Sidelink feedback channel resource mapping in unlicensed spectrum

Abstract

Certain aspects of the present disclosure provide techniques for communicating using sidelink resources allocated in an unlicensed spectrum. A method that may be performed by a first UE includes receiving one or more transmissions from a second UE on one or more sidelink subchannels, the sidelink subchannels spanning one or more sets of resource blocks (RBs) of the unlicensed spectrum occupied by the second UE during a channel occupancy time (COT), and sending feedback information corresponding to the received one or more transmissions to the second UE on a feedback channel based on a mapping between the one or more sidelink subchannels and a feedback channel, the mapping restricting the feedback channel to at least the one or more sets of RBs of the unlicensed spectrum occupied by the second UE during the COT and one or more guard bands between the one or more sets of RBs.

Description

Technical Field

[0001] Aspects of the present disclosure relate to wireless communications and, more particularly, to techniques for sidelink feedback channel resource mapping in unlicensed spectrum. Background Art

[0002] Wireless communication systems are widely deployed to provide various telecommunication services, such as telephony, video, data, messaging, and broadcast. 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 these multiple-access systems include the Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) system, the LTE-Advanced (LTE-A) system, the Code Division Multiple Access (CDMA) system, the Time Division Multiple Access (TDMA) system, the Frequency Division Multiple Access (FDMA) system, the Orthogonal Frequency Division Multiple Access (OFDMA) system, the Single Carrier Frequency Division Multiple Access (SC-FDMA) system, and the Time Division Synchronous Code Division Multiple Access (TD-SCDMA) system, to name a few.

[0003] 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, country, regional, and even global level. New Radio (e.g., 5G NR) is an example of an emerging telecommunication standard. NR is a set of enhancements to the LTE mobile standard released by 3GPP. NR is designed to better support mobile broadband internet access by improving spectral efficiency, reducing costs, improving services, utilizing new spectrum, and better integrating with other open standards using OFDMA and cyclic prefixes (CP) on the downlink (DL) and uplink (UL). To this end, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0004] However, as the demand for mobile broadband access continues to increase, there is a need for further improvements to NR and LTE technologies. Preferably, these improvements should be applicable to other multi-access technologies and telecommunication standards that employ these technologies. Summary of the Invention

[0005] 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. Without limiting the scope of the present disclosure as expressed by the appended claims, some features will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled "Detailed Description," one will understand how the features of the present disclosure provide advantages, including improved mapping of sidelink feedback channel resources in unlicensed spectrum.

[0006] Certain aspects of the subject matter described in this disclosure may be implemented in a method for wireless communications by a first user equipment (UE). The method generally includes receiving one or more transmissions from a second UE on one or more sidelink subchannels, the sidelink subchannels spanning one or more resource block (RB) sets of unlicensed spectrum occupied by the second UE during a channel occupancy time (COT), and sending feedback information corresponding to the received one or more transmissions to the second UE on the feedback channel based on a mapping between the one or more sidelink subchannels and a feedback channel, the mapping restricting the feedback channel to at least the one or more RB sets of unlicensed spectrum occupied by the second UE during the COT and one or more guard bands between the one or more RB sets.

[0007] Certain aspects of the subject matter described in the present disclosure may be implemented in a first user equipment (UE) for wireless communication by the first user equipment (UE). The first UE generally includes: means for receiving one or more transmissions from a second UE on one or more sidelink subchannels, the one or more sidelink subchannels spanning one or more resource block (RB) sets of unlicensed spectrum occupied by the second UE during a channel occupancy time (COT), and means for sending feedback information corresponding to the received one or more transmissions to the second UE on a feedback channel based on a mapping between the one or more sidelink subchannels and a feedback channel, the mapping restricting the feedback channel to at least the one or more RB sets of unlicensed spectrum occupied by the second UE during the COT and one or more guard bands between the one or more RB sets.

[0008] Certain aspects of the subject matter described in the present disclosure can be implemented in a first user equipment (UE) for wireless communication. The first UE generally includes a memory; and a processor coupled to the memory, the memory and the processor being configured to: receive one or more transmissions from a second UE on one or more sidelink subchannels, the sidelink subchannels spanning one or more resource block (RB) sets of unlicensed spectrum occupied by the second UE during a channel occupancy time (COT), and send feedback information corresponding to the one or more received transmissions to the second UE on a feedback channel based on a mapping between the one or more sidelink subchannels and a feedback channel, the mapping restricting the feedback channel to at least the one or more RB sets of unlicensed spectrum occupied by the second UE during the COT and one or more guard bands between the one or more RB sets.

[0009] Certain aspects of the subject matter described in this disclosure may be implemented in a computer-readable medium for wireless communications. The medium includes instructions that, when executed by at least one processor of a first user equipment (UE), cause the at least one processor to: receive one or more transmissions from a second UE on one or more sidelink subchannels, the sidelink subchannels spanning one or more resource block (RB) sets of unlicensed spectrum occupied by the second UE during a channel occupancy time (COT), and send feedback information corresponding to the received one or more transmissions to the second UE on a feedback channel based on a mapping between the one or more sidelink subchannels and a feedback channel, the mapping restricting the feedback channel to at least the one or more RB sets of unlicensed spectrum occupied by the second UE during the COT and one or more guard bands between the one or more RB sets.

[0010] To accomplish the foregoing and related ends, one or more aspects include the features hereinafter fully described and particularly pointed out in the claims. The following description and accompanying drawings set forth in detail certain illustrative features of one or more aspects. However, these features are indicative of but some of the various ways in which the principles of the various aspects may be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] So that the manner in which the foregoing features of the present disclosure may be understood in detail, a more particular description of the foregoing briefly summarized aspects may be had by reference to various aspects, some of which are illustrated in the accompanying drawings. It should be noted, however, that the drawings illustrate only certain typical aspects of the disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.

[0012] Figure 1 is a block diagram conceptually illustrating an example wireless communication network in accordance with certain aspects of the present disclosure.

[0013] Figure 2 is a block diagram conceptually illustrating designs of an exemplary base station (BS) and user equipment (UE) in accordance with certain aspects of the present disclosure.

[0014] 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.

[0015] Figure 4A and Figure 4B A diagram of an example vehicle-to-everything (V2X) system is shown, in accordance with certain aspects of the present disclosure.

[0016] Figure 5A time-frequency grid of example resource pools for sidelink communications is illustrated in accordance with certain aspects of the present disclosure.

[0017] Figure 6 An example sidelink feedback channel resource pool mapping is illustrated in accordance with certain aspects of the present disclosure.

[0018] Figure 7 An example resource allocation in an unlicensed spectrum is shown in accordance with certain aspects of the present disclosure.

[0019] Figure 8 An exemplary mapping between one or more sidelink subchannels and a sidelink feedback channel is shown in accordance with certain aspects of the present disclosure.

[0020] Figure 9 An example sidelink feedback channel resource mapping based on resources allocated to a sidelink shared channel is illustrated, in accordance with certain aspects of the present disclosure.

[0021] Figure 10 Another example sidelink feedback channel resource mapping based on resources allocated to a sidelink shared channel, in accordance with certain aspects of the present disclosure, is illustrated.

[0022] Figure 11 An example sidelink feedback channel resource pool definition is illustrated in accordance with certain aspects of the present disclosure.

[0023] Figure 12 Another example sidelink feedback channel resource pool definition in accordance with certain aspects of the present disclosure is illustrated.

[0024] Figure 13 An example dynamic sidelink feedback channel resource pool definition is illustrated in accordance with certain aspects of the present disclosure.

[0025] Figure 14 An example dynamic sidelink feedback channel resource pool definition based on resources allocated to a sidelink shared channel is illustrated in accordance with certain aspects of the present disclosure.

[0026] Figure 15 An example dynamic sidelink feedback channel resource pool definition based on resources allocated to a sidelink control channel is illustrated in accordance with certain aspects of the present disclosure.

[0027] Figure 16 is a flow chart illustrating example operations for wireless communications by a UE in accordance with certain aspects of the present disclosure.

[0028] Figure 17A communications device according to aspects of the present disclosure is shown that may include various components configured to perform operations for the techniques disclosed herein.

[0029] 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

[0030] Various aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for sidelink feedback channel resource mapping in an unlicensed spectrum. Specifically, certain aspects relate to mapping one or more sidelink subchannels to a given sidelink feedback channel so as to restrict the sidelink feedback channel to a set of resource blocks (RBs) spanned by the sidelink subchannels.

[0031] In certain aspects, RBs may be allocated to sets (e.g., subbands), where each RB set includes multiple RBs. In addition, a guard band (e.g., a guard band within a cell) may be defined between each RB set. In certain aspects, a subchannel is mapped to and spans one or more RB sets, and sometimes even guard bands between RB sets. To utilize a particular subchannel, a UE may perform a listen-before-talk (LBT) procedure on one or more RB sets spanned by the subchannel, whereby the UE measures whether the energy level on the one or more RB sets is below a threshold. If the UE successfully determines that the energy level of one or more RB sets is below the threshold, it may begin transmitting on the particular subchannel, thereby reserving the one or more RB sets for a period of time known as the channel occupancy time (COT).

[0032] In certain aspects, a UE receiving a transmission is configured to provide feedback on a feedback channel, e.g., whether the transmission was successfully received and decoded (e.g., by sending an acknowledgment (ACK)), or whether the transmission was not successfully decoded (e.g., by sending a negative ACK (NACK)). To do this in unlicensed spectrum, the UE would typically need to perform an LBT procedure to ensure that resources are available for sending the ACK / NACK. However, in certain aspects, a UE sending a transmission to a receiving UE can share its reserved resources during the COT, so the receiving UE can send feedback without performing the LBT procedure. Accordingly, certain aspects herein relate to mapping a feedback channel used to provide feedback for transmissions made in a subchannel to a set of RBs (and optionally, guard bands) spanned by the subchannels that are reserved during the COT.

[0033] The following description provides examples of communicating in a communication system using sidelink resources allocated in an unlicensed spectrum and does not limit the scope, applicability, or examples set forth in the claims. The functions and arrangements of the elements discussed may be modified without departing from the scope of the present disclosure. Various examples may omit, replace, or add various processes or components as appropriate. For example, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Moreover, features described for some examples may be combined in other examples. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. Furthermore, the scope of the present disclosure is intended to encompass such apparatus or methods implemented with other structures, functions, or a combination of structures and functions in addition to or in place of the various aspects of the present disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects.

