Patent Application
20240237034
The present disclosure relates generally to communication systems, and more particularly, to sidelink (SL) communication.
Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.
These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IOT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC). Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. Some aspects of wireless communication may comprise direct communication between devices based on sidelink. There exists a need for further improvements in sidelink technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.
The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.
In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a first device at a first user equipment (UE). The first device may be a processor and/or modem at the first UE or the first UE itself. The first UE may be configured to receive, from a second UE, a first reservation of an SL resource for a first SL transmission. The first UE may further be configured to receive, from a third UE, a second reservation of the SL resource for a second SL transmission within a threshold amount of time following the receipt of the first reservation. The first UE may also be configured to transmit a collision indication based on a collision parameter, the collision parameter being based on reception of the first reservation and the second reservation within the threshold amount of time.
In another aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a processor and/or modem at a second UE or the second UE itself. The apparatus UE may be configured to transmit an SL reservation for a SL resource, transmit an indication of a capability to receive an expected (or potential) conflict indication, and receive an expected (or potential) conflict indication from a first UE based on the transmitted SL reservation and the indication of the capability to receive an expected (or potential) conflict indication.
To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.
In some aspects of SL communication, devices (e.g., UEs, vehicles, etc.) may autonomously select resources for transmitting SL data. In some instances, UEs may communicate with each other to reserve SL resources for future SL transmissions. At times, collisions may occur between resources reserved by different UEs. Collisions may occur for any of various reasons. As one example, two UEs may be too far apart to receive (or consider relevant) a reservation made by the other UE, but may be close enough that a third UE may receive the SL transmission via the resources reserved by the two UEs. If the two UEs reserve a same SL resource, a conflict or collision may occur and the third UE may not be able to decode either transmission due to the interference. In other examples, one UE may miss, or fail to successfully receive a resource reservation from another UE, yet a third UE may receive the reservation and detect a collision, e.g., an overlap in time and/or frequency between the two reservations. Accordingly, a method for identifying and indicating, by the third UE, collisions or conflicts before they occur is beneficial. Improvements to the sensitivity of the collision detection under different conditions and the reaction time for detecting and indicating a collision are provided herein.
The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.
Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements”). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.
By way of example, an element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on a chip (SoC), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.
Accordingly, in one or more example embodiments, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise a random-access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.
While aspects and implementations are described in this application by illustration to some examples, those skilled in the art will understand that additional implementations and use cases may come about in many different arrangements and scenarios. Innovations described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, implementations and/or uses may come about via integrated chip implementations and other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, artificial intelligence (AI)-enabled devices, etc.). While some examples may or may not be specifically directed to use cases or applications, a wide assortment of applicability of described innovations may occur. Implementations may range a spectrum from chip-level or modular components to non-modular, non-chip-level implementations and further to aggregate, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more aspects of the described innovations. In some practical settings, devices incorporating described aspects and features may also include additional components and features for implementation and practice of claimed and described aspect. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes (e.g., hardware components including antenna, RF-chains, power amplifiers, modulators, buffer, processor(s), interleaver, adders/summers, etc.). It is intended that innovations described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, end-user devices, etc. of varying sizes, shapes, and constitution.
A link between a UE 104 and a base station 102 or 180 may be established as an access link, e.g., using a Uu interface. Other communication may be exchanged between wireless devices based on sidelink. For example, some UEs 104 may communicate with each other directly using a device-to-device (D2D) communication link 158. In some examples, the D2D communication link 158 may use the DL/UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). D2D communication may be through a variety of wireless D2D communications systems, such as for example, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.
Some examples of sidelink communication may include vehicle-based communication devices that can communicate from vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I) (e.g., from the vehicle-based communication device to road infrastructure nodes such as a Road Side Unit (RSU)), vehicle-to-network (V2N) (e.g., from the vehicle-based communication device to one or more network nodes, such as a base station), vehicle-to-pedestrian (V2P), cellular vehicle-to-everything (C-V2X), and/or a combination thereof and/or with other devices, which can be collectively referred to as vehicle-to-anything (V2X) communications. Sidelink communication may be based on V2X or other D2D communication, such as Proximity Services (ProSe), etc. In addition to UEs, sidelink communication may also be transmitted and received by other transmitting and receiving devices, such as Road Side Unit (RSU) 107, etc. Sidelink communication may be exchanged using a PC5 interface, such as described in connection with the example in
Referring again to
The base stations 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC 160 through first backhaul links 132 (e.g., S1 interface). The base stations 102 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN)) may interface with core network 190 through second backhaul links 184. In addition to other functions, the base stations 102 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 may communicate directly or indirectly (e.g., through the EPC 160 or core network 190) with each other over third backhaul links 134 (e.g., X2 interface). The first backhaul links 132, the second backhaul links 184, and the third backhaul links 134 may be wired or wireless.
The base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, the small cell 102′ may have a coverage area 110′ that overlaps the coverage area 110 of one or more macro base stations 102. A network that includes both small cell and macrocells may be known as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs), which may provide service to a restricted group known as a closed subscriber group (CSG). The communication links 120 between the base stations 102 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The base stations 102/UEs 104 may use spectrum up to Y MHZ (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL than for UL). The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell).
The wireless communications system may further include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154, e.g., in a 5 GHz unlicensed frequency spectrum or the like. When communicating in an unlicensed frequency spectrum, the STAs 152/AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.
The small cell 102′ may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102′ may employ NR and use the same unlicensed frequency spectrum (e.g., 5 GHZ, or the like) as used by the Wi-Fi AP 150. The small cell 102′, employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network.
The electromagnetic spectrum is often subdivided, based on frequency/wavelength, into various classes, bands, channels, etc. In 5G NR, two initial operating bands have been identified as frequency range designations FR1 (410 MHZ-7.125 GHZ) and FR2 (24.25 GHZ-52.6 GHZ). Although a portion of FR1 is greater than 6 GHZ, FR1 is often referred to (interchangeably) as a “sub-6 GHz” band in various documents and articles. A similar nomenclature issue sometimes occurs with regard to FR2, which is often referred to (interchangeably) as a “millimeter wave” band in documents and articles, despite being different from the extremely high frequency (EHF) band (30 GHZ-300 GHz) which is identified by the International Telecommunications Union (ITU) as a “millimeter wave” band.
The frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Recent 5G NR studies have identified an operating band for these mid-band frequencies as frequency range designation FR3 (7.125 GHZ-24.25 GHZ). Frequency bands falling within FR3 may inherit FR1 characteristics and/or FR2 characteristics, and thus may effectively extend features of FR1 and/or FR2 into mid-band frequencies. In addition, higher frequency bands are currently being explored to extend 5G NR operation beyond 52.6 GHZ. For example, three higher operating bands have been identified as frequency range designations FR4a or FR4-1 (52.6 GHZ-71 GHz), FR4 (52.6 GHZ-114.25 GHZ), and FR5 (114.25 GHZ-300 GHZ). Each of these higher frequency bands falls within the EHF band.
With the above aspects in mind, unless specifically stated otherwise, it should be understood that the term “sub-6 GHz” or the like if used herein may broadly represent frequencies that may be less than 6 GHZ, may be within FR1, or may include mid-band frequencies. Further, unless specifically stated otherwise, it should be understood that the term “millimeter wave” or the like if used herein may broadly represent frequencies that may include mid-band frequencies, may be within FR2, FR4, FR4-a or FR4-1, and/or FR5, or may be within the EHF band.
