time, which is different from the first time.

[0214] 8. The method according to any one of clauses 1-7, wherein sending the first-side crosslink transmission based on the virtual collision metric further comprises:

[0215] The channel access parameters for the first-side crosslink transmission are determined based on the virtual collision metric.

[0216] 9. The method according to Clause 8, wherein the channel access parameter is the transmit power for transmission on the first side link.

[0217] 10. The method according to Clause 8, wherein the channel access parameter is the maximum number of retransmissions.

[0218] 11. The method according to Clause 8, wherein the channel access parameter is the contention window size.

[0219] 12. The method according to Clause 8, wherein the channel access parameter is a congestion control parameter.

[0220] 13. The method according to Clause 8, wherein determining the channel access parameters includes:

[0221] The channel access parameters are determined based on whether the virtual conflict log recording period meets the threshold.

[0222] 14. The method according to Clause 8, wherein determining the channel access parameters includes:

[0223] The channel access parameters are determined based on the number of the plurality of resources selected for determining the virtual conflict metric meeting a threshold.

[0224] 15. The method according to Clause 8, wherein determining the channel access parameters includes:

[0225] The channel access parameters are determined based on whether the virtual collision metric meets the threshold.

[0226] 16. The method according to any one of clauses 1-14, wherein sending the first-side crosslink transmission based on the virtual collision metric comprises:

[0227] The first side link transmission is sent based on the virtual collision metric meeting the threshold.

[0228] 17. The method according to any one of clauses 1-16, wherein sending the first-side crosslink transmission based on the virtual collision metric comprises:

[0229] Based on congestion control, a second resource is selected from the sidelink resource pool for transmission on the first sidelink; and

[0230] Based on the configuration, it is determined that the congestion control will be performed using the virtual conflict metric.

[0231] 18. The method according to Clause 17, wherein the configuration includes an indication of whether the congestion control is permitted using the virtual conflict metric.

[0232] 19. The method according to Clause 17, wherein the configuration includes an indication for allowing the congestion control to be performed using the virtual conflict metric based on at least one of: the UE's capabilities, the area associated with the UE, the time period associated with the congestion control, or the detection of a RAT different from the UE's Radio Access Technology (RAT).

[0233] 20. The method according to any one of clauses 1-19 further comprises:

[0234] Send a report to the base station (BS) indicating the virtual conflict metric.

[0235] 21. The method according to Clause 20, wherein sending a report on the virtual conflict metric is further based on a reporting period.

[0236] 22. The method according to Clause 20, wherein sending a report on the virtual conflict metric is further triggered based on the report.

[0237] 23. A method for wireless communication performed by a user equipment (UE), the method comprising:

[0238] Perform measurement-only sensing in the sidelink resource pool, wherein performing the measurement-only sensing includes:

[0239] Select multiple measurement-only resources from the sidelink resource pool; and

[0240] To obtain the availability of the plurality of measurable resources; and

[0241] The first side link transmission is sent based on a virtual conflict metric associated with the availability of the plurality of measurement-only resources obtained from the measurement-only sensing.

[0242] 24. The method described according to Clause 23, wherein:

[0243] Obtaining the availability of the aforementioned multiple measurement-only resources includes:

[0244] A request is made to assess the availability of the aforementioned multiple measurable resources; and

[0245] Receive an indication that one or more of the plurality of measured resources are unavailable, wherein the virtual conflict metric is based on the number of the one or more unavailable resources.

[0246] 25. The method according to any one of clauses 23-24, wherein the performance of the measurement-only sensing is based on the measurement-only sensing configuration.

[0247] 26. The method according to Clause 25, wherein the measurement-only sensing configuration includes an indication of a period, and wherein the selection of the plurality of measurement-only resources is further based on the period.

[0248] 27. The method according to Clause 25, wherein the measurement-only sensing configuration includes indication of an event associated with at least one of a geographic region, a lost packet delay budget, or a virtual conflict metric threshold, and wherein the selection of the plurality of measurement-only resources is further based on the detection of said event.

[0249] 28. A user equipment (UE), comprising:

[0250] The processor is configured as follows:

[0251] Select multiple resources from the sidelink resource pool;

[0252] Request an assessment of the availability of the aforementioned resources; and

[0253] Receive an indication of the availability of the plurality of resources; and

[0254] A transceiver, communicating with the processor, is configured to:

[0255] The first side link transmission is sent based on a virtual conflict metric associated with the indication of availability of the plurality of resources.

