Physical Sidelink Feedback Channel (PSFCH) range extension with long PSFCH format

Abstract

Provided herein are embodiments of apparatuses, systems, and methods for performing vehicle-to-everything (V2X) sidelink communications utilizing hybrid automatic repeat request (HARQ) feedback, including using a new long physical sidelink feedback channel (PFSCH) format, namely, PFSCH format 1, to allocate feedback resources for various sidelink communication networks and environments, where existing or legacy sidelink feedback formats, namely, short PFSCH formats, referred to herein as PFSCH format 0, are insufficient to support valid acknowledgements (ACKs) and non-acknowledgements (NACKs) due to the limited nature of the format design.

Description

Technical Field

[0001] The present application relates to wireless devices, and more particularly to apparatus, systems, and methods for wireless devices to perform sidelink communications in vehicle-to-everything (V2X) wireless cellular communications and other possible Internet of Things (IoT) use cases.

[0002] Related technical description

[0003] The use of wireless communication systems is growing rapidly. One proposed use of wireless communication is in vehicular applications, particularly in V2X (Vehicle-to-Everything) systems. V2X systems allow communication between vehicles (e.g., via communication devices housed in or otherwise carried by the vehicle), pedestrian UEs (including UEs carried by other persons such as cyclists, etc.), and other wireless communication devices for various purposes such as coordinating traffic movements, facilitating autonomous driving, and performing collision avoidance. As part of V2X standardization in 3GPP and New Radio (NR), direct communication between two user equipments (UEs) without signal relaying through a centralized base station has become increasingly important. This may also be referred to as device-to-device (D2D) or peer-to-peer (P2P) communication. 3GPP sidelink transmissions have proven important for public safety and vehicle-to-everything (V2X) services in Long Term Evolution (LTE) Advanced (LTE-A). Following this successful development in LTE-A, the evolution of sidelink transmission continues in 3GPP New Radio (NR), making sidelink communication an inevitable component in addition to the more traditional cellular topology of downlink and uplink communication with the base station. The goal of the sidelink is to provide low-latency, high-reliability, and high-throughput V2X services for advanced driving use cases. Many new sidelink features not provided in LTE-A are supported in NR, including feedback channels, unauthorized access, enhanced channel sensing procedures, and new control channel designs. Therefore, improvements are needed in the areas that support this development and design. Summary of the Invention

[0004] Embodiments of apparatus, systems, and methods for performing sidelink wireless cellular communications utilizing an enhanced physical sidelink feedback channel to improve coverage are presented herein.

[0005] It is noteworthy that various embodiments of the present invention relate to technologies for enhancing sidelink wireless communications in direct communications between two user equipments (UEs) without the need for signal relaying through a base station. In 3GPP New Radio (NR), the evolution of sidelink transmission continues. As described above, many new sidelink functions not provided in LTE-A are supported in NR, including feedback channels, unauthorized access, enhanced channel sensing procedures, and new control channel designs. In order to fully understand these new functions, the embodiments disclosed herein relate to 3GPP NR sidelink transmission, including physical layer structure, resource allocation mechanism, resource sensing and selection process, synchronization, and quality of service (QoS) management. In addition, the embodiments consider enhancements to the new control channel design. Since NR sidelink transmission is already considered to be the basis for providing advanced services in addition to V2X in future releases (e.g., advanced relaying), possible enhancements are also discussed to serve urgent needs in this ongoing work.

[0006] Transmissions on the sidelink component carriers can be independently acknowledged by the receiving UE using an acknowledgement or negative acknowledgement (ACK / NACK) message in the response. This is commonly referred to as Hybrid Automatic Repeat Request (HARQ) in LTE and NR, where the transport block of data being received is acknowledged on each component carrier by transmitting one or two bits on the return link to the transmitting device. Without spatial multiplexing, there is only a single transport block within a transmission time interval (TTI), and therefore only a single acknowledgment bit is required in the response. However, if the transmission uses spatial multiplexing, there are two transport blocks per TTI, each requiring its own Hybrid-ARQ acknowledgment bit. The total number of bits required for Hybrid-ARQ acknowledgment therefore depends on the number of component carriers and the transmission mode of each of them. Since each sidelink component carrier is scheduled separately from its own PSCCH, the Hybrid-ARQ process number is signaled independently for each component carrier on a designated area of the Physical Sidelink Feedback Channel (PSFCH). In NR, only a basic acknowledgment format, called "Format 0" or Short Acknowledgment Format (PSFCH), currently exists. This non-adaptive static format is not sufficient to accommodate all the various types of networking using sidelink communications that a UE may encounter. Furthermore, the static format may cause problems in segmentation and collisions of retransmissions, so a more adaptive variable format is desired to express ACK / NACK.

[0007] Embodiments may involve a wireless device, such as a UE, that can configure radio resources for a physical sidelink feedback channel (PSFCH) to transmit an acknowledgement (ACK) or a negative acknowledgement (NACK) message on the sidelink feedback channel using a "long" PSFCH format resource configuration. The wireless device can allocate frequency resources for the long PSFCH format from one of the following: a) the remaining unused physical resource blocks (PRBs) of a resource pool used for sidelink transmissions of the physical sidelink control channel (PSCCH) and the physical sidelink shared channel (PSSCH); b) the last several subchannels of the resource pool; or c) both the high and low PRBs of the resource pool. The long PSFCH format may be referred to as PSFCH format 1 and may include 1 or 2 bits of information regarding HARQ ACK. Furthermore, PSFCH format 1 may fit into a single slot of a radio frame in the time domain and one PRB in the frequency domain.

[0008] The wireless device may also determine resource mapping between the PSSCH and long PSFCH format configurations in various ways. For example, when the number of PSSCH subchannels is equal to the number of PSFCHs in a timeslot, a one-to-one mapping may be used in the frequency domain such that when the PSSCH uses the i-th subchannel, the i-th PSFCH is used for hybrid automatic repeat request (HARQ) feedback. Furthermore, when the number of PSSCH subchannels is not equal to the number of PSFCHs in a timeslot, the wireless device may index the PSFCH resources by one of frequency first, time second, time first, frequency second, or frequency first, time second, and code third.

[0009] The wireless device may be further operable to determine that the long PSFCH format should be used by various signaling in sidelink control information (SCI) present in a sidelink control channel (PSCCH) and possible measurements of signals received by the wireless device.

[0010] In some implementations, PSFCH format 1 is dedicated for resource configuration.

[0011] The wireless device may also jointly configure PSFCH format 1 resources and PSFCH format 0 resources in the same resource pool used for sidelink transmissions of the physical sidelink control channel (PSCCH) and the physical sidelink shared channel (PSSCH).

[0012] Note that the techniques described herein may be implemented in and / or used with a number of different types of devices, including but not limited to base stations, access points, cellular telephones, portable media players, tablets, wearable devices, and various other computing devices.

[0013] This summary is intended to provide a brief overview of some of the subject matter described in this document. Therefore, it should be understood that the above-described features are merely examples and should not be construed as narrowing the scope or spirit of the subject matter described herein in any way. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following detailed description, accompanying drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] A better understanding of the present subject matter may be obtained when the following detailed description of various embodiments is considered in conjunction with the following drawings, in which:

[0015] Figure 1 illustrates an exemplary vehicle-to-everything (V2X) communication system according to some embodiments;

[0016] Figure 2 shows a base station in communication with a user equipment (UE) device according to some embodiments;

[0017] Figure 3 is an exemplary block diagram of a UE according to some embodiments;

[0018] Figure 4 is an exemplary block diagram of a base station according to some embodiments;

[0019] Figure 5 and Figure 6 shows an exemplary embodiment of allocating resources of a resource pool for an exemplary new "Long Physical Sidelink Feedback Channel (PSFCH) format" according to various embodiments;

[0020] Figure 7 and Figure 8 shows an exemplary configuration of resource allocation for a sideband feedback channel according to other embodiments;

[0021] Figure 9 shows exemplary radio slot contents for a long PSFCH format according to various embodiments;

[0022] Figure 10 An exemplary one-to-one resource mapping between PSSCH subchannels and PSFCH format 1 slots is shown for a time interval with 3 slots;

[0023] Figure 11 An exemplary embodiment of PSFCH indexing when the number of subchannels of the PSSCH is not equal to the number of PSFCHs in a time slot is shown; and

[0024] Figure 12 An exemplary implementation of spectrum sensing for determining PSFCH in Mode 2 is shown.

