Apparatus and method for wireless communication by ue

Abstract

An apparatus and method for wireless communication by a first UE are provided. The apparatus comprises: at least one processor; and a memory coupled to the at least one processor, the memory comprising code executable by the at least one processor to cause the apparatus to: receive, from a second user equipment (UE), a sidelink control information (SCI) retransmission for a third UE; determining, based on the received SCI retransmission, that a first one or more resources for data retransmission are used by the third UE; and allocating resources for one or more subsequent transmissions excluding the use of the second one or more resources for SCI retransmission by the third UE and the first one or more resources for data retransmission.

Description

[0001] This application is a divisional application of the invention patent application with application date of May 14, 2021, application number 202180033755.X, and invention name “Relay physical side link control channel resources”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Application No. 17 / 319,699, filed on May 13, 2021, which claims the benefit of and priority to U.S. Provisional Application No. 63 / 025,724, filed on May 15, 2020, both of which are hereby assigned to the assignee of this application and are hereby expressly incorporated by reference in their entireties, as if fully set forth below and for all applicable purposes. Technical Field

[0004] Aspects of the present disclosure relate to wireless communications and, more particularly, to techniques for relaying physical sidelink control channel resources in sidelink communications. Background Art

[0005] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcast, etc. These wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access systems include 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) 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 a few.

[0006] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at a city level, a national level, a regional level, and even a global level. New radio (e.g., 5G NR) is an example of an emerging telecommunication standard. NR is an enhancement set to the LTE mobile standard released by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectrum efficiency, reducing costs, improving services, utilizing new spectrum, and better integrating with other open standards using OFDMA with cyclic prefix (CP) on the downlink (DL) and on the uplink (UL). To achieve these goals, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0007] However, as the demand for mobile broadband access continues to grow, there is a need to further improve NR and LTE technologies. These improvements should be applicable to other multi-access technologies and the telecommunication standards that adopt these technologies. Summary of the invention

[0008] The systems, methods, and devices of the present disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. After considering such discussion, and particularly after reading the section entitled "Detailed Description," one will understand how the features of the present disclosure provide advantages including relaying physical side link control information.

[0009] Certain aspects of the subject matter described in the present disclosure may be implemented in a method for wireless communication performed by a first user equipment (UE). The method generally includes receiving a sidelink control information (SCI) transmission from a second UE. The SCI points to one or more resources for retransmitting the SCI by the second UE. The method generally includes sending the SCI to a third UE using the one or more resources for retransmitting the SCI by the second UE.

[0010] Certain aspects of the subject matter described in the present disclosure may be implemented in a method for wireless communication by a first user equipment (UE). The method generally includes receiving an SCI retransmission for a third UE from a second UE. The method generally includes determining a first one or more resources for data retransmission by the third UE based on the received SCI retransmission. The method generally includes allocating resources for one or more subsequent transmissions, excluding a second one or more resources for SCI retransmission by the third UE and a first one or more resources for data retransmission.

[0011] Certain aspects of the subject matter described in the present disclosure may be implemented in an apparatus for wireless communication performed by a first user equipment (UE). The apparatus generally includes: at least one processor, and a memory coupled to the at least one processor. The memory includes code that can be executed by the at least one processor to enable the apparatus to receive an SCI transmission from a second UE. The SCI points to one or more resources for retransmitting the SCI by the second UE. The memory includes code that can be executed by the at least one processor to enable the apparatus to determine one or more resources for retransmitting the SCI based on the received SCI. The memory includes code that can be executed by the at least one processor to enable the apparatus to use one or more resources for retransmitting the SCI by the second UE to send the SCI to a third UE.

[0012] Certain aspects of the subject matter described in the present disclosure may be implemented in an apparatus for wireless communication by a first user equipment (UE). The apparatus generally includes: at least one processor, and a memory coupled to the at least one processor. The memory includes code that can be executed by the at least one processor to enable the apparatus to receive an SCI retransmission for a third UE from a second UE. The memory includes code that can be executed by the at least one processor to enable the apparatus to determine a first one or more resources for data retransmission by the third UE based on the received SCI retransmission. The memory includes code that can be executed by the at least one processor to enable the apparatus to perform the following operations: allocate resources for one or more subsequent transmissions, excluding a second one or more resources used by the third UE for SCI retransmission and a first one or more resources for data retransmission.

[0013] Certain aspects of the subject matter described in the present disclosure may be implemented in an apparatus for wireless communication performed by a first user equipment (UE). The apparatus generally includes a component for receiving an SCI transmission from a second UE. The SCI points to one or more resources for retransmitting the SCI by the second UE. The apparatus generally includes a component for sending the SCI to a third UE using the determined one or more resources for retransmitting the SCI by the second UE.

[0014] Certain aspects of the subject matter described in the present disclosure may be implemented in an apparatus for wireless communication by a first user equipment (UE). The apparatus generally includes a component for receiving an SCI retransmission for a third UE from a second UE. The apparatus generally includes a component for determining a first one or more resources for data retransmission by the third UE based on the received SCI retransmission. The apparatus generally includes a component for allocating resources for one or more subsequent transmissions, excluding a second one or more resources for SCI retransmission by the third UE and a first one or more resources for data retransmission.

[0015] Certain aspects of the subject matter described in the present disclosure may be implemented in a computer-readable medium having a computer executable file stored thereon for wireless communication by a first user equipment (UE). The computer-readable medium generally includes code for receiving an SCI transmission from a second UE. The SCI points to one or more resources for retransmitting the SCI by the second UE. The computer-readable medium generally includes code for sending the SCI to a third UE using the determined one or more resources for retransmitting the SCI by the second UE.

[0016] Certain aspects of the subject matter described in the present disclosure may be implemented in a computer-readable medium on which a computer executable file for wireless communication performed by a first user equipment (UE) is stored. The computer-readable medium generally includes code for receiving an SCI retransmission for a third UE from a second UE. The method generally includes determining a first one or more resources for data retransmission by the third UE based on the received SCI retransmission. The computer-readable medium generally includes code for allocating resources for one or more subsequent transmissions, excluding a second one or more resources for SCI retransmission by the third UE and a first one or more resources for data retransmission.

[0017] Certain aspects of the subject matter described in the present disclosure may be implemented in an apparatus for wireless communication by a first UE. The apparatus includes: at least one processor; and a memory coupled to the at least one processor, the memory including code executable by the at least one processor to cause the apparatus to perform the following operations: receiving sidelink control information SCI retransmissions for a third UE from a second user equipment UE; determining, based on the received SCI retransmissions, a first one or more resources to be used by the third UE for data retransmissions; and allocating resources for one or more subsequent transmissions, excluding the use of the second one or more resources for the SCI retransmissions and the first one or more resources for the data retransmissions by the third UE.

[0018] Certain aspects of the subject matter described in the present disclosure may be implemented in a method for wireless communication by a first UE. The method includes: receiving sidelink control information (SCI) retransmissions for a third UE from a second UE; determining, based on the received SCI retransmissions, first one or more resources to be used by the third UE for data retransmissions; and allocating resources for one or more subsequent transmissions, excluding use of second one or more resources for the SCI retransmissions and the first one or more resources for the data retransmissions by the third UE.

[0019] To achieve the foregoing and related ends, one or more aspects include features fully described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail certain illustrative features of one or more aspects. However, these features are only indicative of a few of the various ways in which the principles of the various aspects can be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order that the manner in which the features of the present disclosure described above can be understood in detail, a more specific description briefly summarized above may be understood by reference to various aspects, some of which are illustrated in the drawings. However, it should be noted that the drawings only illustrate certain aspects of the present disclosure, and the description may admit to other equivalent aspects.

[0021] Figure 1 is a block diagram conceptually illustrating an example wireless communication network in accordance with certain aspects of the present disclosure.

