Method and apparatus for providing multicast services

Abstract

The present disclosure relates to apparatuses, methods and computer programs for a system for providing multicast services. A technique comprising: receiving, at a session management function, information by which a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; and directing, towards a radio access network node, an indication of the plurality of multicast service areas; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to apparatuses, methods and computer programs, and in particular to apparatuses, methods and computer programs for a system for providing a multicast service. BACKGROUND

[0002] A multicast session provided via a radio access network to user equipment can be provided in a plurality of local service areas, each local service area comprising one or more cells operated by one or more nodes of the radio access network, with some service content being tailored to the local service area. A session management function managing the multicast session can provide information about the multicast session to the radio access network nodes. SUMMARY

[0003] A method comprising: receiving, at a session management function, information by which a plurality of multicast service areas for a multicast session managed by the session management function are identifiable; and directing an indication of the plurality of multicast service areas towards a radio access network node; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0004] The radio access network node can comprise a node identified as a target node for a handover of the user equipment.

[0005] The information can originate from the target node.

[0006] The method can comprise receiving the information in a target node message carried by a message from an access management function.

[0007] The information can originate from the access management function.

[0008] The method can comprise receiving the information in an access management function message carrying a message from the radio access network node.

[0009] The method can comprise receiving the information at the session management function in reply to a request from the session management function.

[0010] The method can comprise sending the request from the session management function in response to receiving a request from the access management function to join the multicast session from the user equipment.

[0011] The method can comprise sending the request from the session management function to the access management function.

[0012] The method can comprise directing the request to the radio access network node.

[0013] The method can comprise receiving the information at the session management function and a request to join the multicast session from the user equipment.

[0014] The information can be generated by the radio access network node in response to receiving a radio resource control message from the user equipment, the radio resource control message comprising an indicator indicating that the radio resource control message carries a request to join the multicast session; and the method can comprise receiving the information via the access management function.

[0015] The information can be generated by the access management function in response to receiving a next generation application protocol message from the radio access network node, the next generation application protocol message comprising an indicator indicating that the next generation application protocol message carries a request to join the multicast session.

[0016] The information can comprise a first tracking area and cell list, and the method can comprise identifying a plurality of multicast service areas from an intersection of the first tracking area and cell list and a second tracking area and cell list, the second tracking area and cell list belonging to a set of multicast service areas for the multicast session.

[0017] A method comprising: sending information from an access management function to a session management function, by which information a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; receiving an indication of the plurality of multicast service areas from the session management function; and forwarding the indication of the plurality of multicast service areas to a radio access network node; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0018] The method can comprise sending the information in response to receiving a path switch request from a target radio access network node.

[0019] The path switch request can comprise the information, and the method can further comprise forwarding the information received from the target radio access network node to the session management function.

[0020] The information can be comprised in a message carried by the path switch request, and the method can comprise including the carried message in a message to the session management function.

[0021] The method can comprise retrieving the information in response to receiving the path switch request, and including the retrieved information in a message to the session management function.

[0022] The method can comprise sending the information to the session management function in response to a request from the session management function.

[0023] The method can comprise retrieving the information in response to determining that a message received from the radio access network node carries a join request from a user equipment to join the multicast session; and including the retrieved information in a message to the session management function carrying the join request.

[0024] The determination can be based on an indicator included in a message carrying the join request by the radio access node.

[0025] The method can comprise receiving information in a message from the radio access network node, the message carrying a join request from the user equipment to join the multicast session.

[0026] A method comprising sending information from a radio access network node to a session management function, or to an access management function to forward to the session management function, by which information a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0027] The method can comprise sending the information to the session management function in a reply to a request from the session management function.

[0028] The method can comprise retrieving the information in response to determining that a radio resource control message received from the user equipment carries a join request from the user equipment to join the multicast session; and including the retrieved information in a message carrying the join request to the access management function.

[0029] The determination can be based on an indicator included in the radio resource control message by the user equipment.

[0030] The method can comprise retrieving the information in response to completing a handover of the user equipment, and including the information in a path switch request towards the session management function via the access management function.

[0031] A method comprising sending a radio resource control message to a radio access network node to forward to a session management function via an access management function, the radio resource control message carrying a join request to join a multicast session managed by the session management function, wherein the radio resource control message includes an indicator indicating that the carried message is a join request to join the multicast session.

[0032] The indicator can trigger the radio access node to forward the join request to the access management function together with information by which a plurality of multicast service areas for the multicast session is identifiable; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0033] The indicator can trigger the radio access node to forward the join request to the access management function together with an indicator triggering the access management function to forward the join request to the session management function, together with information by which a plurality of multicast service areas for the multicast session is identifiable; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0034] The radio resource control message can comprise information by which the plurality of multicast service areas for the multicast session can be identified; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0035] The information by which the plurality of multicast service areas can be identified can comprise information by which all multicast service areas associated with the radio access network node can be identified.

[0036] The information by which the plurality of multicast service areas can be identified can define areas associated with the radio access network node.

