Cyclic shift selection for physical sidelink control channel transmissions

Abstract

The invention relates to cyclic shift selection for physical sidelink control channel transmissions. A method, which may be performed by a first user equipment (UE), includes monitoring one or more sidelink control information (SCI) transmissions from one or more second UEs. The method generally includes determining, based on the one or more SCIs, whether one or more conflicts occur between one or more retransmissions of the one or more SCI transmissions by the one or more second UEs and SCI transmissions scheduled by the first UE. The method generally includes selecting a cyclic shift to be used for SCI transmissions scheduled by the first UE based at least in part on the determination.

Description

[0001] This application is a divisional application of the patent application filed on August 20, 2021, with application number 202180068997.2, international application number PCT / US2021 / 046953, and entitled "Cyclic Shift Selection for Physical Side Link Control Channel Transmission". Technical Field

[0002] Various aspects of this disclosure generally relate to wireless communications, and more particularly to techniques for cyclic shift selection for transmission of physical side link control channels. Background Technology

[0003] Wireless communication systems are widely deployed to provide a variety of telecommunications services such as telephone, video, data, messaging, and broadcasting. These wireless communication systems can employ multiple access technologies that enable communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access systems include 3GPP Long Term Evolution (LTE) systems, LTE-A Advanced systems, 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, to name just a few.

[0004] These multiple access technologies have been adopted in various telecommunications standards to provide a common protocol enabling different wireless devices to communicate at the city, country, region, and even global levels. New radios (e.g., 5G NR) are examples of emerging telecommunications standards. NR is an enhancement set of the LTE mobile standard issued by 3GPP. NR is designed to better support mobile broadband Internet access by using OFDMA with a cyclic prefix (CP) on both the downlink (DL) and uplink (UL) to improve spectrum efficiency, reduce costs, improve service, utilize new spectrum, and better integrate with other open standards. To this end, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0005] However, with the continued growth in demand for mobile broadband access, there is a need for further improvements to NR and LTE technologies. Preferably, these improvements should be applicable to other multiple access technologies and telecommunications standards that employ these technologies. Summary of the Invention

[0006] The systems, methods, and apparatuses of this disclosure each have several aspects, and their desired properties are not solely the responsibility of any single aspect. Without limiting the scope of this disclosure as set forth in the appended claims, some features will now be briefly discussed. Upon consideration of this discussion, and especially after reading the section entitled “Detailed Description,” it will be understood how the features of this disclosure provide advantages including improved cyclic shift selection for Physical Side Link Control Channel (PSCCH) retransmissions.

[0007] Certain aspects of the subject matter described in this disclosure can be implemented in a method for wireless communication by a first user equipment (UE). The method generally includes: monitoring one or more sidelink control information (SCI) transmissions from one or more second UEs. The method generally includes: determining, based on one or more SCIs, whether one or more conflicts occur between one or more retransmissions of one or more SCI transmissions performed by one or more second UEs and SCI transmissions scheduled by the first UE. The method generally includes: selecting a cyclic shift to be used for SCI transmissions scheduled by the first UE, at least in part based on the determination.

[0008] Certain aspects of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication. The apparatus generally includes at least one processor and a memory coupled to the at least one processor. The memory generally includes code executable by the at least one processor to cause the apparatus to: monitor one or more SCI transmissions from one or more UEs. The memory generally includes code executable by the at least one processor to cause the apparatus to: determine, based on one or more SCIs, whether one or more conflicts have occurred between one or more retransmissions of one or more SCI transmissions performed by one or more UEs and SCI transmissions scheduled by the apparatus. The memory generally includes code executable by the at least one processor to cause the apparatus to: select a cyclic shift to be used for SCI transmissions scheduled by the apparatus, at least in part based on the determination.

[0009] Certain aspects of the subject matter described in this disclosure can be implemented in a device for wireless communication. The device generally includes: means for monitoring one or more SCI transmissions from one or more UEs. The device generally includes: means for determining, based on one or more SCIs, whether one or more conflicts occur between one or more retransmissions of one or more SCI transmissions performed by one or more UEs and SCI transmissions scheduled by the device. The device generally includes: means for selecting a cyclic shift to be used for SCI transmissions scheduled by the device, at least in part based on the determination.

[0010] Certain aspects of the subject matter described in this disclosure can be implemented in a computer-readable medium having computer-executable code stored thereon for wireless communication by a first UE. The computer-readable medium generally includes code for monitoring one or more SCI transmissions from one or more second UEs. The computer-readable medium generally includes code for determining, based on one or more SCIs, whether one or more conflicts have occurred between one or more retransmissions of one or more SCI transmissions performed by one or more second UEs and SCI transmissions scheduled by the first UE. The computer-readable medium generally includes code for selecting a cyclic shift to be used for SCI transmissions scheduled by the first UE, at least in part based on this determination.

[0011] To achieve the foregoing and related objectives, these one or more aspects include the features fully described below and specifically pointed out in the claims. Certain illustrative features of these one or more aspects are set forth in detail in the following description and drawings. However, these features indicate only a few of the various ways in which the principles of these aspects may be employed. Attached Figure Description

[0012] To gain a more detailed understanding of the manner in which the features described above are presented in this disclosure, reference can be made to various aspects of the above brief overview, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only certain typical aspects of this disclosure and should not be considered as limiting its scope, as other equivalent aspects are permissible in this description.

[0013] Figure 1 It is a block diagram that conceptually illustrates certain aspects of an example telecommunications system according to this disclosure.

[0014] Figure 2 It is a block diagram that conceptually illustrates the design of an example base station (BS) and user equipment (UE) according to certain aspects of this disclosure.

[0015] Figure 3 This is an example frame format for New Radio (NR) based on certain aspects of this disclosure.

[0016] Figure 4 An example vehicle-to-everything (V2X) communication system based on certain aspects of this disclosure is described.

[0017] Figure 5 Another example V2X communication system according to certain aspects of this disclosure is described.

[0018] Figure 6A and 6B An example of a hidden UE scene is shown in accordance with certain aspects of this disclosure.

[0019] Figure 7AExample resources are described in accordance with certain aspects of this disclosure when assigning resource blocks in cellular V2X (C-V2X) direct communication with packet collisions.

[0020] Figure 7B Example resources are described in accordance with certain aspects of this disclosure when assigning resource blocks in C-V2X direct communication with overlapping packets.

[0021] Figure 8 This is a parameter table for sidelink transmission in a C-V2X system, based on certain aspects of this disclosure.

[0022] Figure 9 Example side link control information (SCI) transmission and retransmission according to certain aspects of this disclosure are explained.

[0023] Figure 10 This is a call flow diagram illustrating example signaling for cyclic shift selection for retransmission of the Physical Side Link Control Channel (PSCCH) according to various aspects of this disclosure.

[0024] Figure 11 This is a flowchart illustrating example operations for wireless communication by a UE according to certain aspects of this disclosure.

[0025] Figure 12 The description of various aspects of this disclosure includes communication devices that may include various components configured to perform operations for the various techniques disclosed herein.

[0026] To facilitate understanding, the same reference numerals are used wherever possible to designate common elements shared by all figures. Elements disclosed in one aspect are conceived to be usefully applied in other aspects without specific citation. Detailed Implementation

[0027] This disclosure provides apparatus, methods, processing systems, and computer-readable media for cyclic shift selection of physical side link control channel (PSCCH) retransmissions, such as in cellular vehicle-to-everything (C-V2X) direct communication.

[0028] In C-V2X systems, user equipment (UEs) (such as vehicle UEs) can communicate directly with each other using time-frequency resources autonomously selected by the UE. However, when two UEs select the same resources, autonomous resource selection can cause problems, leading to packet collisions or packet overlaps. For example, in some scenarios, a UE may be "hidden" during channel eavesdropping and initial resource selection (e.g., autonomous semi-persistent scheduling (SPS) resource selection) and may be experiencing interference.

[0029] This disclosure provides techniques for selecting cyclic shifts for PSCCH retransmissions. In some examples, the UE monitors the sidelink control information (SCI) and corresponding SCI transmissions of other UEs, as well as any conflicts between its own transmissions (and retransmissions) and those from other UEs. The UE can select a cyclic shift for its own SCI transmissions (initial SCI transmission or SCI retransmission) based on the presence or absence of a conflict.