[0034] In general, any number of wireless networks can be deployed in a given geographic area. Each wireless network can support a specific radio access technology (RAT) and can operate on one or more frequencies. A RAT can also be referred to as a radio technology, air interface, etc. A frequency can also be referred to as a carrier, subcarrier, frequency channel, tone, subband, etc. Each frequency can support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs.

[0035] The techniques described herein can be used for various wireless networks and radio technologies. Although various aspects may be described herein using terms generally associated with 3G, 4G, and / or new radio (e.g., 5G NR) wireless technologies, various aspects of the present disclosure can be applied to other generation-based communication systems.

[0036] NR access can support various wireless communication services, such as enhanced mobile broadband (eMBB) for broadband (e.g., 80 MHz or higher), millimeter wave (mmW) for high carrier frequencies (e.g., 24 GHz to 53 GHz or higher), massive machine type communication (MTC) (mMTC) for non-backward compatible MTC technologies, and / or mission-critical 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 can dynamically configure beam directions. MIMO transmission with precoding can also be supported. 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 with up to 2 streams per UE can be supported. Up to 8 serving cells can support aggregation of multiple cells.

[0037] Figure 1 1 shows an exemplary wireless communication network 100 in which aspects of the present disclosure may be performed. For example, the wireless communication network 100 may be an NR system (e.g., a 5G NR network). Figure 1 As shown in , 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) 110 and / or user equipments (UEs) 120 in the wireless communication network 100 via one or more interfaces.

[0038] like Figure 1 As shown in , the wireless communication network 100 may include several BSs 110a-z (each BS is also referred to herein individually as BS 110 or collectively as BS 110) and other network entities. BS 110 may provide communication coverage for a specific geographic area (sometimes referred to as a "cell"), which may be stationary or may move according to the location of the mobile BS 110. In some examples, BSs 110 may be interconnected to each other and / or to one or more other BSs or network nodes (not shown) in the wireless communication network 100 using any suitable transport network via various types of backhaul interfaces (e.g., direct physical connections, wireless connections, virtual networks, etc.). Figure 1 In the example shown, Figure 1As shown, BSs 110a, 110b, and 110c may be macro BSs corresponding to macrocells 102a, 102b, and 102c, respectively. BS 110x may be a pico BS corresponding to picocell 102x. BSs 110y and 110z may be femto BSs corresponding to femtocells 102y and 102z, respectively. A BS may support one or more cells.

[0039] BS 110 in wireless communication network 100 communicates with UEs 120a-y (each UE is also referred to herein individually as UE 120 or collectively as UE 120). UEs 120 (e.g., 120x, 120y, etc.) may be dispersed throughout wireless communication network 100, and each UE 120 may be stationary or mobile. Wireless communication network 100 may also include relay stations (e.g., relay station 110r), also referred to as relay stations, etc., which receive transmissions of data and / or other information from upstream stations (e.g., BS 110a or UE 120r) and send transmissions of data and / or other information to downstream stations (e.g., UE 120 or BS 110), or relay transmissions between UEs 120 to facilitate communication between devices.

[0040] The network controller 130 may communicate with a set of BSs 110 and provide coordination and control (e.g., via 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 handover selection functions, etc.

[0041] According to certain aspects, UE 120 may be configured to send feedback information on a sidelink feedback channel in an unlicensed spectrum according to the sidelink feedback channel resource mapping described herein. Figure 1 As shown, each of UE 120a and UE 120b includes a respective sidelink feedback manager 122. The sidelink feedback manager 122 may be configured to perform Figure 16 The operations shown in and other operations described herein are for sending feedback information on a sidelink feedback channel in an unlicensed spectrum according to a sidelink feedback channel resource mapping.

[0042] Figure 2 It is shown (for example, Figure 1 1 and 2. In the wireless communication network 100 of FIG. 1 , a BS 110a and a UE 120a are shown as exemplary components, which may be used to implement aspects of the present disclosure.

[0043] At BS 110a, transmit processor 220 may receive data from data source 212 and control information from controller / processor 240. Control information may be used for the physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid ARQ indicator channel (PHICH), physical downlink control channel (PDCCH), group common PDCCH (GC PDCCH), etc. Data may be used for the 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 the exchange of control commands between wireless nodes. A MAC-CE may be carried in a shared channel, such as the physical downlink shared channel (PDSCH), the physical uplink shared channel (PUSCH), or the physical sidelink shared channel (PSSCH).

[0044] The processor 220 can process (e.g., encode and symbol map) data and control information to obtain data symbols and control symbols, respectively. The transmit processor 220 can also generate reference symbols, such as for the primary synchronization signal (PSS), secondary synchronization signal (SSS), PBCH demodulation reference signal (DMRS), and channel state information reference signal (CSI-RS). The 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 (if applicable) and can provide output symbol streams to the modulators (MODs) in the transceivers 232a-232t. Each modulator in the transceivers 232a-232t can process a corresponding 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 upconvert) 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.

[0045] At UE 120a, antennas 252a-252r can receive downlink signals from BS 110a and can provide received signals to demodulators (DEMODs) in transceivers 254a through 254r, respectively. Each demodulator in transceivers 254a through 254r can condition (e.g., filter, amplify, downconvert, and digitize) its respective received signal to obtain input samples. Each demodulator can further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 256 can obtain received symbols from all demodulators in transceivers 254a through 254r, perform MIMO detection on the received symbols (if applicable), and provide detected symbols. A receive processor 258 can process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UE 120a to a data sink 260, and provide decoded control information to a controller / processor 280.

[0046] On the uplink, at the UE 120a, a transmit processor 264 may receive and process data (e.g., for a physical uplink shared channel (PUSCH)) from a data source 262 and control information (e.g., for a physical uplink control channel (PUCCH)) from the controller / processor 280. 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 the modulators in the transceivers 254a-254r (e.g., for SC-FDM, etc.), and transmitted to the BS 110a. At BS 110a, the uplink signal from UE 120a may be received by antenna 234, processed by modulators 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 the decoded data to a data sink 239 and the decoded control information to a controller / processor 240.

[0047] 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.

[0048] The antennas 252, processors 266, 258, 264, and / or controller / processor 280 of the UE 120a, and / or the antennas 234, processors 220, 230, 238, and / or controller / processor 240 of the BS 110a may be operable to perform the various techniques and methods described herein. Figure 2 As shown, the controller / processor 280 of the UE 120a has a sidelink feedback manager 122, which can be configured to perform Figure 16 The operations shown in FIG. 1 and other operations disclosed herein are for transmitting feedback information on a sidelink feedback channel in an unlicensed spectrum according to a sidelink feedback channel resource mapping. Although shown at the controller / processor, other components of the UE 120 a and the BS 110 a may be used to perform the operations described herein.

[0049] NR can utilize orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) on both the uplink and downlink. NR can support half-duplex operation using time division duplexing (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 15 kHz, and other SCSs (e.g., 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc.) can be defined for the basic SCS.

[0050] Figure 33 is a diagram showing an example of a 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 can have a predetermined duration (e.g., 10 ms) and can be divided into 10 subframes, each 1 ms and having indices 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 periods in each slot can be assigned an index. A mini-slot, which can be referred to as a subslot structure, refers to a transmission time interval with a duration less than one slot (e.g., 2, 3, or 4 symbols). Each symbol in a slot can indicate a link direction (e.g., DL, UL, or flexible) for data transmission, and the link direction for 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.

[0051] In NR, synchronization signal blocks (SSBs) are transmitted. In certain aspects, SSBs may be transmitted in bursts, where each SSB in the burst corresponds to a different beam direction for UE-side beam management (e.g., including beam selection and / or beam refinement). SSBs include PSS, SSS, and two symbols of PBCH. They may be transmitted at fixed slot locations (e.g., Figure 3 The SSB is sent in symbols 0-3 shown in . The UE can use PSS and SSS for cell search and acquisition. PSS can provide half-frame timing, and SS can provide CP length and frame timing. PSS and SSS can provide cell identity. PBCH carries some basic system information, such as downlink system bandwidth, timing information within the radio frame, SS burst set periodicity, system frame number, etc. SSB can be organized into SS bursts to support beam scanning. Other system information such as remaining minimum system information (RMSI), system information block (SIB), other system information (OSI) can be sent on the physical downlink shared channel (PDSCH) in certain subframes. For millimeter waves, SSB can be sent up to 64 times, for example, with up to 64 different beam directions. Multiple transmissions of SSB are called SS burst sets. SSBs in one SS burst set can be sent in the same frequency region, while SSBs in different SS burst sets can be sent at different frequency regions.

[0052] Exemplary Sidelink Communications

[0053] In some examples, two or more slave entities (e.g., UE 120) can communicate with each other using sidelink signals. Practical applications of such sidelink communications may include public safety, nearby services, UE-to-network relaying, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical grids, and / or various other suitable applications. Generally, a sidelink signal may refer to a signal transmitted from one slave entity (e.g., UE 120a) to another slave entity (e.g., another UE 120) without relaying the communication through a scheduling entity (e.g., UE 120 or BS 110), even though the scheduling entity may be used for scheduling and / or control purposes. In some examples, the sidelink signals may be transmitted using licensed spectrum (unlike wireless local area networks, which typically use unlicensed spectrum). An example for sidelink communication is PC5, for example, as used in V2V, LTE, and / or NR.

[0054] Various sidelink channels can be used for sidelink communications, including the Physical Sidelink Discovery Channel (PSDCH), the Physical Sidelink Control Channel (PSCCH), the Physical Sidelink Shared Channel (PSSCH), and the Physical Sidelink Feedback Channel (PSFCH). The PSDCH can carry discovery expressions that enable nearby devices to discover each other. The PSCCH can carry control signaling, such as sidelink resource configuration, resource reservation, and other parameters for data transmission, while the PSSCH can carry data transmission. The PSFCH can carry feedback corresponding to the transmission on the PSSCH, such as acknowledgment (ACK) and / or negative ACK (NACK) information. In some systems (e.g., NR Release 16), two-stage SCI can be supported. The two-stage SCI can include a first-stage SCI (SCI-1) and a second-stage SCI (e.g., SCI-2). SCI-1 can include resource reservation and allocation information, information that can be used to decode SCI-2, and so on. SCI-2 can include information that can be used to decode data and determine whether the UE is the intended recipient of the transmission. SCI-1 and / or SCI-2 may be transmitted through the PSCCH.