[0022] Figure 2 is a block diagram conceptually illustrating designs of example base stations (BSs) and user equipment (UEs) in accordance with certain aspects of the present disclosure.

[0023] Figure 3 is an example frame format for certain wireless communication systems (e.g., New Radio (NR)) in accordance with certain aspects of the present disclosure.

[0024] Figure 4A and Figure 4B Shown is a graphical representation of an example vehicle-to-everything (V2X) system in accordance with certain aspects of the present disclosure.

[0025] Figure 5A and Figure 5B An example scenario of vehicles at different distances from each other is shown in accordance with certain aspects of the present disclosure.

[0026] Figure 6 Example resources are shown when allocating resource blocks in cellular V2X (C-V2X) direct communications with packet collisions in accordance with certain aspects of the present disclosure.

[0027] Figure 7 is a table of parameters for sidelink transmissions in a C-V2X system according to certain aspects of the present disclosure.

[0028] Figure 8 Example resources for hybrid automatic repeat requests in accordance with certain aspects of the present disclosure are shown.

[0029] Fig. 9 is a flow diagram illustrating example operations for wireless communications by a first UE in accordance with certain aspects of the present disclosure.

[0030] Fig.10 is a flow diagram illustrating example operations for wireless communications by a first UE in accordance with certain aspects of the present disclosure.

[0031] Fig.11 An example call flow is shown when relaying resource blocks to avoid packet collisions in C-V2X direct communications, in accordance with certain aspects of the present disclosure.

[0032] Fig.12 Example resources are shown when allocating resource blocks to avoid packet collisions in C-V2X direct communications in accordance with certain aspects of the present disclosure.

[0033] Fig.13A communication device in accordance with aspects of the present disclosure is shown and may include various components configured to perform operations for the techniques disclosed herein.

[0034] Fig.14 A communication device in accordance with aspects of the present disclosure is shown and may include various components configured to perform operations for the techniques disclosed herein.

[0035] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized on other aspects without specific recitation. DETAILED DESCRIPTION

[0036] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for relaying physical sidelink control channel (PSCCH) communications, such as cellular vehicle-to-everything (C-V2X) direct communications.

[0037] In a C-V2X system, UEs such as vehicle user equipment (UE) can communicate directly with each other using time-frequency resources selected autonomously by the UE. However, the autonomous selection of resources may cause problems when two UEs select the same resource, causing packet collisions. For example, in some scenarios, during channel sensing and initial resource selection (e.g., autonomous semi-persistent scheduling (SPS) resource selection), the UE is "hidden" and may be interfering.

[0038] Therefore, in order to avoid packet collisions, various aspects of the present disclosure provide techniques for relaying PSCCH resources in sidelink communications. In some examples, a UE may relay sidelink control information (SCI) of another UE. The SCI relayed by the UE echoes and strengthens the SCI of another UE by sending the SCI on the same resources as the other UE. The hidden / attacker UE may receive the echoed SCI, stop sending on overlapping resources, and perform new resource selection that excludes the resources indicated by the received SCI.

[0039] The following description provides an example of relaying PSCCH resources in sidelink communications and is not a limitation on the scope, applicability or examples set forth in the claims. Without departing from the present disclosure, the functions and arrangements of the elements discussed may be changed. Various examples may omit, replace or add various programs or components as appropriate. For example, the described method may be performed in an order different from that described, and various steps may be added, omitted or combined. In addition, the features described in some examples may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement a device or practice method. In addition, the present disclosure is intended to cover this device or method practiced using other structures, functionalities or structures and functionalities other than or different from the various aspects of the present disclosure set forth herein. It should be understood that any aspect of the present disclosure disclosed herein may be embodied by one or more elements of the claims. The word "exemplary" used herein means "used as an example, instance or illustration". Any aspect described as "exemplary" herein is not necessarily interpreted as preferred or superior to other aspects.

[0040] In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a specific radio access technology (RAT) and may operate on one or more frequencies. RAT may also be referred to as a radio technology, air interface, etc. Frequency may also be referred to as a carrier, subcarrier, frequency channel, tone, subband, etc. Each frequency may support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs.

[0041] The techniques described herein can be used for various wireless networks and radio technologies. Although terms commonly associated with 3G, 4G, and / or new radio (e.g., 5G NR) wireless technologies may be used herein to describe various aspects, various aspects of the present disclosure can be applied in other communication systems based on generations.

[0042] Example Wireless Communication Network

[0043] New radio access such as 5G NR can support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth, millimeter wave (mmW), massive machine type communication MTC (mMTC) targeting non-backward compatible MTC technology, and / or mission critical targeting ultra-reliable low latency communication (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTIs) to meet corresponding quality of service (QoS) requirements. In addition, these services can coexist in the same subframe. NR supports beamforming, and the beam direction can be dynamically configured. Multiple input multiple output (MIMO) transmission with precoding can also be supported. The MIMO configuration in DL can support up to 8 transmit antennas, with multi-layer DL transmission of up to 8 streams and up to 2 streams per UE. Multi-layer transmission of up to 2 streams per UE can be supported. Aggregation of multiple cells can be supported with up to 8 serving cells.

[0044] Figure 1 An example wireless communication network 100 is shown in which aspects of the present disclosure may be performed. For example, the wireless communication network 100 may be a NR system (e.g., a 5G NR network). Figure 1 As shown, the wireless communication network 100 may communicate with a core network 132. The core network 132 may communicate with one or more base stations (BSs) 110a-100z (each base station is also individually referred to herein as BS110 or collectively referred to herein as BS110) and / or user equipments (UEs) 120a-120y (each user equipment is also individually referred to herein as UE 120 or collectively referred to herein as UE 120) via one or more interfaces.

[0045] According to certain aspects, UE 120 may be configured for sidelink communications. Figure 1 As shown, UE 120a includes a side link manager 122, which can be configured to relay the SCI of another UE according to aspects of the present disclosure. UE 120b can include a side link manager 112, which can be configured to receive the broadcast SCI and redetermine the side link resource allocation excluding the resources indicated in the SCI.

[0046] BS 110 may provide communication coverage for a particular geographic area, sometimes referred to as a "cell," which may be fixed or may move depending on the location of mobile BS 110. In some examples, BS 110 may be interconnected with each other and / or with one or more other BSs or network nodes (not shown) in wireless communication network 100 through various types of backhaul interfaces (e.g., direct physical connections, wireless connections, virtual networks, etc.) using any suitable transport network. Figure 1 In the example shown in FIG. 1 , BSs 110a, 110b, and 110c may be macro BSs for macro cells 102a, 102b, and 102c, respectively. BS 110x may be a pico BS for pico cell 102x. BSs 110y and 110z may be femto BSs for femto cells 102y and 102z, respectively. A BS may support one or more cells.

[0047] BS 110 communicates with UE 120 in wireless communication network 100. UE 120 (e.g., 120x, 120y, etc.) may be distributed throughout wireless communication network 100, and each UE 120 may be stationary or mobile. Wireless communication network 100 may also include a relay station (e.g., relay station 110r, also referred to as a relay device, etc.) that receives transmissions of data and / or other information from an upstream station (e.g., BS 110a or UE 120r) and sends transmissions of data and / or other information to a downstream station (e.g., UE 120 or BS 110), or relays transmissions between UE 120 to facilitate communication between devices.

[0048] The network controller 130 may communicate with a set of BSs 110 and provide coordination and control (e.g., via a backhaul) for these BSs 110. In various aspects, the network controller 130 may communicate with a core network 132 (e.g., a 5G core network (5GC)), which provides various network functions such as access and mobility management, session management, user plane functions, policy control functions, authentication server functions, unified data management, application functions, network exposure functions, network repository functions, network slice selection functions, etc.

[0049] Figure 2 BS 110 and UE 120 (eg, Figure 1 The present invention provides example components of a wireless communication network 100 that may be used to implement aspects of the present disclosure.

