Communication method between network elements connected to a public land mobile network

Abstract

The present disclosure relates to a communication method between a first network element connected to a first public land mobile network and a second network element connected to a second public land mobile network, where the second network element is not connected to the first public land mobile network, and the method comprises initiating the provisioning of authorization for the second network element to access specific network resources of the first public land mobile network, the authorization enabling the second network element to access the specific network resources only for a specific use related to communication with the first network element, provisioning authorization for the second network element in the first public land mobile network, and accessing specific network resources of the first public land mobile network for a specific use in the second network element, and relates to a method comprising at least one of these elements.

Description

Technical Field

[0001] This disclosure belongs to the field of telecommunications.

[0002] In particular, a communication method, a computer program, an application server, a federation manager, an authorization provisioning module, and a network element are disclosed.

Background Art

[0003] In various technical fields, optimizing device - to - device communication between user equipment (UE) connected to different public land mobile networks (PLMN) or other network elements is an issue that occurs repeatedly.

[0004] High - quality vehicle - to - everything (V2X) applications are an example of applications that need to frequently configure and re - configure communication between a UE related to a vehicle and connected to a PLMN and various network elements connected to the same PLMN or other PLMNs.

[0005] Some methods of providing V2X services between two UEs connected to different PLMNs are known.

[0006] As one possibility, vehicle - to - network - to - vehicle (V2N2V) communication via the network can be used to establish V2X communication via each PLMN. To do this, each UE connects to a base station (gNB) within its own PLMN and performs, for example, LTE - Uu or 5G Uu - based V2X communication, and the two PLMNs may exchange control - layer and / or application - layer data regarding each UE.

[0007] General steps for setting up this V2N2V communication are given as the detection of high - level application support of the UEs participating in the communication and the establishment of a low - level PC5 link between the UEs connected to each PLMN.

[0008] The detection step between PLMNs may be based on two detection protocols described in TS 23.303 / TS 23.304, and an overview of this is described below. In this overview, it is assumed that the first user equipment UE-A is camped on the first public land mobile network PLMN-A, and the second user equipment UE-B is camped on the second public land mobile network PLMN-B.

[0009] Both UE-A and UE-B obtain application parameters, such as application identifiers and / or group identifiers, from the V2X application layer. UE-A determines its own source L2 transmission identifier corresponding to the PC5 identifier of UE(A) at the media access control (MAC) level. UE-B also determines its own source L2 transmission identifier.

[0010] UE-A notifies its neighboring UEs of its L2 transmission identifier. In the prior art, basically a single PLMN deployment is considered.

[0011] UE-B receives packets tagged with the L2 source transmission identifier from UE-A and responds to UE-A.

[0012] When UE-A receives a response tagged with the L2 source transmission identifier of UE-A from UE-B, it sets UE-B as the detected UE.

[0013] Finally, UE-A and UE-B each request the establishment of a sidelink at the physical layer (PC5 link) by communicating via the radio access network (NG-RAN) of each respective PLMN. The processing of the request involves the NG-RAN and the core networks of PLMN-A and PLMN-B.

[0014] The establishment of the sidelink at the physical layer consists of obtaining authorization, security certificates, QoS policy parameters, and various other parameters.

[0015] The overall procedure, i.e., the detection and establishment of the PC5 link as described above, has the drawback that a very long waiting time occurs.

[0016] As another possibility, there is a roaming-based solution. In this solution, a single PLMN deploys a network in a specific geographical area to provide V2X services. However, the roaming-based solution has the inconveniences of lack of flexibility and deployment limitations. It is necessary to co-deploy adjacent PLMNs. Roaming between operators at the boundary of the covered area results in long waiting times and leads to service interruptions.

[0017] In 3GPP (trademark) specifications TS23.287 and TS23.304, architecture support is introduced to enable UE-A connected to PLMN-A to detect UE-B connected to PLMN-B and, in some cases, initiate basic direct communication via the PC5 (side link) interface with UE-B. The described features include providing the UE with a pre-configuration including a permitted PLMN list for monitoring detection resources. There is an interconnection at the core network level between two PLMNs. Nevertheless, there is no further support for this feature at the lower layer. Furthermore, a rather long waiting time occurs for the configuration or reconfiguration of PC5 parameters between PLMNs.

[0018] Therefore, there is a need for a framework that can establish and maintain direct communication between user equipment connected to different PLMNs with improved latency. Summary of the Invention Problems to be Solved by the Invention

[0019] The present invention is defined by the appended independent claims. Further features and advantages of the concepts disclosed herein are set forth in the following description.

[0020] The object of the present invention is to overcome the above limitations.

Means for Solving the Problem

[0021] Therefore, here, a communication method between a first network element connected to a first public land mobile network PLMN-A and a second network element connected to a second public land mobile network PLMN-B, wherein the second network element is not connected to the first public land mobile network PLMN-A, The method is related to authorization for the second network element to access specific network resources of the first public land mobile network PLMN-A, and the authorization enables only the second network element to access specific network resources for a specific purpose related to communication with the first network element, and the method starting the provisioning of authorization, in the first public land mobile network, provisioning authorization to the second network element, and in the second network element, accessing specific network resources of the first public land mobile network for a specific purpose, A method is disclosed that includes at least one of the above elements.

[0022] By the proposed method, any network element can use a feedback channel within a resource pool managed by the same PLMN when receiving an initial communication from a UE within a given PLMN. Advantages of the proposed method include that a specific framework is provided, for example, for the multi-PLMN establishment of a PC5 link, and such a specific framework enables such a link to be established in a much shorter time than by known procedures.

[0023] Therefore, in unicast / multicast communication, the proposed method enables HARQ feedback. This is either a clear ACK / NACK response for the transmitted transport block or a NACK-only response (in the case of multicast). The ACK and / or NACK responses are transmitted via a channel whose physical resource allocation is directly linked to the physical layer parameters, e.g., the resource pool configuration, the resources occupied by the data transmission to which the ACK / NACK feedback relates, and, in the case of groupcast communication, the identification information of the receivers within the groupcast group.

