Patent ID: 12245106

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Example Communications System and Networks

The 3rd Generation Partnership Project (3GPP) develops technical standards for cellular telecommunications network technologies, including radio access, the core transport network, and service capabilities—including work on codecs, security, and quality of service. Recent radio access technology (RAT) standards include WCDMA (commonly referred as 3G), LTE (commonly referred as 4G), LTE-Advanced standards, and New Radio (NR), which is also referred to as “5G”. 3GPP NR standards development is expected to continue and include the definition of next generation radio access technology (new RAT), which is expected to include the provision of new flexible radio access below 7 GHz, and the provision of new ultra-mobile broadband radio access above 7 GHz. The flexible radio access is expected to consist of a new, non-backwards compatible radio access in new spectrum below 7 GHz, and it is expected to include different operating modes that may be multiplexed together in the same spectrum to address a broad set of 3GPP NR use cases with diverging requirements. The ultra-mobile broadband is expected to include cmWave and mmWave spectrum that will provide the opportunity for ultra-mobile broadband access for, e.g., indoor applications and hotspots. In particular, the ultra-mobile broadband is expected to share a common design framework with the flexible radio access below 7 GHz, with cmWave and mmWave specific design optimizations.

3GPP has identified a variety of use cases that NR is expected to support, resulting in a wide variety of user experience requirements for data rate, latency, and mobility. The use cases include the following general categories: Enhanced Mobile Broadband (eMBB) Ultra-Reliable Low-Latency Communication (URLLC), Massive Machine Type Communications (mMTC), network operation (e.g., network slicing, routing, migration and interworking, energy savings), and Enhanced Vehicle-to-Everything (eV2X) communications, which may include any of Vehicle-to-Vehicle Communication (V2V), Vehicle-to-Infrastructure Communication (V2I), Vehicle-to-Network Communication (V2N), Vehicle-to-Pedestrian Communication (V2P), and vehicle communications with other entities. Specific service and applications in these categories include, e.g., monitoring and sensor networks, device remote controlling, bi-directional remote controlling, personal cloud computing, video streaming, wireless cloud-based office, first responder connectivity, automotive eCall, disaster alerts, real-time gaming, multi-person video calls, autonomous driving, augmented reality, tactile internet, virtual reality, home automation, robotics, and aerial drones to name a few. All of these use cases and others are contemplated herein.

FIG.1Aillustrates an example communications system100in which the systems, methods, and apparatuses described and claimed herein may be used. The communications system100may include wireless transmit/receive units (WTRUs)102a,102b,102c,102d,102e,102f, and/or102g, which generally or collectively may be referred to as WTRU102or WTRUs102. The communications system100may include, a Radio Access Network (RAN)103/104/105/103b/104b/105b, a core network106/107/109, a public switched telephone network (PSTN)108, the Internet110, other networks112, and Network Services113.113. Network Services113may include, for example, a V2X server, V2X functions, a ProSe server, ProSe functions, IoT services, video streaming, and/or edge computing, etc.

It will be appreciated that the concepts disclosed herein may be used with any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs102may be any type of apparatus or device configured to operate and/or communicate in a wireless environment. In the example ofFIG.1A, each of the WTRUs102is depicted inFIGS.1A-1Eas a hand-held wireless communications apparatus. It is understood that with the wide variety of use cases contemplated for wireless communications, each WTRU may comprise or be included in any type of apparatus or device configured to transmit and/or receive wireless signals, including, by way of example only, user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a tablet, a netbook, a notebook computer, a personal computer, a wireless sensor, consumer electronics, a wearable device such as a smart watch or smart clothing, a medical or eHealth device, a robot, industrial equipment, a drone, a vehicle such as a car, bus or truck, a train, or an airplane, and the like.

The communications system100may also include a base station114aand a base station114b. In the example ofFIG.1A, each base stations114aand114bis depicted as a single element. In practice, the base stations114aand114bmay include any number of interconnected base stations and/or network elements. Base stations114amay be any type of device configured to wirelessly interface with at least one of the WTRUs102a,102b, and102cto facilitate access to one or more communication networks, such as the core network106/107/109, the Internet110, Network Services113, and/or the other networks112. Similarly, base station114bmay be any type of device configured to wiredly and/or wirelessly interface with at least one of the Remote Radio Heads (RRHs)118a,118b, Transmission and Reception Points (TRPs)119a,119b, and/or Roadside Units (RSUs)120aand120bto facilitate access to one or more communication networks, such as the core network106/107/109, the Internet110, other networks112, and/or Network Services113. RRHs118a,118bmay be any type of device configured to wirelessly interface with at least one of the WTRUs102, e.g., WTRU102c, to facilitate access to one or more communication networks, such as the core network106/107/109, the Internet110, Network Services113, and/or other networks112.

TRPs119a,119bmay be any type of device configured to wirelessly interface with at least one of the WTRU102d, to facilitate access to one or more communication networks, such as the core network106/107/109, the Internet110, Network Services113, and/or other networks112. RSUs120aand120bmay be any type of device configured to wirelessly interface with at least one of the WTRU102eor102f, to facilitate access to one or more communication networks, such as the core network106/107/109, the Internet110, other networks112, and/or Network Services113. By way of example, the base stations114a,114bmay be a Base Transceiver Station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a Next Generation Node-B (gNode B), a satellite, a site controller, an access point (AP), a wireless router, and the like.

The base station114amay be part of the RAN103/104/105, which may also include other base stations and/or network elements (not shown), such as a Base Station Controller (BSC), a Radio Network Controller (RNC), relay nodes, etc. Similarly, the base station114bmay be part of the RAN103b/104b/105b, which may also include other base stations and/or network elements (not shown), such as a BSC, a RNC, relay nodes, etc. The base station114amay be configured to transmit and/or receive wireless signals within a particular geographic region, which may be referred to as a cell (not shown). Similarly, the base station114bmay be configured to transmit and/or receive wired and/or wireless signals within a particular geographic region, which may be referred to as a cell (not shown). The cell may further be divided into cell sectors. For example, the cell associated with the base station114amay be divided into three sectors. Thus, for example, the base station114amay include three transceivers, e.g., one for each sector of the cell. The base station114amay employ Multiple-Input Multiple Output (MIMO) technology and, therefore, may utilize multiple transceivers for each sector of the cell, for instance.

The base station114amay communicate with one or more of the WTRUs102a,102b,102c, and102gover an air interface115/116/117, which may be any suitable wireless communication link (e.g., Radio Frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface115/116/117may be established using any suitable Radio Access Technology (RAT).

The base station114bmay communicate with one or more of the RRHs118aand118b, TRPs119aand119b, and/or RSUs120aand120b, over a wired or air interface115b/116b/117b, which may be any suitable wired (e.g., cable, optical fiber, etc.) or wireless communication link (e.g., RF, microwave, IR, UV, visible light, cmWave, mmWave, etc.). The air interface115b/116b/117bmay be established using any suitable RAT.

The RRHs118a,118b, TRPs119a,119band/or RSUs120a,120b, may communicate with one or more of the WTRUs102c,102d,102e,102fover an air interface115c/116c/117c, which may be any suitable wireless communication link (e.g., RF, microwave, IR, ultraviolet UV, visible light, cmWave, mmWave, etc.) The air interface115c/116c/117cmay be established using any suitable RAT.

The WTRUs102may communicate with one another over a direct air interface115d/116d/117d, such as Sidelink communication which may be any suitable wireless communication link (e.g., RF, microwave, IR, ultraviolet UV, visible light, cmWave, mmWave, etc.) The air interface115d/116d/117dmay be established using any suitable RAT.

The communications system100may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station114ain the RAN103/104/105and the WTRUs102a,102b,102c, or RRHs118a,118b, TRPs119a,119band/or RSUs120aand120bin the RAN103b/104b/105band the WTRUs102c,102d,102e, and102f, may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface115/116/117and/or115c/116c/117crespectively using Wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink Packet Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA).

The base station114ain the RAN103/104/105and the WTRUs102a,102b,102c, and102g, or RRHs118aand118b, TRPs119aand119b, and/or RSUs120aand120bin the RAN103b/104b/105band the WTRUs102c,102d, may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface115/116/117or115c/116c/117crespectively using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A), for example. The air interface115/116/117or115c/116c/117cmay implement 3GPP NR technology. The LTE and LTE-A technology may include LTE D2D and/or V2X technologies and interfaces (such as Sidelink communications, etc.) Similarly, the 3GPP NR technology may include NR V2X technologies and interfaces (such as Sidelink communications, etc.)

The base station114ain the RAN103/104/105and the WTRUs102a,102b,102c, and102gor RRHs118aand118b, TRPs119aand119b, and/or RSUs120aand120bin the RAN103b/104b/105band the WTRUs102c,102d,102e, and102fmay implement radio technologies such as IEEE 802.16 (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1×, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like.

The base station114cinFIG.1Amay be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a train, an aerial, a satellite, a manufactory, a campus, and the like. The base station114cand the WTRUs102, e.g., WTRU102e, may implement a radio technology such as IEEE 802.11 to establish a Wireless Local Area Network (WLAN). Similarly, the base station114cand the WTRUs102, e.g., WTRU102d, may implement a radio technology such as IEEE 802.15 to establish a Wireless Personal Area Network (WPAN). The base station114cand the WTRUs102, e.g., WRTU102e, may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, NR, etc.) to establish a picocell or femtocell. As shown inFIG.1A, the base station114cmay have a direct connection to the Internet110. Thus, the base station114cmay not be required to access the Internet110via the core network106/107/109.

The RAN103/104/105and/or RAN103b/104b/105bmay be in communication with the core network106/107/109, which may be any type of network configured to provide voice, data, messaging, authorization and authentication, applications, and/or Voice Over Internet Protocol (VoIP) services to one or more of the WTRUs102. For example, the core network106/107/109may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, packet data network connectivity, Ethernet connectivity, video distribution, etc., and/or perform high-level security functions, such as user authentication.

Although not shown inFIG.1A, it will be appreciated that the RAN103/104/105and/or RAN103b/104b/105band/or the core network106/107/109may be in direct or indirect communication with other RANs that employ the same RAT as the RAN103/104/105and/or RAN103b/104b/105bor a different RAT. For example, in addition to being connected to the RAN103/104/105and/or RAN103b/104b/105b, which may be utilizing an E-UTRA radio technology, the core network106/107/109may also be in communication with another RAN (not shown) employing a GSM or NR radio technology.

The core network106/107/109may also serve as a gateway for the WTRUs102to access the PSTN108, the Internet110, and/or other networks112. The PSTN108may include circuit-switched telephone networks that provide Plain Old Telephone Service (POTS). The Internet110may include a global system of interconnected computer networks and devices that use common communication protocols, such as the Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and the Internet Protocol (IP) in the TCP/IP Internet Protocol suite. The other networks112may include wired or wireless communications networks owned and/or operated by other service providers. For example, the networks112may include any type of packet data network (e.g., an IEEE 802.3 Ethernet network) or another core network connected to one or more RANs, which may employ the same RAT as the RAN103/104/105and/or RAN103b/104b/105bor a different RAT.

Some or all of the WTRUs102a,102b,102c,102d,102e, and102fin the communications system100may include multi-mode capabilities, e.g., the WTRUs102a,102b,102c,102d,102e, and102fmay include multiple transceivers for communicating with different wireless networks over different wireless links. For example, the WTRU102gshown inFIG.1Amay be configured to communicate with the base station114a, which may employ a cellular-based radio technology, and with the base station114c, which may employ an IEEE 802 radio technology.

Although not shown inFIG.1A, it will be appreciated that a User Equipment may make a wired connection to a gateway. The gateway may be a Residential Gateway (RG). The RG may provide connectivity to a Core Network106/107/109. It will be appreciated that many of the ideas contained herein may equally apply to UEs that are WTRUs and UEs that use a wired connection to connect to a network. For example, the ideas that apply to the wireless interfaces115,116,117and115c/116c/117cmay equally apply to a wired connection.

