Method and apparatus for congestion control for NR V2X

Abstract

In one aspect, a method of wireless communication includes determining, by a user equipment (UE), a channel busy rate (CBR) window for a CBR measurement for one or more resources; determining, by the UE, CBR measurements for the CBR window and for the one or more resources; determining, by the UE, a channel occupancy (CR) window based on a first number of subframes used for a history of past transmissions, and based on a second number of subframes used for future planned transmissions and corresponding retransmissions; and determining, by the UE, a CR value for the CR window based on the sub-channels used for the one or more resources for the first number of subframes, and based on the sub-channels estimated for the one or more resources for the second number of subframes. In another aspect, a method includes determining a CR window based on CBR measurements.

Description

[0001] This application is a divisional application of the application filed on March 28, 2022, with application number 202080068008.5 and invention title "Method and apparatus for congestion control for NR V2X".

[0002] Cross-reference to related applications

[0003] This application claims the benefit of the following applications: U.S. Patent Application No. 17 / 061,543, titled "CONGESTION CONTROL FOR NR V2X", filed on October 1, 2020, and U.S. Provisional Patent Application No. 62 / 911,106, titled "CONGESTION CONTROL FOR NR V2X", filed on October 4, 2019. The entire contents of the above two applications are hereby incorporated by reference in their entirety. Technical field

[0004] Broadly speaking, aspects of the present disclosure relate to wireless communication systems, and more specifically, aspects of the present disclosure relate to managing device-to-device communication, such as congestion control for vehicle-to-everything (V2X) in new radio (NR). Background art

[0005] Wireless communication networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcasting, etc. These wireless networks can be multi-access networks capable of supporting multiple user devices (UEs). Such networks (which are typically multi-access networks) support communication for multiple users by sharing available network resources. An example of such a network is the Universal Terrestrial Radio Access Network (UTRAN). The UTRAN is a radio access network (RAN) defined as part of the Universal Mobile Telecommunications System (UMTS) (third-generation (3G) mobile phone technology supported by the Third Generation Partnership Project (3GPP)). Examples of multi-access network formats include code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, and single-carrier FDMA (SC-FDMA) networks.

[0006] A wireless communication network may include several base stations or Node Bs capable of supporting communication for several user devices (UEs). The UEs can communicate with the base stations via the downlink and the uplink. The downlink (or forward link) refers to the communication link from the base station to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the base station.

[0007] A base station can transmit data and control information to a UE on the downlink, and / or can receive data and control information from the UE on the uplink. On the downlink, transmissions from the base station may encounter interference due to transmissions from neighboring base stations or from other radio frequency (RF) transmitters. On the uplink, transmissions from the UE may encounter interference from uplink transmissions of other UEs communicating with neighboring base stations or from other radio RF transmitters. Such interference may degrade the performance on both the downlink and the uplink.

[0008] Due to the continuous growth in the demand for mobile broadband access, as more UEs access long-distance wireless communication networks and more short-distance wireless systems are deployed in communities, the likelihood of interfering with and congesting the network increases. Research and development continue to advance wireless technologies (including multiple access technologies), not only to meet the growing demand for mobile broadband access, but also to enhance and improve the user experience of mobile communications. Summary of the Invention

[0009] The following outlines some aspects of the present disclosure to provide a basic understanding of the technologies discussed. This summary is not an exhaustive review of all the expected features of the present disclosure, and is neither intended to identify the key or important elements of all aspects of the present disclosure, nor to depict the scope of any or all aspects of the present disclosure. Its sole purpose is to present some concepts of one or more aspects of the present disclosure in a summary form as a prelude to the more detailed description that follows.

[0010] The described technologies relate to improved methods, systems, devices, and apparatuses for supporting enhanced congestion control processes for device-to-device communication (such as vehicle-to-everything (V2X) communication). Such congestion control can enable enhanced operation in next-generation wireless modes, such as improved aperiodic communication performance in fifth-generation wireless new radio. Thus, such technologies can improve reliability and throughput, reduce latency, and enable operation in the URLLC mode.

[0011] In one aspect of the present disclosure, a method of wireless communication includes: determining, by a user equipment (UE), a channel busy rate (CBR) window for CBR measurements for one or more resources; determining, by the UE, CBR measurement values for the CBR window and for the one or more resources; determining, by the UE, a channel occupancy rate (CR) window based on a first number of subframes used for historical past transmissions and based on a second number of subframes used for future scheduled transmissions and corresponding retransmissions; and determining, by the UE, a CR value for the CR window based on subchannels used for the one or more resources for the first number of subframes and based on subchannels estimated for the one or more resources for the second number of subframes.

[0012] In an additional aspect of the present disclosure, an apparatus configured for wireless communication is disclosed. The apparatus includes: means for determining, by a user equipment (UE), a channel busy rate (CBR) window for CBR measurements for one or more resources; means for determining, by the UE, CBR measurement values for the CBR window and for the one or more resources; means for determining, by the UE, a channel occupancy rate (CR) window based on a first number of subframes used for historical past transmissions and based on a second number of subframes used for future scheduled transmissions and corresponding retransmissions; and means for determining, by the UE, a CR value for the CR window based on subchannels used for the one or more resources for the first number of subframes and based on subchannels estimated for the one or more resources for the second number of subframes.

[0013] In an additional aspect of the present disclosure, a non-transitory computer-readable medium has program code recorded thereon. The program code includes code for performing the following operations: determining, by a user equipment (UE), a channel busy rate (CBR) window for CBR measurements for one or more resources; determining, by the UE, CBR measurement values for the CBR window and for the one or more resources; determining, by the UE, a channel occupancy rate (CR) window based on a first number of subframes used for historical past transmissions and based on a second number of subframes used for future scheduled transmissions and corresponding retransmissions; and determining, by the UE, a CR value for the CR window based on subchannels used for the one or more resources for the first number of subframes and based on subchannels estimated for the one or more resources for the second number of subframes.

[0014] In additional aspects of the present disclosure, an apparatus configured for wireless communication is disclosed. The apparatus includes: at least one processor; and a memory coupled to the processor. The processor is configured to: determine, by a user equipment (UE), a channel busy rate (CBR) window for CBR measurements for one or more resources; determine, by the UE, CBR measurement values for the CBR window and for the one or more resources; determine, by the UE, a channel occupancy rate (CR) window based on a first number of subframes used for historical transmissions in the past and based on a second number of subframes used for future scheduled transmissions and corresponding retransmissions; and determine, by the UE, a CR value for the CR window based on subchannels used for the one or more resources for the first number of subframes and based on subchannels estimated for the one or more resources for the second number of subframes.

[0015] The features and technical advantages of examples in accordance with the present disclosure have been outlined rather broadly above so that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter. The disclosed concepts and specific examples may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. The characteristics of the concepts disclosed herein, both as to their organization and method of operation, as well as associated advantages, will be better understood when considered in conjunction with the following description taken in connection with the accompanying drawings. Each of the drawings in the accompanying drawings is provided for purposes of illustration and description and is not to be construed as a definition of the limits of the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] A further understanding of the nature and advantages of the present disclosure may be realized by reference to the following drawings. In the drawings, like components or features may have the same reference numeral. Additionally, various components of the same type may be distinguished by following the reference numeral with a dash and a second numeral, which differentiates among similar components. If only the first reference numeral is used in the specification, the description may apply to any one of the similar components having the same first reference numeral without regard to the second reference numeral.

[0017] Figure 1 is a block diagram showing details of a wireless communication system.

[0018] Figure 2 is a block diagram showing the design of a base station and a UE configured in accordance with an aspect of the present disclosure.

[0019] Figure 3 is a diagram of a device-to-device communication system.

[0020] Figure 4It is an example diagram showing device-to-device communication.

[0021] Figure 5 It is a block diagram showing an example of a wireless communication system that implements enhanced congestion control for device-to-device communication according to aspects of the present disclosure.

[0022] Figure 6 It is a block diagram showing example blocks executed by a UE configured according to one aspect of the present disclosure.

[0023] Figure 7 It is a block diagram showing example blocks executed by a UE configured according to another aspect of the present disclosure.

[0024] Figure 8 It is a block diagram conceptually showing the design of a UE according to some embodiments of the present disclosure. Detailed Description

[0025] Some aspects of the present disclosure are outlined below to provide a basic understanding of the technologies discussed. This overview is not an exhaustive review of all the expected features of the present disclosure, and is neither intended to identify the key or important elements of all aspects of the present disclosure, nor to depict the scope of any or all aspects of the present disclosure. Its sole purpose is to present some concepts of one or more aspects of the present disclosure in an overview form as a prelude to the more detailed description that follows.

[0026] The detailed description is related to enhanced congestion control for device-to-device (D2D) communication. Traditionally, congestion control for D2D communication is based on both the usage history and the estimated usage for future transmissions. However, estimating future usage may not be reliable in all scenarios. For example, when using non-periodic communication, a device may not be able to accurately estimate its future usage or the usage of other devices and / or the medium. Accordingly, a UE may not be able to accurately determine congestion information and / or may not be able to effectively perform congestion control. For some operation modes (such as URLLC (e.g., eURLLC)), such a process may not be able to achieve high reliability and / or meet the low latency requirements or constraints.

[0027] The described techniques relate to improved methods, systems, devices, and apparatuses that support congestion control enhancements for D2D communication, including for non-periodic communication. For example, channel busy rate and channel occupancy rate calculations can be based on a more restricted estimate of possible future transmissions. For instance, in some implementations, the future window for congestion control estimation can be limited to currently scheduled non-periodic transmissions. Such enhanced congestion control enhancements can enable enhanced operation in D2D communication modes, such as for V2X NR. Accordingly, such techniques can improve reliability and throughput, reduce latency, and enable operation in the URLLC mode.

[0028] The detailed description set forth below in connection with the accompanying drawings is intended as a description of various configurations and is not intended to limit the scope of the present disclosure. Rather, for the purpose of providing a thorough understanding of the subject matter of the invention, the detailed description includes specific details. It will be apparent to those skilled in the art that these specific details are not required in every case and that, in some instances, well-known structures and components are shown in block diagram form for clarity of presentation.

[0029] Generally, the present disclosure relates to providing or participating in authorized shared access between two or more wireless communication systems (also referred to as wireless communication networks). In various embodiments, the techniques and apparatuses can be used in wireless communication networks and other communication networks such as the following: code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single carrier FDMA (SC-FDMA) networks, LTE networks, GSM networks, fifth generation (5G) or new radio (NR) networks. As described herein, the terms "network" and "system" can be used interchangeably.

[0030] OFDMA networks can implement radio technologies such as evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, Flash-OFDM, etc. UTRA, E-UTRA, and Global System for Mobile Communications (GSM) are part of the Universal Mobile Telecommunications System (UMTS). Specifically, Long-Term Evolution (LTE) is a version of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents provided by an organization named "3rd Generation Partnership Project" (3GPP), and cdma2000 is described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). These various radio technologies and standards are known or are under development. For example, the 3rd Generation Partnership Project (3GPP) is a cooperation among groups of telecommunications associations aimed at defining globally applicable third-generation (3G) mobile phone specifications. 3GPP Long-Term Evolution (LTE) is a 3GPP plan aimed at improving the Universal Mobile Telecommunications System (UMTS) mobile phone standard. 3GPP can define specifications for next-generation mobile networks, mobile systems, and mobile devices. The present disclosure relates to the evolution of wireless technologies from LTE, 4G, 5G, NR, and beyond, which have shared access to the radio spectrum between networks using a new and different set of radio access technologies or radio air interfaces.

