User plane protocol design for new radio (NR) sidelink discovery message

Abstract

Aspects of the disclosure relate to discovery in wireless communication networks. According to one aspect, a user equipment (UE) can determine to use a service associated with sidelink communication, determine content of a discovery message including an indication that the message is a discovery message for the service, and determine a sidelink resource for transmitting the discovery message. The UE can then transmit, using the determined sidelink resource, the discovery message including the indication that the message is a discovery message for the service over a user plane. Other aspects, embodiments, and features are also claimed and described.

Description

Technical Field

[0001] The technology discussed below relates generally to wireless communication systems, and more particularly to user plane protocol design for New Radio (NR) bypass discovery messages. Background Art

[0002] Various network configurations can facilitate wireless communication between devices. In one configuration, a cellular network can enable user equipment (UE) to communicate with each other through signaling with nearby base stations or cells. Another wireless communication network configuration is a device-to-device (D2D) network, in which UEs can send signals directly to each other instead of going through an intermediate base station or cell. For example, a D2D communication network can utilize bypass signaling to facilitate direct communication between UEs. In some bypass network configurations, UEs can also communicate in a cellular network, typically under the control of a base station. Thus, UEs can be configured for uplink and downlink signaling via a base station, and also configured for bypass signaling directly between UEs without transmitting through a base station.

[0003] The ability to conduct direct, one-to-one communications between user equipment (UEs) using bypass continues to be enabled by new models of UE and continues to be implemented in public and private infrastructure. For example, bypass is used to enable vehicle-to-everything (V2X) communications. In some network configurations, a first UE may be outside the air interface coverage area of ​​a base station, but may be in close proximity to a second UE that is within the air interface coverage area of ​​the base station and has a connection to the base station. In such a case, the second UE can act as a relay between the first UE and the base station. The first UE can use the discovery process to discover the second UE without assistance from the base station. Summary of the Invention

[0004] The following is a summary of one or more aspects of the present disclosure in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all anticipated features of the present disclosure and is neither intended to identify key or important elements of all aspects of the present disclosure nor to delineate the scope of any or all aspects of the present disclosure. Its sole purpose is to present some concepts of one or more aspects of the present disclosure in some form as a prelude to the more detailed description that will be presented later.

[0005] In one example, a discovery method in a wireless communication network is disclosed. The method includes: determining to use a service associated with bypass communication; determining content of a discovery message including an indication that the message is a discovery message for the service; determining a bypass resource for sending the discovery message; and sending the discovery message including an indication that the message is a discovery message for the service via a user plane using the determined bypass resource.

[0006] In another example, a user equipment (UE) in a wireless communication network is disclosed. The UE includes a wireless transceiver, a memory, and a processor communicatively coupled to the wireless transceiver and the memory. In one aspect, the processor and the memory are configured to determine to use a service associated with bypass communication, determine content of a discovery message including an indication that the message is a discovery message for the service, determine bypass resources for sending the discovery message, and send the discovery message including an indication that the message is a discovery message for the service via a user plane using the determined bypass resources.

[0007] In another example, a user equipment (UE) in a wireless communication network is disclosed. According to one aspect, the wireless communication device includes: means for determining to use a service associated with bypass communication; means for determining content of a discovery message including an indication that the message is a discovery message for the service; means for determining bypass resources for sending the discovery message; and means for sending the discovery message including an indication that the message is a discovery message for the service via a user plane using the determined bypass resources.

[0008] In another example, an article of manufacture for use by a user equipment (UE) in a wireless communication network is disclosed. The article of manufacture includes a non-transitory computer-readable medium having stored therein instructions executable by one or more processors of the UE. According to one aspect, the instructions include instructions for determining to use a service associated with bypass communication, determining content of a discovery message including an indication that the message is a discovery message for the service, determining bypass resources for sending the discovery message, and sending the discovery message including an indication that the message is a discovery message for the service over a user plane using the determined bypass resources.

[0009] By reading the detailed description below, these and other aspects of the present invention will be more fully understood. By reading the following description of specific exemplary embodiments in conjunction with the accompanying drawings, other aspects, features and embodiments will become apparent to those of ordinary skill in the art. Although features can be discussed with respect to certain embodiments and the accompanying drawings below, all embodiments can include one or more advantageous features discussed herein. In other words, although one or more embodiments can be discussed as having certain advantageous features, one or more such features can also be used according to the various embodiments discussed herein. In a similar manner, although exemplary embodiments can be discussed below as device, system or method embodiments, it should be understood that such exemplary embodiments can be implemented in various devices, systems and methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic diagram of a wireless communication system according to some aspects of the present disclosure.

[0011] Figure 2 is a schematic diagram of an example of a radio access network (RAN) according to some aspects of the present disclosure.

[0012] Figure 3 is an illustration of an example of a wireless communication network configured to support direct communication, such as device-to-device (D2D) (eg, bypass) communication, in accordance with some aspects of the present disclosure.

[0013] Figure 4 is a diagram illustrating organizing wireless resources in an air interface using orthogonal frequency division multiplexing (OFDM) according to some aspects of the present disclosure.

[0014] Figure 5 is a diagram illustrating an example of a radio protocol architecture for user and control planes according to some aspects of the present disclosure.

[0015] Figure 6 is a call flow diagram illustrating a first relay process, referred to as a layer 2 (L2) relay process, according to some aspects of the present disclosure.

[0016] Figure 7 is a call flow diagram illustrating a second relay procedure, referred to as a layer 3 (L3) relay procedure, according to some aspects of the present disclosure.

[0017] Figure 8 is a call flow diagram depicting a Model A discovery process according to some aspects of the present disclosure.

[0018] Figure 9 is a call flow diagram depicting a Model B discovery process 800 according to some aspects of the present disclosure.

[0019] Figure 10 is a diagram illustrating a first pair of user plane protocol stacks for a first UE and a second UE and an exemplary first data structure and an exemplary second data structure according to some aspects of the present disclosure.

[0020] Figure 11 is a diagram illustrating a second pair of user plane protocol stacks of a first UE and a second UE and an exemplary third data structure according to some aspects of the present disclosure.

[0021] Figure 12 is a diagram illustrating a third pair of user plane protocol stacks of a first UE and a second UE and exemplary first and second data structures according to some aspects of the present disclosure.

[0022] Figure 13 is a diagram illustrating a fourth pair of user plane protocol stacks of a first UE and a second UE and an exemplary third data structure according to some aspects of the present disclosure.

[0023] Figure 14 is a block diagram illustrating an example of a hardware implementation of a remote UE and / or a relay UE configured for PC5 communications, employing a processing system, according to some aspects of the present disclosure.

[0024] Figure 15 is a flow chart illustrating a first exemplary process (eg, method) at a remote UE configured for PC5 communications according to some aspects of the present disclosure.

[0025] Figure 16 is a flow chart illustrating a second exemplary process (eg, method) at a relay UE configured for PC5 communications according to some aspects of the present disclosure.

[0026] Figure 17 is a flow chart illustrating a third exemplary process (eg, method) at a relay UE configured for PC5 communications according to some aspects of the present disclosure. DETAILED DESCRIPTION

[0027] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details intended to provide a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some cases, well-known structures and components are shown in block diagram form to avoid obscuring the concepts.

[0028] While aspects and embodiments are described in this application by illustration to some examples, those skilled in the art will understand that additional implementations and use cases can come about in many different arrangements and scenarios. Innovations described herein can be implemented across many differing platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, embodiments and / or uses can come about via integrated chip embodiments and other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchasing devices, medical devices, AI-enabled devices, etc.). While some examples can or can not be specific to use cases or applications, the variety of uses and applicability of the described innovations should be apparent. Implementation can range from chip-level or modular components to non-modular, non-chip-level implementations, and further to aggregate, distributed, or OEM devices or systems that incorporate one or more aspects of the described innovations. In some physical settings, devices incorporating described aspects and features can also necessarily include additional components and features for implementation and practice of the claimed and described embodiments. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes (e.g., hardware components including antennas, RF chains, power amplifiers, modulators, buffers, processor(s), interleavers, adders / summers, etc.). It is intended that innovations described herein can be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, end-user devices, etc. of varying sizes, shapes, and constitution.

[0029] One example of an air interface for direct device-to-device (D2D) (e.g., UE-to-UE, one-to-one) discovery and communication is the PC5 interface. The PC5 interface is a reference point between ProSe-enabled UEs for ProSe direct discovery and ProSe direct communication. ProSe direct discovery is a procedure by which a ProSe-enabled UE discovers other ProSe-enabled UEs in its vicinity using only the capabilities of the two UEs with Evolved Universal Terrestrial Radio Access (E-UTRA) technology. In contrast, ProSe discovery is a procedure to identify ProSe-enabled UEs in the vicinity of other UEs using E-UTRA or Evolved Packet Core (EPC). ProSe direct communication is a communication between two or more ProSe-enabled UEs in proximity, by means of user plane transmission via a path that does not traverse any network node using E-UTRA technology.

[0030] The PC5 interface can also be used for bypass communication between UEs, such as within New Radio (NR) V2X. The PC5 interface may include three planes. The discovery plane of the PC5 interface (referred to herein as PC5-D) can be used by a UE to directly discover other UEs in the vicinity. The signaling plane of the PC5 interface (referred to herein as PC5-S) can be used for control plane signaling on the PC5 interface to establish, maintain, and release a secure direct link between two UEs. The user plane of the PC5 interface (referred to herein as PC5-U) can be used to send user data directly between two UEs.

[0031] The protocol stack includes a protocol stack one after another for supporting control plane and user plane functions between two or more entities. These entities can be, for example, UEs, base stations (e.g., eNBs, gNBs), serving gateways, packet data network gateways, or ProSe functions. In some examples, the various protocol stacks can, for example, control the configuration of ProSe-enabled UEs, control ProSe direct discovery, or control the exchange of user data between UEs. For example, a control plane protocol stack can be used for a PC5 discovery (PC5-D) interface between two UEs. However, this protocol stack is only defined for the control plane. A user plane protocol stack for NR discovery between two UEs using the PC5 discovery protocol can, for example, provide more discovery opportunities than discovery in the control plane. Currently; however, there is no user plane protocol stack for NR discovery.

[0032] The various concepts presented throughout this disclosure can be implemented across a variety of telecommunication systems, network architectures, and communication standards. Figure 1 As a non-limiting illustrative example, various aspects of the present disclosure are described with reference to a wireless communication system 100. The wireless communication system 100 includes three interacting domains: a core network 102, a radio access network (RAN) 104, and a user equipment (UE) 106. By means of the wireless communication system 100, the UE 106 can perform data communications with an external data network 110 (such as (but not limited to) the Internet).

[0033] The RAN 104 may implement any suitable radio access technology (RAT), or RAT, to provide wireless access to the UE 106. As an example, the RAN 104 may operate in accordance with the 3rd Generation Partnership Project (3GPP) New Radio (NR) specifications, commonly referred to as 5G. As another example, the RAN 104 may operate under a mix of 5G NR and Evolved Universal Terrestrial Radio Access Network (eUTRAN) standards, commonly referred to as LTE. 3GPP refers to such a hybrid RAN as a next-generation RAN, or NG-RAN. In another example, the RAN 104 may operate in accordance with both LTE and 5G NR standards. Of course, many other examples may be utilized within the scope of this disclosure.

[0034] As shown, the RAN 104 includes multiple base stations 108. Broadly speaking, a base station is a network element in a radio access network that is responsible for radio transmission and reception to and from the UE 106 in one or more cells. A base station may be referred to variously by those skilled in the art as a base transceiver station (BTS), a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), an access point (AP), a Node B (NB), an eNode B (eNB), a gNode B (gNB), or some other appropriate terminology in different technologies, standards, or contexts. In an example where the RAN 104 operates according to LTE and 5G NR standards, one of the base stations 108 may be an LTE base station, while the other may be a 5G NR base station.

[0035] RAN 104 is also shown as supporting wireless communications for multiple mobile devices. In the 3GPP standard, a mobile device may be referred to as a user equipment (UE) 106, but may also be referred to as a mobile station (MS), a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal (AT), a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology by those skilled in the art. UE 106 may be equipment that provides network service access to a user. In an example where RAN 104 operates according to LTE and 5G NR standards, UE 106 may be an Evolved Universal Terrestrial Radio Access Network-New Air Interface Dual Connectivity (EN-DC) UE that is capable of being simultaneously connected to an LTE base station and an NR base station to receive data packets from both the LTE base station and the NR base station.

[0036] In this document, a "mobile" device does not necessarily have the ability to move and can be stationary. The term mobile device or mobile device refers broadly to a variety of devices and technologies. A UE may include multiple hardware structural components whose size, shape, and arrangement facilitate communication; such components may include antennas, antenna arrays, antenna array modules, RF chains, amplifiers, one or more processors, etc. electrically coupled to each other. For example, some non-limiting examples of mobile devices include mobile phones, cellular (mobile) phones, smartphones, Session Initiation Protocol (SIP) phones, laptops, personal computers (PCs), notebooks, netbooks, smartbooks, tablets, personal digital assistants (PDAs), and various embedded systems, such as those corresponding to "Internet of Things" (IoT) systems and / or devices. A mobile device may also be a car or other transportation vehicle, a remote sensor or actuator, a robot or robotic device, a satellite radio, a global positioning system (GPS) device, an object tracking device, a drone, a multicopter, a quadcopter, a remote control device, a consumer and / or wearable device such as glasses, a wearable camera, a virtual reality device, a smartwatch, a health or fitness tracker, a digital audio player (e.g., an MP3 player), a camera, a game console, etc. Mobile equipment may also be digital home or smart home devices, such as home audio, video and / or multimedia devices, appliances, vending machines, smart lighting, home security systems, smart meters, etc. Mobile equipment may also be smart energy devices, security devices, solar panels or solar arrays, municipal infrastructure equipment that controls power (e.g., smart grids), lighting, water, etc.; industrial automation and enterprise equipment; logistics managers; agricultural equipment; military defense equipment, vehicles, aircraft, ships, and weapons, etc. In addition, mobile devices can provide connected medical or telemedicine support, that is, remote health care. Telehealth devices may include remote health monitoring devices and remote health management devices, whose communications may be given priority treatment or priority access over other types of information, for example, in terms of priority access to critical service data transmission and / or associated QoS for critical service data transmission.

[0037] The wireless communication between the RAN 104 and the UE 106 can be described as utilizing an air interface. Transmissions from a base station (e.g., base station 108) to one or more UEs (e.g., UE 106) over the air interface can be referred to as downlink (DL) transmissions. According to certain aspects of the present disclosure, the term downlink can refer to point-to-multipoint transmissions initiated at a scheduling entity (further described below; e.g., base station 108). Another way to describe this scheme can be to use the term broadcast channel multiplexing. Transmissions from a UE (e.g., UE 106) to a base station (e.g., base station 108) can be referred to as uplink (UL) transmissions. According to other aspects of the present disclosure, the term uplink can refer to point-to-point transmissions initiated at a scheduled entity (further described below; e.g., UE 106).

[0038] In some examples, access to the air interface can be scheduled, wherein a scheduling entity (e.g., base station 108) allocates resources (e.g., time-frequency resources) for communications between some or all devices and apparatuses within its service area or cell. In the present disclosure, as discussed further below, a scheduling entity can be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more scheduled entities. That is, for scheduled communications, a UE 106, which can be a scheduled entity, can utilize resources allocated by the scheduling entity 108.

[0039] The base stations represented by scheduling entity 108 in both the singular and plural are not the only entities that can serve as scheduling entities. That is, in some examples, a UE can serve as a scheduling entity, scheduling resources for one or more scheduled entities (e.g., one or more other UEs). As discussed in more detail below, a UE can communicate directly with other UEs in a peer-to-peer manner and / or in a relay configuration. For example, UE 122 is shown communicating with UE 106 via direct link signals (e.g., bypass 124). In conjunction with Figure 2 Additional examples of direct link signals are provided.

[0040] like Figure 1 As shown, the scheduling entity 108 can broadcast downlink traffic 112 to one or more scheduled entities 106. Broadly speaking, the scheduling entity 108 is a node or device responsible for scheduling traffic in the wireless communication network, including downlink traffic 112 and, in some examples, uplink traffic 116 from one or more scheduled entities 106 to the scheduling entity 108. On the other hand, the scheduled entity 106 is a node or device that receives downlink control 114, which includes but is not limited to scheduling information (e.g., grants), synchronization or timing information, downlink control information (DCI), or other control information from another entity in the wireless communication network, such as the scheduling entity 108.

[0041] In addition, uplink and / or downlink control and / or traffic can be time-divided into frames, subframes, time slots and / or symbols. As used herein, a symbol can refer to a time unit in an orthogonal frequency division multiplexing (OFDM) waveform in which each subcarrier carries a resource element (RE). A time slot can carry 7 or 14 OFDM symbols. A subframe can refer to a duration of 1ms. Multiple subframes or time slots can be grouped together to form a single frame or radio frame. Of course, these definitions are not required, and any suitable scheme for organizing a waveform can be utilized, and the various time divisions of a waveform can have any suitable duration.

[0042] Typically, base stations 108 may include a backhaul interface for communicating with the backhaul 120 portion of wireless communication system 100. Backhaul 120 may provide a link between base stations 108 and core network 102. Additionally, in some examples, the backhaul network may provide interconnectivity between base stations 108. Various types of backhaul interfaces may be used, such as a direct physical connection using any suitable transport network, a virtual network, and the like.