FIG.1Bis a system diagram of an example RAN103and core network106. As noted above, the RAN103may employ a UTRA radio technology to communicate with the WTRUs102a,102b, and102cover the air interface115. The RAN103may also be in communication with the core network106. As shown inFIG.1B, the RAN103may include Node-Bs140a,140b, and140c, which may each include one or more transceivers for communicating with the WTRUs102a,102b, and102cover the air interface115. The Node-Bs140a,140b, and140cmay each be associated with a particular cell (not shown) within the RAN103. The RAN103may also include RNCs142a,142b. It will be appreciated that the RAN103may include any number of Node-Bs and Radio Network Controllers (RNCs.)

As shown inFIG.1B, the Node-Bs140a,140bmay be in communication with the RNC142a. Additionally, the Node-B140cmay be in communication with the RNC142b. The Node-Bs140a,140b, and140cmay communicate with the respective RNCs142aand142bvia an Iub interface. The RNCs142aand142bmay be in communication with one another via an Iur interface. Each of the RNCs142aand142bmay be configured to control the respective Node-Bs140a,140b, and140cto which it is connected. In addition, each of the RNCs142aand142bmay be configured to carry out or support other functionality, such as outer loop power control, load control, admission control, packet scheduling, handover control, macro-diversity, security functions, data encryption, and the like.

The core network106shown inFIG.1Bmay include a media gateway (MGW)144, a Mobile Switching Center (MSC)146, a Serving GPRS Support Node (SGSN)148, and/or a Gateway GPRS Support Node (GGSN)150. While each of the foregoing elements are depicted as part of the core network106, it will be appreciated that any one of these elements may be owned and/or operated by an entity other than the core network operator.

The RNC142ain the RAN103may be connected to the MSC146in the core network106via an IuCS interface. The MSC146may be connected to the MGW144. The MSC146and the MGW144may provide the WTRUs102a,102b, and102cwith access to circuit-switched networks, such as the PSTN108, to facilitate communications between the WTRUs102a,102b, and102c, and traditional land-line communications devices.

The RNC142ain the RAN103may also be connected to the SGSN148in the core network106via an IuPS interface. The SGSN148may be connected to the GGSN150. The SGSN148and the GGSN150may provide the WTRUs102a,102b, and102cwith access to packet-switched networks, such as the Internet110, to facilitate communications between and the WTRUs102a,102b, and102c, and IP-enabled devices.

The core network106may also be connected to the other networks112, which may include other wired or wireless networks that are owned and/or operated by other service providers.

FIG.1Cis a system diagram of an example RAN104and core network107. As noted above, the RAN104may employ an E-UTRA radio technology to communicate with the WTRUs102a,102b, and102cover the air interface116. The RAN104may also be in communication with the core network107.

The RAN104may include eNode-Bs160a,160b, and160c, though it will be appreciated that the RAN104may include any number of eNode-Bs. The eNode-Bs160a,160b, and160cmay each include one or more transceivers for communicating with the WTRUs102a,102b, and102cover the air interface116. For example, the eNode-Bs160a,160b, and160cmay implement MIMO technology. Thus, the eNode-B160a, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU102a.

Each of the eNode-Bs160a,160b, and160cmay be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the uplink and/or downlink, and the like. As shown inFIG.1C, the eNode-Bs160a,160b, and160cmay communicate with one another over an X2 interface.

The core network107shown inFIG.1Cmay include a Mobility Management Gateway (MME)162, a serving gateway164, and a Packet Data Network (PDN) gateway166. While each of the foregoing elements are depicted as part of the core network107, it will be appreciated that any one of these elements may be owned and/or operated by an entity other than the core network operator.

The MME162may be connected to each of the eNode-Bs160a,160b, and160cin the RAN104via an S1 interface and may serve as a control node. For example, the MME162may be responsible for authenticating users of the WTRUs102a,102b, and102c, bearer activation/deactivation, selecting a particular serving gateway during an initial attach of the WTRUs102a,102b, and102c, and the like. The MME162may also provide a control plane function for switching between the RAN104and other RANs (not shown) that employ other radio technologies, such as GSM or WCDMA.

The serving gateway164may be connected to each of the eNode-Bs160a,160b, and160cin the RAN104via the S1 interface. The serving gateway164may generally route and forward user data packets to/from the WTRUs102a,102b, and102c. The serving gateway164may also perform other functions, such as anchoring user planes during inter-eNode B handovers, triggering paging when downlink data is available for the WTRUs102a,102b, and102c, managing and storing contexts of the WTRUs102a,102b, and102c, and the like.

The serving gateway164may also be connected to the PDN gateway166, which may provide the WTRUs102a,102b, and102cwith access to packet-switched networks, such as the Internet110, to facilitate communications between the WTRUs102a,102b,102c, and IP-enabled devices.

The core network107may facilitate communications with other networks. For example, the core network107may provide the WTRUs102a,102b, and102cwith access to circuit-switched networks, such as the PSTN108, to facilitate communications between the WTRUs102a,102b, and102cand traditional land-line communications devices. For example, the core network107may include, or may communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the core network107and the PSTN108. In addition, the core network107may provide the WTRUs102a,102b, and102cwith access to the networks112, which may include other wired or wireless networks that are owned and/or operated by other service providers.

FIG.1Dis a system diagram of an example RAN105and core network109. The RAN105may employ an NR radio technology to communicate with the WTRUs102aand102bover the air interface117. The RAN105may also be in communication with the core network109. A Non-3GPP Interworking Function (N3IWF)199may employ a non-3GPP radio technology to communicate with the WTRU102cover the air interface198. The N3IWF199may also be in communication with the core network109.

The RAN105may include gNode-Bs180aand180b. It will be appreciated that the RAN105may include any number of gNode-Bs. The gNode-Bs180aand180bmay each include one or more transceivers for communicating with the WTRUs102aand102bover the air interface117. When integrated access and backhaul connection are used, the same air interface may be used between the WTRUs and gNode-Bs, which may be the core network109via one or multiple gNBs. The gNode-Bs180aand180bmay implement MIMO, MU-MIMO, and/or digital beamforming technology. Thus, the gNode-B180a, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU102a. It should be appreciated that the RAN105may employ of other types of base stations such as an eNode-B. It will also be appreciated the RAN105may employ more than one type of base station. For example, the RAN may employ eNode-Bs and gNode-Bs.

The N3IWF199may include a non-3GPP Access Point180c. It will be appreciated that the N3IWF199may include any number of non-3GPP Access Points. The non-3GPP Access Point180cmay include one or more transceivers for communicating with the WTRUs102cover the air interface198. The non-3GPP Access Point180cmay use the 802.11 protocol to communicate with the WTRU102cover the air interface198.

Each of the gNode-Bs180aand180bmay be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the uplink and/or downlink, and the like. As shown inFIG.1D, the gNode-Bs180aand180bmay communicate with one another over an Xn interface, for example.

The core network109shown inFIG.1Dmay be a 5G core network (5GC). The core network109may offer numerous communication services to customers who are interconnected by the radio access network. The core network109comprises a number of entities that perform the functionality of the core network. As used herein, the term “core network entity” or “network function” refers to any entity that performs one or more functionalities of a core network. It is understood that such core network entities may be logical entities that are implemented in the form of computer-executable instructions (software) stored in a memory of, and executing on a processor of, an apparatus configured for wireless and/or network communications or a computer system, such as system90illustrated inFigure x1G.

In the example ofFIG.1D, the 5G Core Network109may include an access and Access and Mobility Management Function (AMF)172, a Session Management Function (SMF)174, User Plane Functions (UPFs)176aand176b, a User Data Management Function (UDM)197, an Authentication Server Function (AUSF)190, a Network Exposure Function (NEF)196, a Policy Control Function (PCF)184, a Non-3GPP Interworking Function (N3IWF)199, a User Data Repository (UDR)178. While each of the foregoing elements are depicted as part of the 5G core network109, it will be appreciated that any one of these elements may be owned and/or operated by an entity other than the core network operator. It will also be appreciated that a 5G core network may not consist of all of these elements, may consist of additional elements, and may consist of multiple instances of each of these elements.FIG.1Dshows that network functions directly connect to one another, however, it should be appreciated that they may communicate via routing agents such as a diameter routing agent or message buses.

In the example ofFIG.1D, connectivity between network functions is achieved via a set of interfaces, or reference points. It will be appreciated that network functions could be modeled, described, or implemented as a set of services that are invoked, or called, by other network functions or services. Invocation of a Network Function service may be achieved via a direct connection between network functions, an exchange of messaging on a message bus, calling a software function, etc.

The AMF172may be connected to the RAN105via an N2 interface and may serve as a control node. For example, the AMF172may be responsible for registration management, connection management, reachability management, access authentication, and access authorization. The AMF may be responsible forwarding user plane tunnel configuration information to the RAN105via the N2 interface. The AMF172may receive the user plane tunnel configuration information from the SMF via an N11 interface. The AMF172may generally route and forward NAS packets to/from the WTRUs102a,102b, and102cvia an N1 interface. The N1 interface is not shown inFIG.1D.

The SMF174may be connected to the AMF172via an N11 interface. Similarly, the SMF may be connected to the PCF184via an N7 interface, and to the UPFs176aand176bvia an N4 interface. The SMF174may serve as a control node. For example, the SMF174may be responsible for Session Management, IP address allocation for the WTRUs102a,102b, and102c, management and configuration of traffic steering rules in the UPF176aand UPF176b, and generation of downlink data notifications to the AMF172.

The UPF176aand UPF176bmay provide the WTRUs102a,102b, and102cwith access to a Packet Data Network (PDN), such as the Internet110, to facilitate communications between the WTRUs102a,102b, and102cand other devices. The UPF176aand UPF176bmay also provide the WTRUs102a,102b, and102cwith access to other types of packet data networks. For example, Other Networks112may be Ethernet Networks or any type of network that exchanges packets of data. The UPF176aand UPF176bmay receive traffic steering rules from the SMF174via the N4 interface. The UPF176aand UPF176bmay provide access to a packet data network by connecting a packet data network with an N6 interface or by connecting to each other and to other UPFs via an N9 interface. In addition to providing access to packet data networks, the UPF176may be responsible packet routing and forwarding, policy rule enforcement, quality of service handling for user plane traffic, downlink packet buffering.

The AMF172may also be connected to the N3IWF199, for example, via an N2 interface. The N3IWF facilitates a connection between the WTRU102cand the 5G core network170, for example, via radio interface technologies that are not defined by 3GPP. The AMF may interact with the N3IWF199in the same, or similar, manner that it interacts with the RAN105.

The PCF184may be connected to the SMF174via an N7 interface, connected to the AMF172via an N15 interface, and to an Application Function (AF)188via an N5 interface. The N15 and N5 interfaces are not shown inFIG.1D. The PCF184may provide policy rules to control plane nodes such as the AMF172and SMF174, allowing the control plane nodes to enforce these rules. The PCF184may send policies to the AMF172for the WTRUs102a,102b, and102cso that the AMF may deliver the policies to the WTRUs102a,102b, and102cvia an N1 interface. Policies may then be enforced, or applied, at the WTRUs102a,102b, and102c.

The UDR178may act as a repository for authentication credentials and subscription information. The UDR may connect to network functions, so that network function can add to, read from, and modify the data that is in the repository. For example, the UDR178may connect to the PCF184via an N36 interface. Similarly, the UDR178may connect to the NEF196via an N37 interface, and the UDR178may connect to the UDM197via an N35 interface.