[0025] While the features described herein are susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and described in detail herein. It should be understood, however, that the drawings and detailed description thereof are not intended to limit this disclosure to the particular forms disclosed, but on the contrary, are intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter as defined by the appended claims. DETAILED DESCRIPTION

[0026] the term

[0027] The following is a glossary of terms used in this disclosure:

[0028] Memory medium—any of various types of non-transitory memory devices or storage devices. The term "memory medium" is intended to include installation media, such as CD-ROMs, floppy disks, or tape devices; computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; non-volatile memory such as flash memory, magnetic media, such as hard drives or optical storage devices; registers or other similar types of memory elements, etc. Memory media may also include other types of non-transitory memory or combinations thereof. In addition, the memory medium may be located in the first computer system executing the program, or may be located in a different second computer system connected to the first computer system via a network such as the Internet. In the latter case, the second computer system may provide program instructions to the first computer for execution. The term "memory medium" may include two or more memory media that may reside in different locations in different computer systems connected, for example, via a network. The memory medium may store program instructions (e.g., represented as a computer program) that can be executed by one or more processors.

[0029] Programmable hardware elements—include various hardware devices that include multiple programmable function blocks connected via programmable interconnects. Examples include FPGAs (field programmable gate arrays), PLDs (programmable logic devices), FPOAs (field programmable object arrays), and CPLDs (complex PLDs). Programmable function blocks can range from fine-grained (combinational logic units or lookup tables) to coarse-grained (arithmetic logic units or processor cores). Programmable hardware elements may also be referred to as "configurable logic units."

[0030] Computer system—any of various types of computing or processing systems, including a personal computer system (PC), mainframe computer system, workstation, network appliance, Internet appliance, personal digital assistant (PDA), television system, grid computing system, or other device or combination of devices. In general, the term "computer system" can be broadly defined to encompass any device (or combination of devices) having at least one processor that executes instructions from a memory medium.

[0031] User Equipment—as used herein, generally refers in the context of a V2X system to devices associated with movable participants or traffic participants in the V2X system, i.e., movable (capable of moving) communication devices such as vehicles and pedestrian user equipment (PUE) devices, rather than infrastructure equipment such as base stations, roadside units (RSUs), and servers.

[0032] Infrastructure equipment—As used herein, this term generally refers to certain devices in a V2X system that are not user equipment (UE) and are not carried by traffic participants (i.e., pedestrians, vehicles, or other mobile users) but facilitate user equipment participation in the V2X network. Infrastructure equipment includes base stations and roadside units (RSUs).

[0033] User Equipment (UE) (or "UE device") - any of various types of computer systems or devices that are mobile or portable and that perform wireless communication. Examples of UE devices include mobile phones or smartphones (e.g., iPhones, TM , based on Android TM phones), portable gaming devices (e.g., Nintendo DS TM PlayStation Portable TM 、Gameboy Advance TM , iPhone TM ), laptops, wearable devices (e.g., smart watches, smart glasses), PDAs, portable Internet devices, music players, data storage devices or other handheld devices, etc. In general, the term "UE" or "UE device" can be broadly defined to cover any electronic device, computing device and / or telecommunication device (or combination of devices) that can be easily transported by a user and capable of wireless communication.

[0034] Pedestrian UE (PUE) devices—User Equipment (UE) devices considered in the context of V2X systems that may be worn or carried by various persons, including not only pedestrians in the strict sense of people walking near roads, but also certain other peripheral or secondary participants or potential participants in the traffic environment. These include stationary persons, persons not in vehicles and who may not necessarily be near traffic or roads, persons jogging, running, skating, etc., or persons in vehicles (such as bicycles, scooters, or certain motor vehicles) that may not substantially support the power capabilities of a UE.

[0035] Base Station—The term “base station” has the full breadth of its ordinary meaning and includes at least a wireless communication station that is installed at a fixed location and used to communicate as part of a wireless telephone system or radio system.

[0036] Processing element (or processor)—refers to any element or combination of elements capable of performing functions in a device such as user equipment or a cellular network device. Processing elements include, for example, a processor and associated memory, portions or circuits of individual processor cores, entire processor cores, individual processors, circuits such as ASICs (application-specific integrated circuits), programmable hardware elements such as field-programmable gate arrays (FPGAs), and any of the above combinations.

[0037] Channel - the medium used to transmit information from a sender (transmitter) to a receiver. It should be noted that since the characteristics of the term "channel" may vary according to different wireless protocols, the term "channel" as used in the present invention may be considered to be used in a manner that is consistent with the standard of the type of device to which the term is used. In some standards, the channel width may be variable (e.g., depending on device capabilities, frequency band conditions, etc.). For example, LTE may support scalable channel bandwidths of 1.4 MHz to 20 MHz. In contrast, a WLAN channel may be 22 MHz wide, while a Bluetooth channel may be 1 MHz wide. Other protocols and standards may include different definitions of channels. In addition, some standards may define and use multiple types of channels, such as different channels for uplink or downlink and / or different channels for different purposes such as data, control information, etc.

[0038] Configured to—Various components may be described as being “configured to” perform one or more tasks. In such contexts, “configured to” is a broad statement that generally means “having the structure” to perform one or more tasks during operation. Thus, a component can be configured to perform a task even when the component is not currently performing the task (e.g., a set of electrical conductors can be configured to electrically connect a module to another module even when the two modules are not connected). In some contexts, “configured to” can be a broad statement that generally means “having the circuitry” to perform one or more tasks during operation. Thus, a component can be configured to perform a task even when the component is not currently turned on. Generally, the circuitry that forms the structure corresponding to “configured to” may include hardware circuitry.

[0039] For ease of description, various components may be described as performing one or more tasks. Such descriptions should be interpreted as including the phrase "configured to." Representing a component as being configured to perform one or more tasks expressly does not invoke the sixth paragraph of section 112 of title 35 of the United States Code for that component.

[0040] V2X communication system

[0041] Figure 1 An exemplary vehicle-to-everything (V2X) communication system is shown in accordance with some embodiments. Note that Figure 1 The system is only one example of a possible system, and features of the present disclosure may be implemented in any of a variety of systems as desired.

[0042] A vehicle-to-everything (V2X) communication system can be characterized as a network in which vehicles, UEs, and / or other devices and network entities exchange communications to coordinate traffic activities and other possible purposes. V2X communications include communications transmitted between vehicles (e.g., wireless devices or communication devices that form part of, are contained in, or are otherwise carried by a vehicle) and various other devices. V2X communications include vehicle-to-pedestrian (V2P) communications, vehicle-to-infrastructure (V2I) communications, vehicle-to-network (V2N) communications, and vehicle-to-vehicle (V2V) communications, as well as communications between vehicles and other possible network entities or devices. V2X communications can also refer to communications between other non-vehicle devices participating in the V2X network to share V2X-related information.

[0043] V2X communications may, for example, follow the 3GPP Cellular V2X (C-V2X) specification, or follow one or more other or subsequent standards, whereby vehicles and other devices and network entities may communicate. V2X communications may utilize both long-range (e.g., cellular) communications and short- to medium-range (e.g., non-cellular) communications. V2X communications with cellular capabilities may be referred to as cellular V2X (C-V2X) communications. C-V2X systems may use various cellular radio access technologies (RATs), such as 4G LTE or 5G NRRAT. Certain LTE standards available in V2X systems may be referred to as LTE-Vehicle (LTE-V) standards.

[0044] As shown, the exemplary V2X system includes multiple user devices. As used herein in the context of a V2X system, "user device" may generally refer to a device associated with a mobile participant or traffic participant in the V2X system, i.e., a movable (mobile) communication device such as a vehicle and a pedestrian user equipment (PUE) device. The user devices in the exemplary V2X system include PUEs 104A and 104B and vehicles 106A and 106B.

[0045] The vehicle 106 may constitute various types of vehicles. For example, the vehicle 106A may be a road vehicle or automobile, a public transportation vehicle, or another type of vehicle. The vehicle 106 may perform wireless communications in various ways. For example, the vehicle 106A may include a communication device that is part of or housed in the vehicle, or may perform communications via wireless communication devices currently contained within or otherwise carried by the vehicle, such as user equipment (UE) devices (e.g., smartphones or similar devices) carried or worn by the driver, passengers, or other persons on the vehicle, among other possibilities. For simplicity, the term "vehicle," as used herein, may include wireless communication equipment that represents the vehicle and performs its communications. Thus, for example, when the vehicle 106A is referred to as performing wireless communications, it should be understood that, more specifically, certain wireless communication equipment associated with and carried by the vehicle 106A is performing the wireless communications.