[0043] The core network 102 can be part of the wireless communication system 100 and can be independent of the radio access technology used in the RAN 104. In some examples, the core network 102 can be configured according to 5G standards (e.g., 5GC). In other examples, the core network 102 can be configured according to 4G Evolved Packet Core (EPC) or any other suitable standard or configuration.

[0044] Figure 2 is a diagram of an example of a radio access network (RAN) 200 according to some aspects of the present disclosure. In some examples, the RAN 200 can be used with the RAN described above and Figure 1 The geographic area covered by the RAN 200 may be divided into cellular regions (cells), which may be uniquely identified by a user equipment (UE) based on an identity broadcast from an access point or base station. Figure 2 Macro cells 202, 204, and 206, and small cell 208 are shown, each of which may include one or more sectors (not shown). A sector is a sub-area of ​​a cell. All sectors within a cell are served by the same base station. A radio link within a sector may be identified by a single logical identifier belonging to that sector. In a cell divided into sectors, multiple sectors within the cell may be formed by antenna groups, where each antenna is responsible for communicating with UEs in a portion of the cell.

[0045] Various arrangements of base stations can be used. Figure 2In the example shown, two base stations 210 and 212 are shown in cells 202 and 204, and a third base station 214 controls a remote radio head (RRH) 216 in cell 206. That is, a base station can have an integrated antenna, or can be connected by feeders to an antenna or RRH 216. In the example shown, cells 202, 204, and 206 can be referred to as macro cells because base stations 210, 212, and 214 support cells with large sizes. Further, a base station 218 is shown in a small cell 208 (e.g., a microcell, picocell, femtocell, home base station, home node B, home eNode B, etc.), which can overlap with one or more macrocells. In this example, cell 208 can be referred to as a small cell because base station 218 supports a cell with a relatively small size. The cell size can be determined based on system design as well as component constraints.

[0046] It should be appreciated that the RAN 200 can include any number of wireless base stations and cells. Further, a relay node can be deployed to extend the size or coverage area of a given cell. The base stations 210, 212, 214, 218 provide wireless access points to a core network for any number of mobile Figure 1 stations 210, 212, 214, and / or 218 can be the same or similar to the base station / scheduling entity 108 described above and shown in FIG. 1.

[0047] Figure 2 A quadcopter or drone 220 is also included, which can be configured to function as a base station. That is, in some examples, a cell is not necessarily stationary, and the geographic area of a cell can move based on the location of a mobile base station, such as the quadcopter or drone 220.

[0048] Within the RAN 200, a cell can include UEs that can be in communication with one or more sectors of each cell. Further, each base station 210, 212, 214, 218, and 220 can be configured to provide an access point to the core network 102 (see Figure 1 ) for all the UEs in the individual cells. For example, UEs 222 and 224 can be in communication with the base station 210; UEs 226 and 228 can be in communication with the base station 212; UEs 230 and 232 can be in communication with the base station 214 through the RRH 216; UE 234 can be in communication with the base station 218; and UE 236 can be in communication with the mobile base station 220. In some examples, the UEs 222, 224, 226, 228, 230, 232, 234, 236, 238, 240, and / or 242 can be the same or similar to the UE 106 described above and shown in FIG. 1. Figure 1

[0049] ​In some examples, mobile network nodes (e.g., unmanned aerial vehicles (UAVs) such as quadcopters or drones 220) can be configured to function as UEs. For example, quadcopters or drones 220 can operate within cell 202 by communicating with base station 210.

[0050] The air interface in the RAN 200 can utilize one or more multiplex and multiple access algorithms to enable simultaneous communication of various devices on the same spectrum. For example, 5G NR specifications utilize orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) (also referred to as orthogonal frequency divisional multiplexing (OFDM)) to provide multiplexing and multiple access for UL transmissions from a UE 222 and 224 to base station 210 and for DL transmissions from base station 210 to one or more UEs 222 and 224. Additionally, for UL transmissions, 5G NR specifications provide support for discrete Fourier transform-spread-OFDM (DFT-s-OFDM) with a CP, also referred to as single-carrier FDMA (SC-FDMA). However, within the scope of the present disclosure, multiplexing and multiple access are not limited to the above schemes and can be provided, for example, utilizing time division multiple access (TDMA), code division multiple access (CDMA), frequency division multiple access (FDMA), sparse code multiple access (SCMA), resource spread multiple access (RSMA), or other suitable multiple access schemes. Further, multiplexing for DL transmissions from a base station 210 to a UE 222 and 224 can be provided utilizing time division multiplexing (TDM), code division multiplexing (CDM), frequency division multiplexing (FDM), orthogonal frequency division multiplexing (OFDM), sparse code multiplexing (SCM), or other suitable multiplexing schemes.

[0051] Further, the air interface in the RAN 200 can utilize one or more duplex algorithms. Duplex refers to a point-to-point communication link where both endpoints can communicate with one another. Full duplex means both endpoints can communicate with one another simultaneously. Half duplex means only one endpoint can send information to the other endpoint at a time. In a wireless link, a full duplex channel generally relies on physical isolation between transmitter and receiver, as well as suitable interference cancellation technologies. Full duplex emulation is commonly achieved in wireless links by utilizing frequency or time division duplex (FDD or TDD). In FDD, different carrier frequencies are used for different directions of communication. In TDD, the same carrier frequency is used for different directions of communication, with different

[0052] In the RAN 200, the ability for a UE to communicate while moving, independent of its location, is referred to as mobility. The various physical channels between the UE and the RAN 200 are generally set-up for the duration of a communication session with only periodic updates of the channel as the UE moves from one place to another. However, in some Figure 1The AMF is established, maintained and released under the control of the core network 102), and the AMF may include a security context management function (SCMF) that manages the security context of both the control plane and the user plane functions and a security anchor function (SEAF) that performs authentication.

[0053] RAN 200 can utilize either DL-based mobility or UL-based mobility to implement mobility and handover (i.e., transferring a UE's connection from one radio channel to another). In a network configured for DL-based mobility, during a call with a scheduling entity, or at any other time, a UE can monitor various parameters of the signal from its serving cell and various parameters of neighboring cells. Based on the quality of these parameters, the UE can maintain communication with one or more neighboring cells. During this time, if the UE moves from one cell to another, or if the signal quality from a neighboring cell exceeds the signal quality from the serving cell for a given amount of time, the UE can perform a handover, or handover, from the serving cell to the neighboring (target) cell. For example, UE 224 (illustrated as a vehicle, although any suitable form of UE may be used) can move from the geographic area corresponding to its serving cell 202 to the geographic area corresponding to neighboring cell 206. When the signal strength or quality from neighboring cell 206 exceeds the signal strength or quality of its serving cell 202 for a given amount of time, UE 224 can send a report message to its serving base station 210 indicating this. In response, UE 224 may receive a handover command, and the UE may proceed with handover to cell 206 .

[0054] In a network configured for UL-based mobility, the UL reference signal from each UE can be used by the network to select a serving cell for each UE. In some examples, base stations 210, 212, and 214 / 216 can broadcast a unified synchronization signal (e.g., a unified primary synchronization signal (PSS), a unified secondary synchronization signal (SSS), and a unified physical broadcast channel (PBCH)). UEs 222, 224, 226, 228, 230, and 232 can receive the unified synchronization signal, derive carrier frequency and slot timing from the synchronization signal, and send an uplink pilot or reference signal in response to the derived timing. The uplink pilot signal sent by a UE (e.g., UE 224) can be received concurrently by two or more cells within the RAN 200 (e.g., base stations 210 and 214 / 216). Each cell can measure the strength of the pilot signal, and the radio access network (e.g., one or more of base stations 210 and 214 / 216 and / or a central node within the core network) can determine the serving cell of UE 224. As UE 224 moves through RAN 200, the network may continue to monitor the uplink pilot signals transmitted by UE 224. When the signal strength or quality of the pilot signals measured by the neighboring cell exceeds the signal strength or quality measured by the serving cell, the network may handover UE 224 from the serving cell to the neighboring cell, with or without notifying UE 224.

[0055] Although the synchronization signals transmitted by base stations 210, 212, and 214 / 216 may be uniform, the synchronization signals may not identify a specific cell, but may identify a region of multiple cells operating at the same frequency and / or the same timing. The use of regions in 5G networks or other next-generation communication networks implements an uplink-based mobility framework and improves the efficiency of both the UE and the network because the number of mobility messages that need to be exchanged between the UE and the network can be reduced.

[0056] As above combined Figure 1As described above, a base station is not the only entity that can act as a scheduling entity. That is, in some examples, a UE can act as a scheduling entity, scheduling resources for one or more scheduled entities (e.g., one or more other UEs). For example, UE 238 is shown communicating with UEs 240 and 242. In some examples, UE 238 acts as the scheduling entity, while UEs 240 and 242 act as scheduled entities. In other examples, bypass or other types of direct link signals can be transmitted directly between UEs without relying on scheduling or control information from another entity. In one example, two or more UEs (e.g., UEs 226 and 228) can communicate with each other using direct link signals 227 (e.g., bypass, Bluetooth, and / or other types of direct link signals) without relaying the communication through a base station (e.g., base station 212). In another example, UEs 238, 240, and 242 can communicate via direct links in device-to-device (D2D), peer-to-peer (P2P), vehicle-to-vehicle (V2V) networks, vehicle-to-everything (V2X), and / or mesh networks. In the mesh network example, in addition to communicating with a scheduling entity (eg, UE 238), UEs 240 and 242 may optionally communicate directly with each other.

[0057] In some examples, UE 238 may be a transmitting bypass device that reserves resources on a bypass carrier for transmission of bypass signals in a D2D or V2X network to UEs 240 and 242. Here, UEs 240 and 242 are each receiving bypass devices. UEs 240 and 242 may then reserve additional resources on the bypass carrier for subsequent bypass transmissions.

[0058] In other examples, UEs 238, 240, and 242 may be P2P devices (e.g., Bluetooth, Zigbee, or Near Field Communication (NFC) devices) that communicate via a P2P carrier. For example, UEs 238, 240, and 242 may be Bluetooth devices that communicate via a shortwave (e.g., 2.45 GHz) carrier. Each Bluetooth device (e.g., UEs 238, 240, and 242) may operate at low power (e.g., 100 mW or less) to communicate over a short distance (e.g., 10 meters or less). In a Bluetooth network, UEs 238, 240, and 242 may form an ad hoc piconet, and each pair of UEs (e.g., UEs 238 and 240; UEs 238 and 242; and UEs 240 and 242) may communicate on different frequencies in a frequency hopping manner. In a piconet, one of the UEs (e.g., UE 238) can act as a master device, while the other UEs (e.g., UEs 240 and 242) can act as slave devices. Each of the UEs 238, 240, and 242 can automatically detect and connect to each other.

[0059] In some examples, two or more UEs (e.g., UEs 226 and 228) within the coverage area of ​​a serving base station, such as base station 212, can communicate with base station 212 using cellular signals and communicate with each other using direct link signals 227 (e.g., bypass, Bluetooth, and / or other types of direct link signals) without relaying the communications through base station 212. In the example of a V2X network within the coverage area of ​​base station 212, one or both of base station 212 and / or UEs 226 and 228 can serve as a scheduling entity to schedule bypass communications between UEs 226 and 228.

[0060] The two main technologies that can be used by V2X networks include dedicated short-range communications (DSRC) based on the IEEE 802.11p standard and cellular V2X based on LTE and / or 5G (New Radio) standards. Various aspects of the present disclosure may relate to New Radio (NR) cellular V2X networks, which for simplicity will be referred to herein as V2X networks. However, it should be understood that the concepts disclosed herein may not be limited to a specific V2X standard or may be directed to direct link (e.g., bypass) networks other than V2X networks.

[0061] Figure 3 300 is a diagram of an example of a wireless communication network 300 configured to support direct communications, such as device-to-device (D2D) (e.g., bypass) communications, in accordance with aspects of the present disclosure. In some examples, bypass communications may include V2X communications. V2X communications involve not only direct wireless information exchange between vehicles (e.g., vehicles 302 and 304) themselves, but also direct information exchange between vehicles 302 / 304 and infrastructure 306, such as streetlights, buildings, traffic cameras, toll booths, or other fixed objects, vehicles 302 / 304 and mobile devices of pedestrians / cyclists 308, and vehicles 302 / 304 and a wireless communication network (e.g., base station 310). In some examples, V2X communications may be implemented in accordance with the New Radio (NR) cellular V2X standard defined by 3GPP Release 16 or other suitable standards.

[0062] V2X transmissions can include, for example, unicast transmissions, groupcast transmissions, and broadcast transmissions. Unicast describes, for example, a transmission from a vehicle (e.g., vehicle 302) to one other vehicle (e.g., vehicle 304). Multicast occurs when a group of UEs (e.g., vehicles 302 and 304) forms a cluster. Data can be multicast within the cluster. Broadcast describes a transmission from, for example, a UE (e.g., vehicle 302) to surrounding receivers near the transmitting UE (e.g., vehicle 304, infrastructure 306 (e.g., RSU), pedestrian / cyclist's mobile device 308, a base station 310 of the network, or any combination thereof).

[0063] V2X communication enables vehicles 302 and 304 to obtain information related to weather, nearby accidents, road conditions, nearby vehicle and pedestrian activity, objects near the vehicle, and other relevant information that can be used to improve the vehicle driving experience and increase vehicle safety. For example, such V2X data can enable autonomous driving and improve road safety and traffic efficiency. For example, V2X-connected vehicles 302 and 304 can use the exchanged V2X data to provide in-vehicle collision warnings, road hazard warnings, approaching emergency vehicle warnings, pre- / post-collision warnings and information, emergency braking warnings, forward traffic jam warnings, lane change warnings, intelligent navigation services, and other similar information. In addition, V2X data received by the V2X-connected mobile device of pedestrians / cyclists 308 can be used to trigger warning sounds, vibrations, flashing lights, etc. to prevent imminent danger.

[0064] The bypass communication between the vehicles 302 and 304 or between the vehicle 302 or 304 and the infrastructure 306 or the pedestrian / cyclist 308 or between the two UEs 314 and 318 occurs via the proximity service (ProSe) PC5 interface 312. In various aspects of the present disclosure, the PC5 interface 312 or other direct interfaces can also be used to support D2D communication under other proximity use cases. Examples of other proximity use cases may include proximity services based on public safety or business (e.g., entertainment, education, office, medical and / or interaction). Figure 3 In the example shown, direct (eg, ProSe) communication may occur between UEs 314 and 316 and between UEs 314 and 318 .

[0065] ProSe communication can support different operation scenarios, such as in-coverage, out-of-coverage, and partial coverage. Figure 3In FIG, the air interface coverage area 320 of the base station 310 is represented by a dotted ellipse. Out-of-coverage refers to a scenario where the UE 318 is outside the air interface coverage area 320 of the base station 310, but is still configured for ProSe communication. Another example of an out-of-coverage scenario is if the UEs 314 and 316 are outside the coverage area 320 of the base station 310, but each UE is still configured for ProSe communication (the coverage configuration is not in FIG). Figure 3 318). Partial coverage refers to a scenario in which one UE (e.g., UE 318) is outside the air interface coverage area 320 (also referred to as coverage area 320) of a base station (e.g., base station 310), while another UE (e.g., UE 314) is within the coverage area 320 of the base station 310 and communicates with the base station 310. UEs 314 and 318 may communicate via a bypass through a PC5 312 interface. In such a configuration, UE 314 may function as a relay UE to relay user data and control signal traffic to and from UE 318, which may be referred to as a remote UE. In-coverage refers to a scenario in which UEs 314 and 316 communicate with the base station 310 (e.g., gNB) via a Uu 322 (e.g., cellular interface) connection to receive ProSe service authorization and provisioning information to support ProSe operations.

[0066] Various aspects of the present disclosure will be described with reference to OFDM waveforms, Figure 4 An example of an OFDM waveform is schematically shown in FIG. Those skilled in the art will appreciate that various aspects of the present disclosure can be applied to a discrete Fourier transform-spread spectrum OFDM (DFT-s-OFDM) waveform with a CP (also known as a single-carrier FDMA (SC-FDMA)) in substantially the same manner as described below. That is, while some examples of the present disclosure may focus on an OFDM link for clarity, it will be appreciated that the same principles can also be applied to SC-FDMA waveforms.

[0067] In this disclosure, a frame refers to a duration of 10ms used for wireless transmission, each frame includes 10 subframes, each subframe is 1ms. A transmission burst may include multiple frames. On a given carrier, there may be one set of frames in the UL and another set of frames in the DL. Now refer to Figure 4 , shows an expanded view of an example frame 402, illustrating an OFDM resource grid. However, as those skilled in the art will readily appreciate, the PHY transmission structure used for any particular application may differ from the example described herein, depending on many factors. Here, time is shown horizontally in units of OFDM symbols; frequency is shown vertically in units of subcarriers or tones.