The UDM197may serve as an interface between the UDR178and other network functions. The UDM197may authorize network functions to access of the UDR178. For example, the UDM197may connect to the AMF172via an N8 interface, the UDM197may connect to the SMF174via an N10 interface. Similarly, the UDM197may connect to the AUSF190via an N13 interface. The UDR178and UDM197may be tightly integrated.

The AUSF190performs authentication related operations and connects to the UDM178via an N13 interface and to the AMF172via an N12 interface.

The NEF196exposes capabilities and services in the 5G core network109to Application Functions (AF)188. Exposure may occur on the N33 API interface. The NEF may connect to an AF188via an N33 interface and it may connect to other network functions in order to expose the capabilities and services of the 5G core network109.

Application Functions188may interact with network functions in the 5G Core Network109. Interaction between the Application Functions188and network functions may be via a direct interface or may occur via the NEF196. The Application Functions188may be considered part of the 5G Core Network109or may be external to the 5G Core Network109and deployed by enterprises that have a business relationship with the mobile network operator.

Network Slicing is a mechanism that could be used by mobile network operators to support one or more ‘virtual’ core networks behind the operator's air interface. This involves ‘slicing’ the core network into one or more virtual networks to support different RANs or different service types running across a single RAN. Network slicing enables the operator to create networks customized to provide optimized solutions for different market scenarios which demands diverse requirements, e.g. in the areas of functionality, performance and isolation.

3GPP has designed the 5G core network to support Network Slicing. Network Slicing is a good tool that network operators can use to support the diverse set of 5G use cases (e.g., massive IoT, critical communications, V2X, and enhanced mobile broadband) which demand very diverse and sometimes extreme requirements. Without the use of network slicing techniques, it is likely that the network architecture would not be flexible and scalable enough to efficiently support a wider range of use cases need when each use case has its own specific set of performance, scalability, and availability requirements. Furthermore, introduction of new network services should be made more efficient.

Referring again toFIG.1D, in a network slicing scenario, a WTRU102a,102b, or102cmay connect to an AMF172, via an N1 interface. The AMF may be logically part of one or more slices. The AMF may coordinate the connection or communication of WTRU102a,102b, or102cwith one or more UPF176aand176b, SMF174, and other network functions. Each of the UPFs176aand176b, SMF174, and other network functions may be part of the same slice or different slices. When they are part of different slices, they may be isolated from each other in the sense that they may utilize different computing resources, security credentials, etc.

The core network109may facilitate communications with other networks. For example, the core network109may include, or may communicate with, an IP gateway, such as an IP Multimedia Subsystem (IMS) server, that serves as an interface between the 5G core network109and a PSTN108. For example, the core network109may include, or communicate with a short message service (SMS) service center that facilities communication via the short message service. For example, the 5G core network109may facilitate the exchange of non-IP data packets between the WTRUs102a,102b, and102cand servers or applications functions188. In addition, the core network170may provide the WTRUs102a,102b, and102cwith access to the networks112, which may include other wired or wireless networks that are owned and/or operated by other service providers.

The core network entities described herein and illustrated inFIGS.1A,1C,1D, and1Eare identified by the names given to those entities in certain existing 3GPP specifications, but it is understood that in the future those entities and functionalities may be identified by other names and certain entities or functions may be combined in future specifications published by 3GPP, including future 3GPP NR specifications. Thus, the particular network entities and functionalities described and illustrated inFIGS.1A,1B,1C,1D, and1Eare provided by way of example only, and it is understood that the subject matter disclosed and claimed herein may be embodied or implemented in any similar communication system, whether presently defined or defined in the future.

FIG.1Eillustrates an example communications system111in which the systems, methods, apparatuses described herein may be used. Communications system111may include Wireless Transmit/Receive Units (WTRUs) A, B, C, D, E, F, a base station gNB121, a V2X server124, and Roadside Units (RSUs)123aand123b. In practice, the concepts presented herein may be applied to any number of WTRUs, base station gNBs, V2X networks, and/or other network elements. One or several or all WTRUs A, B, C, D, E, and F may be out of range of the access network coverage131. WTRUs A, B, and C form a V2X group, among which WTRU A is the group lead and WTRUs B and C are group members.

WTRUs A, B, C, D, E, and F may communicate with each other over a Uu interface129via the gNB121if they are within the access network coverage131. In the example ofFIG.1E, WTRUs B and F are shown within access network coverage131. WTRUs A, B, C, D, E, and F may communicate with each other directly via a Sidelink interface (e.g., PC5 or NR PC5) such as interface125a,125b, or128, whether they are under the access network coverage131or out of the access network coverage131. For instance, in the example ofFIG.1E, WRTU D, which is outside of the access network coverage131, communicates with WTRU F, which is inside the coverage131.

WTRUs A, B, C, D, E, and F may communicate with RSU123aor123bvia a Vehicle-to-Network (V2N)133or Sidelink interface125b. WTRUs A, B, C, D, E, and F may communicate to a V2X Server124via a Vehicle-to-Infrastructure (V2I) interface127. WTRUs A, B, C, D, E, and F may communicate to another UE via a Vehicle-to-Person (V2P) interface128.

FIG.1Fis a block diagram of an example apparatus or device WTRU102that may be configured for wireless communications and operations in accordance with the systems, methods, and apparatuses described herein, such as a WTRU102ofFIG.1A,1B,1C,1D, or1E. As shown inFIG.1F, the example WTRU102may include a processor118, a transceiver120, a transmit/receive element122, a speaker/microphone124, a keypad126, a display/touchpad/indicators128, non-removable memory130, removable memory132, a power source134, a global positioning system (GPS) chipset136, and other peripherals138. It will be appreciated that the WTRU102may include any sub-combination of the foregoing elements. Also, the base stations114aand114b, and/or the nodes that base stations114aand114bmay represent, such as but not limited to transceiver station (BTS), a Node-B, a site controller, an access point (AP), a home node-B, an evolved home node-B (eNodeB), a home evolved node-B (HeNB), a home evolved node-B gateway, a next generation node-B (gNode-B), and proxy nodes, among others, may include some or all of the elements depicted inFIG.1Fand described herein.

The processor118may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Array (FPGAs) circuits, any other type of integrated circuit (IC), a state machine, and the like. The processor118may perform signal coding, data processing, power control, input/output processing, and/or any other functionality that enables the WTRU102to operate in a wireless environment. The processor118may be coupled to the transceiver120, which may be coupled to the transmit/receive element122. WhileFIG.1Fdepicts the processor118and the transceiver120as separate components, it will be appreciated that the processor118and the transceiver120may be integrated together in an electronic package or chip.

The transmit/receive element122of a UE may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station114aofFIG.1A) over the air interface115/116/117or another UE over the air interface115d/116d/117d. For example, the transmit/receive element122may be an antenna configured to transmit and/or receive RF signals. The transmit/receive element122may be an emitter/detector configured to transmit and/or receive IR, UV, or visible light signals, for example. The transmit/receive element122may be configured to transmit and receive both RF and light signals. It will be appreciated that the transmit/receive element122may be configured to transmit and/or receive any combination of wireless or wired signals.

In addition, although the transmit/receive element122is depicted inFIG.1Fas a single element, the WTRU102may include any number of transmit/receive elements122. More specifically, the WTRU102may employ MIMO technology. Thus, the WTRU102may include two or more transmit/receive elements122(e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface115/116/117.

The transceiver120may be configured to modulate the signals that are to be transmitted by the transmit/receive element122and to demodulate the signals that are received by the transmit/receive element122. As noted above, the WTRU102may have multi-mode capabilities. Thus, the transceiver120may include multiple transceivers for enabling the WTRU102to communicate via multiple RATs, for example NR and IEEE 802.11 or NR and E-UTRA, or to communicate with the same RAT via multiple beams to different RRHs, TRPs, RSUs, or nodes.

The processor118of the WTRU102may be coupled to, and may receive user input data from, the speaker/microphone124, the keypad126, and/or the display/touchpad/indicators128(e.g., a liquid crystal display (LCD)) display unit or organic light-emitting diode (OLED) display unit. The processor118may also output user data to the speaker/microphone124, the keypad126, and/or the display/touchpad/indicators128. In addition, the processor118may access information from, and store data in, any type of suitable memory, such as the non-removable memory130and/or the removable memory132. The non-removable memory130may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory132may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. The processor118may access information from, and store data in, memory that is not physically located on the WTRU102, such as on a server that is hosted in the cloud or in an edge computing platform or in a home computer (not shown).

The processor118may receive power from the power source134and may be configured to distribute and/or control the power to the other components in the WTRU102. The power source134may be any suitable device for powering the WTRU102. For example, the power source134may include one or more dry cell batteries, solar cells, fuel cells, and the like.

The processor118may also be coupled to the GPS chipset136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU102. In addition to, or in lieu of, the information from the GPS chipset136, the WTRU102may receive location information over the air interface115/116/117from a base station (e.g., base stations114a,114b) and/or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU102may acquire location information by way of any suitable location-determination method.

The processor118may further be coupled to other peripherals138, which may include one or more software and/or hardware modules that provide additional features, functionality, and/or wired or wireless connectivity. For example, the peripherals138may include various sensors such as an accelerometer, biometrics (e.g., finger print) sensors, an e-compass, a satellite transceiver, a digital camera (for photographs or video), a universal serial bus (USB) port or other interconnect interfaces, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, and the like.

The WTRU102may be included in other apparatuses or devices, such as a sensor, consumer electronics, a wearable device such as a smart watch or smart clothing, a medical or eHealth device, a robot, industrial equipment, a drone, a vehicle such as a car, truck, train, or an airplane. The WTRU102may connect to other components, modules, or systems of such apparatuses or devices via one or more interconnect interfaces, such as an interconnect interface that may comprise one of the peripherals138.

FIG.1Gis a block diagram of an exemplary computing system90in which one or more apparatuses of the communications networks illustrated inFIGS.1A,1C,1D, and1Emay be embodied, such as certain nodes or functional entities in the RAN103/104/105, Core Network106/107/109, PSTN108, Internet110, Other Networks112, or Network Services113. Computing system90may comprise a computer or server and may be controlled primarily by computer readable instructions, which may be in the form of software, wherever, or by whatever means such software is stored or accessed. Such computer readable instructions may be executed within a processor91, to cause computing system90to do work. The processor91may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Array (FPGAs) circuits, any other type of integrated circuit (IC), a state machine, and the like. The processor91may perform signal coding, data processing, power control, input/output processing, and/or any other functionality that enables the computing system90to operate in a communications network. Coprocessor81is an optional processor, distinct from main processor91, that may perform additional functions or assist processor91. Processor91and/or coprocessor81may receive, generate, and process data related to the methods and apparatuses disclosed herein.

In operation, processor91fetches, decodes, and executes instructions, and transfers information to and from other resources via the computing system's main data-transfer path, system bus80. Such a system bus connects the components in computing system90and defines the medium for data exchange. System bus80typically includes data lines for sending data, address lines for sending addresses, and control lines for sending interrupts and for operating the system bus. An example of such a system bus80is the PCI (Peripheral Component Interconnect) bus.

Memories coupled to system bus80include random access memory (RAM)82and read only memory (ROM)93. Such memories include circuitry that allows information to be stored and retrieved. ROMs93generally contain stored data that cannot easily be modified. Data stored in RAM82may be read or changed by processor91or other hardware devices. Access to RAM82and/or ROM93may be controlled by memory controller92. Memory controller92may provide an address translation function that translates virtual addresses into physical addresses as instructions are executed. Memory controller92may also provide a memory protection function that isolates processes within the system and isolates system processes from user processes. Thus, a program running in a first mode may access only memory mapped by its own process virtual address space; it cannot access memory within another process's virtual address space unless memory sharing between the processes has been set up.