[0050] At BS 110a, a transmit processor 220 may receive data from a data source 212 and control information from a controller / processor 240. The control information may be for a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical hybrid ARQ indicator channel (PHICH), a physical downlink control channel (PDCCH), a group common PDCCH (GC PDCCH), etc. The data may be for a physical downlink shared channel (PDSCH), etc. A medium access control (MAC)-control element (MAC-CE) is a MAC layer communication structure that may be used for control command exchange between wireless nodes. The MAC-CE may be carried in a shared channel such as a physical downlink shared channel (PDSCH), a physical uplink shared channel (PUSCH), or a physical sidelink shared channel (PSSCH).

[0051] The processor 220 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor 220 may also generate reference symbols, such as for a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a PBCH demodulation reference signal (DMRS), and a channel state information reference signal (CSI-RS). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, and / or reference symbols (if applicable), and may provide an output symbol stream to a modulator (MOD) in a transceiver 232a-232t. Each modulator in the transceiver 232a-232t may process a corresponding output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may 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 may be transmitted via antennas 234a-234t, respectively.

[0052] At UE 120a (or similarly, at UE 120b), antennas 252a-252r can receive downlink signals from BS 110a and can provide received signals to demodulators (DEMODs) in transceivers 254a-254r, respectively. Each demodulator in transceivers 254a-243r can condition (e.g., filter, amplify, downconvert, and digitize) a corresponding received signal to obtain input samples. Each demodulator can further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. MIMO detector 256 can obtain received symbols from all demodulators in transceivers 254a-254r, perform MIMO detection on the received symbols (if applicable), and provide detected symbols. The receive processor 258 may process (eg, demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 120a to a data sink 260 , and provide decoded control information to a controller / processor 280 .

[0053] On the uplink and / or sidelink, at the UE 120a, a transmit processor 264 may receive and process data from a data source 262 (e.g., for a physical uplink shared channel (PUSCH)) and control information from a controller / processor 280 (e.g., for a physical uplink control channel (PUCCH) or a physical sidelink control channel (PSSCH)). The transmit processor 264 may also generate reference symbols for reference signals (e.g., for a sounding reference signal (SRS)). The symbols from the transmit processor 264 may be precoded by the TX MIMO processor 266 (if applicable), further processed by a modulator in the transceiver 254a-254r (e.g., for SC-FDM, etc.), and transmitted to the BS 110a or UE 120b. At BS 110a, the uplink signal from UE 120a may be received by antenna 234, processed by demodulators in transceivers 232a-232t, detected by MIMO detector 236 (if applicable), and further processed by receive processor 238 to obtain decoded data and control information sent by UE 120a. Receive processor 238 may provide decoded data to data sink 239 and decoded control information to controller / processor 240.

[0054] Memories 242 and 282 may store data and program codes for BS 110a and UE 120a, respectively.A scheduler 244 may schedule UEs for data transmission on the downlink and / or uplink.

[0055] The antennas 252, processors 266, 258, 264, and / or controller / processor 280 of the UE 120a may be used to perform the various techniques and methods described herein. Figure 2 As shown, the controller / processor 280 of UE 120a has a side link manager 281, which can be configured to relay PSCCH resources in side link communications according to various aspects described herein. Although shown at the controller / processor, other components of UE 120a can be used to perform the operations described herein.

[0056] NR can utilize orthogonal frequency division multiplexing (OFDM) with cyclic prefix (CP) on uplink and downlink. NR can support 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 also commonly referred to as tones, bins, etc. Each subcarrier can be modulated with data. Modulation symbols can be sent 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 can support a basic subcarrier spacing (SCS) of 15KHz, and other SCSs can be defined relative to the basic SCS (for example, 30kHz, 60kHz, 120kHz, 240kHz, etc.).

[0057] Figure 3 300 for NR. The transmission timeline for each of the downlink and uplink can be divided into units of radio frames. Each radio frame can have a predetermined duration (e.g., 10ms) and can be divided into 10 subframes, each of which is 1ms and indexed from 0 to 9. Each subframe can include a variable number of slots (e.g., 1, 2, 4, 8, 16... slots), depending on the SCS. Each slot can include a variable number of symbol periods (e.g., 7, 12, or 14 symbols), depending on the SCS. The symbol period in each slot can be assigned an index. The subslot structure can refer to a transmission time interval (e.g., 2, 3, or 4 symbols) having a duration less than the slot. Each symbol in the slot can be configured for a link direction (e.g., DL, UL, or flexible) for data transmission, and the link direction of each subframe can be dynamically switched. The link direction can be based on the slot format. Each slot can include DL / UL data and DL / UL control information.

[0058] Example Sidelink Communications

[0059] In some examples, communication between a user equipment (e.g., such as UE 120 in wireless communication network 100) and a base station (e.g., such as BS 110 in wireless communication network 100) is referred to as an access link. The access link may be provided via a Uu interface. Communication between devices such as UE 120 may be referred to as a side link.

[0060] In some examples, two or more subordinate entities (e.g., UE 120) use sidelink signals to communicate with each other. Real-world applications of this sidelink communication may include public safety, near-side services, UE-to-network relay, vehicle-to-vehicle (V2V) communication, Internet of Everything (IoE) communication, Internet of Things (IoT) communication, mission-critical grids, and / or various other suitable applications. In general, a sidelink signal may refer to a signal communicated 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 BS110), even if the scheduling entity can be utilized for scheduling and / or control purposes. In some examples, the sidelink signal may communicate using a licensed spectrum (unlike a wireless local area network that typically uses an unlicensed spectrum). An example of a sidelink communication is PC5, for example, as used in V2V, LTE, and / or NR.

[0061] Various sidelink channels may be used for sidelink communications, including a physical sidelink discovery channel (PSDCH), a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), and a physical sidelink feedback channel (PSFCH). The PSDCH may carry discovery expressions that enable near-side devices to discover each other. The PSCCH may carry control signaling such as sidelink resource configuration and other parameters for data transmission, and the PSSCH may carry data transmission. The PSFCH may carry feedback, such as CSI related to sidelink channel quality.

[0062] Figure 4A and Figure 4B A graphical representation of an example V2X system according to certain aspects of the present disclosure is shown. For example, Figure 4A and Figure 4B The illustrated vehicles may communicate via a sidelink channel and may relay sidelink transmissions as described herein.

[0063] Figure 4A and Figure 4B The V2X system provided in provides two complementary transmission modes. Figure 4AThe first transmission mode (also referred to as Mode 4) shown by way of example in FIG. 4 involves direct communication between participants that are close to each other within a local area (eg, also referred to as sidelink communication). Figure 4B The second transmission mode (also referred to as Mode 3) shown by way of example in FIG. 5 involves network communication through a network, which may be achieved through a Uu interface (eg, a wireless communication interface between a radio access network (RAN) and a UE).

[0064] refer to Figure 4A , shows a V2X system 400 (e.g., including vehicle-to-vehicle (V2V) communications) with two vehicles 402, 404. A first transmission mode allows direct communication between different participants in a given geographic location. As shown, the vehicles can have a wireless communication link 406 with an individual (V2P) (e.g., via a UE) through a PC5 interface. Communication between vehicles 402 and 404 can also occur through a PC5 interface 408. In the same manner, communication can occur from vehicle 402 to other highway components (e.g., highway components 410, such as traffic signals or signs) (V2I) through a PC5 interface 412. Figure 4A For each communication link shown, bidirectional communication can occur between the elements so each element can be a sender and receiver of information. The V2X system 400 can be a self-managing system that is implemented without assistance from a network entity. A self-managing system can enable improvements in spectrum efficiency, reductions in cost, and increases in reliability because no network service interruptions occur during handoff operations for moving vehicles. The V2X system can be configured to operate in a licensed or unlicensed spectrum so any vehicle with an equipped system can access a common frequency and share information. This coordinated / common spectrum operation allows for safe and reliable operation.