[0068] Resource grid 404 can be used to schematically represent the time-frequency resources for a given antenna port. That is, in a multiple-input, multiple-output (MIMO) implementation with multiple available antenna ports, corresponding multiple resource grids 404 can be used for communication. Resource grid 404 is divided into multiple resource elements (REs) 406. An RE is 1 subcarrier x 1 symbol, the smallest discrete portion of the time-frequency grid, containing a single complex value representing data from a physical channel or signal. Depending on the modulation used in a particular implementation, each RE can represent one or more information bits. In some examples, a block of REs can be referred to as a physical resource block (PRB) or more simply a resource block (RB) 408, which contains any suitable number of consecutive subcarriers in the frequency domain. In one example, an RB can include 12 subcarriers, independent of the parametrics used. In some examples, depending on the parametrics, an RB can include any suitable number of consecutive OFDM symbols in the time domain. In this disclosure, it is assumed that a single RB, such as RB 408, corresponds entirely to a single communication direction (whether transmitting or receiving for a given device).

[0069] A collection of contiguous or non-contiguous resource blocks may be referred to herein as a resource block group (RBG), subband, or bandwidth part (BWP). A collection of subbands or BWPs may span the entire bandwidth. Scheduling a UE (scheduled entity) for downlink or uplink transmission typically involves scheduling one or more resource elements 406 within one or more subbands or bandwidth parts (BWPs). Consequently, a UE typically utilizes only a subset of the resource grid 404. An RB may be the smallest unit of resources that can be allocated to a UE. Therefore, the more RBs scheduled for a UE, the higher the modulation scheme selected for the air interface, and the higher the data rate for the UE.

[0070] In this illustration, RB 408 is shown as occupying less than the entire bandwidth of subframe 402, with some subcarriers shown above and below RB 408. In a given implementation, subframe 402 may have a bandwidth corresponding to any number of one or more RBs 408. Furthermore, in this illustration, RB 408 is shown as occupying less than the entire duration of subframe 402, although this is merely one possible example.

[0071] Each subframe 402 (e.g., a 1 ms subframe) may be composed of one or more adjacent time slots. Figure 4In the illustrative example shown, a subframe 402 includes four time slots 410. In some examples, a time slot can be defined based on a specified number of OFDM symbols with a given cyclic prefix (CP) length. For example, a time slot can include 7 or 14 OFDM symbols with a nominal CP. Additional examples may include mini-slots with shorter durations (e.g., one to three OFDM symbols), sometimes referred to as shortened transmission time intervals (TTIs). In some cases, these mini-slots or shortened TTIs can be sent using resources scheduled for ongoing time slot transmissions for the same or different UEs. Any number of resource blocks can be used within a subframe or time slot.

[0072] An expanded view of a time slot 410 shows the time slot 410 as including a control region 412 and a data region 414. In a first example of the time slot 410, the control region 412 may carry a control channel (e.g., a physical downlink control channel (PDCCH)), and the data region 414 may carry a data channel (e.g., a physical downlink shared channel (PDSCH)). In a second example of the time slot 410, the control region 412 may carry a control channel (e.g., a physical uplink control channel (PUCCH)), and the data region 414 may carry a data channel (e.g., a physical uplink shared channel (PUSCH)). Of course, a time slot may include all DL, all UL, or at least one DL portion and at least one UL portion. Figure 4 The structure shown in is merely exemplary in nature and different slot structures may be utilized and may include one or more of each of the control region(s) and data region(s).

[0073] although Figure 4 Although not shown, each RE 406 within an RB 408 may be scheduled to carry one or more physical channels, including a control channel, a shared channel, a data channel, etc. Other REs 406 within an RB 408 may also carry pilot or reference signals, including but not limited to a demodulation reference signal (DMRS), a control reference signal (CRS), a channel state information reference signal (CSI-RS), and / or a sounding reference signal (SRS). These pilot or reference signals may be provided to a receiving device to perform channel estimation of the corresponding channel, which may enable coherent demodulation / detection of the control and / or data channels within the RB 408.

[0074] In some examples, time slot 410 can be used for broadcast or unicast communication. For example, broadcast, multicast, or groupcast communication can refer to point-to-multipoint transmission from one device (e.g., a base station, UE, or other similar device) to other devices. As used herein, broadcast communication is delivered to all devices, while multicast communication is delivered to multiple intended receiving devices. Unicast communication can refer to point-to-point transmission from one device to a single other device.

[0075] In a DL transmission, a transmitting device (e.g., a base station / scheduling entity 108) may allocate one or more REs 406 (e.g., DL REs within a control region 412) to carry DL control information (DCI) including one or more DL control 114 channels. The one or more DL control 114 channels may carry, for example, information originating from higher layers, such as a physical broadcast channel (PBCH), a physical hybrid automatic repeat request (HARQ) indicator channel (PHICH), a physical downlink control channel (PDCCH), etc., to one or more scheduled entities (e.g., a UE / scheduled entity 106). A physical control format indicator channel (PCFICH) may provide information to assist a receiving device in receiving and decoding the PDCCH and / or the physical HARQ indicator channel (PHICH). The PHICH carries HARQ feedback transmissions, such as acknowledgements (ACKs) or negative acknowledgements (NACKs). HARQ is a technique well known to those skilled in the art, wherein the integrity of packet transmissions may be checked for accuracy at the receiving end, for example, using any suitable integrity checking mechanism, such as a checksum or a cyclic redundancy check (CRC). If the integrity of the transmission is approved, an ACK may be sent, whereas if not, a NACK may be sent. In response to a NACK, the transmitting device may issue a HARQ retransmission, which may enable trace combining, incremental redundancy, etc. The PDCCH may carry downlink control 114, including downlink control information (DCI) for one or more UEs in the cell. This may include, but is not limited to, power control commands, scheduling information, grants, and / or allocation of REs for DL ​​and UL transmissions.

[0076] The base station may also allocate one or more REs 406 to carry other DL signals, such as a demodulation reference signal (DMRS); a phase tracking reference signal (PT-RS); a positioning reference signal (PRS), a channel state information reference signal (CSI-RS); a primary synchronization signal (PSS); and a secondary synchronization signal (SSS). These DL signals (also referred to as downlink physical signals) may correspond to a set of resource elements used by the physical layer, but they generally do not carry information from higher layers. The UE may utilize the PSS and SSS to achieve radio frame, subframe, time slot, and symbol synchronization in the time domain, identify the center of the channel (system) bandwidth in the frequency domain, and identify the physical cell identity (PCI) of the cell. The synchronization signals PSS and SSS, as well as the PBCH and PBCH DMRS in some examples, may be transmitted in a synchronization signal block (SSB). The PBCH may also include a master information block (MIB), which includes various system information and parameters for decoding system information blocks (SIBs). The SIB may be, for example, system information type 1 (SIB1), which may include various additional system information. Examples of system information sent in the MIB may include, but are not limited to, subcarrier spacing, system frame number, configuration of a PDCCH control resource set (CORESET) (e.g., PDCCH CORESET0), and search space for SIB1. Examples of additional system information sent in SIB1 may include, but are not limited to, random access search space, downlink configuration information, and uplink configuration information. The MIB and SIB1 together provide minimal system information (SI) for initial access.

[0077] The synchronization signals PSS and SSS (collectively referred to as SS), and in some examples the PBCH, may be transmitted in an SS block comprising four consecutive OFDM symbols, numbered in ascending order from 0 to 3 via a time index. In the frequency domain, the SS block may extend over 240 consecutive subcarriers, numbered in ascending order from 0 to 239 via a frequency index. Of course, the present disclosure is not limited to this particular SS block configuration. Other non-limiting examples within the scope of the present disclosure may utilize more or less than two synchronization signals; may include one or more supplemental channels in addition to the PBCH; may omit the PBCH; and / or may use discontinuous symbols of the SS block.

[0078] For example, in an UL transmission, a transmitting device (e.g., a UE / scheduled entity 106) may utilize one or more REs 406, including one or more UL control 118 channels that may carry uplink control information (UCI) to the base station / scheduling entity 108. The UCI may include various packet types and categories, including pilots, reference signals, and information configured to implement or assist in decoding uplink data transmissions. In some examples, the uplink control information may include a scheduling request (SR), i.e., a request to the scheduling entity to schedule an uplink transmission. Here, in response to the SR sent from the scheduled entity 106 on the uplink control 118 channel, the scheduling entity 108 may send downlink control information (DCI), which may schedule resources for uplink packet transmission. The UCI may also include HARQ feedback, such as an acknowledgment (ACK) or negative acknowledgment (NACK), channel state information (CSI), channel state feedback (CSF), or any other suitable UL control information (UCI). The UCI may be derived from higher layers via one or more UL control channels, such as the physical uplink control channel (PUCCH), the physical random access channel (PRACH), etc. In addition, the UL RE 406 may carry UL physical signals that typically do not carry information derived from higher layers, such as a demodulation reference signal (DMRS), a phase tracking reference signal (PT-RS), a sounding reference signal (SRS), etc.

[0079] In addition to control information, one or more REs 406 can be allocated for user data traffic (e.g., within the data region 414). Such traffic can be carried on one or more traffic channels, such as, for DL ​​transmissions, the physical downlink shared channel (PDSCH), or for UL transmissions, the physical uplink shared channel (PUSCH). In some examples, one or more REs 406 within the data region 414 can be configured to carry SIBs (e.g., SIB1) that carry information that can enable access to a given cell.

[0080] In an example of bypass communication on a bypass carrier via a PC5 interface, the control region 412 of a timeslot 410 may include a physical bypass control channel (PSCCH), which includes bypass control information (SCI) sent by an initiating (transmitting) bypass device (e.g., a V2X or other bypass device) to a set of one or more other receiving bypass devices. The PSCCH may include HARQ feedback information (e.g., ACK / NACK), which may be used to indicate whether retransmission is required on the bypass. The data region 414 of the timeslot 410 may include a physical bypass shared channel (PSSCH), which includes data sent by the initiating (transmitting) bypass device within resources reserved by the transmitting bypass device on the bypass carrier.

[0081] The physical channels described above are typically multiplexed and mapped onto transport channels for processing at the media access control (MAC) layer. Transport channels carry information blocks called transport blocks (TBs). The transport block size (TBS), which corresponds to the number of information bits, can be a controlled parameter based on the modulation and coding scheme (MCS) and the number of RBs in a given transmission.

[0082] Figure 5 FIGURE 1 is a diagram illustrating an example of a radio protocol architecture for user and control planes according to some aspects of the present disclosure. Figure 5 As shown, the wireless protocol architecture for the UE and base station consists of three layers: Layer 1 (L1), Layer 2 (L2), and Layer 3 (L3). L1 507 is the lowest layer and implements various physical layer signal processing functions. L1 507 will be referred to herein as the physical layer 506. Layer 2 508, located above the physical layer 506, is responsible for the link between the UE and base station at the physical layer 506.

[0083] In the user plane, the L2 layer 508 includes a medium access control (MAC) layer 510, a radio link control (RLC) layer 512, a packet data convergence protocol (PDCP) layer 514, a service data adaptation protocol (SDAP) layer 815, and a PC5 discovery layer 516, which are terminated at the base station on the network side. Although not shown, the UE may have several upper layers above the L2 layer 508, including at least one network layer (e.g., an IP layer and a user data protocol (UDP) layer) and one or more application layers, and the network layer is terminated at the user plane function (UPF) on the network side.

[0084] According to aspects described herein, the PC5 discovery layer 516 can function as, for example, an application layer. The PC5 discovery layer 516 can create (or provide) the content of a PC5 discovery message. The PC5 discovery layer 516 can be a layer of a protocol stack of a user equipment (UE). In some examples, the SDAP layer 515 and the PC5 discovery layer 516 can reside in layer 3 L3 509. As used herein, a discovery message created by the PC5 discovery layer 516 can be referred to as a PC5 discovery message.

[0085] The SDAP layer 515 provides mapping between 5G core (5GC) quality of service (QoS) flows and data radio bearers, and performs QoS flow ID marking in both downlink and uplink packets. The PDCP layer 514 provides packet sequence numbering, in-order delivery of packets, retransmission of PDCP protocol data units (PDUs), and transmission of upper layer data packets to lower layers. PDUs may include, for example, Internet Protocol (IP) packets, Ethernet frames, and other unstructured data (i.e., machine type communications (MTC), hereinafter collectively referred to as "packets"). The PDCP layer 514 also provides header compression for upper layer data packets to reduce radio transmission overhead, security of encrypted data packets, and integrity protection of data packets. The PDCP context may indicate whether PDCP duplication is used for a unicast connection.

[0086] The RLC layer 512 provides segmentation and reassembly of upper layer data packets, error correction through automatic repeat request (ARQ), and sequence numbering independent of PDCP sequence numbering. The RLC context may indicate whether acknowledged mode (e.g., using a reordering timer) or unacknowledged mode is used for the RLC layer 512. The MAC layer 510 provides multiplexing between logical and transport channels. The MAC layer 510 is also responsible for allocating various radio resources (e.g., resource blocks) in a cell between UEs and for HARQ operations. The MAC context may enable, for example, HARQ feedback schemes, resource selection algorithms, carrier aggregation, beam failure recovery, or other MAC parameters for unicast connections. The physical layer 506 is responsible for sending and receiving data on physical channels (e.g., within time slots). A MACSDU may be placed in a MAC PDU for transmission to the physical layer 506 via a transport channel. The PHY context may indicate the transport format and radio resource configuration (e.g., bandwidth part (BWP), parameterology, etc.) for unicast connections.

[0087] In the control plane, for L1 506 and L2 508, the radio protocol architecture of the UE and the base station is basically the same, except that there is no PC5 discovery layer in the control plane and there is no header compression function for the control plane. The control plane also includes the radio resource control (RRC) layer 518 in L3 and the higher non-access stratum (NAS) layer 520. The RRC layer 518 is responsible for establishing and configuring signaling radio bearers (SRBs) and data radio bearers (DRBs) between the base station and the UE, paging initiated by the 5GC or NG-RAN, and broadcasting of system information related to the access stratum (AS) and non-access stratum (NAS). The RRC layer 518 is also responsible for QoS management, mobility management (e.g., handover, cell selection, inter-RAT mobility), UE measurement and reporting, and security functions. The NAS layer 520 terminates at the AMF in the core network and performs various functions such as authentication, registration management, and connection management.

[0088] Described above and in Figure 1-Figure 5 The channels, carriers, and protocol layers shown in the figure are not necessarily all channels, carriers, and protocol layers that can be used between the base station / scheduling entity 108 and the UE / scheduled entity 106. A person skilled in the art will recognize that other channels, carriers, and protocol layers may be used in addition to those shown, such as other traffic, control, and feedback channels.

[0089] In some examples, the PC5-D interface can interact with the MAC layer during discovery. For example, a UE can establish multiple logical channels. Each logical channel can be associated with a logical channel ID (LCID) that uniquely identifies the corresponding logical channel. According to some aspects, the logical channel can transmit PC5 discovery messages. In some examples, the value of the LCID can be used to identify the discovery message as a PC5 discovery message.

[0090] A PC5-implemented UE may utilize a PC5-D interface to broadcast or multicast a discovery message to nearby UEs, the discovery message announcing the availability of PC5-based communications. A PC5-implemented UE may receive responses to the broadcast or multicast discovery message from nearby UEs that are also PC5-implemented. The discovery message may be a PC5 discovery message. Aspects are described herein by which an out-of-coverage UE discovers an in-coverage UE for device-to-device (D2D) communication (or vice versa) via an interface such as a PC5-D interface.

[0091] As reference Figure 3 As described, the term out-of-coverage UE (e.g., UE 318) refers to a UE that is outside of network coverage and, therefore, does not communicate with a core network (such as a 5G core network) via a base station. Therefore, the base station does not schedule resources for the out-of-coverage UE. For example, an out-of-coverage UE may be found when the received signal strength of a physical layer signal received from a base station of the RAN in the downlink and / or sent to a base station of the RAN in the uplink is insufficient to establish or maintain an RRC connection with the RAN. Insufficient power may be due to, for example, distance or obstruction. For example, an out-of-coverage UE may be found at the physical edge of a radio access network (RAN), where the distance from the base station to the physical edge of the RAN takes into account radio path loss. For example, an out-of-coverage UE may be found in a building, subway, or mine, where the walls, roof, and floor of the building, subway, or mine attenuate the radio signal. Other examples of out-of-coverage UEs are also within the scope of the present disclosure. Herein, an out-of-coverage UE may be referred to as a remote UE.

[0092] The term "in-coverage UE" (e.g., UE 314) refers to a UE that is within network coverage and therefore communicates with the core network via a base station. A UE in coverage may be referred to herein as a relay UE. A remote UE (e.g., UE 318) may utilize a single-hop connection with a relay UE (e.g., UE 314), such that the relay UE acts as an intermediate node (e.g., a relay node) between the remote UE and the base station.