A base station 102, whether a small cell 102′ or a large cell (e.g., macro base station), may include and/or be referred to as an eNB, gNodeB (gNB), or another type of base station. Some base stations, such as gNB 180 may operate in a traditional sub 6 GHZ spectrum, in millimeter wave frequencies, and/or near millimeter wave frequencies in communication with the UE 104. When the gNB 180 operates in millimeter wave or near millimeter wave frequencies, the gNB 180 may be referred to as a millimeter wave base station. The millimeter wave base station 180 may utilize beamforming 182 with the UE 104 to compensate for the path loss and short range. The base station 180 and the UE 104 may each include a plurality of antennas, such as antenna elements, antenna panels, and/or antenna arrays to facilitate the beamforming. Similarly, beamforming may be applied for sidelink communication, e.g., between UEs.
The base station 180 may transmit a beamformed signal to the UE 104 in one or more transmit directions 182′. The UE 104 may receive the beamformed signal from the base station 180 in one or more receive directions 182″. The UE 104 may also transmit a beamformed signal to the base station 180 in one or more transmit directions. The base station 180 may receive the beamformed signal from the UE 104 in one or more receive directions. The base station 180/UE 104 may perform beam training to determine the best receive and transmit directions for each of the base station 180/UE 104. The transmit and receive directions for the base station 180 may or may not be the same. The transmit and receive directions for the UE 104 may or may not be the same. Although this example is described for the base station 180 and UE 104, the aspects may be similarly applied between a first and second device (e.g., a first and second UE) for sidelink communication.
The EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be in communication with a Home Subscriber Server (HSS) 174. The MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176. The IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service, and/or other IP services. The BM-SC 170 may provide functions for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS traffic to the base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information. The core network 190 may include an Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 may be in communication with a Unified Data Management (UDM) 196. The AMF 192 is the control node that processes the signaling between the UEs 104 and the core network 190. Generally, the AMF 192 provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF 195. The UPF 195 provides UE IP address allocation as well as other functions. The UPF 195 is connected to the IP Services 197. The IP Services 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a Packet Switch (PS) Streaming (PSS) Service, and/or other IP services.
The base station may include and/or be referred to as a gNB, Node B, eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit reception point (TRP), or some other suitable terminology. The base station 102 provides an access point to the EPC 160 or core network 190 for a UE 104. Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs 104 may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc.). The UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.
Diagram 200 illustrates a single resource block of a single slot transmission, e.g., which may correspond to a 0.5 ms transmission time interval (TTI). A physical sidelink control channel may be configured to occupy multiple physical resource blocks (PRBs), e.g., 10, 12, 15, 20, or 25 PRBs. The PSCCH may be limited to a single sub-channel. A PSCCH duration may be configured to be 2 symbols or 3 symbols, for example. A sub-channel may comprise 10, 12, 15, 20, 25, 50, 75, or 100 PRBs, for example. The resources for a sidelink transmission may be selected from a resource pool including one or more subchannels. As a non-limiting example, the resource pool may include between 1-27 subchannels. A PSCCH size may be established for a resource pool, e.g., as between 10-100% of one subchannel for a duration of 2 symbols or 3 symbols. The diagram 210 in
A resource grid may be used to represent the frame structure. Each time slot may include a resource block (RB) (also referred to as physical RBs (PRBs)) that extends 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme. As illustrated in
The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate mapping matching, onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the device 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318 TX. Each transmitter 318 TX may modulate a radio frequency (RF) carrier with a respective spatial stream for transmission.
At the device 350, each receiver 354 RX receives a signal through its respective antenna 352. Each receiver 354 RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the device 350. If multiple spatial streams are destined for the device 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT). The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by device 310. These soft decisions may be based on channel estimates computed by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by device 310 on the physical channel. The data and control signals are then provided to the controller/processor 359, which implements layer 3 and layer 2 functionality.
The controller/processor 359 can be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. The controller/processor 359 may provide demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing. The controller/processor 359 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.
Similar to the functionality described in connection with the transmission by device 310, the controller/processor 359 may provide RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression/decompression, and security (ciphering, deciphering, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.
Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by device 310 may be used by the TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antenna 352 via separate transmitters 354 TX. Each transmitter 354 TX may modulate an RF carrier with a respective spatial stream for transmission.
The transmission is processed at the device 310 in a manner similar to that described in connection with the receiver function at the device 350. Each receiver 318 RX receives a signal through its respective antenna 320. Each receiver 318 RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.
The controller/processor 375 can be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. The controller/processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing. The controller/processor 375 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.
At least one of the TX processor 368, the RX processor 356, and the controller/processor 359 may be configured to perform aspects in connection with 198 of
At least one of the TX processor 316, the RX processor 370, and the controller/processor 375 may be configured to perform aspects in connection with 198 of
In some aspects of SL communication, devices (e.g., UEs, vehicles, etc.) autonomously select resources for transmitting SL data. In some instances, UEs communicate with each other to reserve SL resources for future SL transmissions. While the UEs may communicate their resource reservations, two UEs may be too far apart to receive (or consider relevant) a reservation made by the other UE, but may be close enough that a third UE may receive the SL transmission via the resources reserved by the two UEs. If the two UEs reserve a same SL resource, a conflict or collision may occur and the third UE may not be able to decode either transmission due to the interference. Accordingly, a method for identifying an indicating, by the third UE, collisions or conflicts before they occur is beneficial. Improvements to the sensitivity of the collision detection under different conditions and the reaction time for detecting and indicating a collision are provided herein.
Sidelink communication may be based on different types or modes of resource allocation mechanisms. In a first resource allocation mode (which may be referred to herein as “Mode 1”), centralized resource allocation may be provided by a network entity. For example, a base station 102 or 180 may determine resources for sidelink communication and may allocate resources to different UEs 104 to use for sidelink transmissions. In this first mode, a UE receives the allocation of sidelink resources from the base station 102 or 180. In a second resource allocation mode (which may be referred to herein as “Mode 2”), distributed resource allocation may be provided. In Mode 2, each UE may autonomously determine resources to use for sidelink transmission. In order to coordinate the selection of sidelink resources by individual UEs, each UE may use a sensing technique to monitor for resource reservations by other sidelink UEs and may select resources for sidelink transmissions from unreserved resources. Devices communicating based on sidelink, may determine one or more radio resources in the time and frequency domain that are used by other devices in order to select transmission resources that avoid collisions with other devices. The sidelink transmission and/or the resource reservation may be periodic or aperiodic, where a UE may reserve resources for transmission in a current slot and up to two future slots (discussed below).
Thus, in the second mode (e.g., Mode 2), individual UEs may autonomously select resources for sidelink transmission, e.g., without a central entity such as a base station indicating the resources for the device. A first UE may reserve the selected resources in order to inform other UEs about the resources that the first UE intends to use for sidelink transmission(s).
In some examples, the resource selection for sidelink communication may be based on a sensing-based mechanism. For instance, before selecting a resource for a data transmission, a UE may first determine whether resources have been reserved by other UEs.