In addition, computing system90may contain peripherals controller83responsible for communicating instructions from processor91to peripherals, such as printer94, keyboard84, mouse95, and disk drive85.

Display86, which is controlled by display controller96, is used to display visual output generated by computing system90. Such visual output may include text, graphics, animated graphics, and video. The visual output may be provided in the form of a graphical user interface (GUI). Display86may be implemented with a CRT-based video display, an LCD-based flat-panel display, gas plasma-based flat-panel display, or a touch-panel. Display controller96includes electronic components required to generate a video signal that is sent to display86.

Further, computing system90may contain communication circuitry, such as for example a wireless or wired network adapter97, that may be used to connect computing system90to an external communications network or devices, such as the RAN103/104/105, Core Network106/107/109, PSTN108, Internet110, WTRUs102, or Other Networks112ofFIGS.1A,1B,1C,1D, and1E, to enable the computing system90to communicate with other nodes or functional entities of those networks. The communication circuitry, alone or in combination with the processor91, may be used to perform the transmitting and receiving steps of certain apparatuses, nodes, or functional entities described herein.

It is understood that any or all of the apparatuses, systems, methods, and processes described herein may be embodied in the form of computer executable instructions (e.g., program code) stored on a computer-readable storage medium which instructions, when executed by a processor, such as processors118or91, cause the processor to perform and/or implement the systems, methods and processes described herein. Specifically, any of the steps, operations, or functions described herein may be implemented in the form of such computer executable instructions, executing on the processor of an apparatus or computing system configured for wireless and/or wired network communications. Computer readable storage media includes volatile and nonvolatile, removable and non-removable media implemented in any non-transitory (e.g., tangible or physical) method or technology for storage of information, but such computer readable storage media do not include signals. Computer readable storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other tangible or physical medium which may be used to store the desired information and which may be accessed by a computing system.

PC5 Reference Point

The V2X communication over PC5 reference point is a type of ProSe Direct Communication where the V2X communication over PC5 reference point is connectionless, and there is no signaling over PC5 control plane for connection establishment. V2X messages are exchanged between UEs over PC5 user plane.

NR V2X Sidelink Use Case

In NR V2X, Vehicles Platooning enables the vehicles to form a group traveling together dynamically. All the vehicles in the platoon receive periodic data from the leading vehicle to carry on platoon operations. This information allows the distance between vehicles to become extremely small, e.g., the gap distance translated to time can be very low (sub-second). Platooning applications may allow the vehicles following to be autonomously driven. In TS 22.186, it is stated that for vehicle platooning, the 3GPP system shall be able to support reliable V2V communications between a specific UE supporting V2X applications and up to 19 other UEs supporting V2X applications. This requires extended UE-to-UE communication range. UE-to-UE relay can help to provide reliable V2V communications in the long platoon (see 3GPP TS 22.186, Enhancement of 3GPP support for V2X scenarios; Stage 1 (Release 15), V16.0.0).

In V2X, application on vehicles can form a group in the proximity, and each member may groupcast application data to other members in the group. In TS 22.886, it is stated that for data sharing use cases, the 3GPP system shall be able to support less than 10 ms latency message and reliability of 90% between V2X applications (see 3GPP TR 22.886, Study on enhancement of 3GPP Support for 5GV2X Services; (Release 15), V15.1.0).

NR Device-to-Device Sidelink Use case

In NR, UEs in an indoor environment may have coverage problem due to penetration loss or shadowing. Therefore, a special cooperative UE (CUE) could be installed outdoor and has more advanced transmit/reception capability than a normal UE. The CUE and indoor UE(s) could form UE group, and the CUE helps with the indoor target UE (TUE) to improve DL/UL performance by relaying their data on SL. For example, when a gNB broadcast/multicast message to all UEs in the group, the gNB can send the message to CUE and the CUE can broadcast/multicast to all UEs in the group.

In NR, Smartphones or new forms of 5G portable devices (e.g., VR/AR devices, robot, etc.) can form a group for entertainment and education (e.g., interactive gaming or conferences) over PC5 interface. For example, in a gaming group, a group member interacts with all other group members with low End-to-End latency and high data rate.

Example Challenges

As discussed above, a group may be managed by the upper layer, e.g. the V2X layer or applications. Therefore, the group context information may not be visible to RAN/AS layer or may have only limited information visible such as the ID of group members. However, without AS level group context information, the AS may not be able to support the diverse and stringent Sidelink QoS requirement for upper layer groupcast as described in the following examples.

Limited groupcast range: Without the AS topology information, AS layer groupcast is limited to one AS level hop. Note in this disclosure, we assume there is no PHY layer relay. Therefore, a AS level hop is the same as a PHY layer hop. However, the Upper Layer Group (ULG) may be beyond one AS level hop. Therefore, AS layer groupcast may not be able to deliver a groupcast message to all members in the group or within a service range that is bigger than one AS level hop. For example, in V2X vehicle platooning with up to 19 UEs, the platoon lead and the vehicle at the edge may be located within one hop communication range. Therefore, without AS level group management to manage the topology of the group and configure relays, the platoon lead cannot groupcast a message to all members of the group.

Cannot Fulfill QoS requirements: The upper layer usually forms a group that does not consider the AS context information. Therefore, without AS management of ULG, the groupcast message cannot be delivered to meet the stringent QoS requirement. For example, antenna arrays are supported in NR, a UE may use different communication modes to transmit a message at AS layer with different transmission range. A UE can broadcast/multicast a message to all receivers in all directions within a short-range using a (quasi)omni directional antenna pattern. On the other hand, a UE can unicast a message to receivers in a cone with a specific direction but within a longer range. If the AS layer uses broadcast/multicast to transmit a groupcast message, a group member cannot receive it if the group member is out of the transmission range. On the other hand, if the AS layer uses unicast to transmit a message, it needs to transmit it multiple times since group members may not be in the same cone. Therefore, without AS layer distance and direction information, the AS cannot decide which transmission mode to use to transmit a groupcast message from the upper layer. By obtaining the AS context information, AS can know the group members that are in the multicast range and unicast range. AS can deliver the groupcast message to group members in the multicast range via a multicast transmission and to group members in the unicast range via several unicast transmissions. This can reduce the latency and guarantee the reliability to transmit an upper layer groupcast message. Therefore, it is helpful for AS has group management capability by dividing an ULG into several AS subgroups based on AS context to enhance the performance of a groupcast transmission.

Moreover, the existing layer 2 protocol structure cannot support some new groupcast features in NR. For example, the existing layer 2 protocol structure cannot support both groupcast feedback options and decide which feedback option to use. In another example, the existing layer 2 protocol structure cannot support multiple transmission modes to transmit a groupcast message. If a group member fails to receive a groupcast message via multicast when it moves out of multicast transmission range, layer 2 cannot dynamically retransmit the groupcast message to the UE via unicast.

Disclosed herein are methods and systems for NR Sidelink AS group management and bearer management to enhance Sidelink Groupcast communications.

A Sidelink AS group management function is disclosed for a UE to discover group members and organize them into AS layer sub-groups based on the AS layer group context information.

A centralized Sidelink AS group management is disclosed that the Sidelink AS Group Manager discovers group members and organizes them into AS layer sub-groups for a UE. Two discovery procedures are disclosed that Sidelink AS Group Manager discovers group members and their AS context information via exchanging control messages. A passive discovery procedure is disclosed that a UE sends AS group context information to the SL AS Group Manager via AS Group Context Report. An active discovery procedure is disclosed that SL AS Group Manager sends an AS Group Context Request message to all UEs within a service range. A Subgroup formation and configuration procedure is disclosed that SL AS Group Manager organizes the ULG into AS layer sub-groups, configures UE-to-UE relays for each UE in the ULG and sends the AS group management information to the UE.

A distributed Sidelink AS group management method is disclosed that each UE discovers its group members and organizes the ULG into AS layer sub-groups. Two distributed AS group discovery procedures are disclosed that a UE discovers group members and obtains their AS context information. A proactive discovery procedure is disclosed that each UE periodically sends its AS group context information to all UE within a service range. A reactive discovery procedure is disclosed that a UE sends discovery requests to and receives discovery response from all UEs within the service range to obtain AS group context information. A Subgroup formation and configuration procedure is disclosed a UE organizes the ULG into AS layer subgroups and configures UE-to-UE relays.

New Layer 2 structures and procedures are disclosed to enhance bearer management for Sidelink groupcast communications. In the first disclosed structure and procedure, SDAP entity divides the group into subgroups based on the QoS requirement of the groupcast message. Each subgroup has its own layer 2 destination ID and packets associated with different subgroups have separated radio bears. In the second disclosed structure and procedure, PDCP entity makes the duplications of PDCP PDU based on the number of subgroups and sends the PDU destined to different subgroups to different RLCs. In the third disclosed structure and procedure, the RLC entity makes the duplications of RLC PDU based on the number of subgroups and sends the PDU with different transmission mode to different Logical Channels. In the fourth disclosed structure and procedure, MAC entity makes the duplications of MAC PDU based on the number of subgroups and sends the PDU with different transmission mode to different HARQ entities. In the fifth disclosed structure and procedure, MAC entity makes the duplications of MAC PDU based on the number of subgroups and sends the PDU with different transmission mode with different HARQ processes.

Example of the Four Devices

For example, a number of concepts described herein can be described in terms of five devices: a first device which is a transmitter; a second device that configures the first device; a third device that is downstream or upstream from the first device and uses it a relay; a fourth device which is an AS group manager.

The first device includes stored instructions which cause the first device to receive a groupcast packet, receive information about a first group of devices for the transmission of the groupcast packet, perform mapping of the first group of devices to one or more second groups of devices, select a second group of devices, and transmit the groupcast packet to the second groups of devices.

The first device may be configured by the second device, which sends information such as: an AS ID of the transmitter; an upper layer ID of an Upper Layer Group (ULG) to which the transmitter belongs; an AS ID associated with the ULG; and a capability of the transmitter to forward control plane and user plane packet to a third device within a range.

The second device may be a base station, RSU, another UE, Core Network node or combination of such devices.

The first device may be preconfigured, e.g., as specified by standards or otherwise provided, with such parameters as: an AS ID of the first device; an Upper Layer ID of the ULG; an AS ID associated with the ULG; and the capability of the first device to forward control plane and user plane packet to a third device within a range.

The first device may receive the groupcast packet from the upper layer of the first device or from the upstream device.

The first device may receive information about the first group of devices from the upper layer of the first device, and the first group of devices may be a group of upper layer devices. The information may include an ULG ID, QoS requirement, group size, or member ID in the group.

The first device may check whether a mapping rule exists to fulfill the ULG groupcast requirement based on current AS context information.

The first device may perform an AS group management procedure to generate one or more mapping rules. In doing so, the first device may send a group management request to the AS group manager.

The AS group manager may receive AS group context information via one or more AS group context report messages, where the group context report message contains information listed in Table 2, such as an AS ID of the reporting UE, an AS ID of the group manager, a sequence number, a position, a maximum number of forwarding, maximum forward physical range, AS group context information, AS IDs of relay UEs traversed, and capability of a relay UE traversed, wherein the AS group context information includes items such as AS group IDs, relay capability, AS group context information of neighbors. The AS group manager may then send an AS Group Context report response which contains the AS ID of each relay device on the path.

The AS group manager may send an AS group context request message to all devices within a service range periodically or receive a group management request message from another device in the network.

The AS group manager may generate mapping rules, and may configure relays for devices and send the AS subgroup configuration information to a UE via dedicated control messages, wherein the message contains AS Group Management Information listed in Table 6, such as ULG member, Path to ULG member and Management Information of AS subgroup Group listed in Table 7.

When the first device sends a group management request and AS Group Context Report messages to the AS group manager, where the group context report message contains information such as that listed in Table 2. The first device may then receive a Group Context Report response from the AS group manager containing an AS ID of each relay device on the path.