[0093] The remote UE may use at least two types of relay procedures to relay user data and control signals to and from the base station through the relay UE. Figure 6 is a call flow diagram illustrating a first relay process, referred to as a layer 2 (L2) relay process 600, in accordance with some aspects of the present disclosure. Figure 6 Entities depicted in FIG6 include a remote UE 602 and a UE-to-network relay UE 604 (referred to herein as relay UE 604). The base station is identified and referred to herein as a next-generation (NG) RAN 606. NG RAN 606 may include a gNB (not shown). Core network 608 is shown as including an access and mobility management function (AMF) 610, a session management function (SMF) 612, and a user plane function (UPF) 614. AMF 610 and SMF 612 employ control plane (e.g., non-access stratum (NAS)) signaling to perform various functions related to mobility management and session management for UEs 602 and 604. For example, AMF 610 provides connectivity, mobility management, and authentication for UEs 602 and 604, while SMF 612 provides session management for UEs 602 and 604 (e.g., handling signaling related to protocol data unit (PDU) sessions between UEs 602 and 604 and external data networks). The UPF 614 provides user plane connectivity to route 5G (NR) packets to / from the UEs 602 and 604 via the NG RAN 606. Those skilled in the art will appreciate that the core network 608 includes many additional nodes and / or functions. These many additional nodes / functions are not depicted to avoid cluttering the drawing.

[0094] The L2 relay process 600 may include, for example, a 5G registration and / or PDU session connection establishment via the NG RAN 606 by the relay UE 604 and the core network 608. If the remote UE 602 is within the coverage area of ​​the NG RAN 606, a similar situation of a 5G registration and / or PDU session connection establishment 616 between the remote UE 602 and the core network 608 via the NG RAN 606 may occur. If the remote UE 602 is not within the coverage area of ​​the NG RAN 606 (e.g., out of coverage), the 5G registration and / or PDU session connection establishment 616 between the remote UE 602 and the core network via the NG RAN 606 may not occur; therefore, this feature is not present in the embodiment of the present invention. Figure 6 Rendered as optional.

[0095] After the relay UE 604 5G registration and / or PDU session connection 616 , the relay UE 604 may perform a relay UE PDU session establishment 620 with the core network 608 .

[0096] According to some aspects disclosed herein, the remote UE 602 may execute or run instructions to cause one or more circuits to perform the UE to network relay UE 604 discovery process 622. Figure 8 and Figure 9 The UE to Network Relay UE 604 discovery process 622 is described more fully herein. Figure 10-13 An example implementation of a UE to network relay UE 604 discovery process 622 is provided.

[0097] The remote UE 602 may issue (e.g., send) an NR RRC connection request 624 to the relay UE 604. The NR RRC connection request 624 may be sent from the remote UE 602 to the relay UE 604 on a bypass broadcast control channel (SBBCH) over a PC5 (also referred to herein as bypass) interface over a PC5 signaling radio bearer (SRB). The relay UE 604 may, in turn, forward 625 the NR RRC connection request 624 to the NG RAN 606.

[0098] The relay UE 604 may optionally establish a new PDU session 626 for the relay node. The previous relay UE PDU session establishment 620 may not be associated with the remote UE 602. The new PDU session may be associated with the remote UE 602.

[0099] Subsequently, in addition to the NR RRC connection request 624, the remote UE 602 may execute or run instructions via the relay UE 604 and the NG RAN 606 to cause one or more circuits to perform an RRC connection and security context establishment 628 with the core network 608. The NG RAN 606 may issue a first RRC reconfiguration message 630 to the remote UE 602. The first RRC reconfiguration message 630 may be sent via the NR UE 604. U The interface is delivered via a signaling radio bearer (SRB) and / or a data radio bearer (DRB) and may include a PC5 logical channel configuration information element (IE). The NG RAN 606 may issue a second RRC reconfiguration message 632 to the relay UE 604. The second RRC reconfiguration message 632 may include a PC5 logical channel configuration information element (IE).

[0100] After receiving the logical channel configuration IE from the NG RAN 606, the remote UE 602 and the relay UE 604 can each configure a PC5 logical channel over which user data and control signals can be transferred. Thus, the remote UE 602 can send user data and control signals 636 (collectively referred to as traffic) to the relay UE 604, and the relay UE 604 can relay the traffic 638 to the UPF 614.

[0101] According to the L2 relay process 600, the remote UE 602 may not need to perform a PC5 unicast link establishment procedure to establish a PC5 unicast link between the remote UE 602 and the relay UE 604 before relaying the service 638. Figure 7 In the L3 relay process explained, a PC5 unicast link establishment process may be performed to obtain the IP address of the remote UE 602. According to the L2 relay process, the remote UE 602 issues an NR RRC configuration message on the PC5 interface via the SBCCH. The NG RAN 606 may independently indicate the PC5 access stratum (AS) configuration to the remote UE 602 and the relay UE 604 via the NR RRC reconfiguration message. According to some aspects, changes to the NR V2X PC5 stack operation may be implemented to support radio bearer processing in NR RRC / PDCP, but not support corresponding logical channels in the PC5 link. According to some aspects, the PC5 RLC may support direct interaction with the NR PDCP. According to some aspects, the relay UE 604 may perform L2 relay.

[0102] Figure 7 is a call flow diagram illustrating a second relay process, referred to as a layer 3 (L3) relay process 700, in accordance with aspects of the present disclosure. Figure 7The depicted entities include a remote UE 702 and a UE-to-Network Relay UE 704 (referred to herein as a relay UE 704). The base stations are identified as and referred to herein as Next Generation (NG) RAN 706. The NG RAN 706 can include gNBs (not shown). As noted above, the core network 708 is represented as including an AMF 710, an SMF 712, and a UPF 714. Those skilled in the art understand that the core network 708 includes many additional nodes and / or functions. These many additional nodes / functions are not described to avoid obscuring the drawing.

[0103] The L3 relay procedure 700 can include, for example, establishment of a 5G registration and / or a PDU session connection by the relay UE 704 and the core network 708 via the NG RAN 706. If the remote UE 702 is within a coverage area of the NG RAN 706, similar cases of establishment of a 5G registration and / or a PDU session connection 716 between the remote UE 702 and the core network 708 via the NG RAN 706 can occur. If the remote UE 702 is not within a coverage area of the NG RAN 706 (e.g., out of coverage), establishment of a 5G registration and / or a PDU session connection 716 between the remote UE 702 and the core network 708 via the NG RAN 706 can not occur; thus, this feature is not available to the remote UE 702. Figure 7 The establishment of a 5G registration and / or a PDU session connection 716 by the relay UE 704 is presented as optional in the middle.

[0104] After the establishment of a 5G registration and / or a PDU session connection 716 by the relay UE 704, the relay UE 704 can perform a relay UE PDU session establishment 720 with the core network 708.

[0105] According to some aspects disclosed herein, the remote UE 702 can execute or run instructions to cause one or more circuits to perform a UE-to-Network Relay UE discovery procedure 722. The UE-to-Network Relay UE discovery procedure 722 is described more fully herein in connection with Figure 8 and Figure 9 The UE-to-Network Relay UE discovery procedure 722 is described more fully herein in connection with Figure 10-13 An exemplary implementation of the UE-to-Network Relay UE 704 discovery procedure 722 is provided herein.

[0106] According to some aspects, at 724, the remote UE 702 and the relay UE 704 can establish a connection for a direct, one-to-one PC5 communication session. Further, the relay UE 704 can obtain security information from the core network 708, can check whether the remote UE 702 is authorized, and can authenticate the remote UE 702.

[0107] The relay UE 704 may optionally establish a new PDU session 726 for the relay node. The previous relay UE PDU session establishment 720 may not be associated with the remote UE 702. The new PDU session 726 may be associated with the remote UE 702.

[0108] The remote UE 702 and the relay UE 704 may obtain an IP address and prefix assignment 728 to associate with the remote UE 702. Thereafter, the relay UE 704 may issue a remote UE report 730 to the UPF 714. The remote UE report 730 may include, for example, a remote user ID and IP information of the remote UE 702. The remote UE 702 may issue user data and control signals 736 (collectively, traffic) to the relay UE 704, and the relay UE 704 may relay the traffic 738 to the UPF 714.

[0109] According to some aspects, a dedicated PDU session can be associated with one or more relay service codes. According to some aspects, the remote UE 702 can establish a PC5-S unicast link and obtain an IP address. The PC5-S unicast link access layer (AS) configuration can be managed using PC5-RRC. The remote UE 702 and the relay UE 704 can coordinate on the AS configuration. The relay UE 704 can configure the PC5 unicast link based on information from the NG RAN 706. Authentication / authorization of the remote UE 702 to access the relay feature of the relay UE 704 can be completed during the PC5 unicast link establishment. According to some aspects, the relay UE 704 can perform L3 relaying.

[0110] Communication systems such as 5G NR may support a direct discovery process in which a first UE may discover one or more second UEs that may be physically proximate to the first UE (and / or vice versa). The discovery of the first UE by the second UE (and vice versa) may be performed without guidance from the NG RAN and without guidance or use of features or functions of the core network. Direct discovery messages may be issued over a device-to-device interface, such as the NR PC5-D interface. According to some aspects described herein, direct discovery messages may be issued over the NR PC5-D interface between a first and a second UE. According to some examples, the first UE may be a remote UE (e.g., an out-of-coverage UE not connected to the network) and the second UE may be a relay UE (e.g., an in-coverage UE connected to the network). Once the remote UE discovers the relay UE, or the relay UE discovers the remote UE, the pair of UEs may be configured for one-to-one communication between them. The relay UE may relay user data and control signaling (collectively, traffic) of the remote UE to the core network via a RAN base station (e.g., eNB, gNB).

[0111] There may be two direct discovery models, referred to herein as Model A and Model B. The Model A discovery model involves a first UE sending an announcement discovery message on a PC5 channel. For example, in Model A direct discovery, a remote UE (e.g., a first UE) may announce its presence to one or more other UEs. The other UEs may monitor, for example, the PSCCH or PSSCH of a Model A announcement discovery message sent from the remote UE. The Model A discovery message may be a PC5 discovery message. The remote UE may be referred to as an announcement UE, while the other UEs may be referred to as monitoring UEs. Any one or more monitoring UEs may be relay UEs. A relay UE may be a UE with a network connection and may therefore serve as a relay node to a remote UE without a network connection (e.g., an out-of-coverage UE). The Model A discovery message (also referred to herein as an announcement discovery message) may be sent from an announcement UE (e.g., a remote UE) to a monitoring UE (e.g., one or more relay UEs) in a broadcast or multicast announcement discovery message. More specifically, the broadcast or multicast discovery message may include a media access control (MAC) header or subheader containing a parameter whose value indicates that the sender is a PC5-implemented UE. The PC5-D interface can interact with the MAC layer during PC5 discovery.

[0112] The Model B discovery model involves a first UE sending a request discovery message on a PC5 channel. For example, in Mode B direct discovery, a remote UE (e.g., a first UE) may seek to discover the presence of one or more other UEs. The other UEs may monitor the PSSCH for a Mode B discovery message, for example, sent from a remote UE. The Model B discovery message may be a PC5 discovery message. The remote UE may be referred to as a discoverer UE, and the other UEs may be referred to as discovered UEs. Any one or more discovered UEs may be relay UEs. The Model B discovery message (also referred to as a request discovery message) may be sent from a discoverer UE (e.g., a remote UE) to a discovered UE (e.g., one or more relay UEs) in a broadcast or multicast announcement discovery message. More specifically, the broadcast or multicast discovery message may include a media access control (MAC) header or subheader containing a parameter whose value indicates that the sender is a PC5-implemented UE. The response to the Model B discovery request may be unicast / broadcast.

[0113] According to aspects described herein, PC5 discovery messages (e.g., the announce discovery message of model A and the request discovery message of model B) can be carried in the PSSCH in the user plane. A separate physical discovery channel (e.g., the physical bypass discovery channel (PSDCH) in LTE) may not be required. In addition, no PHY layer modifications are required to implement the features and aspects described herein.

[0114] According to some aspects, for example, the content and / or security of the PC5 discovery message may be allocated in a 5G Direct Discovery Name Management Function (referred to herein as DDNMF). As known to those skilled in the art, the DDNMF may be a network node that may be used for open ProSe direct discovery to allocate and handle the mapping of ProSe application IDs and ProSe application codes used in ProSe direct discovery. The DDNMF may use ProSe-related subscriber data stored in a Home Subscriber Server (HSS) to authorize each discovery request. The DDNMF may also provide the necessary security material to the UE in order to protect the discovery messages sent over the air. According to some aspects, the DDNMF may be included in, for example, a Home Public Land Mobile Network (HPLMN) ProSe function, a Visited Public Land Mobile Network (VPLMN) ProSe function, or a Local Public Land Mobile Network (PLMN) ProSe function.

[0115] Figure 8 8 is a call flow diagram depicting a Model A discovery process 800 according to some aspects of the present disclosure. According to the Model A discovery process, a first UE 802 (UE-1, the announcing UE) sends an announce discovery message 812 to multiple neighboring UEs 804-810 (UE-2 to UE-5, the monitoring UEs). The announce discovery message 812 can be a PC5 discovery message. The first UE 802 can be a remote UE, which is outside the coverage of any base station and, therefore, outside the coverage of any network accessed via the base station. Any one or more of the multiple neighboring UEs 804-810 can be a relay UE, which is within the coverage of the base station (and, therefore, within the coverage of the network via the base station) and can relay user data and control signals (collectively referred to as traffic) between the remote UE and the network.

[0116] Figure 9is a call flow diagram depicting a Model B discovery process 900 according to some aspects of the present disclosure. According to the Model B discovery process, a first UE 902 (UE-1, the discovering UE) sends a request discovery message 912 to multiple neighboring UEs 904-910 (UE-2 to UE-5, the discovered UEs). The request discovery message 912 can be a PC5 discovery message. The first UE 802 can be a remote UE, which is outside the coverage of any base station and therefore outside the coverage of any network accessed via the base station. Any one or more of the multiple neighboring UEs 904-910 can be a relay UE, which is within the coverage of the base station (and therefore within the coverage of the network via the base station) and can relay user data and control signals (collectively referred to as traffic) between the remote UE and the network. Of the four neighboring UEs 904-910 that receive the request discovery message 912, two UEs (UE-2 904 and UE-3 906) respond to the request. UE-2 904 responds to the first response discovery message 914, and UE-3 906 responds to the second response discovery message 916. Each response discovery message may be a response PC5 discovery message.

[0117] Figure 10 1 is a diagram depicting a first pair of user plane protocol stacks (individually and collectively referred to as protocol stacks 1000) of a first UE 1002 and a second UE 1004, and an exemplary first data structure 1028 and an exemplary second data structure 1030, according to some aspects of the present disclosure. According to some aspects of the present disclosure, each of the first data structure 1028 and the second data structure 1030 may include a parameter indicating a discovery message. The discovery message may be a PC5 discovery message. The first UE 1002 may be configured to receive a discovery message from a user plane. Figure 3 Remote UE 318, Figure 6 Remote UE 602, Figure 7 Remote UE 702, Figure 8 UE-1 802 and / or Figure 9 The second UE 1004 may be composed of Figure 3 Relay UE 314, Figure 6 UE to network relay UE 604, Figure 7 UE to network relay UE 704, Figure 8 UE-2 804 and / or Figure 9 UE-2 802 is used as an example. Also according to some aspects of the present disclosure, the user plane protocol stack 1000 is depicted with a PC5-D interface 1006 therebetween.

[0118] exist Figure 10In the example of FIG, a first data structure 1028 is described as a packet data convergence protocol (PDCP) data packet data unit (PDU) formatted for a bypass (SL) data radio bearer (DRB) for multicast and broadcast messages (and for bypass SRB 0 messages), while a second data structure 1030 is described as a PDCP data PDU formatted for a bypass (SL) data radio bearer (DRB) for unicast messages. The common parameter between the first data structure 1028 and the second data structure 1030 is the service data unit (SDU) type 1032 parameter. To date, these data structures have not been used for PC5 discovery messages (e.g., for bypass discovery messages).

[0119] Figure 10 Also included is a table 1034 that provides a cross-reference between the SDU Type 1032 parameter and the bit values ​​1036 of the SDU Type Description 1038. The use of PDCP Data PDUs formatted for SL DRBs for multicast and broadcast messages, the use of PDCP Data PDUs formatted for SL DRBs for unicast messages, and their shared use of the SDU Type 1032 parameter field are non-limiting. Other data structures associated with the same or different data units transferred between the same or different protocol layers, with the same or different common parameters or no common parameters, are also within the scope of the present disclosure.

[0120] The user plane protocol stack 1000 of the first UE 1002 includes (at the lowest layer, L1, not shown) a physical layer 1008 (also referred to as a PHY layer). The user plane protocol stack 1000 of the first UE 1002 also includes a medium access control (MAC) layer 1010 on the physical layer 1008, a radio link control (RLC) layer 1012 on the MAC layer 1010, and a PDCP layer 1014 on the RLC layer 1012. The MAC layer 1010, the RLC layer 1012, and the PDCP layer 1014 may exist in a layer 2 L2 (not shown) (e.g., see FIG. Figure 5 The user plane protocol stack 1000 of the first UE 1002 also includes an SDAP layer 1015 on the PDCP layer 1014 and a PC5 discovery layer 1016 on the SDAP layer 1015. The PC5 discovery layer 1016 may reside in the non-access stratum (NAS) layer. The SDAP layer 1015 provides mapping between 5G core (5GC) quality of service (QoS) flows and data radio bearers and performs QoS flow ID marking in both downlink and uplink packets.