[0046] Pedestrian UEs (PUEs) 104 may constitute various types of user equipment (UE) devices, i.e., portable devices capable of wireless communication, such as smartphones, smartwatches, etc., and may be associated with various types of users. Thus, PUEs 104 are UEs and may be referred to as UEs or UE devices. Note that while UEs 104 may be referred to as PUEs (pedestrian UEs), they may not necessarily be carried by people actively walking near roads or streets. PUEs may refer to UEs participating in a V2X system that are carried by a stationary person, by a person walking or running, or by a person in a vehicle that may not substantially support the power capabilities of the device, such as a bicycle, scooter, or certain motor vehicles. Note also that not necessarily all UEs participating in a V2X system are PUEs.

[0047] The user equipment is capable of communicating using multiple wireless communication standards. For example, in addition to at least one cellular communication protocol (e.g., GSM, UMTS, LTE, LTE-A, LTE-V, HSPA, 3GPP2 CDMA2000, 5G NR, etc.), the UE 104A can be configured to communicate using wireless networking (e.g., Wi-Fi) and / or peer-to-peer wireless communication protocols (e.g., Bluetooth, Wi-Fi peer-to-peer, etc.). If desired, the UE 104A can also or alternatively be configured to communicate using one or more global navigation satellite systems (GNSS, such as GPS or GLONASS), one or more mobile television broadcast standards (e.g., ATSC-M / H), and / or any other wireless communication protocols. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

[0048] In 3GPP Releases 12 to 15, sidelink transmission was designed based on the LTE-A air interface. However, the LTE-A air interface may not meet the service requirements specified by International Mobile Telecommunications 2020 (IMT-2020). To migrate to fifth-generation (5G) networks, 3GPP subsequently initiated the standardization process for NR sidelink transmission in Release 16 in June 2018. While the primary use case for Release 16 NR sidelink transmission also targets V2X, services are no longer limited to the Collaborative Awareness Messaging (CAM) and Distributed Environment Notification (DENM) used in V2X. Instead, the primary goal is to support next-generation driving use cases, including advanced driving, platooning, extended sensors, and remote driving. These use cases require low latency, high reliability, high throughput, and high connection density. To meet these new requirements, NR sidelink transmission introduces the following four new enhancements. Sidelink transmission now supports not only broadcast but also unicast and multicast. For unicast and multicast, a physical sidelink feedback channel (PSFCH) is newly introduced for the receiving UE to reply the decoding status to the transmitting UE. In addition, to improve latency performance, unauthorized transmission adopted in NR uplink transmission is also provided in NR sidelink transmission. In addition, to alleviate resource conflicts between different sidelink transmissions initiated by different UEs, enhanced channel sensing and resource selection procedures are added, which requires a new design of the physical sidelink control channel. Finally, in order to achieve high connection density and congestion control, QoS management features are supported in NR sidelink transmission. Although Release 16 sidelink transmission is focused only on V2X, 3GPP is planning further enhancements to extend the sidelink scenarios to interactive gaming, enhanced public safety, enhanced V2X, advanced relaying and other usage scenarios. Therefore, although explained in the context of V2X networking, the various implementations are not limited to any specific usage model or network.

[0049] As shown in the figure, some user devices may be able to communicate directly with each other, that is, without intermediate infrastructure equipment such as base station 102A or RSU 110A. As shown in the figure, vehicle 106A can directly perform V2X-related communications with vehicle 106B. Similarly, vehicle 106B can directly perform V2X-related communications with PUE 104B. Such peer-to-peer (P2P) communication can be referred to as "side link communication", and in the case of some LTE implementation schemes, a "side link" interface such as PC5 interface can be utilized. In some LTE implementation schemes, the PC5 interface supports direct cellular communication between user devices (e.g., between vehicles 106), while the Uu interface supports cellular communication with infrastructure equipment such as base stations. The LTE PC5 / Uu interface is used only as an example, and PC5 as used herein can represent various other possible wireless communication technologies that allow direct side link communication between user devices, while Uu can represent cellular communication performed between user devices and infrastructure equipment such as base stations. For example, at least according to some implementation schemes, NR V2X side link communication technology can also be used to perform device-to-device communication. It is also noted that some user equipment in a V2X system (such as, for example, the PUE 104A) may not be able to perform sidelink communications, for example, because they lack certain hardware required to perform such communications.

[0050] As shown, the exemplary V2X system includes multiple infrastructure devices in addition to the aforementioned user devices. As used herein, "infrastructure devices" in the context of a V2X system refer to certain devices in the V2X system that are not user devices and are not carried by traffic participants (i.e., pedestrians, vehicles, or other mobile users), but that facilitate user devices' participation in the V2X network. The infrastructure devices in the exemplary V2X system include a base station 102A and a roadside unit (RSU) 110A.

[0051] Base station (BS) 102A may be a base transceiver station (BTS) or a cell site ("cellular base station") and may include hardware capable of wirelessly communicating with user equipment (eg, with user equipment 104A and 106A).

[0052] The communication area (or coverage area) of a base station may be referred to as a "cell" or "coverage area". The base station 102A and user equipment such as PUE 104A may be configured to communicate over a transmission medium using any of a variety of radio access technologies (RATs), also known as wireless communication technologies or telecommunication standards, such as GSM, UMTS, LTE, Advanced LTE (LTE-A), LTE-Vehicle (LTE-V), HSPA, 3GPP2 CDMA2000, 5G NR, and the like. Note that if the base station 102A is implemented in the context of LTE, it may alternatively be referred to as an "eNodeB" or eNB. Note that if the base station 102A is implemented in the context of NR, it may alternatively be referred to as a "gNodeB" or gNB.

[0053] As shown, base station 102A may also be configured to communicate with network 100 (e.g., a V2X network, as well as a cellular service provider's core network, a telecommunications network such as a public switched telephone network (PSTN), and / or the Internet, among other possibilities). Thus, base station 102A may facilitate communications between user devices and / or between user devices and network 100. Cellular base station 102A may provide user devices such as UE 104A with various communication capabilities, such as voice, SMS, and / or data services. Specifically, base station 102A may provide connected user devices, such as UE 104A and vehicle 106A, with access to the V2X network.

[0054] Thus, while base station 102A may serve as a "serving cell" for user equipment 104A and 106A, Figure 1 102A. The user devices shown, i.e., user devices 104A, 104B, 106A, and 106B, may also be able to receive signals from (and may be within communication range of) one or more other cells (which may be provided by base stations 102B-N and / or any other base stations), such cells may be referred to as "neighboring cells." Such cells may also be able to facilitate communications between user devices and / or between user devices and network 100. Such cells may include "macro" cells, "micro" cells, "pico" cells, and / or cells of any other variety of granularity of service area size. For example, in Figure 1 The base stations 102A-102B shown in FIG may be macro cells, while the base station 102N may be a micro cell. Other configurations are also possible.

[0055] A roadside unit (RSU) 110A constitutes another infrastructure device that may be used to provide certain user devices with access to the V2X network. The RSU 110A may be one of various types of devices, such as a base station, e.g., a transceiver station (BTS) or a cell site ("cell base station"), or another type of device that includes hardware capable of wirelessly communicating with user devices and facilitating their participation in the V2X network.

[0056] The RSU 110A may be configured to communicate using one or more wireless networking communication protocols (e.g., Wi-Fi), cellular communication protocols (e.g., LTE, LTE-V, etc.), and / or other wireless communication protocols. In some embodiments, the RSU 110A may be capable of communicating with devices using a "sidelink" technology such as LTE PC5 or NR V2X sidelink communication technology.

[0057] The RSU 110A may communicate directly with user devices, such as vehicles 106A and 106B, as shown. The RSU 110A may also communicate with the base station 102A. In some cases, the RSU 110A may provide certain user devices (e.g., vehicle 106B) with access to the base station 102A. Although the RSU 110A is shown as communicating with the vehicle 106, it may also (or otherwise) be able to communicate with the PUE 104. Similarly, the RSU 110A may not necessarily forward user device communications to the base station 102A. In some embodiments, the RSU 110A may constitute the base station itself and / or may forward communications to the server 120.