[0055] Figure 4A and Figure 4B A diagram of an exemplary V2X system according to some aspects of the present disclosure is shown. For example, Figure 4A and Figure 4B The vehicles shown in can communicate via a sidelink channel and can relay sidelink transmissions as described herein.

[0056] Figure 4A and Figure 4B The V2X system provided in [1] provides two complementary transmission modes. Figure 4AThe first transmission mode (also referred to as Mode 4), shown by way of example in FIG, involves direct communication (e.g. also referred to as sidelink communication) between participants that are close to each other in a local area. Figure 4B The second transmission mode (also referred to as Mode 3) shown by way of example in FIG. 5 involves network communication through the network, which may be achieved through a Uu interface (eg, a wireless communication interface between a Radio Access Network (RAN) and a UE).

[0057] refer to Figure 4A , a V2X system 400 (e.g., including vehicle-to-vehicle (V2V) communications) is shown 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 a person (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 a similar manner, communication can be made from vehicle 402 to other highway components (e.g., highway component 410), such as traffic signals or signs (V2I) through a PC5 interface 412. Figure 4A Each communication link shown in can enable bidirectional communication between elements, so each element can be both a transmitter and a receiver of information. The V2X system 400 can be a self-managed system that is implemented without the assistance of a network entity. Because no network service interruption occurs during handover operations of a moving vehicle, the self-managed system can achieve improved spectrum efficiency, reduced costs, and increased reliability. The V2X system can be configured to operate in licensed or unlicensed spectrum, so any vehicle equipped with the system can access common frequencies and share information. This coordinated / shared spectrum operation allows for safe and reliable operation.

[0058] Figure 4B A V2X system 450 is shown for communicating between a vehicle 452 and a vehicle 454 via a network entity 456. These network communications can occur through discrete nodes such as a base station (e.g., base station 110a), which transmit information to (e.g., relay information between) vehicles 452 and 454 and receive information from vehicles 452 and 454. For example, network communications via vehicle-to-network (V2N) links 458 and 460 can be used for long-range communication between vehicles, such as for communicating a car accident some distance ahead along a road or highway. Wireless nodes can send other types of communications to vehicles, such as traffic flow conditions, road hazard warnings, environmental / weather reports, and service station availability. This data can be obtained from a cloud-based sharing service.

[0059] Roadside units (RSUs) may be employed. RSUs may be used for V2I communications. In some examples, RSUs may act as forwarding nodes to extend coverage for 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 divided into UE-type RSUs and micro-node B-type RSUs. Micro-node B-type RSUs have similar functionality to macro eNBs or gNBs. Micro-node B-type RSUs may employ a 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 a centralized resource allocation mechanism to allow efficient resource utilization. Critical information (e.g., traffic conditions, weather conditions, congestion statistics, sensor data, etc.) may be broadcast to UEs in the coverage area. Repeaters may rebroadcast critical information received from some UEs. UE-type RSUs may be reliable synchronization sources.

[0060] Example sidelink feedback channel resource mapping in unlicensed spectrum

[0061] When communicating on the sidelink, the UE can use resources selected from a resource pool. The resource pool can be defined as a contiguous number of resource blocks (RBs) in the frequency domain, with subchannels as the unit. In other words, a resource pool can consist of multiple contiguous RBs in frequency. Specifically, a subchannel can be defined as one or more RBs (e.g., contiguous), and a resource pool can be defined as one or more subchannels.

[0062] Figure 5 A time-frequency grid depicting an exemplary resource pool for sidelink communications according to certain aspects presented herein is shown. As can be seen, three different resource pools (e.g., 502, 504, and 506) are shown. Resource pool 502 can be composed of two subchannels 508 (e.g., allocated to a physical sidelink control channel (PSCCH) and a physical sidelink shared channel (PSSCH)) and 510 (e.g., allocated to a PSSCH), each of which includes a set of contiguous RBs spanning different frequencies. As shown, resource pools 504 and 506 can each include four subchannels spanning different frequency bands.

[0063] In some cases, the sidelink resource pool can be defined by several parameters, such as parameters sl-StartRB-Subchannel, sl-SubchannelSize, and sl-NumSubchannel, although it should be noted that they can be referred to in any suitable manner. The parameter sl-StartRB-Subchannel can define the first RB of the lowest indexed subchannel of the resource pool. For example, referring to resource pool 502, the parameter sl-StartRB-Subchannel can specify the first RB of subchannel 508. In addition, the parameter sl-SubchannelSize can define the number of RBs for each subchannel in the resource pool, and the parameter sl-NumSubchannel can define the number of subchannels in the resource pool. Thus, for example, referring to resource pool 502, the parameter sl-NumSubchannel can define resource pool 502 as including two subchannels (e.g., 508 and 510), and the parameter sl-SubchannelSize can define that each of subchannels 508 and 510 includes 10 RBs to 100 RBs.

[0064] In some cases, within each subchannel, a sidelink control channel (e.g., a physical sidelink control channel (PSCCH)) may occupy a first number of RBs (e.g., where the number is a value of a parameter sl-FreqResourcePSCCH) and a first number of symbols (e.g., where the number is a value of a parameter sl-TimeResourcePSCCH) allocated to a first subchannel of a sidelink shared data channel (e.g., a physical sidelink shared channel (PSSCH)). In some cases, control information included in the PSCCH may allocate the number of subchannels that may be included in the PSSCH, starting from the current subchannel in which the PSCCH is transmitted.

[0065] In some cases, the UE may need to send feedback information to indicate whether certain transmissions on the PSSCH and / or PSCCH have been successfully received. The feedback information may include an acknowledgment (ACK) for successfully received and decoded transmissions and / or a negative ACK (NACK) for unsuccessfully decoded transmissions, corresponding to the transmissions on the PSSCH / PSCCH. In some cases, the feedback information may be sent on a feedback channel, referred to as the Physical Sidelink Feedback Channel (PSFCH). In order to send feedback information on the PSFCH, a resource set may be selected from a non-dedicated PSFCH resource pool.

[0066] Figure 6An exemplary PSFCH resource pool 602 is shown in FIG. As shown, the PSFCH resource pool 602 can be divided into a set of separate sub-resource pools 604, each corresponding to a different sidelink sub-channel spanning a different time slot. Although certain aspects are described in terms of time slots, other suitable durations can similarly be used. For example, Figure 6 As shown, a total of eight subchannels across two time slots can be used to carry PSSCH / PSCCH information. Therefore, the PSFCH resource pool 602 can be divided into eight different sub-resource pools 604 corresponding to the eight different subchannels across two time slots for carrying feedback information. Each sub-resource pool 604 can include multiple resources (e.g., RBs), and the UE can select a resource 606 from the multiple resources within the sub-resource pool 604 to send feedback information for each sub-channel.

[0067] The UE may determine a PSFCH resource pool and select resources for sending feedback information based on a number of parameters. Although certain names are given to these parameters, it should be noted that they may be referred to in any suitable manner. For example, in some cases, the UE may be configured with a parameter periodPSFCHresource that may indicate a period in a time slot in the resource pool that is used for PSFCH transmission. In some cases, the supported time periods are 0 / 1 / 2 / 4, where 0 means no PSFCH. In some aspects, the PSFCH transmission timing may be determined as the first time slot with PSFCH resources after receiving the PSSCH and after MinTimeGapPSFCH (e.g., a time value) after the PSSCH. In some cases, the parameter periodPSFCHresource may be configured with a parameter periodPSFCHresource that may indicate a period in a time slot in the resource pool that is used for PSFCH transmission. In some cases, the supported time periods are 0 / 1 / 2 / 4, where 0 means no PSFCH. In some aspects, the PSFCH transmission timing may be determined as the first time slot with PSFCH resources after receiving the PSSCH and after MinTimeGapPSFCH (e.g., a time value) after the PSSCH. A PRB set for PSFCH in a time slot may be defined. As discussed above, the PRB set may be defined in a time slot. (e.g., the number of PSSCH slots corresponding to the PSFCH slot) and N subch PSSCH (e.g., the number of PSSCH subchannels). Thus, for PSFCH, each subchannel / time slot can have In some cases, the mapping from PSSCH resources to PSF CHPRBs may be performed first in time.

[0068] The size of the PSFCH resource pool can be adjusted based on To define, where is the number of cyclic shift (CS) pairs per RB configuration in the resource pool (e.g., where the pair is for 1-bit ACK / NACK). is 1 or Indicates whether the PSFCH resource pool is shared for the subchannels in a PSSCH slot. In some cases, within the pool, PSFCH resources may be indexed by PRB and then by CS.

[0069] In some cases, the UE may ID +M ID )mod Determine the PSFCH resource used to send feedback information, where P ID is the physical source ID of the sidelink control information (SCI) 0-2 from the PSSCH, and M ID M is 0 or identifies the UE receiving the PSSCH. In certain aspects, for unicast or NAK-based transmissions, M ID = 0 and the UE may send ACK or NAK only on the resources in the pool that depend on the source ID.For multicast, in certain aspects the destination ID may be used to select one resource in the resource pool for sending feedback information.

[0070] In some cases, it may be advantageous to perform sidelink communications using wideband channel operation within the unlicensed spectrum in order to take advantage of globally available "free" spectrum. However, the resource allocation in the unlicensed spectrum may differ from the resource allocation for sidelink communications.

[0071] For example, for operation in unlicensed spectrum, due to potential coexistence issues with WiFi, channel access in unlicensed spectrum can be divided into multiple 20 MHz sub-bands even when the system is operating in wideband mode (e.g., multiples of 20 MHz). To access a specific 20 MHz sub-band, a wireless device (e.g., a UE) may first perform a listen-before-talk (LBT) procedure to determine whether the 20 MHz sub-band is available for use by the wireless device. If the wireless device senses that no other transmissions have occurred in the 20 MHz sub-band for a period of time, indicating that the 20 MHz sub-band is idle, then the 20 MHz sub-band is available for use. In some cases, the wireless device may infer that the 20 MHz sub-band is idle by sensing the energy level on the 20 MHz sub-band. If the energy level of the 20 MHz sub-band is below a threshold, the wireless device may infer that the 20 MHz sub-band is available for use. However, if the LBT procedure fails (e.g., the energy level of the 20 MHz sub-band is greater than a threshold), the wireless device may try another 20 MHz bandwidth portion. It should be noted that the 20 MHz sub-band is just an example and that the sub-bands may have different bandwidths.

