Sidelink communications with hybrid automatic repeat request (HARQ) feedback transmissions in unlicensed spectrum

Abstract

Certain aspects of the present disclosure provide techniques for slot formats for sidelink communications. A method executable by a user equipment (UE) includes transmitting a data signal; suppressing transmission during a gap portion occurring in time after transmitting the data signal, wherein the gap portion has a duration less than or equal to a threshold; receiving a feedback signal after the gap portion, wherein the feedback signal comprises at least one signal and hybrid automatic repeat request (HARQ) feedback for the data signal; receiving another signal; and adjusting a gain applied to the other signal based on the signal.

Description

[0001] This application is a divisional application of Chinese invention patent application 202180043826.4 (PCT / US2021 / 038769) entitled “Sidelink communication with hybrid automatic repeat request (HARQ) feedback transmission in unlicensed spectrum”, filed on June 23, 2021. Technical Field

[0002] Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for sidelink communications in an unlicensed spectrum. Background Art

[0003] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, etc. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access systems include 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems, to name a few.

[0004] 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, region, and even global level. New radio (e.g., 5G NR) is an example of an emerging telecommunication standard. NR is an enhancement to the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by using OFDMA with a cyclic prefix (CP) on the downlink (DL) and uplink (UL) to improve spectrum efficiency, reduce costs, improve services, utilize new spectrum, and better integrate with other open standards. To this end, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0005] However, as the demand for mobile broadband access continues to grow, there is a need for further improvements to NR and LTE technologies. Preferably, these improvements should also apply to other multiple access technologies and the telecommunication standards that employ them. Summary of the Invention

[0006] 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 disclosure as expressed in 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 sidelink communications in an unlicensed spectrum.

[0007] Certain aspects of the subject matter described in this disclosure can be implemented in a method for wireless communication. The method generally includes: transmitting a data signal; refraining from transmitting during a gap portion occurring temporally after transmitting the data signal, wherein the gap portion has a duration less than or equal to a threshold; receiving a feedback signal after the gap portion, wherein the feedback signal includes at least one signal and hybrid automatic repeat request (HARQ) feedback for the data signal; receiving another signal; and adjusting a gain applied to the other signal based on the signal.

[0008] Certain aspects of the subject matter described in this disclosure can be implemented in a method for wireless communication. The method generally includes: receiving an indication in sidelink control information (SCI) that hybrid automatic repeat request (HARQ) feedback is enabled for a data signal; receiving the data signal; refraining from transmitting during a gap portion occurring temporally after receiving the data signal, wherein the gap portion has a duration less than or equal to a threshold; and transmitting a feedback signal comprising a signal and HARQ feedback for the data signal.

[0009] Certain aspects of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication. The apparatus generally includes a memory and a processor coupled to the memory. The processor and memory are configured to: transmit a data signal, and refrain from transmitting during a gap portion that occurs temporally after the transmission of the data signal, wherein the gap portion has a duration less than or equal to a threshold; receive a feedback signal after the gap portion, wherein the feedback signal includes at least one signal and hybrid automatic repeat request (HARQ) feedback for the data signal; receive another signal; and adjust a gain applied to the other signal based on the signal.

[0010] Certain aspects of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication. The apparatus generally includes a memory and a processor coupled to the memory. The processor and memory are configured to: receive an indication in sidelink control information (SCI) that hybrid automatic repeat request (HARQ) feedback is enabled for a data signal; receive the data signal; refrain from transmitting during a gap portion that occurs temporally after receiving the data signal, wherein the gap portion has a time duration less than or equal to a threshold; and transmit a feedback signal after the gap portion, the feedback signal comprising a signal and HARQ feedback for the data signal.

[0011] Certain aspects of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication. The apparatus generally includes: means for transmitting a data signal; refraining from transmitting during a gap portion occurring temporally after transmitting the data signal, wherein the gap portion has a duration less than or equal to a threshold; means for receiving a feedback signal after the gap portion, wherein the feedback signal includes at least one signal and hybrid automatic repeat request (HARQ) feedback for the data signal; means for receiving another signal; and means for adjusting a gain applied to the other signal based on the signal.

[0012] Certain aspects of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication. The apparatus generally includes: means for receiving an indication in sidelink control information (SCI) that hybrid automatic repeat request (HARQ) feedback is enabled for a data signal; means for receiving the data signal; means for refraining from transmitting during a gap portion occurring temporally after receiving the data signal, wherein the gap portion has a duration less than or equal to a threshold; and means for transmitting a feedback signal comprising a signal and HARQ feedback for the data signal.

[0013] Certain aspects of the subject matter described in this disclosure can be implemented in a computer-readable medium for wireless communications. The computer-readable medium includes instructions that, when executed by a processing system, cause the processing system to perform operations generally including: transmitting a data signal; refraining from transmitting during a gap portion that occurs temporally after transmitting the data signal, wherein the gap portion has a duration less than or equal to a threshold; receiving a feedback signal after the gap portion, wherein the feedback signal includes at least one signal and hybrid automatic repeat request (HARQ) feedback for the data signal; receiving another signal; and adjusting a gain applied to the other signal based on the signal.

[0014] Certain aspects of the subject matter described in this disclosure can be implemented in a computer-readable medium for wireless communications. The computer-readable medium includes instructions that, when executed by a processing system, cause the processing system to perform operations generally including: receiving an indication in sidelink control information (SCI) that hybrid automatic repeat request (HARQ) feedback is enabled for a data signal; receiving the data signal; refraining from transmitting during a gap portion that occurs temporally after receiving the data signal, wherein the gap portion has a duration that is less than or equal to a threshold; and transmitting a feedback signal comprising a signal and HARQ feedback for the data signal.

[0015] Certain aspects of the subject matter described in this disclosure can be implemented in a method for wireless communication. The method generally includes: transmitting a data signal; refraining from transmitting during a gap portion occurring temporally after transmitting the data signal, wherein the gap portion has a duration less than or equal to a value; and receiving a feedback signal after the gap portion, wherein the feedback signal includes at least an automatic gain control (AGC) signal and hybrid automatic repeat request (HARQ) feedback for the data signal.

[0016] Certain aspects of the subject matter described in this disclosure can be implemented in a method for wireless communication. The method generally includes receiving a data signal; refraining from transmitting during a gap portion occurring temporally after receiving the data signal, wherein the gap portion has a duration less than or equal to a value; and transmitting a feedback signal comprising an automatic gain control (AGC) signal and hybrid automatic repeat request (HARQ) feedback for the data signal.

[0017] Certain aspects of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication. The apparatus generally includes: means for transmitting a data signal; means for refraining from transmitting during a gap portion occurring temporally after transmitting the data signal, wherein the gap portion has a duration less than or equal to a value; and means for receiving a feedback signal after the gap portion, wherein the feedback signal includes at least an automatic gain control (AGC) signal and hybrid automatic repeat request (HARQ) feedback for the data signal.

[0018] Certain aspects of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication. The apparatus generally includes: means for receiving a data signal; means for refraining from transmitting during a gap portion occurring temporally after receipt of the data signal, wherein the gap portion has a duration less than or equal to a value; and means for transmitting a feedback signal comprising an automatic gain control (AGC) signal and hybrid automatic repeat request (HARQ) feedback for the data signal.

[0019] Certain aspects of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication. The apparatus generally includes a memory; and a processor coupled to the memory, the memory and the processor being configured to: transmit a data signal; refrain from transmitting during a gap portion occurring temporally after the transmission of the data signal, wherein the gap portion has a duration less than or equal to a value; and receive a feedback signal after the gap portion, wherein the feedback signal includes at least an automatic gain control (AGC) signal and hybrid automatic repeat request (HARQ) feedback for the data signal.

[0020] Certain aspects of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication. The apparatus generally includes a memory; and a processor coupled to the memory, the memory and the processor being configured to: receive a data signal; refrain from transmitting during a gap portion occurring temporally after receipt of the data signal, wherein the gap portion has a duration less than or equal to a value; and transmit a feedback signal comprising an automatic gain control (AGC) signal and hybrid automatic repeat request (HARQ) feedback for the data signal.

[0021] Certain aspects of the subject matter described in this disclosure can be implemented in a computer-readable medium for wireless communications. The computer-readable medium includes instructions that, when executed by a processing system, cause the processing system to perform operations generally including: transmitting a data signal; refraining from transmitting during a gap portion that occurs temporally after transmitting the data signal, wherein the gap portion has a duration less than or equal to a value; and receiving a feedback signal after the gap portion, wherein the feedback signal includes at least an automatic gain control (AGC) signal and hybrid automatic repeat request (HARQ) feedback for the data signal.

[0022] Certain aspects of the subject matter described in this disclosure can be implemented in a computer-readable medium for wireless communications. The computer-readable medium includes instructions that, when executed by a processing system, cause the processing system to perform operations generally including: receiving a data signal; refraining from transmitting during a gap portion that occurs temporally after receiving the data signal, wherein the gap portion has a duration that is less than or equal to a value; and transmitting a feedback signal comprising an automatic gain control (AGC) signal and hybrid automatic repeat request (HARQ) feedback for the data signal.

[0023] To accomplish the foregoing and related ends, one or more aspects comprise 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 the one or more aspects. However, these features are indicative of but a few of the various ways in which the principles of the various aspects may be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order that the manner in which the above-recited features of the present disclosure may be understood in detail, a more particular description of what has been briefly summarized above may be given with reference to various aspects, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only certain aspects of the disclosure and are not to be considered limiting of its scope, as the description may admit to other equally effective aspects.

[0025] Figure 1 is a block diagram conceptually illustrating an example wireless communication network in accordance with certain aspects of the present disclosure.

[0026] Figure 2 is a block diagram conceptually illustrating designs of example base stations (BSs) and user equipment (UEs) in accordance with certain aspects of the present disclosure.

[0027] 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.

[0028] Figure 4A and Figure 4B A pictorial representation of an example vehicle-to-everything (V2X) system is shown, in accordance with certain aspects of the present disclosure.

[0029] Figure 5 is a diagram illustrating an example model of multiple wireless devices operating in an unlicensed spectrum in accordance with certain aspects of the present disclosure.

[0030] Figure 6 is an example transmission timeline for sidelink communications in accordance with certain aspects of the present disclosure.

[0031] Figure 7 is an example transmission timeline for sidelink communications in accordance with certain aspects of the present disclosure.

[0032] Figure 8A and 8B is an example transmission timeline for sidelink communications according to aspects of the present disclosure.

[0033] Figure 9A and 9B is an example transmission timeline for sidelink communications with a gap at the end of a time slot in accordance with aspects of the present disclosure.

[0034] Figure 10 is a flow diagram illustrating example operations for wireless communications by a UE, in accordance with certain aspects of the present disclosure.