[0037] The information by which the plurality of multicast service areas can be identified can comprise at least one of: a list of tracking areas associated with the radio access network node; an identifier of the radio access network node; a list of cells associated with the radio access network node; a registration area identifier of user equipment served by the radio access network node.

[0038] The information by which the plurality of multicast service areas can be identified can define areas associated with a location of the user equipment.

[0039] The indication can be a context area.

[0040] An apparatus comprising: means for receiving information by which a plurality of multicast service areas for a multicast session managed by the apparatus can be identified; and means for directing an indication of the plurality of multicast service areas towards a radio access network node; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0041] The radio access network node can comprise a node identified as a target node for a handover of the user equipment.

[0042] The information can originate from the target node.

[0043] The apparatus can comprise means for receiving the information in a target node message carried by a message from an access management function.

[0044] The information can originate from the access management function.

[0045] The apparatus can comprise means for receiving the information in an access management function message carrying a message from the radio access network node.

[0046] The apparatus can comprise means for receiving the information in a reply to a request from the apparatus.

[0047] The apparatus can comprise means for sending the request to an access management function in response to receiving the request to join the multicast session from the user equipment.

[0048] The apparatus can comprise means for sending the request to an access management function.

[0049] The apparatus can comprise means for directing the request to a radio access network node.

[0050] The apparatus can comprise means for receiving the information and the request to join the multicast session from the user equipment.

[0051] The information can be generated by the radio access network node in response to receiving a radio resource control message from the user equipment, the radio resource control message comprising an indicator indicating that the radio resource control message carries the request to join the multicast session; and the apparatus can comprise means for receiving the information via an access management function.

[0052] The information can be generated by the access management function in response to receiving a next generation application protocol message from the radio access network node, the next generation application protocol message comprising an indicator indicating that the next generation application protocol message carries the request to join the multicast session.

[0053] The information can comprise a first tracking area and cell list, and the apparatus can comprise means for identifying a plurality of multicast service areas from an intersection of the first tracking area and cell list and a second tracking area and cell list, the second tracking area and cell list belonging to a set of multicast service areas for the multicast session.

[0054] An apparatus comprising means for sending information to a session management function, by which a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; means for receiving an indication of the plurality of multicast service areas from the session management function; and means for forwarding the indication of the plurality of multicast service areas to a radio access network node; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0055] The apparatus can comprise means for sending the information in response to receiving a path switch request from a target radio access network node.

[0056] The path switch request can comprise the information, and the apparatus can further comprise means for forwarding the information received from the target radio access network node to the session management function.

[0057] The information can be comprised in a message carried by the path switch request, and the apparatus can comprise means for including the carried message in a message to the session management function.

[0058] The apparatus can comprise means for retrieving the information in response to receiving the path switch request, and means for including the retrieved information in the message to the session management function.

[0059] The apparatus can comprise means for sending the information to the session management function in response to a request from the session management function.

[0060] The apparatus can comprise means for retrieving the information in response to determining that a message received from the radio access network node carries a join request from the user equipment to join the multicast session; and means for including the retrieved information in the message to the session management function carrying the join request.

[0061] The determination can be based on an indicator included in the message carrying the join request by the radio access node.

[0062] The apparatus can comprise means for receiving the information in a message from the radio access network node, the message carrying a join request from the user equipment to join the multicast session.

[0063] An apparatus comprising means for sending information to a session management function, or to an access management function to forward to the session management function, by which a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0064] The apparatus can comprise means for sending the information to the session management function in reply to a request from the session management function.

[0065] The apparatus can comprise means for retrieving the information in response to determining that a radio resource control message received from the user equipment carries a join request from the user equipment to join the multicast session; and means for including the retrieved information in the message to the access management function carrying the join request.

[0066] The determination can be based on an indicator included in the radio resource control message by the user equipment.

[0067] The apparatus can comprise means for retrieving the information in response to completion of a handover of the user equipment, and means for including the information in a path switch request towards the session management function via the access management function.

[0068] An apparatus comprising: means for sending, to a radio access network node configured to forward to a session management function via an access management function, a radio resource control message carrying a join request to join a multicast session managed by the session management function, wherein the radio resource control message comprises an indicator indicating that the carried message is a join request to join the multicast session.

[0069] The indicator can trigger the radio access node to forward the join request to the access management function together with information by which a plurality of multicast service areas for the multicast session are identifiable; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0070] The indicator can trigger the radio access node to forward the join request to the access management function together with an indicator triggering the access management function to forward the join request to the session management function together with information by which a plurality of multicast service areas for the multicast session are identifiable; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0071] The radio resource control message can comprise information by which a plurality of multicast service areas for the multicast session are identifiable; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0072] The information by which the plurality of multicast service areas are identifiable can comprise information by which all multicast service areas associated with the radio access network node are identifiable.

[0073] The information by which the plurality of multicast service areas are identifiable can define an area associated with the radio access network node.