[0072] To support this type of operation, for example in 5G New Radio - Unlicensed (NR-U), an intra-cell guard band is introduced to define a guard band between each (e.g., approximately 20 MHz) sub-band. The passband between two adjacent intra-cell guard bands may be referred to as an "RB set," which is approximately 20 MHz. For example, Figure 7 As shown, the unlicensed spectrum can be divided into a plurality of RB sets (eg, each RB set spanning a bandwidth of approximately 20 MHz), including a plurality of RBs 702. Figure 7 As shown in the example shown in , the unlicensed spectrum can be divided into four different RB sets, including RB set 0, RB set 1, RB set 2, and RB set 3, and an intra-cell guard band 704 can be inserted between each RB set. It should be noted that there can be a greater or lesser number of RB sets, and they can have a greater or lesser bandwidth / number of RBs. As described above, in order to communicate using the unlicensed spectrum, the wireless device can perform an LBT process to sense which RB sets are available for communication. Figure 7 As shown, RB set 1 and RB set 2 have passed the LBT process and are available for use / allocation by the wireless device.

[0073] In some cases, (e.g., NR-U) systems can support both continuous and staggered uplink resource allocation while complying with the rules. In staggered uplink resource allocation, the basic unit of resource allocation for NR unlicensed channels is an interlace, e.g., Figure 7 As shown, the interlace is composed of ten equally spaced RBs 702 for a 15 kHz subcarrier spacing within a 20 MHz frequency bandwidth (e.g., an RB set). In certain aspects, for RBs that belong to the assigned interlace set but fall within the intra-cell guard band, these RBs are only allocated if the RB sets on both sides are allocated. Furthermore, in some cases, if the RB sets on both sides of the intra-cell guard band are allocated to a wireless device (e.g., a UE), the UE may transmit in the intra-cell guard band 704. Similarly, in some cases, if the UE is a high-capability UE, the UE may also receive transmissions in the intra-cell guard band 704. However, if the UE is a low-capability UE, the UE may only receive transmissions within the RB set and may not receive transmissions in the intra-cell guard band 704. In some cases, the UE may send information to the base station indicating the UE's capabilities. If the capability information indicates that the UE is a low-capability UE, the base station may avoid scheduling the physical data shared channel (PDSCH) on the guard band RBs to the low-capability UE.

[0074] As described above, in order to take advantage of globally available "free" spectrum, it is beneficial to perform sidelink communications using wideband channel operation within the unlicensed spectrum. However, a potential problem with performing sidelink communications in the unlicensed spectrum is related to the way the sidelink subchannels are defined and the way the RB sets are defined in the unlicensed spectrum. For example, as described above, the subchannels in the sidelink can be defined contiguously without any spacing between different subchannels. This creates a problem when these contiguously defined subchannels are mapped to the RB sets of the unlicensed band, which includes an intra-cell guard band located between these RB sets. For example, if the sidelink subchannels are defined in a traditional manner, where the subchannels are contiguous, some sidelink subchannels may partially overlap with the intra-cell guard band in the unlicensed spectrum, which may result in these sidelink subchannels in the unlicensed spectrum being unusable by certain UEs (e.g., low-capability UEs). Therefore, in some cases, to help alleviate these problems, the sidelink subchannels can be confined to the RB sets of the unlicensed spectrum so that no sidelink subchannel overlaps the intra-cell guard band. Therefore, by restricting the sidelink subchannels to the set of RBs that accommodate the unlicensed spectrum, the usage of each sidelink subchannel depends only on the LBT of the set of RBs to which the sidelink subchannel is restricted.

[0075] In addition, in some cases (e.g., NR-U), the concept of channel occupancy time (COT) sharing has been introduced, whereby the COT on a particular subband (e.g., a set of RBs) obtained by a transmitter device (e.g., UE) through a LBT process on that subband can be shared with another device (e.g., UE). For example, the COT for a band / subband can specify a time interval during which the transmitter device can continuously transmit on the band before yielding the channel (e.g., ceasing to transmit on the band for a period of time to allow another device to potentially perform LBT and begin transmitting on the band).

[0076] In some cases, the COT for a frequency band may be specified to be limited to a specific time interval (e.g., 2 to 10 milliseconds), depending on the market, frequency band, technical considerations (e.g., signal priority), and the duration of the corresponding LBT process (generally, the longer the LBT process duration, the larger the corresponding COT). In some cases, it may be desirable to share the COT with multiple UEs. In COT sharing, the principle is that one UE obtains a COT by performing LBT (e.g., Type 4 (Cat4) LBT), while other UEs can share the same COT (i.e., initiate transmissions without performing LBT) until the COT duration expires. COT sharing can take at least two forms: TDM-based COT sharing, in which the COT is shared through time multiplexing (e.g., UEs transmit one after another until the COT duration expires), and FDM-based COT sharing, in which the COT is shared through frequency multiplexing (e.g., UEs transmit simultaneously on different subchannels of the frequency band to which the COT applies). In some cases, these two types of COT sharing can also be combined.

[0077] This concept of COT sharing can also be applied to feedback information transmission on the sidelink feedback channel. For example, in some cases, after performing LBT to obtain the COT on a specific set of RBs and sending PSCCH / PSSCH, the transmitting node (e.g., UE) can share the COT with the responding node, allowing the responding node to use the same COT to send feedback information in the PSFCH. However, given the current legacy mapping of PSCCH / PSSCH to PSFCH, the PSFCH may be located in a different subband, preventing COT sharing (e.g., because the subband used for PSFCH may not be the subband reserved for COT).

[0078] Thus, aspects of the present disclosure provide techniques that allow feedback information to be transmitted on a sidelink feedback channel using COT sharing. In some cases, these techniques may include taking into account the definition of RB sets when configuring a PSFCH resource pool for sending feedback information corresponding to a PSCCH / PSSCH. For example, in some cases, the mapping of PSCCH / PSSCH to PSFCH may be updated so that the PSFCH for PSCCH / PSSCH is restricted to the same subband (e.g., one or more RB sets) as the PSCCH / PSSCH. More generally, in some cases, the mapping may restrict the PSFCH to one or more RB sets of the unlicensed spectrum occupied by the second UE.

[0079] Accordingly, in some cases, a technique for allowing transmission of feedback information on a sidelink feedback channel using COT sharing may include a first UE receiving one or more transmissions from a second UE on one or more sidelink subchannels spanning one or more RB sets of unlicensed spectrum occupied by the second UE in the COT, and sending feedback information corresponding to the received one or more transmissions to the second UE on the feedback channel based on a mapping between the one or more sidelink subchannels and the feedback channel, wherein the mapping limits the feedback channel to at least the one or more RB sets of unlicensed spectrum occupied by the second UE in the COT and one or more guard bands between the one or more RB sets.

[0080] Figure 8 An example of a mapping between one or more sidelink subchannels and a sidelink feedback channel according to certain aspects presented herein is provided. As shown, Figure 8 The mapping shown in the figure can restrict the feedback channel (e.g., PSFCH) to the same RB set in which the PSCCH / PSSCH is transmitted. For example, as shown in the figure, multiple RB sets (e.g., RB set 0 and RB set 1) can be restricted to the unlicensed spectrum. In addition, as shown in the figure, in order to prevent the sidelink subchannel from overlapping with the guard band within the cell, the sidelink subchannel can be completely restricted to the defined RB set. For example, as shown in the figure, a first sidelink subchannel set (e.g., sidelink subchannels 0-3) can be restricted to RB set 0, while a second sidelink subchannel set (e.g., sidelink subchannels 4-6) can be restricted to RB set 1.

[0081] In some cases, the second UE discussed above (e.g., the transmitting / initiating UE) may perform an LBT procedure to reserve a set of RBs for the duration of the COT in order to transmit PSCCH / PSSCH to the first UE discussed above (e.g., the receiving / responding UE) using one or more sidelink subchannels defined within the reserved / occupied set of RBs. To allow transmission of feedback information on a PSFCH corresponding to a received PSCCH / PSSCH via COT sharing, a PSFCH resource pool / cluster may be mapped to one or more sidelink subchannels on which the PSCCH / PSSCH is received such that the PSFCH is restricted to the same set of RBs occupied by the transmitting device at the COT.

[0082] In some cases, as shown, the mapping between one or more sidelink subchannels and the PSFCH may define a separate resource pool for the PSFCH for each of the one or more RB sets occupied by the second UE. Figure 8As shown, if the second UE occupies RB set 0 and the PSCCH / PSSCH is received on one of the sidelink subchannels defined within RB set 0 (e.g., sidelink subchannels 0-3), the PSFCH resource pool 802 for transmitting feedback information corresponding to the PSCCH / PSSCH can be limited to RB set 0. Similarly, as shown, if the second UE occupies RB set 1 and the PSCCH / PSSCH is received on one of the sidelink subchannels defined within RB set 1 (e.g., sidelink subchannels 4-6), the PSFCH resource pool 804 for transmitting feedback information corresponding to the PSCCH / PSSCH can be limited to RB set 1. Therefore, by limiting the PSFCH resource pool to the RB set in which the PSCCH / PSSCH is received, it can be ensured that the first UE can share the same COT with the second UE because the feedback information will be sent by the first UE within the same RB set occupied by the second UE.

[0083] In some cases, there may be different ways to associate the PSCCH / PSSCH with the PSFCH. For example, in some cases, a per-RB set PSCCH / PSSCH subchannel-to-PSFCH resource mapping can be introduced. This approach is essentially equivalent to updating the traditional subchannel-to-PSFCH mapping to map the subchannels within an RB set to the PSFCH resources of the same RB set. For example, in this case, the mapping can define a separate resource pool for the feedback channel of each RB set occupied by the second UE.