[0035] Figure 11is a flow diagram illustrating example operations for wireless communications by a UE, in accordance with certain aspects of the present disclosure.

[0036] Figure 12 Illustrated in accordance with various aspects of the present disclosure may include being configured to perform Figure 10 The various components of the communication equipment in each operation.

[0037] Figure 13 Illustrated in accordance with various aspects of the present disclosure may include being configured to perform Figure 11 The various components of the communication equipment in each operation.

[0038] 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 in other aspects without specific recitation. DETAILED DESCRIPTION

[0039] Various aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for sidelink communications with hybrid automatic repeat request (HARQ) feedback transmission in unlicensed spectrum. Unlicensed spectrum refers to any frequency band that is not subject to licensed use under regulatory practices, making the band(s) open for use by any device (not just devices with a license to use the specific band(s)). Example sidelink communications include vehicle-to-everything (V2X) communications. While certain aspects may be discussed with respect to V2X communications in a V2X communication system, it should be noted that various aspects are equally applicable to other suitable types of sidelink communication systems.

[0040] In certain aspects, for wireless communications in an unlicensed spectrum, a wireless communication device (e.g., a UE and / or a Wi-Fi device) may perform a channel access procedure known as a listen-before-talk (LBT) procedure, in which the device may transmit when a channel corresponding to a frequency band is sensed to be empty (e.g., idle) before transmitting. The time period during which the LBT procedure is performed before transmitting may be referred to as a listening opportunity. In the LBT procedure, the wireless communication device measures the energy on the frequency band and refrains from transmitting on the frequency band when the frequency band is busy, and determines that it can communicate on the frequency band when the frequency band is idle. As used herein, the term "idle" with respect to a frequency band means that the energy measured on the frequency band by the device determining the idleness is below a threshold level. As used herein, the term "busy" with respect to a frequency band means that the energy measured on the frequency band by the device determining the idleness is above a threshold level. Such energy may be caused by noise or signals within the frequency band.

[0041] In certain aspects, a device may perform an LBT procedure on an unlicensed band before transmitting a signal on the unlicensed band if a time period (e.g., a transmission gap) since the device previously transmitted on the unlicensed band is greater than a certain threshold (e.g., 16 μs).

[0042] In certain aspects, sidelink communications may be scheduled with gap periods (e.g., gap symbols within a time slot) during which the UE does not transmit or receive. In certain aspects, the gap periods may be referred to as gap symbols. Gap symbols may enable the UE to switch from a receive mode to a transmit mode, or vice versa. Gap symbols may also account for delayed signal communications, such as propagation delays caused by the UE not being synchronized in time.

[0043] The sidelink communication may, for example, enable hybrid automatic repeat request (HARQ) feedback to provide a certain quality of service (QoS level). In the HARQ feedback process, the UE transmitting the data may retransmit a packet if a previous transmission of the packet failed; for example, the UE may retransmit the packet after receiving a negative acknowledgment (NACK) feedback in response to the packet from the intended recipient of the packet (e.g., the receiving UE), indicating that the intended recipient received but failed to successfully decode the packet.

[0044] Sidelink HARQ feedback transmission in an unlicensed band may also be subject to the availability of the unlicensed band, as discussed with respect to the LBT procedure. In some examples of the HARQ feedback mechanism, a physical sidelink feedback channel (PSFCH) resource may be configured in every N time periods (e.g., time slots), for example, where N may be an integer (e.g., 0, 1, 2, or 4). In one example, the HARQ feedback timeline may be n+k, meaning that for a physical sidelink shared channel (PSSCH) transmission in time slot n, the receiving UE will transmit HARQ feedback in time slot n+k, where time slot n+k is the first time slot with allocated PSFCH resources satisfying k≥2. In some examples of HARQ feedback techniques, a PSFCH transmission may occupy two time periods (e.g., symbols) of a time slot. In one or more examples, the PSFCH transmissions on the two symbols may be identical, but the UE receiving the PSFCH may decode the second symbol in time and perform automatic gain control (AGC) training using the first symbol in time, which may be used to adjust the gain applied to the signal received from that particular UE.

[0045] In certain situations, sidelink devices may use automatic gain control signals to account for the near-far effect of received sidelink signals. Sidelink signals received at a receiving UE from different transmitting devices may vary in power, for example, due to varying distances between the transmitting and receiving UEs. Automatic gain control signals may be transmitted by a transmitting UE to enable the receiving UE to adjust the gain applied to the received signal.

[0046] In some cases, HARQ feedback transmission resources may not be guaranteed, for example, due to the unlicensed band being occupied by other wireless communication devices (such as Wi-Fi devices). According to various aspects of the present disclosure, a technique is provided for transmitting sidelink data transmission and sidelink feedback for sidelink data transmission without performing LBT or other channel sensing on the unlicensed band. For example, after a certain gap period, a receiving UE that has received data and transmitted HARQ feedback for the data may begin transmitting a signal (e.g., an AGC signal) to occupy the unlicensed band. While transmitting the AGC signal, the receiving UE may process the signal from the transmitting UE, generate HARQ feedback, and transmit the HARQ feedback to the transmitting UE without having to perform LBT to transmit the HARQ feedback. Specifically, the AGC signal continues to occupy the unlicensed band, thereby ensuring that other devices refrain from occupying the unlicensed band, so that it is not necessary to perform LBT to ensure that the unlicensed band remains unoccupied. Aspects of the present disclosure may provide HARQ feedback performance, which may facilitate lower latency and / or higher data rates, eg, due to the ability to send HARQ feedback without performing additional LBT or other channel sensing, as discussed.

[0047] Such techniques may be used, for example, in sidelink communications between wireless communication devices. In other examples, the wireless communication devices may include cellular vehicle-to-everything (CV2X) devices. It should be noted that while certain aspects are described with respect to CV2X devices and communications in unlicensed bands, it can be appreciated that various aspects may be similarly applicable to other scenarios, such as any communications in unlicensed bands (e.g., sidelink communications), communications in licensed bands (e.g., sidelink communications), and the like.

[0048] The electromagnetic spectrum (such as in licensed bands) is typically subdivided into various classes, bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating bands have been identified as frequency range designations FR1 (410 MHz–7.125 GHz) and FR2 (24.25 GHz–52.6 GHz). It should be understood that although a portion of FR1 is greater than 6 GHz, FR1 is often (interchangeably) referred to as the “sub-6 GHz” band in various documents and articles. Similar naming issues sometimes arise with respect to FR2, which is often (interchangeably) referred to as the “millimeter wave” band in various documents and articles, although it is different from the extremely high frequency (EHF) band (30 GHz–300 GHz) identified as the “millimeter wave” band by the International Telecommunication Union (ITU).

[0049] Frequencies between FR1 and FR2 are generally referred to as mid-band frequencies. Recent 5G NR research has identified the operating bands of these mid-band frequencies as frequency range designation FR3 (7.125 GHz–24.25 GHz). Frequency bands falling within FR3 can inherit FR1 characteristics and / or FR2 characteristics, and thus can effectively extend the features of FR1 and / or FR2 to mid-band frequencies. Additionally, higher frequency bands are currently being explored to extend 5G NR operation to above 52.6 GHz. For example, three higher operating bands have been identified as frequency range designations FR4a or FR4-1 (52.6 GHz–71 GHz), FR4 (52.6 GHz–114.25 GHz), and FR5 (114.25 GHz–300 GHz). Each of these higher frequency bands falls within the EHF band.

[0050] In view of the above aspects, unless otherwise specified, it should be understood that the terms "sub-6 GHz" and the like, if used herein, may broadly refer to frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies. Furthermore, unless otherwise specified, it should be understood that the terms "millimeter wave" and the like, if used herein, may broadly refer to frequencies that may include mid-band frequencies, may be within FR2, FR4, FR4-a or FR4-1 and / or FR5, or may be within the EHF band.

[0051] The following description provides examples of transmitting sidelink data transmission and sidelink feedback for the sidelink data transmission in the same time period (e.g., time slot) in a wireless communication system and is not intended to limit the scope, applicability, or examples set forth in the claims. Changes may be made to the functions and arrangements of the elements discussed without departing from the scope of this disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For example, the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. Moreover, features described with reference to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of this disclosure is intended to cover such apparatus or methods practiced using other structures, functionalities, or structures and functionalities that are supplemental to or in addition to the various aspects of this disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be implemented by one or more elements of the claims. 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 superior to or preferable to other aspects.

[0052] In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a specific radio access technology (RAT) and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, air interface, etc. A frequency may also be referred to as a carrier, subcarrier, frequency channel, tone, subband, etc. Each frequency may support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs.

[0053] The techniques described herein can be used for various wireless networks and radio technologies. Although various aspects may be described herein using terms typically associated with 3G, 4G, and / or new radio (e.g., 5G NR) wireless technologies, various aspects of the present disclosure may be applied in communication systems based on other generations.

[0054] NR access can support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidths (e.g., 80 MHz or greater), millimeter wave (mmW) targeting high carrier frequencies (e.g., 24 GHz to 53 GHz or greater), massive machine type communications (MTC) targeting non-backward-compatible MTC technologies, and / or mission-critical services targeting ultra-reliable low latency communications (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTIs) to meet corresponding quality of service (QoS) requirements. In addition, these services can coexist in the same subframe. NR supports beamforming, and the beam direction can be dynamically configured. MIMO transmission with precoding is also supported. MIMO configurations in the DL can support up to 8 transmit antennas (with multi-layer DL transmission of up to 8 streams) and up to 2 streams per UE. Multi-layer transmission of up to 2 streams per UE can be supported. Aggregation of multiple cells can be supported using up to 8 serving cells.

[0055] Figure 1 An example wireless communication network 100 is illustrated in which aspects of the present disclosure may be performed. For example, the wireless communication network 100 may be a NR system (e.g., a 5G NR network). Figure 1 As shown, wireless communication network 100 may be in communication with a core network 132. Core network 132 may be in communication with one or more base stations (BSs) 110 and / or user equipments (UEs) 120 in wireless communication network 100 via one or more interfaces.