[0058] As shown, server 120 constitutes a network entity of the V2X system and may be referred to as a cloud server. Base station 102A and / or RSU 110A may relay certain V2X-related communications between user devices 104 and 106 and server 120. Server 120 may be configured to process certain information collected from multiple user devices and may manage V2X communications to the user devices to coordinate traffic activities. In various other embodiments of the V2X system, various functions of cloud server 120 may be performed by infrastructure equipment such as base station 102A or RSU 110A, by one or more user devices, or / and not at all.

[0059] Figure 2

[0060] Figure 2 102 (e.g., Figure 1 A user equipment (UE) device 104 (e.g., a base station 102A in FIG. Figure 1UE 104 may be a device with cellular communication capabilities, such as a mobile phone, handheld device, computer or tablet computer, or virtually any type of portable wireless device.

[0061] The UE 104 may include a processor (processing element) configured to execute program instructions stored in a memory. The UE 104 may perform any of the method embodiments described herein by executing such stored instructions. Alternatively or in addition, the UE 104 may include a programmable hardware element, such as an FPGA (field programmable gate array), an integrated circuit, and / or any of various other possible hardware components configured to perform any of the method embodiments described herein or any portion of any of the method embodiments described herein.

[0062] UE 104 may include one or more antennas for communicating using one or more wireless communication protocols or technologies. In some embodiments, UE 104 may be configured to communicate using, for example, CDMA2000 (1xRTT / 1xEV-DO / HRPD / eHRPD) or LTE using a single shared radio and / or GSM or LTE using a single shared radio. The shared radio may be coupled to a single antenna, or may be coupled to multiple antennas (e.g., for MIMO) for performing wireless communications. Typically, the radio may include any combination of a baseband processor, analog radio frequency (RF) signal processing circuitry (e.g., including filters, mixers, oscillators, amplifiers, etc.), or digital processing circuitry (e.g., for digital modulation and other digital processing). Similarly, the radio may implement one or more receive chains and transmit chains using the aforementioned hardware. For example, UE 104 may share one or more portions of a receive chain and / or transmit chain between multiple wireless communication technologies such as those discussed above.

[0063] In some embodiments, the UE 104 may include a separate transmit chain and / or receive chain (e.g., including separate antennas and other radio components) for each wireless communication protocol with which it is configured to communicate. As another possibility, the UE 104 may include one or more radio components shared between multiple wireless communication protocols, and one or more radio components used uniquely by a single wireless communication protocol. For example, the UE 104 may include a shared radio component for communicating using either LTE or 5GNR (or, in various possibilities, either LTE or 1xRTT, or either LTE or GSM), and independent radio components for communicating using each of Wi-Fi and Bluetooth. Other configurations are also possible.

[0064] Figure 3 —UE block diagram

[0065] Figure 3 An exemplary block diagram of a UE 104 according to some embodiments is shown. As shown, the UE 104 may include a system on a chip (SOC) 300, which may include components for various purposes. For example, as shown, the SOC 300 may include a processor 302 that may execute program instructions for the UE 104, and a display circuit 304 that may perform graphics processing and provide display signals to a display 360. One or more processors 302 may also be coupled to a memory management unit (MMU) 340 (which may be configured to receive addresses from the one or more processors 302 and convert those addresses into locations in a memory (e.g., memory 306, read-only memory (ROM) 350, NAND flash memory 310)), and / or to other circuits or devices (such as the display circuit 304, wireless communication circuitry 330, connector I / F 320, and / or display 360). The MMU 340 may be configured to perform memory protection and page table translation or setup. In some embodiments, the MMU 340 may be included as part of the processor 302.

[0066] As shown, SOC 300 may be coupled to various other circuits of UE 104. For example, UE 104 may include various types of memory (e.g., including NAND flash memory 310), a connector interface 320 (e.g., for coupling to a computer system, a docking station, a charging station, etc.), a display 360, and wireless communication circuitry 330 (e.g., for LTE, LTE-A, LTE-V, 5GNR, CDMA2000, Bluetooth, Wi-Fi, GPS, etc.). The UE may also include at least one SIM device, and may include two SIM devices, each providing a respective International Mobile Subscriber Identity (IMSI) and associated functionality.

[0067] As shown, the UE device 104 may include at least one antenna (and, in various possibilities, multiple antennas, e.g., for MIMO and / or for implementing different wireless communication technologies) for performing wireless communications with base stations, access points, and / or other devices. For example, the UE device 104 may use antenna 335 to perform wireless communications.

[0068] The UE 104 may also include and / or be configured for use with one or more user interface elements. The user interface elements may include various elements such as a display 360 (which may be a touch screen display), a keyboard (which may be a separate keyboard or may be implemented as part of the touch screen display), a mouse, a microphone and / or speakers, one or more cameras, one or more buttons, and / or any of a variety of other elements capable of providing information to a user and / or receiving or interpreting user input.

[0069] As described herein, the UE 104 may include hardware components and software components for implementing features such as those described herein for performing V2X sidelink communications. The processor 302 of the UE device 104 may be configured to implement part or all of the methods described herein, for example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). In other embodiments, the processor 302 may be configured as a programmable hardware element such as an FPGA (field programmable gate array), or as an ASIC (application-specific integrated circuit). Alternatively (or in addition), in combination with one or more of the other components 300, 304, 306, 310, 320, 330, 335, 340, 350, 360, the processor 302 of the UE device 104 may be configured to implement part or all of the features described herein, such as the features described herein.

[0070] Figure 4 -Base station block diagram

[0071] Figure 4 A base station 102 (e.g., Figure 1 102A). Figure 4 The base station 102 is only one example of a possible base station. As shown, the base station 102 may include a processor 404 that may execute program instructions for the base station 102. The processor 404 may also be coupled to a memory management unit (MMU) 440 or other circuit or device that may be configured to receive addresses from the processor 404 and translate those addresses into locations in memory (e.g., memory 460 and read-only memory (ROM) 450).

[0072] The base station 102 may include at least one network port 470. The network port 470 may be configured to couple to a telephone network and provide access to the telephone network for a plurality of devices, such as the UE device 104.

[0073] The network port 470 (or an additional network port) may also or alternatively be configured to couple to a cellular network, such as a core network of a cellular service provider. The core network may provide mobility-related services and / or other services to multiple devices, such as the UE device 104. In some cases, the network port 470 may couple to a telephony network via the core network, and / or the core network may provide a telephony network (e.g., in other UE devices served by the cellular service provider).

[0074] Base station 102 may include at least one antenna 434 and possibly multiple antennas. The at least one antenna 434 may be configured to function as a wireless transceiver and may be further configured to communicate with UE device 104 via radio 430. Antenna 434 communicates with radio 430 via communication chain 432. Communication chain 432 may be a receive chain, a transmit chain, or both. Radio 430 may be configured to communicate via various wireless communication standards, including but not limited to LTE, LTE-A, LTE-V, GSM, UMTS, CDMA2000, 5G NR, Wi-Fi, and the like.

[0075] Base station 102 may be configured to communicate wirelessly using multiple wireless communication standards. In some cases, base station 102 may include multiple radios that may enable base station 102 to communicate according to multiple wireless communication technologies. For example, as one possibility, base station 102 may include an LTE radio for communicating according to LTE and a Wi-Fi radio for communicating according to Wi-Fi. In such a case, base station 102 may be capable of operating as both an LTE base station and a Wi-Fi access point. As another possibility, base station 102 may include a multimode radio capable of communicating according to any of multiple wireless communication technologies (e.g., LTE and NR, LTE and Wi-Fi, LTE and UMTS, LTE and CDMA2000, UMTS and GSM, etc.).

[0076] As further described later herein, BS 102 may include hardware and software components for implementing or supporting a specific implementation of the features described herein. The processor 404 of the base station 102 may be configured to implement or support a specific implementation of part or all of the methods described herein, for example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively, the processor 404 may be configured as a programmable hardware element such as an FPGA (field programmable gate array), or as an ASIC (application-specific integrated circuit), or a combination thereof. Alternatively (or in addition), in combination with one or more of the other components 430, 432, 434, 440, 450, 460, and 470, the processor 404 of the base station 102 may be configured to implement or support a specific implementation of part or all of the features described herein.