[0031] Specifically, 5G networks are expected to enable diverse deployments, diverse spectrums, and diverse services and devices 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: (1) provide coverage for massive Internet of Things (IoT) with ultra-high density (e.g., ~1M nodes / km 2 ), ultra-low complexity (e.g., ~10s of bits / second), and ultra-low energy (e.g., ~10+ years of battery life), and provide deep coverage with the ability to reach challenging locations; (2) include mission-critical control with strong security for protecting sensitive personal, financial, or confidential information, ultra-high reliability (e.g., ~99.9999% reliability), ultra-low latency (e.g., ~1ms), and users with a wide range of mobility or lack of mobility; and (3) have enhanced mobile broadband, which includes extremely high capacity (e.g., ~10 Tbps / km 2 ), extreme data rates (e.g., multi-Gbps rates, 100+ Mbps user experience rate), and advanced discovery and optimized depth perception.

[0032] 5G NR can be implemented to use an optimized OFDM-based waveform with scalable numerology and transmission time intervals (TTIs); have a common flexible framework to efficiently multiplex services and features using dynamic low-latency time division duplexing (TDD) / frequency division duplexing (FDD) designs; and have advanced radio technologies such as massive multiple-input multiple-output (MIMO), robust millimeter wave (mmWave) transmission, advanced channel decoding, and device-centric mobility. The scalability of the numerology in 5G NR (with scaling of the subcarrier spacing) can efficiently address operating diverse services across diverse spectrums and diverse deployments. For example, in various outdoor and macro coverage deployments with less than 3 GHz FDD / TDD implementations, the subcarrier spacing can occur at 15 kHz for bandwidths such as 1, 5, 10, 20 MHz, etc. For various other outdoor and small cell coverage deployments with TDD greater than 3 GHz, the subcarrier spacing can occur at 30 kHz for 80 / 100 MHz bandwidths. For various other indoor broadband implementations using TDD in the unlicensed portion of the 5 GHz band, the subcarrier spacing can occur at 60 kHz for 160 MHz bandwidths. Finally, for various deployments transmitting using the millimeter wave component at 28 GHz TDD, the subcarrier spacing can occur at 120 kHz for 500 MHz bandwidths.

[0033] The scalable numerology of 5G NR contributes to scalable TTIs for different 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. The efficient multiplexing of long and short TTIs allows transmissions to start at symbol boundaries. 5G NR also anticipates a self-contained integrated subframe design where uplink / downlink scheduling information, data, and acknowledgments are in the same subframe. The self-contained integrated subframe supports communication in unlicensed or contention-based shared spectrums, adaptive uplink / downlink (which can be flexibly configured on a per-cell basis to dynamically switch between uplink and downlink to meet current traffic demands).

[0034] Various other aspects and features of the present disclosure are further described below. It should be apparent that the teachings herein can be embodied in a variety of forms, and that any particular structure, function, or both disclosed herein are merely representative and not restrictive. Based on the teachings herein, those of ordinary skill in the art should recognize that the aspects disclosed herein can be implemented independently of any other aspect, and that two or more of these aspects can be combined in various ways. For example, using any number of the aspects set forth herein, an apparatus can be implemented or a method can be practiced. In addition, such an apparatus can be implemented or such a method can be practiced using other structures, functions, or both other than and different from one or more of the 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. In addition, one aspect can include at least one element of a claim.

[0035] Figure 1 is a block diagram illustrating a 5G network 100 including various base stations and UEs configured according to aspects of the present disclosure. The 5G network 100 includes several base stations 105 and other network entities. A base station can be a station that communicates with a UE and can also be referred to as an evolved node (eNB), a next-generation eNB (gNB), an access point, etc. Each base station 105 can provide communication coverage for a specific geographic area. In 3GPP, the term "cell" can refer to this specific geographic coverage area of the base station and / or the base station subsystem serving the coverage area, depending on the context in which the term is used.

[0036] A base station can provide communication coverage for a macro cell or a small cell (such as a pico cell or a femto cell) and / or other types of cells. A macro cell typically covers a relatively large geographic area (e.g., with a radius of several kilometers) and can allow unrestricted access by UEs having a service subscription with the network provider. A small cell (such as a pico cell) typically will cover a relatively small geographic area and can allow unrestricted access by UEs having a service subscription with the network provider. A small cell (such as a femto cell) typically will also cover a relatively small geographic area (e.g., a residence) and, in addition to unrestricted access, can provide restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in a residence, etc.). A base station for a macro cell can be referred to as a macro base station. A base station for a small cell can be referred to as a small cell base station, a pico base station, a femto base station, or a home base station. In Figure 1In the example shown, base stations 105d and 105e are conventional macro base stations, while base stations 105a - 105c are macro base stations implemented using one of 3 - Dimensional (3D), Full - Dimensional (FD), or massive MIMO. Base stations 105a - 105c utilize their higher - dimensional MIMO capabilities to employ 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. Base station 105f is a small cell base station, which can be a home node or a portable access point. A base station can support one or more (e.g., two, three, four, etc.) cells.

[0037] The 5G network 100 can support synchronous operation or asynchronous operation. For synchronous operation, base stations can have similar frame timings, and transmissions from different base stations can be approximately aligned in time. For asynchronous operation, base stations can have different frame timings, and transmissions from different base stations can be misaligned in time.

[0038] UEs 115 are scattered throughout the wireless network 100, and each UE can be stationary or mobile. A UE can also be referred to as a terminal, mobile station, user unit, station, etc. A UE 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. In one aspect, a UE can be a device that includes a Universal Integrated Circuit Card (UICC). In another aspect, a UE can be a device that does not include a UICC. In some aspects, a UE that does not include a UICC can also be referred to as an Internet of Everything (IoE) or Internet of Things (IoT) device. UEs 115a - 115d are examples of mobile smart - phone - type devices accessing the 5G network 100. A UE can also be a machine specifically configured for connection - oriented communication (including Machine - Type Communication (MTC), Enhanced MTC (eMTC), Narrow - Band IoT (NB - IoT), etc.). UEs 115e - 115k are examples of various machines accessing the 5G network 100 that are configured for communication. A UE is capable of communicating with any type of base station, whether it is a macro base station, small cell, etc. In Figure 1 which, lightning (e.g., communication link) indicates a wireless transmission between a UE and a serving base station (which is the base station designated to serve the UE on the downlink and / or uplink), or a desired transmission between base stations, and a backhaul transmission between base stations.

[0039] In operation at 5G network 100, base stations 105a - 105c use 3D beamforming and coordinated spatial techniques (such as coordinated multipoint (CoMP) or multi - connection) to serve UEs 115a and 115b. Macro base station 105d performs backhaul communication with base stations 105a - 105c and small cell base station 105f. Macro base station 105d also sends multicast services subscribed to and received by UEs 115c and 115d. Such multicast services can include mobile TV or streaming video, or can include other services for providing community information, such as weather emergencies or alerts (such as Amber alerts or Gray alerts).

[0040] 5G network 100 also supports mission - critical communication with ultra - reliable and redundant links for mission - critical devices (such as UE 115e, which is a drone). The redundant communication links with UE 115e include those from macro base stations 105d and 105e and small cell base station 105f. Other machine - type devices (such as UE 115f (a thermometer), UE 115g (a smart meter), and UE 115h (a wearable device)) can communicate directly with base stations (such as small cell base station 105f and macro base station 105e) via 5G network 100, or in a multi - hop configuration where they communicate by relaying their information to another user equipment that relays it to the network (such as UE 115f transmits temperature measurement information to the smart meter (UE 115g), and the temperature measurement information is then reported to the network via small cell base station 105f). 5G network 100 can also provide additional network efficiency via dynamic low - latency TDD / FDD communication (such as in a vehicle - to - vehicle (V2V) mesh network between UEs 115i - 115k communicating with macro base station 105e).

[0041] Figure 2 Base stations 105 and UEs 115 are shown, which can be Figure 1Block diagram of the design of one base station in the base stations and one UE in the UEs). At base station 105, transmit processor 220 may receive data from data source 212 and control information from controller / processor 240. The control information may be used for PBCH, PCFICH, PHICH, PDCCH, EPDCCH, MPDCCH, etc. The data may be used for PDSCH, etc. Transmit processor 220 may process (e.g., encode and symbol map) the data and control information respectively to obtain data symbols and control symbols. Transmit processor 220 may also generate reference symbols such as for PSS, SSS, and cell-specific reference signals. Transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, control symbols, and / or reference symbols (if applicable), and may provide an output symbol stream to modulators (MOD) 232a to 232t. Each modulator 232 may process the corresponding output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 232 may further process (e.g., transform to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The downlink signals from modulators 232a to 232t may be transmitted via antennas 234a to 234t respectively.

[0042] At UE 115, antennas 252a to 252r may receive the downlink signals from base station 105, and may provide the received signals to demodulators (DEMOD) 254a to 254r respectively. Each demodulator 254 may condition (e.g., filter, amplify, down-convert, and digitize) the corresponding received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. MIMO detector 256 may obtain the received symbols from all demodulators 254a to 254r, perform MIMO detection on the received symbols (if applicable), and provide the detected symbols. Receive processor 258 may process (e.g., demodulate, de-interleave, and decode) the detected symbols, provide the decoded data for UE 115 to data sink 260, and provide the decoded control information to controller / processor 280.

[0043] On the uplink, at the UE 115, the transmit processor 264 may receive and process data from the data source 262 (e.g., for PUSCH) and control information from the controller / processor 280 (e.g., for PUCCH). The transmit processor 264 may also generate reference symbols for reference signals. The symbols from the transmit processor 264 may be precoded by the TX MIMO processor 266 (if applicable), further processed by the modulators 254a through 254r (e.g., for SC-FDM, etc.), and transmitted to the base station 105. At the base station 105, the uplink signals from the UE 115 may be received by the antenna 234, processed by the demodulator 232, detected by the MIMO detector 236 (if applicable), and further processed by the receive processor 238 to obtain the decoded data and control information transmitted by the UE 115. The processor 238 may provide the decoded data to the data sink 239 and the decoded control information to the controller / processor 240.

[0044] The controller / processors 240 and 280 may direct operations at the base station 105 and the UE 115, respectively. The controller / processor 240 and / or other processors and modules at the base station 105 may perform or direct the execution of various processes for the techniques described herein. The controller / processor 280 and / or other processors and modules at the UE 115 may also perform or direct the execution of the functional blocks shown in Figure 6 and Figure 7 and / or other processes for the techniques described herein. The memories 242 and 282 may store data and program codes for the base station 105 and the UE 115, respectively. The scheduler 244 may schedule the UE for data transmission on the downlink and / or uplink.

[0045] Wireless communication systems operated by different network operating entities (e.g., network operators) may share spectrum. In some instances, a network operating entity may be configured to use the entire designated shared spectrum for at least a period of time before another network operating entity uses the entire designated shared spectrum during a different period of time. Thus, to allow network operating entities to use the full designated shared spectrum and to mitigate interfering communications between different network operating entities, certain resources (e.g., time) may be partitioned and allocated to different network operating entities for certain types of communications.

[0046] For example, certain time resources can be allocated to a network operating entity, and these time resources are reserved for exclusive communication by the network operating entity using the entire shared spectrum. Other time resources can also be allocated to the network operating entity, in which the entity is given a higher priority than other network operating entities to use the shared spectrum for communication. If the prioritized network operating entity does not use these resources, these time resources prioritized for use by the network operating entity can be used by other network operating entities on an opportunistic basis. Additional time resources can be allocated for any network operator to use on an opportunistic basis.

[0047] The access to the shared spectrum and the arbitration of time resources among different network operating entities can be centrally controlled by a separate entity, determined autonomously by a predefined arbitration scheme, or determined dynamically based on the interaction among the wireless nodes of the network operator.