[0121] Similar to the first UE 1002, the user plane protocol stack 1000 of the second UE 1004 includes (at the lowest layer, L1, not shown) a physical layer 1018 (also referred to as a PHY layer). The user plane protocol stack 1000 of the second UE 1004 also includes a MAC layer 1020 on the physical layer 1018, an RLC layer 1022 on the MAC layer 1020, and a PDCP layer 1024 on the RLC layer 1022. The MAC layer 1020, the RLC layer 1022, and the PDCP layer 1024 may exist in a layer 2 L2 (not shown) (e.g., see FIG. Figure 5 The user plane protocol stack 1000 of the second UE 1004 further includes an SDAP layer 1025 on the PDCP layer 1024 and a PC5 discovery layer 1026 on the SDAP layer 1025.

[0122] The first data structure 1028 and the second data structure 1030, Figure 10 In the example of , the SL DRB formatted PDCP data PDUs for multicast and broadcast messages and the SL DRB formatted PDCP data PDUs for unicast messages, respectively, can be described as byte-length aligned bit strings (i.e., multiples of 8 bits, octets). The bit string is represented by the most significant bit, the most significant bit is the leftmost bit of the first row, and the least significant bit is the rightmost bit of the last row. More generally, the bit string is read from left to right and then read in the order in which the rows are read. The bit order of each parameter field within the first data structure 1028 and the second data structure 1030 is represented by the first and most significant bits in the leftmost bits and the last and least significant bits in the rightmost bits. In the example of the first data structure 1028, there are 3+M rows of octets, where M is a positive integer greater than 0. In the example of the second data structure 1030, there are N rows of octets, where N is a positive integer greater than or equal to 9. Other data structures, including the same or different number of bits in each row, and the same or different number of rows, are within the scope of the present disclosure.

[0123] The first data structure 1028 can be used, for example, for broadcasting and / or multicasting model A discovery messages and model B discovery messages. Each discovery message can be a PC5 discovery message. The first data structure 1028 can also be used, for example, for broadcasting a response discovery message in response to a model B request discovery message. The second data structure 1030 can be used, for example, for unicasting a response discovery message in response to a model B broadcast and / or multicast request discovery message.

[0124] Both the first data structure 1028 and the second data structure 1030 include a first parameter that may indicate a discovery message. The discovery message may be a PC5 discovery message. Examples of the first data structure 1028 and the second data structure 1030 are PDCP data PDUs. The first parameter indicating a discovery message may be a PDCP service data unit (SDU) type 1032 parameter. The SDU type 1032 parameter is included in both examples of the first data structure 1028 and the second data structure 1030. The PDCP SDU type may be a Layer 3 PDU type. The type of the SDU may be useful because a PDCP entity may process an SDU differently based on its SDU type 1032.

[0125] According to aspects described herein, indicating an SDU type 1032 of a discovery message may be implemented by using an available bit value 1036 associated with the SDU type 1032. The discovery message 1040 may be a PC5 discovery message 1040. For example, the bit value 1036 may be available if the bit value is reserved for future use. For example, according to some specifications, the bit value 1036 "000" corresponds to an IPSDU type, the bit value 1036 "001" corresponds to a non-IP SDU type, and bit values ​​in the range "010"-"111" are reserved for future use. According to some aspects of the present disclosure, the previously reserved bit value 1036 "010" may be used to indicate a PDCP data PDU carrying that value, such as the SDU type 1032, indicating that the discovery message associated with the PDCP data SDU is a PC5 discovery message 1040. According Figure 10In an example, a SL DRB formatted PDCP data PDU for multicast and broadcast messages transmitted over the user plane (e.g., according to the first data structure 1028), which has a value of "010" in the SDU type 1032 field, can be used to indicate the transmission of a PC5 discovery message (e.g., an announcement and / or request discovery message) from a remote UE (e.g., the first UE 1002) to a neighboring UE (individually and collectively represented by the second UE 1002). In addition, a SL DRB formatted PDCP data PDU for unicast messages transmitted over the user plane (e.g., according to the second data structure 1030), which has a value of "010" in the SDU type 1032 field, can be used to indicate that a response PC5-discovery message 1040 is being sent from a relay UE (e.g., the second UE 1004) to a requesting remote UE (e.g., the first UE 1002). The SDU type 1032 field can be populated with other values. For example, a value of 011 can indicate that the discovery message is a PC5 discovery message of model A type 1041. A value of 100 may indicate that the discovery message is a PC5 discovery message of Model B type 1042. A value of 101 may indicate that the discovery message is a PC5 discovery message of Model B type and corresponds to a Model B query message 1043, while a value of 110 may indicate that the discovery message is a PC5 discovery message of Model B type and corresponds to a Model B response message 1044. The three-bit values ​​of the SDU Type parameter used in the first data structure 1028 and / or the second data structure 1030 to indicate the presence of PC5 discovery message 1040, PC5 discovery Model A type 1041, PC5 discovery Model B type 1042, PC5 discovery Model B type corresponding to Model B query message 1043, and / or PC5 discovery Model B type corresponding to Model B response message 1044 are exemplary and non-limiting. According to some aspects, any or all of the information conveyed by the SDU Type value may additionally or alternatively be conveyed in a header associated with a PDCP data PDU from a higher protocol layer (compared to the PDCP protocol layer). Thus, some bit values ​​1036 and SDU type descriptions 1038 may be optional, for example, using a bit value of 101 to indicate a PC5 discovery Model B type corresponding to a Model B query message 1043, and / or using a bit value of 110 to indicate a PC5 discovery Model B type corresponding to a Model B response message 1044. A higher protocol layer may be, for example, the PC5 discovery protocol layer 1026. The same or different parameters having the same or different numbers of bits and the same or different values ​​are also within the scope of the present disclosure. In addition, the use of a PDCP data PDU to carry an indication of the PC5 discovery message 1040 is exemplary and non-limiting; other data PDUs, SDUs, or other forms of bits are also within the scope of the present disclosure. For example, discovery messages including any discovery message mentioned herein may be sent over the user plane in a physical bypass shared channel (PSSCH).According to one example, discovery messages carried in the PSSCH may be specified in 3GPP Release 16 New Radio (NR) V2X. No separate discovery physical channel (e.g., Physical Bypass Discovery Channel (PSDCH) in LTE) is required.

[0126] Additional parameters represented in the first data structure 1028 include a reserved (R) bit, a PDCP sequence number (SN) (12 bits represented in octets 1-2), and data (in the remaining octets). The R bit may be reserved for future use and may be ignored by the receiver. The PCCP SN bit may be configured by upper layers to be 12 or 18 bits in length. Figure 10 In the example shown, the PDCP SN has 12 bits. The 12-bit length can indicate an unacknowledged mode (UM) data radio bearer (DRB), an acknowledged mode (AM) DRB, and an SRB (including a bypass DRB and a bypass SRB). The 18-bit length, not shown, can indicate a UM DRB, an AM DRB (including a bypass DRB for unicast). According to some aspects, for NR bypass communications for multicast and broadcast, only the 12-bit PDCP SN length is used for the bypass DRB. No reference numerals are provided for the R parameter field, the PDCP SN parameter field, and the data field to avoid cluttering the figures.

[0127] Parameters represented in the second data structure 1030 include a PDCP service data unit (SDU) type 1032. SDU type 1032 has been described above and will not be repeated for the sake of brevity. Additional parameters represented in the second data structure 1030 include a PDCP sequence number (SN) (12 bits represented in octets 1-2). The PDCP SN bits can be configured by upper layers to be 12 or 18 bits in length. The description of the PDCP SN provided above in conjunction with the first data structure 1028 applies to the PDCP SN of the second data structure 1030.

[0128] The additional parameters represented in the second data structure 1030 also include a D / C parameter, a parameter called K NRP-sess The key of the ID and the message authentication code for integrity (MAC-I) parameter. The D / C parameter can indicate whether the corresponding PDCP PDU is a PDCP data PDU or a PDCP control PDU. TS 33.536 specifies the K NRP-sess For SL DRBs that do not require integrity and encryption protection, the UE may include K in the PDCP data PDU header. NRP-sessThe ID value is set to "0". The MAC-I field carries the message authentication code. For bypass SRB1, SRB2 and SRB3, the MAC-I field will only appear when bypass SRB1, SRB2 and SRB3 are configured with integrity protection. D / C parameter field, PDCP SN parameter field, K NRP-sess The ID parameter field, the MAC-I parameter field, and the data field are not provided with reference numerals to avoid cluttering the drawing.

[0129] Regarding priority handling, a relay UE (such as the second UE 1004) may need to prioritize message transmissions on the PC5 interface. According to aspects described herein, there may be at least two examples of ways of handling message prioritization (e.g., the priority of a PC5-D message compared to a PC5-S message). In one example, if a relay node can transmit more than one message, then as described herein, a PC5 discovery message 1040 transmitted on a physical bypass shared channel (PSSCH) may have a lower priority than other messages transmitted on a physical bypass control channel (PSCCH). According to one example, a PC5 discovery message transmitted on the PSSCH has the lowest priority among messages transmitted on the PSCCH. According to another example, a PC5 discovery message transmitted on a bypass transport channel (STCH) has a lower priority than other messages transmitted on a physical bypass control channel (PSCCH). According to another example, messages in a bypass traffic channel (STCH) may be prioritized in at least one of two alternatives. According to a first alternative, prioritization may be performed based on the priority of the logical channel (LCH) on which the discovery message is transmitted, for example as configured in the RRC. According to a second alternative, the priority of the discovery message may be the highest priority among messages transmitted on the STCH. In some examples, the priority of the discovery message may be fixed to the highest priority among messages transmitted on the STCH. In other words, the priority of the PC5 discovery message is at least one of the following: based on the logical channel (LCH) priority of the logical channel on which the discovery message is transmitted, or fixed to the highest priority among messages transmitted on the STCH. In all examples and alternatives, the discovery message may be a PC5 discovery message.

[0130] Figure 11 is a diagram depicting a second pair of user plane protocol stacks (individually and collectively referred to as protocol stacks 1100) of a first UE 1102 and a second UE 1104 according to some aspects of the present disclosure, and an exemplary third data structure 1128. According to some aspects of the present disclosure, the third data structure 1128 may include parameters indicating a discovery message. The first UE 1102 may be Figure 3 Remote UE 318, Figure 6 Remote UE 602, Figure 7Remote UE 702, Figure 8 UE-1 802 and / or Figure 9 The second UE 1104 can be represented by UE-1 902. Figure 3 Relay UE 314, Figure 6 UE to network relay UE 604, Figure 7 UE to network relay UE 704, Figure 8 UE-2 804 and / or Figure 9 UE-2 904 is used as an example. Also according to some aspects of the present disclosure, the user plane protocol stack 1100 is depicted with a PC5-D interface 1106 therebetween.

[0131] exist Figure 11 In the example, the third data structure 1128 is depicted as a MAC subheader with an 8-bit LCID field. The MAC subheader is part of the MAC PDU. The MAC subheader can be a byte-aligned bit string (e.g., a multiple of 8 bits, octets). Each MAC subheader can be placed directly before the corresponding MAC SDU, MAC CE, or padding. The MAC PDU is a byte-aligned bit string (i.e., a multiple of 8 bits). In the third data structure 1128, the bit string is represented, where the most significant bit is the leftmost bit of the first row of the third data structure 1128, and the least significant bit is the rightmost bit of the last row of the third data structure 1128. More generally, the bit string is read from left to right and then in the order in which the rows are read. The bit order of each parameter field within the MAC PDU is represented by the first and most significant bit in the leftmost bit and the last and least significant bit in the rightmost bit. The MAC SDU is a byte-aligned bit string (i.e., a multiple of 8 bits). Starting from the first bit, the MAC SDU is included in the MAC PDU. The MAC CE is a byte-length aligned bit string (ie, a multiple of 8 bits). To date, the third data structure 1128 has not been used for PC5 discovery messages (eg, for bypass discovery messages).

[0132] The user plane protocol stack 1100 of the first UE 1102 includes (at the lowest layer, L1, not shown) a physical layer 1108 (also referred to as a PHY layer). The user plane protocol stack 1100 of the first UE 1102 also includes a medium access control (MAC) layer 1110 on the physical layer 1108, a radio link control (RLC) layer 1112 on the MAC layer 1110, and a PDCP layer 1114 on the RLC layer 1112. The MAC layer 1110, the RLC layer 1112, and the PDCP layer 1114 may exist in a layer 2 L2 (not shown) (e.g., see FIG. Figure 5The user plane protocol stack 1100 of the first UE 1102 also includes an SDAP layer 1115 on the PDCP layer 1114 and a PC5 discovery layer 1116 on the SDAP layer 1115. The PC5 discovery layer 1016 may be present in the non-access stratum (NAS) layer. The SDAP layer 1015 provides mapping between 5G core (5GC) quality of service (QoS) flows and data radio bearers and performs QoS flow ID marking in downlink and uplink packets. The SDAP layer 1115 and the PC5 discovery layer 1116 may be present in layer 3 L3 (not shown) (see, for example, FIG. Figure 5 L3 509).

[0133] Similar to the first UE 1102, the user plane protocol stack 1100 of the second UE 1104 includes (at the lowest layer, L1, not shown) a physical layer 1118 (also referred to as a PHY layer). The user plane protocol stack 1100 of the second UE 1104 also includes a medium access control (MAC) layer 1120 on the physical layer 1118, a radio link control (RLC) layer 1122 on the MAC layer 1120, and a PDCP layer 1124 on the RLC layer 1122. The MAC layer 1120, the RLC layer 1122, and the PDCP layer 1124 may exist in a layer 2 L2 (not shown) (e.g., see FIG. Figure 5 The user plane protocol stack 1100 of the second UE 1104 further includes an SDAP layer 1125 on the PDCP layer 1124 and a PC5 discovery layer 1126 on the SDAP layer 1125.

[0134] As described above, the third data structure 1128 (e.g., a MAC subheader) can be described as a bit string that is byte-aligned in length (i.e., a multiple of 8 bits, an octet). The bit string is represented with the most significant bit being the leftmost bit of the first row and the least significant bit being the rightmost bit of the last row. More generally, the bit string is read from left to right and then in the order in which the rows are read. The bit order of each parameter field in the third data structure 1128 is represented with the first and most significant bit being the leftmost bit and the last and least significant bit being the rightmost bit. In the example of the third data structure 1128, there are 2 rows of octets of bits, corresponding to a total of 16 bits. Other data structures, including the same or different number of bits in the same or different number of bits per row, and the same or different number of rows, are within the scope of the present disclosure.

[0135] The third data structure 1128 can be used, for example, to convey model A type discovery messages (e.g., advertise discovery messages) and model B type discovery messages (e.g., request discovery messages). The third data structure 1128 includes a logical channel identifier (LCID) field 1130. The LCID field 1130 can be used to indicate the identifier of the logical channel to which the MAC subheader applies. In the example described herein, the LCID field 1130 can be used to indicate that the discovery message can be a PC5 discovery message 1138. In the exemplary third data structure 1128, the length of the LCID field is 6 bits. According to aspects described herein, index number 1134 can indicate a PC5 discovery message 1138. Using index number 1134 for this purpose can be achieved by using an available index number 1134 of the MAC subheader (e.g., of the third data structure 1128). For example, if index number 1134 is reserved for future use, then index number 1134 may be available. For example, according to some specifications, index numbers "4"-"19" correspond to the identification of logical channels, while index numbers "20"-"61" are reserved for future use. According to some aspects of the present disclosure, the previously reserved index number 1134 "57" can be used to indicate a logical channel including Figure 11 The MAC PDU with index number 1134 "57" of the MAC subheader (e.g., the third data structure 1128) indicates a PC5 discovery message 1138. Using a different reserved index number, such as "21" is also within the scope of the present disclosure. Figure 11 For example, transmission of a MAC PDU formatted with a MAC subheader having a value of "57" in the LCID field 1130 (e.g., formatted with the third data structure 1128) over the user plane may be used to indicate transmission of a PC5 discovery message 1138 (e.g., an announcement and / or request discovery message) from a remote UE (e.g., the first UE 1102) to a neighboring UE (individually and collectively represented by the second UE 1104). Additionally, transmission of a MAC PDU formatted with a MAC subheader having a value of "57" in the LCID field 1130 (e.g., formatted with the third data structure 1128) over the user plane may be used to indicate that a PC5-D discovery response message is being sent from a relay UE (e.g., the second UE 1104) to a requesting remote UE (e.g., the first UE 1102).

[0136] The LCID 1130 field can be populated with other index numbers 1134. For example, index value 58 can indicate that the discovery message is a PC5 discovery message of Model A type 1139. Index value 59 can indicate that the discovery message is a PC5 discovery message of Model B type 1140. Index value 60 can indicate that the discovery message is a PC5 discovery message of Model B type and corresponds to a Model B query message 1141, while index value 57 can indicate that the discovery message is a PC5 discovery message of Model B type and corresponds to a Model B response message 1142. The illustrated index values for the LCID 1130 parameter in the third data structure 1128 indicate the presence of a PC5 discovery message 1138, a PC5 discovery message of Model A type 1139, a PC5 discovery message of Model B type 1140, a PC5 discovery message of Model B type corresponding to a Model B query message 1141, and / or a PC5 discovery message of Model B type corresponding to a Model B response message 1142, which are exemplary and not limiting. According to some aspects, any or all of the information conveyed by the value of the SDU type can additionally or alternatively be conveyed in a header associated with a PDCP data PDU from a higher protocol layer (as compared to the PDCP protocol layer). Thus, some of the index number values 1134 and LCID values descriptions 1136 can be optional, e.g., using index value 60 to represent a PC5 discovery message of Model B type corresponding to a Model B query message 1141, and / or using index value 61 to represent a PC5 discovery message of Model B type corresponding to a Model B response message 1142. The higher protocol layer can be, for example, a PC5 discovery protocol layer 1126. The six-bit LCID parameter and the use of the illustrated index numbers to represent various PC5 discovery message types / configurations are exemplary and not limiting. The same or different parameters with the same or different values and / or bit numbers are within the scope of the present disclosure. Moreover, the use of a MAC subheader of a MAC PDU to carry an indication of a PC5 discovery message is exemplary and not limiting; other data PDUs, SDUs, headers, and / or subheaders or other forms of bits are also within the scope of the present disclosure.