[0077] V2X side link communication

[0078] According to various implementations, sidelink communication refers to a special type of communication mechanism between devices that is not carried through a base station, such as an eNB / gNB. In other words, the devices communicate with each other without going through the base station. In one sense, the devices can be said to communicate directly with each other, i.e., using D2D or peer-to-peer (P2P) communication. However, as previously mentioned, adapting this type of communication may require a new physical layer design.

[0079] Many recent studies have identified technical solutions that require sidelink designs, such as those in 5G-NR, to meet the requirements of advanced V2X services, including support for sidelink unicast, sidelink multicast, and sidelink broadcast. Many specific use cases for advanced V2X services have been identified, such as vehicle platooning, extended sensors, advanced driving, and remote driving.

[0080] In LTE V2X, broadcast sidelink communications are supported, where sidelink connection maintenance is performed by using keep-alive messages transmitted between upper layers (e.g., application layer, non-access stratum, etc.) of wireless devices in the communication. For example, in addition to broadcast sidelink communications, NR V2X also supports unicast and multicast sidelink communications.

[0081] To support such V2X or D2D sidelink communications, various communication channels (e.g., control channels, data channels) may need to be provided. Therefore, this document proposes various possible techniques for supporting V2X sidelink communications, including various possible V2X channel design features and considerations. Various embodiments herein propose a new physical sidelink feedback channel (PSFCH) format and modifications to support range extension of sidelink transmissions in NR. For the purposes of discussing embodiments of the present invention, some basic considerations for NR formats for V2X include the following:

[0082] In NR Release 16, the logical, transport, and physical layer parameters for sidelink transmissions are defined. The physical layer includes the physical sidelink (SL) control channel (PSCCH), the physical SL shared channel (PSSCH), and the physical SL feedback channel (PSFCH). The physical SL control channel (PSCCH) is equivalent to the downlink control channel (PDCCH) in cellular traffic on the Uu interface. It contains part of the sidelink control information (SCI) and provides the information required by the receiving UE to be able to receive and demodulate the PSSCH.

[0083] PSSCH: PSSCH is transmitted by a sidelink transmission UE and carries sidelink transmission data, a system information block (SIB) for radio resource control (RRC) configuration, and a portion of sidelink control information (SCI).

[0084] PSFCH: The PSFCH is transmitted by sidelink receiving UEs for unicast and multicast. The PSFCH carries 1 bit of information on 1-RB for HARQ acknowledgement (ACK) and negative ACK (NACK). In addition, channel state information (CSI) is carried in the medium access control (MAC) control element (CE) on the PSSCH instead of the PSFCH.

[0085] PSCCH: When traffic destined for a receiving UE arrives at a transmitting UE, the transmitting UE should first send the PSCCH, which carries a portion of the SCI that can be decoded by any UE for channel sensing purposes, including the time-frequency resources reserved for transmission, demodulation reference signal (DMRS) pattern, antenna port, etc. For the PSCCH, quadrature phase shift keying (QPSK) is used to transmit the SCI.

[0086] Central-to-sidelink transmission and reception utilizes the concept of a resource pool (RP). A resource pool is a set of resources allocated for sidelink operations. A resource pool may include subframes and the physical resource blocks (PRBs) within them. There are two resource allocation methods: In Mode 1, the eNB indicates the resources to be used for transmission, including those within the RP. In Mode 2, the UE selects the RP and its resources from a set of allocated pools.

[0087] Sidelink Control Information (SCI) payload / split into 2 parts (or stages)

[0088] SCI Stage 1

[0089] The Phase 1 SCI includes in its payload: priority; PSSCH frequency resource allocation; PSSCH time resource allocation; resource reservation period; DMRS pattern; SCI Phase 2 format; beta_offset indicator; number of DMRS ports; modulation and coding scheme (MCS); MCS table index; PSFCH overhead indication; and reserved bits. In some embodiments, each resource pool may allow a single SCI Phase 1 format. Phase 1 SCI may be carried in the Physical Sidelink Control Channel (PSCCH).

[0090] SCI Stage 2

[0091] Phase 2 SCI has two formats, including: format A for unicast and multicast HARQ option 2, broadcast and its payload includes HARQ process number; new data indicator; redundancy version; source ID; destination ID; HARQ feedback enable / disable indicator; / Cast type indicator; and CSI request; and format B for multicast HARQ option 1, and its payload may include: HARQ process number; new data indicator; redundancy version; source ID; destination ID HARQ feedback enable / disable indicator / r; area ID; and communication range requirement. SCI Phase 2 is carried in the physical / sidelink shared channel (PSSCH)

[0092] PSFCH format

[0093] The PSFCH format can be a sequence-based short format. The PSFCH format can have the same sequence as the Physical Uplink Control Channel (PUCCH) format 0. In the time domain, the resources include the repetition of the PSFCH format to two consecutive symbols. The first symbol can be used for AGC training, and the other symbol is used for the gap (i.e., Tx / Rx switching) immediately after the PSFCH transmission. In the frequency domain, the short format is a single PRB, i.e., the entire subchannel is not used.

[0094] PSFCH Resources

[0095] Each PSFCH can be mapped to time, frequency, and code resources. In the time domain, the slot offset from its corresponding PSSCH is 2 or 3, and the resource pool can be preconfigured. In the frequency domain, the resource is determined by the corresponding PSSCH starting subchannel index and slot index. Code domain resources are explored for multicast HARQ feedback option 2.

[0096] Embodiments of the present invention may also extend the physical sideband feedback channel (PSFCH) format to extend coverage in narrowband device-to-device wireless communication networks, such as Off-Grid Radio Systems (OGRS) and 3GPP Narrowband Internet of Things (NB-IoT) networking systems. Narrowband Internet of Things (NB-IoT) is a low-power wide-area network (LPWAN) radio technology standard developed by 3GPP to enable a wide range of cellular devices and services. The specification was frozen in 3GPP Release 13 (LTE Advanced Pro) in June 2016. NB-IoT focuses specifically on indoor coverage, low cost, long battery life, and high connection density. NB-IoT uses a subset of the LTE standard but limits the bandwidth to a single narrow frequency band of 200kHz. It uses OFDM modulation for downlink communications and SC-FDMA for uplink communications.

[0097] Off-Grid Radio System (OGRS) Considerations :

[0098] 3GPP's OGRS alternative design may need to consider a maximum coupling loss (MCL) > 160dB, and based on the 3GPP model in TS37.885, the path loss can be higher than 140dB at 2km at 900MHz. In NR, the UE design can be targeted for a link budget of 140dBi. However, due to at least the gNodeB (gNB) / UE receive antenna difference, a coverage loss of greater than 20dB should be considered. With an antenna gain difference of 12 / 21dB, the gNB antenna gain factor is approximately 8 / 17dB, while the UE antenna gain is -4dBi. With a 4dB noise figure loss difference, the gNB noise figure is approximately 5dB, and the UE noise figure is approximately 9dB.

[0099] For 3GPP LTE, narrowband Internet of Things (NB-IoT) solutions can be considered to enhance NR sidelink coverage. For example, LTE NB-IoT can support 160dB MCL with 20dB coverage extension and support 3.75kHz SCS, increase repetition and periodicity in the primary synchronization signal (PSS), secondary synchronization signal (SSS) and primary broadcast channel (PBCH). Control and data signals can be repeated in the time domain, which promotes narrowband physical downlink control channel (NPDCCH) with up to 2048 repetitions and narrowband physical uplink shared channel (NPUSCH) format 1 (UL-SCH) with up to 128 repetitions. In addition, resource units (RUs) can be defined with longer durations of up to 32ms and NPUSCH format 2 UCI with up to 128 repetitions.

[0100] With the foregoing considerations in mind, embodiments are directed to enhancing the NR V2X PSFCH to extend coverage and thereby facilitate sideband feedback to meet the needs of various network environments and protocols that utilize sideband transmission. Accordingly, various embodiments define new PSFCH formats, including resource configuration and mechanisms for determining their use, and signaling formats for utilizing the new PSFCH formats of embodiments of the present invention. As described herein, embodiments are directed to long PSFCH formats and short PSFCH formats, where the short format refers to existing format 0 designs, such as those previously discussed, and the long PSFCH format 1 of embodiments of the present invention, to facilitate extending sideband feedback in NR to various 3GPP V2X, D2D and / or narrowband network specifications and conditions. The proposed invention embodiments are directed to an extended PSFCH format, referred to herein as "PSFCH format 1" or "long PSFCH format"

[0101] According to certain aspects of embodiments of the present invention, acknowledgment and / or negative acknowledgment (ACK / NACK) messages sent on the PSFCH may now have the traditional "short PSFCH format" or "PSFCH format 0" or "long PSFCH format" or "PSFCH format 1" to provide the required ACK / NACK feedback and adjust networking parameters accordingly. In some embodiments, a sequence-based short PSFCH format may be used for sidelink ACK / NACK messaging, where no more than one or two symbols are used for ACK / NACK messages. Alternatively, a long PSFCH format as described in various embodiments may now be used, where more than two symbols are used for ACK / NACK messages, up to the size of an entire slot (e.g., up to 14 symbols for a 14-symbol slot structure). In either the long or short PSFCH format, the ACK / NACK message may be repeated for each symbol to increase the likelihood of successful reception by the receiving device.