[0048] In some cases, the UE 115 and the base station 105 of the 5G network 100 (in Figure 1 ) can operate in a shared radio frequency spectrum band, which can include licensed or unlicensed (e.g., contention-based) spectrum. In the unlicensed frequency portion of the shared radio frequency spectrum band, the UE 115 or the base station 105 can traditionally perform a medium sensing process to compete for access to the spectrum. For example, the UE 115 or the base station 105 can perform a listen-before-talk (LBT) process (such as a clear channel assessment (CCA)) before communication to determine whether the shared channel is available. The CCA can include an energy detection process to determine whether there are any other active transmissions. For example, the device can infer that a change in the received signal strength indicator (RSSI) of the power meter indicates that the channel is occupied. Specifically, the signal power concentrated in a certain bandwidth and exceeding a predetermined background noise can indicate another wireless transmitter. The CCA can also include the detection of a specific sequence indicating the use of the channel. For example, another device can send a specific preamble before sending a data sequence. In some cases, the LBT process can include: the wireless node adjusts its own backoff window based on the amount of energy detected on the channel and / or the acknowledgment / negative acknowledgment (ACK / NACK) feedback for the packet sent by itself as a proxy for contention.

[0049] Generally, four categories of LBT procedures have been proposed to sense a shared channel for signals that may indicate the channel is occupied. In the first category (CAT 1 LBT), no LBT or CCA is applied to detect occupancy of the shared channel. The second category (CAT 2 LBT) (which may also be referred to as shortened LBT, single-shot LBT, or 25-μs LBT) provides for a node to perform CCA to detect energy above a predetermined threshold or to detect a message or preamble that occupies the shared channel. CAT 2 LBT performs CCA without using a random backoff operation, which results in its shortened length relative to the next category.

[0050] The third category (CAT 3 LBT) performs CCA to detect energy or messages on the shared channel, but also uses random backoff and a fixed contention window. Thus, when a node initiates CAT 3 LBT, it performs a first CCA to detect occupancy of the shared channel. If the shared channel is idle during the duration of the first CCA, the node may continue to transmit. However, if the first CCA detects a signal that occupies the shared channel, the node selects a random backoff based on the fixed contention window size and performs an extended CCA. If the shared channel is detected to be idle during the extended CCA and the random number has decremented to 0, the node may start transmission on the shared channel. Otherwise, the node decrements the random number and performs another extended CCA. The node will continue to perform extended CCA until the random number reaches 0. If the random number reaches 0 without detecting channel occupancy in any extended CCA, the node may then transmit on the shared channel. If at any extended CCA the node detects channel occupancy, the node may re-select a new random backoff based on the fixed contention window size to start counting down again.

[0051] The fourth category (CAT 4 LBT) (which may also be referred to as the full LBT procedure) performs CCA using energy or message detection with random backoff and a variable contention window size. The sequence of CCA detections proceeds similarly to the process of CAT 3 LBT, except that the contention window size is variable for the CAT 4 LBT procedure.

[0052] Using a medium sensing procedure to compete for access to unlicensed shared spectrum can result in communication inefficiencies. This can be particularly evident when multiple network operating entities (e.g., network operators) are attempting to access the shared resource. In a 5G network 100, the base station 105 and the UE 115 can be operated by the same or different network operating entities. In some examples, a single base station 105 or UE 115 can be operated by more than one network operating entity. In other examples, each base station 105 and UE 115 can be operated by a single network operating entity. Requiring each base station 105 and UE 115 of different network operating entities to compete for the shared resource can result in increased signaling overhead and communication latency.

[0053] Figure 3 is a diagram of a device-to-device (D2D) communication system 360. The D2D communication system 360 includes multiple UEs 364, 366, 368, 370. The D2D communication system 360 can overlap with a cellular communication system (such as, for example, a WWAN). Some of the UEs 364, 366, 368, 370 can communicate with each other using the DL / UL WWAN spectrum in D2D communication, some UEs can communicate with the base station 362, and some UEs can perform both operations. For example, as Figure 3 shown, UEs 368, 370 are in D2D communication, and UEs 364, 366 are in D2D communication. UEs 364, 366 also communicate with the base station 362. D2D communication can be through one or more sidelink channels, such as the Physical Sidelink Broadcast Channel (PSBCH), the Physical Sidelink Discovery Channel (PSDCH), the Physical Sidelink Shared Channel (PSSCH), and the Physical Sidelink Control Channel (PSCCH).

[0054] The exemplary methods and apparatus discussed below are applicable to any of a variety of wireless D2D communication systems, such as, for example, wireless device-to-device communication systems based on the following: NR, LTE, FlashLinQ, WiMedia, Bluetooth, ZigBee, or Wi-Fi based on the IEEE 802.11 standard. For simplicity of discussion, the exemplary methods and apparatus are discussed in the context of NR. However, those of ordinary skill in the art will understand that the exemplary methods and apparatus are more generally applicable to a variety of other wireless device-to-device communication systems.

[0055] D2D communication can be used to provide direct communication between devices. D2D communication enables a device to communicate with another device and send data to the other device over allocated resources. One use case for D2D communication is vehicle-to-vehicle (V2V) communication and vehicle-to-everything (V2X) communication. Thus, according to V2V communication, a device of a first vehicle can perform D2D communication with a device of another vehicle. According to V2X communication, a device of a vehicle can perform D2D communication with another device regardless of whether the device resides in a vehicle.

[0056] One type of communication that can be used for V2V communication is dedicated short-range communication (DSRC). DSRC is a short-range wireless communication capability typically based on IEEE 802.11p similar to Wi-Fi. In DSRC, a device can check the channel before transmission. For traffic-related communication (e.g., V2X communication), the 5.9 GHz unlicensed spectrum is typically reserved to transmit intelligent transportation services (ITS). Recently, implementing other types of communication such as NR communication for V2V communication has been under development. For example, NR D2D can be used for V2V communication over licensed spectrum and / or unlicensed spectrum.

[0057] In a vehicle-to-everything (V2X) wireless communication system, a UE can directly communicate using device-to-device communication (also known as sidelink communication) without using a network entity (e.g., a base station) as an intermediary. In some cases, a UE can operate using a specific transmission mode such as transmission mode 4, where resource selection and / or scheduling is performed by the UE rather than a network entity (e.g., a base station). In some aspects, a UE can perform resource selection and / or scheduling by measuring one or more sidelink channels, by decoding sidelink control information (SCI) indicating channel availability, by determining the channel busy rate (CBR) associated with various sidelink channels, etc.

[0058] In transmission mode 4, a UE can generate a sidelink grant and can send the sidelink grant in the SCI. The sidelink grant can indicate, for example, one or more parameters (e.g., transmission parameters) to be used for an upcoming V2X transmission (e.g., V2X data transmission), such as one or more resource blocks to be used for the upcoming V2X transmission, one or more subframes to be used for the upcoming V2X transmission, the modulation and coding scheme (MCS) to be used for the upcoming V2X transmission, etc.

[0059] In a V2X communication system, the conditions of the sidelink channels used to carry V2X communications can vary greatly and change rapidly due to the high mobility of vehicles and UEs associated with the vehicles, the large variations in vehicle traffic at different times of the day and at different locations, the various terrains that vehicles may traverse (e.g., dense urban environments, hilly environments, flat environments, etc.), and so on. Additionally, due to mission-critical safety issues associated with, for example, autonomous vehicles, the V2X communication system needs to be highly reliable. Some of the techniques and apparatuses described herein improve the performance of the V2X communication system by dynamically determining parameters for V2X transmissions based at least in part on dynamic factors associated with one or more vehicles, sidelink channels, etc.

[0060] In some aspects, the V2X transmission can be a one-to-many broadcast and / or multicast transmission. In some aspects, the V2X transmission may not require any physical layer feedback from the receiving device, such as acknowledgement (ACK) or negative acknowledgement (NACK) feedback. In some aspects, the V2X transmission can be configured to not have retransmissions. In some aspects, the V2X transmission can be configured to have several retransmissions (e.g., five retransmissions). In certain aspects, the retransmissions occur automatically, such as in the absence of ACK / NACK feedback.

[0061] A first UE can communicate with a second UE (and one or more other UEs) using device-to-device (D2D) communication via one or more sidelink channels. In some aspects, the UE can correspond to one or more of the other UEs described elsewhere herein. The UE can use the sidelink channels to send V2X communications.

[0062] The sidelink channel may include the PSCCH and the PSSCH. The sidelink channel may optionally include a Physical Sidelink Feedback Channel (PSFCH). The PSCCH may be used to transmit control information, similar to the Physical Downlink Control Channel (PDCCH) and / or the Physical Uplink Control Channel (PUCCH) used for communication with a base station. The PSSCH may be used to transmit data, similar to the Physical Downlink Shared Channel (PDSCH) and / or the Physical Uplink Shared Channel (PUSCH) used for communication with a base station. For example, the PSCCH may carry sidelink control information (SCI), and the SCI may indicate various control information for sidelink communication, such as one or more resources (e.g., time resources and / or frequency resources), where a transport block (TB) including data is carried on the PSSCH. The TB may include V2X data, such as a Basic Safety Message (BSM), a Traffic Information Message (TIM), a Signal Phase and Time (SPAT) message, a MAP message for transmitting geographical road information, a Cooperative Awareness Message (CAM), a Distributed Environmental Notification Message (DENM), an In-Vehicle Information (IVI) message, etc.

[0063] In some aspects, the sidelink channel may use a resource pool. For example, a specific resource block (RB) across time may be used to send a scheduling assignment (e.g., included in the SCI) in a subchannel. In some aspects, the data transmission associated with the scheduling assignment (e.g., on the PSSCH) may occupy adjacent RBs in the same subframe as the scheduling assignment (e.g., using frequency division multiplexing). In some aspects, the scheduling assignment and the associated data transmission are not sent on adjacent RBs.

[0064] In some aspects, the UE may operate using transmission mode 4, where resource selection and / or scheduling is performed by the UE (e.g., rather than the base station). In some aspects, the UE may perform resource selection and / or scheduling by sensing the channel availability for transmission. For example, the UE may measure the Received Signal Strength Indicator (RSSI) parameter associated with various sidelink channels (e.g., the sidelink RSSI (S-RSSI) parameter), may measure the Reference Signal Received Power (RSRP) parameter associated with various sidelink channels (e.g., the PSSCH-RSRP parameter), may measure the Reference Signal Received Quality (RSRQ) parameter associated with various sidelink channels (e.g., the PSSCH-RSRQ parameter), etc., and may select a channel for V2X communication transmission at least partially based on the measurements.

[0065] Additionally or alternatively, the UE may use the SCI received in the PSCCH to perform resource selection and / or scheduling, where the SCI may indicate occupied resources, channel parameters, etc. Additionally or alternatively, the UE may perform resource selection and / or scheduling by determining the channel busy rate (CBR) associated with various sidelink channels, and the channel busy rate may be used for rate control (e.g., by indicating the maximum number of resource blocks that the UE may use for a particular set of subframes).

[0066] In transmission mode 4, the UE may generate a sidelink grant and may send the grant in the SCI. The sidelink grant may indicate, for example, one or more parameters (e.g., transmission parameters) to be used for an upcoming V2X transmission, such as one or more resource blocks to be used for an upcoming V2X transmission on the PSSCH (e.g., for a TB), one or more subframes to be used for an upcoming V2X transmission, the modulation and coding scheme (MCS) to be used for an upcoming V2X transmission, etc. In some aspects, the UE may generate a sidelink grant indicating one or more parameters for semi-persistent scheduling (SPS) (such as the periodicity of V2X transmissions (e.g., periodic V2X messages, such as safety messages, etc.)). Additionally or alternatively, the UE may generate a sidelink grant for event-driven scheduling (such as for on-demand V2X messages).