[0084] In other cases, a physical resource indicator (PRI) type indication in the sidelink control information (SCI) (e.g., SCI1 or SCI2) can be used to indicate the PSFCH resource pool. Thus, in some cases, a first UE can receive a PRI from a second UE in an SCI that grants the COT occupied by the second UE to the first UE. The first UE can then determine the resource pool for sending feedback information on the PSFCH based on the PRI. In some cases, the PSFCH resource pool to be addressed by the PRI can depend on the LBT result at the second UE. Additionally, in some cases, the PSFCH resource set can be identified by the Frequency Domain Resource Allocation (FDRA) field in SCI1 (e.g., so the receiving UE knows which RB sets pass LBT).

[0085] In some cases, there may be different ways to implement the PRI indication to indicate the PSFCH resource pool. For example, in some cases, the PRI addressable space of the PSFCH resource pool may be restricted to the same RB set as the RB set carrying the PSCCH. For example, in this case, the second UE may transmit the PSCCH in one or more sidelink subchannels of one or more RB sets, and based on the PRI, the mapping between the one or more sidelink subchannels and the feedback channel (e.g., PSFCH) may restrict the feedback channel to the one or more RB sets occupied by / carrying the PSCCH.

[0086] In other cases, the PRI addressable space of the PSFCH resource pool may be restricted to a set of RBs that are (e.g., partially) occupied by the PSSCH (e.g., a set of RBs that the LBT should pass through to support PSSCH transmission). For example, in this case, the second UE may transmit the PSSCH in one or more sidelink subchannels of one or more RB sets, and based on the PRI, the mapping between the one or more sidelink subchannels and the feedback channel (e.g., PSFCH) may restrict the feedback channel to one or more RB sets occupied by / carrying the PSSCH. Figure 9 An example of this mapping is shown in .

[0087] For example, Figure 9 As shown, the PSSCH 902 can be sent by the second UE within the resources of RB set 0. Therefore, since the PSSCH 902 is sent in RB set 0, the resource pool 904 for the feedback channel (e.g., PSFCH) can also be limited to RB set 0, which can be indicated to the first UE via the PRI in the SCI. The first UE can use the PRI to determine the resource pool for the PSFCH and can send feedback information based on the determined resource pool.

[0088] However, in some cases, the PSSCH may span at least two of the one or more RB sets, such as Figure 10 For example, Figure 10As shown, the second UE may transmit PSSCH across multiple RB sets (e.g., RB set 0 and RB set 1). Therefore, since the PSSCH spans two different RB sets in this case, two different PSFCHs may be defined for transmitting feedback information corresponding to the PSSCH. For example, as shown, in this case, a first PSFCH resource pool 1004 may be defined for RB set 0, and a second PSFCH resource pool 1006 may be defined for RB set 1. For example, based on the PRI received in the SCI, the UE may determine which PSFCH resource pool to use to transmit feedback information corresponding to the PSSCH. For example, in this case, since the PSSCH spans two RB sets (RB set 0 and RB set 1), the PRI may indicate a PSFCH resource pool (e.g., the first PSFCH resource pool 1004 or the second PSFCH resource pool 1006) of one of the two RB sets for transmitting feedback information on a feedback channel (e.g., PSFCH).

[0089] In some cases, when PSSCH is transmitted across multiple RB sets, the PSFCH resource pool corresponding to the PSSCH may be defined in different ways. In some aspects, such definition is configured at the UE using RRC signaling from the base station. For example, in Figure 11 In an example shown in , the PSFCH resource pools can be defined by the starting RB and the number of RBs for each PSFCH resource pool. In this case, the base station (e.g., gNB) can be responsible for limiting each PSFCH resource pool / cluster to a set of RBs. For example, Figure 11 As shown in , a PSFCH resource pool may be defined for each RB set in which a PSSCH is transmitted, e.g., a PSFCH resource pool 1104 is defined for RB set 0, and a PSFCH resource pool 1106 is defined for RB set 1. As noted, the PSFCH resource pool 1104 and the PSFCH resource pool 1106 may be defined based on the starting RB of each PSFCH resource pool within its respective RB set and the number of RBs included in the resource pool within the RB set.

[0090] Therefore, in some cases, when PSSCH is transmitted across multiple RB sets, the first UE may determine a resource pool for each of the one or more RB sets. Figure 11, the first UE may determine a PSFCH resource pool 1104 for RB set 0 and a PSFCH resource pool 1106 for RB set 1. In some cases, as described above, the first UE may determine PSFCH resource pool 1104 and PSFCH resource pool 1106 based at least in part on an indication of a starting RB for each PSFCH resource pool within its respective RB set and a number of RBs included in the PSFCH resource pool within the RB set.

[0091] In other cases, when PSSCH is transmitted across multiple RB sets, the PSFCH resource pool corresponding to the PSSCH can be defined by removing one or more RBs within the guard band from the RBs included in the larger PSFCH resource pool. Figure 12 As illustrated, larger PSFCH resource pool 1202 can be configured to span multiple RB sets, such as RB set 0 and RB set 1. In some cases, larger PSFCH resource pool 1202 can be configured by indicating a starting RB for larger PSFCH resource pool 1202 and a number of RBs included in larger PSFCH resource pool 1202. Subsequently, PSFCH resource pools for RB set 0 and RB set 1 can be defined by removing resources (e.g., RBs) within guard band 1204 disposed between RB set 0 and RB set 1. For example, by removing RBs within guard band 1204 from larger PSFCH resource pool 1202, a first PSFCH resource pool 1206 can be defined for RB set 0, and a second PSFCH resource pool 1208 can be defined for RB set 1. As shown, first PSFCH resource pool 1206 can be larger than second PSFCH resource pool 1208.

[0092] Therefore, in this case, when a larger PSFCH resource pool is configured, the first UE can determine the PSFCH resource pool for the respective RB sets by first determining the larger PSFCH resource pool 1202 spanning RB sets 0 and 1, which can be occupied by the second UE at the COT. In some cases, the first UE can determine the larger PSFCH resource pool 1202 based on an indication of the starting RB of the larger PSFCH resource pool 1202 and the number of RBs included in the larger PSFCH resource pool 1202. Thereafter, the first UE can determine a first PSFCH resource pool 1206 for RB set 0 and a second PSFCH resource pool 1208 for RB set 1 by removing RBs within a guard band 1204 (e.g., arranged between RB set 0 and RB set 1) from the RBs included in the larger PSFCH resource pool 1202. Thereafter, the UE can send feedback information on resources in at least one of the first PSFCH resource pool 1206 or the second PSFCH resource pool 1208. In some cases, as described above, the UE may determine on which of the first PSFCH resource pool 1206 or the second PSFCH resource pool 1208 to send feedback information based on, for example, the PRI.

[0093] In some cases, the PSFCH resource pool can be dynamic and based on the available RB sets. For example, in this case, a larger PSFCH resource pool can be configured that spans multiple RB sets and intra-cell guard bands. In this case, for each COT, the actual PSFCH resource pool that the first UE can use to send feedback information can be determined as a subset of the PSFCH resources from the larger PSFCH resource pool. In some cases, the actual PSFCH resource pool used to send feedback information can be dynamically determined in different ways.

[0094] For example, in some cases, the actual PSFCH resource pool may be based on the number of available RB sets, such as Figure 13 For example, Figure 13As shown, a larger PSFCH resource pool can be configured, spanning multiple RB sets and intra-cell protection bands, such as RB sets 0-3. Here, the actual PSFCH resource pool can be limited to the RB sets occupied by the second UE (e.g., and the protection bands between these RB sets). In this case, the second UE can provide an indication to the first UE of the following: the RB sets that can be used to carry feedback information on the PSFCH in the COT occupied by the second UE. In some cases, RB set availability information can be provided in the SCI (SCI1 or SCI2) sent by the second UE. Given the RB set availability information, the first UE can determine a sub-resource pool for the PSFCH in the COT and use the sub-resource pool for PSFCH hashing.

[0095] For example, in some cases, the first UE may determine a configured larger PSFCH resource pool 1302 for sending feedback information. In some cases, the configured larger PSFCH resource pool 1302 may be limited to at least the one or more RB sets of the unlicensed spectrum occupied by the second UE at the COT and one or more guard bands between the one or more RB sets. Thereafter, the first UE may receive information indicating one or more available RB sets of the one or more RB sets occupied by the second UE at the COT. In some cases, such as Figure 13 As shown in , this information may indicate that RB sets 0-2 are available. In some cases, the first UE may receive information indicating one or more available RB sets in sidelink control information from the second UE. Thereafter, the first UE may determine a sub-resource pool 1304 from the larger PSFCH resource pool 1302, which is used to send feedback information on the feedback channel at the COT based on the information indicating the one or more available RB sets. For example, as shown in the figure, in this case, the sub-resource pool 1304 may span RB sets 0-2.

[0096] In some cases, the sub-resource pool used for PSFCH may be limited to the set of RBs occupied by PSSCH (e.g., and the guard bands between these RB sets). Figure 14As shown, the second UE may transmit PSSCH 1402 across multiple RB sets (e.g., RB sets 0-2). Thus, in this case, the sub-resource pool 1404 for PSFCH may be limited to the RB sets occupied by PSSCH (e.g., and the guard bands between these RB sets). For example, as shown, the sub-resource pool 1404 for PSFCH may be limited to RB sets 0-2 because PSSCH is transmitted in RB sets 0-2. In some cases, the second UE may provide PSSCH FDRA to the first UE. Thus, in conjunction with the definition of RB sets, the first UE may be able to determine the RB set that passes LBT at the second UE (e.g., the RB set occupied by the second UE), and, given the occupied RB set information, the first UE may identify the sub-resource pool 1404 for PSFCH at that COT and use the sub-resource pool 1404 for PSFCH hashing.

[0097] For example, in some cases, the first UE may determine at least one RB set including resources allocated for the PSSCH from one or more RB sets of unlicensed spectrum occupied by the second UE in the COT. For example, in some cases, the first UE may determine that RB sets 0-2 may include resources allocated for the PSSCH 1402. Thereafter, the first UE may determine a sub-resource pool 1404 for transmitting feedback information on a feedback channel in the COT from a configured larger resource pool 1406 spanning RB sets 0-3. In some cases, the first UE may determine the sub-resource pool 1404 based at least in part on at least one RB set (e.g., RB sets 0-2) including resources allocated for the PSSCH 1402. Thus, as shown, in this case, the sub-resource pool 1404 may be limited to at least one RB set (e.g., RB sets 0-2) including resources allocated for the PSSCH 1402.