[0074] The information by which the plurality of multicast service areas are identifiable can comprise at least one of: a list of tracking areas associated with the radio access network node; an identifier of the radio access network node; a list of cells associated with the radio access network node; a registration area identifier of user equipment served by the radio access network node.

[0075] The information by which the plurality of multicast service areas are identifiable can define an area associated with a location of the user equipment.

[0076] The indication can be a context area.

[0077] An apparatus comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform: managing a multicast session; receiving information by which a plurality of multicast service areas for the multicast session are identifiable; and directing an indication of the plurality of multicast service areas towards a radio access network node; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0078] The radio access network node can comprise a node identified as a target node for a handover of the user equipment.

[0079] The information can originate from the target node.

[0080] The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to receive the information in a target node message carried by a message from an access management function.

[0081] The information can originate from the access management function.

[0082] The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to receive the information in an access management function message carrying a message from the radio access network node.

[0083] The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to receive the information in a reply to a request from a session management function.

[0084] The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to send the request in response to receiving a request from the user equipment to join the multicast session from an access management function.

[0085] The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to send the request to the access management function.

[0086] The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to direct the request to the radio access network node.

[0087] The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to receive the information and the request from the user equipment to join the multicast session.

[0088] The information can be generated by the radio access network node in response to receiving a radio resource control message from the user equipment, the radio resource control message comprising an indicator indicating that the radio resource control message carries a request to join a multicast session; and the at least one memory and computer program code can be configured to, with the at least one processor, cause the apparatus to receive the information via an access management function.

[0089] The information can be generated by the access management function in response to receiving a next generation application protocol message from the radio access network node, the next generation application protocol message comprising an indicator indicating that the next generation application protocol message carries a request to join a multicast session.

[0090] The information can comprise a first tracking area and cell list, and the at least one memory and computer program code can be configured to, with the at least one processor, cause the apparatus to identify a plurality of multicast service areas from an intersection of the first tracking area and cell list and a second tracking area and cell list, the second tracking area and cell list belonging to a set of multicast service areas for a multicast session.

[0091] An apparatus comprising at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform: sending information to a session management function, by which a plurality of multicast service areas for a multicast session managed by the session management function are identifiable; receiving an indication of the plurality of multicast service areas from the session management function; and forwarding the indication of the plurality of multicast service areas to a radio access network node; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0092] The at least one memory and computer program code can be configured to, with the at least one processor, cause the apparatus to send the information in response to receiving a path switch request from a target radio access network node.

[0093] The path switch request can comprise the information, and the at least one memory and computer program code can be configured to, with the at least one processor, cause the apparatus to forward the information received from the target radio access network node to the session management function.

[0094] The information can be comprised in a message carried by the path switch request, and the at least one memory and computer program code can be configured to, with the at least one processor, cause the apparatus to include the carried message in a message to the session management function.

[0095] The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to retrieve the information in response to receiving the path switch request and include the retrieved information in a message to the session management function.

[0096] The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to send the information to the session management function in response to a request from the session management function.

[0097] The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to retrieve the information in response to determining that a message received from the radio access network node carries a join request from the user equipment to join the multicast session; and include the retrieved information in a message to the session management function carrying the join request.

[0098] The determination can be based on an indicator included in the message carrying the join request by the radio access node.

[0099] The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to receive the information in a message from the radio access network node, the message carrying a join request from the user equipment to join the multicast session.

[0100] An apparatus comprising at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform: sending information to a session management function, or to an access management function to forward to the session management function, by which information a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0101] The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to send the information to the session management function in reply to a request from the session management function.

[0102] The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to retrieve the information in response to determining that a radio resource control message received from the user equipment carries a join request from the user equipment to join the multicast session; and include the retrieved information in a message to the access management function carrying the join request.

[0103] The determination can be based on an indicator included in the radio resource control message by the user equipment.

[0104] The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to retrieve the information and include the information in a path switch request towards a session management function via an access management function in response to completing a handover of the user equipment.

[0105] An apparatus comprising at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform: sending, to a radio access network node to forward via an access management function to a session management function, a radio resource control message carrying a join request to join a multicast session managed by the session management function, wherein the radio resource control message comprises an indicator indicating that the carried message is a join request to join the multicast session.

[0106] The indicator can trigger the radio access node to forward the join request to the access management function together with information by which a plurality of multicast service areas for the multicast session is identifiable; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0107] The indicator can trigger the radio access node to forward the join request to the access management function together with an indicator triggering the access management function to forward the join request to the session management function together with information by which a plurality of multicast service areas for the multicast session is identifiable; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0108] The radio resource control message can comprise information by which a plurality of multicast service areas for the multicast session is identifiable; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0109] The information by which the plurality of multicast service areas is identifiable can comprise information by which all multicast service areas associated with the radio access network node are identifiable.

[0110] The information by which the plurality of multicast service areas is identifiable can define an area associated with the radio access network node.