The first device may perform a distributed group management procedure that includes: sending AS group context information to all devices within a service range via AS Group Context Advertisement messages; sending discovery requests to, and receives discovery response from, all devices within the service range to obtain AS group context information; generating mapping rule, configuring relays for devices and sends the AS subgroup configuration information to the UE via dedicated control messages; and send groupcast data message to each subgroup of the ULG.

The first device may determine whether to execute the mapping. For example, the first device may determine whether to execute the mapping based on information contained in a control message and a capability of the first device to forward control plane and user plane packets.

The first device may determine whether to execute the mapping based on information contained in a packet containing a data message and a configuration received from another device.

The first device may select a second group of devices using information contained the packet message and a configuration received from another device.

The first device may select a transmission method based on properties of the second group, such as distances between devices in the group and the number of devices in the group.

The first device may allocate resources for the transmission based on the selected transmission method.

The first device may select a HARQ method based on the properties of the second group. In doing so, the first device may indicate which devices of the second group should send back an acknowledgement, or a negative acknowledgement upon failing to receive the packet.

Architecture and Overview

In this section, an SL AS group management framework is disclosed to support a UE to transmit an upper layer groupcast message, which has diverse and stringent Sidelink QoS requirement, to all group members within a service range that may be bigger than one hop. The SL AS group management framework includes SL group management functions in the control plane and SL groupcast bearer management in the user plane.

FIG.2shows an example of topology to illustrate the disclosed framework. InFIG.2, UE 2, 4, 6, 7, and 8 are in the same Upper Layer Group (ULG), e.g., ULG 1. UE 2 receives an upper layer groupcast message and intends to transmit it to all UEs in ULG 1. There may be an RSU, gNB or scheduling UE in the network. There are also some UEs which support layer 2 or layer 3 relay function as UE 3 and UE 5 shown inFIG.2.

SL AS Group Management Function

The SL AS group management function is disclosed for a UE to discover group members and organize them into AS layer sub-groups based on the AS layer group context information. The SL AS group management function can be realized in the centralized and distributed approach. There are five AS function entities as shown inFIG.3. Note thatFIG.3is a simplified example of an illustration that each Node only has a single function entity. A Node can have multiple function entities at the same time. For example, a Node can be a User Plane relay node and a Receiver of a groupcast message. In another example, a Node can be a groupcast transmitter and AS Group Managers at the same time.

AS Group Manager: The AS Group Manager only exists in the centralized approach. The AS Group Manager discovers AS group context information of UEs within a service range. The SL AS Group Manager can be a gNB, RSU, Scheduling UE, or group lead assigned by the upper layer, or formed via local nodes coordination. The AS Group Manager may know the AS layer ID associated with the ULG, and a UE may know the AS layer ID of the AS Group Manager from the upper layer or network configuration. In the centralized approach, based on the obtained AS group context information, SL AS Group Manager organizes an ULG into AS layer sub-groups, configures UE-to-UE relays for each UE in the group and sends the AS group management configuration to the UE via dedicated control messages. Note that, the AS Group Manager may be or may not belonging to the ULG group.

Groupcast Transmitter (Tx): Groupcast Tx receives a groupcast message from the upper layer and sends the message to all members in the ULG within a service range. The Groupcast Transmitter knows the AS layer ID associated with group members, which is generated based on the ULG ID. In the distributed example, Groupcast Tx discovers its ULG members and their AS group context information via exchange control messages. Based on the obtained group members AS group context information, the UE organizes the ULG into AS layer sub-groups, configures UE-to-UE relays via dedicated control message.

Groupcast Receiver (Rx): The Groupcast Rx receives the groupcast message sent by Groupcast Tx and delivers it to the upper layer. The Groupcast Receiver knows the AS ID of the ULG, which is generated based on the ULG ID. Based on the radio distance from the transmitter, the Groupcast Rx may be (i) multicast Neighbor Rx which is within the multicast distance from Groupcast Transmitter, (ii) unicast Neighbor Rx which is within the unicast distance from the Groupcast Transmitter, and/or (iii) Non-neighbor Rx which is out of the one-hop communication distance from the Groupcast Tx but can be reached via one or multiple User Plane Relays.

Control Plane (CP) Relay: Control Plane (CP) Relay relays AS group management control message between its neighbor Nodes.

User Plane (UP) Relay: User Plane (UP) Relay relays AS groupcast data message between its neighbor Nodes. The UP Relay can be a layer 2 or layer 3 relay.

In the centralized approach as shown inFIG.4, the SL AS Group Manager discovers group members and their AS context information via exchanging control messages. Based on the obtained group members AS group context information, SL AS Group Manager organizes the ULG into AS layer sub-groups, configures UE-to-UE relays for each UE in the ULG and sends the AS group management information to the UE via dedicated control messages.

In the distributed approach as shown inFIG.6, each UE discovers its group members and their AS context information via exchanging control messages. Based on the obtained group members AS context information, the UE organizes the ULG into AS layer sub-groups, configures UE-to-UE relays via dedicated control message.

SL Groupcast Bearer Management

New Layer 2 structures are also disclosed to support multiple communication modes. In the first disclosed structure as shown inFIG.6, SDAP entity divides the group into subgroups based on the QoS requirement of the groupcast message. Each subgroup has its own layer 2 destination ID and packets associated with different subgroups have separated radio bears. In the second disclosed structure as shown inFIG.7, PDCP entity makes the duplications of PDCP PDU based on the number of subgroups and sends the PDU destined to different subgroups to different RLCs. In the third disclosed structure as shown inFIG.8, the RLC entity makes the duplications of RLC PDU based on the number of subgroups and sends the PDU with different transmission mode to different Logical Channels. For example, if the initial transmission using multicast fails, the RLC entity can retransmits the packet using unicast mode to each group member that does not receive the message. In the fourth disclosed structure as shown inFIG.9, MAC entity makes the duplications of MAC PDU based on the number of subgroups and sends the PDU with different transmission mode to different HARQ entities. In the fifth disclosed structure as shown inFIG.10, MAC entity makes the duplications of MAC PDU based on the number of subgroups and sends the PDU with different transmission mode with different HARQ processes.

SL Groupcast Overview

FIG.21shows an overall process that a UE receives a groupcast message from its upper layer which has diverse and stringent Sidelink QoS requirement, to all Upper Layer Group (ULG) members within a service range that may be bigger than one hop.FIG.22shows an overall process that a UE receives a groupcast message from another UE from its lower layer.

InFIG.21, the UE that receives a groupcast message from an upper layer which has diverse and stringent Sidelink QoS requirement, to all Upper layer Group (ULG) members within a service range that may be bigger than one hop. The UE check whether an AS subgroup exists to fulfill the ULG groupcast requirement based on current AS group context information. If not, the message triggers a centralized or distributed SL AS group management procedure in the control plane. The procedure discovers ULG members and their AS group context information, then organizes the ULG into AS layer sub-groups, configures UE-to-UE relays. The UE establishes SL groupcast bearer for all subgroups and transmit groupcast data message to members in each subgroup. The UE selects transmission method, allocates resources for the transmission resources for HARQ feedback. The detail description of Figure I is as follows.

At step1, a UE receives a groupcast message from its upper layer with ULG context information, e.g. ULG group size, group ID and service range.

At step2, based on the ULG context information, e.g. ULG group size, group ID and service range, the UE checks whether an AS group which may contain several AS subgroups is formed for the ULG group. If an AS group which may contains several subgroups is formed, the UE goes to step3a, otherwise, an AS group management process will be triggered to form a AS group which may contain several AS subgroups in step3b.

At step3a, the UE check whether the formed AS group can fulfill the QoS requirement and service range of the ULG groupcast message based on latest AS group context information in Table 1. If yes, the UE will transmit the message to each AS subgroups in step7. Otherwise, the UE triggers an AS group management process to form a new AS group which may contain several AS subgroups in step3b.

At step3b, the UE initiates a centralized or distributed SL AS group management procedure in the control plane, which discovers ULG members and their AS group context information, then organizes the ULG into AS layer sub-groups, configures UE-to-UE relays and establish groupcast bearer for each sub-groups. The UE goes to step4aif it uses centralized AS group management procedure and goes to step4bif it uses distributed AS group management procedure.

At step4a, the UE checks whether it is configured or enabled to serve as a AS group manager. If so, it discovers group members and their AS group context information as in step4b. Otherwise, the UE sends a AS group management request as described in Table 3 to the AS group manager to initiate the group management process.

At step4b, the UE discovers group member and their AS group context information listed in Table 1. If the UE is a AS group manager in the centralized SL AS group management procedure, the UE discovers group members and their AS context information using passive and active discovery procedures. In the passive discovery procedure described inFIG.11, UEs send AS group context information to the SL AS Group Manager. In the active discovery procedure described inFIG.12, the SL AS Group Manager pulls AS group context information from UEs within a service range. In the distributed SL AS group management procedure, the UE discovers its group members and their AS context information via exchanging control messages using proactive and reactive discovery procedures. In the proactive discovery procedure described inFIG.13, each UE periodically sends its AS group context information to all UEs within a service range. In the reactive discovery procedure described inFIG.14, a UE sends discovery requests to and receives discovery response from all UEs within the service range to obtain AS group context information.

At step5, the UE sends a AS group management request as described in Table 3 to the AS group manager to initiate the group management process.

At step6, based on the obtained AS context information during AS group context discovery, in the centralized procedure, SL AS Group Manager organizes the ULG into AS layer sub-groups, configures UE-to-UE relays for each UE and sends the AS subgroup configuration information to the UE to establish groupcast bearer via dedicated control messages. In the distributed procedure, the UE organizes the ULG into AS layer sub-groups, configures UE-to-UE relays for each UE and sends the AS subgroup configuration information to the UE to establish groupcast bearer via dedicated control messages.

At step7, after the AS group management procedure, the UE transmits groupcast data message to each subgroup members.

At step8, for each AS subgroup, the UE selects transmission method and allocates resource for the transmission and resource for HARQ feedback.

FIG.22shows an overall process that a UE receives a groupcast message from another UE from its lower layer. The detail descriptions ofFIG.22are described as follows.

At step1, a UE receives a message from another UE from its lower layer.

At step2, if the message is a groupcast data message, the UE further processes the message in step3a. If the message is a groupcast control message, the UE further processes the message in step3b.

At step3a, based on its AS group configuration, if the UE is a member in the AS subgroup the groupcast message destinated to, the UE will forward the message to its upper layer as in step4a. Otherwise, it decides whether to forward the message based on AS configuration.

At step3b, the UE processes the groupcast control message and may send a response to the originator of request which contains its AS group context information.

At step4a, the UE forwards the message to its upper layer.

At step4b, the UE decides whether to forward the message to its neighbors based on AS configuration. If so, it forwards the message to one or more neighbors in step5b, and discards the message otherwise in step6.

At step5a, the UE decides whether to forward the message based on AS subgroup configuration.

At step6, the UE discards the message.

At step7, the UE selects transmission method and allocates resource for the transmission and resources for the HARQ feedback.

SL AS Group Management

Centralized AS Group Management Procedures

In the centralized approach, the SL AS Group Manager discovers group members and their AS group context information via exchanging control messages. Based on the obtained group members AS group context information, SL AS Group Manager organizes the ULG into AS layer sub-groups, configures UE-to-UE relays for each UE in the group and send the AS group management configuration to the UE via dedicated control messages.

Centralized AS Group Discovery

In the centralized AS Group Management approach, an SL AS Group Manager discovers group members and their AS context information. Two centralized AS group discovery procedures, e.g., passive and active discovery procedures, are disclosed. In the passive discovery procedure, UEs send AS group context information to the SL AS Group Manager. In the active discovery procedure, the SL AS Group Manager pulls AS group context information from UEs within a service range. The AS group context information includes but is not limited to the fields show in Table 1. Note that a UE periodically exchanges AS layer messages with neighbors to obtain AS group context information of neighbors. The method about how a UE exchanges AS layer message with its neighbors is out of the scope of the disclosure.