[0030] The following description provides examples of cyclic shift selection for PSCCH retransmission in a communication system and is not intended to limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the elements discussed without departing from the scope of this disclosure. Various procedures or components may be appropriately omitted, substituted, or added to various examples. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Moreover, features described with reference to some examples may be combined in others. For example, any number of aspects set forth herein may be used to implement an apparatus or practice. Furthermore, the scope of this disclosure is intended to cover such apparatuses or methods practiced using additional structures, functionalities, or structures and functionalities that complement or supplement the various aspects of this disclosure set forth herein. It should be understood that any aspect of this disclosure disclosed herein may be implemented by one or more elements of the claims. The term “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 superior to or overriding other aspects.

[0031] Generally, any number of wireless networks can be deployed in a given geographical area. Each wireless network can support a specific Radio Access Technology (RAT) and can operate on one or more frequencies. A RAT may also be referred to as a radio technology, air interface, etc. A frequency may also be referred to as a carrier, subcarrier, frequency channel, frequency modulation, subband, etc. Each frequency can support a single RAT in a given geographical area to avoid interference between wireless networks using different RATs.

[0032] The techniques described herein can be used in a variety of wireless network and radio technologies. While the aspects may be described herein using terms commonly associated with 3G, 4G and / or newer radio technologies (e.g., 5G NR), the aspects of this disclosure can be applied to communication systems based on other generations.

[0033] NR access supports a variety of wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., 80 MHz or above), millimeter wave (mmW) targeting high carrier frequencies (e.g., 25 GHz or above), massive machine-type communication (mMTC) targeting non-backward-compatible MTC technology, and / or mission-critical services targeting ultra-reliable low latency communication (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTI) to meet corresponding quality of service (QoS) requirements. Furthermore, these services can coexist in the same subframe. NR supports beamforming, and beam direction can be dynamically configured. Precoded MIMO transmission can also be supported. MIMO configurations in DL can support up to 8 transmit antennas (multilayer DL transmission with up to 8 streams) and up to 2 streams per UE. Multilayer transmission with up to 2 streams per UE can be supported. Up to 8 serving cells can be used to support the aggregation of multiple cells.

[0034] Figure 1 An example wireless communication network 100 in which various aspects of this disclosure can be implemented is described. For example, the wireless communication network 100 may be an NR system (e.g., a 5G NR network). Figure 1 As shown, the wireless communication network 100 can communicate with the core network 132. The core network 132 can communicate with one or more base stations (BS) 110 and / or user equipment (UE) 120 in the wireless communication network 100 via one or more interfaces.

[0035] like Figure 1 As shown, the wireless communication network 100 can communicate with the core network 132. The core network 132 can communicate with one or more base stations (BS) 110a-z (each individually referred to herein as BS 110 or collectively as BS 110) and / or user equipment (UE) 120a-y (each individually referred to herein as UE 120 or collectively as UE 120) in the wireless communication network 100 via one or more interfaces.

[0036] BS 110 can provide communication coverage for a specific geographic area (sometimes referred to as a "cell"), which can be stationary or mobile depending on the location of the mobile BS 110. In some examples, BS 110 can interconnect with each other and / or interconnect to one or more other BSs or network nodes (not shown) in the wireless communication network 100 using any suitable transport network through various types of backhaul interfaces (e.g., direct physical connection, wireless connection, virtual network, etc.). Figure 1In the example shown, BS 110a, 110b, and 110c can be macro BSs for macro cells 102a, 102b, and 102c, respectively. BS 110x can be a pico BS for pico cell 102x. BS 110y and 110z can be femto BSs for femto cells 102y and 102z, respectively. A BS can support one or more cells. Network controller 130 can be coupled to a set of BS 110 and provide coordination and control (e.g., via backhaul) of these BS 110.

[0037] BS 110 communicates with UEs 120a-y (each individually referred to herein as UE 120 or collectively as UE 120) in the wireless communication network 100. UEs 120 (e.g., 120x, 120y, etc.) may be distributed throughout the wireless communication network 100, and each UE 120 may be stationary or mobile. The wireless communication network 100 may also include relay stations (e.g., relay station 110r) (also referred to as relays, etc.) that receive transmissions of data and / or other information from upstream stations (e.g., BS 110a or UE 120r) and transmit such transmissions of data and / or other information to downstream stations (e.g., UE 120 or BS 110), or that relay transmissions between the UEs 120 to facilitate communication between the devices.

[0038] Depending on certain aspects, UE 120 can be configured for cyclic shift selection for retransmissions of the Physical Side Link Control Channel (PSCCH). For example... Figure 1 As shown, UE 120a includes a sidelink manager 122. According to various aspects of this disclosure, the sidelink manager 122 may be configured to monitor one or more sidelink control information (SCI) transmissions from one or more second UEs; determine, based on one or more SCIs, whether one or more conflicts occur between one or more retransmissions of one or more SCI transmissions performed by one or more second UEs and SCI transmissions scheduled by a first UE; and select a cyclic shift to be used for SCI transmissions scheduled by the first UE, based at least in part on the determination.

[0039] Figure 2 The BS 110a and UE 120a, which can be used to implement various aspects of this disclosure, are explained (e.g., in...). Figure 1 Example components in a wireless communication network 100.

[0040] At BS 110a, the transmit processor 220 can receive data from the data source 212 and control information from the controller / processor 240. This control information can be for the Physical Broadcast Channel (PBCH), Physical Control Format Indicator Channel (PCFICH), Physical Hybrid ARQ Indicator Channel (PHICH), Physical Downlink Control Channel (PDCCH), Group Shared PDCCH (GC PDCCH), etc. This data can be for the Physical Downlink Shared Channel (PDSCH), etc. The Media Access Control (MAC)-Control Element (MAC-CE) is a MAC layer communication structure that can be used for exchanging control commands between wireless nodes. The MAC-CE can be carried in shared channels, such as the Physical Downlink Shared Channel (PDSCH), Physical Uplink Shared Channel (PUSCH), or Physical Sidelink Shared Channel (PSSCH).

[0041] Processor 220 can process (e.g., encode and map symbol) data and control information to obtain data symbols and control symbols, respectively. Transmit processor 220 can also generate reference symbols (such as those for primary synchronization signal (PSS), secondary synchronization signal (SSS), and channel state information reference signal (CSI-RS)). Transmit (TX) multiple-input multiple-output (MIMO) processor 230 can perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, and / or reference symbols where applicable, and can provide the output symbol stream to modulators (MODs) 232a-232t in the transceiver. Each modulator in transceivers 232a-232t can process its own output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator can further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. Downlink signals from the modulators in transceivers 232a-232t can be transmitted via antennas 234a-234t respectively.

[0042] At UE 120a, antennas 252a-252r can receive downlink signals from BS 110a and can provide the received signals to demodulators (DEMODs) 254a-254r in the transceiver. Each demodulator 254a-254r in the transceiver can condition (e.g., filter, amplify, down-convert, and digitize) its respective received signal to obtain an input sample. Each demodulator can further process the input sample (e.g., for OFDM, etc.) to obtain received symbols. MIMO detector 256 can obtain the received symbols from all demodulators 254a-254r in the transceiver, perform MIMO detection on these received symbols where applicable, and provide detected symbols. Receiver processor 258 can process (e.g., demodulate, deinterleave, and decode) these detected symbols, provide the decoded data to UE 120a to data sink 260, and provide the decoded control information to controller / processor 280.

[0043] On the uplink, at UE 120a, transmit processor 264 can receive and process data from data source 262 (e.g., for the Physical Uplink Shared Channel (PUSCH)) and control information from controller / processor 280 (e.g., for the Physical Uplink Control Channel (PUCCH)). Transmit processor 264 can also generate reference symbols for reference signals (e.g., probe reference signals (SRS)). Symbols from transmit processor 264 can be pre-encoded by TX MIMO processor 266 where applicable, further processed by modulators (MODs) 254a-254r in the transceiver (e.g., for SC-FDM, etc.), and transmitted to BS 110a. At BS 110a, uplink signals from UE 120a can be received by antenna 234, processed by modulators in transceivers 232a-232t, detected by MIMO detector 236 where applicable, and further processed by receiver processor 238 to obtain decoded data and control information transmitted by UE 120a. Receiver processor 238 can provide the decoded data to data sink 239 and the decoded control information to controller / processor 240.