[0137] Additional parameters represented in the third data structure 1128 include a reserved (R) bit, an F bit, and an L field (representing 8 bits in octet 2). The R bit can be reserved for future use and can be ignored by the receiver. The F bit represents the format field, which indicates the size of the length (L) field. According to some aspects, each MAC subheader has an F field, except for the subheader corresponding to the SL-SCH subheader or padding. The size of the F field is 1 bit. A value of 0 indicates 8 bits of the length (L) field. A value of 1 indicates 16 bits of the L field. The L field is a length field that indicates the length of the corresponding MAC SDU in bytes. According to some aspects, each MAC subheader has an L field, except for the subheader corresponding to the SL-SCH subheader or padding. The size of the L field is indicated by the F field. No reference numerals are provided for the R parameter field, the F parameter field, and the L parameter field to avoid cluttering the drawings.

[0138] Figure 11 Also included is a table 1132 that provides a cross-reference between an index number 1134 and an LCID value 1136 associated with an LCID field 1130 present in the third data structure 1128 (e.g., a MAC subheader). The unique index number 1134 and LCID value 1136 are depicted in the seventh row of table 1132; that is, the LCID value 1136 that may correspond to a PC5 discovery message 1138 may be indexed to the index number "61." Thus, transmission of a MAC PDU with a MAC subheader having an index number "61" in the LCID field 1130 over the user plane may be used to indicate that a PC5 discovery message (e.g., an announcement and / or request discovery message) is being sent from a remote UE to a neighboring UE. Furthermore, transmission of a MAC PDU with a MAC subheader having an index number "61" in the LCID field 1130 over the user plane may be used to indicate that a response PC5 discovery message 1138 is being sent from a relay UE to a requesting remote UE. The index number "61" indicating the LCID value 1136 of the PC5 discovery message 1138 in the third data structure 1128 is exemplary and non-limiting. Other values ​​for the same or other parameters in the exemplary third data structure 1128 or other values ​​for any other MAC subheader are within the scope of the present disclosure.

[0139] Priority processing and use of messages configured using the third data structure 1128 Figure 10 The first data structure 1028 and Figure 10 The priority processing of the messages configured by the second data structure 1030 is the same or similar; therefore, for the sake of brevity, the description of the priority processing is omitted. However, when compared with the use of Figure 10 The first data structure 1028 and Figure 10 The second data structure 1030 configures the priority of the message when compared to the use Figure 11The priority handling of messages configured by the third data structure 1128 can provide more flexibility in configuring the priority of discovery messages. For example, a discovery message can be associated with any of the reserved index numbers (e.g., 20-61). The priority of index number 21 can be configured to be higher than the priority of index 61; thus, when more than one LCID value is used to indicate a PC5 discovery message, the use of Figure 11 The third data structure can enable more priority level choices.

[0140] Figure 12 is a diagram depicting a third pair of user plane protocol stacks (individually and collectively referred to as protocol stacks 1200) of a first UE 1202 and a second UE 1204 and an exemplary first data structure 1228 (e.g., PDCP data PDU) and second data structure 1234 (e.g., MAC subheader) of a MAC PDU 1232, in accordance with some aspects of the present disclosure. The first data structure 1228 and the second data structure 1234 can include parameters indicating a discovery message, in accordance with some aspects of the present disclosure. The discovery message can be a PC5 discovery message. The first UE 1202 can be exemplified by Figure 3 the remote UE 318 of FIG. 1, Figure 6 the remote UE 602 of FIG. 6, Figure 7 the remote UE 702 of FIG. 7, Figure 8 the UE-1 802 of FIG. 8, and / or Figure 9 the UE-1 902 of FIG. 9. The second UE 1204 can be exemplified by Figure 3 the remote UE 314 of FIG. 1, Figure 6 the UE-to-Network Relay UE 604 of FIG. 6, Figure 7 the UE-to-Network Relay UE 704 of FIG. 7, Figure 8 the UE-2 804 of FIG. 8, and / or Figure 9 the UE-2 902 of FIG. 9. Also in accordance with some aspects of the present disclosure, the user plane protocol stacks 1000 are depicted with a PC5-D interface 1006 therebetween.

[0141] The user plane protocol stack 1200 of the first UE 1202 includes (at the lowest layer, LI, not shown) a physical layer 1208 (also referred to as a PHY layer). The user plane protocol stack 1200 of the first UE 1202 also includes a medium access control (MAC) layer 1210 over the physical layer 1208, a radio link control (RLC) layer 1212 over the MAC layer 1210, and a PDCP layer 1214 over the RLC layer 1212. The MAC layer 1210, the RLC layer 1212, and the PDCP layer 1214 can exist in a layer 2, L2, not shown (e.g., see FIG. 1). Figure 5The user plane protocol stack 1200 of the first UE 1202 also includes an SDAP layer 1215 on the PDCP layer 1214 and a PC5 discovery layer 1216 on the SDAP layer 1215. The PC5 discovery layer 1216 may reside in the non-access stratum (NAS) layer. The SDAP layer 1215 provides mapping between 5G core (5GC) quality of service (QoS) flows and data radio bearers and performs QoS flow ID marking in downlink and uplink packets. The PC5 discovery layer 1216 may be considered an application layer, for example.

[0142] Similar to the first UE 1202, the user plane protocol stack 1200 of the second UE 1204 includes (at the lowest layer, L1, not shown) a physical layer 1218 (also referred to as a PHY layer). The user plane protocol stack 1200 of the second UE 1204 also includes a MAC layer 1220 on the physical layer 1218, an RLC layer 1222 on the MAC layer 1220, and a PDCP layer 1224 on the RLC layer 1222. The MAC layer 1220, the RLC layer 1222, and the PDCP layer 1224 may exist in a layer 2 L2 (not shown) (e.g., see FIG. Figure 5 The user plane protocol stack 1200 of the second UE 1204 further includes an SDAP layer 1225 on the PDCP layer 1224 and a PC5 discovery layer 1226 on the SDAP layer 1225.

[0143] Figure 12 Also includes Figure 10 and Figure 11 The descriptions of Table 1034 and Table 1132 are respectively the same as Figure 10 and Figure 11 The description of the protocol stack 1200 of the first UE 1202 and the protocol stack 1200 of the second UE 1204 are the same or substantially similar and will not be repeated for the sake of brevity. Figure 10 The protocol stack 1000 and Figure 11 The descriptions provided for the protocol stack 1100 are the same or substantially similar and will not be repeated for the sake of brevity.

[0144] Figure 12 The diagram depicts a first data structure 1228 (eg, a PDCP data PDU) and a second data structure 1234 (eg, a MAC subheader) of a MAC PDU 1232. Figure 12 The first data structure 1228 is Figure 10 The first PDCP data PDU (ie, the first data structure 1028) or Figure 10 The second PDCP data PDU (ie, the second data structure 1030) is the same as or similar to the second PDCP data PDU. Figure 11 The MAC subheader of the MAC PDU (i.e., the third data structure 1128) is the same or similar to the first data structure 1028, the second data structure 1030, and the third data structure 1128. For the sake of brevity, the description of the first data structure 1028, the second data structure 1030, and the third data structure 1128 will not be repeated.

[0145] According to one aspect of the protocol stack 1200, Figure 12 the first UE 1202 can broadcast and / or groupcast a Model A type of discovery message (e.g., an announce discovery message) and / or a Model B type of discovery message (e.g., a request discovery message) using a first data structure 1228 (e.g., a PDCP data PDU) having a data structure including a first parameter field 1230 having a value indicating the discovery message. The discovery message can be a PC5 discovery message. According to such an aspect, the data structure of the first data structure 1228 can correspond to a PDCP data PDU formatted for groupcast and broadcast SL DBR, such as the first data structure 1028 of Figure 10 According to such an aspect, the first parameter field 1230 can be an SDU type Figure 10 (1032) parameter field. According to such an aspect, the first parameter field 1230 can have a value “010” corresponding to the SDU type description 1038 of the PC5 discovery message 1040.

[0146] According to another aspect of the protocol stack 1200, Figure 12 the first UE 1202 can broadcast and / or groupcast a Model A type of discovery message (e.g., an announce discovery message) and / or a Model B type of discovery message (e.g., a request discovery message) using a MAC PDU 1232 having a data structure including a second parameter field 1236 having a value indicating the discovery message. The discovery message can be a PC5 discovery message. According to such an aspect, the second data structure 1234 (e.g., a MAC subheader) of the MAC PDU 1232 can correspond to the third data structure 1128 of Figure 11 According to such an aspect, the second parameter field 1236 can be an LCID field Figure 11 (1130) of the third data structure 1128. According to such an aspect, the second parameter field 1236 has an index value “57” corresponding to the LCID value 1136 of the “PC5 discovery message” 1138.

[0147] According to another aspect of the protocol stack 1200, Figure 12In another aspect of the protocol stack 1200, the first UE 1202 can broadcast and / or multicast a Model A type discovery message (e.g., an announce discovery message) and / or a Model B type discovery message (e.g., a request discovery message) using both the first data structure 1228 (e.g., a PDCP data PDU) and the MAC PDU 1232. The discovery message can be a PC5 discovery message.

[0148] according to Figure 12 In another aspect of the protocol stack 1200, the second 1204 can respond to a broadcast and / or multicast model A type discovery message and / or a broadcast and / or multicast model B type discovery message using a first data structure 1228 (e.g., a PDCP data PDU) having a data structure including a first field indicating a discovery message. The discovery message can be a PC5 discovery message. According to such an aspect, the data structure can correspond to a PDCP data PDU formatted for an SL DRB for a unicast message, such as Figure 10 The second data structure 1030.

[0149] use Figure 12 Priority processing and use of messages configured in the first data structure 1228 (e.g., PDCP data PDU) and / or MAC PDU 1232 Figure 10 The first data structure 1028, Figure 10 The second data structure 1030 and / or Figure 11 The priority processing of the messages configured by the third data structure 1128 is the same or similar; therefore, for the sake of simplicity, the priority processing of the messages configured by the third data structure 1128 is omitted. Figure 12 Description of the priority handling of the associated discovery messages. Figure 12 An example of configuring the priority handling of messages is provided using Figure 10 and Figure 11 The example implementation shows the benefits of priority processing.

[0150] and Figure 10 、 Figure 11 and Figure 12 The message security aspects of the PC5 discovery message associated with the example of indicates that there may be no ciphering and integrity protection in the PDCP layer. Figure 10 、 Figure 11 and Figure 12 The second UE 1004, 1104 and 1204) may not implement encryption and integrity protection respectively, so that the relay UE can at least complete the communication with the remote UE (such as Figure 10 、 11 and an initial connection of the first UE 1002, 1102, and 1202). For example, security protection may be provided via the DDNMF (eg, in the application layer).

[0151] Figure 13 is an exemplary third data structure 1128 (from which) depicts a fourth pair of user plane protocol stacks (individually and collectively referred to as protocol stacks 1300) for a first UE 1302 and a second UE 1304 according to some aspects of the present disclosure and which may carry an indication of a discovery message. Figure 11 According to some aspects of the present disclosure, the third data structure 1128 may carry an indication of a discovery message. The discovery message may be a PC5 discovery message. The first UE 1302 may be Figure 3 Remote UE 318, Figure 6 remote UE 602, Figure 7 Remote UE 702, Figure 8 UE-1 802 and / or Figure 9 The second UE 1304 can be represented by Figure 3 Relay UE 314, Figure 6 UE to network relay UE 604, Figure 7 UE to network relay UE 704, Figure 8 UE-2 804 and / or Figure 9 UE-2 904 is used as an example. Also according to some aspects of the present disclosure, the user plane protocol stack 1300 is depicted with a PC5-D interface 1306 therebetween.

[0152] exist Figure 13 In the example of FIG. 1 , the third data structure 1128 is described as a MAC subheader having an 8-bit LCID field and in combination with Figure 11 The third data structure 1128 is the same as described above. Therefore, for the sake of brevity, the description of the third data structure 1128 is omitted.

[0153] The user plane protocol stack 1300 of the first UE 1302 includes (at the lowest layer, L1, not shown) a physical layer 1308 (also referred to as a PHY layer). The user plane protocol stack 1300 of the first UE 1302 also includes a medium access control (MAC) layer 1310 on the physical layer 1308. The MAC layer 1310 may reside in layer 2 L2 (not shown) (e.g., see FIG. Figure 5 The user plane protocol stack 1300 of the first UE 1302 also includes a PC5 discovery layer 1316 on the MAC layer 1310. The PC5 discovery layer 1316 may exist in layer 3 L3 (see, for example, Figure 5 L3 509).

[0154] Similar to the first UE 1302, the user plane protocol stack 1300 of the second UE 1304 includes (at the lowest layer, L1, not shown) a physical layer 1318 (also referred to as a PHY layer). The user plane protocol stack 1300 of the second UE 1304 also includes a medium access control (MAC) layer 1320 on the physical layer 1318. The MAC layer 1320 may exist in layer 2 L2 (not shown) (e.g., see FIG. Figure 5 The user plane protocol stack 1300 of the second UE 1304 further includes a PC5 discovery layer 1326 on the MAC layer 1320.

[0155] Figure 10 The first data structure 1028 and Figure 10 The second data structure 1030 is not applicable to Figure 13 , since those data structures depend on PDCP PDUs, and Figure 13 The user plane protocol stack 1300 does not include the RLC or PDCP layer. Figure 13 The third data structure 1128 of the example can be used, for example, to transmit a discovery message of the model A type and / or a discovery message of the model B type. The discovery message can be a PC5 discovery message. The third data structure 1128 includes a logical channel identifier (LCID) field 1130. The LCID field 1130, the table 1132, the index number 1134, the LCID value 1136, and the PC5 discovery message 1138 corresponding to the index number "57" are all as shown in FIG. Figure 11 described; for the sake of brevity, their description will be omitted.

[0156] In some aspects of the present disclosure, a remote UE (e.g., Figure 3 Remote UE 318, Figure 6 remote UE 602, Figure 7 Remote UE 702, Figure 8 UE-1 802, Figure 9 UE-1 902 and Figure 10-13 The first UE 1002, 1102, 1202, 1302) can use the data structure indicating the discovery message to broadcast and / or multicast the discovery message of model A type (e.g., announcement discovery message) and / or the discovery message of model B type (e.g., request discovery message). The discovery message can be a PC5 discovery message. In some aspects of the present disclosure, the relay UE (e.g., Figure 3 Relay UE 314, Figure 6 UE to network relay UE 604, Figure 7 UE to network relay UE 704, Figure 8 UE-2 804, Figure 9UE-2 802 and Figure 10-13 The second UE 1004, 1104, 1204, 1304) can use the data structure indicative of the discovery message to respond to the broadcast and / or multicast of the PC5 discovery message (e.g., the request discovery message).

[0157] exist Figure 13 The priority processing of messages configured using the third data structure 1128 is performed using Figure 11 The priority processing of the messages configured by the third data structure 1128 is the same or similar; therefore, for the sake of brevity, the description of the priority processing is omitted. Figure 13 An example of configuring the priority handling of messages is provided using Figure 11 The example implementation shows the benefits of priority processing.

[0158] exist Figure 10 、 Figure 11 、 Figure 12 and Figure 13 The foregoing examples shown in and described in the related text apply to both Layer 2 (L2) relays and Layer 3 (L3) relays.

[0159] Figure 14 1 is a block diagram illustrating an example of a hardware implementation of a remote UE and / or relay UE configured to employ a processing system 1414 for PC5 communications (hereinafter referred to as UE 1400) according to some aspects of the present disclosure. For example, UE 1400 may be any UE or wireless communication device configured for PC5 communications, such as Figure 1-Figure 3 and Figure 6-Figure 13 Any one or more of the following.

[0160] According to various aspects of the present disclosure, an element or any portion of an element or any combination of elements may be implemented using a processing system 1414 that includes one or more processors, such as the processor 1404. Examples of the processor 1404 include a microprocessor, a microcontroller, a digital signal processor (DSP), a field programmable gate array (FPGA), a programmable logic device (PLD), a state machine, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described in the present disclosure. In various examples, the UE 1400 may be configured to perform any one or more of the functions described herein. That is, the processor 1404 used in the UE 1400 may be used to implement, for example, Figure 6-Figure 9 、 Figure 15 and / or Figure 16 Any one or more methods or processes described and illustrated in.