[0065] Figure 4B A V2X system 450 is shown for communication between vehicle 452 and vehicle 454 through network entity 456. These network communications can occur through discrete nodes, such as a BS (e.g., BS 110a), which sends and receives information to vehicles 452, 454 (e.g., relays information between them). Network communications through vehicle-to-network (V2N) links 458 and 410 can be used, for example, for long-range communications between vehicles, such as for communicating the presence of an automobile accident a certain distance ahead along a road or highway. Other types of communications can be issued by wireless nodes to vehicles, such as traffic flow conditions, road hazard warnings, environmental / weather reports, and service station availability, among other examples. This data can be obtained from a cloud-based sharing service.

[0066] Roadside units (RSUs) may be utilized. RSUs may be used for V2I communications. In some examples, RSUs may act as forwarding nodes to extend the coverage of UEs. In some examples, RSUs may be co-located with BSs, or may be independent. RSUs may have different classifications. For example, RSUs may be classified as UE-type RSUs and macro NodeB-type RSUs. Macro NB-type RSUs have functionality similar to macro eNB / gNBs. Macro NB-type RSUs may utilize the Uu interface. UE-type RSUs may be used to meet stringent quality of service (QoS) requirements by minimizing conflicts and improving reliability. UE-type RSUs may use centralized resource allocation mechanisms to allow efficient resource utilization. Critical information (e.g., such as traffic conditions, weather conditions, congestion statistics, sensor data, etc.) may be broadcast to UEs in the coverage area. Relays may rebroadcast critical information received from some UEs. UE-type RSUs may be reliable synchronization sources.

[0067] As mentioned above, aspects of the present disclosure relate to sidelink communications, which may include cellular V2X (C-V2X) communications. C-V2X systems may operate in various modes. An example mode, referred to as Mode 3, may be used when a UE is within a coverage area. In Mode 3, the network may control the allocation of resources for the sidelink UE. In another example mode for a V2X system, referred to as Mode 4, the sidelink UEs may 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 may autonomously select resources based on an SPS algorithm. The SPS algorithm may be configured, hard-coded, or pre-configured at the UE. For example, the SPS algorithm may be based on an SPS algorithm defined in a 3GPP technical standard.

[0068] In some cases, due to dynamic changes in the environment, a "hidden terminal" scenario may occur. For example, when a sidelink UE selects resources for transmission (e.g., in Mode 4), some other UEs (e.g., vehicles) may be hidden (e.g., not detected), such as when performing channel sensing. Therefore, two (or more) UEs may (e.g., autonomously) select the same resources. A hidden terminal scenario may occur (resulting in a packet collision) when UEs have overlapping coverage areas while allocating RBs for transmission.

[0069] Figure 5A A hidden terminal scenario is shown. UE A and UE C cannot sense each other's presence, for example, because these UEs are out of each other's coverage. Figure 5A As shown, the physical distance d between UE A and UE C is greater than r A And also greater than r C , where r Ais the coverage radius of UE A, and r C is 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, the two UEs may allocate / select the same time-frequency resources (some or all) for transmission (e.g., overlapping RBs). In this case, due to packet collisions, UEs (such as Figure 5B UE B) is shown unable to decode data sent from UE A or UE C using the allocated resources.

[0070] In some systems, the UE may use a sensing mechanism to select resources to transmit. By sensing available and unavailable resources, the UE may select idle resources and transmit on them, which may reduce or prevent conflicts. Sensing may involve power estimation (e.g., resource signal strength indicator (RSSI) measurement). The power estimation may exclude subframes that have not been measured (e.g., due to previous transmissions). Resource selection may exclude resources based on expected conflicts with transmissions from other UEs. However, hidden UEs may not be aware of each other and, therefore, cannot exclude each other's resources. Therefore, the transmissions of these UEs may collide on neighboring UEs.

[0071] Conflicts and overlaps can be seen in congestion scenarios. Figure 6 An example conflict scenario is shown. Figure 6 As shown, UE1 and UE3 may be hidden from each other. For example, UE1 transmits SCI in PSCCH 610 and PSSCH 612 (RV0), and UE2 may receive PSCCH transmission 610 and PSSCH transmission 612 of UE1 as well as PSSCH transmission, however, UE3 may not detect UE1's transmission, and therefore, does not exclude UE1's resources from resource reselection and may use the same resources for its transmission. Figure 6 As shown, UE2 may receive a transmission 618 from UE3 that collides with and / or overlaps with the transmission from UE1 (PSCCH 614 and PSSCH RV2 616). Figure 6 Three UEs are shown in FIG, but the system may involve more than three UEs.

[0072] For PSCCH, bit processing may follow the downlink control information (DCI), where no scrambling is performed in the cyclic redundancy check (CRC) attachment. Scrambling may be performed with a constant (e.g., c init=510). PSCCH can be initialized using quadrature phase shift keying (QPSK) modulation. Layer mapping and precoding can use a single antenna port. SCI can be sent in PSCCH and include payload and uncoded bits. The same SCI can include the same transmitted symbols (e.g., coded, modulated, mapped symbols). Figure 7 is a parameter table of reference signals for PSCCH transmission. Reference signals for PSSCH may not use group or sequence hopping and use the same orthogonal code. Reference signals for PSSCH may have cyclic shifts that provide channel separation (e.g., four randomly selected values ​​{0,3,6,9}).

[0073] Information about the sidelink transmission 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 indicated period of the SPS transmission. In another example, a hybrid automatic repeat request (HARQ) transmission may involve a bundling mechanism and control (e.g., 1 / 2 / ...15 subframe gaps). For example, redundancy versions (e.g., RV0, RV2) can be associated. Therefore, information about one RV can be determined from information about another RV. In C-V2X transmissions, the cyclic shift used for RV2 can be randomly selected (similar to the cyclic shift used for RV0). As Figure 8 As shown, the initial transmission (SCI and PSSCH RV0) is in the first subframe SF N From the first subchannel SCH i The transmission starts at the second subframe SF. N+K After K subframe intervals, the second subchannel SCH j Start sending. Subframe SF N SCI_0 in the subframe points to the SF N Based on the association of RV0 with RV2, the subframe and starting subchannel for retransmission can be determined from the initial transmission.

[0074] In some examples, the cyclic shift for RV2 may be the same as the randomly selected cyclic shift for RV0. In some cases, a notification bit may be introduced to the SCI. RV0 and RV2 may point to each other and may implicitly indicate the SCI of the paired RVs and / or may indicate the CS of the paired RVs. Figure 8 An example SCI RV pair is shown.

[0075] In some systems (e.g., in TS 36.211 Section 9.8), for sidelink transmission modes 3 and 4 on 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 TS 36.211 Section 14.2.1). Randomly selecting a cyclic shift can help handle collisions.

[0076] Congestion in transmissions (such as conflicts due to hidden UE scenarios) may be detrimental to C-V2X communications and may lead to the advancement of competition (e.g., dedicated short range communications (DSRC)). Congestion in transmissions may affect packet error rate (PER) and / or information age (IA).

[0077] Therefore, what are needed are techniques and apparatus for reducing collisions in sidelink communications.

[0078] Example relay physical sidelink control channel resources in sidelink communications

[0079] Various aspects of the present disclosure provide techniques for relaying physical sidelink control channel (PSSCH) resources in sidelink communications, such as in a cellular vehicle-to-everything (C-V2X) system. For example, various aspects can help enable cost-free relaying to avoid the above-described FIG. Figure 8 Conflict in the "Hidden Terminal" scenario discussed.

[0080] Various aspects of the present disclosure relate to relaying PSCCH transmissions to enhance (e.g., echo on the same resources) PSCCH transmissions. Enhanced PSCCH transmissions may include sending sidelink control information (SCI) on the same resources by multiple sidelink devices. Some aspects provide combined enhancement by using the same cyclic shift for the echoed SCI transmissions. Some aspects provide diversity enhancement by using the same cyclic shift for the echoed SCI transmissions.