[0024] Details regarding various options are provided below.

[0025] In one example, authorization provisioning is initiated based on application-level information obtained at an application server (AS) that processes application layer clients (APPs) running on a first network element and a second network element.

[0026] In one example, authorization provisioning is initiated based on application-level information obtained at a federation manager coupled to a first public land mobile network and a second public land mobile network, the federation manager having detected a service that includes an application server (AS) that processes application layer clients (APPs) running on a first network element and a second network element.

[0027] In one example, the application-level information includes an indication that both the first network element and the second network element are members of the same group of network elements.

[0028] In one example, the method further includes forming and / or managing a group of network elements connected to different public land mobile networks.

[0029] In one example, forming and / or managing a group of network elements is based on the collected data associated with the network elements. In one example, the collected data, for a given network element, · indicates a physical location, · estimates communication performance, · estimates service quality sustainability, and · includes grouping information with at least one other network element connected to the same public land mobile network, and includes at least one type of data among them.

[0030] In one example, the method includes transmitting assistance information to a first public land mobile network and a second public land mobile network, where the assistance information is related to an authorization to be provisioned.

[0031] In one example, the method includes performing a network adjustment between the first public land mobile network and the second public land mobile network based on the assistance information.

[0032] In one example, the assistance information includes an indicator or request for support between public land mobile networks.

[0033] In one example, the network adjustment is a core network adjustment and / or a radio access network adjustment.

[0034] In one example, the method further includes performing detection of a second network element, for example in a first public land mobile network, via communication with a second public land mobile network.

[0035] In one example, the method further includes performing detection of a second network element in a first public land mobile network by performing an exchange of information via at least a PC5 interface between the first network element and the second network element.

[0036] In one example, performing an exchange of information includes detecting a second network element via a PC5 interface in a first network element.

[0037] In one example, a particular network resource is associated with at least one physical resource that defines a physical channel of a first public land mobile network.

[0038] In one example, the physical channel is one of the following channels: namely, PSFCH, PSSCH, PUSCH, and PUCCH.

[0039] In one example, a particular use is to transmit hybrid automatic repeat request feedback to a first network element using network resources of a first public land mobile network in response to a data packet previously transmitted by the first network element when the second network element is an intended recipient of the data packet. The network resources are understood herein, for example, as one or more time slots, one or more time-frequency resources, and one or more physical resource blocks.

[0040] Furthermore, a computer program including instructions, which, when the program is executed by a processor, cause the processor to perform the foregoing method, is disclosed.

[0041] Furthermore, a processing circuit including a processor operably connected to a memory, where the processor is configured to perform the foregoing method, is disclosed.

[0042] Furthermore, an application server in a communication system comprising a first network element connected to a first public land mobile network PLMN-A and a second network element connected to a second public land mobile network PLMN-B, wherein the second network element is not connected to the first public land mobile network PLMN-A, and the first network element and the second network element each execute an application layer client (APP), · The application server (AS) processes the application layer client, · The application server is configured to send application-level information to an authorization provisioning start module, and the authorization provisioning start module is configured to start provisioning of authorization for the second network element to access specific network resources of the first public land mobile network PLMN-A based on the application-level information, and the authorization enables the second network element to access only the specific network resources for a specific use related to communication with the first network element. An application server is disclosed.

[0043] Furthermore, a federation manager in a communication system comprising a first network element connected to a first public land mobile network PLMN-A and a second network element connected to a second public land mobile network PLMN-B, wherein the second network element is not connected to the first public land mobile network PLMN-A, and the first network element and the second network element each execute an application layer client (APP), The federation manager is connected to the first public land mobile network and the second public land mobile network, The federation manager has detected a service including an application server (AS) that processes an application layer client (APP), The federation manager is configured to send application-level information to an authorization provisioning start module, and the authorization provisioning start module is configured to start the provisioning of authorization for a second network element to access specific network resources of a first public land mobile network PLMN-A based on the application-level information, and the authorization enables the second network element to access the specific network resources only for a specific use related to communication with the first network element. A federation manager is disclosed.

[0044] Furthermore, an authorization provisioning module in a communication system comprising a first network element connected to a first public land mobile network PLMN-A and a second network element connected to a second public land mobile network PLMN-B, wherein the second network element is not connected to the first public land mobile network PLMN-A. An authorization provisioning module is disclosed, which is configured to provision, in the first public land mobile network, authorization for a second network element to access specific network resources of a first public land mobile network PLMN-A, and the authorization enables the second network element to access the specific network resources only for a specific use related to communication with the first network element.

[0045] Furthermore, a network element in a communication system, the communication system further includes a corresponding network element connected to a first public land mobile network PLMN-A, the network element is connected to a second public land mobile network PLMN-B, the network element is not connected to the first public land mobile network PLMN-A, A network element is disclosed that is configured to access specific network resources of a first public land mobile network PLMN-A for a specific use related to communication with a corresponding network element.

[0046] The network element may be, without distinction, a user equipment or a base station of a second public land mobile network.

Brief Description of the Drawings

[0047]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0048] The present disclosure relates to a method for authorizing direct communication between public land mobile networks (PLMNs), provisioning parameters for such direct communication, and executing such direct communication, and corresponding devices.

[0049] More specifically, the proposed technology enables direct communication between a user equipment (UE-B) connected to a home network (PLMN-B) and at least one network element (A) that is a UE or another entity (e.g., gNB) of a different network (PLMN-A) via resources belonging to PLMN-A. UE-B is not connected to PLMN-A.

[0050] Note that, unlike the prior art, the proposed method does not include roaming, dual connectivity, and inter-PLMN detection. Thus, UE-B is configured to use the licensed spectrum of PLMN-B for its data transmission instead of the licensed spectrum of PLMN-A.