[0044] Memory 242 and 282 may store data and program code for BS 110a and UE 120a, respectively. Scheduler 244 may schedule UE for data transmission on downlink and / or uplink.

[0045] The antenna 252, processors 266, 258, 264, and / or controller / processor 280, and / or antenna 234, processors 220, 230, 238 of UE 120a can be used to perform the various techniques and methods described herein. Figure 2As shown, according to the aspects described herein, the controller / processor 280 of UE 120a has a sidelink manager 281 that can be configured for cyclic shift selection for PSCCH retransmission. Although shown at the controller / processor, other components of UE 120a and BS110a may also be used to perform the operations described herein.

[0046] NR can utilize Orthogonal Frequency Division Multiplexing (OFDM) with a cyclic prefix (CP) on both the uplink and downlink. NR supports half-duplex operation using Time Division Duplex (TDD). OFDM and Single-Carrier Frequency Division Multiplexing (SC-FDM) divide the system bandwidth into multiple orthogonal subcarriers, which are often referred to as frequency modulation, frequency slots, etc. Each subcarrier can be modulated with data. Modulation symbols can be transmitted in the frequency domain using OFDM and in the time domain using SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers can depend on the system bandwidth. The minimum resource allocation (called a resource block (RB)) can be 12 consecutive subcarriers. The system bandwidth can also be divided into subbands. For example, a subband can cover multiple RBs. NR supports a base subcarrier spacing (SCS) of 15 kHz and can define other SCSs relative to the base SCS (e.g., 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc.).

[0047] Figure 3 This is a diagram illustrating an example of frame format 300 for NR. The transmission timeline for each of the downlink and uplink can be divided into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 ms) and may be divided into 10 subframes with indices 0 to 9, each subframe being 1 ms long. Each subframe may contain a variable number of time slots (e.g., 1, 2, 4, 8, 16, ... time slots), depending on the SCS. Each time slot may include a variable number of symbol periods (e.g., 7 or 14 symbols), depending on the SCS. An index may be assigned to the symbol periods in each time slot. A mini-time slot (which may be referred to as a sub-time slot structure) refers to a transmission time interval with a duration smaller than a time slot (e.g., 2, 3, or 4 symbols). Each symbol in a time slot may indicate the link direction for data transmission (e.g., DL, UL, or flexible), and the link direction for each subframe can be dynamically switched. The link direction may be based on the time slot format. Each time slot may include DL / UL data and DL / UL control information.

[0048] In NR, synchronization signal blocks (SSBs) are transmitted. In some respects, each SSB can be transmitted in a burst, where each SSB in the burst corresponds to a different beam direction for use in UE-side beam management (e.g., including beam selection and / or beam refinement). An SSB includes a PSS, an SSS, and a two-symbol PBCH. SSBs can be transmitted at fixed time slot locations (such as...). Figure 3 The symbols 0-3 shown are transmitted. The PSS and SSS can be used by the UE for cell search and acquisition. The PSS provides half-frame timing, and the SS provides CP length and frame timing. The PSS and SSS provide cell identity. The PBCH carries basic system information such as downlink system bandwidth, timing information within the radio frame, SS burst set periodicity, system frame number, etc. SSBs can be organized into SS bursts to support beam sweeping. Further system information (such as Residual Minimum System Information (RMSI), System Information Block (SIB), and Other System Information (OSI)) can be transmitted in certain subframes on the Physical Downlink Shared Channel (PDSCH). SSBs can be transmitted up to 64 times, for example, up to 64 different beam directions for millimeter waves. Multiple transmissions of an SSB are called SS burst sets. SSBs within an SS burst set can be transmitted in the same frequency region, while SSBs from different SS burst sets can be transmitted in different frequency regions.

[0049] In some examples, communication between UE 120 and BS 110 is referred to as an access link. The access link can be provided via the Uu interface. Communication between devices can be referred to as a side link.

[0050] In some examples, two or more subordinate entities (e.g., UE 120) may use sidelink signaling to communicate with each other. Real-world applications of such sidelink communication may include public safety, proximity services, UE-to-network relay, vehicle-to-vehicle (V2V) communication, Internet of Things (IoE) communication, IoT communication, mission-critical mesh networks, and / or various other suitable applications. Generally, sidelink signaling can refer to a signal that is relayed from one subordinate entity (e.g., UE 120a) to another subordinate entity (e.g., another UE 120) without relaying the communication through a scheduling entity (e.g., UE 120 or BS 110), even if the scheduling entity may be used for scheduling and / or control purposes. In some examples, sidelink signaling may use licensed spectrum for transmission (unlike wireless LANs, which typically use unlicensed spectrum). An example of sidelink communication is PC5, for example, as used in V2V, LTE, and / or NR.

[0051] Various sidelink channels can be used for sidelink communication, including the Physical Sidelink Discovery Channel (PSDCH), Physical Sidelink Control Channel (PSCCH), Physical Sidelink Shared Channel (PSSCH), and Physical Sidelink Feedback Channel (PSFCH). The PSDCH carries discovery expressions that enable neighboring devices to discover each other. The PSCCH carries control signaling (such as sidelink resource configuration and other parameters for data transmission), while the PSSCH carries data transmission. The PSFCH carries feedback, such as CSI related to sidelink channel quality.

[0052] Figure 4 and Figure 5 A schematic representation of an example vehicle-to-everything (V2X) system according to some aspects of this disclosure is shown. For example, Figure 4 and Figure 5 The vehicles shown can communicate via sidelink channels and can relay sidelink transmissions as described herein.

[0053] Figure 4 and Figure 5 The V2X system provided in China offers two complementary transmission modes. Figure 4 The first transmission mode (also known as mode 4), illustrated as an example, involves direct communication between participants who are adjacent to each other in a local area (e.g., also known as sidelink communication). Figure 5 The second transmission mode (also known as mode 3) shown as an example involves network communication over a network, which may be implemented via a Uu interface (e.g., a wireless communication interface between the radio access network (RAN) and the UE).

[0054] Reference Figure 4 The V2X system 400 (e.g., including vehicle-to-vehicle (V2V) communication) is illustrated using two vehicles 402 and 404. A first transmission mode allows direct communication between different participants in a given geographic location. As illustrated, the vehicles may have a wireless communication link 406 (vehicle-to-pedestrian (V2P)) with an individual (e.g., via a UE) through a PC5 interface. Communication between vehicles 402 and 404 may also occur via PC5 interface 408. Communication from vehicle 402 to other highway components (e.g., highway component 410, such as traffic signals or signs) (vehicle-to-infrastructure (V2I)) may occur similarly via PC5 interface 412. Figure 4Each communication link described in the diagram allows for bidirectional communication between elements, thus each element can be both a sender and receiver of information. The V2X system 400 can be a self-managing system implemented without the assistance of network entities. Self-managing systems enable improved spectrum efficiency, reduced costs, and increased reliability because no network service interruption occurs during handover operations for mobile vehicles. V2X systems can be configured to operate in licensed or unlicensed spectrum, allowing any vehicle equipped with the system to access shared frequencies and share information. This coordinated / shared spectrum operation allows for safe and reliable operation.

[0055] Figure 5 A V2X system 500 is illustrated for communication between vehicles 552 and 554 via network entity 556. These network communications can occur via discrete nodes (such as BSs (e.g., BS 110a)) that send and receive information to and from vehicles 552 and 554 (e.g., relaying information between vehicles 552 and 554). Network communications via vehicle-to-network (V2N) links 558 and 510 can be used for long-range communication between vehicles, such as to inform of a traffic accident at a distance along a road or highway. Other types of communication can be sent to vehicles by wireless nodes, such as traffic flow conditions, road hazard warnings, environmental / weather reports, and service station availability, etc. Such data can be obtained from cloud-based shared services.

[0056] Roadside Units (RSUs) can be utilized. RSUs can be used for V2I communication. In some examples, RSUs can act as forwarding nodes to extend UE coverage. In some examples, RSUs can be located alongside BSs or can be independent. RSUs can be classified in different ways. For example, RSUs can be classified as UE-type RSUs and micro-node B-type RSUs. Micro-NB-type RSUs have similar functionality to macro eNBs / gNBs. Micro-NB-type RSUs can utilize the Uu interface. UE-type RSUs can be used to meet stringent Quality of Service (QoS) requirements by minimizing collisions and improving reliability. UE-type RSUs can use centralized resource allocation mechanisms to allow for efficient resource utilization. Critical information (such as, for example, traffic conditions, weather conditions, congestion statistics, sensor data, etc.) can be broadcast to UEs in the coverage area. Relays can rebroadcast critical information received from some UEs. UE-type RSUs can be reliable synchronization sources.