[0111] The information by which the plurality of multicast service areas is identifiable can comprise at least one of: a list of tracking areas associated with the radio access network node; an identifier of the radio access network node; a list of cells associated with the radio access network node; a registration area identifier of user equipment served by the radio access network node.

[0112] The information by which the plurality of multicast service areas is identifiable can define an area associated with a location of the user equipment.

[0113] The indication can be a context area.

[0114] An apparatus comprising: receiving circuitry to receive information by which a plurality of multicast service areas for a multicast session managed by the apparatus is identifiable; and directing circuitry to direct an indication of the plurality of multicast service areas towards a radio access network node; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0115] An apparatus comprising: sending circuitry to send, to a session management function, information by which a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; receiving circuitry to receive, from the session management function, an indication of the plurality of multicast service areas; and forwarding circuitry to forward the indication of the plurality of multicast service areas to a radio access network node; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0116] An apparatus comprising: sending circuitry to send, to a session management function, or to an access management function to forward to the session management function, information by which a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0117] An apparatus comprising: sending circuitry to send, to a radio access network node to forward to a session management function via an access management function, a radio resource control message carrying a join request to join a multicast session managed by the session management function, wherein the radio resource control message comprises an indicator indicating that the message carried is a join request to join the multicast session.

[0118] A computer readable medium comprising program instructions stored thereon for performing: receiving, at a session management function, information by which a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; and directing an indication of the plurality of multicast service areas towards a radio access network node; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0119] A computer readable medium comprising program instructions stored thereon for performing: sending, from an access management function, information to a session management function, by which a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; receiving, from the session management function, an indication of the plurality of multicast service areas; and forwarding, to a radio access network node, the indication of the plurality of multicast service areas; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0120] A computer readable medium comprising program instructions stored thereon for performing: sending, from a radio access network node, information to a session management function, or to an access management function for forwarding to the session management function, by which a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0121] A computer readable medium comprising program instructions stored thereon for performing: sending, to a radio access network node for forwarding to a session management function via an access management function, a radio resource control message carrying a join request to join a multicast session managed by the session management function, wherein the radio resource control message comprises an indicator indicating that the carried message is a join request to join the multicast session.

[0122] A computer program comprising computer executable instructions which, when run on at least one processor, are configured to cause an apparatus at least to: receive, at a session management function, information by which a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; and direct, towards a radio access network node, an indication of the plurality of multicast service areas; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0123] A computer program comprising computer executable instructions which, when run on at least one processor, are configured to cause an apparatus at least to: send, from an access management function, information to a session management function, by which a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; receive, from the session management function, an indication of the plurality of multicast service areas; and forward, to a radio access network node, the indication of the plurality of multicast service areas; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0124] A computer program comprising computer executable code which, when run on at least one processor, is configured to cause an apparatus at least to: send, from a radio access network node, to a session management function, or to an access management function to forward to the session management function, information by which a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0125] A computer program comprising computer executable code which, when run on at least one processor, is configured to cause an apparatus at least to: send, to a radio access network node to forward via an access management function to a session management function, a radio resource control message carrying a join request to join a multicast session managed by the session management function, wherein the radio resource control message comprises an indicator indicating that the carried message is a join request to join the multicast session.

[0126] A non-transitory computer readable medium comprising program instructions stored thereon for performing: receiving, at a session management function, information by which a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; and directing an indication of the plurality of multicast service areas towards a radio access network node; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0127] A non-transitory computer readable medium comprising program instructions stored thereon for performing: sending, from an access management function, to a session management function, information by which a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; receiving, from the session management function, an indication of the plurality of multicast service areas; and forwarding the indication of the plurality of multicast service areas to a radio access network node; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0128] A non-transitory computer readable medium comprising program instructions stored thereon for performing: sending, from a radio access network node, to a session management function, or to an access management function to forward to the session management function, information by which a plurality of multicast service areas for a multicast session managed by the session management function is identifiable; wherein the plurality of multicast service areas is a subset of a set of multicast service areas for the multicast session.

[0129] A non-transitory computer readable medium comprising program instructions stored thereon for performing: sending, to a radio access network node configured to forward to a session management function via an access management function, a radio resource control message carrying a join request to join a multicast session managed by the session management function, wherein the radio resource control message comprises an indicator indicating that the carried message is a join request to join the multicast session.

[0130] In the foregoing, a number of different aspects have been described. It should be appreciated that other aspects can be provided by a combination of any two or more of the aspects described above.