For example, as part of a sensing mechanism for resource allocation mode 2, the UE may determine (e.g., sense) whether the selected sidelink resource has been reserved by other UE(s) before selecting a sidelink resource for a data transmission. If the UE determines that the sidelink resource has not been reserved by other UEs, the UE may use the selected sidelink resource for transmitting the data, e.g., in a PSSCH transmission. The UE may estimate or determine which radio resources (e.g., sidelink resources) may be in-use and/or reserved by others by detecting and decoding sidelink control information (SCI) transmitted by other UEs. The UE may use a sensing-based resource selection algorithm to estimate or determine which radio resources are in-use and/or reserved by others. The UE may receive SCI from another UE that includes reservation information based on a resource reservation field comprised in the SCI. The UE may continuously monitor for (e.g., sense) and decode SCI from peer UEs. The SCI may include reservation information, e.g., indicating slots and RBs that a particular UE has selected for a future transmission. The UE may exclude resources that are used and/or reserved by other UEs from a set of candidate resources for sidelink transmission by the UE, and the UE may select/reserve resources for a sidelink transmission from the resources that are unused and therefore form the set of candidate resources. The UE may continuously perform sensing for SCI with resource reservations in order to maintain a set of candidate resources from which the UE may select one or more resources for a sidelink transmission. Once the UE selects a candidate resource, the UE may transmit SCI indicating its own reservation of the resource for a sidelink transmission. The number of resources (e.g., sub-channels per subframe) reserved by the UE may depend on the size of data to be transmitted by the UE. Although the example is described for a UE receiving reservations from another UE, the reservations may also be received from an RSU or other device communicating based on sidelink.
A first UE (“UE1) may reserve a sub-channel (e.g., SC 1) in a current slot (e.g., slot 1) for its initial data transmission 502, and may reserve additional future slots within the window for data retransmissions (e.g., 504 and 506). For example, UE1 may reserve sub-channels SC 3 at slots 3 and SC 2 at slot 4 for future retransmissions as shown by
A third UE may consider resources reserved by other UEs within the resource selection window to select resources to transmit its data. The third UE may first decode SCIs within a time period to identify which resources are available (e.g., candidate resources). For example, the third UE may exclude the resources reserved by UE1 and UE2 and may select other available sub-channels and time slots from the candidate resources for its transmission and retransmissions, which may be based on a number of adjacent sub-channels in which the data (e.g., packet) to be transmitted can fit.
While
The UE may determine an associated signal measurement (such as reference signal received power (RSRP)) for each resource reservation received by another UE. The UE may consider resources reserved in a transmission for which the UE measures an RSRP below a threshold to be available for use by the UE. A UE may perform signal/channel measurement for a sidelink resource that has been reserved and/or used by other UE(s), such as by measuring the RSRP of the message (e.g., the SCI) that reserves the sidelink resource. Based at least in part on the signal/channel measurement, the UE may consider using/reusing the sidelink resource that has been reserved by other UE(s). For example, the UE may exclude the reserved resources from a candidate resource set if the measured RSRP meets or exceeds the threshold, and the UE may consider a reserved resource to be available if the measured RSRP for the message reserving the resource is below the threshold. The UE may include the resources in the candidate resources set and may use/reuse such reserved resources when the message reserving the resources has an RSRP below the threshold, because the low RSRP indicates that the other UE is distant and a reuse of the resources is less likely to cause interference to that UE. A higher RSRP indicates that the transmitting UE that reserved the resources is potentially closer to the UE and may experience higher levels of interference if the UE selected the same resources.
For example, in a first step, the UE may determine a set of candidate resources (e.g., by monitoring SCI from other UEs and removing resources from the set of candidate resources that are reserved by other UEs in a signal for which the UE measures an RSRP above a threshold value). In a second step, the UE may select N resources for transmissions and/or retransmissions of a TB. As an example, the UE may randomly select the N resources from the set of candidate resources determined in the first step. In a third step, for each transmission, the UE may reserve future time and frequency resources for an initial transmission and up to two retransmissions. The UE may reserve the resources by transmitting SCI indicating the resource reservation. For example, in the example in
Diagrams 720-740 illustrate examples of conflicting (colliding) transmissions 712 and 714 received from UEA 702 and UEB 704. Diagram 720 illustrates that UEC 706 may receive SL control information (SCI) 721 and 722 transmitted by UEA 702 and UEB 704, respectively. Each grid of diagrams 720-740 represents a resource grid. As illustrated each block is identified as a selectable resource 729 (e.g., time-and-frequency resources, a subchannel (e.g., an RB or some other grouping of resources)). The SCI 721 and 722 transmitted by UEA 702 and UEB 704, as shown, each include resource reservation information for two reserved time-and-frequency resources including a set of time-and-frequency resources overlapping in time and frequency (e.g., in the selectable resource identified as an expected/potential conflict 723). As will be discussed below in relation to diagram 740 a conflict between SL transmissions for UEs performing half-duplex communication may be based on resource reservation information for a set of time-and-frequency resources overlapping in time but not frequency that may be included in SCI transmitted by UEA 702 and UEB 704 (not shown).
Based on the SCI 721 and 722. UEC 706 may detect the expected/potential conflict 723 before UEA 702 and UEB 704 transmit the data in the overlapping set of time-and-frequency resources. As will be discussed below, the detection may also include measuring at least one of a reference signal received power (RSRP) for each of the transmissions 712 and 714 from UEA 702 and UEB 704, respectively, or measuring a reference signal received quality (RSRQ) for at least one of the transmissions 712 and 714 from UEA 702 and UEB 704, respectively. As will be discussed below, the detection may further include determining at least one of (1) an absolute value or magnitude of an RSRP difference or ratio between the transmissions 712 and 714 from UEA 702 and UEB 704, respectively, or (2) a measured RSRQ for at least one of the transmissions from UEA 702 and UEB 704. For a first example, if UEC 706 measures RSRPs for transmissions 712 and 714 as −80 dBm and −83 dBm and an absolute RSRP difference threshold for identifying conflicts is 10 dB (representing approximately a ten-fold difference in signal strengths), the transmissions 712 and 714 would be determined to be conflicting based on the absolute RSRP difference of 3 dB (representing approximately a two-fold difference). However, if UEC 706 measures RSRPs for transmissions 712 and 714 as −80 dBm and −93 dBm (i.e., an absolute RSRP difference of 10 dBm, representing an approximately twenty-fold difference in signal strength) and the absolute RSRP difference threshold for identifying conflicts is 10 dBm, the transmissions 712 and 714 would be determined to not be conflicting. In some aspects, UEC 706 measures an RSRQ for at least one of transmissions 712 and 714 and applies an RSRQ threshold for identifying conflicts of 0.95 (representing a ratio of 0.95 between an RSRP for the reference signal for the measured transmission and a received signal strength indicator (RSSI) (a measure of total received wide-band power) measured at the UE) to determine whether the transmissions 712 and 714 conflict.
As will be further discussed below in relation to
Based on a detected potential conflict, or collision (e.g., for resource identified as potential conflict 723), UEC 706 may transmit, to at least one of UEA 702 and UEB 704, an expected/potential conflict indication 725. The expected/potential conflict indication 725 may be transmitted to UEB 704 and may include information regarding the resources reserved by UEA 702 (e.g., the reserved resources or at least the overlapping resources) or may indicate a collision associated with the SCI (e.g., SCI 722) transmitted by UEB 704. UEB 704 may receive the expected/potential conflict indication 725 and determine to cancel the transmission 727 in the set of time-and-frequency resources overlapping with the transmission from UEA 702 (e.g., in the time-and-frequency resource identified as a potential conflict 723). The data meant to be transmitted during the set of overlapping time-and-frequency resource may then be transmitted based on per-packet scheduling.