[0256] 29. The UE as described in Clause 28, wherein:

[0257] The processor, configured to receive the indication of availability of the plurality of resources, is further configured to:

[0258] Receive an indication that one or more of the plurality of resources are unavailable; and

[0259] The virtual conflict metric is determined based on the indication that one or more of the resources are unavailable.

[0260] 30. A user equipment (UE), comprising:

[0261] The processor is configured as follows:

[0262] The measurement-only sensing is performed in the sidelink resource pool, wherein the processor configured to perform the measurement-only sensing is further configured to:

[0263] Select multiple measurement-only resources from the sidelink resource pool; and

[0264] To obtain the availability of the plurality of measurable resources; and

[0265] A transceiver, communicating with the processor, is configured to:

[0266] The first side link transmission is sent based on a virtual conflict metric associated with the availability of the plurality of measurement-only resources obtained from the measurement-only sensing.

[0267] Information and signals can be represented using any of a variety of different techniques and methods. For example, the data, instructions, commands, information, signals, bits, symbols, and chips mentioned in all of the above descriptions can be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or optical particles, or any combination thereof.

[0268] The various illustrative boxes and modules described in connection with the disclosure herein can be implemented or executed using a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware component, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration).

[0269] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions can be stored as one or more instructions or code on or transmitted through a computer-readable medium. Other examples and implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functions described above can be implemented using software executed by a processor, hardware, firmware, hardwired, or any combination thereof. Features implementing the functions can also be physically located in various locations, including portions distributed such that the functions are implemented at different physical locations. Furthermore, as used herein (including the claims), "or" as used in a list of items (e.g., a list of items ending with phrases such as "at least one of" or "one or more of") indicates an inclusive list, such that a list such as [at least one of A, B, or C] means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

[0270] As those skilled in the art will understand to date and depending on the specific application at hand, many modifications, substitutions, and variations can be made to the materials, apparatus, configuration, and methods of use of the devices disclosed herein without departing from the spirit and scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the specific embodiments shown and described herein, as they are merely examples, but should be fully commensurate with the scope of the appended claims and their functional equivalents.

Claims

1. A method for wireless communication performed by a user equipment (UE), the method comprising: Based on a first measurement of the availability of resources in the sidelink resource pool at a first time, multiple resources are selected from the sidelink resource pool; At a second time point following the first time point, a second measurement of the availability of the selected multiple resources is performed; Based on the second measurement, a first virtual conflict indication is stored in a virtual conflict log, the virtual conflict log including multiple virtual conflict indications; Based on a time window, a filter is applied to the virtual conflict log to provide a filtered virtual conflict metric. as well as Based on the filtered virtual collision metric, a first-side link transmission is sent using transmission parameters and resources that are different from the selected plurality of resources.

2. The method according to claim 1, wherein, Applying the filter to the virtual conflict log includes: Determine the number of virtual conflicts that occur within the time window.

3. The method according to claim 1, wherein, The first of the multiple resources is a measurement-only resource.

4. The method according to claim 1, wherein, Selecting the multiple resources includes: The first resource and the second resource are selected from the plurality of resources based on a resource selection trigger. The first resource is a measurement-only resource, and the second resource is a transmission resource to be used for transmission on the first side of the crosslink.

5. The method according to claim 4, wherein, Also includes: Send a first evaluation request for the measured-only resource at the first moment; as well as A second evaluation request for the second resource is sent at a second time, which is different from the first time.

6. The method according to claim 1, wherein, Sending the first-side cross-link transmission based on the filtered virtual collision metric further includes: The channel access parameters for the first-side crosslink transmission are determined based on the filtered virtual collision metric.

7. The method according to claim 6, wherein, The channel access parameter is the transmit power used for the first-side crosslink transmission.

8. The method according to claim 6, wherein, The channel access parameter is the maximum number of retransmissions.

9. The method according to claim 6, wherein, The channel access parameter is the contention window size.

10. The method according to claim 6, wherein, The channel access parameters are congestion control parameters.

11. The method according to claim 6, wherein, Determining the channel access parameters includes: The channel access parameters are determined based on whether the virtual conflict log recording period meets the threshold.

12. The method according to claim 6, wherein, Determining the channel access parameters includes: The channel access parameters are determined based on the number of resources selected for determining the filtered virtual conflict metric that meet a threshold.

13. The method according to claim 6, wherein, Determining the channel access parameters includes: The channel access parameters are determined based on whether the filtered virtual collision metric meets a threshold.

14. The method according to claim 1, wherein, Sending the first-side cross-link transmission includes: The first side link transmission is sent based on the filtered virtual collision metric meeting a threshold.