[0051] UE-B is only given special authorization to use a portion of the licensed spectrum of PLMN-A for limited and tightly controlled uses, such as sending HARQ messages in response to data packets transmitted by UE-A in the licensed spectrum of PLMN-A when network element A is included among the intended recipients of the packets.

[0052] Such special authorization may be obtained through services provided by the PLMN for the configuration of each UE based on subscription. The PLMN can guarantee a high controlled QoS, for example, by securing a large resource pool within the licensed spectrum for high-throughput applications, or by operating services under network management, for example, under "mode 1" resource allocation without collision using resource scheduling. As a result of a mutual or reciprocal agreement between PLMNs, special authorization may be obtained through such services, and such special authorization enables low-latency direct communication between network elements connected to different PLMNs and subscribed to the services.

[0053] Furthermore, the gNB of PLMN-A may be configured to directly send a reconfiguration message to a group of subscriber UEs (including, for example, UE-B) connected to other PLMNs. Such a reconfiguration message includes information related to a dedicated resource pool of PLMN-A that enables already established direct communication with network element A. When reconfiguring a direct communication link via gNB-level or RAN-level signaling messages or exchanges, there is no need to route any reconfiguration messages via the core network or via a specific multi-access edge computing layer common to multiple PLMNs. As a result, the reconfiguration latency is reduced.

[0054] In an exemplary embodiment, several possible aspects of the proposed method are briefly described here.

[0055] For example, considering a V2X communication system, the V2X application may first determine a group of network elements that can benefit from direct communication. This determination is based on application-level information and services that are considered immediately available in the V2X application.

[0056] Next, considering, for example, the group of network elements determined above, the V2X application may send application support information to the PLMN. Such application support information includes at least an indicator / request for inter-PLMN support for group members. The application support information may further include information regarding the application identification information of group members, information regarding one or more actions to be performed by the PLMN, and / or additional information, such as a validity timer.

[0057] After receiving the application support information, the PLMN may negotiate and exchange the information necessary for direct communication between group members at various network levels. The information to be exchanged is related to, for example, physical resource structure, configuration or reconfiguration, authorization restrictions, validity timers, authorization cancellation, presence of group members, identification information of group members, etc.

[0058] Based on the aforementioned negotiation and information exchange, the PLMN may set or cancel authorizations and provision parameters at various network levels for various purposes including the following. · To assist in V2X service detection, · To authorize group members to establish direct communication, · To authorize group members to have limited use of resources outside their connected PLMN, · To provision specific service quality and access configuration parameters for specific application group members to establish and maintain an actual direct link between group members, · To provision specific RAN-level parameters and their continuous updates for specific application group members.

[0059] The PLMN may further perform service support actions at various network levels to contribute to the maintenance of V2X service operation. Examples of service support actions that can be performed in the PLMN include the following. · In some cases, using RAN support to collect information about one or more group members, · To collect and ensure the exchange of information regarding service quality information about one or more group members, · To exchange radio resource information about one or more group members between the base stations to which the group members are connected, ·Trigger the issuance of specific paging messages if any of the group members are not in use.

[0060] Furthermore, the PLMN may be configured to provide information related to the service support status to the application layer.

[0061] Next, refer to Figure 1. Figure 1 shows an exemplary communication system 100. The communication system 100 includes two UEs, UE-A 116 and UE-B 118, both of which are connected to PLMNs, PLMN-A 104 and PLMN-B 110, respectively.

[0062] Each PLMN has a similar structure and includes a core network (CN, e.g., 5GC) 106, 112 and a radio access network (RAN, e.g., 5G-RAN) 108, 114 for processing the respective UEs.

[0063] In the application layer, a V2X application server (V2X-AS) 102 processes V2X application clients (V2X-APP) 120, 122. These are stored, installed, and launched on the respective UEs.

[0064] Figure 1 shows various types of communication links. ·The V2X-AS may communicate directly with the V2X-APP using the PC1 interface. ·The V2X-AS may further communicate with the PLMN. ·The UEs are processed by their connected PLMNs via their respective Uu links. ·The PC5 interface may be established between UE-A and UE-B.

[0065] The following specific aspects of the proposed technology, namely, ·Support for group formation and group management, ·Specific configuration and reconfiguration of physical resources, · Specific authorization provisioning and cancellation, which will be described here in connection with the exemplary communication system of FIG. 1.

[0066] Each of these aspects may include applying one or more of the following procedures. · Procedures by which the application layer assists PLMN-A and PLMN-B in supporting inter-PLMN services, · Procedures for signaling or cooperation between PLMN-A and PLMN-B at the core network level (e.g., policy and / or QoS adjustment), · Configuration or reconfiguration procedures at the RAN level, · Procedures for exchanging information via an existing PC5 side link between UE-A and UE-B.

[0067] Furthermore, based on the following description, it is assumed to be straightforward to implement the same aspects in a communication system including three or more PLMNs in order to authorize a group of UEs formed by UEs belonging to different PLMNs (B, C, D,...) in the PLMN list to have restricted access to the licensed resources of PLMN-A. Furthermore, based on the following description, it is assumed to be straightforward to mutually grant similar access to UE-A in the licensed resources of other PLMNs (B, C, D,...).

[0068] {Support for group formation and group management} Support for group formation and group management is an aspect of the proposed technology and will be described here.

[0069] V2X-AS may collect information regarding V2X-APP from multiple PLMNs and optionally combine them as needed to determine and / or predict the location and / or performance of UEs. Examples of the information taken for this purpose and the relevant sources of such information will be briefly introduced below.