Diagram 730 illustrates that UEC 706 may receive conflicting (colliding) transmissions at a time-and-frequency resource identified as including a collision 733. Based on receiving the conflicting (colliding) transmissions, UEC 706 may transmit a post-collision indication 735. The post-collision indication 735 may be transmitted to UEA 702 and UEB 704 and may include information indicating that at least one of (1) RSRPs measured at UEC 706 or (2) at least one RSRQ measured at UEC 706 indicate a conflict between the transmissions 712 and 714. UEA 702 and UEB 704 may receive the post-collision indication 735 and determine to re-transmit 737 the colliding transmissions. Since the re-transmission resource is selected by each of UEA 702 and UEB 704 based on different information or input (e.g., a randomly generated value, or a UE-specific value) it is unlikely for there to be a subsequent collision, but in the event that a collision occurs on the re-transmission, the same process may be repeated.
Diagram 740 illustrates that UEC 706 may receive conflicting (colliding) transmissions at different time-and-frequency resources at a same time, the conflicting resources identified as including a half-duplex collision 743. The conflict illustrated in diagram 740 is based on an overlap in transmission time that prevents UEA 702 and UEB 704 from receiving the transmission from UEB 704 and UEA 702, respectively (e.g., because they are operating in a half-duplex mode). Based on transmissions associated with the half-duplex collision 743, UEC 706 may transmit a post-collision half-duplex conflict indication 745. The post-collision half-duplex conflict indication 745 may be transmitted to UEA 702 and UEB 704 and may include information indicating that UE A and UE B cannot receive data from each other. UEA 702 and UEB 704 may receive the post-collision half-duplex conflict indication 745 and determine to re-transmit 747 the colliding transmissions. Since the re-transmission resource is selected by each of UEA 702 and UEB 704 based on different information or input (e.g., a randomly generated value, or a UE-specific value) it is unlikely for there to be a subsequent collision, but in the event that a collision occurs on the re-transmission, the same process may be repeated.
The UEx 804 may process the received SCI during a time interval Tfwd,1 between ‘SCI received’ 801 and ‘SCI processed’ 803. The processing performed by the UEx 804 may include decoding the SCI received at ‘SCI received’ 801 and determining the reserved resource (e.g., resource X 823). Based on the determination of the reserved resource (e.g., resource X 823), the UEx 804 may generate (e.g., between ‘SCI processed’ 803 and ‘IUC formed’ 805) an IUC message indicating the reserved resource to a set of other UEs (e.g., including the second UEB 802). After generating (e.g., forming) the IUC message at ‘IUC formed’ 805, the IUC message may be encoded at ‘IUC encoded’ 807 and transmitted to the set of other UEs (e.g., including the second UEB 802). The IUC generation and encoding may span a second time interval Tfwd,2. The IUC message may be included in a PSCCH symbol/resource, a PSSCH symbol/resource, or a feedback (e.g., PSFCH) symbol and may include less data than SCI including a reservation. The second UEB 802 may receive the IUC message at ‘IUC reception’ 811 a time interval Tfwd,3 after the IUC encoding at ‘IUC encoded’ 807. During a next time interval Tfwd,4, the second UEB 802 may process the IUC message to identify the reserved resource and may complete the processing at ‘IUC processed’ 813.
As shown, the time ‘IUC received’ 811 may be after a sensing window ends (e.g., sensing window 602 of
The number of independent PSFCH resources in a PSFCH resource set 1111 or 1115 and/or in the expected/potential conflict indication resource set 1113 and/or 1115 may be increased by enabling the use of “Y” different cyclic shifts (e.g., 1, 2, 3, 4, or 6 different cyclic shifts) for transmitting HARQ feedback and/or an expected/potential conflict indication in each frequency resource (e.g., set of PRBs, PRB, or set of subcarriers) in the PSFCH resource set and/or the expected/potential conflict indication resource set. The different cyclic shifts may enable a device receiving the HARQ feedback to identify HARQ feedback transmitted from multiple other devices (e.g., devices receiving a groupcast transmission) using a same frequency resource.
In some aspects a UE may expect that a slot tkSL has a (pre- or post-) collision indication transmission occasion resource if k mod NPSSCHEPCI=0, where tkSL is defined as above and NPSSCHEPCI (or some other value indicating a EPCI resource pool periodicity in slots) is provided by a particular parameter, e.g., a parameter for specifying the periodicity of the expected/potential conflict indication resource slots (e.g., an sl-PCI-Period-r16 parameter). If a UE receives a PSSCH or PSCCH (e.g., including SCI) in a resource triggering an expected/potential conflict indication, the UE may provide the expected/potential conflict indication in an expected/potential conflict indication resource in the expected/potential conflict resource set when the trigger condition is met. The UE may transmit the collision indication in a first slot that includes expected/potential conflict indication resources of the resource set after a last slot of the PSSCH reception or after a slot during which the collision indication is triggered. Although an example is provided to illustrate the concept for an expected/potential conflict indication, the aspects may be similarly applied to a post-collision indication.
In some aspects, the minimum time gap for an expected/potential conflict indication (e.g., minimum time gap 1311), in some aspects, is one of the same as, or different from, a minimum time gap for a PSFCH. Increasing the frequency (e.g., decreasing the period) of the expected/potential conflict indication resource pools and/or decreasing a minimum time gap for an expected/potential conflict indication may make the expected/potential conflict indication more effective. For example, the Tfwd (e.g., between the time ‘SCI received’ 801 and the time ‘IUC processed’ 813) may be reduced as the expected/potential conflict indication may be provided more quickly and allow a UE reserving a conflicting/colliding resource to adjust the transmission of the SL transmission.
The UE 1306 may transmit, and the UE 1304 may receive, an SL resource reservation 1310 for a particular SL resource. The UE 1302 may subsequently transmit, and the UE 1304 may receive, a second SL resource reservation 1312 for the particular SL resource (or an SL resource during a same slot but at a different frequency subchannel/resource). The second SL resource reservation 1312 may include a capability indication indicating a capability to receive an expected/potential conflict indication. The capability indication may be transmitted and/or received via a capability bit included in SCI. In some aspects, the capability indication may be (implicitly) received at the UE 1304 based on a transmission or signal from the UE 1302 that indicates that the UE 1302 supports a particular set of capabilities including the capability to receive an expected/potential conflict indication. For example, if the second SL resource reservation 1312 (or some other transmission from UE 1302) includes a transmission specific to a particular release of the 3GPP standard or later that includes the capability to receive an expected/potential conflict indication, the UE 1304 may determine that the UE 1302 is capable of receiving an expected/potential conflict indication.