[0067] In a V2X communication system, the conditions of the sidelink channels used to carry V2X communications may vary greatly and change rapidly due to the high mobility of vehicles and UEs associated with the vehicles, the large variations in vehicle traffic at different times of the day and in different locations, the various terrains that vehicles may cross (e.g., dense urban environments, hilly environments, flat environments, etc.), etc. Additionally, due to mission-critical safety issues associated with, for example, autonomous vehicles, the V2X communication system needs to be highly reliable. Some of the techniques and apparatuses described herein improve the performance of the V2X communication system by dynamically determining parameters for V2X transmissions based at least in part on dynamic factors associated with one or more vehicles, sidelink channels, etc.

[0068] In some implementations, in accordance with various aspects of the present disclosure, the UE may be capable of performing autonomous resource selection for V2X transmissions.

[0069] For example, the UE may determine a limit on the number of resource blocks (RBs) allowed for V2X transmissions performed by the UE. In some aspects, the UE may determine the limit at least in part based on the congestion level of one or more sidelink channels, which may be determined at least in part based on measuring one or more sidelink channels (e.g., for S-RSSI, PSSCH-RSRP, etc.), receiving SCI associated with one or more sidelink channels, etc. For example, the UE may determine the channel busy rate (CBR) for a sidelink channel (e.g., CBR(n-100,n-1), where n-100 represents the start of the time period and n-1 represents the end of the time period) associated with the time n at which resource selection is triggered for the UE, and may determine the maximum number of RBs allowed for the UE to use at time n at least in part based on the CBR. Additionally or alternatively, the UE may determine the limit on the number of RBs by determining the maximum number of RBs allowed for the UE to use (e.g., CRlimit(n)) associated with time n and subtracting the number of RBs that have been used or scheduled by the UE associated with time n (e.g., CR(n-a,n+b), where n-a represents the start of the time period and n+b represents the end of the time period).

[0070] The UE may determine one or more parameters for V2X transmissions at least in part based on the limit on the number of RBs. In some aspects, the one or more parameters may be referred to as one or more transmission parameters and / or one or more V2X transmission parameters. As shown, the one or more parameters may include the modulation and coding scheme (MCS) for V2X transmissions, the number of transport blocks (TBs) for V2X transmissions, the number of RBs per TB for V2X transmissions, the retransmission configuration for V2X transmissions, etc. In some aspects, the UE may determine the one or more parameters such that the number of RBs for V2X transmissions does not exceed the limit on the number of RBs.

[0071] As an example, if the UE selects an MCS with a lower index value (e.g., allowing fewer bits per symbol) for V2X transmission, then compared to using an MCS with a higher index value (e.g., allowing more bits per symbol) for the same V2X transmission, that V2X transmission will require more TBs and corresponding RBs. However, compared to using an MCS with a higher index value, using an MCS with a lower index value for V2X transmission can increase the range of the V2X transmission and / or can improve the reliability of the V2X transmission. Thus, in some aspects, if the limit on the number of RBs is relatively high (e.g., greater than or equal to a threshold), then the UE can select an MCS with a lower index value, and if the limit on the number of RBs is relatively low (e.g., less than or equal to a threshold), then the UE can select an MCS with a higher index value. In some aspects, the UE can select from multiple different MCS index values, and different MCS index values can be associated with different thresholds for the limit on the number of RBs.

[0072] As another example, if the UE configures a retransmission configuration to enable retransmission for V2X transmission, then compared to if the UE configures a retransmission configuration to disable retransmission for the same V2X transmission, the V2X transmission will require more TBs and corresponding RBs. However, compared to disabling retransmission for V2X transmission, enabling retransmission for V2X transmission can increase the range of the V2X transmission and / or can improve the reliability of the V2X transmission. Thus, in some aspects, if the limit on the number of RBs is relatively high (e.g., greater than or equal to a threshold), then the UE can enable retransmission, and if the limit on the number of RBs is relatively low (e.g., less than or equal to a threshold), then the UE can disable retransmission. In some aspects, the UE can select from multiple different numbers of retransmissions (e.g., one retransmission, two retransmissions, etc.), and different numbers of retransmissions can be associated with different thresholds for the limit on the number of RBs.

[0073] In some aspects, the UE can select one or more parameters to increase or maximize the range of the V2X transmission that complies with the limit on the number of RBs (e.g., the distance that the V2X transmission and corresponding retransmissions can cover), as described in more detail below in conjunction with Figure 5 This way, the UE can improve reliability, can increase security, can increase the likelihood of successfully receiving the V2X transmission, etc., while operating according to the limit on the number of RBs allowed for V2X transmission.

[0074] In a V2X communication system, the sidelink channel conditions can vary significantly at different times, at different geographical locations, at different frequencies, etc. Thus, a UE can dynamically determine one or more parameters for V2X transmission based at least in part on the conditions present when scheduling the V2X transmission. In some aspects, a UE can determine one or more transmission parameters based at least in part on dynamic factors associated with the UE and / or a vehicle associated with the UE (e.g., network traffic demands, congestion, etc. associated with one or more applications of the UE). Additionally or alternatively, a UE can determine one or more transmission parameters based at least in part on dynamic factors associated with the radio network over which the V2X transmission is to be sent (e.g., congestion level associated with the radio network, carrier frequency on which the V2X transmission is to be sent, priority of V2X transmissions on the radio network, etc.). In this way, the UE can improve or optimize the transmission of V2X messages in varying conditions.

[0075] Additionally or alternatively, a UE can determine one or more V2X transmission parameters based at least in part on one or more selected frequencies. For example, different frequencies can be associated with different CBR values and thus can be associated with different limits on the number of RBs allowed for use by the UE. Additionally or alternatively, different combinations of transmission parameters can result in different performance at different frequencies, and the UE can use this as a factor when determining one or more transmission parameters.

[0076] In some aspects, a UE can determine one or more transmission parameters based at least in part on network traffic demands associated with one or more applications of the UE. For example, if a first UE has relatively high network traffic demands (e.g., the number of requested V2X transmissions is greater than or equal to a threshold), the UE can use a smaller number of RBs per V2X transmission. Conversely, if the UE has relatively low network traffic demands (e.g., the number of requested V2X transmissions is less than or equal to a threshold), the UE can use a larger number of RBs per V2X transmission. The UE can configure a smaller number of RBs per V2X transmission by using a higher MCS index, by disabling retransmissions or configuring a smaller number of retransmissions, by using a smaller TB size, and / or by using a smaller number of RBs per TB. Conversely, the UE can configure a larger number of RBs per V2X transmission by using a lower MCS index, by enabling retransmissions or configuring a larger number of retransmissions, by using a larger TB size, and / or by using a larger number of RBs per TB.

[0077] Additionally or alternatively, the UE may determine one or more transmission parameters at least in part based on the congestion level associated with the radio network over which the V2X transmission is to be sent (e.g., the congestion level of the sidelink channel and / or one or more frequencies over which the V2X transmission is to be sent). For example, if the radio network has a relatively high congestion level, the UE may use a smaller number of RBs per V2X transmission. Conversely, if the radio network has a relatively low congestion level, the UE may use a larger number of RBs per V2X transmission. In some aspects, the UE may determine the congestion level at least in part based on CBR, resource limitations (e.g., rate control parameters, power control parameters, congestion control parameters, etc.), measurement parameters of the radio network (e.g., energy level), etc.

[0078] The UE may send V2X transmissions (e.g., to a second UE and / or one or more other UEs) at least in part based on one or more parameters. For example, the UE may use a selected MCS to modulate and / or encode the V2X transmission, may use a selected number of TBs to send the V2X transmission, may use a selected number of RBs per TB to send the V2X transmission, may retransmit or prevent retransmission of the V2X transmission according to a selected retransmission configuration, may send the V2X transmission on a selected carrier frequency, etc. By considering dynamic factors when determining the above transmission parameters, the UE can improve the performance (e.g., transmission range) of V2X transmissions that comply with the constraints on V2X transmissions. For example, in some cases, the UE may use an MCS with a high index to send the V2X transmission instead of discarding the V2X transmission.

[0079] Figure 4 FIG. 400 is an example diagram showing device-to-device communication. A first device 412 (e.g., a UE) is present in a first vehicle 410 and can thus travel with the first vehicle 410. A second device 432 (e.g., another UE) may be present in a second vehicle 430. In another aspect, the first device 412 may exist independently of the first vehicle 410 or may be part of the first vehicle 410. The second device 432 may exist independently of the second vehicle 430 or may be part of the second vehicle 430. The first device 412 and the second device 432 may be connected (e.g., in a connection mode with a base station) to a base station 450. The first device 412 and the second device 432 may also be configured to perform D2D communication with each other via NR. The first device 412 and the second device 432 may also perform short-range communication with each other via IEEE 802.11p.

[0080] Vehicles may include autonomous vehicles, semi-autonomous vehicles, non-autonomous vehicles, etc. Although Figure 4Two UEs in [the context] are shown as being associated with a vehicle, but in some aspects, one or more of these UEs may not be associated with a vehicle. For example, a UE may be associated with infrastructure (e.g., transportation infrastructure), such as traffic signals, lane signals, sensors, traffic controller systems, etc.

[0081] NR V2V communication can provide more reliable performance compared to LTE V2V by providing a more history-based calculation of congestion and / or a more restricted reliance on future periodic transmissions. Although the following discussion relates to NR V2V communication by way of illustration and not limitation, NR V2V communication is similar to NR D2D communication, and thus the following discussion may also apply to NR and LTE D2D communication.

[0082] Congestion may occur in NR V2V communication, e.g., due to increased network traffic. Congestion control can be implemented to control network congestion based on the congestion level via certain parameters related to communication through NR V2V. For example, in some cases, there may be no centralized entity to perform congestion control of the spectrum. Congestion control can be performed without a centralized entity (e.g., eNB) to manage grant control and / or radio resource utilization (e.g., operation outside network coverage, and / or using a decentralized resource selection / reselection process). In the absence of a centralized entity to manage network resources and device communication, conflicts between different communications may occur. Excessive conflicts may have an adverse impact on the performance of the communication system. For example, conflicts may occur when resources are not properly allocated to different device communications (which may result in some devices not having sufficient resources for communication). Depending on the communication system and / or the channel access method of the communication system, a device may not be able to handle network congestion. For example, the number of communications that can be successfully and reliably performed in the network may vary depending on the type of communication system. Decentralized congestion control can be based on the 802.11p physical layer and can be generalized to provide coexistence of various technologies. Thus, in a system without a centralized entity for managing congestion, technology-neutral decentralized congestion control may be desirable. In some aspects, technology-specific enhancements for decentralized congestion control may be provided.

[0083] In one aspect, congestion control can be based on the channel busy rate (CBR) and / or channel utilization. The CBR can represent the percentage of busy resources. Channel utilization can represent the percentage of the channel being used for communication. The CBR and channel utilization can be technology-neutral, as described below. Decentralized congestion control for 802.11p technology can be derived from technology-neutral congestion control, and the technology-neutral method for decentralized congestion control can be used for NR V2V.

[0084] Each UE can estimate the channel utilization rate based on CBR. CBR can be an estimate of the percentage of resources considered busy / used. In one aspect, if a signal is decoded on a resource, or if the energy in such a resource is greater than an energy threshold, then such a resource can be considered busy and / or used.

[0085] The CBR can be estimated according to the following equation by dividing the number of probes that find busy resources by the total number of probes on the resource:

[0086]

[0087] where:

[0088] 1Vprobe with resource busy is an indicator function for probes that find a resource busy.

[0089] Np is the total number of probes for which resources are probed for resource busy measurement.

[0090] Nt is the time granularity of resource utilization (e.g., 1ms TTI for NR, OFDM symbol duration for 802.11p)

[0091] Nf is the frequency granularity of resource utilization (e.g., channel BW for 802.11p, 180kHz for NR). When resources are allocated in time and frequency, Nt and Nf can define the granularity of the resources.

[0092] For example, if a UE probes once every 10 microseconds, probing for 100 milliseconds will result in a total number of probes equal to 10000. If there are a total of 10000 probes for probing busy resources and 8000 probes find the probed resources to be busy, then the CBR of the system can be 80%.