[0057] As mentioned above, aspects of this disclosure relate to sidelink communication, which may include cellular V2X (C-V2X) communication. C-V2X systems can operate in various modes. An example mode, referred to as Mode 3, can be used when the UE is in an area within coverage. In Mode 3, the network can control the allocation of resources for the sidelink UE. In another example mode for V2X systems (referred to as Mode 4), the sidelink UE can autonomously select resources (e.g., resource blocks (RBs)) for transmission to communicate with each other. For example, the resources may be semi-persistent scheduling (SPS) resources. In some examples, the sidelink UE can autonomously select resources based on an SPS algorithm. The SPS algorithm can be configured, hardcoded, or pre-configured at the UE. For example, the SPS algorithm may be based on an SPS algorithm defined in 3GPP technical standards.

[0058] In some systems, UEs can use a listening mechanism to select resources to transmit on. By listening to available and unavailable resources, UEs can select vacant resources and transmit on them, which can reduce or prevent collisions. Listening may involve power estimation (e.g., Resource Signal Strength Indicator (RSSI) measurement). Power estimation can exclude subframes that were not measured (e.g., due to previous transmissions). Resource selection can exclude resources based on anticipated collisions with transmissions from other UEs. However, hidden UEs may not know each other and therefore cannot exclude each other's resources. Therefore, transmissions performed by these UEs may collide on adjacent UEs.

[0059] In some situations, due to dynamically changing environments, "hidden terminal" scenarios may occur. For example, when a sidelink UE selects a resource for transmission (e.g., in mode 4), some other UEs (e.g., vehicles) may be hidden (e.g., undetected), such as when channel sensing is performed. Therefore, two (or more) UEs may (e.g., autonomously) select the same resource. Hidden terminal scenarios (leading to packet collisions) may occur when UEs have overlapping coverage areas when assigning RBs for transmission.

[0060] Figure 6A The scenario of a hidden terminal is explained. For example, UE A and UE C cannot detect each other's presence because these UEs are outside each other's coverage area. Figure 6A As shown, the physical distance d between UE A and UE C is at least r. a + r c , where r a Let r be the coverage radius of UE A. cLet C be the coverage radius of UE C. UE A is unaware of the existence of UE C (“hidden node”), and similarly, UE C is unaware of the existence of UE A. Because UE A and UE C are unaware of each other, these two UEs can allocate / select the same time-frequency resources (some or all) (e.g., overlapping RBs) for transmission. In this scenario, UEs in the common area (A ∩ C) of UE A and UE C (such as...) Figure 6B As shown, UE B is unable to use the allocated resources to decode data transmitted from UE A or UE C due to packet collisions.

[0061] Collisions and overlaps can be seen in congested environments. As used in this paper, overlap occurs when two or more UEs transmit control channels (e.g., PSCCH) and data channels (e.g., PSSCH) on the same resource, and collision occurs when two or more UEs transmit control channels (PSCCH) on the same resource. Figure 7A The example conflict scenario was explained and Figure 7B The example of overlapping scenarios was explained. During the conflict, such as... Figure 7A As shown, PSCCH transmissions from UE1 and UE2 are transmitted on the same resource. During the overlap, as... Figure 7B As shown, PSCCH and PSSCH transmissions from UE1 and UE2 use the same resources for transmission.

[0062] For both collisions and overlaps, in the case of UE1 and UE2 transmitting PSCCH and PSSCH, other UEs may not detect the PSCCH (e.g., those with sidelink control SCI). Although in Figure 7A and 7B The diagram shows transmissions from two UEs, but the system can involve sidelink transmissions from any number of UEs.

[0063] For PSCCH, bit processing can follow the downlink control information (DCI) without scrambling in the Cyclic Redundancy Check (CRC) append. Scrambling can be done using a constant (e.g., c). init = 510) to initialize. PSCCH can be modulated using Quadrature Phase Shift Keying (QPSK). Layer mapping and precoding can be performed using a single antenna port. SCI can be transmitted in PSCCH and includes payload and uncoded bits. The same SCI can include the same transmitted symbols (e.g., encoded, modulated, mapped symbols). Figure 8This is an example parameter table for the reference signal used for PSSCH transmission (e.g., as defined in Table 9.8-2 of TS 36.211). The reference signal used for PSSCH may not use group jumps or sequence jumps and may use the same orthogonal code. The reference signal used for PSSCH may have a cyclic shift that provides channel separation (e.g., four randomly selected values ​​{0, 3, 6, 9}).

[0064] Information about sidelink transmissions can be obtained from the SCI sent in the PSCCH. For SPS transmissions, each SPS transmission indicates a transmission period (e.g., 20 / 50 / 100 / 200...1000 subframes). In this case, information about the transmission can be determined from the periodicity of the indicated SPS transmission. In another example, hybrid Automatic Repeat Request (HARQ) transmissions may involve binding mechanisms and controls (e.g., 1 / 2 / ...15 subframe intervals). For example, redundant versions (e.g., RV0, RV2) may be associated (e.g., pointing to each other). Therefore, information about one RV can be determined from information about another RV. Figure 9 The example SCI RV pair has been explained.

[0065] In some systems (e.g., in Section 9.8 of TS 36.211), for side-link transmission modes 3 and 4 on the PSCCH, the cyclic shift to be applied is randomly selected from {0, 3, 6, 9} in each PSCCH transmission and retransmission (e.g., according to Section 14.2.1 of TS 36.211). Randomly selecting the cyclic shift can help handle collisions.

[0066] Congestion during transmission (such as collisions due to hidden UE scenarios) can be detrimental to C-V2X communication and may lead to increased contention (e.g., Dedicated Short Range Communication (DSRC)). Congestion during transmission can affect Packet Error Rate (PER) and / or Information Age (IA). To address these collisions and overlaps, contention control, silencing, and other techniques have been developed to mitigate the effects of congestion (e.g., increasing Inter-Transmission Time (ITT) by reducing PER and IA).

[0067] Due to the random nature of cyclic shift selection, a UE may receive conflicting PSCCH transmissions with the same cyclic shift. This conflict can lead to the UE misdetecting (i.e., not detecting) a PSCCH. Therefore, in some situations, when the UE autonomously selects resources, it will not exclude resources (e.g., subchannels) from which undetected PSCCH transmissions are received. Consequently, the effectiveness of congestion control is reduced. Conflicts can also cause secondary link management measurements (e.g., synchronization time offset) to be missed. In some cases, due to misdetection of the PSCCH, the UE may misdetect a PSSCH transmission because sidelink control information points to the corresponding sidelink data transmission.

[0068] Collisions between PSCCH transmissions with the same cyclic shift cause the UE to be unable to distinguish between PSCCH transmissions. A UE without prior knowledge can simply decode the strongest PSCCH and unnecessarily lose the PSCCH transmission with a weaker transmission strength (and associated PSSCH) that RV0 passes through its cyclic redundancy check (CRC).

[0069] Accordingly, what is needed is a technology and apparatus for cyclic shift selection of PSCCH transmission and retransmission in sidelink communication.

[0070] Example Cyclic Shift Selection for Physical Side Link Control Channel Transmission

[0071] This disclosure provides cyclic shift selection for Physical Sidelink Control Channel (PSCCH) transmissions and retransmissions (such as in cellular vehicle-to-everything (C-V2X) communications). In some aspects, a first User Equipment (UE) monitors Sidelink Control Indicator (SCI) transmissions from a second UE. The SCI transmission from the second UE may conflict with one of the SCI transmissions from the first UE (either an initial transmission or a retransmission). Based on the presence or absence of a transmission conflict, the first UE selects a cyclic shift to use for its transmission. The selection of the cyclic shift may depend on the presence of a transmission and whether that transmission is an initial transmission or a retransmission from either the first or second UE.