[0056] According to certain aspects, BS 110 and UE 120 may be configured for sidelink communication. Figure 1, UE 120a includes a sidelink manager 122. In certain aspects, according to aspects of the present disclosure, the sidelink manager 122: refrains from transmitting during a gap portion of a first symbol of a time slot, wherein the first symbol includes the gap portion and an automatic gain control (AGC) portion, wherein the first symbol follows a data signal; receives a signal (e.g., an AGC signal for AGC by a receiving UE) during the AGC portion of the first symbol; and receives hybrid automatic repeat request (HARQ) feedback for the data signal during a second symbol of the time slot, wherein the second symbol follows (e.g., and is adjacent in time to) the AGC signal. For certain aspects, the sidelink manager 122 may: transmit a data signal; refrain from transmitting during a gap portion that occurs temporally after the transmission of the data signal, wherein the gap portion has a duration less than or equal to a threshold; receive a feedback signal after the gap portion, wherein the feedback signal includes at least a signal and HARQ feedback for the data signal; and adjust a gain applied to a signal received at a receiver (e.g., the feedback signal and / or a subsequently received signal) based on the signal. In certain aspects, the sidelink manager 122 may: receive an indication that HARQ feedback is enabled for the data signal in sidelink control information (SCI); receive the data signal; refrain from transmitting during a gap portion that occurs temporally after the reception of the data signal, wherein the gap portion has a duration less than or equal to a value; and transmit a feedback signal that includes a signal and HARQ feedback for the data signal.

[0057] According to aspects of the present disclosure, UE 120b includes a side link manager 124 , which may represent side link manager 122 .

[0058] like Figure 1 As illustrated in , the wireless communication network 100 may include several BSs 110a-z (each also individually referred to herein as BS 110, or collectively referred to as BS 110) and other network entities. BS 110 may provide communication coverage for a particular geographic area (sometimes referred to as a "cell"), which may be stationary or mobile depending on 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 1In the example shown in FIG, BSs 110a, 110b, and 110c may be macro BSs for macro cells 102a, 102b, and 102c, respectively. BS 110x may be a pico BS for pico cell 102x. BSs 110y and 110z may be femto BSs for femto cells 102y and 102z, respectively. A BS may support one or more cells.

[0059] BS 110 communicates with UEs 120a-y (each also individually referred to herein as UE 120 or collectively referred to herein as UE 120) in wireless communication network 100. UEs 120 (e.g., 120x, 120y, etc.) may be dispersed throughout wireless communication network 100, and each UE 120 may be stationary or mobile. In one example, a quadcopter, drone, or any other unmanned aerial vehicle (UAV) or remotely piloted aerial system (RPAS) 120d may be configured to serve as a UE. Wireless communication network 100 may also include a relay station (e.g., relay station 110r) (also referred to as a relay, etc.) that receives transmissions of data and / or other information from an upstream station (e.g., BS 110a or UE 120r) and sends transmissions of the data and / or other information to a downstream station (e.g., UE 120 or BS 110), or that relays transmissions between UEs 120 to facilitate communication between the devices.

[0060] The network controller 130 may communicate with a set of BSs 110 and provide coordination and control (e.g., via a backhaul) for the BSs 110. In various aspects, the network controller 130 may be in communication with a core network 132 (e.g., a 5G core network (5GC)), which provides various network functions such as access and mobility management, session management, user plane functions, policy control functions, authentication server functions, unified data management, application functions, network exposure functions, network repository functions, network slice selection functions, etc.

[0061] Figure 2 Illustrated are BS 110a and UE 120a (eg, Figure 1 Example components of a wireless communication network 100).

[0062] At BS 110a, transmit processor 220 may receive data from data source 212 and control information from controller / processor 240. The control information may be for a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical hybrid ARQ indicator channel (PHICH), a physical downlink control channel (PDCCH), a group common PDCCH (GC PDCCH), etc. The data may be for a physical downlink shared channel (PDSCH), etc. A medium access control (MAC)-control element (MAC-CE) is a MAC layer communication structure that may be used for the exchange of control commands between wireless nodes. The MAC-CE may be carried in a shared channel, such as a physical downlink shared channel (PDSCH), a physical uplink shared channel (PUSCH), or a physical sidelink shared channel (PSSCH).

[0063] Processor 220 may process (e.g., encode and symbol map) data and control information to obtain data symbols and control symbols, respectively. Transmit processor 220 may 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)). Transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, and / or reference symbols, as applicable, and may provide output symbol streams to modulators (MODs) 232a-232t. Each modulator 232 may process its respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. The downlink signals from modulators 232a-232t may be transmitted via antennas 234a-234t, respectively.

[0064] At UE 120a, antennas 252a-252r may receive downlink signals from BS 110a and may provide received signals to demodulators (DEMODs) 254a-254r, respectively, within the transceiver. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 256 may receive received symbols from all demodulators 254a-254r, perform MIMO detection on the received symbols where applicable, and provide detected symbols. A receive processor 258 may 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.

[0065] On the uplink, at UE 120a, a transmit processor 264 may receive and process data from a data source 262 (e.g., for a physical uplink shared channel (PUSCH)) and control information from a controller / processor 280 (e.g., for a physical uplink control channel (PUCCH)). The transmit processor 264 may also generate reference symbols for reference signals (e.g., a sounding reference signal (SRS)). The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266, if applicable, further processed by modulators 254a-254r in the transceiver (e.g., for SC-FDM, etc.), and transmitted to BS 110a. At BS 110a, the uplink signal from UE 120a may be received by antenna 234, processed by modulator 232, detected by MIMO detector 236, if applicable, and further processed by receive processor 238 to obtain decoded data and control information sent by UE 120a. Receive processor 238 may provide decoded data to data sink 239 and decoded control information to controller / processor 240 .

[0066] 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.

[0067] 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 used to perform the various techniques and methods described herein. Figure 2, in accordance with various aspects described herein, controller / processor 280 of UE 120a is shown having a side link manager 281, which may represent side link managers 122, 124. Although shown at the controller / processor, other components of UE 120a and BS 110a may also be used to perform the operations described herein.

[0068] 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, often referred to as tones, bins, etc. Each subcarrier can be modulated with data. Modulation symbols can be sent in the frequency domain with OFDM and in the time domain with 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 (so-called resource block (RB)) can be 12 contiguous subcarriers. The system bandwidth can also be divided into subbands. For example, a subband can cover multiple RBs. NR can support a base subcarrier spacing (SCS) of 15 kHz, and other SCSs (e.g., 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc.) can be defined relative to the base SCS.

[0069] Figure 3 is a diagram illustrating an example of a frame format 300 for NR. The transmission timeline for each of the downlink and uplink may be divided into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 ms) and may be divided into 10 subframes with indices 0 to 9, each subframe being 1 ms. Each subframe may contain a variable number of slots (e.g., 1, 2, 4, 8, 16, ... slots), depending on the SCS. Each slot may include a variable number of symbol periods (e.g., 7, 12, or 14 symbols), depending on the SCS. An index may be assigned to the symbol periods in each slot. A minislot (which may be referred to as a subslot structure) refers to a transmission time interval having a duration less than a slot (e.g., 2, 3, or 4 symbols). Each symbol in a slot may indicate a link direction (e.g., DL, UL, or flexible) for data transmission, and the link direction for each subframe may be dynamically switched. The link direction may be based on the slot format. Each time slot may include DL / UL data and DL / UL control information.In certain aspects, the feedback channel may occupy at least two symbols of a time slot of the frame format 300.

[0070] In NR, synchronization signal blocks (SSBs) are transmitted. In certain aspects, each SSB may be transmitted in a burst, 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). The SSBs include the PSS, SSS, and the two-symbol PBCH. The SSBs may be transmitted at fixed slot locations (such as Figure 3 ) is transmitted in the codeword 0-3 shown in . PSS and SSS can be used by UE 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 sweeping. Further system information (such as remaining minimum system information (RMSI), system information block (SIB), other system information (OSI)) can be transmitted on the physical downlink shared channel (PDSCH) in certain subframes. SSB can be transmitted up to 64 times, for example, up to 64 different beam directions for millimeter waves. Multiple transmissions of SSB are called SS burst sets. SSBs in an SS burst set can be transmitted in the same frequency region, while SSBs in different SS burst sets can be transmitted in different frequency regions.

[0071] Figure 4A and Figure 4B A diagrammatic representation of an example V2X system according to some aspects of the present disclosure is shown. For example, Figure 4A and Figure 4B The vehicles shown in FIG can communicate via a sidelink channel and can relay sidelink transmissions as described herein. A V2X system can be an example of a sidelink communication system discussed herein, and vehicles and other devices can be configured to communicate over a sidelink frequency channel, as discussed herein.

[0072] Figure 4A and Figure 4B The V2X system provided in [1] provides two complementary transmission modes. Figure 4A The first transmission mode (also referred to as Mode 4) shown as an example in FIG. 1 involves direct communication between participants that are adjacent to each other in a local area (e.g., also referred to as sidelink communication). Figure 4B The second transmission mode (also referred to as mode 3) shown as an 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).

[0073] Reference Figure 4A, a V2X system 400 (e.g., including vehicle-to-vehicle (V2V) communications) is illustrated with two vehicles 402, 404. A first transmission mode allows direct communication between different parties in a given geographic location. As illustrated, the vehicles may have a wireless communication link 406 (V2P) with an individual (e.g., via a UE) through a PC5 interface. Communication between vehicles 402 and 404 may also occur through a PC5 interface 408. Communication (V2I) from vehicle 402 to other highway components (e.g., highway components 410, such as traffic signals or signs) may occur in a similar manner through a PC5 interface 412. Figure 4A Each communication described in the preceding text can be bidirectional, so each element can be both a transmitter and receiver of information. The V2X system 400 can be a self-managed system implemented without the assistance of a network entity. This self-managed system can achieve improved spectrum efficiency, reduced costs, and increased reliability because no network service interruptions occur during handover operations for mobile vehicles. The V2X system can be configured to operate in licensed or unlicensed spectrum, allowing any vehicle equipped with the system to access shared frequencies and share information. This type of coordinated / shared spectrum operation allows for safe and reliable operation.

[0074] 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 via separate nodes, such as a base station (e.g., BS 110a), which transmit and receive information to and from vehicles 452 and 454 (e.g., relay information between vehicles 452 and 454). Network communications via vehicle-to-network (V2N) links 458 and 460 can be used, for example, for long-range communication between vehicles, such as for communicating the presence of a traffic incident at a distance ahead along a road or highway. Other types of communications can be sent by wireless nodes to vehicles, such as traffic flow conditions, road hazard warnings, environmental / weather reports, and service station availability, among others. Such data can be obtained from a cloud-based sharing service.

[0075] Roadside units (RSUs) may be utilized. RSUs may be used for V2I communications. In some examples, RSUs may act as forwarding nodes to extend the coverage of UEs. In some examples, RSUs may be co-located with BSs or may be self-contained. RSUs may have different classifications. For example, RSUs may be classified as 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 utilize the Uu interface. UE-type RSUs may be used to meet stringent Quality of Service (QoS) requirements by minimizing conflicts and improving reliability. UE-type RSUs may use centralized resource allocation mechanisms to allow efficient resource utilization. Critical information (e.g., such as traffic conditions, weather conditions, congestion statistics, sensor data, etc.) may be broadcast to UEs in the coverage area. Relays may rebroadcast critical information received from some UEs. UE-type RSUs may be reliable synchronization sources.