[0093] CBR can be a function of the number of stations N Sta (e.g., number of UEs, number of transmitters):

[0094] CBR = f(N sta )

[0095] where the function f(N sta ) can be technology-dependent and can depend on the channel access procedure of the corresponding technology.

[0096] In one aspect, if the estimated CBR exceeds the CBR limit (CBR limit) Congestion control can be performed by limiting the channel utilization rate per UE. The channel utilization rate per UE can be expressed as the channel resource (CR). The CR limit (e.g., per UE or STA) can be determined by dividing the total resources available to the system (e.g., CBR lim ) by the number of stations (e.g., UEs) N Sta and can be expressed as:

[0097]

[0098] In an alternative formula, since congestion control can be activated when the estimated CBR exceeds the CBR limit (CBR limit ), the CR limit (e.g., per UE or STA) can be determined as:

[0099]

[0100] In one method, a linear function of N Sta can be used to estimate the CBR, which can be expressed as CBR = a*N sta +b. For coexistence with the technology of 802.11p, the parameters can be 1 / a = 4000 and b = 0.62 (the target CBR limit). Additionally, due to TDMA access (when the device transmits over the entire channel bandwidth and there is no FDMA operation), the CR for 802.11p can be estimated as T on / (T on +T off ), where T on is the duration when the UE is on, and T off is the duration when the UE is off. The CR limit can be estimated as T on / (T on +T off_limit ), where T off_limit is the minimum time for which the UE can be off to keep the channel utilization rate less than the CR limit.

[0101] Using the above method for 802.11p, the following equation can be achieved.

[0102]

[0103] Therefore, the CR for 802.11p can be T on divided by the total time: CR = T on / (T on +T off)。For example, if the UE is on for 400 milliseconds and off for 100 milliseconds, the CR is 400 / (400 + 100) = 4 / 5. In one aspect, if the UE is on for a longer time, the UE should be off for a longer time. Additionally, as shown above, T off or T off_limit can be a linear function of T on depending on the CBR. Thus, if the channel is busy and thus the CBR is high, the UE may back off more on transmissions due to a larger T off or a larger T off_limit .

[0104] The above congestion control method may have the following limitations when used in a system where multiple technologies share network resources. First, the CBR and channel utilization rate (e.g., CR) definitions may only apply to TDMA systems, where CR = T on / (T on + T off ). Second, a UE that estimates the CBR of the system may treat all radio resources equally, which may cause problems for NR V2V. Specifically, for NR V2V, the total radio resources can be divided into control resources and data resources. When separate resources are used for control and data, the control resources may become congested while the overall resources are not congested (e.g., because the data resources are idle rather than congested). In such an example, when there are different types of resources, treating all resources equally may not effectively solve the congestion of resources in the system. Therefore, a method of separately considering the CBR for control resources and the CBR for data resources is desired. For example, by separately considering the CBR for control resources and the CBR for data resources, if the control resources are too congested, the system may fail even if the data resources are available. Similarly, by separately considering the CBR for control resources and the CBR for data resources, if the data resources are too congested, the system may fail even if the control resources are available.

[0105] Third, as discussed above, if the energy for decoding a signal on a resource and / or measured on a resource is greater than a threshold, the UE can determine that the resource is busy. However, such a determination of busy resources by the UE may not consider the coexistence of multiple technologies on the same channel. Therefore, a congestion control method for the coexistence of multiple technologies when solving network congestion is desired. For example, according to one aspect of the present disclosure, to achieve coexistence, if the total channel utilization rate is 80%, each of these technologies may not be allowed to utilize more than 40% of the total resources.

[0106] Fourth, using a single threshold for CBR that is independent of the transmission priority may not allow the UE to make the transmission of higher-priority packets more important than the transmission of lower-priority packets. Therefore, it may be beneficial for the system to have different congestion limits for packets with different priorities. In one aspect, it may be desirable to control packet transmission based on the priority of the packet. For example, according to one aspect of the present disclosure, if the channel utilization exceeds a certain threshold (e.g., 50%), the UE may not send low-priority packets but may send high-priority packets, which can provide more resources for sending higher-priority packets.

[0107] According to a first aspect of the present disclosure, CBR may be defined based on the percentage of radio resources that are busy / being utilized within a measurement window. The UE may calculate a CBR (CBR e ) based on the energy measurement on the resource and a CBR (CBR d ) based on decoding the signal on the resource. Specifically, when calculating CBR e , if the energy measured on the resource is greater than a threshold (e.g., energy S > S threshold ), the UE may determine that the resource is busy. When calculating CBR d , if the signal on the resource is decoded, the UE may determine that the resource is busy. If the cyclic redundancy check (CRC) passes, the UE may determine that the signal on the resource is decoded. CBR e and CBR d may be expressed as follows:

[0108]

[0109] According to a second aspect of the present disclosure, for a system with separate control resources and data resources, the UE may calculate the CBR for the control resources and the CBR for the data resources separately. For example, the UE may calculate four types of CBR, which include an energy-based CBR for control resources (CBR control e ), a decoding-based CBR for control resources (CBR control d ), an energy-based CBR for data resources (CBR data_e ) and a decoding-based CBR for data resources (CBR data_d ), as follows:

[0110]

[0111] According to a third aspect of the present disclosure, an upper limit for CBR (e.g., CBR control_e , CBR control_d, CBR data_e , CBR data_d ). In one aspect, an upper limit for each type of CBR can be provided via pre - configuration and / or dynamic configuration (e.g., CBR limit ). In one aspect, pre - configuration can be performed via at least one of a UE or a Universal Integrated Circuit Card (UICC). In one aspect, dynamic configuration is performed based on at least one of RRC signaling from a base station, signaling from an Intelligent Transportation System (ITS) server, or signaling from an operator - controlled server. For example, the base station can provide the upper limit to the UE via an RRC message, or the upper limit can be pre - configured within the UE.

[0112] According to a fourth aspect of the present disclosure, the CR upper limit (CR limit ) for the channel utilization rate defined by CR (e.g., based on a percentage of radio resources) can be calculated as follows:

[0113]

[0114] where f -1 (CBR)=N Sta such that the inverse function f -1 can determine the number of stations (e.g., UE, transmitter) based on CBR.

[0115] The inverse function f -1 can be configured, e.g., via pre - configuration or dynamic configuration within the UE. In one aspect, pre - configuration can be performed via at least one of a UE or a UICC. In one aspect, dynamic configuration is performed based on at least one of RRC signaling from a base station, signaling from an ITS server, or signaling from an operator - controlled server. In one aspect, the function f can be a fixed function (e.g., linear or exponential), or can be dynamically configured in the UE. Based on the CBR limit, the UE can calculate CR limit in accordance with the percentage of radio resources that the UE is allowed to occupy, where CR limit can represent the maximum allowable channel utilization rate.

[0116] CR limit can be determined based on an energy - based CBR or a decoding - based CBR, depending on whether the UE detects another technology different from the UE's technology. Specifically, if the UE determines that it has detected another technology, the UE can determine CR limit according to the decoding - based CBR. If the UE determines that it has not detected another technology, the UE can determine CR limit according to the energy - based CBR. Thus, for example, the CR limit can be determined as follows:

[0117] If (e.g., 0.75)

[0118] then:

[0119] Otherwise:

[0120] In the above example, the UE can detect another technique by considering energy instances where the energy (Ec) on a resource is greater than a threshold (Th) and decoding instances where a signal (Ed) can be decoded for a resource having an energy (Ec) greater than the threshold (Th). If the ratio of decoding instances to energy instances drops below a technique threshold (Th2), the UE determines that there is another technique and can use the CBR for coexistence between multiple techniques limit_d to calculate the CR limit . If the ratio of decoding instances to energy instances does not drop below the technique threshold (Th2), the UE can determine that there is no other technique and thus use the CBR limit_e to calculate the CR limit . In one aspect, the UE can ensure that the CBR limit_d is less than or equal to the CBR limit_e . f -1 (CBR d ) can be the number of stations (e.g., UE, transmitter) using the same technique as the UE calculates the CR limit , because the UE may not be able to decode signals of different techniques. On the other hand, f -1 (CBR e ) can be the number of stations (e.g., UE, transmitter) using any technique, because the UE considers the energy on the resource, which can include the energy caused by the UE's technique and the energy caused by other techniques.

[0121] If no co-channel coexistence is expected between different techniques, the CBR limit_d may not be configured, and the CR limit may be given by the CBR limit_e .

[0122] According to a fifth aspect of the present disclosure, the UE can adjust transmission parameters (e.g., the number of occupied resources, MCS, transmission rate, number of HARQ retransmissions, transmission power, etc.) to keep the CR value below the CR limit . For example, if the CR limitIndicating 10% of the total resources and the current CR being greater than 10%, the UE can increase the MCS to improve the decoding rate, so that less resources can be used to send the same amount of data to reduce the CR to 10%. In another example, if the UE performs multiple transmissions, the UE can adjust the number of transmissions to adjust the CR, where reducing the number of transmissions can reduce the CR. In another example, the UE can reduce the CR by increasing the periodicity of the transmissions (e.g., to address congestion) and / or by reducing the number of HARQ retransmissions. The transmission rate is the rate at which the UE performs transmissions. For example, the UE can reduce the transmission rate to send once every 200 milliseconds instead of every 100 milliseconds to reduce congestion. In one aspect, the UE can perform the fifth aspect of the present disclosure after performing the fourth aspect of the present disclosure.

[0123] According to the sixth aspect of the present disclosure, the CBR limit can vary according to the packet priority of the packet. In one aspect, the UE can calculate the CR according to the priority of the packet being transmitted limit . In one aspect, a higher CR limit can be used for higher priority packets. For example, if the system supports packets with three priorities (p = 0, 1, 2) (where p = 0 is the highest priority), the UE can determine different CBRs limit values for each of the different priorities. Specifically, the UE can determine the CBR for p = 0 limit_p0 , the CBR for p = 1 limit_p1 , and the CBR for p = 2 limit_p2 , where the CBR limit_p2 < CBR limit_p1 < CBR limit_p0 (e.g., CBR limit_p2 = 0%, CBR limit_p1 = 50%, CBR limit_p0 = 80%). In this example, if the CBR increases above 30%, the UE can avoid sending packets with priority 2 (p = 2). In one aspect, for example, the sixth aspect of the present disclosure can ensure that lower priority traffic can congest the system up to a low threshold (e.g., 30%), while allowing higher priority traffic to congest the resources up to a high threshold (e.g., 80%) and still allowing the successful transmission of higher priority traffic.

[0124] According to the seventh aspect of the present disclosure, if the UE is sending packets with different priorities, the priority information of the packets can be considered as follows. When the UE has packets with different priorities for transmission, the UE can determine the CBR per priority limit and the CR per prioritylimit Therefore, CBR limit and CR limit vary based on priority. If the CBR is lower than the CBR for a specific priority limit , the UE may send packets with a specific priority. For example, if the CBR is lower than the CBR limit_p1 , the UE may send packets with priority p1. However, if the CBR is greater than the CBR for low priority limit and less than the CBR for high priority limit , the UE may send packets with high priority and may not send packets with low priority. For example, in the case of CBR limit_p2 < CBR limit_p1 < CBR limit_p0 , if the CBR is lower than the CBR limit_p2 , the UE may send packets with priority p2 as well as packets with priority p1 and packets with priority p0. On the other hand, if the CBR is greater than the CBR limit_p1 and less than the CBR limit_p0 , the UE may send packets with priority p0, but may not send packets with priority p1 or priority p2.

[0125] If packets with different priorities can be sent, the UE may send packets according to at least one of the following options. According to the first option, the UE may first send all higher priority packets before sending lower priority packets. In one aspect, before transmission, packets may be placed in different transmission queues based on different priorities. Thus, the UE may empty the higher priority packet queue to prepare the higher priority packets for transmission before accessing the lower priority packet queue.