15. The method according to claim 1, wherein, Sending the first-side cross-link transmission includes: Based on congestion control, a second resource is selected from the sidelink resource pool for transmission on the first sidelink; and Based on the configuration, it is determined that the congestion control will be performed using the filtered virtual conflict metric.

16. The method according to claim 15, wherein, The configuration includes an indication of whether congestion control is permitted using the filtered virtual conflict metric.

17. The method according to claim 15, wherein, The configuration includes an indication that allows the congestion control to be performed using the filtered virtual conflict metric based on at least one of the following: the UE's capabilities, the region associated with the UE, the time period associated with the congestion control, or the detection of a RAT that is different from the UE's Radio Access Technology (RAT).

18. The method of claim 1, further comprising: Send a report to the base station (BS) indicating the filtered virtual collision metric.

19. The method according to claim 18, wherein, Reports on the filtered virtual conflict metrics are sent on a further periodic basis.

20. The method according to claim 18, wherein, Sending reports on the filtered virtual conflict metrics is further triggered based on these reports.

21. A method for wireless communication performed by a user equipment (UE), the method comprising: Based on a first measurement of the availability of resources in the sidelink resource pool at a first time, a plurality of measurement-only resources are selected from the sidelink resource pool; as well as At a second time following the first time, a second measurement is performed on the availability of the selected plurality of measurable resources; Based on the second measurement, a first virtual conflict indication is stored in a virtual conflict log, the virtual conflict log including multiple virtual conflict indications; Based on a time window, a filter is applied to the virtual conflict log to provide a filtered virtual conflict metric. as well as Based on the filtered virtual collision metric, a first-side link transmission is sent using transmission parameters and resources that are different from the selected plurality of measured resources.

22. The method according to claim 21, wherein, The first measurement is performed based on a measurement-only sensing configuration.

23. The method according to claim 22, wherein, The measurement-only sensing configuration includes an indication of a period, and wherein the selection of the plurality of measurement-only resources is further based on the period.

24. The method according to claim 22, wherein, The measurement-only sensing configuration includes indication of an event associated with at least one of a geographic region, a lost packet delay budget, or a virtual conflict metric threshold, wherein the selection of the plurality of measurement-only resources is further based on the detection of the event.

25. The method according to claim 21, wherein, Applying the filter to the virtual conflict log includes: Determine the number of virtual conflicts that occur within the time window.

26. The method according to claim 21, wherein, Selecting the multiple measurement-only resources includes: The first resource among the plurality of measured resources is selected based on a resource selection trigger. It also includes: selecting a second resource, which is a transmission resource to be used for transmission on the first side crosslink.

27. The method according to claim 26, wherein, Also includes: Send a first evaluation request for the first resource at the first moment; as well as A second evaluation request for the second resource is sent at a second time, which is different from the first time.

28. The method according to claim 21, wherein, Sending the first-side cross-link transmission includes: The first side link transmission is sent based on the filtered virtual collision metric meeting a threshold.

29. A user equipment (UE), comprising: One or more transceivers; One or more memory units; One or more processors coupled to the one or more transceivers and the one or more memories, the one or more memories storing instructions that can be executed by the one or more processors individually or in any combination to cause the UE to perform the following operations: Based on a first measurement of the availability of resources in the sidelink resource pool at a first time, multiple resources are selected from the sidelink resource pool; At a second time point following the first time point, a second measurement of the availability of the selected multiple resources is performed; Based on the second measurement, a first virtual conflict indication is stored in a virtual conflict log, the virtual conflict log including multiple virtual conflict indications; Based on a time window, a filter is applied to the virtual conflict log to provide a filtered virtual conflict metric. as well as Based on the filtered virtual collision metric, a first-side link transmission is sent using transmission parameters and resources that are different from the selected plurality of resources.

30. A user equipment (UE), comprising: One or more transceivers; One or more memory units; One or more processors coupled to the one or more transceivers and the one or more memories, the one or more memories storing instructions that can be executed by the one or more processors individually or in any combination to cause the UE to perform the following operations: Based on a first measurement of the availability of resources in the sidelink resource pool at a first time, a plurality of measurement-only resources are selected from the sidelink resource pool; as well as At a second time following the first time, a second measurement is performed on the availability of the selected plurality of measurable resources; Based on the second measurement, a first virtual conflict indication is stored in a virtual conflict log, the virtual conflict log including multiple virtual conflict indications; Based on a time window, a filter is applied to the virtual conflict log to provide a filtered virtual conflict metric. as well as Based on the filtered virtual collision metric, a first-side link transmission is sent using transmission parameters and resources that are different from the selected plurality of measured resources.

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