[0070] For example, as described in nplcit7, the core network of the serving PLMN may include a Network Exposure Function (NEF) arranged to expose information regarding the location and capabilities of the UE. Also, as described in nplcit5, information regarding the location of the UE may be obtained individually from the ETSI MEC location API. Also, as described in nplcit6, information regarding the capabilities of the UE may be obtained individually from the Radio Network Information API. Also, as described in nplcit8, information regarding the location of the UE and the initial UE grouping in a different PLMN may be obtained individually from the vertical service enabling layer. Also, as described in nplcit9, the core network of the serving PLMN may include a Network Data Analytics Function (NWDAF) arranged to optionally provide information regarding the location and QoS sustainability of the UE individually in the form of a prediction. Further, the V2X-APP itself on the UE may individually provide an estimation of the location and capabilities of the UE.

[0071] Based on the determined and / or predicted location and / or capabilities of the UE, a group of UEs that can benefit from direct communication may be determined. In other words, the V2X application layer may determine a group of UEs (or V2X application layer group) for which the service performance can be improved by enabling the setup of direct communication. In the example of FIG. 1, UE-A and UE-B may be placed within the same UE group.

[0072] Once one or more UE groups are determined, the V2X application layer (V2X-AS) may generate a message containing information for assisting in the establishment of direct communication between UEs of the same UE group across PLMNs. The message from the V2X application layer may be sent to the core network CN of the involved PLMN and is the generated message.

[0073] In an embodiment, a message from the V2X application layer may functionally be an application support trigger for direct communication between involved PLMNs. In the example of FIG. 1, the involved PLMNs are PLMN-A and PLMN-B. The message may include, for example, requests to both PLMNs to provide inter-PLMN support for V2X application services. The message may further include an indication of one or more areas related to inter-PLMN support. The message may further include information for identifying a V2X application layer group of a group of one or more UEs and / or information for identifying an application of a group of one or more UEs. The message may further include additional parameters for indicating an expectation from the V2X application service from a quality of service (QoS) perspective. In the example of FIG. 1, the message from the V2X application layer may include information for assisting in establishing direct communication between PLMNs between UE-A and UE-B, and such information may include, for example, an indication of the area where both UE-A and UE-B are located and / or information for identifying an application of UE-A and UE-B and / or information for identifying a V2X application layer group of a group of UEs including both UE-A and UE-B and / or additional parameters for indicating an expectation from the V2X application service from a QoS perspective for communication between UE-A and UE-B.

[0074] In an embodiment, a message from the V2X application layer may functionally be one that instructs UEs in a V2X application layer group that the application requires inter-PLMN support. The UE may further be configured to report information regarding the V2X application layer group to the connected gNB upon receiving such an instruction. The information regarding the V2X application layer group is the result of a detection process triggered by the UE, and may include information regarding the number of detected UEs and the identification of the detected UEs. The detection process may be triggered when the UE receives an instruction that the application requires inter-PLMN support and / or at any time beforehand. For example, the UE may be configured to trigger such a detection process periodically so that the result is immediately available when the UE receives an instruction that the application requires inter-PLMN support. Optionally, the detection context may be maintained within different V2X application functions of the involved PLMNs, and the results of the detection process triggered by the UE may be exchanged between the V2X application functions of the involved PLMNs.

[0075] When a message from the V2X application layer is an application assistance trigger for direct communication between the involved PLMNs, the core network of the involved PLMNs may be configured to adjust when receiving such a message. The adjustment between the involved PLMNs at the core network level is performed by signaling, i.e., by exchanging information between core networks. Optionally, the information exchanged is related to at least a part of the UEs processed by the involved PLMNs. Optionally, the information exchanged is related to at least a part of the UEs that are members of the V2X application layer group. For example, signaling at the core network level may correspond to exchanging information related to the following. · Information on the internal identification of UEs within the connected PLMN, and / or · An internal QoS policy applied to a UE within a connected PLMN, which enables the core network of the participating PLMN to pre-detect participants in the V2X application layer group by exchanging the internal QoS policy, and / or · Authorization for the UE to access the resource pool of the connected PLMN, and / or · Overall authorization policies and parameters for 5G ProSe direct detection and communication, and / or · Information related to the RAN, e.g., the status of the session for the UE in the connected PLMN, and / or a list of gNBs in the PLMN.

[0076] Core-level adjustment may further include exchanging information about QoS parameters between the CNs of the participating PLMNs. The information about QoS parameters may include priority levels, packet delay budgets, packet error rates, averaging windows (only for GBR and delay-critical GBR resource types), maximum data burst amounts (only for delay-critical GBR resource types), and / or QoS-related indications, e.g., "need for HARQ".

[0077] Core-level adjustment may further include exchanging information about group size between the access and mobility functions (AMF) of the participating PLMNs.

[0078] In an embodiment, the UE may issue a report from another UE via an existing PC5 link or, conversely, obtain it. The report may include information about group members. The information about group members may include the number of UEs in the group and / or identification information of group members and / or the connected PLMN.

[0079] In an embodiment, the same type of information regarding group members may be reported by a UE to a connected gNB via the Uu link, and further RAN level adjustment may be performed. RAN level adjustment may include different PLMN gNBs reporting or exchanging information such as identification of group members or the status of group communication between a group member and the connected gNB via the Xn link.

[0080] {Specific configuration and / or reconfiguration of physical resources} The configuration and / or reconfiguration of physical resources is an aspect of the proposed technology and is described herein.

[0081] To perform PC5 communication, it is necessary to know the resource pool configuration. UEs connected to the network may sometimes be notified of any resource pool reconfiguration determined by the network by means of RRC configuration or SIB signaling. Information regarding the configuration or reconfiguration may be transmitted to UEs of a given V2X application layer group by various means.

[0082] For example, information regarding the configuration or reconfiguration may be received by a first UE from its connected PLMN and then relayed to a second UE via the PC5 interface. The advantage of relaying via the PC5 interface is that it is simple because there is no need to define a new container compared to an existing PC5 link. However, it is also necessary to take a fairly large time margin between the time when the reconfiguration is determined and the time when the reconfiguration is applied. This is because the second UE needs to have sufficient time to acquire the information in order to avoid a radio link failure as a result of applying the reconfiguration. In this example, information regarding the configuration or reconfiguration is transmitted from one UE to another UE.