[0126] According to the second option, the UE may assign different weights to different priorities and may send packets with different priorities based on the weights. The per-priority weight w_p may define a fraction of the packets with priority p to be sent. For example, if the packets have two priorities p1 and p2 with weights w_1 = 0.75 and w_2 = 0.25 respectively, three p1 packets may be sent for every p2 packet. Based on the per-priority CBR limit, if the set of priorities that the UE can send is P = {0, 1,..., p - 1}, the weights for the priorities may be normalized such that the sum of the normalized weights is equal to 1 within the set P, based on: where, Is the normalized weight for the priority. In an example where four priorities in a group are possible and w_0 = 0.6, w_1 = 0.2, w_2 = 0.15, w_3 = 0.05, when packets with priority p0 and priority p1 can be sent (e.g., P = {0,1}), w_0 and w_1 can be normalized such that the sum of the normalized weights equals 1. Thus, in this example, the normalized w_0 = 0.75 and the normalized w_1 = 0.25, such that the sum of the normalized w_0 and the normalized w_1 is 1.

[0127] The systems and methods described herein relate to enhanced congestion control enhancements for D2D communication (including for non-periodic communication). The enhanced functionality can achieve enhanced or improved operation in the NR V2X mode. In some implementations, the systems and methods described herein implement congestion control based on a CR window that is more time-constrained compared to LTE. For example, the CR window can limit future usage estimates to currently scheduled or granted non-periodic transmissions. Thus, such systems and methods can better support non-periodic transmissions and can be used in the URLLC mode.

[0128] Figure 5 An example of a wireless communication system 500 that supports D2D congestion control in accordance with aspects of the present disclosure is shown. In some examples, the wireless communication system 500 can implement aspects of the wireless communication system 100. For example, the wireless communication system 500 can include a UE 115, a network entity 515 (e.g., a second UE), and optionally a second network entity 505 (e.g., a base station 105). The enhanced congestion control operation can enable the transmission of more non-periodic communication and thus can increase throughput and reduce latency. Such increased throughput and reduced latency can enable URLLC and can be used to improve reliability and throughput when there may be congestion between devices.

[0129] The network entity 515 and the UE 115 can be configured to communicate via a frequency band (such as for millimeter wave, having a frequency FR1 of 410 to 7125 MHz or a frequency FR2 of 24250 to 52600 MHz). Note that for some data channels, the subcarrier spacing (SCS) can be equal to 15, 30, 60, or 120 kHz. The network entity 515 and the UE 115 can be configured to communicate via one or more component carriers (CCs) (such as a representative first CC 581, a second CC 582, a third CC 583, and a fourth CC 584). Although four CCs are shown, this is for illustration only, and more or fewer than four CCs can be used. One or more CCs can be used to transmit control channel transmissions, data channel transmissions, and / or sidelink channel transmissions.

[0130] For example, sidelink channel transmissions 556 can be sent between UE 115 and network entity 515. Optionally, data and control channel transmissions 552 and 554 can be sent between UE 115 and second network entity 505. Such transmissions can include Physical Downlink Control Channel (PDCCH), Physical Downlink Shared Channel (PDSCH), Physical Uplink Control Channel (PUCCH), Physical Uplink Shared Channel (PUSCH), PSCCH, PSSCH, or PSFCH. Such transmissions can be scheduled via an aperiodic grant and / or a periodic grant.

[0131] Each periodic grant can have a corresponding configuration, such as configuration parameters / settings. The periodic grant configuration can include Configured Grant (CG) configuration and settings. Additionally or alternatively, one or more periodic grants (e.g., their CGs) can have or be assigned a CC ID, such as an expected CC ID.

[0132] Each CC can have a corresponding configuration, such as configuration parameters / settings. The configuration can include bandwidth, bandwidth part, HARQ process, TCI state, RS, control channel resources, data channel resources, or a combination thereof. Additionally or alternatively, one or more CCs can have or be assigned a cell ID, a Bandwidth Part (BWP) ID, or both. The cell ID can include a unique cell ID for the CC, a virtual cell ID, or a specific cell ID for a particular CC among multiple CCs. Additionally or alternatively, one or more CCs can have or be assigned a HARQ ID. Each CC can also have a corresponding management function, such as beam management, BWP switching function, or both. In some implementations, two or more CCs are quasi-co-located such that the CCs have the same beam and / or the same symbol.

[0133] In some implementations, control information can be conveyed via network entity 515 and UE 115. For example, MAC-CE transmissions, RRC transmissions, DCI transmissions, another transmission, or a combination thereof can be used to convey control information.

[0134] UE 115 includes a processor 502, a memory 504, a transmitter 510, a receiver 512, an encoder 513, a decoder 514, a CR window determiner 516, a CR value determiner 517, and antennas 252a-r. The processor 502 may be configured to execute instructions stored at the memory 504 to perform the operations described herein. In some implementations, the processor 502 includes or corresponds to the controller / processor 280, and the memory 504 includes or corresponds to the memory 282. The memory 504 may also be configured to store CBR data 506, CR data 508, usage data 542, a threshold 544, or a combination thereof, as further described herein.

[0135] The CBR data 506 includes or corresponds to data for the channel busy rate for one or more resources, such as a resource pool. The resource pool may include sidelink channels, such as one or more of PSCCH, PSSCH, or PSFCH. The CBR data 506 may include data indicating a CBR window (such as which subframes are in a given CBR window), indicating a CBR measurement value, or both. In some implementations, the CBR measurement value is an emergency-based CBR value, such as a CBR value determined based on energy (e.g., RSSI). For example, if the RSSI is higher than a threshold, the resource is determined to be busy or in use. The CBR may correspond to the ratio of busy resources to total resources.

[0136] The CR data 508 includes or corresponds to data for the channel occupancy rate for one or more resources. The CR data 508 may include data indicating a CR window (such as which subframes are in a given CR window), indicating a CR measurement value, or both. The CR window may be determined based on the usage data 542. The usage data 542 indicates usage history and estimated future usage. In a particular implementation, the CR window is determined based on estimated future usage limited to current non-periodic transmissions and their retransmissions. The CR measurement value may be determined based on the CBR measurement value. For example, the CR measurement value may be determined based on the CBR value and one or more thresholds indicated by the threshold 554, and adjusted or evaluated.

[0137] In addition, the CBR data 506 and the CR data 508 may include setting data, such as window size or duration settings, window parameters, measurement parameters, etc. Such settings may be pre-set and / or RRC configurable. In addition, other related settings may be stored in the memory 504, such as the allowed number of retransmissions and / or the timing of retransmissions.

[0138] The transmitter 510 is configured to send data to one or more other devices, and the receiver 512 is configured to receive data from one or more other devices. For example, the transmitter 510 may send data via a network (such as a wired network, a wireless network, or a combination thereof), and the receiver 512 may receive data via the network. For example, the UE 115 may be configured to send and / or receive data via: a direct device-to-device connection, a local area network (LAN), a wide area network (WAN), a modem-to-modem connection, the Internet, an intranet, an extranet, a cable transmission system, a cellular communication network, any combination of the foregoing, or any other communication network known now or developed later that allows two or more electronic devices to communicate therein. In some implementations, the transmitter 510 and the receiver 512 may be replaced by a transceiver. Additionally or alternatively, the transmitter 510, the receiver 512, or both may include or correspond to one or more components of the UE 115 described with reference to Figure 2 one or more components of the UE 115 described with reference to

[0139] The encoder 513 and the decoder 514 may be configured to encode and decode data for transmission. The CR window determiner 516 may be configured to determine the window size and / or position of the CR window. For example, the CR window determiner 516 is configured to determine the size and position of the subframes for the CR window. The CR value determiner 517 may be configured to determine and / or evaluate the CR value of one or more subframes for the CR window. For example, the CR value determiner 517 is configured to determine the CR value of the subframes for the window and compare it with the corresponding CBR value to determine whether the CR value and / or one or more transmission parameters should be adjusted.

[0140] The network entity 515 includes a processor 530, a memory 532, a transmitter 534, a receiver 536, an encoder 535, a decoder 538, and antennas 234a-t. The processor 530 may be configured to execute instructions stored at the memory 532 to perform the operations described herein. In some implementations, the processor 530 includes or corresponds to the controller / processor 240, and the memory 532 includes or corresponds to the memory 242. The memory 532 may be configured to store CBR data 506, CR data 508, usage data 542, thresholds 544, or a combination thereof, similar to the UE 115 and as further described herein.

[0141] The transmitter 534 is configured to send data to one or more other devices, and the receiver 536 is configured to receive data from one or more other devices. For example, the transmitter 534 may send data via a network (such as a wired network, a wireless network, or a combination thereof), and the receiver 536 may receive data via the network. For example, the network entity 515 may be configured to send and / or receive data via: direct device-to-device connections, local area networks (LANs), wide area networks (WANs), modem-to-modem connections, the Internet, intranets, extranets, cable transmission systems, cellular communication networks, any combination of the foregoing, or any other communication network known now or developed later that permits two or more electronic devices to communicate therein. In some implementations, the transmitter 534 and the receiver 536 may be replaced by a transceiver. Additionally or alternatively, the transmitter 534, the receiver 536, or both may include or correspond to one or more components of the network entity 515 described with reference to Figure 2 one or more components of the network entity 515 described. The encoder 535 and the decoder 538 may include the same functionality described with reference to the encoder 513 and the decoder 514, respectively.

[0142] During operation of the wireless communication system 500, the network entity 515 and / or the second network entity 505 may determine that the UE 115 has enhanced congestion control capabilities. For example, the UE 115 may send a message 548 that includes an enhanced congestion control indicator 592. The indicator 592 may indicate enhanced congestion control capabilities or a particular type of enhanced congestion control, such as enhanced congestion control for NR V2X. In some implementations, the second network entity 505 sends control information to indicate to the UE 115 to use enhanced congestion control. For example, in some implementations, the message 548 (or another message, such as a configuration transmission 550) is sent by the second network entity 505. The configuration transmission 550 may include or indicate the use of enhanced congestion control, or adjust or implement settings for enhanced congestion control, such as window size or threshold.

[0143] During operation, a device of the wireless communication system 500 transmits control, data, and / or sidelink channel transmissions to other devices of the wireless communication system 500. For example, the UE 115 and a base station (e.g., 505) can transmit control and data information on control and data channels. Multiple terminal devices or UEs can directly transmit control and data information to each other on one or more sidelink channels and independently of the base station of the wireless communication system 500. One or more of the terminal devices or UEs can perform congestion control operations. For example, the UE 115 can track the usage of one or more sidelink channel resources (such as PSCCH and PSSCH or PSCCH, PSSCH, and PSFCH). In addition, the UE 115 can estimate the usage of one or more sidelink channel resources for future transmissions. Future transmissions can include future retransmissions of current transmissions and (optionally) future transmissions and any retransmissions. In a particular implementation, future transmissions are limited to the last transmission of the current transmission or an active transmission (such as a currently scheduled transmission). In such an implementation, the UE 115 can disregard or avoid considering future periodic transmissions.

[0144] Additionally, when using a set or configurable window size, limiting future transmissions can place more emphasis on previous transmissions, and / or can extend the history to include a longer transmission history.

[0145] Based on the tracked usage history and the estimated usage, the UE 115 can determine a CBR measurement value. The CBR measurement value can be associated with a specific CBR window. The size of the CBR window can be pre-set or configured by a device of the wireless communication system 500.

[0146] Furthermore, the UE 115 determines a CR window and a CR value. The CR can be evaluated at a specific subframe (such as subframe n). The CR value can be determined based on the total number of subchannels used for previous transmissions and the subchannels granted for future subframes divided by the total number of configured subchannels within the considered window. For example, the window can be defined by how many transmissions and what type (previous or future) of transmissions are to be considered for CR calculation.