[0072] Various aspects of this disclosure are intended to prevent multiple UEs from selecting the same cyclic shift over overlapping transmissions. Certain aspects of this disclosure provide criteria for selecting the cyclic shift used for PSCCH retransmission.

[0073] Depending on certain aspects, the UE may transmit PSCCH retransmissions on resources where no known conflicts exist (e.g., redundant version, RV2). When no known conflicts exist, the UE may select the same cyclic shift (e.g., RV0) as the one randomly selected for the initial PSCCH transmission for PSCCH retransmission. In some examples, the cyclic shift is randomly selected from a set of cyclic shifts such as {0, 3, 6, 9}. When the cyclic shift is used for retransmission, this cyclic shift CS... x It can be removed from the unused circular shift set.

[0074] In some respects, a UE may transmit on the same resources used by another UE (at least one other UE) for PSCCH retransmission (e.g., a collision determined by the UE based on the first detection of an SCI from that other UE). When a UE is transmitting an initial PSCCH transmission (e.g., RV0) that conflicts with a PSCCH retransmission from that other UE, the UE may randomly select a cyclic shift from an unused cyclic shift group (e.g., a set) for its initial PSCCH transmission. This unused cyclic shift group may include a list of available cyclic shifts (e.g., {0, 3, 6, 9}) that exclude cyclic shifts used by other UEs to transmit their PSCCH retransmissions. For example, if another UE uses cyclic shift 3 to transmit its PSCCH retransmission, the UE may randomly select a cyclic shift from the remaining unused cyclic shift set {0, 6, 9} for its initial PSCCH transmission.

[0075] Figure 10 This describes a call flow of example signaling 1000 between UE1 and UE2 according to certain aspects of this disclosure. At 1002, UE1 may send an RV0 PSCCH transmission to UE2, which provides SCI and information about the Physical Side Link Shared Channel (PSSCH) RV0 transmission. At 1004, UE1 receives the RV0 PSCCH transmission from UE2. After receiving the PSCCH RV0 from UE2 at 1004, then at 1008, UE1 may update the unused cyclic shift group to exclude the cyclic shift used by UE2 to transmit UE2's PSCCH transmission (at 1004).

[0076] At 1006, UE1 can detect collisions based on the SCI received from UE2 (at 1004). For example, the SCI from UE2 may point to a retransmission of the SCI on the PSCCH at 1012b. UE1 can detect that UE1 has a conflicting PSCCH transmission or retransmission at 1012a.

[0077] According to certain aspects, in 1010, UE1 may select the cyclic shift for its conflicting PSCCH transmission in 1012a based on this determination.

[0078] In some aspects, in UE (e.g., Figure 10 In the case where UE1 is sending a PSCCH retransmission (e.g., RV2 in 1012a) that conflicts with another UE's PSCCH retransmission (e.g., RV2 in 1012b), the cyclic shift selected by that UE may depend on whether the cyclic shift of the corresponding initial PSCCH transmission for that UE (e.g., RV0 at 1002) is included in the unused cyclic shift group.

[0079] If the cyclic shift used for the initial PSCCH transmission (e.g., in 1002) is included in an unused cyclic shift group, the UE may (e.g., in 1010) select the same cyclic shift for PSCCH retransmission (e.g., in 1012a). That is, if the cyclic shift used for the UE's initial transmission differs from the cyclic shift used for any conflicting PSCCH retransmission by another UE, the cyclic shift used for the UE's initial transmission can be reused for the corresponding retransmission. On the other hand, if the cyclic shift used for the UE's initial PSCCH transmission is not included in an unused cyclic shift group, the UE may randomly select a cyclic shift from that unused cyclic shift group for its retransmission. That is, if the cyclic shift used for the initial transmission performed by the UE is the same as the cyclic shift used for any conflicting PSCCH retransmission by another UE, the cyclic shift used for the initial transmission performed by the UE cannot be reused for the corresponding retransmission. In some respects, if the cyclic shift used for the initial PSCCH transmission by the UE is not included in the unused cyclic shift group, the UE may select the same cyclic shift used for the initial transmission by the UE for its retransmission, and this cyclic shift is randomly selected. In other words, when a conflict exists, the UE may randomly select from the unused CS or select the same CS used for RV0 transmission.

[0080] In some respects, the cyclic shift selection method described above can be activated or deactivated. For example, when congestion is observed (i.e., as a congestion control mechanism), such as when congestion reaches a defined threshold, the UE can perform the above-described cyclic shift selection for PSCCH retransmission.

[0081] Various aspects of this disclosure can be detected during the transmission of HARQ pairs (RV0 and RV2 pairs). In some examples, the UE can transmit RV0 and RV2 consecutively, and correspondingly, most RV0 and RV2 transmissions can have the same cyclic shift. Through the random selection of the cyclic shift, the transmission has a collision probability of approximately 25%.

[0082] The aspects of this disclosure can be detected when RV0 is transmitted on resources having overlapping RV2s. For example, a first UE supporting the same cyclic shift transmission can continuously transmit HARQ pairs (with the same cyclic shift), and a second UE can continuously transmit RV0s that conflict with RV2. Accordingly, the aspects of this disclosure can avoid using the same cyclic shift for the initial PSCCH transmission, and instead, through purely random selection of cyclic shifts, the cyclic shifts will be evenly distributed.

[0083] Figure 11 This is a flowchart illustrating an example operation 1100 for wireless communication according to certain aspects of this disclosure. Operation 1100 may be performed, for example, by a first UE (e.g., UE 120a in wireless communication network 100). Operation 1100 may be implemented in one or more processors (e.g., Figure 2 The software components executed and running on the controller / processor 280. Furthermore, the signal transmission and reception performed by the UE in operation 1000 may be, for example, by one or more antennas (e.g., Figure 2 This can be achieved via antenna 252. In some respects, signal transmission and / or reception by the UE can be achieved by obtaining and / or outputting signals via a bus interface of one or more processors (e.g., controller / processor 280).

[0084] Operation 1100 may begin at 1105 by monitoring one or more SCI transmissions from one or more second UEs. For example, the first UE may monitor one or more PSCCHs to look for SCIs from one or more sidelink UEs.

[0085] At 1110, the first UE determines, based on one or more SCIs, whether one or more retransmissions of one or more SCI transmissions performed by one or more second UEs occur between the first UE and the SCI transmissions scheduled by the first UE. Determining whether one or more conflicts occur may involve the first UE determining, based on the SCI transmissions from one or more second UEs, the time and frequency resources used for the one or more retransmissions of the one or more SCI transmissions performed by one or more second UEs. The first UE may determine a conflict occurs when the same time and frequency resources used for the one or more retransmissions of the one or more SCI transmissions performed by one or more second UEs are used (e.g., scheduled for, allocated for, or indicated for) the SCI transmissions scheduled by the first UE. When the SCI transmissions scheduled by the first UE use different time and frequency resources than the one or more retransmissions performed by one or more second UEs, the first UE may determine that no conflict has occurred.

[0086] At 1115, the first UE selects the cyclic shift to be used for the SCI transmission scheduled by the first UE, at least in part, based on this determination.

[0087] According to some aspects, when the first UE determines that no conflict has occurred, the selection of the cyclic shift to be used for the SCI transmission scheduled by the first UE involves randomly selecting a cyclic shift from a set of multiple cyclic shifts used for the initial transmission of the first UE, and selecting the cyclic shift randomly selected for the initial transmission for the retransmission of the first UE.

[0088] According to some aspects, when the first UE determines that a conflict has occurred, the first UE determines one or more cyclic shifts for one or more retransmissions of one or more SCI transmissions performed by one or more second UEs based on one or more cyclic shifts for one or more SCI transmissions performed by one or more second UEs.

[0089] In some aspects, selecting a cyclic shift to be used for an SCI transmission scheduled by the first UE includes: when the scheduled transmission is the initial transmission, randomly selecting a cyclic shift from a set of multiple cyclic shifts, the set of multiple cyclic shifts excluding determined cyclic shifts for one or more retransmissions of one or more SCI transmissions performed by one or more second UEs, the one or more retransmissions conflicting with the SCI transmission scheduled by the first UE.

[0090] In some respects, selecting the cyclic shift to be used for an SCI transmission scheduled by the first UE includes: selecting the same cyclic shift for the initial transmission performed by the first UE when the scheduled SCI transmission is a retransmission and the cyclic shift used for the initial transmission is different from the determined cyclic shift used for one or more retransmissions of one or more SCI transmissions performed by one or more second UEs.