[0131] Various other aspects are also described in the following detailed description and the appended claims. BRIEF DESCRIPTION OF DRAWINGS

[0132] Some example embodiments will now be described in greater detail below, by way of example only, with reference to the following examples and drawings, in which:

[0133] Figure 1 An example system to which the embodiments can be applied is illustrated;

[0134] Figure 2 A representation of the components of a 5G system used in the example embodiments is shown;

[0135] Figure 3 A representation of an example of operation at the components of Figure 2 in accordance with example embodiments is shown;

[0136] Figure 4 A representation of another example of operation at the components of Figure 2 in accordance with example embodiments is shown;

[0137] Figure 5 A representation of another example of operation at the components of Figure 2 in accordance with example embodiments is shown;

[0138] Figure 6 A representation of another example of operation at the components of Figure 2 in accordance with example embodiments is shown;

[0139] Figure 7 A representation of another example of operation at the components of Figure 2 in accordance with example embodiments is shown;

[0140] Figure 8 A representation of an example of an apparatus for implementing operation at a user equipment or RAN node in accordance with some example embodiments is shown;

[0141] Figure 9An example of a representation of an apparatus for implementing operations at a core network node is shown in accordance with some example embodiments; and

[0142] Figure 10 An example of a representation of a non-volatile storage medium is shown. DETAILED DESCRIPTION

[0143] The following description of example embodiments refers to systems (user equipment, RAN nodes, core network nodes) operating in accordance with certain 3GPP protocols, such as 5G protocols, but the underlying techniques are applicable to systems operating in accordance with other protocols as well, such as more evolved 3GPP protocols.

[0144] In the following, different example embodiments will be described using, as an example of an access architecture to which the embodiments can be applied, a radio access architecture based on Long Term Evolution Advanced (LTE-A) or New Radio (NR, 5G), but the embodiments are not limited to this architecture. With

[0145] Figure 1 An example of a simplified system architecture is depicted, only some elements and functional entities being shown, all being logical units whose implementation can differ from what is shown. Figure 1 The connections in are logical connections; actual physical connections can be different. It is apparent to a person skilled in the art that a system typically also comprises other functions and structures necessary for the operation in addition to those shown in Figure 1

[0146] However, the embodiments are not limited to the system given as an example but a person skilled in the art can apply the solution to other communication systems providing the necessary properties.

[0147] Figure 1 An example of a simplified system architecture is depicted, only some elements and functional entities being shown, all being logical units whose implementation can differ from what is shown.

[0148] Figure 1 ​​​Devices 100 and 102 are shown. Devices 100 and 102 are configured to wirelessly connect with a node 104 over one or more communication channels. Node 104 is additionally connected to a core network 106. In one example, node 104 can be an access node such as a (e / g)NodeB serving device in a cell. In one example, node 104 can be a non-3GPP access node. The physical link from a device to a (e / g)NodeB is called uplink or reverse link and the physical link from the (e / g)NodeB to the device is called downlink or forward link. It should be appreciated that a (e / g)NodeB or functionality thereof can be implemented by using any node, host, server or access point etc. entity suitable for such a use.

[0149] A communication system typically comprises more than one (e / g)NodeB, in which case the (e / g)NodeBs can also be configured to communicate with one another over links designed for the purpose, either wired or wireless. These links can be used for signalling purposes. A (e / g)NodeB is a computing device configured to control the radio resources of the communication system it is coupled to. A NodeB can also be referred to as a base station, an access point or any other type of interfacing device including a relay able to operate in a wireless environment. A (e / g)NodeB includes or is coupled to a transceiver. From the transceiver of the (e / g)NodeB, a connection is provided to an antenna unit that establishes bi-directional radio links to devices. The antenna unit can comprise multiple antennas or antenna elements. The (e / g)NodeB is additionally connected to a core network 106 (CN or Next Generation Core NGC). Depending on the technology deployed, the (e / g)NodeB is connected to a serving and packet data network gateway (S-GW + P-GW) or a user plane function (UPF) for routing and forwarding user data packets and for providing devices with access to one or more external packet data networks, and to a mobile management entity (MME) or access mobility management function (AMF) for controlling devices' access and mobility.

[0150] An exemplary embodiment of a device is a subscriber unit, user apparatus, user equipment (UE), user terminal, terminal device, mobile station, mobile device, etc.

[0151] A device generally refers to a mobile or stationary device (e.g., a portable or non-portable computing device) including wireless mobile communication devices operating with or without a

[0152] The device illustrates a type of apparatus to which resources on the air interface are allocated and assigned, and thus any of the features described herein for a device can be implemented with a corresponding apparatus, such as a relay node. An example of such a relay node is a Layer 3 relay towards a base station (self-backhauled relay). The device (or in some embodiments a Layer 3 relay node) is configured to perform one or more of the functionalities of a user equipment.

[0153] The various techniques described herein can also be applied to a cyber-physical system (CPS) (a system of collaborating computational elements controlling physical entities). CPS can enable the implementation of cyber physical systems whose physical and cyber components are deeply intertwined and strongly affect each other’s behavior. A cyber-physical system can be understood as a system of collaborating computational elements controlling physical entities. Mobile cyber-physical systems (where the physical system in question has inherent mobility) are a subcategory of cyber-physical systems whose physical system has inherent mobility. Examples of mobile physical systems include mobile robots and electronic vehicles.