[0076] Figure 5 FIG2 is a schematic diagram illustrating an example network 500 of multiple CV2X devices operating in an unlicensed spectrum. The unlicensed spectrum can be an example of a sidelink spectrum. Furthermore, the network 500 can be an example of a sidelink communication system. The CV2X devices 502 can be configured to communicate on a sidelink frequency channel, as discussed herein. For example, any one of the CV2X devices 502 can communicate with any other of the CV2X devices 502.

[0077] In the illustrated example, seven CV2X devices (e.g., first CV2X device 502a, second CV2X device 502b, third CV2X device 502c, fourth CV2X device 502d, fifth CV2X device 502e, sixth CV2X device 502f, and seventh CV2X device 502g—collectively, CV2X devices 502) can operate in unlicensed spectrum with other non-CV2X devices (e.g., non-CV2X devices 504a-c—collectively, non-CV2X devices 504). In some examples, first CV2X device 502a, sixth CV2X device 502f, and third CV2X device 502c can be part of a convoy or platoon. In transportation, platooning or group driving is a method for driving a group of vehicles together. This is meant to increase road capacity via automated highway systems. Platooning reduces the distance between cars or trucks (such as based on SL communication).

[0078] While the examples provided illustrate six automotive CV2X devices in a traffic setting and drone or other aerial vehicle CV2X devices, it can be appreciated that the CV2X devices and environments can extend beyond these and include other wireless communication devices and environments. For example, the CV2X devices 502 may include a UE operated by a highway authority (e.g., Figure 1 The UE 120) and / or roadside unit (RSU) may be implemented on a motorcycle or a device carried by a user (e.g., a pedestrian, a cyclist, etc.), or may be implemented on another aerial vehicle (such as a helicopter).

[0079] The CV2X device 502 may include a UE (e.g., Figure 1 The UE 120 may be a device implemented on a motor vehicle or carried by a user (eg, a pedestrian, a cyclist, etc.), or implemented as a roadside unit.

[0080] In certain aspects, sidelink communications (e.g., vehicle-to-everything (V2X) communications) may occur in a time division duplex (TDD) manner. That is, a UE communicating on the sidelink both transmits and receives sidelink signals in the same carrier or frequency band, but transmits at different times than receives. When a user equipment (UE) communicates in TDD mode, in certain aspects, the UE may be scheduled to neither transmit nor receive during a period (e.g., an interstitial period, which may be an interstitial symbol) to enable the UE's hardware (e.g., radio front end) to switch from transmit (Tx) mode to receive (Rx) mode, or vice versa. In certain aspects, sidelink communications may be decoupled from synchronization, meaning they are not synchronized in time because there may not be a central unit providing synchronization. For example, a receiving UE may receive a sidelink transmission from device A (e.g., another UE) but may be synchronized with device B (e.g., another UE, a base station (BS), or a global navigation satellite system (GNSS)). Decoupling may result in a propagation delay of unknown length at the receiving UE, for example, for the sidelink transmission from device A, due to differences in synchronization sources. The gap period can accommodate such propagation delays because no content is scheduled for transmission or reception during the gap period, and the receiving UE is able to receive the delayed signal during the gap period without conflicting with other communications.

[0081] In certain aspects, such as in certain CV2X systems, the latest symbol in time in a slot may be reserved as a gap period (referred to as a gap symbol) for certain UEs, meaning that there may be no signal scheduled for transmission in the gap symbol and the UE may not be scheduled for reception in the gap symbol. The gap symbol may provide the UE with sufficient time, for example, to switch from Tx (or Rx) mode to Rx (or Tx) mode. In certain aspects, when a slot is configured with a physical sidelink feedback channel (PSFCH) resource (for hybrid automatic repeat request (HARQ) feedback), there may be two OFDM symbols reserved as a gap (see reference 1 below). Figure 6 description).

[0082] In some aspects, sidelink communications may have a near-far effect. For example, when a transmitting UE is closer to a receiving UE (e.g., 100 meters), the receiving UE receives the transmission with higher power than when the transmitting UE is farther away from the receiving UE (e.g., 1 kilometer). Therefore, the received signal power is variable across each time slot at the receiving UE. In some aspects, the first symbol in time in a time slot (or transmission) may be used for automatic gain control (AGC) training to adjust the gain used by the UE for transmission to accommodate the near-far effect. In some aspects, the receiving UE may not decode the AGC symbol, and thus the AGC symbol does not have to carry useful information. For example, in some aspects, the AGC symbol may be a copy of the next symbol transmitted in the time slot.

[0083] Figure 6 is an example transmission timeline 650 for sidelink communication. In transmission timeline 650, PSFCH resources are configured in symbol 664. UE (e.g., Figure 1 ) transmits a physical sidelink control channel (PSCCH) 652 that allocates the other symbols in slot 680 for a physical sidelink shared channel (PSSCH) 654. As previously mentioned, the UE copies OFDM symbol 660 into the symbol at 662 for use as an AGC symbol. Another UE (e.g., Figure 1 1 receives PSCCH 652 and PSSCH 654. The other UE transmits HARQ feedback regarding PSSCH 654 on the PSFCH during symbol 664. The other UE copies OFDM symbol 664 into symbol 666 for use as an AGC symbol. Both UEs refrain from transmitting during the last symbol 670 of the slot and during symbol 672 preceding (e.g., and temporally adjacent to) AGC symbol 666.

[0084] A UE may transmit a data packet (e.g., in the PSSCH) and expect HARQ feedback from one (if the data packet is sent in unicast transmission) or multiple (if the data packet is sent in multicast transmission) recipient UEs (e.g., in the PSFCH).

[0085] The receiving UE may require a minimum amount of time to decode the data transmission; in other words, the receiving UE may not be able to transmit HARQ feedback immediately following data channel reception. For example, if the receiving UE receives the data transmission in time slot n, the receiving UE may be ready to transmit HARQ feedback in a slightly later time slot n+k. However, transmitting HARQ feedback may also be subject to LBT in unlicensed spectrum. Thus, due to processing at the receiving UE, there may be a gap between the end of the PSSCH transmission and the start of the PSFCH transmission in response to the PSSCH transmission. In some cases, if the gap is greater than a threshold, the UE (e.g., the UE that transmitted the PSSCH and the UE that received the PSSCH) cannot determine that the channel is still available for HARQ feedback transmission and will therefore perform LBT; it is possible that the channel is no longer available for HARQ feedback transmission (e.g., occupied by other technologies or devices).

[0086] In some cases, the threshold of the gap may be 16 microseconds (μs), which means that the transmitting device (eg, UE) will perform LBT if the gap exceeds 16 μs. In some cases, the threshold of the gap may be different depending on the region.

[0087] Figure 7 is an example transmission timeline 700 illustrating the sidelink feedback technique described above. Timeline 700 illustrates time slots n-1 to n+k, each of which may have a time slot according to Figure 6 . In this example transmission timeline, a first UE (e.g., UE 120a in wireless communication network 100) transmits a PSSCH to a second UE (e.g., UE 120b in wireless communication network 100) in time slot 702. In time slot 704, the second UE may be scheduled to transmit feedback to the first UE, as discussed above. Because the transmission of HARQ feedback may be subject to LBT procedures, the channel may not be available for feedback transmission, which may delay retransmissions from the first UE to the second UE.

[0088] Accordingly, certain aspects provide techniques and apparatus for transmitting sidelink data transmissions and sidelink feedback for the sidelink data transmissions in a wireless communication system without requiring a receiving UE to perform LBT before transmitting the feedback.

[0089] Example Sidelink Communication for HARQ Feedback Transmission in Unlicensed Spectrum

[0090] Various aspects of the present disclosure provide techniques for sidelink communication with hybrid automatic repeat request (HARQ) feedback transmission in an unlicensed frequency band. In certain aspects of the present disclosure, a first UE may transmit a sidelink data transmission and, after a gap not greater than a threshold, receive a signal containing corresponding sidelink feedback from a second UE that received the sidelink data transmission. Similarly, a second UE may receive the sidelink data transmission, refrain from transmitting during a gap not greater than a threshold, and, after the gap, transmit a signal containing corresponding sidelink feedback information.

[0091] According to various aspects of the present disclosure, a transmitting UE transmits data in an unlicensed spectrum used for sidelink communication, and one or more receiving UEs may receive the data transmission from the transmitting UE. Various aspects of the present disclosure may provide HARQ feedback techniques that may facilitate lower latency and / or higher data rates, for example, due to the ability of the receiving UE to send HARQ feedback without performing LBT or other channel sensing.

[0092] In certain aspects of the present disclosure, if HARQ feedback is enabled (e.g., requested by a UE transmitting data via sidelink control information), a feedback signal including a signal and HARQ feedback may be transmitted after data reception (e.g., by one or more UEs receiving data); transmission of the feedback signal including the HARQ feedback may be after a gap no greater than (e.g., less than or equal to) a threshold. In some aspects, the signal may be used by the receiving UE to perform AGC and is referred to as an AGC signal. Thus, the unlicensed band is continuously occupied by UEs transmitting data (transmitting data) and UEs receiving data (transmitting HARQ feedback), and the UEs (e.g., the UEs receiving data) may transmit HARQ feedback without performing LBT or other channel sensing on the unlicensed band.

[0093] According to aspects of the present disclosure, there may be a gap between data transmissions of a UE transmitting data (e.g., a PSSCH) and transmissions of a UE receiving data (e.g., a PSFCH containing an AGC signal and HARQ feedback), as long as the gap is no greater than a threshold (e.g., 16 μs or a gap for turnaround), which may be a threshold (e.g., as specified in a wireless communication standard and / or regulations for wireless communication in an unlicensed spectrum).

[0094] In certain aspects of the present disclosure, a UE receiving data may transmit an AGC signal in a symbol (eg, referred to as an AGC symbol) that precedes (eg, and is adjacent to) a HARQ feedback transmission.

[0095] According to certain aspects of the present disclosure, an AGC signal (e.g., an AGC signal transmitted before (e.g., and adjacent to) HARQ feedback) may carry predetermined information (e.g., a configured sequence), so that the content of the AGC signal does not depend on the PSSCH decoding result, and the UE receiving data can transmit the AGC signal after (e.g., immediately) receiving the PSSCH. That is, because the UE receiving data transmits the predetermined information in the AGC signal instead of replicating the signal transmitted in the subsequent codeword (see Figure 6 ), so the UE receiving data may transmit AGC before the UE has finished decoding the PSSCH and preparing the HARQ feedback (e.g., in the PSFCH).

[0096] In certain aspects of the present disclosure, the UE receiving data may perform PSSCH decoding and PSFCH processing while the UE receiving data transmits an AGC signal.

[0097] According to aspects of the present disclosure, a UE receiving data may transmit HARQ feedback (eg, PSFCH) after AGC signal transmission.