[0147] For example, the CR window determiner 516 determines a window for a specific subframe based on the window size, such as the positions of the start subframe and the end subframe. For example, the CR window determiner 516 determines the position of the window based on an equation. As an illustrative non-limiting example, the window position is determined based on the equation a + b + 1 = C, where a is a positive integer, b is 0 or a positive integer, and C is the size or duration of the CR window. In some implementations, C can be a number, such as 1000 ms. In other implementations, C can be determined based on a formula, such as X multiplied by the size or duration of the CBR window. For example, C can be equal to 10 times the size of the CBR window. In a specific implementation, n + b should not exceed the last scheduled retransmission for the current transmission. Thus, for the window of [n - a, n + b], the CR window start position and end position can be frame n - a and frame n + b. Thus, the CR can be determined based on the total number of subchannels used for its transmission in subframe [n - a, n - 1] and permitted in subframe [n, n + b] divided by the total number of subchannels configured in the transmission pool in [n - a, n + b].

[0148] The CR value determiner 517 determines a CR value for a specific subframe (n) and window based on subchannel usage (such as described above) and based on the CBR value. For example, the CR value determiner 517 can determine the CR value based on subchannel usage as described above. The determined CR value can be adjusted based on the corresponding CBR value. For example, the determined CR value can be compared with one or more specific CBR thresholds (which are determined based on the CBR value). In a specific implementation, the CR value is adjusted based on this comparison, such as by a table or a formula. The corresponding CBR value can include or correspond to the CBR value for a window similar to the CR value or for the same subframe.

[0149] The UE 115 can perform congestion control based on the CR value. For example, the UE 115 can adjust its subchannel usage based on the CR value. For example, the UE 115 can adjust its subchannel usage for the PSCCH and PSSCH with the network entity 515 or for the PSCCH, PSSCH, and PSFCH with the network entity 515. As another example, the UE 115 can adjust the transmission settings based on the CR value.

[0150] Therefore, Figure 5 Enhanced congestion control operations for D2D communication are described. When operating in D2D mode, improvements can be achieved using enhanced congestion control. Performing enhanced congestion control operations enables the network to reduce latency and improve reliability. Improving performance can increase the throughput for communication on the network and enable the use of millimeter wave frequency ranges and URLLC modes.

[0151] Figure 6 is a block diagram showing example blocks performed by a UE configured according to an aspect of the present disclosure. Example blocks will also be described with respect to the UE 115 as shown Figure 8 in the UE 115. Figure 8 is a block diagram showing the UE 115 configured according to an aspect of the present disclosure. The UE 115 includes the structures, hardware, and components shown for the UE 115 as Figure 2 shown. For example, the UE 115 includes a controller / processor 280 that operates to execute logic units or computer instructions stored in a memory 282 and controls the components that provide the features and functions of the UE 115. Under the control of the controller / processor 280, the UE 115 transmits and receives signals via wireless radio units 800a-r and antennas 252a-r. The wireless radio units 800a-r include the respective components and hardware shown for the UE 115 in Figure 2 , which include modulators / demodulators 254a-r, MIMO detectors 256, receive processors 258, transmit processors 264, and TX MIMO processors 266. As shown in the example of Figure 8 , the memory 282 stores D2D logic 802 (e.g., NR V2X logic), CBR logic 803, CR logic 804, feedback channel logic 805, usage data 806, and setting data 807.

[0152] At block 600, a mobile communication device (such as a UE) determines a CBR window for channel busy rate (CBR) measurements for one or more resources. The UE (such as the UE 115) receives and transmits transmissions via wireless radio units 800a-r and antennas 252a-r and records the usage of the transmissions and any future / scheduled transmissions. The one or more resources may include or correspond to a pool of resources, such as a resource pool. The one or more resources may include sidelink channel resources, such as PSCCH, PSSCH, PSFCH, etc.

[0153] Under the control of the controller / processor 280, the UE 115 may execute the D2D logic 802 stored in the memory 282. The execution environment of the D2D logic 802 provides the UE 115 with the function of defining and executing congestion control procedures. In addition, the UE 115 may execute one or more of the CBR logic 803 and / or CR logic 804. The execution environment of the D2D logic 802 (and optionally the CBR logic 803 and / or CR logic 804) defines different congestion control procedures, such as determining the CBR window, CBR value, CR window, CR value, or a combination thereof. For example, the UE 115 may determine the CBR window based on the set size or duration of the sidelink channel resource.

[0154] At block 601, the UE 115 determines CBR measurements for the CBR window and for one or more resources. The CBR measurements can be energy-based CBR values, such as based on RSSI. For example, it can be determined that a resource is occupied or busy based on the energy value exceeding a threshold energy value. Under execution logic such as in D2D logic 802 and / or CBR logic 803, the UE 115 determines the CBR value for the sidelink channel resource and based on the sidelink channel resource.

[0155] At block 602, the UE 115 determines a channel occupancy rate (CR) window based on a first number of subframes used for historical transmissions in the past and based on a second number of subframes used for future scheduled transmissions and corresponding retransmissions. For example, the UE 115 determines the amount of subframes used for historical use and the amount of subframes for future transmissions. By way of example, the UE 115 can determine to use a number X of subframes for future transmissions, where X corresponds to the subframe of the last retransmission of the current transmission. Then, the UE 115 can determine to use a number Y of subframes based on the number X and the size of the CR window.

[0156] At block 603, the UE 115 determines a CR value for the CR window based on the subchannels used for one or more resources for a first number of subframes and based on the subchannels estimated for one or more resources for a second number of subframes. Additionally, the UE 115 can determine the CR value based on the CBR value. For example, the UE 115 determines the CR value based on the used subchannels and the available subchannels, and the UE 115 can adjust the CR value based on the CBR value. The UE 115 can perform congestion control operations as described herein based on the CR value and optionally the CBR. For example, the UE can adjust the channel usage based on a CBR threshold, which is determined based on the CBR value. By way of example, one or more CBR thresholds with corresponding CR limits are set. Whenever the measured CBR reaches the threshold or meets the condition, the UE checks whether its CR value is within the corresponding CR limit. If not, the CR value is adjusted, and congestion control can be performed.

[0157] In other implementations, the UE 115 can perform additional blocks (or the UE 115 can be configured to further perform additional operations). For example, the UE 115 can perform one or more of the above operations. As another example, the UE 115 can perform one or more aspects as described below.

[0158] In a first aspect, the last transmission in the future scheduled transmissions is the last retransmission of the currently scheduled transmission.

[0159] In a second aspect, either alone or in combination with the first aspect, determining the CR window includes avoiding considering future periodic transmissions scheduled by previously received periodic grants.

[0160] In a third aspect, either alone or in combination with one or more of the above aspects, the CR value corresponds to a specific subframe of the CR window, and wherein determining the CR value includes: a first number of subchannels used by the UE based on a first number of subframes used for past transmissions of the CR window, a second number of subchannels for determining the CR value based on a second number of subframes used for future scheduled transmissions and corresponding retransmissions of the CR window, and evaluating a specific subframe of the CR window based on the total number of configured subchannels available for one or more resources in the CR window.

[0161] In a fourth aspect, either alone or in combination with one or more of the above aspects, future scheduled transmissions and corresponding retransmissions include retransmissions of currently scheduled transmissions, wherein the retransmissions occur within the packet delay budget from generation for each packet.

[0162] In a fifth aspect, either alone or in combination with one or more of the above aspects, the maximum number of retransmissions is based on HARQ feedback parameters.

[0163] In a sixth aspect, either alone or in combination with one or more of the above aspects, the CR window is further determined based on the duration of the CBR measurement window.

[0164] In a seventh aspect, either alone or in combination with one or more of the above aspects, the duration of the CR window is ten times the duration of the CBR measurement window.

[0165] In an eighth aspect, either alone or in combination with one or more of the above aspects, the duration of the CR window is 1000 milliseconds.

[0166] In a ninth aspect, either alone or in combination with one or more of the above aspects, UE 115 sets the duration of the CBR window, the duration of the CR window, or both based on an RRC message.

[0167] In a tenth aspect, either alone or in combination with one or more of the above aspects, the first number of subframes for the history of past transmissions is greater than or equal to half of the duration of the CR window.

[0168] In an eleventh aspect, either alone or in combination with one or more of the above aspects, the first number of subframes for the history of past transmissions is greater than or equal to 90% of the duration of the CR window.

[0169] In a twelfth aspect, either alone or in combination with one or more of the above aspects, determining the CR window includes determining the CR window based on the following formula: the sum of the total number of used sub-channels for sub-frames [n-a, n-1] and the total number of permitted sub-channels for sub-frames [n, n+b] divided by the total number of configured sub-channels for sub-frames [n-a, n+b], where a + b + 1 = C, where "a" corresponds to the first number of sub-frames for the history of past transmissions to be considered for the CR window, where "b" corresponds to the second number of sub-frames for future scheduled transmissions and corresponding retransmissions to be considered for the CR window, and where "C" is the duration of the CR window.

[0170] In a thirteenth aspect, either alone or in combination with one or more of the above aspects, the first number of sub-frames for the history of past transmissions to be considered for the CR window is greater than or equal to half of the duration of the CR window.

[0171] In a fourteenth aspect, either alone or in combination with one or more of the above aspects, the sum of the current frame and the second number of sub-frames is less than or equal to the sub-frame number corresponding to the last retransmission of the current transmission.

[0172] In a fifteenth aspect, either alone or in combination with one or more of the above aspects, determining the CBR measurement includes: determining a received signal strength indicator (RSSI) value; comparing the RSSI value with a threshold; determining that a resource is busy based on the RSSI value exceeding the threshold; and determining the CBR measurement based on the number of busy resources divided by the total number of resources in the CBR window.

[0173] In a sixteenth aspect, either alone or in combination with one or more of the above aspects, UE 115 determines the CBR measurement independently of the PSFCH resource.

[0174] In a seventeenth aspect, either alone or in combination with one or more of the above aspects, UE 115 determines a second CBR measurement for the PSFCH resource based on a second CBR window for the PSFCH resource.

[0175] In an eighteenth aspect, either alone or in combination with one or more of the above aspects, UE 115 determines the second CBR window for the PSFCH resource based on an RRC configurable parameter or a pre-configured second CBR window duration.

[0176] In a nineteenth aspect, alone or in combination with one or more of the above aspects, determining a second CBR measurement value for a PSFCH resource includes: determining a received signal strength indicator (RSSI) value for the PSFCH resource; comparing the RSSI value with a threshold; determining that a resource in the PSFCH resource is busy based on the RSSI value exceeding the threshold; and determining the second CBR measurement value based on the number of busy resources divided by the total number of resources in the CBR window.

[0177] In a twentieth aspect, alone or in combination with one or more of the above aspects, the UE 115 further determines a CBR measurement value based on the PSFCH resource.

[0178] In a twenty - first aspect (alone or in combination with one or more of the above aspects), the CBR measurement value is for the PSCCH, PSSCH, or both.

[0179] In a twenty - second aspect (alone or in combination with one or more of the above aspects), the CBR measurement value is for the PSCCH, PSSCH, and PSFCH.

[0180] In a twenty - third aspect, alone or in combination with one or more of the above aspects, determining a CR value for a CR window based on the CBR measurement value includes: selecting a CR value from a table based on the CBR measurement value; or calculating a CR value based on the CBR measurement value and a CR calculation formula.

[0181] In a twenty - fourth aspect, alone or in combination with one or more of the above aspects, the UE operates in a PSCCH / PSSCH multiplexing mode, and a single CBR measurement is performed for both the PSCCH and PSSCH.