The UE 1304 may determine 1314 that the SL resource reservations 1310 and 1312 are for colliding SL resources (e.g., a same SL resource or SL resources during a same slot). As discussed below, the UE 1304 may determine 1314 that the SL resource reservations conflict/collide based on a relative power between the received first SL resource reservation 1310 and the received second SL resource reservation 1312 being within a particular relative power threshold range from multiple relative power threshold ranges for reservations of a same SL resource (or otherwise conflicting/colliding SL resources). As will be described below in relation to
After the UE 1304 determines 1314 that the SL resource reservations conflict/collide, the UE 1304 may transmit an expected/potential conflict indication 1316. As illustrated for the expected/potential conflict indication 1316, the expected/potential conflict indication resource 1319, in some aspects, may not be used to transmit the expected/potential conflict indication 1316 despite the UE 1304 determining 1314 that the SL resource reservations conflict/collide before the expected/potential conflict indication resource 1319. In some aspects, the expected/potential conflict indication 1316 is not transmitted via the expected/potential conflict indication resource 1319 because the determination does not precede the expected/potential conflict indication resource 1319 by a minimum time gap 1311. Instead, the expected/potential conflict indication 1316, in some aspects, may be transmitted via an immediately subsequent expected/potential conflict indication resource 1329. In some aspects, an expected/potential conflict indication based on a determination that SL resource reservations conflict/collide that is made after a first expected/potential (e.g., expected/potential conflict indication resource 1319) conflict indication resource and before a next expected/potential conflict indication resource (e.g., expected/potential conflict indication resource 1329) is transmitted during the next expected/potential conflict indication resource. For example, if a determination that SL resource reservations conflict/collide precedes the next expected/potential conflict indication resource by the minimum time gap 1311, the expected/potential conflict indication may be transmitted via the next expected/potential conflict indication resource.
The UE 1604 may determine 1612 that the SL resource reservations 1608 and 1610 are for conflicting or colliding SL resources based on the time difference 1609. In some aspects, a collision may refer to SL resource reservations for a same time-and-frequency resource, while a conflict may refer to SL resource reservations for SL resources having different frequencies (e.g., subchannels) at a same time, e.g., within a same slot. In some aspects, a collision may be detected if the RSRPs of the colliding reservations are within a γth dB of each other, with γth representing a threshold RSRP difference. As an example, when the reservations are received within a threshold amount of time, the UE may send feedback if an RSRP of the received reservations are within γth,close of each other, with γth,close>γth. The UE 1604 may determine 1612 that the SL resource reservations collide based on a relative power between the received first SL resource reservation 1608 and the received second SL resource reservation 1610 being within a particular relative power threshold range of multiple relative power threshold ranges for reservations of a same SL resource (or for conflicting SL resources). The relative power threshold range may depend on one or more factors including a time difference between reception of the conflicting and/or colliding SL resource reservations, an MCS associated with each of the SL resource reservations, whether the resources overlap in both time and frequency or just in time, and a distance between the UEs.
In some aspects, the particular relative power threshold range may be based on the time difference 1609. Each relative power threshold range of the multiple relative power threshold ranges may be associated with a particular range of time differences between SL resource reservations for conflicting or colliding SL resources. For example, a first range of time differences including times longer than a time Tfwd+Tproc,0+T3 (as defined above in relation to
In some aspects, keeping all other factors besides the time difference on which the particular relative power threshold range constant, the first relative power threshold range may include a smaller range of relative powers (e.g., may be a less aggressive conflict identification), while the second relative power threshold range may include a larger range of relative powers than the first relative power threshold range, and the third relative power threshold range includes a larger range of relative powers than both the first relative power threshold range and second relative power threshold range. A relative power threshold range, in some aspects, may be based on a magnitude of the relative power between transmissions (e.g., transmitted SCI) associated with the first and second SL resource reservations. A range may be provided between [γ1, γ2], for example. As one, non-limiting example, a range may be between −3 dB and 3 dB) of the relative power between transmissions (e.g., transmitted SCI) associated with the first and second SL resource reservations. As an example, when the reservations are received within a threshold amount of time, the UE may send feedback if an RSRP of the received reservations are within a range [γ1,close, γ2,close], and γ1,close<γ1<γ2<γ2,close.
The factors affecting the relative power threshold range, in some aspects, may include the MCS associated with at least one of a first SCI (e.g., SCI-1), a second SCI (e.g., SCI-2), or data associated with the first or second SCI. For example, the relative power threshold range for SL reservations associated with an MCS with a higher signal to interference and noise ratio (SINR) threshold for decoding a transmission may be larger (may identify more collisions/conflict) than a relative power threshold range associated with an MCS with a lower SINR threshold for decoding a transmission. Additionally, if there is a mismatch between the MCS associated with a first SL resource reservation and a the MCS associated with a second SL resource reservation the relative power threshold range may be asymmetric about 0 (an upper bound of the range may have a greater magnitude than a lower bound of the range or vice versa)
In some aspects, the relative power threshold range may depend on whether the collision is based on a reservation of a same SL resource (e.g., a collision) or of SL resources during a same slot via different frequency subchannels (e.g., a half-duplex collision or a conflict based on leakage). For example, a relative power threshold, e.g., a relative power threshold value (as opposed to a relative power threshold range) of approximately ±24-30 dB between a first SL resource reservation for a first time-and-frequency resource and a second SL resource reservation for a second time-and-frequency resource overlapping in time, but not frequency, with the first resource, may have a greater magnitude than an upper bound, e.g., approximately 3 dB, or a lower bound, e.g., approximately −3 dB, of a relative power threshold range for colliding reservations. The different magnitude and the use of a threshold value (e.g., a range with either an upper or lower bound) for identifying the conflict may be based on concern for leakage between one frequency (e.g., subchannel) and another frequency (e.g., an adjacent subchannel) that occurs when a power associated with one transmission is so much greater than another that the leakage may cause interference.
The relative power threshold, in some aspects, may further be based on a distance between the UE 1602 transmitting the SL resource transmission 1610, the UE 1606 transmitting the SL resource reservation 1608, and/or the UE 1606 receiving the SL resource reservations 1608 and 1610. For example, if a distance is smaller than a threshold distance, ‘d’, the relative power threshold may be smaller than for a distance that is larger than the distance ‘d’. The distance ‘d’ may be estimated or determined based on zone information or location information when available.
After the UE 1604 determines 1612 that the SL resource reservations 1608 and 1610 collide and/or conflict, the UE 1604 may transmit, and UE 1602 may receive, expected/potential conflict indication 1614. The UE 1604 may transmit the expected/potential conflict indication to the UE 1602 based on a UE capability indication transmitted by the UE 1602 (e.g., included in SL resource reservation 1610 or previously transmitted SCI). If UE 1602 has not indicated that it is capable of receiving (e.g., processing or interpreting) an expected/potential conflict indication, but UE 1606 has indicated a capability of receiving an expected/potential conflict indication an expected/potential conflict indication may be transmitted to UE 1606 instead of UE 1602 as discussed in relation to skipped expected/potential conflict indication 1624. In some aspects, even if both UEs are capable of receiving an expected/potential conflict indication, the UE 1604 may transmit the expected/potential conflict indication to a previously reserving UE (e.g., the UE 1606 in call flow diagram 1600) based on a relative priority of the transmissions for which the SL resources have been reserved (e.g., the earlier-reserved resources being associated with a lower priority transmission than the later-reserved resources).