[0091] In some aspects, selecting the cyclic shift to be used for an SCI transmission scheduled by the first UE includes: when the scheduled SCI transmission is a retransmission and the cyclic shift used for the initial transmission is the same as at least one of a determined cyclic shift for one or more retransmissions of one or more SCI transmissions performed by one or more second UEs, randomly selecting a cyclic shift from a set of multiple cyclic shifts, the set of multiple cyclic shifts excluding the determined cyclic shifts for one or more retransmissions of one or more SCI transmissions performed by one or more second UEs that conflict with the SCI transmission scheduled by the first UE.

[0092] In some respects, when the scheduled SCI transmission is a retransmission and the cyclic shift used for the initial transmission is the same as at least one of the determined cyclic shifts for one or more retransmissions of one or more SCI transmissions performed by one or more second UEs, selecting the cyclic shift to be used for the SCI transmission scheduled by the first UE includes: selecting the same cyclic shift for the initial transmission performed by the first UE, or randomly selecting a cyclic shift from a set of multiple cyclic shifts that excludes one or more determined cyclic shifts for one or more retransmissions of one or more SCI transmissions performed by one or more second UEs that conflict with the SCI transmission scheduled by the first UE.

[0093] In some respects, selecting the cyclic shift to be used for SCI transmissions scheduled by the first UE includes: determining the technique for selecting the cyclic shift based on whether the detected congestion level is at or above a congestion threshold level.

[0094] In some respects, transmissions performed by the first UE or the second UE are associated with a first redundancy version (RV0), and retransmissions performed by the first UE or the second UE corresponding to the first SCI transmission are associated with a second redundancy version (RV2).

[0095] In some respects, the first UE and one or more second UEs are configured for C-V2X communication, and the first UE monitors one or more SCI transmissions from one or more second UEs in the Physical Side Link Control Channel (PSCCH) of a subframe. In other respects, the first UE and one or more second UEs are configured to use transmission mode 4 for C-V2X communication, and the first UE and one or more second UEs autonomously select transmission resources.

[0096] Figure 12 The description may include operations that are configured to perform the techniques disclosed herein (such as...). Figure 11 The communication device 1200 comprises various components (e.g., corresponding to device plus functional components) of the operation described herein. The communication device 1200 includes a processing system 1202 coupled to a transceiver 1208 (e.g., a transmitter and / or receiver). The transceiver 1208 is configured to transmit and receive signals (such as the various signals described herein) for the communication device 1200 via an antenna 1210. The processing system 1202 may be configured to perform processing functions for the communication device 1200, including processing signals received and / or to be transmitted by the communication device 1200.

[0097] Processing system 1202 includes processor 1204 coupled to computer-readable medium / memory 1212 via bus 1206. In some aspects, computer-readable medium / memory 1212 is configured to store instructions (e.g., computer-executable code) that, when executed by processor 1204, cause processor 1204 to perform... Figure 11 The operations described herein or other operations used to perform the various techniques discussed herein for cyclic shift selection for PSCCH transmissions. In some aspects, according to aspects of this disclosure, computer-readable medium / memory 1212 stores code 1214 for monitoring one or more SCI transmissions from one or more UEs; code 1216 for determining, based on one or more SCIs, whether one or more retransmissions of one or more SCI transmissions performed by one or more second UEs conflict with an SCI transmission scheduled by a first UE; and code 1218 for selecting a cyclic shift for an SCI transmission scheduled by the first UE, at least in part based on this determination. In some aspects, processor 1204 has a circuitry configured to implement the code stored in computer-readable medium / memory 1212. According to various aspects of this disclosure, processor 1204 includes circuitry 1224 for monitoring one or more SCI transmissions from one or more second UEs; circuitry 1226 for determining, based on one or more SCIs, whether one or more retransmissions of one or more SCI transmissions performed by one or more second UEs have caused one or more conflicts with an SCI transmission scheduled by a first UE; and circuitry 1228 for selecting a cyclic shift to be used for an SCI transmission scheduled by the first UE, based at least in part on the determination.

[0098] Example

[0099] In a first aspect, a method for wireless communication by a first user equipment (UE) includes: monitoring one or more side link control information (SCI) transmissions from one or more second UEs; determining, based on one or more SCIs, whether one or more conflicts occur between one or more retransmissions of one or more SCI transmissions performed by one or more second UEs and SCI transmissions scheduled by the first UE; and selecting a cyclic shift to be used for SCI transmissions scheduled by the first UE, based at least in part on the determination.

[0100] In a second aspect, in conjunction with the first aspect, determining whether one or more conflicts have occurred includes: determining, based on the SCI transmission, the time and frequency resources for one or more retransmissions of one or more SCI transmissions performed by one or more second UEs; and determining the same time and frequency resources for SCI transmissions scheduled by the first UE.

[0101] In a third aspect, in conjunction with either the first or second aspect, determining whether one or more conflicts have occurred includes: determining that no conflict has occurred; and selecting a cyclic shift to be used for an SCI transmission scheduled by the first UE includes randomly selecting a cyclic shift from a set of multiple cyclic shifts for an initial transmission performed by the first UE; and selecting the cyclic shift randomly selected for the initial transmission for a retransmission performed by the first UE.

[0102] In a fourth aspect, in conjunction with any of the first to third aspects, determining whether one or more collisions have occurred includes: determining that one or more collisions have occurred; and the method further includes determining one or more cyclic shifts for one or more retransmissions of one or more SCI transmissions performed by one or more second UEs based on one or more cyclic shifts for one or more SCI transmissions performed by one or more second UEs.

[0103] In the fifth aspect, in conjunction with the fourth aspect, selecting the cyclic shift to be used for an SCI transmission scheduled by the first UE includes: when the scheduled SCI transmission is the initial transmission, randomly selecting a cyclic shift from a set of multiple cyclic shifts, the set of multiple cyclic shifts excluding determined cyclic shifts for one or more retransmissions of one or more SCI transmissions performed by one or more second UEs, the one or more retransmissions conflicting with the SCI transmission scheduled by the first UE.

[0104] In a sixth aspect, in conjunction with either the fourth or fifth aspect, selecting the cyclic shift to be used for an SCI transmission scheduled by the first UE includes: when the scheduled SCI transmission is a retransmission and the cyclic shift used for the initial transmission is different from the determined cyclic shift used for one or more retransmissions of one or more SCI transmissions performed by one or more second UEs, selecting the same cyclic shift used for the initial transmission performed by the first UE.

[0105] In a seventh aspect, in conjunction with any of the fourth to sixth aspects, when the scheduled SCI transmission is a retransmission and the cyclic shift used for the initial transmission is the same as at least one of the determined cyclic shifts for one or more retransmissions of one or more SCI transmissions performed by one or more second UEs, selecting the cyclic shift to be used for the SCI transmission scheduled by the first UE comprises: selecting the same cyclic shift for the initial transmission performed by the first UE, or randomly selecting a cyclic shift from a set of multiple cyclic shifts that excludes the determined cyclic shifts for one or more retransmissions of one or more SCI transmissions performed by one or more second UEs that conflict with the SCI transmission scheduled by the first UE.

[0106] In the eighth aspect, in conjunction with any of the first to seventh aspects, selecting a cyclic shift includes: determining a technique for selecting a cyclic shift based on whether the detected congestion level is at or above a congestion threshold level.

[0107] In the ninth aspect, in conjunction with any of the first to eighth aspects, the transmission is associated with the first redundant version (RV0), and the retransmission corresponding to the first SCI transmission is associated with the second RV (RV2).

[0108] In the tenth aspect, in conjunction with any of the first to ninth aspects, the first UE and one or more second UEs are configured for cellular vehicle-to-everything (C-V2X) communication; and the first UE monitors one or more SCI transmissions from one or more second UEs in the physical side link control channel (PSCCH) of a subframe.

[0109] In the eleventh aspect, in conjunction with any of the first to tenth aspects, the first UE and one or more second UEs are configured to use transmission mode 4 for C-V2X communication, and wherein the first UE and one or more second UEs autonomously select transmission resources.