TABLE 1AS group context informationNameDescriptionAS group IDsAS IDs associated with ULG the UE is belonging to. The ASID is generated based on the ULG ID. A UE may be a groupmember of multiple ULGs. Therefore, the UE may havemultiple AS IDs and each of them is associated to each ULG;Relay CapabilityThe capability of the UE to support CP Relay or UP Replayfor other UEs within the service range.AS group context information ofThis information may be obtained via periodicallyneighborsexchanging messages with Neighbors. The AS contextinformation of neighbors includes but not limited to thefollowing informationAS ID configured by the network or schedulingentity.AS IDs associated with ULG the UE is belonging to.Whether support CP Relay featureWhether support UP Relay featureAS link context information which includes thecommunication mode that can be used tocommunicate with the neighbor, e.g. multicast orunicast, the quality of the link.
Passive Discovery Procedure

In the passive discovery procedure, a UE has been pre-configured or configured an AS ID assigned by the network and the AS ID of the Group Manager is known. The method about how a UE is pre-configured or configured is out of the scope of the disclosure. In the passive discovery procedure, a UE sends AS group context information to the SL AS Group Manager via AS Group Context Report messages as shown inFIG.11. A UE may send AS Group Context Report message periodically based on a pre-configured or configured time interval, or when its AS group context information is changed as shown in step0. In the message, the UE may include but not limited to information shown in Table 2.

TABLE 2AS Group Context Report MessageFields nameDescriptionAS ID of the Reporting UEThe AS ID of the UE that reports the AS group contextinformation. The AS ID is configured by the network or ascheduling entity.AS ID of the Group ManagerThe AS ID of the AS Group Manager which is configured bythe network or scheduling entitySequence NumberThe sequence number generated by the reporting UE todifferentiate the AS Group Context Report message it sends.For example, the sequence number is increased by one foreach new AS Group Context Report message generated.PositionThe position of the UE, e.g. the GPS locationMaximum number of forwardingThe maximum number of times the AS Group ContextReport can be forwarded. This value is decreased by onewhen the AS Group Context Report is forwarded by a RelayUE. The AS Group Context Report message which containszero value of maximum forward time will be discarded.Maximum forward physical rangeThe maximum distance the AS Group Context Report can beforwarded. A Relay UE will not forward a AS GroupContext Report message originated from a reporting UE, ifthe distance to the reporting UE is bigger than the maximumforward range.AS group context informationAs described in Table 1AS IDs of Relay UEs traversedThe AS ID of each Relay UE the AS Group Context Reportmessage has traversed. Each Relay UE will append its AS IDin this field if it forwards the AS Group Context Reportmessage.Capability of Relay UE traversedThe capability of the Relay UE, e.g. whether support CPRelay or UP Replay for the reporting UE. Each Relay UEwill append its capability in this field when it forwards theAS Group Context Report message.

If a UE is one hop away from the AS Group Manager, e.g. UE2 and UE3 as shown inFIG.1, the UE can send a AS Group Context Report message directly to AS Group Management as shown in step1and3inFIG.11. After receiving the message, the AS Group Manager sends a AS Group Context Report Response message to the UE to confirm the message.

If a UE is multiple hops away from the AS Group Manager, e.g. UE 4 as shown inFIG.1. The UE 4 sends the AS Context Report towards the AS Group Manager via one or multiple neighbors. In one example, if UE 4 knows the UE that can forward AS Context Report message to the AS Group Manager, UE 4 will unicast the message to the UE, e.g. UE 3 inFIG.1.

In another example, if UE 4 does not know which UE can forward AS Context Report message to the AS Group Manager or does not receive a AS Group Context Report Response message from the AS Group Manager in the first example, UE 4 will broadcast the message to all its UE neighbors, e.g. UE 3, UE 5 and UE 8. When a UE, e.g. UE 3 inFIG.4, receives the message, it processes the message and decides whether to forward the message to the AS Group Manager as shown in step4inFIG.11The UE may decide whether to forward the message based on the following criteria:Forward if the Reporting UE is in the same ULG;Forward if it has Control Plane (CP) Relay or User Plane (UP) Relay function;Forward if the maximum number of forwarding is bigger than zero;Forward if the distance from the Reporting UE smaller than the maximum forward range;Forward if it has never received the message with same sequence number originated from the same Reporting UE.

If the UE decides to forward the message, it will decrease the value of maximum number of forwarding by one in the message and insert its AS ID configured by the network and capability information append in AS Group Context Report message, then sends the message towards AS Group Manager following the same procedure described above.

The AS Group Manager may receive multiple AS Group Context Report messages from the reporting UE via different paths. The AS Group Manager may choose a path to send the AS Group Context Report Response. The response may contain the AS ID of each relay UE on the path, and these relay UEs forward the response to the reporting UE. After receiving the response, the d Reporting UE knows the Neighbor UE that can forward AS Context Report message to the AS Group Manager for future AS Group Context Report message.

Active Discovery Procedure

In the active discovery procedure, a UE has been pre-configured or configured a AS ID assigned by the network. SL AS Group Manager retrieves AS group context information of all UEs within a service range. In the active discovery procedure, SL AS Group Manager sends an AS Group Context Request message to all UEs within a service range as shown inFIG.12The SL AS Group Manager may send AS Group Context Request message periodically, when it receives a Group Management Request from upper layer or a AS Group Management Request from another node in the network as shown in step0inFIG.12. The AS Group Management Request message may include but is not limited to the information shown in Table 3. The AS Group Context Request message may include but not limited to information shown in Table 4.

TABLE 3AS Group Management Request MessageFields nameDescriptionAS group IDsAS IDs associated with ULG that the node requests the ASGroup Manager to manage.PositionThe position of the node that sends the request, e.g. the GPSlocation.Service rangeThe range within which the node requests the AS GroupManager to manage the group.

TABLE 4AS Group Context Request MessageFields nameDescriptionAS ID of the AS Group ManagerThe AS ID of the AS Group Manager that sends the request.AS ID of the Reporting UEsThe AS ID of the UEs that report the AS group contextinformation via a response after receiving the request. If thisfield is empty, all UEs that receive the request with adifferent sequence number should send a response to reporttheir AS group context information.Sequence NumberThe sequence Number generated by the AS Group Managerto differentiate the AS Group Context Request message itsends. For example, the sequence number is increased byone for each new AS Group Context Request messagegenerated.PositionThe position of the AS Group Manager or the node that sendsthe group management request, e.g. the GPS locationMaximum number of forwardingThe maximum number of times the AS Group ContextRequest can be forwarded. This value is decreased by onewhen the AS Group Context Request is forwarded by a RelayUE. The AS Group Context Request message which containszero value of maximum forward time will be discarded.Maximum forward physical rangeThe maximum distance the AS Group Context Request canbe forwarded. A UE will not forward a AS Group ContextRequest message originated from the AS Group Manager, ifthe distance to the AS Group Manager is bigger than themaximum forward range.AS group IDsAS IDs associated with ULGs that the AS Group Managerrequest to discover. If this field is not empty, only the UEthat belongs to one of the ULGs reports the AS group contextinformation.AS IDs of Relay UEs traversedThe AS ID of each Relay UE the AS Group Context Requestmessage has traversed. Each Relay UE will append its AS IDin this field if it forwards the AS Group Context Requestmessage.

If the AS Group Manager knows a UE within a service range and the Relay UEs that can forward AS Context Request message to the UE within a service range. The AS Group Manager will unicast the message to the UE via relay UEs. For example, the AS Group Manager sends a AS Group Context Request to UE3, UE 3 will forward the request UE 4. When UE 4 receives the request, it reports its AS group context information to the AS Group Manager via the AS Group Context Response message. The AS Group Context Response message includes but not limited as shown in Table 4. The UE 3 also forwards the AS Group Context Response back to AS Group Manager.

TABLE 5AS Group Context Response MessageFields nameDescriptionAS ID of the AS Group ManagerThe AS layer ID of the AS Group Manager that sends therequest.AS ID of the Reporting UEThe AS ID of the UE that reports the AS group contextinformation via a response after receiving the request.Sequence NumberThe Sequence Number received in the request.AS group context informationAs described in Table 1.AS IDs of Relay UEs traversedThe AS ID of each Relay UE the AS Group Context Requestmessage has traversed. The Relay UE may use thisinformation to forward the response back to the AS GroupManager.

If the AS Group Manager does not know all UEs within a service range nor the Relay UEs that can forward AS Context Request message to each UE within a service range. AS Group Manager broadcasts the AS Group Context Request message to all UEs within a service range. The AS Group Manager first broadcasts a AS Group Context Request to its neighbors, e.g. UE 2, UE 3, UE 5, and UE 7 inFIG.1. When a UE, e.g. UE 3, receives the message, it processes the message and decides whether to forward the message to its neighbors as shown in step5inFIG.12. The UE may decide whether to forward the message based on the following criteria:Forward if the UE belongs to the same ULG as indicated in AS group IDs field in the request;Forward if it has Control Plane (CP) Relay or User Plane (UP) Relay function;Forward if the maximum number of forwarding is bigger than zero;Forward if the distance from the AS Group Manager is smaller than the maximum forward range;Forward if it has never received the message with same sequence number originated from the AS Group Manager.

If the UE decides to forward the message, it will decrease the value of maximum number of forwarding by one in the message and insert its AS ID configured by the network append in AS Group Context Request message, then broadcasts the message to its neighbors following the same procedure described above.

A UE may receive multiple AS Group Context Request messages from the AS Group Manager via different paths. The UE may choose a path to send the AS Group Context Report Response. The response may contain the AS ID of each relay UE on the path, and these relay UEs forward the response to AS Group Manager.

Centralized AS Sub-group formation and Configuration

Based on the obtained AS context information during AS group context discovery, SL AS Group Manager organizes the ULG into AS layer sub-groups, configures UE-to-UE relays for each UE, and send the AS subgroup configuration information to the UE via dedicated control messages. The procedure can be triggered if the AS Group Context is changed after a group context discovery procedure. The procedure can also be triggered if the AS Group Manager receives a request from upper layer or an AS group management request from another node in the network as shown in step0inFIG.13.

TABLE 6AS Group Management Information for a ULG MemberFields nameDescriptionAS ID of ULG memberThe AS ID of the UEs that are in the ULGPath to ULG memberThe path from AS Group Manager to the UEManagement Information of ASThe subgroup information for each subgroup associated withsubgroup Groupthe ULG as described in Table 7

TABLE 7AS Subgroup Management Information for a ULG MemberFields nameDescriptionAS ID of SubgroupThe AS ID of subgroup.Communication ModeThe communication mode to transmit a message to the group,e.g. multicast or unicast.AS ID of Subgroup member 1AS ID of the UEs that are in the subgroup.Path to Subgroup member 1The path from the UE to the subgroup member.AS ID of Subgroup member nAS ID of the UEs that are in the subgroup.Path to Subgroup member nThe path from the UE to the subgroup member.

For each ULG, the AS Group Manager organizes the ULG to AS subgroup for each UE in the ULG as shown at step1inFIG.13. The algorithm about how to divide a ULG into subgroups is out of scope of the disclosure. The AS group management information is stored at the AS Group Manager as shown in Table 6. Using the topology inFIG.1as an example, ULG 1 contains UE 2, 4, 6, 7 and 8. The AS Group Manager creates group management information for each UE in the ULG. For example, for UE 2, the AS Group Manager organizes the ULG 1 into three subgroups. Subgroup 1 contains UE 6 and 7 that can be reached via a multicast transmission. Subgroup 2 contains UE 8 that can be reached via a unicast transmission. Subgroup 3 contains UE 4 that can be reached via a unicast transmission to UE 5, which forwards the message to UE 4. The AS ID of subgroup can be generated based on the AS ID of the ULG 1 and the AS ID of UE 2, which is unique within the proximity. Based on the AS Group Management information, the AS Group Manager configures each UE in the ULG via subgroup configuration request. InFIG.13, steps2-7show an example that the AS Group Manager configures UE 2 and its Subgroup 3 which contains UE 4.