After transmitting expected/potential conflict indication 1614, the UE 1602 may transmit, and the UE 1604 may receive, a third SL resource reservation 1616. The UE 1606 may subsequently transmit, and the UE 1604 may receive, a fourth SL resource reservation 1618 for a conflicting or colliding SL resource at a time that is after receiving the third SL resource reservation 1616 by time difference 1617. The UE 1604 may determine 1620 that the SL resource reservations collide based on a relative power between the received third SL resource reservation 1616 and the received fourth SL resource reservation 1618 being within a particular relative power threshold range that may be different from the relative power threshold range used to determine 1612 that the first and second SL resource reservations collide. The different relative power threshold range may depend on the one or more factors discussed above.
After the UE 1604 determines 1620 that the SL resource reservations 1616 and 1618 collide and/or conflict, the UE 1604 may skip transmission of an expected/potential conflict indication 1624 to UE 1602 based on one or more factors (e.g., conditions) for not transmitting an expected/potential conflict indication. In some aspects, the distance between UEs, discussed above as a factor for a relative power threshold range, may be considered as a factor and/or a criteria for whether to skip an expected/potential conflict indication. For example, if a distance from the UE 1604 to at least one of the UE 1602 or the UE 1606 making the SL resource reservations is below a threshold distance, the UE 1604 may skip transmission of an expected/potential conflict indication.
In some aspects, skipping an expected/potential conflict indication may also be based on a received power of the SL resource reservation. For example, an SL resource reservation associated with a UE is received with a power (e.g., RSRP) that is within a range of powers indicating that a collision indication may interfere with sidelink feedback, a UE may skip transmission of an expected/potential conflict indication. The interference may be due to the UE receiving the expected/potential conflict indication with a power that is much greater than a feedback message transmitted in a same symbol by a more distant UE such that the leakage from the (pre- or post-) collision indication resources to the PSFCH resources interferes with the reception of the PSFCH resources. In some aspects, the expected/potential conflict indication may be skipped based on the SL resource reservations being for a SL communication having been transmitted at least a threshold number of times. For example, an Nth transmission of a SL communication (e.g., an (N−1)th retransmission), where N is greater than a threshold number ‘k’, may not trigger an expected/potential conflict indication. The threshold number ‘k’ may be based on the time difference between the reception of a first and second SL resource reservation as described above in relation to the relative power threshold where k is greater for SL resource reservations received closer in time than for SL resource reservations farther apart in time. For example, Kclose may be used if the reservations are received with a time gap within the threshold amount of time, and k may be used if the reservations are received with a larger time gap, where kclose>k.
Although an example for expected/potential conflict indication is described in order to illustrate the concepts, aspects may be applied for post-collision indications, as well.
At 1704, the first UE may receive, from a third UE, a second reservation of the SL resource for a second SL transmission within a threshold amount of time following the receipt of the first reservation. In some aspects, at least one of the second UE and the third UE may also transmit an indication of a capability relating to collision indication, such as a capability to receive an expected/potential conflict indication. The indication, in some aspects, is transmitted along with the SL resource reservation. For example, referring to
At 1706, the first UE may transmit a collision indication based on a collision parameter, the collision parameter being based on reception of the first reservation and the second reservation within the threshold amount of time. In some aspects, the UE may transmit an expected/potential conflict indication based on the collision parameter. In some aspects, the UE may transmit a post-collision indication based on the collision parameter. For example, 1706 may be performed by SL collision detection component 2142 and SL collision reporting component 2144. As discussed above, in relation to
Each relative power threshold range of the multiple relative power threshold ranges, in some aspects, may be associated with a distinct range of times between different reservations for a same SL resource. In some aspects, the (applied) relative power threshold range may be associated with a first range of times including the threshold amount of time and includes a larger range of relative powers than another relative power threshold range associated with a second range of times that are greater than the times included in the first range of times. As discussed above in relation to the relative power threshold range being based on an MCS, each relative power threshold range of the multiple relative power threshold ranges maybe determined based on at least one of an ability to decode data on the reserved SL resource, an ability to decode a first type of sidelink control information (SCI), or an ability to decode a second type of SCI.
In some aspects, the first UE may receive an indication of a collision indication reception capability of the second UE and the (pre-)collision indication may be transmitted to the second UE. The (pre-)collision indication may be transmitted to the second UE based on a priority associated with the second SL transmission. As discussed above, the indication of the collision indication reception capability of the second UE may be received via a reserved bit in SCI.
The first UE may transmit the expected/potential conflict indication in a first slot having expected/potential conflict resources of a resource pool and being at least a minimum time gap after a last slot in which a colliding reservation is received. The periodicity of the expected/potential conflict indication resource, in some aspects, may be a same periodicity as a feedback resource periodicity or may be different from a periodicity of a feedback resource periodicity. Additionally, in some aspects, a minimum time gap for an expected/potential conflict indication is less than a minimum time gap for feedback. Accordingly, in some aspects, the collision indication resource following the received reservation for the SL resource by at least the minimum time gap may precede an SL feedback resource following the reservation for the SL resource by at least the minimum time gap for feedback. In some aspects, the minimum time gap for an expected/potential conflict indication is less than one slot (e.g., 1-13 symbols of a 14-symbol slot).
At 1804, the first UE may receive, from a third UE, a second reservation of the SL resource for a second SL transmission within a threshold amount of time following the receipt of the first reservation. For example, referring to
In some aspects, at least one of the second UE and the third UE may also transmit an indication of a capability to receive an expected/potential conflict indication. The indication, in some aspects, is transmitted along with the SL resource reservation. At 1806, the first UE may receive an indication of a collision indication reception capability of the second UE. The indication of the collision indication reception capability of the second UE may be received via a reserved bit in SCI. In some aspects, the capability indication may be (implicitly) received at the first UE based on a transmission or signal from the second or third UE that indicates that the second or third UE supports a particular set of capabilities including the capability to receive an expected/potential conflict indication. For example, referring to
At 1808, the first UE may transmit a collision indication based on a collision parameter, the collision parameter being based on reception of the first reservation and the second reservation within the threshold amount of time. For example, 1808 may be performed by SL collision detection component 2142 and SL collision reporting component 2144. As discussed above, in relation to
Each relative power threshold range of the multiple relative power threshold ranges, in some aspects, may be associated with a distinct range of times between different reservations for a same SL resource. In some aspects, the (applied) relative power threshold range may be associated with a first range of times including the threshold amount of time and includes a larger range of relative powers than another relative power threshold range associated with a second range of times that are greater than the times included in the first range of times. As discussed above in relation to the relative power threshold range being based on an MCS, each relative power threshold range of the multiple relative power threshold ranges maybe determined based on at least one of an ability to decode data on the reserved SL resource, an ability to decode a first type of sidelink control information (SCI), or an ability to decode a second type of SCI.
In some aspects, the first UE may receive an indication of a collision indication reception capability of the second UE and the (pre-)collision indication may be transmitted to the second UE. The (pre-)collision indication may be transmitted to the second UE based on a priority associated with the second SL transmission. As discussed above, the indication of the collision indication reception capability of the second UE may be received via a reserved bit in SCI.