[0102] Figure 5 and Figure 6

[0103] refer to Figure 5 and Figure 6 , shows an exemplary resource configuration of PSFCH format 1 (or long PSFCH format). Figure 5In a first example, a long PSFCH resource configuration 500 is shown, in which the physical uplink control channel PUCCH format 1 is used as the new PSFCH format 1. In an exemplary embodiment, the frequency resources of the PSFCH format 1 can be the remaining physical resource blocks (PRBs) 510 of the resource pool 500 that are not used in Release 16 NR V2X. For example, the resource pool 500 is configured with 65-PRBs 510, and its subchannel 520 size is 10 PRBs 510. The remaining 5-PRBs are not used for sidelink transmission, and therefore these remaining PRBs 510 can be used as frequency resources for PSFCH ACK / NACK transmission.

[0104] Additionally, or alternatively, in certain embodiments, frequency resources for PSFCH format 1 may be simply allocated as the last several subchannels 520 of the resource pool 500 .

[0105] refer to Figure 6 In other exemplary embodiments, frequency resources for PSFCH format 1 may be at upper PRBs 612 and lower PRBs 614 of resource pool 600. Furthermore, if desired, PSFCH format 1 resources may be allocated in the middle of resource pool 600 (not shown) for frequency diversity gain.

[0106] In some embodiments, sidelink control information (SCI) can be transmitted on a physical sidelink control channel (PSCCH) 630, and a data payload can be transmitted on a physical sidelink shared channel (PSSCH) 635. As an example, sidelink control information (SCI) can specify resources to be used for an upcoming PSFCH ACK / NACK message associated with the data payload. In some embodiments, SCI can specify specific time, frequency, and / or code resources. Typically, the PSFCH resource can be offset by 2 or 3 slots from the corresponding PSSCH (i.e., the PSFCH can be scheduled to occur 2 or 3 slots after the PSSCH), but embodiments of the present invention are not limited in this manner.

[0107] Figure 7 and Figure 8

[0108] refer to Figure 7 and Figure 8 , shows an additional implementation scheme of resource configuration of PSFCH resources in special cases, and will now be described. Figure 7An exemplary embodiment is shown in which frequency pool resources 700 are configured exclusively using PSFCH format 1 (long format) resources. The PRBs 710 configured in this embodiment use designated resources of PSFCH format 1 exclusively for ACK / NACK messages. For example, in time resources, the repetition of PSFCH format 1 over two consecutive symbols in a time slot enables a configuration in which the first symbol can be used for automatic gain control (AGC) training and one symbol is used for a GAP (i.e., Tx / Rx switching) immediately following the PSFCH transmission of the ACK / NACK message.

[0109] In the configuration of frequency resources, only a single physical resource block (PRB) 714 may be used instead of the entire subchannel 730. If the PSFCH format 0 periodicity is not equal to zero, then PSFCH format 1 resources may be configured.

[0110] Figure 8

[0111] Figure 8 An exemplary embodiment is shown where both PSFCH format 0 and format 1 resources may be jointly allocated simultaneously in the same resource pool 800 .

[0112] In this embodiment, PSFCH format 1 resources are configured independently of PSFCH format 0 resource configurations. As can be seen, PRBs 814 can be used to configure PSFCH format 1 resources for determining long PSFCH formats required for ACK / NACK messaging as discussed with respect to previous embodiments, and for those using sideband transmissions that conform to conventional PSFCH subslot timing, short PSFCH formats can be configured using subslots 824 within PSCCH and PSSCH subchannels 830. In this way, flexible, adaptive resource configuration can be used to enhance PSFCH.

[0113] Figure 9

[0114] Go to Figure 9 , depicts an exemplary embodiment of a long PSFCH format or PSFCH format 1 content 900. PSFCH format 1 may include one or two bits of information 905, 910 regarding a hybrid automatic repeat request (HARQ) acknowledgement (ACK). In this exemplary embodiment, the long PSFCH format may utilize only one slot in the time domain and one resource block (RB) in the frequency domain. Except for AGC symbols 915 and GAP symbols 920, the entire slot may be used for PSFCH transmission, and an OCC of up to six slot lengths may be applied. In some embodiments, intra-slot frequency hopping is supported for PSFCH format 1.

[0115] Long PSFCH format resource determination

[0116] Now refer to Figure 10 The resource pool 1000 depicts the resource mapping between the PSSCH 1030 and PSFCH format 1 1014. In some embodiments, the number of subchannels is equal to the number of PSFCHs in a time slot, and there is a one-to-one mapping in the frequency domain. For example, if the PSSCH uses the i-th subchannel, the i-th PSFCH can be used for HARQ feedback. In some embodiments, a time gap is maintained between the PSSCH 1030 and PSFCH format 1 1014. Such a time gap can be (pre-)configured per resource pool or can be predefined. This time gap can be indicated in the SCI associated with the PSSCH.

[0117] One-to-one mapping can be applied to unicast or multicast HARQ Option 1. For multicast HARQ Option 2, more resources may be required. In various embodiments, a code field (OCC) can be applied to support multiple PSFCHs, and more than one PSFCH time / frequency resource can be associated with one PSSCH resource. In alternative embodiments, the number of subchannels does not need to be equal to the number of PSFCHs in a time slot.

[0118] Figure 11 : Indexing PSFCH resources

[0119] refer to Figure 11 The two options for indexing PSFCH resources include frequency first and time second, where the PSFCH resource index 1110 depends on the slot number. For example, the PSFCH resource in the i-th slot number is indexed with [(i-1)*N, i*N-1], where N is the number of PSFCH resources per slot.

[0120] For a PSSCH transmission in time slot j, the corresponding PSFCH resource index is greater than (j+k-1)*N, where k is the configured minimum slot offset between PSSCH and PSFCH. Figure 11 Also shown is a PSFCH resource index 1150, where the PSFCH is indexed by time first and frequency second. In other embodiments, the PSFCH may be indexed by frequency first, time second, and code third (not shown).

[0121] Signaling of short and long PSFCH formats

[0122] Both short PSFCH format resources and long PSFCH format resources are configured. The use of short PSFCH format resources or long PSFCH format resources may depend on several factors. For example, in a multicast session configuration and communication range requirements (multicast HARQ option 1), if the communication range requirement is greater than a threshold, the long PSFCH format may be used with the configured long PSFCH resources, and if the communication range requirement is less than a threshold, the short PSFCH format may be used with the configured short PSFCH resources. In various embodiments, the threshold may be configured (in advance) per resource pool or per data priority per resource pool. For example, in a unicast PC5-RRC configuration, the data priority may provide an indication. If the data priority is above the threshold, the long PSFCH format may be used with the configured long PSFCH resources, and if the data priority is below the threshold, the short PSFCH format may be used with the configured short PSFCH resources. Similarly, the threshold may be configured (in advance) per resource pool or per data priority per resource pool.

[0123] In some embodiments, the use of short PSFCH format resources or long PSFCH format resources may depend on the SL-RSRP measurement at the RxUE. For example, if the measured SL-RSRP is above a threshold, the short PSFCH format may be used, while if the measured SL-RSRP is below a threshold, the long PSFCH format may be used. The SL-RSRP threshold may be (pre-)configured per resource pool, per resource pool per data priority, or based on a MAC CE indication.

[0124] In the L3 filtered sidelink RSRP reporting from the Rx UE to the Tx UE for open-loop power control, if the reported sidelink RSRP is greater than the threshold, the Tx UE can decide / indicate the short PSFCH format. On the other hand, if the reported sidelink RSRP is less than the threshold, the Tx UE can decide / indicate the long PSFCH format.