[0098] In various aspects of the present disclosure, the gap duration is less than a threshold (e.g., 16 μs or 25 μs or another threshold, as may be specified by a regional regulator) so that a UE receiving data can access the unlicensed band and transmit feedback signals. For example, a UE receiving data can transmit an AGC signal and HARQ feedback after the gap (less than the threshold) without performing LBT.

[0099] Figure 8A and 8B800 and 850 are example transmission timelines for sidelink communications according to aspects of the present disclosure. In transmission timeline 800, HARQ feedback from a UE (e.g., UE 120a) in response to a sidelink data transmission 802 during a time slot 830 is mapped to HARQ feedback 820 in time slot 830, which may have a duration of one symbol. The UE also transmits an AGC signal 822, which may occupy less than two symbols 804 in the time slot. A gap 810 exists between the sidelink data transmission and the combination of AGC and PSFCH transmissions. That is, the UE may transmit a feedback signal 840 including HARQ feedback 820 and AGC signal 822 after gap 810. In certain aspects, the gap is no greater than a threshold (e.g., 16 μs or 25 μs) such that the UE may transmit AGC and HARQ feedback without performing LBT, as discussed above. Thus, in some aspects, the AGC signal transmission may occupy a portion of a symbol duration, such that a gap no greater than a threshold value may be accommodated before a portion of the AGC signal (e.g., the AGC symbol may have an extra-large CP length; the symbol following the data transmission may include the gap and a portion of the extra-large CP length). A total of three symbols are used for the combination of the gap, AGC, and HARQ feedback, and thus a UE receiving data has two symbols (e.g., including the gap and AGC) to perform PSSCH decoding and HARQ feedback processing. At the beginning of time slot 830, one symbol 812 may be used as another gap, as an AGC symbol, or for data transmission.

[0100] In transmission timeline 850, HARQ feedback 870 transmitted by a UE (e.g., UE 120b in wireless communication network 100) is mapped to symbol 872 in time slot 880. In this example, the UE also transmits an AGC signal 874 in symbol 866. A gap 865 exists between the sidelink data transmission 852 and the feedback signal 890, which includes the AGC signal 874 and the HARQ feedback signal 870. In some aspects, the AGC signal may occupy only a portion of a symbol, so that the gap can be at the beginning of a symbol to accommodate the AGC signal. In this example, a total of two symbols are used for the combination of the gap, the AGC signal, and the HARQ feedback, and thus the UE receiving the data has one symbol (e.g., including the gap and AGC) to perform PSSCH decoding and PSFCH processing. At the beginning of the time slot, one symbol 862 can be used as another gap, as an AGC symbol, or for data transmission.

[0101] Figure 9A and 9B900 and 950 are example transmission timelines for sidelink communications according to aspects of the present disclosure, with a gap at the end of a time slot. In transmission timeline 900, HARQ feedback 920 from a UE (e.g., UE 120a) in response to a sidelink data transmission 902 during time slot 930 is mapped to a symbol 922 in that time slot. The UE also transmits an AGC signal 924, which may occupy more than two symbols 904 in time slot 930. A gap 910 exists between the sidelink data transmission 902 and a feedback signal 940 including the AGC signal 924 and the HARQ feedback 920. In certain aspects, this gap is no greater than a threshold (e.g., 16 μs or 25 μs), allowing the UE to transmit AGC and PSFCH without performing LBT. Therefore, in certain aspects, a portion of the AGC symbol may be duplicated and transmitted earlier than symbol 904 so that the gap time is no greater than the threshold (e.g., the AGC symbol may have an extra-large cyclic prefix (CP) length). In certain aspects, a total of 3 symbols are used for the combination of slots, AGC, and HARQ feedback, and thus a UE receiving data has 2 symbols (e.g., including the slot and AGC) to perform PSSCH decoding and PSFCH processing. At the beginning of a slot, one symbol 912 can be used as another slot, as an AGC symbol, or for data transmission. Another slot can be included in the last symbol 926 of the slot.

[0102] In transmission timeline 950, HARQ feedback 970 transmitted by a UE (e.g., UE 120b in wireless communication network 100) is mapped to symbol 972 in time slot 980. The UE also transmits an AGC signal 974 in symbol 966. A gap 965 exists between the sidelink data transmission 952 and the feedback signal 990 including the AGC signal 974 and HARQ feedback 970. The AGC signal may occupy only a portion of a symbol, so the gap may be at the beginning of a symbol that accommodates an AGC symbol. A total of two symbols are used for the combination of gap, AGC, and HARQ feedback, and thus the UE receiving data has one symbol (e.g., including the gap and AGC) to perform PSSCH decoding and PSFCH processing. At the beginning of a time slot, one symbol 962 may be used as another gap, as an AGC symbol, or for data transmission. Another gap may be included in the last symbol 976 of the time slot.

[0103] although Figures 8A-8B The examples shown in FIG. 9A-9B show the combination of the gap and the AGC signal as occupying 1 symbol (e.g., Figure 8B 865 and 866 in Figure 9B 965 and 966 in ) or 2 symbols (e.g., Figure 8A 804 and 810 or Figure 9A904 and 910 in ), but the present disclosure is not limited thereto, and the combination of gaps and AGC signals may occupy other numbers N of symbols, N being greater than 2. In such cases, a portion of the N symbols may include gaps, and the remaining portion may include AGC signals.

[0104] According to various aspects of the present disclosure, HARQ feedback transmission may be enabled by a UE transmitting data. For example, the UE transmitting data may indicate a request for HARQ feedback in Sidelink Control Information (SCI).

[0105] In certain aspects of the present disclosure, if HARQ feedback is requested, a UE receiving data stops receiving from a UE transmitting data at a configured symbol. For example, another UE or a UE transmitting data provides a duration or common configuration of a data signal to a UE receiving data via an SCI, indicating the last symbol available for data transmission in a timeslot. For example, a UE receiving data may be (pre)configured or scheduled such that the last symbol used for data transmission is the 11th symbol in a timeslot (e.g., for symbols in a timeslot with a normal cyclic prefix (CP) length). If HARQ feedback is requested, the UE receiving data switches to transmit mode after the 11th symbol and then transmits an AGC signal and HARQ feedback, as previously discussed.

[0106] According to various aspects of the present disclosure, if HARQ feedback is not requested, a UE receiving data may stop receiving from a UE transmitting data at a different configured symbol (such as similarly configured via SCI). For example, if HARQ feedback is not requested, a UE receiving data may be (pre-)configured such that the last symbol used for data transmission is the 14th symbol in a slot (e.g., for a slot with a normal CP length symbol).

[0107] In certain aspects of the present disclosure, a UE receiving data knows which symbol is the last symbol in the data transmission after decoding the sidelink control signaling (eg, SCI) scheduling the data transmission, and operates accordingly.

[0108] According to certain aspects of the present disclosure, the transmission of the AGC signal is independent of information in the PSFCH or other data channels, so that the transmission of the AGC symbol does not depend on the data channel decoding results. For example, the AGC symbol may carry a predetermined sequence (e.g., a (pre-)configured low peak-to-average power ratio (low-PAPR) sequence), as discussed above.

[0109] Figure 10 1 is a flow diagram illustrating example operations 1000 for wireless communication in accordance with certain aspects of the present disclosure. Operations 1000 may be performed, for example, by a UE (e.g., UE 120a in wireless communication network 100). Operations 1000 may be implemented as a process on one or more processors (e.g., Figure 2 Furthermore, signal transmission and reception by the UE in operation 1000 may be performed by, for example, one or more antennas (e.g., Figure 2 In certain aspects, signal transmission and / or reception by the UE may be achieved by obtaining and / or outputting signals via a bus interface of one or more processors (e.g., controller / processor 280).

[0110] Operations 1000 may optionally begin at block 1002, where the UE may transmit an indication in sidelink control information (SCI) in a time slot that HARQ feedback is enabled for a data signal.

[0111] At block 1004, the UE may transmit a data signal. The data signal may include various content, such as application data, sensor data, and / or V2X data.

[0112] Operations 1000 may continue at block 1006, where the UE may refrain from transmitting during a gap portion occurring temporally after transmitting the data signal, where the gap portion has a duration less than or equal to a value (eg, a threshold).

[0113] Operations 1000 may continue at block 1008, where the UE may receive a feedback signal after the gap portion, where the feedback signal includes at least one signal and hybrid automatic repeat request (HARQ) feedback for the data signal.

[0114] In various aspects, the signal may include an AGC signal. Optionally, at block 1010, the UE may receive another signal and adjust a gain applied to the other signal (e.g., subsequent signal(s)) at the receiver based on one or more properties of the signal (e.g., received power of the signal). For example, the UE may identify that the received power of the AGC signal is high, and the UE may reduce the gain applied to signals received from the other UE that transmitted the AGC signal.

[0115] In some such aspects, the SCI further indicates a symbol during which the data signal ends, and the device may also determine another symbol for receiving the feedback signal based on the symbol. That is, the SCI may indicate a symbol during which the data signal ends, and the UE may receive the feedback signal in at least another symbol after the symbol. In other words, the SCI may indicate the duration of the data signal, and the UE may initiate refraining from transmitting based on the duration of the data signal.

[0116] In aspects of the present disclosure, the threshold of block 1006 may be one of: fixed or configurable from a set of candidate values.

[0117] According to various aspects of the present disclosure, the feedback signal of block 1006 may be received over at least three symbols (including a first symbol in time, a second symbol in time, and a third symbol in time), wherein the gap portion occurs during the first symbol, the AGC signal is received during the first and second symbols, and the HARQ feedback is received during the third symbol. In other words, at block 1008, the UE may receive the feedback signal over at least three symbols including the first symbol in time, the second symbol in time, and the third symbol in time, wherein the gap portion occurs during the first symbol. The UE may receive the signal during the first and second symbols, and receive the HARQ feedback during the third symbol.

[0118] In various aspects of the present disclosure, the feedback signal of block 1008 may be received over at least two symbols (including a first symbol in time and a second symbol in time), wherein the gap portion occurs during the first symbol, the AGC signal is received during the first symbol, and the HARQ feedback is received during the second symbol. That is, at block 1008, the UE may receive the feedback signal over at least two symbols including the first symbol in time and the second symbol in time, wherein the gap portion occurs during the first symbol. The UE may receive the signal during the first symbol and receive the HARQ feedback during the second symbol.

[0119] According to aspects of the present disclosure, the feedback signal of block 1006 may be received over a plurality of symbols including a first one or more symbols in time and a second one or more symbols in time, wherein the gap portion occurs during one of the first one or more symbols, the AGC signal is received during the first one or more symbols, and the HARQ feedback is received during the second one or more symbols. In other words, at block 1008, the UE may receive the feedback signal over a plurality of symbols including the first one or more symbols in time and the second one or more symbols in time, wherein the gap portion occurs during one of the first one or more symbols. The UE may receive the signal during the first one or more symbols and receive the HARQ feedback during the second one or more symbols.