[0083] For example, information regarding configuration or reconfiguration may be sent directly by at least one transmitting gNB of the PLMNs involved to the UEs within a given V2X application layer group. The transmitting gNB has limited knowledge about the identification of the UEs within a given group. The information regarding configuration or reconfiguration may be transmitted, for example, via a group PDCCH message encoded by an identifier specific to a given group or an identifier specific to the type of service (such as a dedicated RNTI, etc.). The transmitting gNB, or another entity of the same PLMN, may further indicate specific dedicated resources to enable authorized UEs to respond to or acknowledge this message. This dedicated resource may be common, for example, to all UEs within a given group. In this example, the information regarding configuration or reconfiguration is transmitted at the RAN level.

[0084] For example, as described in the previous section, when knowledge about adjacent gNBs within a partnering PLMN is available, the information regarding configuration or reconfiguration may be sent through specific signaling via the Xn link between adjacent gNBs. In this example, the information regarding configuration or reconfiguration is transmitted through RAN level adjustment.

[0085] For example, at the core network level, a Policy Control Function (PCF) may cooperate with an Access and Mobility Management Function (AMF) and optionally with a Session Management Function (SMF) to report changes in QoS policies for one or more members of a given group. In this example, the information regarding configuration or reconfiguration is transmitted through core network level adjustment.

[0086] Although various possible means of transmitting information regarding configuration or reconfiguration have been described above, it should be noted that if the PLMNs involved are members of a network federation as described in nplcit10, this information exchange may be minimized.

[0087] {Known resource pool configuration or reconfiguration procedure} The configuration and / or reconfiguration of physical resources by the proposed technology may be combined with known configurations or reconfiguration procedures, and examples thereof will be described herein.

[0088] As an exemplary slot 300, one having a known format of 3-symbol PSCCH, 3-symbol PSSCH-DMRS, and PSFCH is shown in FIG. 3.

[0089] As disclosed in nplcit4, the resource pool may be configured or pre-configured for the UE separately from the transmission perspective and the reception perspective. Thereby, the UE can monitor the PSCCH and receive PSSCH transmissions in a resource pool other than the resource pool for transmission, so that it can attempt to receive transmissions made by other UEs in those pools.

[0090] The resources on which the PSSCH is transmitted may be scheduled or configured by the gNB (referred to as resource allocation mode 1), or may be determined through a sensing procedure autonomously performed by the transmitting UE (referred to as resource allocation mode 2).

[0091] The PSFCH may carry HARQ feedback via the sidelink from the UE that performs the transmission (hereinafter referred to as TxUE) to the UE that is the target receiver of the PSSCH transmission (hereinafter referred to as RxUE). The sidelink HARQ feedback may be in the form of the conventional ACK / NACK, or in the form of only NACK where nothing is transmitted when decoding is successful.

[0092] The time resources for the PSFCH may be configured or pre-configured for each resource pool to occur once per, for example, one, two, or four slots. The frequency and / or code resources may be implicitly derived from the resources used by the associated PSSCH transmission, together with the L1 identification information of the UE transmitting the PSSCH, or may be derived together with the identification information within the group of UEs transmitting the PSFCH if groupcast with ACK / NACK feedback is used.

[0093] {Known sidelink HARQ signaling} HARQ feedback is well described in the literature. As disclosed in nplcit4, NR-V2X may support HARQ feedback based on the transmission of ACK / NACK (or DTX) for sidelink unicast services and groupcast services, as well as a HARQ scheme with only NACKs specific to groupcast services.

[0094] Defining an operation with only NACKs for groupcast can potentially create a lower sidelink resource requirement when more RxUEs need to send feedback to the same TxUE. A typical use case is the extended sensor scenario. In this scenario, all UEs within a given radius receive the same sensor information from the TxUE, and retransmission occurs if any UE fails to decode successfully. Since such information is only relevant within a given radius around the TxUE (e.g., dozens or hundreds of meters around a road intersection), the transmission of only NACK feedback may be restricted to UEs within such a radius, and any UE beyond such a radius may be configured not to provide any HARQ feedback. The minimum range requirement for the service may be provided together with the relevant QoS parameters from the service layer.

[0095] For example, a single bit of sidelink HARQ feedback may be carried from the RxUE to its TxUE on the PSFCH. Also, when under the control of the gNB in resource allocation mode 1, the TxUE may notify the gNB via the PUCCH or PUSCH of the status of the sidelink HARQ feedback calculated in relation to a specific dynamic or configured grant to assist in the scheduling of sidelink resource retransmission and allocation.

[0096] {Specific authorization provisioning / cancellation} Authorization provisioning and / or cancellation are aspects of the proposed technique and are described herein.

[0097] The policy control function (PCF) of the core network of the involved PLMN may provision authorizations for establishing direct communication between UEs of the same V2X application layer group. These authorization provisions and cancellations may be in the form of updates to the V2X policies or V2X authorization parameters sent to the involved UEs.

[0098] These updates are triggered by various entities for various reasons.

[0099] For example, the service capabilities in the UE are indicated by the UE itself and serve as a trigger for the policy provisioning procedure in the PCF of the subscribed PLMN.

[0100] For example, when considering the movement of the UE, information indicating the movement of the UE and obtained from the AMF of the subscribed PLMN serves as another trigger for the transmission of updates by the PCF.

[0101] For example, a change in the subscription in the list of PLMNs that the UE is authorized to perform V2X communication via the PC5 reference point may be another additional trigger for the transmission of an update by the PCF. This is achieved, for example, by using UE policy association changes initiated by PCF procedures, as defined in clause 4.16.12.2 of TS 23.502.

[0102] For example, when a UE that is normally connected to the home PLMN (H-PLMN) roams and subscribes to the visited PLMN (V-PLMN), the subscription change that leads to an update of the service authorization parameters is transferred to the UE by the PCF of the H-PLMN (H-PCF) via the PCF of the V-PLMN (V-PCF).