[0161] In this example, the processing system 1414 can be implemented with a bus architecture, as represented generally by the bus 1402. The bus 1402 can include any number of interconnecting buses and bridges depending on the specific application of the processing system 1414 and the overall design constraints. The bus 1402 communicatively couples various circuitry including one or more processors (generally represented by the processor 1404), memory 1405, and computer-readable media (generally represented by the computer-readable media 1406). The bus 1402 can also link various other circuitry, such as a timing source, peripherals, voltage regulators, and power management circuitry, which are well known in the art, and therefore, not further described.

[0162] The bus interface 1408 provides an interface between the bus 1402 and the transceiver 1410. The transceiver 1410 can be, for example, a wireless transceiver. The transceiver 1410 provides a means for communicating with various other apparatus over a transmission medium (e.g., an air interface). The transceiver 1410 can further be coupled to one or more antennas / antenna arrays / antenna modules 1420. The bus interface 1408 also provides an interface between the bus 1402 and a user interface 1412 (e.g., keypad, display, touch screen, speaker, microphone, control buttons, etc.). Of course, such a user interface 1412 is optional and can be omitted in some examples. In addition, the bus interface 1408 also provides an interface between the bus 1402 and a power supply 1428 and between the bus 1402 and an application processor 1430, which can be separate from the processor 1404 and / or modem (not shown) of the UE 1400 or processing system 1414.

[0163] One or more processors, such as the processor 1404, can be responsible for managing the bus 1402 and general processing, including the execution of software stored on the computer-readable medium 1406. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software can reside on the computer-readable medium 1406. The software, when executed by the processor 1404, causes the processing system 1414 to perform various processes and functions described herein for any particular apparatus.

[0164] Computer-readable medium 1406 may be a non-transitory computer-readable medium and may be referred to as a computer-readable storage medium or a non-transitory computer-readable medium. Non-transitory computer-readable medium may store computer-executable code (e.g., processor-executable code). Computer-executable code may include code for causing a computer (e.g., a processor) to implement one or more functions described herein. As an example, non-transitory computer-readable media include magnetic storage devices (e.g., hard disks, floppy disks, magnetic strips), optical disks (e.g., compact disks (CDs) or digital versatile disks (DVDs)), smart cards, flash memory devices (e.g., cards, sticks, or key drives), random access memory (RAM), read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), registers, removable disks, and any other suitable medium for storing software and / or instructions that are accessible and readable by a computer. Computer-readable medium 1406 may reside in processing system 1414, external to processing system 1414, or distributed across multiple entities including processing system 1414. Computer-readable medium 1406 may be included in a computer program product or article of manufacture. For example, a computer program product or article of manufacture may include the computer-readable medium in packaging materials. In some examples, computer-readable medium 1406 may be part of memory 1405. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure based on the specific application and the overall design constraints imposed on the entire system. Computer-readable medium 1406 and / or memory 1405 may also be used to store data manipulated by processor 1404 when executing software.

[0165] In some aspects of the disclosure, the processor 1404 can include communication and processing circuitry 1441 configured for various functions, including, for example, communicating with other UEs (e.g., over a PC5 interface), base stations (e.g., over a UU interface), network cores (e.g., via a 5G core network of a base station), or any other entity (e.g., a local infrastructure or an entity in communication with the UE 1400 via the Internet, such as a network provider). In some examples, the communication and processing circuitry 1441 can include one or more hardware components that provide physical structure to execute processes related to wireless communication (e.g., signal reception and / or signal transmission and signal processing (e.g., processing received signals and / or processing signals for transmission, such as transmitting a discovery message over a user plane using a first data structure including a first parameter indicating the discovery message, and / or transmitting a discovery message including an indication that the message is a discovery message for a service over a user plane using a determined sidelink resource)). Further, the communication and processing circuitry 1441 can be configured to receive and process uplink traffic and uplink control messages (e.g., similar to uplink traffic 116 and uplink control 118 of Figure 1 ), and process and transmit downlink traffic and downlink control messages (e.g., similar to downlink traffic 112 and downlink control 114), and / or receive, transmit, and process sidelink messages (e.g., similar to sidelink 124 of Figure 1 ) via the antenna / antenna array / antenna module 1420 and the transceiver 1410. The communication and processing circuitry 1441 can also be configured to execute communication and processing software 1451 stored on the computer-readable medium 1406 to implement one or more of the functions described herein.

[0166] In some aspects of the disclosure, the processor 1404 can include data structure selection circuitry 1442 configured for various functions, including, for example, selecting a data structure for transmitting a discovery message, such as a first data structure (e.g., 1028 of Figure 10 ), which is illustrated as a SL DRB formatted PDCP data PDU for groupcast and broadcast transmissions, a second data structure (e.g., 1030 of Figure 10 ), which is illustrated as a SL DRB formatted PDCP data PDU for unicast transmissions, and a third data structure (e.g., 1032 of Figure 111128) or any combination thereof. In some examples, data structure selection circuitry 1442 may include one or more hardware components that provide a physical structure that performs processes associated with executing a data structure, such as the first, second, third, or combined data structure. Data structure selection circuitry 1442 may also be configured to execute data structure selection software 1452 stored on computer-readable medium 1406 to implement one or more functions described herein.

[0167] In some aspects of the present disclosure, the processor 1404 may include a data structure construction circuit 1443 configured for various functions, including, for example, constructing a data structure for transmitting a discovery message, such as a first data structure illustrated as a SL DRB formatted PDCP data PDU for multicast and broadcast transmission (e.g., Figure 10 1028), is illustrated as a second data structure of a PDCP data PDU formatted as a SL DRB for unicast transmission (eg, Figure 10 1030), and a third data structure (eg, Figure 11 In some examples, the data structure construction circuit 1443 may include one or more hardware components that provide a physical structure for performing processes related to performing data structure construction of a discovery message, such as a first data structure (e.g., a PDCP data PDU formatted as a SL DRB for multicast and broadcast transmission) exemplified. Figure 10 1028), is illustrated as a second data structure of a PDCP data PDU formatted as a SL DRB for unicast transmission (eg, Figure 10 1030), and a third data structure (e.g., Figure 11of the data structure construction software 1453 stored on the computer- readable medium 1406 to implement one or more functions described herein. In some aspects of the disclosure, the processor 1404 can include discovery message priority handling circuitry 1444 configured for various functions including, for example, enforcing a priority level of a discovery message transmitted on a physical sidelink shared channel (PSSCH) to be lower than other messages transmitted on a physical sidelink control channel (PSCCH), or, for example, establishing a priority of a discovery message to be at least one of: based on a logical channel (LCH) priority of a logical channel (LCH) that transmits the discovery message, or fixed to be a highest priority among messages transmitted on a sidelink transport channel (STCH). The discovery message can be a PC5 discovery message. In some examples, the discovery message priority handling circuitry 1444 can include one or more hardware components that provide a physical structure that performs processes related to the performance of discovery message priority handling. The discovery message priority handling circuitry 1444 can also be configured to execute discovery message priority handling software 1454 stored on the computer-readable medium 1406 to implement one or more functions described herein.

[0168] In some aspects of the disclosure, the processor 1404 can include service and resource determination circuitry 1445 configured for various functions including, for example, determining to use a service associated with sidelink communication, determining content of a discovery message including an indication that the message is a discovery message for the service, and / or determining a sidelink resource for transmitting the discovery message. In some examples, the service and resource determination circuitry 1445 can include one or more hardware components that provide a physical structure that performs processes related to the determinations, for example. The service and resource determination circuitry 1445 can also be configured to execute service and resource determination software 1455 stored on the computer-readable medium 1406 to implement one or more functions described herein.

[0169] Figure 15 FIG. 15 shows a flowchart of an example process 1500 (e.g., a method) at a remote UE configured for PC5 communication, such as the UE 1400, for transmitting a discovery message over a user plane using a data structure including a parameter indicating the discovery message, in accordance with some aspects of the present disclosure. As described below, some or all illustrated features can be omitted in some implementations, and some illustrated features can not be required in the implementation of all examples. In some examples, the process 1500 can be carried out by the UE 1400, by the processor 1404, by the discovery message priority handling circuitry 1444, by the service and resource determination circuitry 1445, or by some combination of these. Figure 14In some examples, process 1500 can be performed by any suitable equipment or means for performing the functions or algorithms described herein.

[0170] At block 1502, a first UE may detect a failure in establishing or maintaining a connection with a base station; in other words, the UE may identify and react to the failure in establishing or maintaining a connection with the base station. At block 1504, the UE may send a discovery message via a user plane using a data structure including parameters indicating a discovery message. According to some aspects, the discovery message may be a PC5 discovery message, which may have content created by a PC5 discovery layer of the first UE's protocol stack.

[0171] In some examples, the first UE may send the discovery message as at least one of a broadcast message or a multicast message. In some examples, the UE may send the discovery message as at least one of the following messages: an announcement discovery message as a broadcast or multicast message that may announce the first UE's ability to send user data, control signaling, or both to a second UE that relays user data, control signaling, or both (collectively referred to as traffic) to a base station; or a response discovery message as a unicast message in response to a request discovery message from a second UE.

[0172] According to some aspects, the UE may also establish a one-to-one connection with a second UE, and the one-to-one connection between the first UE and the second UE may be scheduled by the first UE. According to some aspects, relaying user data, control signaling, or both by the second UE may be implemented according to at least one of a layer 2 relay process or a layer 3 relay process. In some examples, the first UE may establish a single-hop relay between the first UE, which may be outside the air interface coverage area of ​​the base station, and the second UE, which may be within the air interface coverage area of ​​the base station, and maintain the second UE connection with the base station over the air interface.

[0173] In some examples, the protocol stack of the first UE may include: a physical layer, a medium access control (MAC) layer on the physical layer, a radio link control (RLC) layer on the MAC layer, a packet data convergence protocol (PDCP) layer on the RLC layer, a service data adaptation protocol (SDAP) layer on the PDCP layer, and a PC5 discovery layer on the SDAP layer. According to one aspect, encryption and integrity protection are not performed in the PDCP layer.

[0174] In other examples, the protocol stack of the first UE may include: a physical layer, a media access control (MAC) layer on the physical layer, and a PC5 discovery layer on the MAC layer. In some aspects, the protocol stack of the first UE may include a PC5 discovery layer and at least one of: a packet data convergence protocol (PDCP) layer (a parameter indicating a discovery message may be a service data unit (SDU) type); or a media access control (MAC) layer (a parameter indicating a discovery message may be a logical channel ID (LCID)); or a combination thereof. In some examples, the value of the SDU type and / or LCID that may correspond to a PC5 discovery message may indicate that the discovery message may be a PC5 discovery message, which may have content created by the PC5 discovery layer of the protocol stack of the first UE. In some examples, the LCID may be fixed.

[0175] According to some aspects, a discovery message may be transmitted on a physical bypass shared channel (PSSCH) and may have the lowest priority among messages transmitted on a physical bypass control channel (PSCCH). A discovery message may be transmitted on a bypass transport channel (STCH) and may have a lower priority than other messages transmitted on the physical bypass control channel (PSCCH). According to other aspects, the priority of the discovery message is the highest among messages transmitted on the bypass transport channel (STCH). In other aspects, the priority of the discovery message may be at least one of: based on the logical channel (LCH) priority of the logical channel on which the discovery message is transmitted; or fixed to the highest priority among messages transmitted on the bypass transport channel (STCH).

[0176] In one configuration, a first UE (e.g., UE 1400) processing a discovery method in a wireless communication network includes means for detecting a failure to establish or maintain a connection with a base station, and means for sending a discovery message over a user plane using a data structure including parameters indicating a discovery message. In one aspect, the aforementioned means may be Figure 14 The processor 1404 shown in FIG is configured to perform the functions listed in the aforementioned means. On the other hand, the aforementioned means may be a circuit or any equipment configured to perform the functions listed in the aforementioned means.

[0177] Figure 16is a flow diagram illustrating an exemplary process 1600 (e.g., a method) at a relay UE (first UE) (such as UE 1400) configured for PC5 communication, for transmitting a discovery message over a user plane with a data structure including parameters indicative of the discovery message, in accordance with some aspects of the present disclosure. As described below, in particular implementations within the scope of the present disclosure, some or all illustrated features can be omitted in some examples, and some illustrated features can not be required for implementation of all examples. In some examples, the process 1600 can be performed by the UE 1400 illustrated in FIG. 14. In some examples, the process 1600 can be performed by any suitable apparatus or means for performing the functions or algorithm described herein. Figure 14 The process 1600 can be implemented by the UE 1400 illustrated in FIG. 14, in some examples. In some examples, the process 1600 can be performed by any suitable apparatus or means for performing the functions or algorithm described herein.

[0178] At block 1602, the first UE can transmit a discovery message over a user plane with a data structure including parameters indicative of the discovery message. At block 1604, the first UE can establish a one-to-one connection with a second UE that responds to the discovery message. According to some aspects, the discovery message can be a PC5 discovery message, which can have content created by a PC5 discovery layer of a protocol stack of the first UE.

[0179] In some examples, the first UE can transmit the discovery message as at least one of a broadcast message or a groupcast message. In some examples, the first UE can transmit the discovery message as at least one of: an announcement discovery message as a broadcast or groupcast message, which can announce a capability of the first UE to participate in relaying traffic of the second UE to a base station; or a response discovery message as a unicast message, which can respond to a request discovery message from the second UE.

[0180] According to some aspects, the first UE can schedule the one-to-one connection between the first UE and the second UE. In some aspects, the first UE can relay user data, control signaling, or both (collectively, traffic) between the second UE and the base station according to at least one of: a layer 3 relay procedure; or a layer 3 relay procedure. In some aspects, the first UE can also establish a single-hop relay between the second UE, which can be outside an air interface coverage area of the base station, and the first UE, which can be inside the air interface coverage area of the base station, and maintain a connection with the base station over an air interface.

[0181] In some examples, the protocol stack of the first UE may include: a physical layer, a medium access control (MAC) layer above the physical layer, a radio link control (RLC) layer above the MAC layer, a packet data convergence protocol (PDCP) layer above the RLC layer, a service data adaptation protocol (SDAP) layer above the PDCP layer, and a PC5 discovery layer above the SDAP layer. In some examples, encryption and integrity protection may not be performed in the PDCP layer. According to other aspects, the protocol stack of the first UE may include: a physical layer, a medium access control (MAC) layer above the physical layer, and a PC5 discovery layer above the MAC layer. In some examples, the protocol stack of the first UE may include: a packet data convergence protocol (PDCP) layer (where, for example, a parameter indicating a discovery message may be a service data unit (SDU) type); a medium access control (MAC) layer (where, for example, a parameter indicating a discovery message may be a logical channel ID (LCID)); or a combination thereof. In some examples, the value of the SDU type and / or LCID corresponding to the PC5 discovery message indicates that the discovery message may be a PC5 discovery message. In some examples, the LCID may be fixed.

[0182] According to some aspects, a discovery message may be transmitted on a physical bypass shared channel (PSSCH) and may have the lowest priority among messages transmitted on a physical bypass control channel (PSCCH). In other aspects, a discovery message may be transmitted on a bypass transport channel (STCH) and may have a lower priority than other messages transmitted on the physical bypass control channel (PSCCH). In other aspects, the priority of a discovery message may be the highest among messages transmitted on a bypass transport channel (STCH). In some examples, the priority of a discovery message may be based on the logical channel (LCH) priority of the logical channel on which the discovery message is transmitted, or may be fixed to be the highest priority among messages transmitted on a bypass transport channel (STCH).

[0183] In one configuration, a first UE (e.g., UE 1400) processing a discovery method in a wireless communication network includes means for sending a discovery message over a user plane using a data structure including parameters indicating the discovery message, and means for establishing a one-to-one connection with a second UE that responds to the discovery message. In one aspect, the aforementioned means may be Figure 14 The processor 1404 shown in FIG is configured to perform the functions listed in the aforementioned means. On the other hand, the aforementioned means may be a circuit or any equipment configured to perform the functions listed in the aforementioned means.

[0184] Figure 17is a flow diagram illustrating an exemplary process 1700 (e.g., a method) at a relay UE (first UE) (such as UE 1400) configured for PC5 communication, in accordance with some aspects of the present disclosure. As described below, in particular implementations some or all of the features illustrated can be omitted in some implementations, and some illustrated features can not be required for implementation of all examples. In some examples, process 1700 can be carried out by the UE 1400 illustrated in FIG. 14. In some examples, process 1700 can be carried out by any suitable apparatus or means for carrying out the functions or algorithm described herein. Figure 14 In some examples, process 1700 can be carried out by the UE 1400 illustrated in FIG. 14. In some examples, process 1700 can be carried out by any suitable apparatus or means for carrying out the functions or algorithm described herein.

[0185] At block 1702, the first UE can determine to use a service associated with sidelink communication. At block 1704, the first UE can determine content of a discovery message including an indication that the message is a discovery message for the service. At block 1706, the first UE can determine a sidelink resource for transmitting the discovery message. At block 1708, the first UE can transmit, over a user plane, the discovery message including the indication that the message is a discovery message for the service using the determined sidelink resource.

[0186] In one example, the first UE can also transmit, over the user plane, the discovery message using the determined sidelink resource, where an upper layer protocol header indicates that the discovery message can be at least one of an announce discovery message, a request discovery message, or a response to the request discovery message. In some aspects, the announce discovery message can be a sidelink Model A query, which can be at least one of a broadcast or a groupcast, the request discovery message can be a sidelink Model B query, which can be at least one of a broadcast or a groupcast, and the response to the received request discovery message can be a unicast sidelink Model B response.