[0081] Although some figures and examples in the present disclosure involve three user equipments (eg, UE1, UE2, UE3), aspects of the present disclosure may be applied to any number of UEs. For example, there may be multiple hidden / attacker terminals, multiple victim UEs, etc.

[0082] Fig. 9 and Fig.10 1000 are flow charts illustrating example operations 900 and 1000, respectively, for wireless communication according to certain aspects of the present disclosure. For example, operations 900 and 1000 may be performed by a first user equipment (e.g., UE 120a in wireless communication network 100). Operations 900 and 1000 may be implemented as a processor (e.g., Figure 2In addition, for example, the antennas (e.g., Figure 2 The antenna 252 of the UE is used to enable the transmission and reception of signals by the UE in operations 900 and 1000. In certain aspects, the transmission and reception of signals by the UE can be implemented via a bus interface of one or more processors (e.g., controller / processor 280) that obtain and / or output signals.

[0083] Operations 900 may begin at 902 by receiving an SCI transmission from a second UE, the SCI pointing to one or more resources for retransmitting the SCI by the second UE.

[0084] In some aspects, at 904, the UE determines a cyclic shift of the received SCI and determines to use the same cyclic shift or a different cyclic shift for sending the SCI to a third UE.

[0085] In some aspects, at 906, the UE determines a transmit power of the received SCI and determines to use the same transmit power for transmitting the SCI to a third UE.

[0086] In some aspects, at 910, the UE adds an indication to the SCI going to the third UE that the SCI is an echo SCI of the SCI retransmitted by the second UE.

[0087] In some aspects, at 912, the UE randomly selects a cyclic shift for sending the SCI to the third UE.

[0088] At 914, the UE sends the SCI to the third UE using the one or more resources for retransmission. In some examples, when the UE sends the SCI to the third UE, the UE may broadcast, multicast, or unicast the SCI.

[0089] Operations 1000 may begin at 1002 by receiving an SCI retransmission for a third UE from a second UE.

[0090] At 1004, the UE determines first one or more resources to be used by a third UE for data retransmission based on the received SCI retransmission.

[0091] In some cases, at 1006, the UE determines one or more resources to be used by a third UE to send the SCI and data associated with the first redundancy version (RV).

[0092] In some cases, at 1008, the UE excludes resource(s) used to determine resources allocated for one or more subsequent transmissions.

[0093] At 1010, the UE allocates resources for one or more subsequent transmissions excluding the second one or more resources used for SCI retransmissions by the third UE and the first one or more resources used for data retransmissions.

[0094] According to certain aspects, when multiple UEs (e.g., UE1, UE3) are scheduled to transmit on the same subframe (e.g., on non-overlapping RVs, such as RV2), the neighboring UEs can reinforce the (one or more) PSCCH transmissions of one or more of the UEs by relaying / echoing the PSCCH transmissions on the same RV resources. In some aspects, relaying the PSCCH transmission involves echoing a PSCCH transmission containing the same (one or more) SCIs. For example, a first aggressor UE and a second aggressor UE transmit to a neighboring UE on the same resources, and the neighboring UE echoes the PSCCH transmission of the first aggressor UE. When the second aggressor UE receives the echo of the PSCCH transmission from the neighboring UE, the aggressor UE abandons using the same resources as the previous transmission for further transmission.

[0095] like Fig.11 As shown, in the first subframe SF_N, UE2 receives the initial transmission of UE1, RV0PSCCH transmission 1102, which can provide SCI and information about PSSCH RV0 transmission 1104, and uses SCI to receive PSSCH RV0 transmission 1104 in SF_N. Figure 6 As discussed, UE3 may be "hidden" and not receive UE1's transmission in SF_N. Based on UE1's RV0 transmission, UE2 may determine the location (e.g., subframe and starting subchannel) of UE1's corresponding RV2 transmission (e.g., based on a configured / known association between RV0 and RV2). For example, UE2 determines the location of UE1's PSCCH 1106 and PSSCH 1108 retransmissions in subframe SF_N+K, and UE2 echoes UE1's PSCCH 1106RV2 retransmissions in the same subframe SF_N+K. UE2 may echo PSCCH 1106 without the corresponding SSCH 1108. UE3 may detect UE1's PSCCH 1106 retransmission echoed from UE2 even when UE3 cannot detect PSCCH 1106 from UE1. Thus, UE3 is aware of UE1's resources. For example, UE3 may determine UE1's corresponding RV0 transmission (PSCCH 1102 and PSSCH 1104) based on the received echoed RV2 PSCCH transmission 1106. UE3 may then exclude UE1's resources and perform a new resource selection.

[0096] In some aspects, the relay / echo PSCCH may use the same power as that used by a neighboring (eg, relay / echo) UE to send its own PSSCH transmission. The power used by the neighboring UE may be 3dB higher than that used for its PSSCH transmission.

[0097] In some aspects, when the cyclic shift is known, then the neighboring UEs may control the type of enhancement (eg, combining or diversity). In some aspects, when the cyclic shift is unknown, the neighboring UEs may randomly select a cyclic shift for enhanced PSCCH.

[0098] Aspects of the present disclosure allow for multiple PSCCH transmissions between an aggressor UE and neighboring UEs.

[0099] Some aspects allow for PSCCH transmission without a corresponding PSSCH transmission.

[0100] Some aspects of the present disclosure relate to adding an indicator to a PSCCH transmission that indicates that the PSCCH transmission is an echoed PSCCH transmission. In some examples, the SCI may also include an indicator indicating that the PSCCH transmission has passed a reference signal received power (RSRP) threshold for neighboring UEs to echo the PSCCH transmission. In some examples, a UE receiving a relay / echo SCI can take the SCI into account when excluding resources for resource selection - even when the SCI is received without a corresponding PSSCH (e.g., based on a bit indicating that the SCI is an echoed PSCCH transmission). Selecting different cyclic shifts between PSCCH transmissions can reduce the probability of detection unless the indicator is not protected and is not included in the cyclic redundancy check (CRC) calculation.

[0101] The control information may point to RV0 for a subsequent subframe. In some aspects, channel state information (CSI) (eg, phase 2) may be an enhancement to RV0 (eg, without waiting for RV2).

[0102] Aspects of the present disclosure increase CV2X coverage and enable cost-free relaying since the relayed / echoed PSCCH transmissions are done on already occupied resources.

[0103] Fig.12 is a call flow illustrating example signaling 1200 for relaying SSCH. Fig.12As shown, at 1202, UE1 (e.g., UE 120a) determines a resource set for communication. At 1204, UE3 (e.g., 120c) determines a resource set for communication. The determination of resources can be based on an autonomous SPS resource allocation algorithm. UE1 and UE3 each use the determined resources to send information about its determined resource set and / or transmission (e.g., SCI transmission) using the determined resources to UE2 (e.g., 120b) at 1206 and 1208, respectively. At 1210, UE2 determines the resources for retransmitting the SCI transmission based on the SCI transmission received from UE1. At 1214, UE2 uses the determined resources to send (e.g., broadcast, unicast, or multicast) SCI to UE3 to echo the SCI retransmission of UE1 at 1212. In response to the SCI, UE3 excludes the determined resources and determines a new resource set for transmission that excludes overlapping resources at 1216. After determining the new set of resources, UE3 may use the new resources for further sidelink transmissions at 1218 .

[0104] Fig.13 A communication device 1300 is shown, which may include devices configured to perform operations for the techniques disclosed herein (such as Fig. 9 1300). The communication device 1300 includes a processing system 1302 coupled to a transceiver 1308 (e.g., a transmitter and / or a receiver). The transceiver 1308 is configured to transmit and receive signals for the communication device 1300 via an antenna 1310, such as the various signals described herein. The processing system 1302 may be configured to perform processing functions for the communication device 1300, including processing signals received by and / or to be transmitted by the communication device 1300.