[0120] In certain aspects, the UE may receive feedback in the same time slot in which the data signal is transmitted. For example, the UE may transmit at least a portion of the data signal in a time slot and refrain from transmitting during a gap portion of the time slot. The UE may receive the feedback signal in the time slot.

[0121] Figure 111 is a flow diagram illustrating example operations 1100 for wireless communication according to certain aspects of the present disclosure. Operations 1100 may be performed, for example, by another UE (e.g., UE 120b in wireless communication network 100). Operations 1100 may be complementary to operations 1000 performed by a UE. Operations 1100 may be implemented as a processor on one or more processors (e.g., Figure 2 Furthermore, signal transmission and reception by the UE in operation 1100 may be performed by, for example, one or more antennas (e.g., Figure 2 In some aspects, signal transmission and / or reception by the BS may be achieved by obtaining and / or outputting signals via a bus interface of one or more processors (e.g., controller / processor 280).

[0122] Operations 1100 may begin at block 1102, where the UE may receive an indication in an SCI that HARQ feedback is enabled for a data signal.

[0123] At block 1104 , the UE may receive a data signal.

[0124] Operations 1100 may continue at block 1106 where the UE may refrain from transmitting during a gap portion occurring temporally after receiving the data signal, where the gap portion has a duration less than or equal to a value (eg, a threshold).

[0125] Operations 1100 may continue at block 1108, where the UE may transmit a feedback signal including a data signal and HARQ feedback for the data signal. In various aspects, the signal may include an AGC signal. For example, the signal may cause the other UE receiving the signal to perform an automatic gain control operation, such as adjusting a gain applied to the received signal at a receiver based on one or more properties of the signal (e.g., a received power of the signal).

[0126] The UE can identify the duration of the data channel (e.g., the symbol position at which data transmission ends) so that the UE knows when to stop receiving the data signal. The SCI can indicate whether HARQ feedback transmission for the data channel is enabled, and the UE can implicitly or explicitly determine the data channel duration via the SCI. When the SCI indicates that HARQ feedback is enabled, the UE can determine the data channel duration, for example, based on a (pre-)configuration or a predetermined rule. In response to receiving the SCI, the UE can identify the gap portion and the signal portion within the time slot based on the indication that HARQ feedback is enabled. In some cases, the SCI can explicitly indicate the duration of the data channel used for the data signal. In some such aspects, the SCI further indicates the symbol during which the data signal ends, and the device performing operation 1100 can determine another symbol for transmitting the feedback signal based on the symbol. That is, the SCI can indicate the symbol in which the data signal ends, and the UE can transmit the feedback signal in at least another symbol after the symbol. In other words, the SCI may indicate the duration of the data signal, and the UE may initiate refraining from transmitting based on the duration of the data signal.

[0127] In aspects of the present disclosure, the threshold of block 1106 may be one of: fixed or configurable from a set of candidate values.

[0128] According to various aspects of the present disclosure, the feedback signal of block 1108 may be transmitted over at least three symbols (including a first symbol in time, a second symbol in time, and a third symbol in time), wherein the gap portion occurs during the first symbol, the AGC signal is transmitted during the first and second symbols, and the HARQ feedback is transmitted during the third symbol. In other words, at block 1108, the UE may transmit the feedback signal over at least three symbols including the first symbol in time, the second symbol in time, and the third symbol in time, wherein the gap portion occurs during the first symbol. The UE may transmit the signal during the first and second symbols, and transmit the HARQ feedback during the third symbol.

[0129] In various aspects of the present disclosure, the feedback signal of block 1108 may be transmitted over at least two symbols (including a first symbol in time and a second symbol in time), wherein the gap portion occurs during the first symbol, the AGC signal is transmitted during the first symbol, and the HARQ feedback is transmitted during the second symbol. That is, at block 1108, the UE may transmit the feedback signal over at least two symbols including the first symbol in time and the second symbol in time, wherein the gap portion occurs during the first symbol. The UE may transmit the signal during the first symbol and transmit the HARQ feedback during the second symbol.

[0130] According to aspects of the present disclosure, the feedback signal of block 1108 may be transmitted over a plurality of symbols including a first one or more symbols in time and a second one or more symbols in time, wherein the gap portion occurs during one of the first one or more symbols, the AGC signal is transmitted during the first one or more symbols, and the HARQ feedback is transmitted during the second one or more symbols. In other words, at block 1108, the UE may transmit the feedback signal over a plurality of symbols including the first one or more symbols in time and the second one or more symbols in time, wherein the gap portion occurs during one of the first one or more symbols. The UE may transmit the signal during the first one or more symbols and transmit the HARQ feedback during the second one or more symbols.

[0131] In aspects of the present disclosure, the AGC signal of block 1108 may include a low peak-to-average power ratio (low-PAPR) sequence.

[0132] In various aspects, the UE may transmit the feedback signal in the same time slot in which the data signal is received. For example, the UE may receive a portion of the data signal in a time slot, and the UE may refrain from transmitting during the gap portion in the time slot and transmit the feedback signal in the time slot.

[0133] Figure 12 Illustrated are operations that may include being configured to perform the techniques disclosed herein (such as Figure 10 12. The communication device 1200 includes various components (e.g., corresponding to means-plus-function components) for performing the operations illustrated in the accompanying drawings. The communication device 1200 includes a processing system 1202 coupled to a transceiver 1208 (e.g., a transmitter and / or receiver). The transceiver 1208 is configured to transmit and receive signals for the communication device 1200 (such as the various signals described herein) via an antenna 1210. The processing system 1202 can be configured to perform processing functions for the communication device 1200, including processing signals received and / or to be transmitted by the communication device 1200.

[0134] The processing system 1202 includes a processor 1204 coupled to a computer readable medium / memory 1212 via a bus 1206. In some aspects, the computer readable medium / memory 1212 is configured to store data that, when executed by the processor 1204, causes the processor 1204 to execute Figure 10In some aspects, the computer-readable medium / memory 1212 stores: code 1214 for transmitting a data signal; code 1216 for refraining from transmitting during a gap portion that occurs temporally after the transmission of the data signal, wherein the gap portion has a duration less than or equal to a threshold; code 1218 for receiving a feedback signal after the gap portion, wherein the feedback signal includes at least an automatic gain control (AGC) signal and hybrid automatic repeat request (HARQ) feedback for the data signal; code 1220 for transmitting an indication in an SCI that HARQ feedback is enabled for the data signal; and / or code 1222 for adjusting a gain applied to a received signal at a receiver based on the signal. In some aspects, the processor 1204 has circuitry configured to implement the code stored in the computer-readable medium / memory 1212. Processor 1204 includes: a circuit system 1224 for transmitting a data signal; a circuit system 1226 for suppressing transmission during a gap portion that occurs temporally after the transmission of the data signal, wherein the gap portion has a duration less than or equal to a threshold; a circuit system 1228 for receiving a feedback signal after the gap portion, wherein the feedback signal includes at least an automatic gain control (AGC) signal and a hybrid automatic repeat request (HARQ) feedback for the data signal; a circuit system 1230 for transmitting an indication in an SCI that HARQ feedback is enabled for the data signal; and / or a circuit system 1232 for adjusting a gain applied to a signal received at a receiver (e.g., transceiver 1208) based on the signal.

[0135] Figure 13 Illustrated are operations that may include being configured to perform the techniques disclosed herein (such as Figure 11 13. The communication device 1300 includes various components (e.g., corresponding to means-plus-function components) that may be used to perform the operations described herein. The communication device 1300 includes a processing system 1302 coupled to a transceiver 1308 (e.g., a transmitter and / or receiver). The transceiver 1308 is configured to transmit and receive signals for the communication device 1300 (such as the various signals described herein) via an antenna 1310. The processing system 1302 may be configured to perform processing functions for the communication device 1300, including processing signals received and / or to be transmitted by the communication device 1300.

[0136] The processing system 1302 includes a processor 1304 coupled to a computer readable medium / memory 1312 via a bus 1306. In some aspects, the computer readable medium / memory 1312 is configured to store data that, when executed by the processor 1304, causes the processor 1304 to execute Figure 11 In some aspects, the computer-readable medium / memory 1312 stores: code 1314 for receiving a data signal; code 1316 for refraining from transmitting during a gap portion that occurs temporally after receiving the data signal, wherein the gap portion has a duration less than or equal to a threshold; code 1318 for transmitting a feedback signal that includes an automatic gain control (AGC) signal and hybrid automatic repeat request (HARQ) feedback for the data signal; and / or code 1320 for receiving an indication in an SCI that HARQ feedback is enabled for the data signal. In some aspects, the processor 1304 has circuitry configured to implement the code stored in the computer-readable medium / memory 1312. Processor 1304 includes: a circuit system 1324 for receiving a data signal; a circuit system 1326 for suppressing transmission during a gap portion that occurs temporally after receiving the data signal, wherein the gap portion has a duration less than or equal to a threshold; a circuit system 1328 for transmitting a feedback signal, the feedback signal comprising an automatic gain control (AGC) signal and a hybrid automatic repeat request (HARQ) feedback for the data signal; and / or a circuit system 1330 for receiving an indication in an SCI that HARQ feedback is enabled for the data signal.

[0137] Means for transmitting (or means for outputting for transmission) may include an antenna (e.g., antennas 252a-252r), a transceiver (e.g., transceivers 254a-254r), a processor (e.g., controller / processor 280), and / or circuitry for receiving (e.g., circuitry for transmitting 1224, 1230, 1328). Means for receiving (or means for acquiring) may include an antenna (e.g., antennas 252a-252r), a transceiver (e.g., transceivers 254a-254r), a processor (e.g., controller / processor 280), and / or circuitry for receiving (e.g., circuitry for receiving 1228, 1324, 1330). Means for refraining from transmitting may include a transceiver (e.g., transceivers 254a-254r), a processor (e.g., controller / processor 280), and / or circuitry for refraining from transmitting (e.g., circuitry for refraining from transmitting 1226, 1326). Means for adjusting may include a transceiver (e.g., transceivers 254a-254r), a processor (e.g., controller / processor 280), and / or circuitry for adjusting (e.g., circuitry for adjusting 1232). In various aspects, each processor and / or each circuitry may include circuits designed to perform the functions described herein, a central processing unit (CPU), a graphics processing unit (GPU), 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 a combination thereof.