[0125] Sidelink CSI feedback from the Rx UE to the Tx UE for adaptive modulation and coding (AMC) can be an indicator. For example, if the reported CQI is below one level, the Tx UE can decide / indicate the long PSFCH format, and if the reported CQI is above one level, the Tx UE can decide / indicate the short PSFCH format.

[0126] In other embodiments, the use of short PSFCH format resources or long PSFCH format resources may depend on the SCI indication. For example, SCI level 2 may indicate whether to use the long PSFCH format or the short PSFCH format.

[0127] For SCI format 2-A or SCI format 2-B, an explicit field can be used to indicate whether the long PSFCH format or the short PSFCH format can be used. For example, SCI format 2-A reuses the "Cast Type Indicator" field to indicate the long or short PSFCH format. In addition, SCI format 2-B can reuse the "Communication Range Requirement" field to indicate the long or short PSFCH format.

[0128] In one embodiment, the position information in the sidelink unicast can be applied to make the determination. SCI format 2-B can be applied to unicast or multicast HARQ feedback option 1. For unicast, the location of the Tx UE (e.g., zone ID) is transmitted. The "communication range requirement" may or may not be valid for sidelink unicast. The Rx UE calculates the Tx-Rx distance based on its own location. If the distance is greater than the threshold, the long PSFCH format is used. Otherwise, the short PSFCH format is used. If the Rx UE does not have its own location, the long or short PSFCH format can be determined based on the data priority. The use of short PSFCH format resources or long PSFCH format resources may depend on the application location information in the sidelink unicast.

[0129] A new SCI format (e.g., SCI format 2-C) can be applied to support the long PSFCH format. In one embodiment, the PSFCH format is determined based on the SCI format. If the Rx UE receives this SCI format, it automatically uses the long PSFCH format. If the Rx UE receives a legacy SCI format (e.g., SCI format 2-A or 2-B), it automatically uses the short PSFCH format.

[0130] In another embodiment, the distance-based determination may determine the PSFCH format based on location information included in the SCI format.More accurate geographical location information (in addition to the region ID) may also be used.

[0131] While the payload may exceed 12 bits, the "communication range requirement" may not be included in the new SCI format. Therefore, the receiving UE can calculate the Tx-Rx distance based on its own location. If this distance is greater than a threshold, the long PSFCH format can be used. Otherwise, the short PSFCH format can be used.

[0132] In one embodiment, if the Rx UE does not have its own location, it can determine the long or short PSFCH format based on data priority.Any one or a combination of these examples can be set to determine which PSFCH format to use.

[0133] Mode 2 spectrum sensing

[0134] NR SL Release 16 supports two operation modes for V2X packet transmission: 1) NR Mode-1, in which the gNB schedules SL resources, requiring the UE to obtain scheduling decisions from the gNB whenever the UE initiates V2X communication on the SL within the network coverage; and 2) NR Mode-2, in which the V2X UE autonomously performs resource selection from the configured resource pool. The concept of geographical areas can be used to measure the resource pool in an effort to avoid collisions in V2X message transmissions, which enables V2X UEs to communicate inside / outside the network coverage.

[0135] In the NR SL design, the physical sidelink control channel (PSCCH), which carries sidelink control information (SCI), can be time-division multiplexed with the associated physical sidelink shared channel (PSSCH). NR V2X can split the contents of the SCI payload into two parts, with the first part of the SCI carrying information related to the V2X UE's sensing operations. As part of reducing decoding complexity during sensing operations, the first SCI payload, broadcast to surrounding UEs, can carry information related to data QoS priority, occupied resource blocks, resource reservation intervals, and more. The second SCI transmission can carry information related to data decoding on the physical sidelink shared channel (PSSCH). The physical sidelink feedback channel (PSFCH) format 0 or short format can be designed to carry SL-HARQ feedback for the last one or two OFDM symbols of an occupied timeslot. The gNB can configure the resource pool with the flexibility to configure resources with or without PSFCH. The sidelink MAC control element (MAC-CE), designed to carry aperiodic SL channel state information reports from the RX UE to the TX UE, contains information related to channel quality information and rank indicators used for link adaptation, enabling transmission of more than one layer. For NR Mode 1, the gNB transmits downlink control information (DCI) carrying information related to the SL HARQ feedback report to the gNB, requesting retransmission resources for the transport block (TB). The DCI contains the feedback timing and the corresponding uplink resources required by the TX UE for the feedback report.

[0136] Figure 12 Sensing-based determination of HARQ format

[0137] refer to Figure 12, a method 1200 for determining whether to use a short format or a long format for the PSFCH is described. Here, the determination of whether to use PSFCH format 0 or format 1 for feedback in sideband transmissions is typically performed based on an evaluation of frequency resources received from other gNBs or UEs. For example, a UE may receive 1202 a resource pool configuration in a sideband control channel or PSCCH from a received signal upon decoding. That is, a receiving UE may monitor 1204 the received signal to determine which type of feedback format to use based on the physical characteristics of the actual received signal, QoS priority, occupied resource blocks, or an indicator in the received signal, as described above.

[0138] Therefore, in various embodiments, there are two levels of sideband control information (SCI) related to the determination of which PSFCH feedback format to use. The first part of the SCI carries information related to the sensing operation 1200 of the V2X UE in its payload. The first level SCI is broadcast to surrounding UEs as part of the PSCCH and can carry information related to the QoS priority of the data, occupied resource blocks, resource reservation intervals, etc. as part of reducing decoding complexity during the sensing operation 1200.

[0139] As described above, the UE can use many types of indications to determine whether to use PSFCH format 0 or format 1 feedback. For example, SCI information in the payload of the control channel can be used for this purpose, and the UE can set 1204 to monitor only the frequency region with PSCCH / PSSCH frequency resources in the received signal to sense when determining which sideband feedback format and what resources in the resource pool to utilize. Thus, in one embodiment, at 1206, the UE can perform sensing only on the PSCCH / PSSCH frequency resources of the received signal, and thus, the UE does not look at the long PSFCH resources or other signal components when sensing which feedback format to use, only the PSCCH and PSSCH resources.

[0140] In various embodiments, some of the elements of the methods shown may be performed concurrently, in an order different from that shown, may be substituted by other method elements, or may be omitted.

[0141] In the following, additional exemplary embodiments are provided.

[0142] One set of embodiments may include an apparatus comprising: a processor configured to cause a first wireless device to configure resources for the physical sidelink feedback channel (PSFCH). Furthermore, as with the previously described examples, determining whether to use PSFCH format 0 or PSFCH format 1 and / or how to signal which format to use may also or alternatively be performed by the processor configured to cause the first wireless device to perform these tasks, alone or in combination.

[0143] Yet another example embodiment may include a method comprising performing, by a wireless device, any or all of the foregoing examples.

[0144] Another example embodiment may include a device comprising: an antenna; a radio coupled to the antenna; and a processor operatively coupled to the radio, wherein the device is configured to perform or implement any or all of the foregoing examples.

[0145] Another exemplary set of embodiments may include a non-transitory computer-accessible memory medium including program instructions that, when executed at a device, cause the device to implement any or all portions of any of the foregoing examples.

[0146] Another exemplary set of embodiments may include a computer program comprising instructions for performing any or all portions of any of the foregoing examples.

[0147] Another exemplary set of embodiments may include an apparatus comprising means for performing any or all of the elements of any of the preceding examples.

[0148] Another exemplary set of embodiments may include an apparatus comprising a processor configured to cause a wireless device to perform any or all elements of any of the preceding examples.

[0149] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly stated to users.

[0150] The embodiments of the present disclosure may be implemented in any of a variety of forms. For example, some embodiments may be implemented as computer-implemented methods, computer-readable storage media, or computer systems. Other embodiments may be implemented using one or more custom-designed hardware devices such as ASICs. Other embodiments may be implemented using one or more programmable hardware elements such as FPGAs.

[0151] In some embodiments, a non-transitory computer-readable storage medium may be configured such that it stores program instructions and / or data, wherein the program instructions, if executed by a computer system, cause the computer system to perform a method, such as any one of the method embodiments described herein, or any combination of the method embodiments described herein, or any subset of any method embodiments described herein, or any combination of such subsets.

[0152] In some embodiments, a device (e.g., UE 104) may be configured to include a processor (or a group of processors) and a memory medium, wherein the memory medium stores program instructions, wherein the processor is configured to read and execute the program instructions from the memory medium, wherein the program instructions are executable to implement any of the various method embodiments described herein (or any combination of the method embodiments described herein, or any subset of any of the method embodiments described herein, or any combination of such subsets). The device may be implemented in any of various forms.