[0098] In some cases, the sub-resource pool used for PSFCH can be restricted to the set of RBs occupied by PSCCH. Figure 15 As shown in FIG, the second UE may transmit PSCCH 1502 in an RB set (e.g., RB set 0). Thus, in this case, the sub-resource pool 1504 for PSFCH may be limited to the RB set occupied by PSCCH. For example, as shown, the sub-resource pool 1504 for PSFCH may be limited to RB set 0 because PSCCH is transmitted in RB set 0. Thus, the UE may receive PSCCH in a sidelink subchannel in RB set 0 occupied by the second UE in the COT and may determine the sub-resource pool for PSFCH in the COT and use that sub-resource pool for PSFCH hashing.

[0099] For example, in some cases, the first UE may determine at least one RB set including resources allocated for the PSCCH from one or more RB sets of unlicensed spectrum occupied by the second UE in the COT. For example, in some cases, the first UE may determine that RB set 0 may include resources allocated for the PSCCH 1502. Thereafter, the first UE may determine a sub-resource pool 1504 for transmitting feedback information on a feedback channel in the COT from a configured larger resource pool 1506 spanning RB sets 0-3. In some cases, the first UE may determine the sub-resource pool 1504 based at least in part on at least one RB set (e.g., RB set 0) including resources allocated for the PSCCH 1502. Thus, as shown, in this case, the sub-resource pool 1504 may be limited to at least one RB set (e.g., RB set 0) including resources allocated for the PSCCH 1502.

[0100] Figure 16 1 is a flow diagram illustrating example operations 1600 for wireless communications, e.g., for sidelink feedback channel resource mapping in an unlicensed spectrum, in accordance with certain aspects of the present disclosure. Operations 1600 may be performed, for example, by a first UE (e.g., UE 120a in wireless communication network 100). Operations 1600 may be implemented as a software component that is executed on one or more processors (e.g., Figure 2 Furthermore, in operation 1600, signals sent and received by the UE may be transmitted by, for example, one or more antennas (e.g., Figure 2 In some aspects, the UE's transmission and / or reception of signals may be implemented by obtaining and / or outputting signals via a bus interface of one or more processors (e.g., controller / processor 280).

[0101] Operations 1600 may begin at box 1602 by receiving one or more transmissions from a second UE on one or more sidelink subchannels spanning one or more sets of resource blocks (RBs) of an unlicensed spectrum occupied by the second UE during a channel occupancy time (COT).

[0102] Operation 1600 may continue at box 1604 by sending feedback information corresponding to the received one or more transmissions to the second UE on the feedback channel based on a mapping between the one or more sidelink subchannels and the feedback channel, wherein the mapping limits the feedback channel to the one or more RB sets of the unlicensed spectrum occupied by at least the second UE in the COT and one or more guard bands between the one or more RB sets.

[0103] In some cases, the mapping defines a separate resource pool for the feedback channel for each of the one or more RB sets occupied by the second UE.

[0104] In some cases, operations 1600 may further include receiving a physical resource indicator (PRI) from the second UE in sidelink control information (SCI) that grants the COT to the first UE, and determining a resource pool for transmitting feedback information on the feedback channel based on the PRI. In some cases, the one or more sidelink subchannels include a sidelink control channel, and the mapping restricts the feedback channel to one or more sets of RBs occupied by the sidelink control channel.

[0105] In other cases, the one or more sidelink subchannels include a sidelink shared channel, and the mapping restricts the feedback channel to one or more RB sets occupied by the sidelink shared channel. In some cases, the sidelink shared channel spans at least two RB sets of the one or more RB sets, and the PRI indicates a resource pool of one of the at least two RB sets for transmitting feedback information on the feedback channel.

[0106] In some cases, the mapping restricts the feedback channel to one or more sets of RBs of the unlicensed spectrum occupied by the second UE.

[0107] Additionally, in some cases, the operations 1600 may further include determining one or more resource pools for transmitting feedback information on a feedback channel, wherein transmitting the feedback information is based on the determined one or more resource pools.

[0108] For example, in some cases, determining one or more resource pools includes determining a resource pool for each of one or more RB sets based at least in part on an indication of a starting RB for the resource pool within the RB set and a number of RBs included in the resource pool within the RB set.

[0109] In some cases, determining the one or more resource pools may include determining a resource pool that spans one or more RB sets occupied by the second UE at the COT based at least in part on an indication of a starting RB of the resource pool and a number of RBs included in the resource pool. Furthermore, in some cases, determining the resource pool that spans the one or more RB sets further includes removing one or more RBs within a guard band from the RBs included in the resource pool.

[0110] In some cases, the operations 1600 may further include determining a configured resource pool for transmitting the feedback information on the feedback channel. In some cases, the configured resource pool is limited to one or more RB sets of unlicensed spectrum occupied by at least the second UE in the COT and one or more guard bands between the one or more RB sets.

[0111] Additionally, in some cases, the operations 1600 may further include receiving information indicating one or more available RB sets of the one or more RB sets occupied by the second UE in the COT, and determining, based on the information indicating the one or more available RB sets, a sub-resource pool from the configured resource pool for transmitting feedback information on the feedback channel in the COT. In some cases, the information indicating the one or more available RB sets of the one or more RB sets occupied by the second UE in the COT is received from the second UE in sidelink control information.

[0112] Furthermore, in some cases, operations 1600 may further include determining at least one RB set of unlicensed spectrum occupied by the second UE in the COT that includes resources allocated for a sidelink shared channel. Furthermore, in some cases, operations 1600 may further include determining, from a configured resource pool, a sub-resource pool for transmitting feedback information on a feedback channel in the COT based at least in part on the at least one RB set of unlicensed spectrum occupied by the second UE in the COT. In some cases, the sub-resource pool may be limited to the at least one RB set that includes resources allocated for the sidelink shared channel.

[0113] Furthermore, in some cases, operations 1600 may further include determining at least one RB set of unlicensed spectrum occupied by the second UE in the COT that includes resources allocated for a sidelink control channel. Furthermore, in some cases, operations 1600 may further include determining, from a configured resource pool, a sub-resource pool for transmitting feedback information on a feedback channel in the COT based at least in part on the at least one RB set of unlicensed spectrum occupied by the second UE in the COT. In some cases, the sub-resource pool may be limited to the at least one RB set that includes resources allocated for the sidelink control channel.

[0114] Figure 17 1700, which may include various components (eg, corresponding to functional building block components) configured to perform operations of the techniques disclosed herein, such as Figure 16. The communication device 1700 includes a processing system 1702 coupled to a transceiver 1708 (e.g., a transmitter and / or a receiver). The transceiver 1708 is configured to transmit and receive signals for the communication device 1700, such as the various signals described herein, via an antenna 1710. The processing system 1702 can be configured to perform processing functions for the communication device 1700, including processing signals received and / or transmitted by the communication device 1700.

[0115] The processing system 1702 includes a processor 1704 coupled to a computer-readable medium / memory 1712 via a bus 1706. In certain aspects, the computer-readable medium / memory 1712 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 1704, cause the processor 1704 to perform Figure 16 , or other operations for performing the various techniques discussed herein for sidelink feedback channel resource mapping in an unlicensed spectrum. In certain aspects, the computer-readable medium / memory 1712 stores code 1714 for receiving, code 1716 for sending, and code 1718 for determining.

[0116] In some cases, the code for receiving 1714 may include: code for receiving one or more transmissions from the second UE on one or more sidelink subchannels spanning one or more sets of resource blocks (RBs) of an unlicensed spectrum occupied by the second UE during a channel occupancy time (COT).

[0117] In some cases, the code for sending 1716 may include: code for sending feedback information corresponding to the received one or more transmissions to the second UE on the feedback channel based on a mapping between the one or more sidelink subchannels and the feedback channel, wherein the mapping limits the feedback channel to the one or more RB sets of the unlicensed spectrum occupied by at least the second UE in the COT and one or more guard bands between the one or more RB sets.

[0118] In some cases, the code for receiving 1714 may include code for receiving a physical resource indicator (PRI) from the second UE in sidelink control information (SCI) granting COT to the first UE.

[0119] In some cases, the code for determining 1718 may include code for determining a resource pool for transmitting feedback information on a feedback channel based on the PRI.

[0120] In some cases, the code for determining 1718 may include code for determining one or more resource pools for transmitting feedback information on a feedback channel, wherein transmitting the feedback information is based on the determined one or more resource pools.

[0121] In some cases, the code for determining 1718 may include: code for determining a resource pool for each of one or more RB sets based at least in part on an indication of a starting RB for the resource pool within the RB set and a number of RBs included in the resource pool within the RB set.

[0122] In some cases, the code for determining 1718 may include code for determining one or more resource pools, including determining a resource pool spanning one or more sets of RBs occupied by the second UE at the COT based at least in part on an indication of a starting RB of the resource pool and a number of RBs included in the resource pool. Furthermore, in some cases, the code for determining 1718 may include code for removing one or more RBs within a guard band from the RBs included in the resource pool.

[0123] In some cases, the code for determining 1718 may include: code for determining a configured resource pool for sending feedback information on a feedback channel, wherein the configured resource pool is limited to one or more RB sets of unlicensed spectrum occupied by at least the second UE in the COT and one or more guard bands between the one or more RB sets.

[0124] In some cases, the code for receiving 1714 may include code for receiving information indicating one or more available RB sets of one or more RB sets occupied by the second UE at the COT. Additionally, in some cases, the code for determining 1718 may include code for determining, from a configured resource pool, a sub-resource pool for transmitting feedback information on a feedback channel at the COT based on the information indicating the one or more available RB sets.

[0125] In addition, in some cases, the code for determining 1718 may include: code for determining at least one RB set including resources allocated for the sidelink shared channel from one or more RB sets of unlicensed spectrum occupied by the second UE in the COT.