[0103] {Exemplary embodiments} Next, refer to FIG. 2. FIG. 2 shows an exemplary communication method adapted to the exemplary communication system of FIG. 1 as a flowchart having several blocks (or logical instructions).

[0104] As described below, implementing the method of FIG. 2 involves various entities within the communication system, each processing logical instructions. As shown in FIG. 5, such entities may each include a processing circuit 500, which comprises a processing unit 502 configured to process such logical instructions. The processing unit may be operably connected to a memory 504 configured to store such logical instructions and a communication interface 506 with other such entities. The communication interface may be configured to transmit and receive information when such logical instructions are processed.

[0105] In block 202, the V2X-AS issues messages to at least one entity within PLMN-A and at least one entity within PLMN-B. Here, an entity within a PLMN is understood without distinction as an entity of the core network CN, or an entity of the radio access network (RAN), or a UE connected to the PLMN. The message is information for PLMN-A and PLMN-B about the need for inter-PLMN support represented by the V2X-AS. This inter-PLMN application support means the establishment of direct communication between UEs connected to different PLMNs and / or the establishment of direct communication between a UE connected to one PLMN and a node (gNB) of another PLMN.

[0106] In block 204, CN-A obtains information about a group of UEs within other PLMNs that require application support from PLMN-A.

[0107] This information may be obtained by transferring a list of UEs within other PLMNs that are authorized to access the V2X service.

[0108] Considering PLMN-B as an example of another PLMN, such a list may be obtained from the authorization obtained from the policy of the control function (PCF-B) of PLMN-B and from the data stored in the integrated data repository (UDR) of PLMN-B that stores the subscription information of the UEs connected to PLMN-B. Alternatively, as a potential future addition to the current 3GPP SA6 specifications, such a list may be obtained from the application activation layer in combination with the identification of the UEs within PLMN-B provided by the UDR of PLMN-B, as described in nplcit8. Another possibility for CN-A to obtain information about a group of UEs within another PLMN that requires application support from PLMN-A is applicable when PLMN-A and PLMN-B are members of the same operator federation. In this case, as another potential future addition to the current specifications, CN-A and CN-B may each register the authorized UEs with the federation manager of the operator federation, and this registration may trigger the exchange of information about the UEs within PLMN-A and PLMN-B between CN-A and CN-B via the GSMA / OPG east-west bound interface, as described in nplcit10.

[0109] Furthermore, the UEs within PLMN-A that receive messages from V2X-AS in block 202 may each notify their respective gNBs. This information is relayed to CN-A, and CN-A may then prepare a list of the UEs within PLMN-A that are authorized to access the V2X service. This may be equivalent to a list of the UEs within PLMN-A that require application support from other PLMNs. CN-A may then exchange (i.e., both send and receive) information about the UEs that require inter-PLMN application support with the CNs of other PLMNs. In some cases, the CN may be configured to exchange this information only with a restricted list of CNs of PLMNs.

[0110] In block 206, CN-A sets one or more authorizations for UEs within the participating PLMNs other than PLMN-A that require application support from PLMN-A. The authorizations set by CN-A may be provided to various entities, particularly the following entities. · RAN-A, · The CN of the participating PLMN, particularly the PCF of the participating PLMN, · The application enabling layer (which may forward the authorization to the participating PLMN), · If the participating PLMN is a member of the same federation as PLMN-A, the federation manager (in this case, the federation manager may disclose the authorization to the participating PLMN), etc.

[0111] The authorization set by CN-A permits access to specific physical resources within the physical resource pool reserved for PLMN-A, or to a restricted list of specific physical resources. For example, the authorization may permit access to sidelink PSFCH resources and / or dedicated reserved resources on the Uu link.

[0112] An example of physical resource utilization by the proposed technology is shown in FIG. 4. In the example of FIG. 4, the first UE 406 and the second UE 410 are connected to PLMN-A, and the third UE 408 is connected to PLMN-B. The first UE uses the data resource (PSCCH-A) within the licensed spectrum 402 of PLMN-A to send data messages to both the second UE and the third UE. Both the second UE and the third UE may respond specifically by using dedicated resources (e.g., PSFCH resources) within the licensed spectrum 402 of PLMN-A, but it is not permitted to use this dedicated resource for any other purpose or to use other resources within the licensed spectrum 402 of PLMN-A. Assuming a mutual relationship, the first UE and / or the second UE can also respond to the data message sent by the third UE by using dedicated data resources within the licensed spectrum 404 of PLMN-B, by using the data resources within the licensed spectrum of PLMN-B.

[0113] Various restrictions apply to the permitted access. For example, access is permitted for a limited number of UEs, only for a given application, for a limited time, etc.

[0114] CN-A may further provide any information regarding its resource configuration that is useful or required for a UE that needs application support from PLMN-A to effectively access specific resources or a list of specific resources related to the authorization set by CN-A.

[0115] The information regarding the resource configuration of CN-A may include information related to the following. · The resource pool structure within the authorized resource pool managed by PLMN-A, · The authorized gNBs within RAN-A, · The authorized geographical areas within the geographical coverage area of PLMN-A, · Timers related to the authorization period, ·Group-related identifiers for RAN handover, ·Others.

[0116] In block 208, UE-A then uses its PC5 interface to directly communicate with one or more UEs (collectively referred to as UE-X) that belong to the same UE group as UE-A and require application support from PLMN-A to communicate with UE-A.

[0117] The use of the PC5 interface may be based on the current specifications and the information obtained by UE-X regarding the authorized resource pool of PLMN-A.

[0118] UE-X obtains this information directly from, for example, gNB-A. As a possibility, gNB-A may broadcast this information in a SIB all at once. Another possibility to improve efficiency is for gNB-A to send group control messages such as group PDCCH to a specific RNTI (X-RNTI) representing UE-X. The RNTI may be pre-configured or set by an entity within PLMN-A and may be part of the information exchanged within block 206 when authorization is set.