The first UE may transmit the collision indication in a first slot having expected/potential conflict resources of a resource pool and being at least a minimum time gap after a last slot in which a colliding reservation is received. The periodicity of the expected/potential conflict indication resource, in some aspects, may be a same periodicity as a feedback resource periodicity or may be different from a periodicity of a feedback resource periodicity. Additionally, in some aspects, a minimum time gap for an expected/potential conflict indication is less than a minimum time gap for feedback. Accordingly, in some aspects, the collision indication resource following the received reservation for the SL resource by at least the minimum time gap may precede an SL feedback resource following the reservation for the SL resource by at least the minimum time gap for feedback. In some aspects, the minimum time gap for an expected/potential conflict indication is less than one slot (e.g., 1-13 symbols of a 14-symbol slot).
At 1810, the first UE may receive, from a fourth UE, a third reservation of an SL resource for a third SL transmission. For example, referring to
At 1812, the first UE may receive, from a fifth UE, a fourth reservation of the SL resource for a fourth SL transmission within a threshold amount of time following the receipt of the third reservation. For example, referring to
At 1814, the first UE may skip transmission of a collision indication based on a collision of the third reservation and the fourth reservation based on an occurrence of a condition for not transmitting a collision indication. As discussed above, the condition for not transmitting a collision indication may be at least one of (1) a distance to at least one of the third UE or the fourth UE being below a threshold distance, (2) a measured power of at least one of the third reservation and the fourth reservation being within a range of powers indicating that a collision indication may interfere with sidelink feedback, or (3) both the third reservation and the fourth reservation being for periodic transmissions having been transmitted at least a threshold number of times. In some aspects, the distance between the third UE or the fourth UE may be determined based on at least one of (1) zone information associated with the first UE and at least one of the third UE or the fourth UE or (2) location information associated with the first UE and at least one of the third UE or the fourth UE. For example, referring to
At 1904, the first UE may configure a minimum time gap for expected/potential conflict indication that is different from a minimum time gap for feedback. For example, referring to
At 1906, the first UE may receive a reservation for an SL resource that reserves a same SL resource as a previously received reservation for an SL resource. In some aspects, at least one of the second UE and the third UE may also transmit an indication of a capability to receive an expected/potential conflict indication. The indication, in some aspects, is transmitted along with the SL resource reservation. For example, referring to
At 1908, the first UE may transmit, based on receiving the reservation for the SL resource, an expected/potential conflict indication via an expected/potential conflict indication resource following the received reservation for the SL resource by at least the minimum time gap. In some aspects, the expected/potential conflict indication may be based on a collision parameter, the collision parameter being based on reception of the first reservation and the second reservation within the threshold amount of time. For example, 1908 may be performed by SL collision detection component 2142 and SL collision reporting component 2144. As discussed above, in relation to
Each relative power threshold range of the multiple relative power threshold ranges, in some aspects, may be associated with a distinct range of times between different reservations for a same SL resource. In some aspects, the (applied) relative power threshold range may be associated with a first range of times including the threshold amount of time and includes a larger range of relative powers than another relative power threshold range associated with a second range of times that are greater than the times included in the first range of times. As discussed above in relation to the relative power threshold range being based on an MCS, each relative power threshold range of the multiple relative power threshold ranges maybe determined based on at least one of an ability to decode data on the reserved SL resource, an ability to decode a first type of sidelink control information (SCI), or an ability to decode a second type of SCI.
In some aspects, the first UE may receive an indication of an expected/potential conflict indication reception capability of the second UE and the (pre-) collision indication may be transmitted to the second UE. The (pre-)collision indication may be transmitted to the second UE based on a priority associated with the second SL transmission. As discussed above, the indication of the collision indication reception capability of the second UE may be received via a reserved bit in SCI.
The first UE may transmit the expected/potential conflict indication in a first slot having expected/potential conflict resources of a resource pool and being at least a minimum time gap after a last slot in which a colliding reservation is received. The periodicity of the expected/potential conflict indication resource, in some aspects, may be a same periodicity as a feedback resource periodicity or may be different from a periodicity of a feedback resource periodicity. Additionally, in some aspects, a minimum time gap for an expected/potential conflict indication is less than a minimum time gap for feedback. Accordingly, in some aspects, the expected/potential conflict indication resource following the received reservation for the SL resource by at least the minimum time gap may precede an SL feedback resource following the reservation for the SL resource by at least the minimum time gap for feedback. In some aspects, the minimum time gap for an expected/potential conflict indication is less than one slot (e.g., 1-13 symbols of a 14-symbol slot).
At 2004, the second UE may transmit an indication of a capability to receive an expected/potential conflict indication. For example, referring to
At 2006, the second UE may receive, based on the transmitted SL reservation and the indication of the capability to receive an expected/potential conflict indication, an expected/potential conflict indication from a first UE. For example, referring to
The communication manager 2132 includes an SL resource reservation component 2140 that is configured to receive and transmit SL resource reservations and to transmit and receive an indication of a capability to receive an expected/potential conflict indication, e.g., as described in connection with 1702, 1704, 1802, 1804, 1806, 1810, 1812, 1906, 2002, 2004, and 2006 of
The apparatus may include additional components that perform each of the blocks of the algorithm in the flowcharts of
In one configuration, the apparatus 2102, and in particular the baseband processor 2104, includes means for receiving, from a second UE, a first reservation of an SL resource for a first SL transmission. The apparatus 2102, and in particular the baseband processor 2104, may further include means for receiving, from a third UE, a second reservation of the SL resource for a second SL transmission within a threshold amount of time following the receipt of the first reservation. The apparatus 2102, and in particular the baseband processor 2104, may further include means for transmitting a collision indication based on a collision parameter, where the collision parameter is based on receiving the second reservation within the threshold amount of time following the reception of the first reservation. The apparatus 2102, and in particular the baseband processor 2104, may further include means for receiving an indication of a collision indication reception capability of the second UE. The apparatus 2102, and in particular the baseband processor 2104, may further include means for receiving, from a fourth UE, a third reservation of an additional SL resource for a third SL transmission. The apparatus 2102, and in particular the baseband processor 2104, may further include means for receiving, from a fifth UE, a fourth reservation of the additional SL resource for a fourth SL transmission within a particular time before the additional SL resource. The apparatus 2102, and in particular the baseband processor 2104, may further include means for skipping transmission of a collision indication based on a collision of the third reservation and the fourth reservation based on an occurrence of a condition for not transmitting a collision indication. The apparatus 2102, and in particular the baseband processor 2104, may further include means for transmitting an SL reservation for an SL resource. The apparatus 2102, and in particular the baseband processor 2104, may further include means for transmitting an indication of a capability to receive an expected conflict indication. The apparatus 2102, and in particular the baseband processor 2104, may further include means for receiving, based on the transmitted SL reservation and the indication of the capability to receive an expected/potential conflict indication, an expected conflict indication from a first UE. The apparatus 2102, and in particular the baseband processor 2104, may further include means for configuring a periodicity of an expected conflict indication resource. The apparatus 2102, and in particular the baseband processor 2104, may further include means for configuring a minimum time gap for expected conflict indication that is different from a minimum time gap for feedback. The apparatus 2102, and in particular the baseband processor 2104, may further include means for receiving a reservation for an SL resource that reserves a same SL resource as a previously received reservation for an SL resource. The apparatus 2102, and in particular the baseband processor 2104, may further include means for transmitting, based on receiving the reservation for the SL resource, an expected conflict indication via an expected conflict indication resource following the received reservation for the SL resource by at least the minimum time gap. The means may be one or more of the components of the apparatus 2102 configured to perform the functions recited by the means. As described herein, the apparatus 2102 may include the TX Processor 368, the RX Processor 356, and the controller/processor 359. As such, in one configuration, the means may be the TX Processor 368, the RX Processor 356, and the controller/processor 359 configured to perform the functions recited by the means.