[0126] In addition, in some cases, the code 1718 for determining may include: determining a sub-resource pool from the configured resource pool for sending feedback information on the feedback channel at the COT based at least in part on at least one RB set including and allocated for the sidelink shared channel, wherein the sub-resource pool is limited to at least one RB set including resources allocated for the sidelink shared channel.

[0127] Furthermore, in some cases, the code for determining 1718 may include: code for determining at least one RB set including resources allocated for a sidelink control channel from one or more RB sets of unlicensed spectrum occupied by the second UE in the COT; and

[0128] In addition, in some cases, the code for determining 1718 may include: code for determining a sub-resource pool from a configured resource pool for sending feedback information on a feedback channel at a COT based at least in part on at least one RB set including resources allocated for a sidelink control channel, wherein the sub-resource pool is restricted to at least one RB set including and resources allocated for a sidelink control channel.

[0129] In certain aspects, the processor 1704 may include circuitry configured to implement code stored in the computer-readable medium / memory 1712, such as for executing Figure 16 , or other operations for performing the various techniques discussed herein for sidelink feedback channel resource mapping in an unlicensed spectrum. For example, processor 1704 includes circuitry 1724 for receiving, circuitry 1726 for sending, and circuitry 1728 for determining.

[0130] In some cases, the circuitry for receiving 1724 may include circuitry for receiving one or more transmissions from the second UE on one or more sidelink subchannels spanning one or more sets of resource blocks (RBs) of unlicensed spectrum occupied by the second UE during a channel occupancy time (COT).

[0131] In some cases, the circuitry for transmitting 1726 may include circuitry for transmitting feedback information corresponding to the received one or more transmissions to the second UE on a feedback channel based on a mapping between the one or more sidelink subchannels and the feedback channel, wherein the mapping limits the feedback channel to one or more RB sets of unlicensed spectrum occupied by at least the second UE in the COT and one or more guard bands between the one or more RB sets.

[0132] In some cases, the circuitry for receiving 1724 may include circuitry for receiving a physical resource indicator (PRI) from the second UE in sidelink control information (SCI) granting COT to the first UE.

[0133] In some cases, the circuitry for determining 1728 may include circuitry for determining a resource pool for transmitting feedback information on a feedback channel based on the PRI.

[0134] In some cases, the circuitry for determining 1728 may include circuitry for determining one or more resource pools for transmitting the feedback information on the feedback channel, wherein transmitting the feedback information is based on the determined one or more resource pools.

[0135] In some cases, the circuitry for determining 1728 may include circuitry for determining a resource pool for each of one or more RB sets based at least in part on an indication of a starting RB for the resource pool within the RB set and a number of RBs included in the resource pool within the RB set.

[0136] In some cases, the circuitry for determining 1728 may include circuitry for determining one or more resource pools, including determining a resource pool that spans one or more sets of RBs occupied by the second UE at the COT based at least in part on an indication of a starting RB of the resource pool and a number of RBs included in the resource pool. Furthermore, in some cases, the circuitry for determining 1728 may include circuitry for removing one or more RBs within a guard band from the RBs included in the resource pool.

[0137] In some cases, the circuitry for determining 1728 may include circuitry for determining a configured resource pool for sending feedback information on a feedback channel, wherein the configured resource pool is restricted to one or more RB sets of unlicensed spectrum occupied by at least the second UE in the COT and one or more guard bands between the one or more RB sets.

[0138] In some cases, the circuitry for receiving 1724 may include circuitry for receiving information indicating one or more available RB sets of one or more RB sets occupied by the second UE at the COT. Furthermore, in some cases, the circuitry for determining 1728 may include circuitry for determining, from a configured resource pool, a sub-resource pool for transmitting feedback information on a feedback channel at the COT based on the information indicating the one or more available RB sets.

[0139] Furthermore, in some cases, the circuitry for determining 1728 may include: circuitry for determining at least one RB set including resources allocated for a sidelink shared channel from one or more RB sets of unlicensed spectrum occupied by the second UE in the COT; and

[0140] In addition, in some cases, the circuit 1728 for determining may include: a circuit for determining a sub-resource pool from the configured resource pool for sending feedback information on the feedback channel at the COT based at least in part on at least one RB set including resources allocated for the sidelink shared channel, wherein the sub-resource pool is restricted to at least one RB set including resources allocated for the sidelink shared channel.

[0141] Furthermore, in some cases, the circuitry for determining 1728 may include: circuitry for determining at least one set of RBs including resources allocated for a sidelink control channel from one or more sets of RBs of unlicensed spectrum occupied by the second UE at the COT; and

[0142] In addition, in some cases, the circuit 1728 for determining may include: a circuit for determining a sub-resource pool from the configured resource pool for sending feedback information on the feedback channel at the COT based at least in part on at least one RB set including resources allocated for the sidelink control channel, wherein the sub-resource pool is restricted to at least one RB set including resources allocated for the sidelink control channel.

[0143] Example aspects

[0144] Aspect 1: A method for wireless communication by a first user equipment (UE), comprising: receiving one or more transmissions from a second UE on one or more sidelink subchannels, wherein the one or more sidelink subchannels span one or more resource block (RB) sets of an unlicensed spectrum occupied by the second UE during a channel occupancy time (COT); and sending feedback information corresponding to the received one or more transmissions to the second UE on the feedback channel based on a mapping between the one or more sidelink subchannels and a feedback channel, wherein the mapping limits the feedback channel to at least the one or more RB sets of the unlicensed spectrum occupied by the second UE during the COT and one or more guard bands between the one or more RB sets.

[0145] Aspect 2: The method according to aspect 1, wherein the mapping defines a separate resource pool for the feedback channel for each of the one or more RB sets occupied by the second UE.

[0146] Aspect 3: The method as described in one or more aspects of Aspect 1 or Aspect 2 further includes: receiving a physical resource indicator (PRI) from the second UE in the sidelink control information (SCI) that authorizes the COT to the first UE, and determining a resource pool for sending feedback information on the feedback channel based on the PRI.

[0147] Aspect 4: The method of aspect 3, wherein the one or more sidelink subchannels include a sidelink control channel, and the mapping restricts the feedback channel to one or more sets of RBs occupied by the sidelink control channel.

[0148] Aspect 5: The method of aspect 3, wherein the one or more sidelink subchannels include a sidelink shared channel, and the mapping restricts the feedback channel to one or more sets of RBs occupied by the sidelink shared channel.

[0149] Aspect 6: A method as described in Aspect 5, wherein the sidelink shared channel spans at least two RB sets among one or more RB sets, and the PRI indicates that a resource pool of one RB set among the at least two RB sets is used to send feedback information on the feedback channel.

[0150] Aspect 7: The method according to any one of aspects 1-6, wherein the mapping restricts the feedback channel to one or more RB sets of the unlicensed spectrum occupied by the second UE.

[0151] Aspect 8: The method according to any one of aspects 1-7 further comprises: determining one or more resource pools for sending feedback information on a feedback channel, wherein sending the feedback information is based on the determined one or more resource pools.

[0152] Aspect 9: A method as described in Aspect 8, wherein determining one or more resource pools includes: determining a resource pool for each RB set of one or more RB sets based at least in part on an indication of a starting RB of the resource pool within the RB set and the number of RBs included in the resource pool within the RB set.

[0153] Aspect 10: A method as described in Aspect 8, wherein determining one or more resource pools includes: determining a resource pool spanning one or more RB sets occupied by the second UE in the COT based at least in part on an indication of a starting RB of the resource pool and the number of RBs included in the resource pool.

[0154] Aspect 11: The method according to aspect 10, wherein determining a resource pool spanning one or more RB sets further comprises: removing RBs within one or more guard bands from the RBs included in the resource pool.

[0155] Aspect 12: The method as described in any one of Aspects 1-11 further includes: determining a configured resource pool for sending feedback information on a feedback channel, wherein the configured resource pool is limited to the one or more RB sets of the unlicensed spectrum occupied by at least the second UE in the COT and one or more guard bands between the one or more RB sets.

[0156] Aspect 13: The method as described in Aspect 12 further includes: receiving information indicating one or more available RB sets of one or more RB sets occupied by the second UE in the COT; and, based on the information indicating the one or more available RB sets, determining a sub-resource pool from the configured resource pool for sending feedback information on the feedback channel in the COT.

[0157] Aspect 14: The method of aspect 13, wherein the information indicating one or more available RB sets of one or more RB sets occupied by the second UE at the COT is received from the second UE in sidelink control information.

[0158] Aspect 15: The method as described in Aspect 12 further includes: determining at least one RB set including resources allocated for a sidelink shared channel from one or more RB sets of an unlicensed spectrum occupied by the second UE in the COT; and, at least in part based on the at least one RB set including resources allocated for the sidelink shared channel, determining a sub-resource pool from a configured resource pool for sending feedback information on a feedback channel in the COT, wherein the sub-resource pool is limited to at least one RB set including resources allocated for the sidelink shared channel.

[0159] Aspect 16: The method as described in Aspect 12 further includes: determining at least one RB set including resources allocated for a sidelink control channel from one or more RB sets of the unlicensed spectrum occupied by the second UE in the COT; and, at least in part based on the at least one RB set including resources allocated for the sidelink control channel, determining a sub-resource pool from the configured resource pool for sending feedback information on the feedback channel in the COT, wherein the sub-resource pool is limited to at least one RB set including resources allocated for the sidelink control channel.

[0160] Other considerations

[0161] 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" are often used interchangeably. A CDMA network can implement radio technologies such as Universal Terrestrial Radio Access (UTRA) and cdma2000. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers the IS-2000 standard, the IS-95 standard, and the IS-856 standard. 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, and the like. 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 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.

[0162] In 3GPP, the term "cell" can refer to the coverage area of ​​a Node B (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 "base station," next-generation Node B (gNB or gNodeB), access point (AP), distributed unit (DU), carrier, or transmit / receive point (TRP) are used interchangeably. A base station (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., several kilometers in radius) and can allow unrestricted access to UEs with service subscriptions. A picocell can cover a relatively small geographic area and can allow unrestricted access to UEs with service subscriptions. A femtocell can cover a relatively small geographic area (e.g., a home) and can allow restricted access to UEs associated with the femtocell (e.g., UEs in a closed subscriber group (CSG) or UEs for users in a home). A base station for a macrocell can be referred to as a macro BS. A base station for a picocell can be referred to as a pico BS. A base station for a femtocell can be referred to as a femto BS or a home BS.