[0187] In another example, the first UE may also include an indication that the message is a discovery message in at least one of a packet data convergence protocol (PDCP) data packet data unit (PDU) of a PDCP entity associated with a user plane or a media access control (MAC) packet data unit (PDU) of a MAC entity associated with a user plane, and configure the content of the discovery message at an upper layer protocol, which may be above at least one of the PDCP protocol layer or the MAC protocol layer. In some aspects, the upper layer protocol may be a PC5 discovery layer protocol. In other aspects, the content of the discovery message is included in a header of the upper layer protocol, and the indication that the message is a discovery message may be included in a PDCP data PDU. In other aspects, the PDCP data PDU has a data structure including a service data unit (SDU) type, and the value of the SDU type indicates that the discovery message may be at least one of a PC5 discovery message, an advertised discovery message, or a requested discovery message, wherein the type of the discovery message may be included in a header of the upper layer protocol, or be a response to a received requested discovery message. In some examples, the announce discovery message can be a bypass model A query, which can be at least one of broadcast or multicast, the request discovery message can be a bypass model B query, which can be at least one of broadcast or multicast, and the response to the received request discovery message can be a unicast bypass model B response.

[0188] According to some aspects, the content of the discovery message is included in a header of an upper layer protocol, and an indication that the message is a discovery message can be included in a MAC subheader of a MAC PDU. In some examples, the MAC subheader has a data structure including a logical channel identifier (LCID), and the LCID value indicates that the discovery message can be at least one of a PC5 discovery message, an advertised discovery message, or a requested discovery message, wherein the type of the discovery message can be included in the header of the upper layer protocol, or a response to a received requested discovery message. In other examples, the advertised discovery message can be a bypass model A query, which can be at least one of broadcast or multicast, the requested discovery message can be a bypass model B query, which can be at least one of broadcast or multicast, and the response to the received requested discovery message can be a unicast bypass model B response.

[0189] In other aspects, the bypass resource may be a physical bypass shared channel (PSSCH).In one example, the first UE may also send the discovery message as at least one of a broadcast message or a multicast message.

[0190] In one example, the first UE may also send the discovery message as at least one of the following messages: an announcement discovery message as a broadcast or multicast message, which announces the first UE's ability to send user data, control signaling, or both to a second UE that relays user data, control signaling, or both to a base station, or a response discovery message as a unicast message in response to a request discovery message from the second UE.

[0191] In one example, the first UE may also send the discovery message as at least one of the following messages: an announcement discovery message as a broadcast or multicast message, which announces the first UE's ability to relay user data, control signaling, or both from the second UE to the base station; or a response discovery message as a unicast message in response to a request discovery message from the second UE.

[0192] In another example, the first UE may also establish a one-to-one connection with the second UE, and relay user data, control signaling, or both to the base station through the second UE according to at least one of a layer 2 relay process or a layer 3 relay process.

[0193] In yet another example, the first UE may also establish a one-to-one connection with the second UE, and relay user data, control signaling, or both from the second UE to the base station according to at least one of a layer 2 relay procedure or a layer 3 relay procedure.

[0194] According to some aspects, the first UE may additionally establish a single-hop relay between the first UE, which may be outside the air interface coverage area of ​​the base station, and a second UE, which may be within the air interface coverage area of ​​the base station, and maintain the second UE connection with the base station over the air interface.

[0195] According to some aspects, the first UE also establishes a single-hop relay between the second UE that may be outside the air interface coverage area of ​​the base station and the first UE that may be within the air interface coverage area of ​​the base station, and maintains a connection with the base station over the air interface.

[0196] In one example, the protocol stack of the first UE may include: a physical layer, a medium access control (MAC) layer on the physical layer, a radio link control (RLC) layer on the MAC layer, a packet data convergence protocol (PDCP) layer on the RLC layer, a service data adaptation protocol (SDAP) layer on the PDCP layer, and a PC5 discovery layer on the SDAP layer. In one example, encryption and integrity protection are not performed in the PDCP layer.

[0197] According to some aspects, the protocol stack of the first UE may include a physical layer, a medium access control (MAC) layer on the physical layer, and a PC5 discovery layer on the MAC layer.

[0198] According to other aspects, the protocol stack of the first UE includes a PC5 discovery layer and at least one of the following layers: a packet data convergence protocol (PDCP) layer, wherein the indication that the message is a discovery message can be represented by an indication service data unit (SDU) type of the PDCP data PDU; a medium access control (MAC) layer, wherein the indication that the message is a discovery message can be a logical channel identifier (LCID); or a combination thereof.

[0199] In one example, the discovery message may be transmitted on a physical bypass shared channel (PSSCH) and have the lowest priority among messages transmitted on a physical bypass control channel (PSCCH). In another example, the discovery message may be transmitted on a bypass transport channel (STCH) and have a lower priority than other messages transmitted on the physical bypass control channel (PSCCH).

[0200] In some aspects, the priority of the discovery message is the highest among messages transmitted on the side transport channel (STCH). In one example, the priority of the discovery message can be at least one of: based on the logical channel priority of the logical channel (LCH) on which the discovery message is transmitted, or fixed to be the highest priority among messages transmitted on the side transport channel (STCH).

[0201] In one configuration, a first UE (e.g., UE 1400) processing a discovery method in a wireless communication network includes: means for determining to use a service associated with bypass communication; means for determining the content of a discovery message including an indication that the message is a discovery message for a service; means for determining a bypass resource for sending the discovery message; and means for sending the discovery message including an indication that the message is a discovery message for a service through a user plane using the determined bypass resource. In one aspect, the aforementioned means may be Figure 14 The processor 1404 shown in FIG is configured to perform the functions listed in the aforementioned means. On the other hand, the aforementioned means may be a circuit or any equipment configured to perform the functions listed in the aforementioned means.

[0202] Of course, in the above examples, the circuits included in the processor are provided merely as examples, and other means for performing the described functions may be included in various aspects of the present disclosure, including but not limited to instructions stored in the computer-readable medium 1406, or in Figure 1-Figure 3 and 6- Figure 14 and any other suitable equipment or devices described in any of the foregoing, and utilizing, for example, Figure 15 、 Figure 16 and / or Figure 17 Describe the process and / or algorithm.

[0203] Several aspects of wireless communication networks have been described with reference to exemplary implementations. As those skilled in the art will readily appreciate, various aspects described throughout this disclosure may be extended to other telecommunication systems, network architectures, and communication standards.

[0204] For example, various aspects may be implemented in other systems defined by 3GPP, such as Long Term Evolution (LTE), Evolved Packet System (EPS), Universal Mobile Telecommunications System (UMTS), and / or Global System for Mobile Communications (GSM). Various aspects may also be extended to systems defined by the 3rd Generation Partnership Project 2 (3GPP2), such as CDMA2000 and / or Evolution-Data Optimized (EV-DO). Other examples may be implemented in systems employing IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Ultra-Wideband (UWB), Bluetooth, and / or other suitable systems. The actual telecommunication standard, network architecture, and / or communication standard employed will depend on the specific application and the overall design constraints imposed on the system.

[0205] In this disclosure, the word "exemplary" is used to mean "serving as an example, instance, or illustration." Any implementation or aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects of the disclosure. Likewise, the term "aspect" does not require that all aspects of the disclosure include the feature, advantage, or mode of operation discussed. The term "coupled" as used herein refers to a direct or indirect coupling between two objects. For example, if object A physically contacts object B, and object B contacts object C, then objects A and C can still be considered to be coupled to each other - even if they are not in direct physical contact with each other. For example, a first object can be coupled to a second object even if the first object has never been in direct physical contact with the second object. The terms "circuit" and "circuitry" are used broadly and are intended to include hardware implementations of both electrical devices and conductors that, when connected and configured, achieve the performance of the functionality described in this disclosure, without limitation to types of electronic circuitry, as well as software implementations of information and instructions that, when executed by a processor, achieve the performance of the functionality described in this disclosure.

[0206] Figures 1-17 One or more components, steps, features and / or functions shown in the drawings may be rearranged and / or combined into a single component, step, feature or function, or may be embodied in several components, steps or functions. Additional elements, components, steps and / or functions may also be added without departing from the novel features disclosed herein. Figures 1-17 The equipment, devices and / or components shown in the can be configured to perform one or more methods, features or steps described herein. The novel algorithms described herein can also be effectively implemented in software and / or embedded in hardware.

[0207] It is understood that the specific order or hierarchy of steps in the disclosed methods is an illustration of exemplary processes. Based on design preferences, it is understood that the specific order or hierarchy of steps in the methods may be rearranged. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented unless specifically stated therein.

[0208] The foregoing description is provided to enable those 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 general 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 to conform to the full scope consistent with the language of the claims, wherein, unless otherwise stated, elements in the singular are not intended to mean "one and only one," but rather "one or more." Unless otherwise specified, the term "some" refers to one or more. Phrases referring to "at least one" of a series of items refer to any combination of these items, including individual members. For example, "at least one of a, b, or c" is intended to cover a; b; c; a and b; a and c; b and c; similarly, the structure "a and / or b" refers to any combination of these items, including individual members. As an example, "a and / or b" is intended to cover: a, b, and a and b. All structural and functional equivalents of the elements throughout the various aspects described in this disclosure that are known or will later be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.

Claims

1. A discovery method in a wireless communication network, the method comprising: Determine the use of services associated with bypass communications; determining content of a discovery message including an indication that the message is a discovery message for a service; determining a bypass resource for sending a discovery message; and sending, using the determined bypass resources, a discovery message including an indication that the message is a discovery message for a service to one or more neighboring UEs via a user interface; The UE protocol stack includes a PC5 discovery layer and at least one of the following: a Packet Data Convergence Protocol (PDCP) layer, wherein the indication that the message is a discovery message is indicated by an indicated Service Data Unit (SDU) type of a PDCP data packet data unit (PDU); a medium access control (MAC) layer, wherein the indication that the message is a discovery message is represented by a logical channel identifier (LCID); or A combination of the PDCP layer and the MAC layer.

2. The method according to claim 1, further comprising: Sending a discovery message over a user plane using the determined bypass resource, wherein an upper layer protocol header indicates that the discovery message is at least one of: Announcement discovery news, Request a discovery message, or Response to a request-discover message.

3. The method according to claim 2, wherein: The announcement discovery message is at least one of a broadcast or multicast bypass model A query; Requesting that the discovery message be a bypass Model B query that is at least one of a broadcast or a multicast; and The response to a received Request Discovery message is a unicast Bypass Model B response.

4. The method according to claim 1, further comprising: An indication that the message is a discovery message is included in at least one of the following: PDCP data PDUs of the PDCP entity associated with the user plane, or MAC PDUs of the MAC entity associated with the user plane; and The content of the discovery message is configured at an upper layer protocol above at least one of the PDCP protocol layer or the MAC protocol layer.

5. The method according to claim 4, wherein The upper layer protocol is the PC5 discovery layer protocol.

6. The method according to claim 4, wherein: The content of the discovery message is included in a header of an upper layer protocol, and an indication that the message is a discovery message is included in a PDCP data PDU.

7. The method according to claim 6, wherein: The PDCP data PDU has a data structure including the SDU type, and a value of the SDU type indicates that the discovery message is at least one of the following: PC5 discovery message, advertise discovery message, or request discovery message, wherein the type of discovery message is included in the header of the upper layer protocol, or A response to a received request-discover message.

8. The method according to claim 7, wherein: The announcement discovery message is at least one of a broadcast or multicast bypass model A query; Requesting that the discovery message be a bypass Model B query that is at least one of broadcast or multicast; and The response to a received Request Discovery message is a unicast Bypass Model B response.

9. The method according to claim 4, wherein: The content of the discovery message is included in a header of an upper layer protocol, and an indication that the message is a discovery message is included in a MAC subheader of a MAC PDU.

10. The method according to claim 9, wherein: The MAC subheader has a data structure including the LCID, and a value of the LCID indicates that the discovery message is at least one of the following: PC5 discovery message, advertise discovery message, or request discovery message, wherein the type of discovery message is included in the header of the upper layer protocol, or A response to a received request-discover message.

11. The method according to claim 10, wherein: The announcement discovery message is at least one of a broadcast or multicast bypass model A query; Requesting that the discovery message be a bypass Model B query that is at least one of broadcast or multicast; and The response to a received Request Discovery message is a unicast Bypass Model B response.

12. The method according to claim 1, wherein The bypass resource is the physical bypass shared channel PSSCH.

13. The method according to claim 1, further comprising: The discovery message is sent as at least one of a broadcast message or a multicast message.

14. The method according to claim 1, further comprising: The discovery message is sent as at least one of the following: an announce discovery message that is a broadcast or multicast message announcing the capability of the UE to send user data, control signaling, or both to a second UE that relays the user data, control signaling, or both to the base station; or A response discovery message that is a unicast message in response to the request discovery message from the second UE.

15. The method according to claim 1, further comprising: The discovery message is sent as at least one of the following: an announce discovery message that is a broadcast or multicast message announcing the capability of the UE to relay user data, control signaling, or both from a second UE to the base station; or A response discovery message that is a unicast message in response to the request discovery message from the second UE.

16. The method according to claim 1, further comprising: Establishing a one-to-one connection with the second UE; and User data, control signaling, or both are relayed to the base station by the second UE according to at least one of a layer 2 relay procedure or a layer 3 relay procedure.

17. The method according to claim 1, further comprising: Establishing a one-to-one connection with the second UE; and User data, control signaling, or both are relayed from the second UE to the base station according to at least one of a layer 2 relay procedure or a layer 3 relay procedure.

18. The method of claim 1, further comprising establishing a single-hop relay between a UE outside the air interface coverage area of ​​the base station and a second UE within the air interface coverage area of ​​the base station, and maintaining the second UE connection with the base station over the air interface.

19. The method according to claim 1, further comprising establishing a single-hop relay between a second UE outside the air interface coverage area of ​​the base station and a UE within the air interface coverage area of ​​the base station, and maintaining a connection with the base station through the air interface.

20. The method according to claim 1, wherein The protocol stack of the UE includes: A physical layer, the MAC layer on the physical layer, a radio link control RLC layer on the MAC layer, the PDCP layer on the RLC layer, a service data adaptation protocol SDAP layer on the PDCP layer, and the PC5 discovery layer on the SDAP layer.

21. The method according to claim 20, wherein Ciphering and integrity protection are not performed in the PDCP layer.

22. The method according to claim 1, wherein The protocol stack of the UE includes: A physical layer, the MAC layer on the physical layer, and the PC5 discovery layer on the MAC layer.

23. The method according to claim 1, wherein The discovery message is transmitted on the physical bypass shared channel PSSCH and has the lowest priority among the messages transmitted on the physical bypass control channel PSCCH.

24. The method according to claim 1, wherein The discovery message is transmitted on the bypass transport channel STCH and has a lower priority than other messages transmitted on the physical bypass control channel PSCCH.

25. The method according to claim 1, wherein The priority of the discovery message is the highest among the messages transmitted on the bypass transmission channel STCH.

26. The method according to claim 1, wherein The priority of a discovery message is at least one of the following: Based on the logical channel priority of the logical channel LCH on which the discovery message is transmitted; or Fixed as the highest priority among messages transmitted on the bypass transmission channel STCH.

27. An apparatus for performing wireless communication at a user equipment (UE) in a wireless communication network, comprising: Wireless transceiver; Memory; and a processor communicatively coupled to the wireless transceiver and the memory, wherein the processor and the memory are configured to: Determine the use of services associated with bypass communications; determining content of a discovery message including an indication that the message is a discovery message for a service; determining a bypass resource for sending a discovery message; and sending, through the user interface, a discovery message including an indication that the message is a discovery message for a service to one or more neighboring UEs using the determined bypass resource, The UE protocol stack includes a PC5 discovery layer and at least one of the following: a Packet Data Convergence Protocol (PDCP) layer, wherein the indication that the message is a discovery message is indicated by an indicated Service Data Unit (SDU) type of a PDCP data packet data unit (PDU); a medium access control (MAC) layer, wherein the indication that the message is a discovery message is represented by a logical channel identifier (LCID); or A combination of the PDCP layer and the MAC layer.

28. An apparatus for performing wireless communication at a user equipment (UE) in a wireless communication network, comprising: means for determining to use a service associated with bypass communication; means for determining content of a discovery message including an indication that the message is a discovery message for a service; means for determining bypass resources for sending a discovery message; and means for sending, through a user interface, a discovery message including an indication that the message is a discovery message for a service to one or more neighboring UEs using the determined bypass resources, The UE protocol stack includes a PC5 discovery layer and at least one of the following: a Packet Data Convergence Protocol (PDCP) layer, wherein the indication that the message is a discovery message is indicated by an indicated Service Data Unit (SDU) type of a PDCP data packet data unit (PDU); a medium access control (MAC) layer, wherein the indication that the message is a discovery message is represented by a logical channel identifier (LCID); or A combination of the PDCP layer and the MAC layer.

29. A computer-readable medium having program code recorded thereon, wherein: The program code is executed by one or more processors of a user equipment (UE) so that the processors perform the method according to any one of claims 1 to 26.

Images