[0105] The processing system 1302 includes a processor 1304 coupled to a computer readable medium / memory 1312 via a bus 1306. In some aspects, the computer readable medium / memory 1312 is configured to store instructions (e.g., computer executable code) that, when executed by the processor 1304, cause the processor 1304 to perform Fig. 913 or other operations for performing the various techniques discussed herein for relaying PSCCH resources in C-V2X direct communication. In certain aspects, the computer-readable medium / memory 1312 stores: code 1314 for receiving an SCI transmission from a second UE, the SCI pointing to one or more resources for retransmitting the SCI by the second UE; code 1318 for sending the SCI to a third UE using one or more resources for retransmitting the SCI by the second UE. In certain aspects, the computer-readable medium / memory 1312 may store code 1320 for determining a cyclic shift of the received SCI and determining to use the same cyclic shift or a different cyclic shift for sending the SCI to the third UE. In certain aspects, the computer-readable medium / memory 1312 may store code 1322 for determining a transmit power of the received SCI and for determining to use the same transmit power for sending the SCI to the third UE. In certain aspects, the computer-readable medium / memory 1312 may store code 1324 for adding an indication in the SCI to the third UE that the SCI is an echo SCI of the SCI retransmitted by the second UE. In certain aspects, the computer-readable medium / memory 1312 may store code 1326 for randomly selecting a cyclic shift for sending the SCI to the third UE. In certain aspects, the processor 1304 has circuitry configured to implement the code stored in the computer-readable medium / memory 1312. The processor 1304 includes circuitry 1334 for receiving an SCI from the second UE, the SCI pointing to a retransmission of the SCI; and circuitry 1338 for sending the SCI to the third UE using one or more resources for the retransmission. In certain aspects, the processor 1304 may include circuitry 1340 for determining a cyclic shift of the received SCI and determining to use the same cyclic shift or a different cyclic shift for sending the SCI to the third UE. In certain aspects, processor 1304 may include circuitry 1342 for determining a transmit power of the received SCI and determining to use the same transmit power for transmitting the SCI to the third UE. In certain aspects, processor 1304 may include circuitry 1344 for adding in the SCI to the third UE an indication that the SCI is an echo SCI of an SCI retransmitted by the second UE. In certain aspects, processor 1304 may include circuitry 1446 for randomly selecting a cyclic shift for transmitting the SCI to the third UE.

[0106] For example, means for transmitting (or means for outputting for transmitting) may include Figure 2 The transmitter unit 254 and / or antenna(s) 252 of the UE 120a shown in FIG. Fig.13The circuit 1338 of the communication device 1300 in FIG. The means for receiving (or the means for obtaining) may include Figure 2 1 and / or the receiver and / or antenna(s) 252 of the UE 120a shown in FIG. Fig.13 The circuit 1334 of the communication device 1300 in FIG. 1300. The means for communicating may include a transmitter, a receiver, or both. The means for generating, the means for executing, the means for determining, the means for taking action, the means for determining, and the means for coordinating may include a processing system, which may include one or more processors, such as Figure 2 The receive processor 258, transmit processor 264, TX MIMO processor 266 and / or controller / processor 280 of the UE 120a shown in FIG. Fig.13 The processing system 1302 of the communication device 1300 in FIG.

[0107] Fig.14 A communication device 1400 is shown, which may include devices configured to perform operations for the techniques disclosed herein (such as Fig.10 1400). The communication device 1400 includes a processing system 1402 coupled to a transceiver 1408 (e.g., a transmitter and / or a receiver). The transceiver 1408 is configured to transmit and receive signals for the communication device 1400, such as the various signals described herein, via an antenna 1410. The processing system 1402 may be configured to perform processing functions for the communication device 1400, including processing signals received by and / or to be transmitted by the communication device 1400.

[0108] The processing system 1402 includes a processor 1404 coupled to a computer-readable medium / memory 1412 via a bus 1506. In certain aspects, the computer-readable medium / memory 1412 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 1404, cause the processor 1404 to perform Fig.101410 or other operations for performing the various techniques discussed herein for relaying PSCCH resources in C-V2X direct communication. In certain aspects, the computer-readable medium / memory 1412 stores: code 1414 for receiving an SCI retransmission for a third UE from a second UE; code 1416 for determining a first one or more resources for data retransmission by the third UE based on the received SCI retransmission; and code 1418 for allocating resources for one or more subsequent transmissions, excluding the second one or more resources used for SCI retransmission by the third UE and the first one or more resources for data retransmission. In certain aspects, the computer-readable medium / memory 1412 may store: code 1420 for determining a third one or more resources used by the third UE to send SCI and data associated with the first RV; and code 1422 for excluding the third one or more resources used to determine the resources allocated for one or more subsequent transmissions. In certain aspects, the processor 1404 has circuitry configured to implement the code stored in the computer-readable medium / memory 1412. Processor 1404 includes: circuitry 1434 for receiving an SCI retransmission for a third UE from a second UE; circuitry 1436 for determining, based on the received SCI retransmission, first one or more resources for SCI retransmission by the third UE and second one or more resources for data retransmission associated with the SCI by the third UE; and code 1438 for excluding the first one or more resources and the second one or more resources for determining resources allocated for one or more subsequent transmissions. In certain aspects, processor 1404 may include: circuitry 1440 for determining a third one or more resources for sending SCI and data associated with the first RV by the third UE; and circuitry 1442 for excluding the third one or more resources for determining resources allocated for one or more subsequent transmissions.

[0109] For example, means for sending (or means for outputting for transmission) may include Figure 2 1 and 12. The transmitter unit 254 and / or antenna(s) 252 of the UE 120a shown in FIG. The means for receiving (or the means for obtaining) may include Figure 2 The receiver and / or (one or more) antenna 252 and / or Fig.14 The circuit 1434 of the communication device 1400 in FIG. 1400. The means for communicating may include a transmitter, a receiver, or both. The means for generating, the means for executing, the means for determining, the means for taking action, the means for determining, and the means for coordinating may include a processing system, which may include one or more processors, such as Figure 2The receive processor 258, transmit processor 264, TX MIMO processor 266 and / or controller / processor 280 of the UE 120a shown in FIG. Fig.14 The processing system 1402 of the communication device 1400 in FIG.

[0110] Example aspects

[0111] Examples of implementations are described in the following numbered clauses:

[0112] Aspect 1: A method for wireless communication performed by a first user equipment (UE), comprising: receiving a side link control information (SCI) transmission from a second UE, the SCI pointing to one or more resources for retransmitting the SCI by the second UE; and sending the SCI to a third UE using the one or more resources for retransmitting the SCI by the second UE.

[0113] Aspect 2: The method according to aspect 1, wherein the SCI is associated with a first redundancy version (RV), and the retransmission of the SCI is associated with a second RV.

[0114] Aspect 3: The method according to aspect 2, wherein determining one or more resources for retransmitting the SCI based on the first received SCI comprises determining the one or more resources based on a preconfigured association between the first RV and the second RV.

[0115] Aspect 4: The method according to any one of aspects 1 to 3, wherein determining the one or more resources comprises determining the one or more resources comprises frequency and time resources for retransmitting the SCI.

[0116] Aspect 5: The method according to any one of aspects 1 to 4, further comprising: determining a cyclic shift of the received SCI; and using the cyclic shift of the received SCI to send the SCI to a third UE.

[0117] Aspect 6: The method according to any one of aspects 1 to 5, further comprising: determining a cyclic shift of the received SCI; and using a different cyclic shift for sending the SCI to a third UE.

[0118] Aspect 7: The method according to any one of aspects 1 to 6, further comprising: determining a transmit power of the received SCI; and using the same transmit power for transmitting the SCI to a third UE.