[0182] In a twenty - fifth aspect, alone or in combination with one or more of the above aspects, the UE 115 performs congestion control based on the CR value, where performing congestion control includes one or more of the following: adjusting the amount of sub - channels for one or more resources, adjusting the amount of re - transmission, adjusting the modulation and coding scheme (MCS), or adjusting the communication channel frequency.

[0183] In a twenty - sixth aspect, alone or in combination with one or more of the above aspects, the UE is an autonomous vehicle configured for fifth - generation wireless new radio (5G NR) vehicle - to - everything (V2X) communication.

[0184] Therefore, the UE and the base station can perform enhanced congestion control for the D2D mode. By performing enhanced congestion control for the D2D mode, latency and overhead can be reduced, and throughput and reliability can be improved.

[0185] Figure 7 is a block diagram illustrating example blocks performed by a UE configured according to one aspect of the present disclosure. Example blocks will also be described with respect to the UE 115 as shown Figure 8 In block 700, a mobile communication device such as a UE determines a CBR window for channel busy rate (CBR) measurements for one or more resources. For example, the UE 115 determines a CBR window, similar to block 600.

[0186] In block 701, the UE 115 determines CBR measurement values for the CBR window and for one or more resources. The UE115 determines CBR values, similar to block 601.

[0187] In block 702, the UE 115 determines a channel occupancy rate (CR) window based on the CBR measurement values. For example, the UE 115 determines the size of the CR window based on the size of the CBR window. The size of the window may include or correspond to the duration of the window.

[0188] In other implementations, the UE 115 may perform additional blocks (or the UE 115 may be configured to further perform additional operations). For example, the UE 115 may perform one or more of the operations described above. As another example, the UE 115 may perform one or more aspects as described with reference to Figure 6 described.

[0189] Accordingly, the UE and the base station may perform enhanced congestion control for the D2D mode. By performing enhanced congestion control for the D2D mode, additional functions may be achieved, such as congestion control may be performed with a dynamic or flexible window size (e.g., duration). Accordingly, latency and overhead may be reduced, and throughput and reliability may be improved.

[0190] Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different technologies and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0191] Figure 6 and Figure 7 The functional blocks and modules in may include: a processor, an electronic device, a hardware device, an electronic component, a logic circuit, a memory, software code, firmware code, etc., or any combination thereof.

[0192] Those skilled in the art will also appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein can be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the disclosure. Those skilled in the art will also readily recognize that the order or combination of the components, methods, or interactions described herein are merely examples, and the components, methods, or interactions of the various aspects of the disclosure may be combined or performed in ways different from those shown and described herein.

[0193] The various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein can be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. 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 in conjunction with a DSP core, or any other such configuration.

[0194] The steps of a method or algorithm described in connection with the disclosure herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of both. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may exist as discrete components in a user terminal.

[0195] In one or more exemplary designs, the functions described can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions can be stored on or transmitted via a computer-readable medium as one or more instructions or code. Computer-readable media includes both computer storage media and communication media, where the communication media includes any medium that facilitates transfer of a computer program from one place to another. A computer-readable storage medium can be any available medium that can be accessed by a general-purpose or special-purpose computer. By way of example and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer or a general-purpose or special-purpose processor. Additionally, a connection can be properly termed a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, or digital subscriber line (DSL), then the coaxial cable, fiber optic cable, twisted pair, or DSL is included in the definition of the medium. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks typically reproduce data magnetically, while discs typically reproduce data optically using lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0196] As used herein (including in the claims), the term "and / or" when used in a list of two or more items means that any one of the listed items can be taken alone, or any combination of two or more of the listed items can be taken. For example, if a composition is described as including components A, B, and / or C, the composition can include: only A; only B; only C; a combination of A and B; a combination of A and C; a combination of B and C; or a combination of A, B, and C. Additionally, as used herein (including in the claims), the "or" as used in a list of items that ends with "at least one of" indicates a disjunctive list, such that for example, a list of "at least one of A, B, or C" means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) or any combination thereof.

[0197] The foregoing description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication, comprising: obtaining, by a user equipment (UE), sidelink channel congestion control information; determining, by the UE, a CR value for a channel occupancy rate (CR) window based on sub-channels used for one or more sidelink resources for a first number of sub-frames used in the history of past transmissions, and based on sub-channels estimated for one or more sidelink resources for a second number of sub-frames used in future planned transmissions and corresponding retransmissions; and performing, by the UE, a congestion control operation based on the CR value and the sidelink channel congestion control information.

2. The method according to claim 1, wherein, Obtaining the sidelink channel congestion control information includes: receiving, by the UE, a radio resource control (RRC) transmission including the sidelink channel congestion control information.

3. The method according to claim 1, wherein The sidelink channel congestion control information includes or corresponds to CR limit information.

4. The method according to claim 3, wherein, The CR limit information includes one or more CR thresholds for sidelink channel operation.

5. The method according to claim 1, wherein Performing the congestion control operation based on the CR value and the sidelink channel congestion control information includes: determining a specific CR limit from the sidelink channel congestion control information based on CBR information; and comparing the CR value with the specific CR limit.

6. The method according to claim 1, wherein The duration of the CR window does not exceed the sub-frame of the last planned retransmission of the future planned transmissions and corresponding retransmissions.

7. The method according to claim 1, wherein, The last transmission in the future planned transmissions and corresponding retransmissions is the last retransmission of the currently scheduled transmission.

8. The method according to claim 1, wherein Determining the CR window includes: avoiding including future periodic transmissions scheduled by a previously received periodic grant in the second number of sub-frames.

9. The method according to claim 1, wherein The CR value corresponds to a specific sub-frame of the CR window, and wherein determining the CR value includes: evaluating the specific sub-frame of the CR window based on a first number of sub-channels used for the first number of sub-frames used in the history of the past transmissions for the CR window, based on a second number of sub-channels used for determining the CR value for the second number of sub-frames used in the future planned transmissions and corresponding retransmissions for the CR window, and based on the total number of configured sub-channels available for the one or more sidelink resources in the CR window.

10. The method according to claim 1, wherein The future planned transmissions and corresponding retransmissions include retransmissions of the currently scheduled transmission, wherein the retransmissions occur within a packet delay budget starting from the generation of the currently scheduled transmission for each packet.

11. The method according to claim 1, wherein, The maximum number of the retransmissions is based on HARQ feedback parameters.

12. The method according to claim 1, further comprising: determining, by the UE, a CBR window for channel busy rate (CBR) measurement for the one or more resources; determining, by the UE, a CBR measurement value for the CBR window and for the one or more resources; and determining, by the UE, the CR window based on the first number of sub-frames used in the history of past transmissions, and based on the second number of sub-frames used in the future planned transmissions and corresponding retransmissions.

13. The method according to claim 12, wherein, The CR window is further determined based on the duration of the CBR window.

14. The method according to claim 1, wherein Performing the congestion control operation based on the CR value includes: Performing one or more operations including: adjusting the amount of subchannels for the one or more resources, adjusting the amount of retransmissions, adjusting the modulation and coding scheme (MCS), adjusting the communication channel frequency, avoiding sending communications during the CBR window associated with the CR window, or a combination thereof.

15. The method according to claim 1, wherein The future scheduled transmissions and corresponding retransmissions include current scheduled transmissions and corresponding retransmissions of the current scheduled transmissions, and further include: Receiving a scheduling message for the future scheduled transmissions and corresponding retransmissions before determining the CR window and the CR value; and Determining the future scheduled transmissions and corresponding retransmissions based on the scheduling message before determining the CR window and the CR value.

16. The method according to claim 1, wherein, The first number of subframes of the history for past transmissions is greater than half of the duration of the CR window, and wherein the sum of the subframe number for the current subframe and the second number of subframes is less than or equal to the subframe number corresponding to the last scheduled retransmission.

17. An apparatus configured for wireless communication at a user equipment (UE), the apparatus comprising: One or more processors; And A memory coupled to the one or more processors, wherein instructions are stored in the memory and executable by the one or more processors to cause the apparatus to perform the following operations: Obtain sidelink channel congestion control information; Determine a CR value for a channel occupancy rate (CR) window based on subchannels used for one or more sidelink resources for a first number of subframes used for the history of past transmissions and based on subchannels estimated for one or more sidelink resources for a second number of subframes used for future scheduled transmissions and corresponding retransmissions; And Perform a congestion control operation based on the CR value and the sidelink channel congestion control information.

18. The apparatus according to claim 17, wherein, The instructions are further executable by the one or more processors to cause the apparatus to perform the following operations: Receive a radio resource control (RRC) transmission including the sidelink channel congestion control information.

19. The device according to claim 17, wherein The sidelink channel congestion control information includes or corresponds to CR limit information.

20. The apparatus according to claim 19, wherein, The CR limit information includes one or more CR thresholds for sidelink channel operation.

21. The apparatus according to claim 17, wherein, The instructions for performing the congestion control operation further include instructions executable by the one or more processors to cause the apparatus to perform the following operations: Determine a specific CR limit from the sidelink channel congestion control information based on CBR information; and Compare the CR value with the specific CR limit.

22. The device according to claim 17, wherein The duration of the CR window does not exceed the subframe of the last scheduled retransmission of the future scheduled transmissions and corresponding retransmissions.

23. The device according to claim 17, wherein, The duration of the CR window is 1000 milliseconds, and wherein the future scheduled transmissions and corresponding retransmissions include non-periodic transmissions, periodic transmissions, or both.

24. The apparatus according to claim 17, wherein The instructions may also be executed by the one or more processors to cause the device to: set the duration of the CBR window, the duration of the CR window, or both, based on the sidelink channel congestion control information.

25. The apparatus according to claim 17, wherein, The first number of subframes for the history of past transmissions is greater than or equal to half of the duration of the CR window, and wherein the future scheduled transmissions and corresponding retransmissions represent actual scheduled transmissions or retransmissions that occur after determining the CR window and the CR value.

26. The apparatus according to claim 17, wherein, The instructions for determining the CR window further include instructions that may be executed by the one or more processors to cause the device to: determine the CR window based on the following formula: the sum of the total number of used subchannels for subframes [n - a, n - 1] divided by the total number of configured subchannels for subframes [n, n + b], where a + b + 1 = C, where "a" corresponds to the first number of subframes for the history of past transmissions to be considered for the CR window, where "b" corresponds to the second number of subframes for the future scheduled transmissions and corresponding retransmissions to be considered for the CR window, and where "C" is the duration of the CR window.

27. The apparatus according to claim 26, wherein, The first number of subframes for the history of past transmissions to be considered for the CR window is greater than or equal to half of the duration of the CR window, and wherein the sum of the current frame and the second number of subframes is less than or equal to the subframe number corresponding to the last retransmission of the current transmission.

28. The device according to claim 17, wherein, The instructions for performing the congestion control operation based on the CR value further include instructions that may be executed by the one or more processors to cause the device to: Perform one or more operations including: adjusting the amount of subchannels for the one or more resources, adjusting the amount of retransmissions, adjusting the modulation and coding scheme (MCS), adjusting the communication channel frequency, avoiding sending communications during the CBR window, or a combination thereof.

29. A device configured for wireless communication at a user equipment (UE), the device comprising: One or more processors; And A memory coupled to the one or more processors, wherein instructions are stored in the memory and are executable by the one or more processors to cause the device to: Obtain sidelink channel congestion control information; Determine a CR value for a channel occupancy rate (CR) window based on subchannels used for one or more sidelink resources for a first number of subframes for the history of past transmissions, and based on subchannels estimated for one or more sidelink resources for a second number of subframes for future scheduled transmissions and corresponding retransmissions; And Avoid sending communications during a CBR window associated with the CR window based on the CR value and the sidelink channel congestion control information.

30. The apparatus according to claim 29, wherein The duration of the CR window does not exceed the subframe of the last scheduled retransmission of the future scheduled transmission and the corresponding retransmission.

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