[0110] The techniques described in this article can be used in a variety of wireless communication technologies, such as NR (e.g., 5G NR), 3GPP Long Term Evolution (LTE), LTE-A Advanced (LTE-A), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), Time Division Synchronous Code Division Multiple Access (TD-SCDMA), and other networks. The terms "network" and "system" are often used interchangeably. CDMA networks can implement radio technologies such as Universal Terrestrial Radio Access (UTRA) and cdma2000. UTRA includes Wideband CDMA (WCDMA) and other CDMA variants. cdma2000 covers the IS-2000, IS-95, and IS-856 standards. TDMA networks can implement radio technologies such as Global System for Mobile Communications (GSM). OFDMA networks can implement radio technologies such as NR (e.g., 5G RA), evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Flash-OFDMA. UTRA and E-UTRA are parts of the Universal Mobile Telecommunications System (UMTS). LTE and LTE-A are UMTS versions using E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization called the 3rd Generation Partnership Project (3GPP). cdma2000 and UMB are described in documents from an organization called the 3rd Generation Partnership Project 2 (3GPP2). NR is an emerging wireless communication technology under development.

[0111] In 3GPP, the term "cell" can refer to the coverage area of ​​a B-node (NB) and / or the NB subsystem serving that coverage area, depending on the context in which the term is used. In NR systems, the terms "cell" and BS, next-generation B-node (gNB or g B-node), access point (AP), distributed cell (DU), carrier, or transmit / receive point (TRP) can be used interchangeably. A BS can provide communication coverage for macrocells, picocells, femtocells, and / or other types of cells. A macrocell can cover a relatively large geographic area (e.g., a radius of several kilometers) and allows unrestricted access by UEs with a service subscription. A picocell can cover a relatively small geographic area and allows unrestricted access by UEs with a service subscription. A femtocell can cover a relatively small geographic area (e.g., a residential area) and allows restricted access by UEs associated with that femtocell (e.g., UEs in a closed subscriber group (CSG), UEs of users in a residential area, etc.). A BS used for a macrocell can be referred to as a macro BS. A BS used for picocells can be called a picoBS. A BS used for femtocells can be called a femtoBS or a home BS.

[0112] A UE can also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, customer premises equipment (CPE), cellular phone, smartphone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, tablet computer, camera, gaming device, netbook, smartbook, ultrabook, appliance, medical device or medical equipment, biometric sensor / device, wearable device (such as smartwatch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet, etc.)), entertainment device (e.g., music device, video device, satellite radio, etc.), vehicle component or sensor, smart meter / sensor, industrial manufacturing equipment, GPS device, or any other suitable device configured to communicate via wireless or wired media. Some UEs may be considered machine-type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., which can communicate with a BS, another device (e.g., a remote device), or another entity. Wireless nodes can provide connectivity to or to a network (e.g., a wide area network, such as the Internet or cellular networks) via wired or wireless communication links, for example. Some UEs can be considered Internet of Things (IoT) devices, which can be narrowband IoT (NB-IoT) devices.

[0113] In some examples, access to the air interface can be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication among some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, the subordinate entity utilizes the resources allocated by the scheduling entity. A base station is not the only entity that can be used as a scheduling entity. In some examples, a UE may act as a scheduling entity and can schedule resources for one or more subordinate entities (e.g., one or more other UEs), and other UEs may utilize the resources scheduled by that UE for wireless communication. In some examples, a UE may act as a scheduling entity in a peer-to-peer (P2P) network and / or in a mesh network. In the mesh network example, UEs may communicate directly with each other in addition to communicating with a scheduling entity.

[0114] The methods disclosed herein include one or more steps or actions for implementing the method. These method steps and / or actions may be interchanged without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions may be modified without departing from the scope of the claims.

[0115] As used in this article, the phrase “at least one of” a list of items refers to any combination of those items, including a single member. As an example, “at least one of a, b, or c” is intended to cover: a, b, c, ab, ac, bc, and abc, as well as any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0116] As used herein, the term "determine" encompasses a wide variety of actions. For example, "determine" can include calculation, computation, processing, derivation, research, searching (e.g., searching in a table, database, or other data structure), ascertaining, and the like. Furthermore, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), and the like. Moreover, "determine" can include parsing, selecting, choosing, building, and the like.

[0117] The preceding description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will readily be understood by those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but are to be granted the full scope consistent with the language of the claims, wherein references to the singular form of an element are not intended to mean “one and only one” (unless specifically stated otherwise) but “one or more.” Unless specifically stated otherwise, the term “some / a” refers to one or more. All structural and functional equivalents of the aspects described throughout this disclosure that are now or hereafter known to a person skilled in the art are expressly incorporated herein by reference and are intended to be covered by the claims. Furthermore, nothing disclosed herein is intended to be donated to the public, whether or not such disclosure is expressly stated in the claims. No element of a claim should be interpreted in accordance with the provisions of 35 USC §112(f) unless the element is expressly stated using the phrase “means for…” or, in the case of a method claim, the element is stated using the phrase “steps for…”.

[0118] The various operations of the methods described above can be performed by any suitable means capable of performing the corresponding functions. These means may include various hardware and / or software components and / or modules, including but not limited to circuits, application-specific integrated circuits (ASICs), or processors. Generally, where the operations illustrated in the figures are present, these operations may have corresponding paired means with similar numbers plus functional components.

[0119] The various illustrative logic blocks, modules, and circuits described in this disclosure can be implemented or executed using a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but in alternatives, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration.

[0120] If implemented in hardware, an example hardware configuration could include a processing system in a wireless node. The processing system can be implemented using a bus architecture. Depending on the specific application and overall design constraints of the processing system, the bus can include any number of interconnect buses and bridges. The bus can link together various circuits, including a processor, machine-readable media, and a bus interface. The bus interface can be used to connect network adapters, etc., to the processing system via the bus. The network adapter can be used to implement signal processing functions at the PHY layer. In the user terminal (see...), Figure 1 In such cases, the user interface (e.g., keypad, display, mouse, joystick, etc.) can also be connected to the bus. The bus can also link various other circuits (such as timing sources, peripherals, voltage regulators, power management circuits, etc.), which are well known in the art and will therefore not be described further. The processor can be implemented using one or more general-purpose and / or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuit systems capable of executing software. Depending on the specific application and the overall design constraints imposed on the system, those skilled in the art will recognize how best to implement the functionality described for the processing system.

[0121] If implemented in software, the functions can be stored or transmitted as one or more instructions or codes on a computer-readable medium. Software should be broadly interpreted to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media includes both computer storage media and communication media, encompassing any medium that facilitates the transfer of a computer program from one location to another. The processor may be responsible for managing the bus and general processing, including executing software modules stored on the machine-readable storage medium. The computer-readable storage medium may be coupled to the processor so that the processor can read and write information to / from the storage medium. Alternatively, the storage medium may be integrated into the processor. As an example, the machine-readable medium may include a transmission line, a data-modulated carrier wave, and / or a separate computer-readable storage medium containing instructions stored thereon, all accessible to the processor via a bus interface. Alternatively or additionally, the machine-readable medium or any portion thereof may be integrated into the processor, such as caches and / or general-purpose register files. As an example, examples of machine-readable storage media may include RAM (random access memory), flash memory, ROM (read-only memory), PROM (programmable read-only memory), EPROM (erasable programmable read-only memory), EEPROM (electrically erasable programmable read-only memory), registers, disks, optical disks, hard drives, or any other suitable storage media, or any combination thereof. Machine-readable media may be implemented in computer program products.

[0122] Software modules may comprise a single instruction or a number of instructions, and may be distributed across several different code segments, across different programs, and across multiple storage media. Computer-readable media may include multiple software modules. These software modules include instructions that, when executed by an instrument (such as a processor), enable the processing system to perform various functions. These software modules may include transfer modules and receive modules. Each software module may reside in a single storage device or be distributed across multiple storage devices. As an example, when a trigger event occurs, a software module may be loaded from a hard drive into RAM. During the execution of a software module, the processor may load some instructions into a cache to improve access speed. One or more cache lines may subsequently be loaded into a general-purpose register file for processor execution. In the context of the functionality of a software module described below, it will be understood that such functionality is implemented by the processor when the processor executes the instructions from that software module.