[0163] A 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 smartphone, 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, an appliance, a medical device or medical apparatus, a biometric sensor / 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 device, 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 base station, another device (e.g., a remote device), or some other entity. A wireless node can provide connectivity to or from 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.

[0164] In some examples, access to the air interface can be scheduled. A scheduling entity (e.g., BS) allocates resources for communication between some or all devices and apparatuses within its service area or cell. A scheduling entity can be responsible for scheduling, allocating, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communications, the subordinate entity adopts the resources allocated by the scheduling entity. The base station is not the only entity that can act as a scheduling entity. In some examples, a UE can serve as a scheduling entity and can schedule resources for one or more subordinate entities (e.g., one or more other UEs), and other UEs can utilize the resources scheduled by the UE for wireless communication. In some examples, a UE can serve as a scheduling entity in a point-to-point (P2P) network and / or in a mesh network. In the mesh network example, in addition to communicating with the scheduling entity, UEs can also communicate directly with each other.

[0165] The methods disclosed herein include one or more steps or actions for implementing these methods. Method steps and / or actions may be interchangeable with each other 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 the specific steps and / or actions may be modified without departing from the scope of the claims.

[0166] 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. For example, "at least one of a, b, or c" is intended to encompass a, b, c, ab, ac, bc, and abc, as well as any combination and multiples of the same element (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other order of a, b, and c).

[0167] As used herein, the term "determine" encompasses a wide variety of actions. For example, "determine" may include calculating, computing, processing, deriving, investigating, searching (e.g., searching in a table, database, or other data structure), ascertaining, and the like. Furthermore, "determine" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. Furthermore, "determine" may include resolving, selecting, choosing, establishing, and the like.

[0168] The preceding description is provided to enable those skilled in the art to implement the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Accordingly, the claims are not intended to be limited to the several aspects shown herein, but rather to the full scope consistent with the claim language, wherein, unless otherwise specified, references to singular elements are not intended to mean "one and only one," but rather "one or more." Unless otherwise specifically stated, the term "some" refers to one or more. All structural and functional equivalents to the elements described throughout this disclosure that are known or later become known to those of ordinary skill 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 dedicated to the public, regardless of whether such disclosure is explicitly recited in the claims. No claim shall be construed under 35 U.S.C. § 112(f) unless the element is explicitly recited using the phrase "means for..." or, in the case of a method claim, the phrase "step for..."

[0169] The various operations of the above method can be performed by any suitable unit capable of performing the corresponding functions. The unit 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, in the case of the operations shown in the figures, those operations may have corresponding corresponding functional module components with similar numbers.

[0170] 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 digital signal processor (DSP), an application-specific integrated circuit (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. A processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration.

[0171] If implemented in hardware, an exemplary hardware configuration may include a processing system in a wireless node. The processing system may be implemented using 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 various circuits (including processors, machine-readable media, and bus interfaces) together. The bus interface may be used to connect a network adapter, etc., to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the case of 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 well known in the art and will not be described further. The processor may be implemented using one or more general and / or special purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuits capable of executing 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.

[0172] If implemented in software, these functions may be stored or transmitted as one or more instructions or codes via a computer-readable medium. Software should be broadly interpreted to mean instructions, data, or any combination thereof, whether referring to software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media include computer storage media and communication media, including 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 a machine-readable storage medium. The computer-readable storage medium may be coupled to the processor so that the processor can read information from and write information to the storage medium. Alternatively, the storage medium may be an integral part of the processor. As examples, the machine-readable medium may include a transmission line, a carrier modulated with data, and / or a computer-readable storage medium storing instructions separate from the wireless node, all of which may be accessed by the processor via a bus interface. Alternatively or in addition, the machine-readable medium or any portion thereof may be integrated into the processor, such as may be the case with a cache and / or general register file. As examples, examples of machine-readable storage media may include, for example, 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. The machine-readable medium may be embodied in a computer program product.

[0173] A software module may include a single instruction or many instructions and may be distributed across several different code segments, different programs, and multiple storage media. A computer-readable medium may include multiple 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 be distributed across multiple storage devices. For example, when a triggering event occurs, a software module may be loaded from a hard drive into RAM. During execution of a software module, the processor may load some instructions into a cache to increase access speed. One or more caches may then be loaded into a general register file for execution by the processor. When referring to the functions of a software module below, it should be understood that these functions are implemented by the processor when instructions are executed from the software module.

[0174] 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 definition of medium includes the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Optical disks, where magnetic disks typically reproduce data magnetically, and optical disks reproduce data optically using lasers. Thus, in some aspects, computer-readable media may include non-transitory computer-readable media (e.g., tangible media). Furthermore, for other aspects, computer-readable media may include transitory computer-readable media (e.g., signals). Combinations of the above should also be included within the scope of computer-readable media.

[0175] 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, the instructions being executable by one or more processors to perform the operations described herein. For example, the instructions are for performing the operations described herein and in Figure 16 The operations shown in and / or instructions for other operations described herein for sending feedback information on a sidelink feedback channel in an unlicensed spectrum based on a sidelink feedback channel resource mapping.

[0176] In addition, it should be understood that the modules and / or other appropriate units for performing the methods and techniques described herein can be downloaded and / or otherwise obtained by the user terminal and / or base station when appropriate. For example, such a device can be coupled to a server to facilitate the transmission of units for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage device (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or a floppy disk) so that the user terminal and / or base station can obtain the various methods when the storage unit is coupled or provided to the device. In addition, any other suitable technology for providing the methods and techniques described herein to a device can be used.

[0177] It should be understood that the claims are not limited to the precise configuration and components illustrated above, and that various modifications, changes and variations may be made in the arrangement, 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: receiving one or more transmissions from a second UE on one or more sidelink subchannels, the one or more sidelink subchannels spanning a set of one or more resource blocks (RBs) of an unlicensed spectrum occupied by the second UE during a channel occupancy time (COT); as well as Feedback information corresponding to the received one or more transmissions is sent to the second UE on the feedback channel based on a mapping between the one or more sidelink subchannels and a feedback channel, wherein the mapping limits the feedback channel to the one or more RB sets of the unlicensed spectrum occupied by at least the second UE in the COT and one or more guard bands between the one or more RB sets.

2. The method according to claim 1, wherein The mapping defines a separate resource pool for the feedback channel for each of the one or more RB sets occupied by the second UE.

3. The method according to claim 1, further comprising: receiving a physical resource indicator (PRI) from the second UE in sidelink control information (SCI) granting the COT to the first UE; as well as Based on the PRI, a resource pool for sending the feedback information on the feedback channel is determined.

4. The method according to claim 3, wherein: The one or more sidelink subchannels include a sidelink control channel; and The mapping restricts the feedback channel to one or more sets of RBs occupied by the sidelink control channel.

5. The method according to claim 3, wherein: The one or more sidelink sub-channels include a sidelink shared channel; and The mapping restricts the feedback channel to one or more sets of RBs occupied by the sidelink shared channel.

6. The method according to claim 5, wherein: The sidelink shared channel spans at least two RB sets among the one or more RB sets; and The PRI indicates that the resource pool of one of the at least two RB sets is used for sending the feedback information on the feedback channel.

7. The method according to claim 1, wherein The mapping restricts the feedback channel to the one or more sets of RBs of the unlicensed spectrum occupied by the second UE.

8. The method according to claim 1, further comprising: One or more resource pools are determined for sending the feedback information on the feedback channel, wherein sending the feedback information is based on the determined one or more resource pools.

9. The method according to claim 8, wherein Determining the one or more resource pools includes determining a resource pool for each of the one or more RB sets based at least in part on: an indication of a starting RB of the resource pool within the RB set; and The number of RBs included in the resource pool within the RB set.

10. The method according to claim 8, wherein Determining the one or more resource pools includes determining a resource pool spanning the one or more sets of RBs occupied by the second UE at the COT based at least in part on: an indication of a starting RB of the resource pool; and The number of RBs included in the resource pool.

11. The method according to claim 10, wherein: Determining the resource pool spanning the one or more RB sets further includes removing RBs within the one or more guard bands from the RBs included in the resource pool.

12. The method according to claim 1, further comprising: Determine a configured resource pool for sending the feedback information on the feedback channel, wherein the configured resource pool is restricted to the one or more RB sets of the unlicensed spectrum occupied by at least the second UE in the COT and one or more guard bands between the one or more RB sets.

13. The method according to claim 12, further comprising: receiving information indicating one or more available RB sets of the one or more RB sets occupied by the second UE in the COT; as well as Based on the information indicating the one or more available RB sets, a sub-resource pool is determined from the configured resource pool for sending the feedback information on the feedback channel at the COT.

14. The method according to claim 13, wherein The information indicating one or more available RB sets of the one or more RB sets occupied by the second UE at the COT is received from the second UE in sidelink control information.

15. The method according to claim 12, further comprising: determining at least one RB set including resources allocated for a sidelink shared channel from the one or more RB sets of the unlicensed spectrum occupied by the second UE in the COT; as well as determining, from the configured resource pool, a sub-resource pool for sending the feedback information on the feedback channel at the COT based at least in part on the at least one RB set including the resources allocated for the sidelink shared channel, wherein the sub-resource pool is restricted to the at least one RB set including the resources allocated for the sidelink shared channel.

16. The method according to claim 12, further comprising: determining at least one RB set including resources allocated for a sidelink control channel from the one or more RB sets of the unlicensed spectrum occupied by the second UE in the COT; as well as determining, from the configured resource pool, a sub-resource pool for sending the feedback information on the feedback channel at the COT based at least in part on the at least one RB set including the resources allocated for the sidelink control channel, wherein the sub-resource pool is restricted to the at least one RB set including the resources allocated for the sidelink control channel.

17. A first user equipment (UE) for wireless communication, comprising means for performing the method according to any one of claims 1-16.

18. A first user equipment (UE) for wireless communication, comprising: Memory; as well as A processor coupled to the memory, the memory and the processor being configured to perform the method according to any one of claims 1-16.

19. A computer-readable medium comprising instructions that, when executed by at least one processor of a first user equipment (UE), cause the at least one processor to perform the method according to any one of claims 1-16.

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