[0119] If PLMN-A transfers this information in block 206, UE-X obtains this information from the gNB within its home PLMN.

[0120] UE-X may also obtain this information directly from UE-A, via PC5, or through a local detection process, such as a model (A) or model (B) detection process as described in 3GPP TS23.303 and 3GPP TS23.304.

[0121] UE-A may use a resource pool configured by PLMN-A as a transmission resource pool available for this type of service within the licensed spectrum of PLMN-A to send a unicast data message or a multicast data message to UE-X.

[0122] If UE-X receives the unicast message or multicast message defined above, UE-X may respond by using the permitted resources within the resource pool belonging to the licensed spectrum of PLMN-A by following the same procedures as the UE under PLMN-A. For example, if a UE under PLMN-A is permitted to respond to such a message with a PSFCH signal using a permitted resource pool dedicated to the PSFCH signal, UE-X may similarly be permitted to respond to such a message with a PSFCH signal using the same permitted resource pool.

[0123] However, UE-X may not be permitted to use other resources within the licensed spectrum of PLMN-A or to use the resources within the permitted resource pool for any other purpose other than responding to a unicast message or a multicast message. In particular, UE-X may not be permitted to transmit any data signals by using the resources within the licensed spectrum of PLMN-A.

[0124] For data transmission, interrelationships may be applied. That is, for example, UE-B may use the spectrum of PLMN-B to send a unicast message or a multicast message, and PLMN-B may further authorize UE-A to respond to such a message, in particular using a PSFCH signal within the licensed spectrum of PLMN-B, but without using a data signal.

[0125] UE-X may further send periodic reports to its connected gNB to notify that it is part of a group of UEs using PC5 communication between PLMNs.

[0126] UE-X may further send information related to the authorized resources to its connected gNB, and the connected gNB may further consider this information when scheduling resources for UE-X. In fact, for example, UE-X is not expected to perform transmissions simultaneously in both PLMN-A and its home PLMN.

[0127] UE-X may further periodically notify UE-A, via unicast or groupcast, about its connected gNB or its home PLMN. This information may be updated in the core network AMF or in a specific extension of the radio information API described in nplcit6.

[0128] In block 210, PLMN-A performs resource reconfiguration, for example, resource pool reconfiguration or reconfiguration related to PSFCH periodicity.

[0129] The resource reconfiguration may be determined by various network entities (entities other than UEs) within PLMN-A. Such entities are, for example, · gNBs within the RAN, · AMF or PCF nodes within the CN, · Application services, such as the radio network information service described in nplcit6, · The operator platform extension described in nplcit10, or · OAM nodes that execute long-term plans, and so on.

[0130] UE-A may be notified of any resource reconfiguration through known procedures such as RRC configuration procedures.

[0131] UE-X may be notified by various means.

[0132] UE-X may receive a notification from UE-A via PC5, which has the advantages of a moderately short waiting time and minimal changes to existing procedures. For example, a flag may be added to the RRC reconfiguration message sent to UE-A. This includes a command for relaying the configuration message to UE-X. UE-A may relay the RRC reconfiguration message to UE-X via the sidelink, via PC5 multicast, via PC5 unicast, or via PC5 RRC in the case of unicast between UE-A and UE-X. UE-X may send an ACK essential to UE-A to confirm the completion of the configuration transmission to UE-X, for example, via the Uu link.

[0133] Alternatively, gNB-A may directly notify UE-X of the resource reconfiguration, which has the advantage of a short waiting time. gNB-A may transmit the information regarding the reconfiguration in the SIB all at once, or may transmit a group control message such as a group PDCCH to a specific RNTI (X-RNTI) representing UE-X. X-RNTI may be pre-configured or set by an entity within PLMN-A and may be part of the information exchanged in block 206.

[0134] Alternatively, the UE-X may be notified of resource reconfiguration by each connected PLMN at the RAN level. Advantages include that, similar to the currently known RRC reconfiguration procedure, the latency is moderately short, and it is easy for each gNB to check the completion of the reconfiguration. Possible procedures for notifying the UE-X by each connected PLMN at the RAN level will be described here. Assume that the UE-X periodically reports each connected gNB (gNB-X) to the UE-A via PC5, rather than necessarily by using the spectrum of PLMN-A. gNB-A requests a report including a list of neighboring gNBs (collectively referred to as gNB-X) from the UE-A. Each of the neighboring gNBs has at least one connected UE configured to communicate with the UE-A using an inter-PLMN PC5 sidelink with a specific authorization set by CN-A. Alternatively, the UE-A may be configured to periodically send such a report to the gNB-A. gNB-A may notify the gNB-X about the reconfiguration. Each of the gNBs among the gNB-X may reconfigure any UE among the UE-X connected to the gNB. As a prerequisite, each of the gNB-X may hold an updated list of the connected UEs involved in the inter-PLMN PC5 sidelink, and the UE-X may periodically report their status for the inter-PLMN PC5 sidelink to each gNB.

[0135] Alternatively, UE-X may be notified of resource reconfiguration at the CN level by each connected PLMN. The RRC reconfiguration of UE-A may be triggered by a message from an entity in the CN of UE-X's home network (PLMN-X) to the corresponding entity in the CN of PLMN-A. For example, this message may be sent by the PCF of PLMN-X to the PCF of PLMN-A. Alternatively, the message may be sent between application enabling layers (AELs) or between operator platforms (OPs), rather than between PCFs. As a possible future addition to the current specification, the message may be actually sent by the operator platform (OP-X) of PLMN-X to the operator platform (OP-A) of PLMN-A via an east-west bound API between OP-X and OP-A, and further relayed to the RAN of PLMN-A via a southbound interface (SBI). Reconfiguration via the CN has the advantages of scalability and signaling reduction. Because multiple UEs connected to PLMN-A are reconfigured based on a single message exchanged between the PCFs, AELs, or OPs of PLMN-X and PLMN-A.