[0138] Example aspects

[0139] In addition to the above aspects, specific combinations of aspects are also within the scope of the present disclosure, some of which are described in detail below:

[0140] Aspect 1: A method for wireless communication, comprising: transmitting a data signal; suppressing transmission during a gap portion occurring temporally after transmitting the data signal, wherein the gap portion has a duration less than or equal to a value; and receiving a feedback signal after the gap portion, wherein the feedback signal includes at least an automatic gain control (AGC) signal and a hybrid automatic repeat request (HARQ) feedback for the data signal.

[0141] Aspect 2: The method of aspect 1 further comprises: transmitting an indication that HARQ feedback is enabled for the data signal in sidelink control information (SCI).

[0142] Aspect 3: The method of aspect 2, wherein the SCI further indicates a codeword, wherein the data signal ends during the codeword, and the method further includes: determining another codeword for receiving the feedback signal based on the codeword.

[0143] Aspect 4: The method of any of aspects 1-3, wherein the value is one of: fixed or configured from a set of candidate values.

[0144] Aspect 5: A method as in any one of Aspects 1-4, wherein the feedback signal is received over at least 3 codewords including a first codeword in time, a second codeword in time, and a third codeword in time, wherein the gap portion occurs during the first codeword, the AGC signal is received during the first codeword and the second codeword, and the HARQ feedback is received during the third codeword.

[0145] Aspect 6: A method as in any of Aspects 1-4, wherein the feedback signal is received over at least 2 codewords including a first codeword in time and a second codeword in time, wherein the gap portion occurs during the first codeword, the AGC signal is received during the first codeword, and the HARQ feedback is received during the second codeword.

[0146] Aspect 7: A method as in any of Aspects 1-4, wherein the feedback signal is received over a plurality of symbols including a first one or more symbols in time and a second one or more symbols in time, wherein the gap portion occurs during one of the first one or more symbols, the AGC signal is received during the first one or more symbols, and the HARQ feedback is received during the second one or more symbols.

[0147] Aspect 8: A method for wireless communication, comprising: receiving a data signal; suppressing transmission during a gap portion that occurs in time after receiving the data signal, wherein the gap portion has a duration less than or equal to a value; and transmitting a feedback signal, the feedback signal comprising an automatic gain control (AGC) signal and a hybrid automatic repeat request (HARQ) feedback for the data signal.

[0148] Aspect 9: The method of aspect 8, further comprising: receiving an indication in sidelink control information (SCI) that HARQ feedback is enabled for the data signal.

[0149] Aspect 10: The method of aspect 9, wherein the SCI further indicates a codeword, wherein the data signal ends during the codeword, and the method further comprises: determining another codeword for transmitting the feedback signal based on the codeword.

[0150] Aspect 11: The method of any of aspects 8-10, wherein the value is one of: fixed or configured from a set of candidate values.

[0151] Aspect 12: A method as in any of Aspects 8-11, wherein the feedback signal is transmitted over at least 3 codewords including a first codeword in time, a second codeword in time, and a third codeword in time, wherein the gap portion occurs during the first codeword, the AGC signal is transmitted during the first codeword and the second codeword, and the HARQ feedback is transmitted during the third codeword.

[0152] Aspect 13: A method as in any of Aspects 8-11, wherein the feedback signal is transmitted over at least 2 codewords including a first codeword in time and a second codeword in time, wherein the gap portion occurs during the first codeword, the AGC signal is transmitted during the first codeword, and the HARQ feedback is transmitted during the second codeword.

[0153] Aspect 14: A method as in any of Aspects 8-11, wherein the feedback signal is transmitted over a plurality of codewords including a first one or more codewords in time and a second one or more codewords in time, wherein the gap portion occurs during one of the first one or more codewords, the AGC signal is transmitted during the first one or more codewords, and the HARQ feedback is transmitted during the second one or more codewords.

[0154] Aspect 15: The method of any one of aspects 8-14, wherein the AGC signal comprises a low peak-to-average power ratio (low-PAPR) sequence.

[0155] Aspect 16: An apparatus for wireless communication, comprising means for performing the method according to any one of aspects 1-15 or 35-48.

[0156] Aspect 17: An apparatus for wireless communication, comprising: a memory; and a processor coupled to the memory, the memory and the processor configured to perform the method according to any one of aspects 1-15 or 35-48.

[0157] Aspect 18: A computer-readable medium comprising instructions that, when executed by a processing system, cause the processing system to perform the method according to any one of aspects 1-15 or 35-48.

[0158] Aspect 19: An apparatus for wireless communication, comprising: a memory; and a processor coupled to the memory, the processor and the memory being configured to: transmit a data signal, and suppress transmission during a gap portion that occurs temporally after the transmission of the data signal, wherein the gap portion has a time duration that is less than or equal to a threshold, receive a feedback signal after the gap portion, wherein the feedback signal includes at least one signal and a hybrid automatic repeat request (HARQ) feedback for the data signal, receive another signal, and adjust a gain applied to the other signal based on the signal.

[0159] Aspect 20: The apparatus of aspect 19, wherein the processor and the memory are further configured to: transmit an indication that HARQ feedback is enabled for the data signal in sidelink control information (SCI).

[0160] Aspect 21: The apparatus of aspect 20, wherein: the SCI further indicates a time duration of the data signal; and the processor and the memory are configured to: initiate refraining from transmitting at a time based on the time duration of the data signal.

[0161] Aspect 22: The apparatus according to any one of aspects 19-21, wherein the threshold is one of: fixed or configured from a set of candidate values.

[0162] Aspect 23: An apparatus according to any one of Aspects 19-22, wherein the processor and the memory are configured to: receive the feedback signal on at least 3 codewords including a first codeword in time, a second codeword in time, and a third codeword in time, wherein the gap portion occurs during the first codeword, and the signal is received during the first codeword and the second codeword, and the HARQ feedback is received during the third codeword.

[0163] Aspect 24: An apparatus according to any one of Aspects 19-22, wherein the processor and the memory are configured to: receive the feedback signal over at least 2 codewords including a first codeword in time and a second codeword in time, wherein the gap portion occurs during the first codeword, and the signal is received during the first codeword, and the HARQ feedback is received during the second codeword.

[0164] Aspect 25: An apparatus according to any one of Aspects 19-22, wherein the processor and the memory are configured to: receive the feedback signal over a plurality of codewords including a first one or more codewords in time and a second one or more codewords in time, wherein the gap portion occurs during one of the first one or more codewords, and receive the signal during the first one or more codewords, and receive the HARQ feedback during the second one or more codewords.

[0165] Aspect 26: The apparatus of any one of aspects 19-25, wherein the processor and the memory are configured to: transmit a portion of the data signal in a time slot and refrain from transmitting during the gap portion in the time slot; and receive the feedback signal in the time slot.

[0166] Aspect 27: An apparatus for wireless communication, comprising: a memory; a processor coupled to the memory, the processor and the memory being configured to: receive an indication in sidelink control information (SCI) that hybrid automatic repeat request (HARQ) feedback is enabled for a data signal, receive the data signal, suppress transmission during a gap portion that occurs temporally after receiving the data signal, wherein the gap portion has a time duration less than or equal to a threshold, and transmit a feedback signal after the gap portion, the feedback signal comprising a signal and HARQ feedback for the data signal.

[0167] Aspect 28: The apparatus of aspect 27, wherein: the SCI further indicates a time duration of the data signal; and the processor and the memory are configured to: initiate refraining from transmitting at a time based on the time duration of the data signal.

[0168] Aspect 29: The apparatus according to any one of aspects 27 or 28, wherein the threshold is one of: fixed or configured from a set of candidate values.

[0169] Aspect 30: An apparatus according to any one of Aspects 27-29, wherein the processor and the memory are configured to: transmit the feedback signal over at least 3 codewords including a first codeword in time, a second codeword in time, and a third codeword in time, wherein the gap portion occurs during the first codeword, and wherein the processor and the memory are configured to transmit the signal during the first codeword and the second codeword, and transmit the HARQ feedback during the third codeword.

[0170] Aspect 31: An apparatus according to any one of Aspects 27-29, wherein the processor and the memory are configured to: transmit the feedback signal over at least 2 codewords including a first codeword in time and a second codeword in time, wherein the gap portion occurs during the first codeword, and wherein the processor and the memory are configured to transmit the signal during the first codeword and transmit the HARQ feedback during the second codeword.

[0171] Aspect 32: An apparatus as in Aspect 27, wherein the processor and the memory are configured to: transmit the feedback signal over a plurality of codewords comprising a first one or more codewords in time and a second one or more codewords in time, wherein the gap portion occurs during one of the first one or more codewords, and wherein the processor and the memory are configured to transmit the signal during the first one or more codewords and transmit the HARQ feedback during the second one or more codewords.

[0172] Aspect 33: The apparatus of aspect 27, wherein the signal comprises a low peak-to-average power ratio (low-PAPR) sequence.

[0173] Aspect 34: An apparatus as in Aspect 27, wherein: the processor and the memory are configured to: receive a portion of the data signal in a time slot, and suppress transmission during the gap portion in the time slot and transmit the feedback signal in the time slot; and the signal is an automatic gain control (AGC) signal.

[0174] Aspect 35: A method for wireless communication, comprising: transmitting a data signal; suppressing transmission during a gap portion that occurs temporally after transmitting the data signal, wherein the gap portion has a duration less than or equal to a threshold; receiving a feedback signal after the gap portion, wherein the feedback signal includes at least one signal and a hybrid automatic repeat request (HARQ) feedback for the data signal; receiving another signal; and adjusting a gain applied to the other signal based on the signal.

[0175] Aspect 36: The method of aspect 35, further comprising: transmitting an indication that HARQ feedback is enabled for the data signal in sidelink control information (SCI).

[0176] Aspect 37: The method of aspect 36, wherein: the SCI further indicates a duration of the data signal, and refraining from transmitting comprises initiating refraining from transmitting based on the duration of the data signal.

[0177] Aspect 38: The method according to any one of aspects 35-37, wherein the threshold is one of: fixed or configured from a set of candidate values.

[0178] Aspect 39: A method according to any one of Aspects 35-38, wherein receiving the feedback signal includes receiving the feedback signal over at least 3 codewords including a first codeword in time, a second codeword in time, and a third codeword in time, wherein the gap portion occurs during the first codeword; and receiving the feedback signal further includes receiving the signal during the first codeword and the second codeword, and receiving the HARQ feedback during the third codeword.

[0179] Aspect 40: A method according to any one of Aspects 35-38, wherein receiving the feedback signal includes receiving the feedback signal over at least 2 codewords including a first codeword in time and a second codeword in time, wherein the gap portion occurs during the first codeword; and receiving the feedback signal further includes receiving the signal during the first codeword and receiving the HARQ feedback during the second codeword.

[0180] Aspect 41: A method according to any one of Aspects 35-38, wherein receiving the feedback signal includes receiving the feedback signal over a plurality of codewords including a first one or more codewords in time and a second one or more codewords in time, wherein the gap portion occurs during one of the first one or more codewords, and receiving the feedback signal further includes receiving the signal during the first one or more codewords and receiving the HARQ feedback during the second one or more codewords.