[0154] Moreover, while an apparatus has been depicted as a single entity, different units, processors and / or memory units (not all shown in Figure 1

[0155] ​​5G supports the use of multiple input multiple output (MIMO) antennas, many more base stations or nodes than LTE (the so-called concept of small cell), including macro sites operating in co-operation with smaller stations and employing various radio technologies, depending on service needs, use cases and / or available spectrum. 5G mobile communications supports a wide range of use cases and related applications including video streaming, augmented reality, different ways of data sharing and various forms of machine type applications such as (massive) machine type communications (mMTC), including vehicular safety, different sensors and real-time control. 5G is expected to have multiple radio interfaces, e.g. below 6GHz or above 24 GHz, cmWave and mmWave, and can also be integrated with the existing legacy radio access technologies, such as LTE. At least in the early phase, the integration with LTE can be implemented as a system where macro coverage is provided by LTE and 5G radio interfaces access from small cells that are aggregated to LTE. In other words, 5G plans to support both inter-RAT operability, such as LTE-5G, and inter-RI operability (inter-radio interface operability), such as below 6GHz - cmWave, 6 or above 24 GHz - cmWave and mmWave. One of the concepts considered for use in 5G networks is network slicing, where multiple independent and dedicated virtual sub-networks (network instances) can be created within the same infrastructure to run services that have different requirements on latency, reliability, throughput and mobility.

[0156] The current architecture in LTE networks is fully distributed in radio and fully centralized in the core network. The low latency applications and services in 5G require bringing the content close to the radio, resulting in local break out and multi-access edge computing (MEC). 5G enables analytics and knowledge generation to occur at the data source. This approach requires leveraging resources that can not have persistent connectivity to the network, such as laptops, smartphones, tablets and sensors. MEC provides a distributed computing environment for application and service hosting. It also has the ability to store and process content in close proximity to the cellular subscriber for faster response time. Edge computing covers a wide range of technologies such as wireless sensor networks, mobile data acquisition, mobile signature analysis, cooperative distributed peer-to-peer ad hoc networking and processing can also be categorized as local cloud / fog computing and grid / mesh computing, dew computing, mobile edge computing, cloudlet, distributed data storage and retrieval, self-healing networks, remote cloud services, augmented reality and virtual reality, data caching, Internet of Things (massive connectivity and / or latency critical), critical communications (autonomous vehicles, traffic safety, real-time analytics, time-critical control, healthcare applications).

[0157] The communication system is also able to communicate with other networks 112, such as a public switched telephone network, or a VoIP network, or the Internet, or proprietary networks, and to exploit services provided by them. The communication system can also be able to support the use of cloud services, e.g. at least part of the core network operations can be carried out as a cloud service (this is depicted in Figure 1 the middle by "cloud" 114). The communication system can further include a central control entity, etc. providing facilities for networks of different operators to cooperate, e.g. in spectrum sharing.

[0158] By exploiting network function virtualization (NFV) and software defined networking (SDN), edge cloud technologies can be brought into the radio access network (RAN). Using edge cloud technologies can mean that at least part of the radio access node operations are carried out in a server, host or node operationally coupled to a remote radio head or base station comprising radio parts. Node operations can also be distributed among a plurality of servers, nodes or hosts. The application of cloud RAN architecture enables RAN real-time functions to be carried out at or near the remote antenna site (in a distributed unit, DU 108), and non-real-time functions to be carried out in a centralized manner (in a centralized unit, CU 110).

[0159] It should also be understood that the distribution of labor between core network operations and base station operations can be different from that of the LTE or even non-existent. Some other technological advancements that can be used are big data and all-IP, which can change the way networks are built and managed. 5G (or New Radio, NR) networks are designed to support multiple hierarchies, where MEC servers can be placed between the core and the base station or nodeB (gNB). It should be appreciated that MEC can also be applied to 4G networks.

[0160] 5G can also leverage satellite communication for enhanced or supplemental coverage of 5G services - for example by providing backhauling. Possible use cases include the provisioning of service continuity for machine-to-machine (M2M) or Internet of Things (IoT) devices or passengers on board of vehicles, mobile broadband (MBB), or ensuring service availability for critical communications, and future railway / maritime / aeronautical communications. Satellite communication can leverage Geostationary Earth Orbit (GEO) satellite systems, but also Low Earth Orbit (LEO) satellite systems, notably mega-constellations (systems in which hundreds of (nano)satellites are deployed). Each satellite in a mega-constellation can cover several satellite-enabled network entities creating ground cells. Ground cells can be created by ground relay nodes or by gNBs, located on the ground or in a satellite.

[0161] The skilled person will appreciate that the depicted system is merely an example of a part of a radio access system, and in practice the system can comprise multiple (e / g)NodeBs, the device can access multiple radio cells, and the system can further comprise other apparatus such as physical layer relay nodes or other network elements. At least one of the (e / g)NodeBs can be a home (e / g)NodeB. In addition, in the geographical area of the radio communication system, multiple radio cells of different kinds can be provided as well as multiple radio cells. The radio cells can be macro cells (or umbrella cells), which are large-sized cells typically with a diameter of up to tens of kilometers, or they can be smaller cells such as micro cells, femto cells, or pico cells. Figure 1 The (e / g)NodeBs can provide any kind of these cells. The cellular radio system can be implemented as a multi-tier network comprising multiple kinds of cells. Typically, in a multi-tier network one access node provides one or more cells of one kind, and thus multiple (e / g)NodeBs are needed to provide such a network structure.