[0136] In block 212, the authorization for a given UE-B in UE-X to use the resources of PLMN-A is cancelled by V2X-AS and / or CN-A. Possible reasons for the cancellation include, for example, the disconnection of UE-B from PLMN-B due to being out of coverage or roaming to another PLMN.

[0137] If such authorization is cancelled by V2X-AS, V2X-AS specifically notifies UE-B of the cancellation, for example, directly via PC1 or indirectly by sending a message to UE-A via PC1 and then having UE-A notify UE-B via PC5.

[0138] If such authorization is revoked by CN-A or if such authorization is revoked by V2X-AS and V2X-AS further notifies the revocation to PLMN-A, there are various possible means for PLMN-A to directly or indirectly notify UE-B of the revocation.

[0139] For example, PLMN-A may instruct one or more specific gNBs to reconfigure their resource pools and / or to simultaneously transmit messages directly notifying UE-B of the revocation.

[0140] Alternatively, or in combination, UE-A may be notified of the revocation by PLMN-A, more specifically by its serving gNB, and may notify UE-B via PC5.

[0141] Alternatively, or in combination, PLMN-A may notify PLMN-B of the revocation, for example, by inter-PLMN communication at the core network level or RAN level. PLMN-B may notify UE-B of the revocation.

Claims

1. A method of communicating between a first network element connected to a first public land mobile network and a second network element connected to a second public land mobile network, wherein the second network element is not connected to the first public land mobile network, the method is related to an authorization for the second network element to access specific network resources of the first public land mobile network, the authorization enabling only the second network element to access the specific network resources for a specific use related to communication with the first network element, and the method starting the provisioning of the authorization, provisioning the authorization to the second network element in the first public land mobile network, and the second network element accessing the specific network resources of the first public land mobile network for the specific use, A method comprising at least one of the above elements.

2. Starting the provisioning of the authorization is performed in an application server that processes application layer clients running on the first network element and the second network element, or in a federation manager coupled to the first public land mobile network and the second public land mobile network, the federation manager detecting a service that includes an application server that processes application layer clients running on the first network element and the second network element, The method according to claim 1, performed based on the obtained application level information.

3. The method uses an indication that both the first network element and the second network element are members of the same group of network elements, and / or the method further includes forming and / or managing a group of network elements connected to different public land mobile networks, forming and / or managing the group of network elements is based on the collected data related to the network elements, and the collected data for a given network element Indication of physical location, Estimation of communication performance, Estimation of service quality sustainability, and Grouping information with at least one other network element connected to the same public land mobile network, The method according to claim 1 or 2, comprising at least one type of data among.

4. The method includes transmitting support information to the first public land mobile network and / or the second public land mobile network, and the support information is related to the authorization to be provisioned. The method according to any one of claims 1 to 3.

5. The support information related to the authorization to be provisioned is transmitted to the first public land mobile network and / or the second public land mobile network, The method includes performing network adjustment between the first public land mobile network and the second public land mobile network based on the support information. The method according to any one of claims 1 to 4.

6. The support information includes at least an indicator or request for support between public land mobile networks. The method according to claim 4 or 5.

7. The method includes detecting the second network element in the first public land mobile network by performing information exchange via the PC5 interface between the first network element and the second network element. The method according to any one of claims 1 to 6.

8. The method includes detecting the second network element in the first network element via the PC5 interface between the first network element and the second network element. The method according to any one of claims 1 to 6.

9. The specific application is to use the network resources of the first public land mobile network to transmit feedback to the first network element when the second network element is the intended recipient of the data packet in response to a data packet previously transmitted by the first network element. The method according to any one of claims 1 to 8.

10. A computer program comprising instructions which, when the computer program is executed by a processor, cause the processor to perform the method according to any one of claims 1 to 9. **Claim 11** An application server coupled to a communication system comprising a first network element connected to a first public land mobile network and a second network element connected to a second public land mobile network, wherein the second network element is not connected to the first public land mobile network, wherein each of the first network element and the second network element executes an application layer client, wherein the application server processes the application layer client, wherein the application server is configured to send application level information to an authorization provisioning start module, wherein the authorization provisioning start module is configured to start provisioning of authorization for the second network element to access specific network resources of the first public land mobile network based on the application level information, wherein the authorization enables only the second network element to access the specific network resources for a specific use related to communication with the first network element. **Claim 12** A federation manager in a communication system comprising a first network element connected to a first public land mobile network and a second network element connected to a second public land mobile network, wherein the second network element is not connected to the first public land mobile network, wherein each of the first network element and the second network element executes an application layer client, wherein the federation manager is connected to the first public land mobile network and the second public land mobile network, wherein the federation manager has detected a service including an application server that processes the application layer client. The federation manager is configured to send application-level information to an authorization provisioning start module, The authorization provisioning start module is configured to start provisioning of authorization for the second network element to access specific network resources of the first public land mobile network based on the application-level information, The authorization enables only the second network element to access the specific network resources for a specific use related to communication with the first network element, by the federation manager.

13. An authorization provisioning module in a communication system comprising a first network element connected to a first public land mobile network and a second network element connected to a second public land mobile network, wherein the second network element is not connected to the first public land mobile network, The authorization provisioning module is configured to provision authorization in the first public land mobile network for the second network element to access specific network resources of the first public land mobile network, The authorization enables only the second network element to access the specific network resources for a specific use related to communication with the first network element, by the authorization provisioning module.

14. A network element in a communication system, The communication system further includes a corresponding network element connected to a first public land mobile network, The network element is connected to a second public land mobile network, The network element is not connected to the first public land mobile network, The network element is configured to access specific network resources of the first public land mobile network for a specific use related to communication with the corresponding network element.

15. The network element according to claim 14, wherein the network element is a user equipment or a base station of the second public land mobile network.

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