[0153] Although the above embodiments have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to encompass all such variations and modifications.

Claims

1. A processor comprising circuitry configured to cause a first wireless device to: Configuring radio resources for a physical sidelink feedback channel (PSFCH) to transmit an acknowledgment ACK or non-acknowledgment NACK message on the sidelink feedback channel using a long PSFCH format resource configuration, including allocating frequency resources for the long PSFCH format from remaining unused physical resource blocks (PRBs) in a resource pool for sidelink transmission of a physical sidelink control channel (PSCCH) and a physical sidelink shared channel (PSSCH), the PRBs remaining unused in PSCCH or PSSCH transmission because the number of PRBs in the resource pool cannot be divided evenly by a subchannel size of the resource pool.

2. The processor of claim 1 , wherein the processor is further configured to cause the first wireless device to: The resource mapping between the PSSCH and the long PSFCH format configuration is determined by: When the number of subchannels of the PSSCH is equal to the number of PSFCHs in a time slot, a one-to-one mapping is used in the frequency domain such that when the PSSCH uses the i-th subchannel, then the i-th PSFCH is used for hybrid automatic repeat request (HARQ) feedback; and When the number of subchannels of the PSSCH is not equal to the number of PSFCHs in the time slot, the PSFCH resources are indexed by one of frequency first time second indexing, time first frequency second indexing, or frequency first time second and code third indexing.

3. The processor of claim 1 , wherein the long PSFCH format is referred to as PSFCH format 1 and includes 1 or 2 bits of information about HARQ ACK, and wherein the PSFCH format 1 fits into a single slot of a radio frame in the time domain and is one PRB in the frequency domain. The processor of claim 3 , wherein intra-slot frequency hopping of PSFCH format 1 is supported.

5. The processor of claim 1 , wherein the processor is further configured to cause the first wireless device to: Before configuring radio resources, determining that the long PSFCH format resources should be used based on information included in a sidelink control information (SCI) payload of the physical sidelink control channel (PSCCH), wherein the resource pool is configured to include a number of PRBs in the physical sidelink feedback channel (PSFCH) equal to the number of subchannels in the physical sidelink shared channel (PSSCH), and wherein the resource pool includes a fixed time gap between each subchannel of the PSSCH and a corresponding PSFCH PRB.

6. The processor of claim 1 , wherein the processor is further configured to cause the first wireless device to: Before configuring radio resources, the long PSFCH format should be used according to at least one of the following: Multicast session configuration; Communication range requirements; Unicast PC5 - Radio Resource Control (RRC) configuration; Data prioritization; Sidelink reference signal received power (SL-RSRP) measurement at the wireless device; Layer 3 (L3) filtered sidelink RSRP reports received by the wireless device; sidelink channel quality indicator (CQI) feedback received by the wireless device; or An indicator is present in a sidelink control information payload of the physical sidelink control channel from the resource pool.

7. The processor of claim 6, wherein the processor is further configured to cause the first wireless device to: Before configuring radio resources, a signal is received to identify, based on sidelink control information in the physical sidelink control channel (PSCCH), that the long PSFCH format should be used and how to configure the long PSFCH format in the resource pool.

8. A wireless communication device comprising: at least one antenna, configured to radiate or receive electromagnetic signals of the wireless communication network; a radio coupled to the at least one antenna; and a processor coupled to the radio; wherein the processor is configured to cause the wireless communication device to: Radio resources are configured for a physical sidelink feedback channel PSFCH to transmit a hybrid automatic repeat request HARQ message using a long PSFCH format, wherein the radio resources are configured from remaining unused physical resource blocks (PRBs) of a resource pool used for sidelink transmission of a physical sidelink control channel (PSCCH) and a physical sidelink shared channel (PSSCH), the PRBs remaining unused in PSCCH or PSSCH transmission because the number of PRBs in the resource pool cannot be divided evenly by a subchannel size of the resource pool.

9. The wireless communication device of claim 8, wherein the processor is further configured to cause the wireless communication device to determine resource mapping between the PSSCH and the long PSFCH format configuration by: When the number of subchannels of the PSSCH is equal to the number of PSFCHs in a time slot, a one-to-one mapping is used in the frequency domain such that when the PSSCH uses the i-th subchannel, then the i-th PSFCH is used for hybrid automatic repeat request (HARQ) feedback; and When the number of subchannels of the PSSCH is not equal to the number of PSFCHs in the time slot, the PSFCH resources are indexed by one of frequency first time second indexing, time first frequency second indexing, or frequency first time second and code third indexing.

10. The wireless communication device of claim 8, wherein the long PSFCH format is referred to as PSFCH format 1 and includes 1 or 2 bits of information about HARQ ACK, and wherein the PSFCH format 1 fits into a single slot of a radio frame in the time domain and is one PRB in the frequency domain. The wireless communication device according to claim 10 , wherein intra-slot frequency hopping of PSFCH format 1 is supported.

12. The wireless communication device of claim 9, wherein the processor is further configured to cause the wireless communication device to: determining that a first acknowledgement message is to be transmitted according to a short PSFCH format referred to as PSFCH format 0; determining that a second acknowledgement message will be transmitted according to the long PSFCH format referred to as PSFCH format 1; and If the PSFCH format 0 periodicity is not equal to 0, the PSFCH format 1 resources can be exclusively configured for sidelink transmission relative to the PSFCH format 0 resources.

13. The wireless communication device of claim 8, wherein the processor is further configured to cause the wireless communication device to: PSFCH format 1 resources and PSFCH format 0 resources are jointly allocated in the same resource pool used for sidelink transmission of the physical sidelink control channel (PSCCH) and the physical sidelink shared channel (PSSCH).

14. The wireless communication device of claim 13, wherein the resources allocated with PSFCH format 1 comprise a plurality of PRBs of the resource pool, and wherein the resources allocated with PSFCH format 0 comprise a plurality of subslots in a subchannel of the resource pool.

15. A method for communicating in a wireless network using sidelink transmission with sidelink feedback forward error correction (FEC), the method comprising: Determining to use a long physical sidelink feedback channel (PSFCH) format, PSFCH format 1, wherein the PSFCH format 1 specifies radio resources to provide an ACK or NACK feedback indication to a transmitting device using sideband transmission based on predetermined criteria; Radio resources are configured for the PSFCH format 1 physical sidelink feedback channel PSFCH by allocating frequency resources for the PSFCH format 1 from the remaining unused physical resource blocks PRBs of the resource pool used for sidelink transmission of the physical sidelink control channel PSCCH and the physical sidelink shared channel PSSCH, the PRBs remaining unused in PSCCH or PSSCH transmission because the number of PRBs in the resource pool cannot be divided evenly by the subchannel size of the resource pool.

16. The method of claim 15, wherein the PSFCH format 1 includes information sized to fit within a radio frame slot and comprises: Automatic gain control, repeatable 1-bit or 2-bit information about hybrid automatic repeat request (HARQ) acknowledgement (ACK), and GAP, and wherein the PSFCH format 1 is suitable for one PRB in the frequency domain.

17. The method of claim 15, wherein if PSFCH format 0 periodicity is not equal to 0, PSFCH format 1 resources are exclusively configured relative to PSFCH format 0 resources; or PSFCH format 1 resources are configured independently of PSFCH format 0 resource configuration.

18. The method according to claim 16, further comprising: Resource mapping for HARQ feedback in the PSFCH format 1 resource configuration between the physical sidelink shared channel (PSSCH) present in multiple subchannels of the pre-configured resource pool; as well as When the number of PSSCH subchannels is equal to the number of PSFCHs in a slot, a one-to-one mapping of the PSFCHs is performed in the frequency domain, where there is a time gap between the corresponding HARQ feedback slots and PSSCH subchannels.

19. The method according to claim 18, wherein the time slot is pre-configured per resource pool, and PSFCH format 1 resources can be configured exclusively with respect to PSFCH format 0 resources.

20. The method of claim 17, wherein the number of subchannels of the PSSCH is not equal to the number of PSFCH feedbacks per time slot, and wherein in the mapping, the resources include indexing the PSFCH resources by time slot, wherein the i-th time slot number is indexed by [(i-1)*N, i*N-1], where N is the number of PSFCH resources per time slot.

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