[0119] Aspect 8: The method according to any one of aspects 1 to 7, further comprising: randomly selecting a cyclic shift for sending the SCI to the third UE.

[0120] Aspect 9: The method according to any one of aspects 1 to 8, wherein sending the SCI to the third UE includes sending the SCI to the third UE in a subframe and not sending data to the third UE using the SCI in the subframe.

[0121] Aspect 10: The method according to any one of aspects 1 to 9, further comprising: adding, in the SCI to the third UE, an indication that the SCI is an echo SCI of the SCI retransmitted by the second UE.

[0122] Aspect 11: A method according to any one of Aspects 1 to 10, wherein: the first UE, the second UE and the third UE are configured for cellular vehicle-to-everything (CV2X) communication; the first UE is configured to send SCI to the third UE in a physical sidelink control channel (PSCCH); the first UE is configured to receive SCI from the second UE in the PSCCH in a subframe; and the first UE is configured to receive data in a physical sidelink shared channel (PSSCH) from the second UE using the SCI in a subframe.

[0123] Aspect 12: A method of wireless communication performed by a first user equipment (UE), comprising: receiving a sidelink control information (SCI) retransmission for a third UE from a second UE; determining a first one or more resources for data retransmission by the third UE based on the received SCI retransmission; and allocating resources for one or more subsequent

[0124] Aspect 13: A method according to Aspect 12, wherein: SCI retransmission and data retransmission are associated with a second redundancy (RV); and the method further includes: determining a third one or more resources used by a third UE to send an SCI associated with the first RV and to send data associated with the first RV; and excluding the third one or more resources used for one or more subsequent transmissions.

[0125] Aspect 14: The method according to any one of aspects 12 to 13, wherein determining the third one or more resources comprises determining the third one or more resources based on a preconfigured association between the first RV and the second RV.

[0126] Aspect 15: The method according to any one of aspects 12 to 14, wherein the first one or more resources, the second one or more resources and the third one or more resources include frequency resources and time resources.

[0127] Aspect 16: The method according to any one of aspects 12 to 15, wherein the SCI retransmission from the second UE is received in the subframe without data transmission from the second UE in the subframe.

[0128] Aspect 17: The method according to any one of aspects 12 to 16, wherein the SCI retransmission from the second UE includes an indication that the SCI is an echo SCI of the SCI retransmitted by the third UE.

[0129] Aspect 18: A method according to any one of Aspects 12 to 17, wherein: the first UE, the second UE and the third UE are configured for cellular vehicle-to-everything (CV2X) communication; the first UE is configured to receive SCI retransmissions in a physical sidelink control channel (PSCCH); and the first UE is configured to receive data in a physical sidelink shared channel (PSSCH) from the second UE using SCI in a subframe.

[0130] Aspect 19: The method according to any one of aspects 12 to 18, wherein excluding one or more resources comprises excluding the first one or more resources and the second one or more resources when autonomously determining the allocated resources according to a semi-persistent scheduling (SPS) resource allocation algorithm.

[0131] Aspect 20: An apparatus comprising: means for performing the method according to any one of aspects 1 to 19.

[0132] Aspect 21: An apparatus comprising: at least one processor, and a memory coupled to the at least one processor, the memory comprising code executable by the at least one processor to cause the apparatus to perform the method according to any one of aspects 1 to 19.

[0133] Aspect 22: A computer readable medium having stored thereon computer executable code for wireless communication, which code, when executed by at least one processor, causes an apparatus to perform a method according to any one of aspects 1 to 19.

[0134] The techniques described herein can be used for various wireless communication technologies, such as NR (e.g., 5G NR), 3GPP Long Term Evolution (LTE), Advanced LTE (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" can often be used interchangeably. A CDMA network can implement radio technologies such as Universal Terrestrial Radio Access (UTRA), cdma2000, and the like. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95, and IS-856 standards. A TDMA network 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, Flash-OFDMA, etc. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). LTE and LTE-A are versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization named "3rd Generation Partnership Project (3GPP)". cdma2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2 (3GPP2)". NR is an emerging wireless communication technology under development.

[0135] In 3GPP, the term "cell" can refer to the coverage area of ​​a Node B (NB) and / or a NB subsystem serving the coverage area, depending on the context in which the term is used. In NR systems, the terms "cell" and BS, next-generation NodeB (gNB or gNodeB), access point (AP), distributed unit (DU), carrier, or transmit receive point (TRP) can be used interchangeably. The BS can provide communication coverage for macro cells, pico cells, femto cells, and / or other types of cells. A macro cell can cover a relatively large geographic area (e.g., a radius of several kilometers) and can allow unrestricted access by UEs with service subscriptions. A pico cell can cover a relatively small geographic area and can allow unrestricted access by UEs with service subscriptions. A femto cell can cover a relatively small geographic area (e.g., a home) and can allow limited access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, etc.). A BS for a macro cell can be referred to as a macro BS. A BS for a pico cell can be referred to as a pico BS. A BS for a femto cell can be referred to as a femto BS or a home BS.

[0136] UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a customer premises equipment (CPE), a cellular phone, a smart phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a home appliance, a medical device or medical equipment, a biosensor / device, a wearable device (such as a smart watch, smart clothing, smart glasses, a smart wristband, smart jewelry (e.g., a smart ring, a smart bracelet, etc.), an entertainment device (e.g., a music device, a video device, a satellite radio, etc.), a vehicle component or sensor, a smart meter / sensor, an industrial manufacturing equipment, a global positioning system device, or any other suitable device configured to communicate via a wireless or wired medium. 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 some other entity. A wireless node can provide, for example, a connection to or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. Some UEs can be considered Internet of Things (IoT) devices, which can be narrowband IoT (NB-IoT) devices.

[0137] In some examples, access to the air interface can be scheduled. The scheduling entity (e.g., BS) allocates communication resources for some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, allocating, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduling communications, subordinate entities utilize resources allocated by the scheduling entity. The base station is not the only entity that can act as a scheduling entity. In some examples, the UE may act as a scheduling entity and may schedule resources for one or more subordinate entities (e.g., one or more other UEs), and other UEs may utilize resources scheduled by the UE for wireless communications. In some examples, the UE may act as a scheduling entity in a peer-to-peer (P2P) network and / or a mesh network. In the mesh network example, in addition to communicating with the scheduling entity, the UEs may communicate directly with each other.

[0138] The methods disclosed herein include one or more steps or actions for implementing these methods. Method steps and / or actions can be interchangeable with each other. In other words, unless the specific order of steps or actions is specified, the order and / or purpose of specific steps and / or actions can be modified.

[0139] As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items, including single members. 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 multiples of the same elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, cc, and cccc or any other ordering of a, b, and c).

[0140] As used herein, the term "determine" encompasses a wide variety of actions. For example, "determine" may include computing, calculating, processing, deriving, investigating, searching (e.g., searching in a table, a database, or another data structure), ascertaining, etc. In addition, "determine" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), etc. In addition, "determine" may include resolving, selecting, choosing, establishing, etc.

[0141] The foregoing description is provided so that any person skilled in the art can practice the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects. Unless specifically stated otherwise, references to elements in the singular are not intended to mean "one and only one", but "one or more". Unless otherwise specifically stated, the term "some" refers to one or more. All structural and functional equivalents of elements of various aspects described throughout this disclosure that are known or will be known by those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, regardless of whether this disclosure is explicitly recorded in the claims, anything disclosed herein is not intended to be dedicated to the public. Any claim element is not interpreted under the provisions of 35 U.S.C. § 112 (f), unless the element is explicitly recorded using the phrase "parts for...", or in the case of a method claim, the element is recorded using the phrase "step for...".