At step2, the AS Group Manager sends a subgroup configuration request to UE 2. The subgroup configuration request contains AS ID of the ULG and the information for each AS subgroup as described in Table 8. After receiving the message, UE 2 knows the ULG 1 contains UE 2, 4, 6, 7, and 8 and three AS subgroups. Subgroup 1 contains UE 6 and 7 that can be reached via a multicast transmission. Subgroup 2 contains UE 8 that can be reached via a unicast transmission. Subgroup 3 contains UE 4 that can be reached via a unicast transmission to UE 5, which forwards the message to UE 4.

At step3, UE 2 sends a subgroup configure response to confirm the subgroup configurations.

At step4, the AS Group Manager sends a subgroup configuration request to UE 5. The subgroup configuration request contains AS subgroup information of subgroup 3 as described in Table 8. After receiving the request, UE 5 knows if it receives a message originated from UE 2 for AS subgroup 3, it will forward message to UE 4.

At step5, UE 5 sends a subgroup configure response to confirm the subgroup configurations.

At step6, the AS Group Manager sends a subgroup configuration request to UE 4. Since the UE 4 is more than one hop away from the AS Group Manager, the message can be relayed by UE 3 or UE 5. The subgroup configuration request contains AS subgroup information of subgroup 3 as described in Table 8. After receiving the request, UE 4 knows it may receive a groupcast message originated from UE 2 for AS Subgroup 3.

At step7, UE 4 sends a subgroup configure response to confirm the subgroup configurations. Since UE 4 is more than one hop away from the AS Group Manager, the message can be relayed by UE 3 or UE 5.

TABLE 8AS Subgroup Configuration RequestFields nameDescriptionAS ID of Groupcast OriginatorAS ID of the UE that generates groupcast message.AS ID of ULGThe AS ID of the ULG.AS ID of SubgroupThe AS ID of subgroup.Relay FunctionWhether the UE is select as a relay UE.Communication ModeThe communication mode to relay the message.AS ID of Subgroup member 1AS ID of the UE that is 1stsubgroup member in the subgroup.AS ID of Relay UEs for SubgroupAS ID of the Relay UEs that forward the message to themember 1subgroup member 1.AS ID of Subgroup member nAS ID of the UE that is nthsubgroup member in thesubgroup.AS ID of Relays UE for SubgroupAS ID of the Relay UEs that forward the message to themember nsubgroup member N.
Distributed AS Group Management Procedures

In the distributed approach, each UE discovers group members and obtains their AS group context information. Based on the obtained AS group context information of group members, the UE organizes the ULG into AS layer subgroups and configures UE-to-UE relays via dedicated message.

Distributed AS Group Discovery Procedures

In the distributed AS group management approach, each UE discovers group members and obtains their AS context information. Two distributed AS group discovery procedures, e.g., proactive and reactive discovery procedures are disclosed. In the proactive discovery procedure, each UE periodically sends its AS group context information to all UE within a service range. In the reactive discovery procedure, a UE sends discovery requests to and receives discovery response from all UEs within the service range to obtain AS group context information. The AS group context information includes but not limited filed show in Table 1. Note that a UE periodically exchanges AS layer messages with neighbors to obtain AS context information of neighbors.

Proactive Discovery Procedure

In the proactive discovery procedure, a UE has been pre-configured or configured a AS ID assigned by the network. The method about how a UE is pre-configured or configured is out of the scope of the disclosure. In the proactive discovery procedure, a UE sends AS group context information to all UEs within a service range via AS Group Context Advertisement messages as shown inFIG.14. A UE may send AS Group Context Advertisement message periodically, or when its AS group context information changed as shown in step0. To illustrate the disclosed procedure, UE 4 inFIG.1is used as an example.

TABLE 9AS Group Context Advertisement MessageFields nameDescriptionAS ID of the Advertising UEThe AS ID of the UE that advertises the AS group contextinformation, which is configured by the network orscheduling entity.Sequence NumberThe sequence number generated by the reporting UE todifferentiate the AS Group Advertisement Report message itsends. For example, the sequence number is increased byone for each new AS Group Context Advertisement messagegenerated.PositionThe position of the UE, e.g. the GPS location.Maximum number of forwardingThe maximum number of times the AS Group ContextAdvertisement can be forwarded. This value is decreased byone when the AS Group Context Advertisement is forwardedby a Relay UE. The AS Group Context Advertisementmessage which contains zero value of maximum forwardtime will be discarded.Maximum forward physical rangeThe maximum distance the AS Group Context Advertisementcan be forwarded. A UE will not forward a AS GroupContext Advertisement message originated from a reportingUE, if the distance to the reporting UE is bigger than themaximum forward range.AS group context informationAs described in Table 1.AS IDs of Relay UEs traversedThe AS ID of each Relay UE the AS Group ContextAdvertisement message has traversed. Each Relay UE willappend its AS ID in this field if it forwards the AS GroupContext Advertisement message.Capability of Relay UE traversedThe capability of the Relay UE, e.g. whether support CPRelay or UP Replay for the reporting UE. Each Relay UEwill append its capability in this field when it forwards theAS Group Context Advertisement message.

At step1, the UE 4 sends the AS Context Advertisement message to all its neighbors, e.g. UE 3, UE 5 and UE 8. In the message, the UE may include but not limited to information shown in Table 9.

At step2a, when a UE, e.g. UE 5, receives the message, it processes the message and decides whether to forward the message to its neighbors. If UE 5 has never received the message with same sequence number originated from the same UE, UE 5 will store or update the AS group context information associated with UE 4. Otherwise, UE 5 will discard the message. UE 5 may decide whether to forward the message to its neighbors based on the following criteria:Forward if the Advertising UE is in the same ULG;Forward if it has Control Plane (CP) Relay or User Plane (UP) Relay function;Forward if the maximum number of forwarding is bigger than zero;Forward if the distance from the Advertising UE smaller than the maximum forward range;Forward if it has never received the message with same sequence number advertised from the same UE.

If the UE decides to forward the message, it decreases the value of maximum number of forwarding by one in the message and may insert its AS ID configured by the network and capability information appended in AS Group Context Advertisement message, then sends the message to all its neighbors except the transmitter of the message as shown in step3.

At step2b, UE 8 follows the same procedure as UE 5 in step2a.

At step3, UE 5 then sends the AS Group Context Advertisement message to all its neighbors except the transmitter of the message.

At step4, UE 8 follows the same procedure as UE 5 in step2a. Since UE 8 already receives a AS Group Context Advertisement message from UE 4 with the same sequence number, UE 8 will discard the message.

At step5, UE 8 then sends the AS Group Context Advertisement message to all its neighbors except the transmitters of the message.

Reactive Discovery Procedure

In the reactive discovery procedure, a UE has been pre-configured or configured a AS ID assigned by the network. Each UE retrieves AS group context information of all ULG member UEs within a service range. A UE sends a AS Group Context Discovery message to all UEs within a service range as shown inFIG.15. The UE may send the message periodically or when it receives a request to transmit a groupcast message from upper layer but does not know its ULG members as shown in step0inFIG.12. The AS Group Context Discovery message may include but not limited to information shown in Table 10. After receiving the AS Group Context Discovery message, A UE that in the same ULG sends a response back to the initiating UE and provides AS group context information.

TABLE 10AS Group Context Discovery MessageFields nameDescriptionAS ID of the Initiating UEThe AS layer identification of the UE that initiates the ASGroup Context Discovery message.AS ID of the Group Member UEsThe AS ID of the Group Member UEs that report the ASgroup context information via a response after receiving therequest.Sequence NumberThe sequence Number generated by the Initiating UE todifferentiate the AS Group Context Discovery message itsends. For example, the sequence number is increased byone for each new AS Group Context Discovery messagegenerated.PositionThe position of the Initiating UE, e.g. the GPS location.Maximum number of forwardingThe maximum number of times the AS Group ContextDiscovery message can be forwarded. This value isdecreased by one when the AS Group Context Discoverymessage is forwarded by a Relay UE. The AS GroupContext Discovery message which contains zero value ofmaximum forward time will be discarded.Maximum forward physical rangeThe maximum distance the AS Group Context Discoverymessage can be forwarded. A UE will not forward a ASGroup Context Request message originated from theInitiating UE, if the distance to the Initiating UE is biggerthan the maximum forward range.AS group IDsAS IDs associated with ULG that the Initiating UE request todiscover. If this field is not empty, only the UE that belongsto one of the ULGs reports the AS group context information.AS IDs of Relay UEs traversedThe AS ID of each Relay UE the AS Group ContextDiscovery message has traversed. Each Relay UE willappend its AS ID in this field if it forwards the AS GroupContext Discovery message.

TABLE 11AS Group Context Discovery Response MessageFields nameDescriptionAS ID of the Initiating UEThe AS layer identification of the UE that initiates the ASGroup Context Discovery message.AS ID of the Reporting UEThe AS ID of the UEs that report the AS group contextinformation via a response after receiving the AS GroupContext Discovery message.Sequence NumberThe Sequence Number received in the AS Group ContextDiscovery message.AS group context informationAs described in Table 1.AS IDs of Relay UEs traversedThe AS ID of each Relay UE the AS Group ContextDiscovery message has traversed. The Relay UE may usethis information forward the response back to the InitiatingUE.

To illustrate the disclosed procedure, UE 2 inFIG.1is used as an example.

At step1, the Initiating UE sends the AS Group Context Discovery message to its one hop neighbors. The AS Group Context Discovery message may include but not limited to information shown in Table 10. For example, the UE 2 broadcasts a AS Group Context Request to its neighbors, e.g. UE 1 and 5-8 inFIG.1. The UE 2 may contain the list of AS ID of group member in ULG 1, e.g. UE 2, 4, 6, 7 and 8 in the message. These UEs will send a response to UE 2 after receiving the message. The UE 2 may contain the AS ID of ULG 1.

At step2a, when a UE, e.g. UE 8, receives the message, it processes the message and decides whether to forward the message to its neighbors. If UE 8 has never received the message with same sequence number originated from the same UE and UE 8 is in ULG 1, UE 8 will send a AS Group Context Discovery Response back to UE 2. UE 8 may decide whether to forward the message to its neighbors based on the following criteria:Forward if the Initiator UE is in the same ULG;Forward if it has Control Plane (CP) Relay or User Plane (UP) Relay function;Forward if the maximum number of forwarding is bigger than zero;Forward if the distance from the Initiator UE smaller than the maximum forward range;Forward if it has never received the message with same sequence number originated from the same UE.

If the UE decides to forward the message, it decreases the value of maximum number of forwarding by one in the message and may insert its AS ID configured by the network and the capability information appended in AS Group Context Discovery message, then sends the message to all its neighbors except the transmitter of the message as shown in step4.

At step2b, UE 5 follows the same procedure as UE 8 in step2a.

At step3, UE 8 sends a AS Group Context Discovery Response back to UE 2. The AS Group Context Discovery Response message may include but not limited to information shown in Table 11.

At step4, UE 8 then sends the AS Group Context Discovery message to all its neighbors except the transmitter of the message, e.g. UE 4 and UE 5.

At step5, UE 5 follows the same procedure as UE 8 in step2a. Since UE 5 already receives a AS Group Context Discovery from UE 2 with the same sequence number, UE 5 will discard the message.