It is understood that the specific order or hierarchy of blocks in the processes/flowcharts disclosed is an illustration of example approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes/flowcharts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in a sample order, and are not meant to be limited to the specific order or hierarchy presented.
The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Terms such as “if,” “when,” and “while” should be interpreted to mean “under the condition that” rather than imply an immediate temporal relationship or reaction. That is, these phrases, e.g., “when,” do not imply an immediate action in response to or during the occurrence of an action, but simply imply that if a condition is met then an action will occur, but without requiring a specific or immediate time constraint for the action to occur. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. The words “module,” “mechanism,” “element,” “device,” and the like may not be a substitute for the word “means.” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for.”
The following examples are illustrative only and may be combined with aspects of other embodiments or teachings described herein, without limitation.
Aspect 1 is an apparatus for wireless communication including at least one processor coupled to a memory and configured to receive, from a second UE, a first reservation of a SL resource for a first SL transmission; receive, from a third UE, a second reservation of the SL resource for a second SL transmission within a threshold amount of time following the reception of the first reservation; and transmit a collision indication based on a collision parameter, where the collision parameter is based on receiving the second reservation within the threshold amount of time following the reception of the first reservation.
Aspect 2 is the apparatus of aspect 1, where the collision parameter includes a relative power threshold range from a plurality of relative power threshold ranges for reservations of a same SL resource, the relative power threshold range is associated with the reception of the first reservation and the reception of the second reservation being within the threshold amount of time, and the collision indication includes an expected conflict indication based on a relative power between the received first reservation and the received second reservation being within the relative power threshold range.
Aspect 3 is the apparatus of aspect 2, where the threshold amount of time is within a range of times associated with the relative power threshold range.
Aspect 4 is the apparatus of any of aspects 2 or 3, where each relative power threshold range in the plurality of relative power threshold ranges is associated with a distinct range of times between different reservations for a same SL resource.
Aspect 5 is the apparatus of aspect 4, where the relative power threshold range is associated with a first range of times including the threshold amount of time and includes a larger range of relative powers than another relative power threshold range associated with a second range of times that are greater than the times included in the first range of times.
Aspect 6 is the apparatus of any of aspects 2 to 5, where each relative power threshold range in the plurality of relative power threshold ranges is determined based on at least one of an ability to decode data on the reserved SL resource, an ability to decode a first type of SCI, or an ability to decode a second type of SCI.
Aspect 7 is the apparatus of aspect 1, where the collision parameter includes a relative power threshold associated with the reception of the first reservation and the reception of the second reservation being within the threshold amount of time, and the collision indication includes an expected conflict indication based on a relative power between the received first reservation and the received second reservation being less than relative power threshold.
Aspect 8 is the apparatus of aspect 7, where the relative power threshold is one of a first relative power threshold associated with different reservations for a same time-and-frequency SL resource or a second relative power threshold associated with different reservations for different SL frequency resources that overlap in time.
Aspect 9 is the apparatus of any of aspects 1 to 8, where transmitting the collision indication includes transmitting the collision indication to the second UE.
Aspect 10 is the apparatus of aspect 9, where the collision indication is transmitted to the second UE based on a priority associated with the second SL transmission.
Aspect 11 is the apparatus of any of aspects 9 or 10, the at least one processor further configured to receive an indication of a collision indication reception capability of the second UE.
Aspect 12 is the apparatus of aspect 11, where the indication of the collision indication reception capability of the second UE is received via a reserved bit in SCI.
Aspect 13 is the apparatus of any of aspects 1 to 12, the at least one processor further configured to receive, from a fourth UE, a third reservation of an additional SL resource for a third SL transmission; receive, from a fifth UE, a fourth reservation of the additional SL resource for a fourth SL transmission within a particular time before the additional SL resource; and skip transmission of a collision indication based on a collision of the third reservation and the fourth reservation based on an occurrence of a condition for not transmitting a collision indication.
Aspect 14 is the apparatus of aspect 13, where the condition for not transmitting a collision indication is at least one of (1) a distance to at least one of the third UE or the fourth UE being below a threshold distance, (2) a measured power of at least one of the third reservation and the fourth reservation being within a range of powers indicating that a collision indication may interfere with sidelink feedback, or (3) both the third reservation and the fourth reservation being for a transmission having been transmitted at least a threshold number of times.
Aspect 15 is the apparatus of aspect 14, where the distance between the third UE or the fourth UE is based on at least one of (1) zone information associated with the first UE and at least one of the third UE or the fourth UE or (2) location information associated with the first UE and at least one of the third UE or the fourth UE.
Aspect 16 is the apparatus of any of aspects 1 to 15, where the collision indication is an expected conflict indication, and the apparatus transmits the expected conflict indication in a first slot having expected conflict indication resources of a resource pool and being at least a minimum time gap after a last slot in which a colliding reservation is received.
Aspect 17 is the apparatus of aspect 16, where a periodicity of the expected conflict indication resource is a same periodicity as a feedback resource periodicity.
Aspect 18 is the apparatus of aspect 16, where a periodicity of the expected conflict indication resource is different from a periodicity of a feedback resource periodicity.
Aspect 19 is the apparatus of any of aspects 16 to 18, where a minimum time gap for an expected conflict indication is less than a minimum time gap for feedback.
Aspect 20 is the apparatus of aspect 19, where the expected conflict indication resource following the received reservation for the SL resource by at least the minimum time gap precedes a SL feedback resource following the reservation for the SL resource by at least the minimum time gap for feedback.
Aspect 21 is the apparatus of any of aspects 16 to 20, where the minimum time gap for an expected conflict indication is less than one slot.
Aspect 22 is the apparatus of any of aspects 1 to 21, further including at least one transceiver coupled to the at least one processor.
Aspect 23 is an apparatus for wireless communication including at least one processor coupled to a memory and configured to transmit a SL reservation for a SL resource, transmit an indication of a capability to receive an expected conflict indication, and receive, based on the transmitted SL reservation and the indication of the capability to receive an expected conflict indication, an expected conflict indication from a first UE.
Aspect 24 is the apparatus of aspect 23, where the indication indicating the capability to receive an expected conflict indication includes at least one bit in a SCI message.
Aspect 25 is the apparatus of aspect 24, where the at least one bit indicating the capability to receive an expected conflict indication includes a reserved bit in the SCI message.
Aspect 26 is the apparatus of any of aspects 24 or 25, where the SL reservation is comprised in the SCI message.
Aspect 27 is the apparatus of any of aspects 23 to 26, further including at least one transceiver coupled to the at least one processor.
Aspect 28 is a method of wireless communication for implementing any of aspects 1 to 27.
Aspect 29 is an apparatus for wireless communication including means for implementing any of aspects 1 to 27.
Aspect 30 is a computer-readable medium storing computer executable code, where the code when executed by a processor causes the processor to implement any of aspects 1 to 27.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2021/109152 | 7/29/2021 | WO |