[0123] Similarly, any connection is also legitimately referred to as a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technology (such as infrared (IR), radio, and microwave), then that coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technology (such as infrared, radio, and microwave) is included in the definition of a medium. As used herein, disk and disc include compact discs (CDs), laser discs, optical discs, digital multi-purpose discs (DVDs), floppy disks, and Blu-ray® discs, where disks often magnetically reproduce data, and discs optically reproduce data using lasers. Therefore, in some aspects, a computer-readable medium may include non-transient computer-readable media (e.g., tangible media). In other aspects, a computer-readable medium may include transient computer-readable media (e.g., signals). Combinations of the above should also be included within the scope of computer-readable media.

[0124] Therefore, certain aspects may include computer program products for performing the operations described herein. For example, such computer program products may include computer-readable media on which instructions are stored (and / or encoded) that can be executed by one or more processors to perform the operations described herein, such as those for performing the operations described herein and in... Figure 11 The instructions for the operation explained in the text.

[0125] Furthermore, it should be understood that modules and / or other suitable means for performing the methods and techniques described herein may be downloaded and / or otherwise obtained by the user terminal and / or base station where applicable. For example, such devices can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage device (e.g., RAM, ROM, physical storage media such as CDs or floppy disks, etc.) so that the device can obtain the various methods once the storage device is coupled to or provided to the user terminal and / or base station. In addition, any other suitable techniques suitable for providing the methods and techniques described herein to the device may be utilized.

[0126] It will be understood that the claims are not limited to the precise configurations and components described above. Various modifications, substitutions, and variations may be made to the layout, operation, and details of the methods and apparatus described above without departing from the scope of the claims.

Claims

1. A method for wireless communication by a first user equipment (UE), comprising: Monitor the transmission of one or more Side Link Control Information (SCI) messages from one or more second UEs; Based on the one or more SCIs, it is determined that interference occurs between one or more retransmissions of the one or more SCI transmissions performed by the one or more second UEs and the scheduled SCI transmissions performed by the first UE; The cyclic shift to be used for the scheduled SCI transmission of the first UE is selected based at least on the determination; The method further includes: One or more cyclic shifts for the one or more retransmissions of the one or more SCI transmissions performed by the one or more second UEs are determined based on one or more cyclic shifts for the one or more SCI transmissions performed by the one or more second UEs.

2. The method of claim 1, wherein determining that a conflict has occurred comprises: The time and frequency resources for the one or more retransmissions of the one or more SCI transmissions performed by the one or more second UEs are determined based on the SCI transmissions. as well as Determine the same time and frequency resources for the scheduled SCI transmissions performed by the first UE.

3. The method of claim 1, wherein selecting the cyclic shift to be used for the scheduled SCI transmission of the first UE comprises: When the scheduled SCI transmission is the initial transmission, a cyclic shift is randomly selected from a set of multiple cyclic shifts, the set of multiple cyclic shifts excluding the determined one or more cyclic shifts used for retransmissions of the one or more SCI transmissions performed by the one or more second UEs that conflict with the scheduled SCI transmission performed by the first UE.

4. The method of claim 1, wherein selecting the cyclic shift to be used for the scheduled SCI transmission of the first UE comprises: When the scheduled SCI transmission is a retransmission and the cyclic shift for the initial transmission performed by the first UE is different from the one or more cyclic shifts determined for the one or more retransmissions of the one or more SCI transmissions performed by the one or more second UEs, the same cyclic shift is selected for the initial transmission.

5. The method of claim 1, wherein when the scheduled SCI transmission is a retransmission and the cyclic shift for the initial transmission is the same as at least one of one or more cyclic shifts determined by the one or more retransmissions for the one or more SCI transmissions performed for the one or more second UEs, selecting the cyclic shift for the scheduled SCI transmission performed by the first UE comprises: Select the same cyclic shift used for the initial transmission performed by the first UE, or A cyclic shift is randomly selected from a set of multiple cyclic shifts, the set of multiple cyclic shifts excluding the determined one or more cyclic shifts used for retransmissions of the one or more SCI transmissions performed by the one or more second UEs that conflict with the scheduled SCI transmission performed by the first UE.

6. The method of claim 1, wherein selecting the cyclic shift comprises: The technique for selecting cyclic shifts is determined based on whether the detected congestion level is at or above a congestion threshold level.

7. The method of claim 1, wherein the transmission is associated with a first redundancy version RV0, and the retransmission corresponding to the first SCI transmission is associated with a second RV RV2.

8. The method of claim 1, wherein: The first UE and the one or more second UEs are configured for cellular vehicle-to-everything (C-V2X) communication; The first UE monitors the one or more SCI transmissions from the one or more second UEs in the physical side link control channel (PSCCH) within a subframe.

9. The method of claim 8, wherein the first UE and the one or more second UEs are configured for transmission mode 4 for C-V2X communication, and wherein the first UE and the one or more second UEs autonomously select transmission resources.

10. An apparatus for wireless communication, comprising: At least one processor; as well as A memory coupled to the at least one processor, the memory including code executable by the at least one processor to cause the device to perform the following operations: Monitor one or more Side Link Control Information (SCI) transmissions from one or more User Equipment (UEs); Based on the one or more SCIs, it is determined that interference occurs between one or more retransmissions of the one or more SCI transmissions performed by the one or more UEs and the scheduled SCI transmissions performed by the device; The cyclic shift to be used for the scheduled SCI transfer performed by the device is selected based at least on the determination; and The code further causes the device to perform the following operation: determine one or more cyclic shifts for one or more retransmissions of the one or more SCI transmissions performed for the one or more UEs based on one or more cyclic shifts for the one or more SCI transmissions performed for the one or more UEs.

11. The apparatus of claim 10, wherein the code causing the apparatus to select a cyclic shift for the scheduled SCI transmission performed by the apparatus includes code causing the apparatus to: randomly select a cyclic shift from a set of multiple cyclic shifts when the scheduled SCI transmission is an initial transmission, the set of multiple cyclic shifts excluding determined cyclic shifts for retransmissions of the one or more SCI transmissions performed by the one or more UEs that conflict with the scheduled SCI transmission performed by the apparatus.

12. The apparatus of claim 10, wherein the code causing the apparatus to select a cyclic shift for the scheduled SCI transmission performed by the apparatus includes code causing the apparatus to perform the following operation: when the scheduled SCI transmission is a retransmission and the cyclic shift for the initial transmission performed by the apparatus is different from one or more cyclic shifts determined by the one or more retransmissions of the one or more SCI transmissions performed for the one or more UEs, select the same cyclic shift for the initial transmission.

13. The apparatus of claim 10, wherein when the scheduled SCI transmission is a retransmission and the cyclic shift used for the initial transmission is the same as at least one of one or more cyclic shifts determined for the one or more retransmissions of the one or more SCI transmissions performed for the one or more UEs, the code causing the apparatus to select the cyclic shift to be used for the scheduled SCI transmission performed by the apparatus includes code causing the apparatus to perform the following operations: Select the same cyclic shift for the initial transmission performed by the device, or A cyclic shift is randomly selected from a set of multiple cyclic shifts, the set of multiple cyclic shifts excluding the determined one or more cyclic shifts used for retransmissions of one or more SCI transmissions performed by one or more UEs that conflict with the scheduled SCI transmissions performed by the device.

14. The apparatus of claim 10, wherein: The device and the one or more UEs are configured for cellular vehicle-to-everything (C-V2X) communication. The memory further includes code that causes the device to perform the following operation: monitor the one or more SCI transmissions from the one or more UEs in a subframe in the Physical Side Link Control Channel (PSCCH); The device and the one or more UEs are configured for transmission mode 4 for C-V2X communication, and the device and the one or more UEs autonomously select transmission resources.

15. A computer-readable medium having thereon stored computer-executable code for wireless communication by a first user equipment (UE), the computer-executable code comprising: Code used to monitor the transmission of one or more side link control information (SCI) messages from one or more second UEs; Code used to determine, based on the one or more SCIs, one or more retransmissions of the one or more SCI transmissions performed by the one or more second UEs that interfere with the scheduled SCI transmissions performed by the first UE; Code for selecting, at least based on the determination, the cyclic shift to be used for the scheduled SCI transmission of the first UE; Furthermore, the computer-executable code further includes: Code for determining one or more cyclic shifts for one or more retransmissions of one or more SCI transmissions performed for one or more second UEs based on one or more cyclic shifts performed for one or more SCI transmissions performed for one or more second UEs.

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