[0162] To meet the need to improve the deployment and performance of communication systems, the concept of a "plug and play" (e / g)NodeB has been introduced. Typically, a network capable of using "plug and play" (e / g)NodeBs comprises, in addition to a home (e / g)NodeB (H(e / g)nodeB), a home nodeB gateway or HNB-GW (not shown in Figure 1 The HNB gateway (HNB-GW), which is typically installed within the operator's network, can aggregate traffic from a large number of HNBs back to the core network.

[0163] Figure 2 A representation of 3GPP 5G system components used in the example embodiments is shown. This Figure 2 The following description focuses on an example of providing multicast or broadcast services (MBS) via a 5G system, but the techniques are also applicable to providing MBS via other systems such as, for example, more evolved 3GPP systems. For ease of explanation, Figure 2 A small number of nodes are shown, but a 5G system can comprise multiple nodes implementing access management functionality, multiple nodes implementing session management functionality, and multiple nodes implementing user plane functionality. In this example, the term "user equipment" herein refers to any device, apparatus, or component implementing user equipment functionality; and can include, for example, a vehicle or other machine implementing UE functionality.

[0164] Data for a multicast session is provided from a data network 206 to multiple user equipment (UEs) 100 (which can comprise, for example, vehicles or other machines implementing UE functionality) via nodes 204 implementing user plane functionality and one or more radio access network nodes (base stations gNB) 104.Figure 1 The radio access network node can for example comprise Figure 1 the node 104 in

[0165] A multicast session for a location dependent multicast service can be provided in a set of local service areas, where some content is tailored to respective local service areas. A local service area can comprise one or more cells forming a subset of all cells operated by nodes of the radio access network.

[0166] For example, a local service area can be defined by a list of cells (operated by one or more gNBs 104 of the radio access network) or a respective list of tracking areas (TAs). A TA is a group of cells (operated by one or more gNBs 104 of the radio access network) to facilitate searching for UEs on the network without excessive signaling.

[0167] A location dependent multicast session in a local service area is identified by a common session ID (referred to as MBS session ID) for the entire set of service areas of the multicast session and a zone session ID specific to the local service area. The UE 100 only knows the MBS session ID. The UE 100 includes the MBS session ID in a join request to join the multicast session.

[0168] The entry point for a multicast session for a location dependent multicast service can change depending on the local service area (zone session ID). The entry point for a multicast session (identified by a MBS session ID) for one local service area can be different from the entry point for the same multicast session (identified by the MBS session ID) for another local service area. Similarly, the node implementing the session management functionality and / or the user plane functionality can change depending on the local service area (zone session ID). The node implementing the session management functionality for a multicast session (identified by a MBS session ID) for one local service area can be different from the node implementing the control plane session management functionality for the same multicast session (identified by the MBS session ID) for another local service area; and / or the node implementing the user plane functionality for a multicast session for one local service area can be different from the node implementing the user plane functionality for the same multicast session (identified by the MBS session ID) for another local service area.

[0169] As described below with respect to various example embodiments, the session management function managing the multicast session can provide information to the gNB 104 about the local service area for the multicast session.

[0170] Figure 3 A representation of an example of operation at components of Figure 2 is shown in accordance with example embodiments.

[0171] The gNB 104b has been identified as the target gNB for a handover of the UE 100 that has joined a location dependent multicast session.

[0172] The target gNB 104b sends a path switch request message to the AMF 200 (operation 300). The path switch request transfer IE (N2 SM (Session Management) container used to exchange information between the gNB 104b and the SMF 202 transparently to the AMF 200) carried by the path switch request message includes a list of TAs supported by the target gNB 104b.

[0173] The path switch request is a request to move the tunnel from the source gNB (serving gNB) 104a to the target gNB 104b and to inform the AMF of the change of serving gNB for the UE. Once the path switch request is acknowledged, data can flow from the UE 100 through the target node 104b to the prescribed UPF.

[0174] The AMF 200 forwards the path switch request transfer container to the SMF 202 in an Nsmf request message (operation 302).

[0175] The SMF 202 derives a context area for the target gNB 104b (hereinafter referred to as an MBS context area) based on the list of TAs included in the received path switch request transfer container (operation 304). The MBS context area selectively includes a list of local service areas (identified by a respective area session ID) mapped to the list of TAs received at the SMF. The MBS context area does not include the full set of local service areas for the multicast session across the PLMN; the MBS context area identifies a subset of the full set. Each local service area is expressed and known at the SMF 202 as a list of tracking area identifiers (TAIs) and cells. The MBS context area includes the intersection of: (a) the TAs received at the SMF 202 in the Nsmf request message, and (b) the set of TAs and cells that define the full set of local service areas for the multicast session. The MBS context area = a list of (area session ID, (list of TAs and cells)).