[0181] Aspect 42: A method for wireless communication, comprising: receiving an indication in sidelink control information (SCI) that hybrid automatic repeat request (HARQ) feedback is enabled for a data signal; receiving the data signal; suppressing transmission during a gap portion that occurs in time after receiving the data signal, wherein the gap portion has a duration less than or equal to a threshold; and transmitting a feedback signal, the feedback signal comprising a signal and HARQ feedback for the data signal.

[0182] Aspect 43: The method of aspect 42, wherein: the SCI further indicates the codeword in which the data signal ends, and the method further includes transmitting the feedback signal in at least another codeword after the codeword.

[0183] Aspect 44: The method according to any one of Aspects 42 or 43, wherein the threshold is one of: fixed or configured from a set of candidate values.

[0184] Aspect 45: A method according to any one of Aspects 42-44, wherein transmitting the feedback signal includes transmitting the feedback signal over at least 3 codewords including a first codeword in time, a second codeword in time, and a third codeword in time, wherein the gap portion occurs during the first codeword; and transmitting the feedback signal further includes transmitting the signal during the first codeword and the second codeword, and transmitting the HARQ feedback during the third codeword.

[0185] Aspect 46: A method according to any one of Aspects 42-44, wherein transmitting the feedback signal includes transmitting the feedback signal over at least 2 codewords including a first codeword in time and a second codeword in time, wherein the gap portion occurs during the first codeword; and transmitting the feedback signal further includes transmitting the signal during the first codeword and transmitting the HARQ feedback during the second codeword.

[0186] Aspect 47: A method according to any of Aspects 42-44, wherein transmitting the feedback signal includes transmitting the feedback signal over a plurality of codewords including a first one or more codewords in time and a second one or more codewords in time, wherein the gap portion occurs during one of the first one or more codewords; and transmitting the feedback signal further includes transmitting the signal during the first one or more codewords and transmitting the HARQ feedback during the second one or more codewords.

[0187] Aspect 48: The method according to any one of aspects 42-47, wherein the signal comprises a low peak-to-average power ratio (low-PAPR) sequence.

[0188] Additional considerations

[0189] The techniques described herein may 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 may implement radio technologies such as Universal Terrestrial Radio Access (UTRA) and cdma2000. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95, and IS-856 standards. A TDMA network may 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 others. UTRA and E-UTRA are parts 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.

[0190] 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 (BS), next-generation Node B (gNB or g-Node B), access point (AP), distributed unit (DU), carrier, or transmit reception point (TRP) can be used interchangeably. A BS can provide communication coverage for macro cells, pico cells, femto cells, and / or other types of cells. A macro cell can cover a relatively large geographic area (e.g., several kilometers in radius) and can allow unrestricted access by UEs with service subscriptions. A pico cell can cover a relatively small geographic area and can allow unrestricted access by UEs with service subscriptions. A femto cell can cover a relatively small geographic area (e.g., a residence) and can allow restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in a residence, etc.). A BS for a macro cell can be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS.

[0191] 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 equipment, 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, industrial manufacturing equipment, a global positioning system device, or any other suitable device configured to communicate via a wireless or wired medium. Some UEs may be considered machine type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., which can communicate with a base station, another device (e.g., a remote device), or some other entity. A wireless node can provide connectivity to or to a network (e.g., a wide area network (such as the Internet) or a cellular network) via, for example, a wired or wireless communication link. Some UEs may be considered Internet of Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

[0192] In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication between some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communications, the subordinate entities utilize the resources allocated by the scheduling entity. The base station is not the only entity that can be used as a scheduling entity. In some examples, a UE may act as a scheduling entity and may schedule resources for one or more subordinate entities (e.g., one or more other UEs), and other UEs may utilize the resources scheduled by the UE for wireless communication. In some examples, a UE may act as a scheduling entity in a peer-to-peer (P2P) network and / or in a mesh network. In the mesh network example, UEs may communicate directly with each other in addition to communicating with the scheduling entity.

[0193] Each method disclosed herein includes one or more steps or actions for implementing the method. These method steps and / or actions may be interchangeable with one another 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.

[0194] As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items, including single members. As an example, "at least one of a, b, or c" is intended to encompass: a, b, c, ab, ac, bc, and abc, as well as any combination with multiples of the same elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0195] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, searching (e.g., searching in a table, database, or another data structure), ascertaining, and the like. Furthermore, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. Furthermore, "determining" may include resolving, selecting, choosing, establishing, and the like.

[0196] The preceding description is provided to enable anyone skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the universal principles defined herein may be applied to other aspects. Accordingly, the claims are not intended to be limited to the aspects shown herein, but rather should be granted the full scope consistent with the claim language, wherein singular references to elements are not intended to mean "one and only one" (unless specifically stated otherwise) but rather "one or more." Unless specifically stated otherwise, the term "some" refers to one or more. All structural and functional equivalents of the various aspects described throughout this disclosure that are currently or hereafter 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 stated in the claims. No element of a claim should be interpreted 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 element is recited using the phrase "step for..."

[0197] The various operations of the methods described above may be performed by any suitable device capable of performing the corresponding functions. These devices may include various hardware and / or software components and / or modules, including but not limited to circuits, application specific integrated circuits (ASICs), or processors. Generally, where there are operations illustrated in the figures, these operations may have corresponding counterpart means-plus-function components with similar numbering.

[0198] 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 in the alternative, 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 conjunction with a DSP core, or any other such configuration.

[0199] If implemented in hardware, an example hardware configuration may include a processing system in a wireless node. The processing system may be implemented using a bus architecture. Depending on the specific application and overall design constraints of the processing system, the bus may include any number of interconnecting buses and bridges. The bus may link together various circuits including a processor, a machine-readable medium, and a bus interface. The bus interface may be used to connect a network adapter, etc., to the processing system via the bus. The network adapter may be used to implement signal processing functions at the PHY layer. In a user terminal (see Figure 1 ), a user interface (e.g., a keypad, 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, and the like, 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 circuitry capable of executing software. Those skilled in the art will recognize how to best implement the functionality described with respect to the processing system, depending on the specific application and the overall design constraints imposed on the overall network or system.

[0200] If implemented in software, each function may be stored as one or more instructions or codes on or transmitted via a computer-readable medium. Software should be broadly interpreted to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media includes both computer storage media and communication media, including any media 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. A computer-readable storage medium may be coupled to the processor so that the processor can read and write information from / to the storage medium. In an alternative embodiment, the storage medium may be integrated into the processor. As an example, the machine-readable medium may include a transmission line, a carrier modulated by data, and / or a computer-readable storage medium having instructions stored thereon that is separate from the wireless node, all of which may be accessed by the processor via a bus interface. Alternatively or additionally, the machine-readable medium or any portion thereof may be integrated into the processor, such as a cache and / or general register file. As examples, examples of machine-readable storage media may include RAM (random access memory), flash memory, ROM (read-only memory), PROM (programmable read-only memory), EPROM (erasable programmable read-only memory), EEPROM (electrically erasable programmable read-only memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage media, or any combination thereof. Machine-readable media may be embodied in a computer program product.

[0201] A software module may include a single instruction or many instructions and may be distributed across several different code segments, between different programs, and across multiple storage media. A computer-readable medium may include multiple software modules. These software modules include instructions that, when executed by a device (such as a processor), cause a processing system to perform various functions. These software modules may include a transmitting module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices. As an example, when a triggering event occurs, a software module may be loaded from a hard drive into RAM. During the execution of a software module, the processor may load some instructions into a cache to increase access speed. One or more cache lines may then be loaded into a general register file for execution by the processor. When describing the functionality of a software module below, it will be understood that such functionality is implemented by the processor when the processor executes instructions from the software module.

[0202] Likewise, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies (such as infrared (IR), radio, and microwave), then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies (such as infrared, radio, and microwave) are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Disks typically reproduce data magnetically, while discs reproduce data optically using lasers. Thus, in some aspects, computer-readable media may include non-transitory computer-readable media (e.g., tangible media). Additionally, for other aspects, computer-readable media may include transient computer-readable media (e.g., signals). Combinations of the above should also be included within the scope of computer-readable media.

[0203] 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, such as for performing the operations described herein and in Figure 10 and / or Figure 11 Instructions for the operations explained in .

[0204] In addition, it should be appreciated that the modules and / or other appropriate means for performing the methods and techniques described herein can be downloaded and / or otherwise obtained by the user terminal and / or base station where applicable. For example, such a device can be coupled to a server to facilitate the transfer of the means 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 floppy disk, etc.) so that once the storage device is coupled to or provided to the user terminal and / or base station, the device can obtain the various methods. In addition, any other suitable technology suitable for providing the methods and techniques described herein to a device can be utilized.

[0205] It will be understood that the claims are not limited to the precise configuration and components illustrated above. Various changes, substitutions 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. An apparatus for wireless communication, comprising: Memory; as well as a processor coupled to the memory, the processor and the memory being configured to: transmit data signals, and suppressing transmission during a gap portion occurring in time after transmission of the data signal, wherein the gap portion has a time duration less than or equal to a threshold value, receiving a feedback signal after the gap portion, wherein the feedback signal includes at least one signal and a hybrid automatic repeat request (HARQ) feedback for the data signal, receiving another signal, and A gain applied to the other signal is adjusted based on the signal.

2. An apparatus for wireless communication, comprising: Memory; as well as a processor coupled to the memory, the processor and the memory being configured to: receiving an indication in sidelink control information (SCI) that hybrid automatic repeat request (HARQ) feedback is enabled for the data signal, receiving the data signal, refraining from transmitting during a gap portion occurring in time after receipt of the data signal, wherein the gap portion has a time duration less than or equal to a threshold, and A feedback signal is transmitted after the gap portion, where the feedback signal includes a signal and HARQ feedback for the data signal.

3. A method for wireless communication, comprising: Transmitting data signals; refraining from transmitting during a gap portion occurring in time after transmitting the data signal, wherein the gap portion has a duration less than or equal to a threshold; receiving a feedback signal after the gap portion, wherein the feedback signal comprises at least one signal and a hybrid automatic repeat request (HARQ) feedback for the data signal; receiving another signal; and A gain applied to the other signal is adjusted based on the signal.

4. A method for wireless communication, comprising: receiving an indication in sidelink control information (SCI) that hybrid automatic repeat request (HARQ) feedback is enabled for the data signal; receiving the data signal; refraining from transmitting during a gap portion occurring in time after receipt of the data signal, wherein the gap portion has a duration less than or equal to a threshold; as well as A feedback signal is transmitted, wherein the feedback signal includes a signal and HARQ feedback for the data signal.

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