[0142] The various operations of the method described above can be performed by any suitable component capable of performing the corresponding function. These components may include various hardware and / or (one or more) software components and / or (one or more) modules, including but not limited to circuits, digital signal processors (DSPs), application specific integrated circuits (ASICs) or processors (e.g., general or specially programmed processors). Typically, where there are operations shown in the figure, these operations may have corresponding components plus functional components with similar numbers.

[0143] The various illustrative logical blocks, modules, and circuits described in conjunction with the present disclosure may be implemented or executed with a general purpose processor, a DSP, an ASIC, a 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. A general purpose processor may be a microprocessor, but alternatively, 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, for example, a combination of a DSP and a microprocessor, a combination of multiple microprocessors, a combination of one or more microprocessors in conjunction with a DSP core, or any other combination of such configurations.

[0144] If implemented in hardware, an example hardware configuration may include a processing system in a wireless node. The processing system may be implemented with a bus architecture. The bus may include any number of interconnecting buses and bridges, depending on the specific application and overall design constraints of the processing system. The bus may link together various circuits including a processor, a machine-readable medium, and a bus interface. The bus interface may be used to connect a network adapter and others to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In a user terminal (see Figure 1 ), a user interface (e.g., keyboard, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link various other circuits, such as timing sources, peripherals, voltage regulators, power management circuits, etc., which are all known in the art and therefore will not be described again. The processor may be implemented with one or more general and / or special purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuits that can execute software. Those skilled in the art will recognize how to best implement the described functionality for the processing system depending on the specific application and the overall design constraints imposed on the entire system.

[0145] If implemented in software, the function can be stored or sent to a computer-readable medium as one or more instructions or codes. Software should be broadly interpreted as meaning instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or other. Computer-readable media include both computer storage media and communication media, and communication media include any media that facilitates the transfer of computer programs from one place to another. The processor may be responsible for managing the bus and general processing, including the execution of software modules stored on a machine-readable storage medium. A computer-readable storage medium may be coupled to a processor so that the processor can read information from the storage medium and write information to it. Alternatively, the storage medium may be integrated into the processor. For example, a machine-readable medium may include a transmission line, a carrier modulated by data, and / or a computer-readable storage medium having instructions stored thereon separated from a wireless node, all of which may be accessed by the processor through a bus interface. Alternatively or additionally, a machine-readable medium or any part thereof may be integrated into a processor, such as a case where a cache and / or a general register file may be provided. For 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, magnetic disks, optical disks, hard drives, or any other suitable storage media or any combination thereof. Machine-readable media may be embodied in a computer program product.

[0146] A software module may include a single instruction or many instructions, and may be distributed over several different code segments, among different programs, and over multiple storage media. A computer-readable medium may include several software modules. A software module includes instructions that, when executed by a device such as a processor, cause a processing system to perform various functions. A software module may include a sending module and a receiving module. Each software module may reside in a single storage device, or may be distributed over multiple storage devices. For example, when a triggering event occurs, a software module may be loaded from a hard drive into a RAM. During the execution of a software module, a processor may load some instructions into a cache to increase access speed. Then, one or more cache lines are loaded into a general register file for execution by a processor. When the functionality of a software module is mentioned below, it will be understood that this functionality is implemented by a processor when executing instructions from the software module.

[0147] Furthermore, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies (such as infrared (IR), radio and microwave), then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies (such as infrared, radio and microwave) are included in the definition of medium. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and A disk may be a computer-readable medium, wherein a disk typically reproduces data magnetically, while a disc reproduces data optically with a laser. Thus, in some aspects, a computer-readable medium may include a non-transitory computer-readable medium (e.g., a tangible medium). Additionally, for other aspects, a computer-readable medium may include a transitory computer-readable medium (e.g., a signal). Combinations of the above may also be considered examples of computer-readable media.

[0148] Thus, certain aspects may include a computer program product for performing the operations presented herein. For example, such a computer program product may include a computer-readable medium having instructions stored (and / or encoded) thereon, which instructions can be executed by one or more processors to perform the operations described herein, for example, for performing the operations described herein and in Fig. 9 and / or Fig.10 The operations shown in the instructions.

[0149] In addition, it should be understood that the modules and / or other appropriate components for performing the methods and techniques described herein can be downloaded and / or otherwise obtained by a user terminal and / or a base station (if applicable). For example, this device can be coupled to a server to facilitate the delivery of components for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage component (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or a floppy disk, etc.), so that the user terminal and / or the base station can obtain the various methods after being coupled to the device or providing the storage component to the device. In addition, any other suitable technology for providing the methods and techniques described herein to the device can be utilized.

[0150] It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the methods and apparatus described above.

Claims

1. An apparatus for wireless communication performed by a first user equipment UE, comprising: at least one processor; as well as a memory coupled to the at least one processor, the memory comprising code executable by the at least one processor to cause the apparatus to: receiving a sidelink control information SCI retransmission for a third UE from a second user equipment UE; determining, based on the received SCI retransmission, first one or more resources to be used by the third UE for data retransmission; as well as Allocating resources for one or more subsequent transmissions excludes use of the second one or more resources for the SCI retransmission and the first one or more resources for the data retransmission by the third UE.

2. The device according to claim 1, wherein: The SCI retransmission and the data retransmission are associated with a second redundant RV; and The memory also includes code executable by the at least one processor to cause the apparatus to: determining a third one or more resources to be used by the third UE for transmitting an SCI associated with the first RV and for transmitting data associated with the first RV; and The third one or more resources are excluded from use for the one or more subsequent transmissions.

3. The device according to claim 1, wherein: The code executable by the at least one processor to cause the apparatus to determine the third one or more resources includes: Code executable by the at least one processor to cause the apparatus to determine the third one or more resources based on a preconfigured association between the first RV and the second RV.

4. The device according to claim 1, wherein: The first one or more resources, the second one or more resources, and the third one or more resources include frequency resources and time resources.

5. The device according to claim 1, wherein: The SCI retransmission from the second UE is received in the subframe in the absence of a data transmission from the second UE in the subframe.

6. The device according to claim 1, wherein: The SCI retransmission from the second UE includes an indication that the SCI is an echo SCI of an SCI retransmitted by the third UE.

7. The device according to claim 1, wherein: The apparatus, the second UE and the third UE are configured for cellular vehicle-to-everything CV2X communication; The apparatus is configured to receive an SCI retransmission in a physical sidelink control channel, PSCCH; as well as The apparatus is configured to receive data in a physical sidelink shared channel (PSSCH) from the second UE using the SCI in a subframe.

8. The device according to claim 1, wherein: The code executable by the at least one processor to cause the apparatus to allocate one or more resources includes: The code is executable by the at least one processor to cause the apparatus to autonomously allocate resources according to a semi-persistent scheduling (SPS) resource allocation algorithm.

9. A method for wireless communication performed by a first user equipment UE, comprising: receiving a sidelink control information (SCI) retransmission for a third UE from the second UE; determining, based on the received SCI retransmission, first one or more resources to be used by the third UE for data retransmission; as well as Allocating resources for one or more subsequent transmissions excludes use of the second one or more resources for the SCI retransmission and the first one or more resources for the data retransmission by the third UE.

10. The method according to claim 9, wherein: The SCI retransmission and the data retransmission are associated with a second redundant RV; as well as The method further comprises: determining a third one or more resources to be used by the third UE for transmitting the SCI associated with the first RV and transmitting data associated with the first RV; as well as The third one or more resources are excluded from use for the one or more subsequent transmissions.

11. The method according to claim 10, wherein: Determining the third one or more resources includes determining the third one or more resources based on a preconfigured association between the first RV and the second RV.

12. The method according to claim 9, wherein: The SCI retransmission from the second UE is received in the subframe in the absence of a data transmission from the second UE in the subframe.

13. The method according to claim 9, wherein: The SCI retransmission from the second UE includes an indication that the SCI is an echo SCI of an SCI retransmitted by the third UE.

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