At step6, UE 5 then sends the AS Group Context Discovery message to all its neighbors except the transmitters of the message, e.g. UE 4.

At step7, a UE may receive multiple AS Group Context Report messages from the Initiator UE via different paths. The UE may choose a path to send the AS Group Context Discovery Response. The AS Group Context Discovery Response message may include but not limited to information shown in Table 11. The response may contain the AS ID of each relay UE on the path, and these relay UEs forward the response to Initiator UE. For example, UE 4 sends a AS Group Context Discovery Response back to UE 2 via UE 5.

At step8, UE 5 forward the AS Group Context Discovery Response to UE 2.

AS sub-Group Configuration Procedure.

Based on the obtained AS context information during AS group context discovery, the Initiator UE organizes the ULG into AS layer sub-groups, configures UE-to-UE relays for each UE and send the AS subgroup configuration information to the UE via dedicated control messages. The procedure can be triggered if the AS group context is changed after a group context discovery procedure. The procedure is the same as the centralized procedure described in section 5.2.1.2 except the Initiator UE organizes the ULG into AS layer subgroups and sends subgroup configuration request to configure UE-to-UE relays for each group member and sends the AS subgroup configuration to each group member as shown inFIG.16.

Bearer Management to Support Groupcast

Detail Layer 2 procedures are disclosed to support each disclosed Layer 2 (L2) structures. The L2 structure view for Sidelink groupcast is shown inFIG.17. A Layer 2 source and destination ID will be included in each MAC PDU. Packets with different Source Layer-2 ID-Destination Layer-2 ID pair cannot be multiplexed into the same MAC PDU. For the groupcast, the destination ID is the AS ID of the subgroup which is generated based on AS ID of the group and the AS ID of the originator. Therefore, the AS ID of the subgroup will be unique within a local network. The source ID is the AS ID of the UE configured by the network. The MAC layer of each UE has a packet filter function, which delivers a packet to the upper layer if the destination ID of the packet matches the AS ID of subgroups. A UE is configured with a AS ID of a subgroup if it is a member of the subgroup or it serves as a UP Relay to forward groupcast message to a UE which is a member of the subgroup.

To illustrate the disclosed procedures, topology inFIG.1is used as an example. InFIG.1, UE 2, 4, 6, 7, and 8 are in the same ULG (ULG), e.g., ULG 1. UE 2 receives a groupcast message from upper layer and intends to transmit it to all UEs in ULG 1. UE 2 maps the ULG 1 to three AS subgroups. Subgroup 1 contains UE 6 and 7 that can be reached via a multicast transmission. Subgroup 2 contains UE 8 that can be reached via a unicast transmission. Subgroup 3 contains UE 4 that can be reached via a unicast transmission to UE 5, which forwards the message to UE 4. UE 5 is a UP Relay that forwards groupcast messages from UE 2 to UE 4. A UP Relay can be a Layer 2 Relay as shown inFIG.18,FIG.19, andFIG.20. To do the Layer 2 Relay at RLC as shown inFIG.18, the AS ID of the groupcast transmitter and AS ID of the subgroup should be contained in the RLC header. To do the Layer 2 Relay at PDCP as shown inFIG.19, the AS ID of the groupcast transmitter and AS ID of the subgroup should be contained in the PDCP header. To do the Layer 2 Relay at PDCP as shown inFIG.19, the AS ID of the groupcast transmitter and AS ID of the subgroup should be contained in the SDAP header.

Subgroup Mapping at SDAP Entity

In this example, when the AS Layer receives a groupcast request from upper layer, the SDAP is configured with group management information as described in Table 6. Based on the information, SDAP entity divides the group into subgroups. Each subgroup has its unique AS subgroup ID as the destination ID. Packets associated with different subgroups have separated radio bearers, which may use a different communication mode. For example, the SDAP at UE 2 makes three duplications of the packet. Each packet has a different destination ID which is the AS ID of the subgroup. Each radio bearer associated with a subgroup receives a copy of the packet. The communication mode of the radio bear associated with subgroup 1 is multicast/broadcast. The communication mode of the radio bear associate with subgroup 2 and 3 is unicast mode. When the MAC layer at UE 5 receives the message with MAC destination ID is the AS ID of subgroup 3 from UE 2, it delivers the packet to the upper sublayer. Since UE 5 is configured as a Relay UE for the subgroup, the RLC, PDCP, or SDAP sublayer relays the packet to UE 4. The source layer 2 ID in the MAC PDU is the AS ID of UE 5 and the destination ID in the MAC PDU is the AS ID of subgroup 3.

Subgroup Mapping at PDCP Entity

In this example, when the AS Layer receive a groupcast request from upper layer, the PDCP entity is configured with group management information as described in Table 6. Based on the information, PDCP entity divides the group into subgroups. Each subgroup has its unique AS subgroup ID as the destination ID. Packets associated with different subgroups have separated RLC Channels, which may use a different communication mode. For example, the PDCP at UE 2 makes three duplications of the packet. Each packet has a different destination ID which is the AS ID of the subgroup. Each RLC Channel associated with a subgroup receives a copy of the packet. The communication mode of the RLC Channel associated with subgroup 1 is multicast/broadcast. The communication mode of the radio bear associate with subgroup 2 and 3 are unicast mode. When the MAC layer at UE 5 receives the message with MAC destination ID is the AS ID of subgroup 3 from UE 2, it delivers the packet to the upper sublayer. Since UE 5 is configured as a Relay UE for the subgroup, the RLC, PDCP or SDAP sublayer relays the packet to UE 4. The source layer 2 ID in the MAC PDU is the AS ID of UE 5 and the destination ID in the MAC PDU is the AS ID of subgroup 3.

Subgroup Mapping at RLC Entity

In this example, when the AS Layer receives a groupcast request from upper layer, the RLC entity is configured with group management information as described in Table 6. Based on the information, the RLC entity divides the group into subgroups. Each subgroup has its unique AS subgroup ID as the destination ID. Packets associated with different subgroups have separated Logical Channels, which may use a different communication mode. For example, the RLC at UE 2 makes three duplications of the packet. Each packet has a different destination ID which is the AS ID of the subgroup. Each Logical Channel associated with a subgroup receives a copy of the packet. The communication mode of the Logical Channel associated with subgroup 1 is multicast/broadcast. The communication mode of the radio bear associate with subgroup 2 and 3 are unicast mode. When the MAC layer at UE 5 receives the message with MAC destination ID is the AS ID of subgroup 3 from UE 2, it delivers the packet to the upper sublayer. Since UE 5 is configured as a Relay UE for the subgroup, the RLC, PDCP or SDAP sublayer relays the packet to UE 4. The source layer 2 ID in the MAC PDU is the AS ID of UE 5 and the destination ID in the MAC PDU is the AS ID of subgroup 3.

The RLC entity makes the duplications of RLC PDU based on the number of subgroups and sends the PDU with different transmission mode to different Logical Channels. For example, if the initial transmission using multicast fails, the RLC entity can retransmits the packet using unicast mode to each group member that does not receive the message.

Abbreviations

The following is a list of acronyms that may appear in the above description. Unless otherwise specified, the acronyms used herein refer to the corresponding term listed below:

3GLTEThird Generation Long Term Evolution3GPP3rdGeneration Partnership Project5GFifth Generation Wireless TechnologyACKACKnowledgementAFApplication FunctionAMFAccess and Mobility Management FunctionAPAccess PointAPPApplicationARAugmented RealityASAccess StratumAS IDThe ID in the AS layer. The AS ID can be configured by thenetwork or scheduling entity. An example of an AS ID is LinkLayer (Layer 2) ID, which can be use as Layer 2 Source IDand Layer 2 destination ID.ASICsApplication Specific Integrated CircuitsAUSFAuthentication Server FunctionBSCBase Station ControllerBTSBase Transceiver StationBTSBase Transceiver StationCD-ROMCompact Disk-Read Only MemoryCPControl PlaneCUEspecial cooperative UED2DDevice to Device CommunicationDLDownlinkDSPDigital Signal ProcessorDVDDigital Video DiscEDGEEnhanced Data rates for GSM EvolutioneMBBEnhanced Mobile BroadbandeNBEvolved Node BeNodeBevolved home node-BE-UTRAEvolved UMTS Terrestrial Radio AccesseV2XEnhanced Vehicle-to-EverythingFMFrequency ModulatedFPGAsField Programmable Gate ArrayGGSNGateway GPRS Support NodegNBNR NodeBgNode-Ba next generation node-BGPRSGeneral Packet Radio ServiceGPSGlobal Positioning SystemGSMGlobal System for Mobile communicationsGUIGraphical User InterfaceHARQHybrid Automatic Repeat RequestHeNBa home evolved node BHSDPAHigh-Speed Downlink Packet AccessHSPAHigh-Speed Packet AccessHSUPAHigh-Speed Uplink Packet AccessICIntegrated CircuitIDIdentity or IdentifierIMSIP Multimedia SubsystemIPInternet ProtocolIRMicrowave InfraredIS-856Interim Standard 856IS-95Interim Standard 95ITSIntelligent Transport SystemITS-AIDITS Application IdentifierIuCSan interface toward the CS (circuit switching) domain of thecore networkIuPSan interface toward the PS (packet switching) domain of thecore networkL2Layer 2LCDliquid crystal displayLCHLogical ChannelLTELong Term EvolutionLTE-ALong Term Evolution AdvancedMACMedium Access ControlMGWMedia GatewayMIMOMultiple-Input Multiple OutputMMEMobility Management GatewayGatewaymMTCMassive Machine Type CommunicationsMSCMobile Switching CenterN3IWFNon-3GPP Interworking FunctionNASNon-Access StratumNBNodeBNEFNetwork Exposure FunctionNRNew RadioOLEDOrganic light-emitting diodePC3A reference point between ProSe-enabled UEs and a ProSenetwork function.PC5A reference point between ProSe-enabled UEs used forcontrol and user plane for ProSe Direct Discovery, ProSeDirect Communication and ProSe UE-to-Network RelayPCFPolicy Control FunctionPDApersonal digital assistantPDCPPacket Data Convergence ProtocolPDNPacket Data NetworkPDUProtocol Data UnitPHYPhysical layerPOTSPlain Old Telephone ServiceProSeProximity-Based ServicesPSIDProvider Service IdentifierPSTNPublic Switched Telephone NetworkQoSQuality of ServiceRAMrandom-access memoryRANRadio Access NetworkRATradio access technologyRFRadio FrequencyRGResidential GatewayRLCRadio Link ControlRNCRadio Network ControllerROMread-only memoryRRCRadio Resource ControlRRHsRemote Radio HeadsRSURoadside UnitRxGroupcast ReceiverSDSecure DigitalSDAPService Data Adaptation ProtocolSDUService Data UnitSGSNServing GPRS Support NodeSIMsubscriber identity moduleSLSidelinkSMFSession Management FunctionSMSshort message serviceTCPTransmission Control ProtocolTRPsTransmission and Reception PointsTxGroupcast TransmitterUDMUser Data Management FunctionUDPUser Datagram ProtocolUDRUser Data RepositoryUEUser EquipmentULUplinkULGUpper Layer GroupUMTSUniversal Mobile Telecommunications SystemUPUser PlaneUPFsUser Plane FunctionsURLLCUltra-Reliable Low-Latency CommunicationUSBUniversal Serial BusUTRATerrestrial Radio AccessUVUltra VioletV2IVehicle-to-InfrastructureV2NVehicle-to-NetworkV2PVehicle-to-PersonV2VVehicle-to-VehicleV2XVehicle-to-X CommunicationVRVirtual RealityWCDMAWideband CDMAWiMAXWorldwide Interoperability for Microwave AccessWTRUWireless Transmit/Receive Unit