[0176] The SMF 202 sends the MBS context area for the target gNB 104b to the AMF 200 for forwarding to the target gNB (operation 306). The SMF 202 includes the MBS context area for the target gNB 104 in the path switch request acknowledge N2 SM carried by the Nsmf response message to the AMF 200.

[0177] The AMF 200 sends the path switch request N2 SM carried by the received Nsmf response message to the target gNB 104b (operation 308).

[0178] Figure 4 A representation of another example of operation at components of Figure 2 is shown in accordance with another example embodiment. This example is the same as the Figure 4 example except that the target eNB 104 does not include the list of TAs supported by the target gNB in the path switch request transfer container (which is included in the path switch request message sent to the AMF 200). Figure 3 Instead, in response to receiving the path switch request from the target gNB 104b, the AMF 200 retrieves the list of TAs supported by the target gNB 104b from the AMF memory.

[0179] Referring to Figure 4 : The target gNB 104b sends a path switch request message to the AMF 200 that includes a path switch request transfer container for forwarding from the AMF 200 to the SMF 202 (operation 400). The path switch request transfer container does not include a list of TAs supported by the target gNB 104b.

[0180] In response to receiving the path switch request from the target gNB 104b, the AMF 200 retrieves the list of TAs supported by the target gNB from the AMF memory (previously received by the AMF 200 during an NG-RAN setup procedure) (operation 402).

[0181] The AMF 200 includes the retrieved list of TAs supported by the target gNB 104b in an Nsmf request message that carries the path switch request transfer container to the SMF 202 (operation 404).

[0182] Subsequent operations 406, 408, and 410 are the same as operations 304, 306, and 308, respectively, of the example of Figure 3 .

[0183] Figure 5 A representation of another example of operation at components of Figure 2 is shown in accordance with another example embodiment.

[0184] Figure 5 The example of involves a location-dependent multicast session to which the UE 100 has not yet joined.

[0185] The UE 100 sends a request to join the multicast session (operation 500). The NAS join request specifies the MBS session ID for the location-dependent multicast session. The UE 100 sends the NAS join request to the AMF 200 for forwarding by the serving gNB 104a.

[0186] The AMF 200 forwards the received NAS join request to the SMF 202 that manages the identified multicast session (operation 502). In more detail, the AMF 200 sends an Nsmf Request to the SMF 202 carrying the received NAS join request.

[0187] In response to receiving the NAS join request, the SMF 202 sends an Nsmf Request to the AMF 200 carrying an N2 SM Location Query message associated with the UE for forwarding by the AMF 200 to the serving gNB 104a (operation 504).

[0188] In response to receiving the location query message from the AMF 200, the serving gNB 104a sends a location query response to the AMF 200 including a list of TAs supported by the serving gNB 104b for forwarding to the SMF 202 (operation 506). The AMF 200 sends an Nsmf Response to the SMF 202 carrying the location query response received from the serving gNB 104a.

[0189] The SMF 202 derives the MBS context area for the serving gNB 104a based on the list of TAs included in the location query response from the serving gNB 104a via the AMF 200 (operation 508). This operation 508 is the same as Figure 3 The operation 304 of the example.

[0190] The SMF 202 includes the derived MBS context area for the serving gNB 104a in a PDU Session Modification Request Transfer container for forwarding by the AMF 200 to the serving gNB 104a. The SMF 202 includes the PDU Session Modification Request Transfer in an Nsmf Response to the AMF 200 (operation 510).

[0191] The AMF 200 forwards the MBS context area for the serving gNB 104 within a PDU Session Modification Request (or PDU Session Establishment Request) message to the serving gNB 104a (operation 512).

[0192] Figure 6 A representation of another example of operation at components of Figure 2 is shown. This Figure 6 example is the same as Figure 5The example is the same except that the SMF 202 obtains the list of TAs supported by the serving gNB 104a from the AMF 200 without involving the serving gNB 104a.

[0193] Figure 6 The example operations 600 and 602 are the same as Figure 5 The example operations 500 and 502 are the same.

[0194] In response to receiving the NAS join request, the SMF 202 sends an Nsmf Request carrying a N2 SM Location Query message to the AMF 200 (operation 604).

[0195] In response to receiving the Location Query message, the AMF 200 retrieves the list of TAs supported by the serving gNB 104a from AMF storage (previously received by the AMF 200 via the NG-RAN establishment procedure) (operation 606).

[0196] The AMF 200 provides the retrieved list of TAs supported by the serving gNB 104a to the SMF 202. In more detail, the AMF 200 includes the retrieved list of TAs in an Nsmf Response message in reply to the Nsmf message received from the SMF 202 (operation 608).

[0197] Figure 6 The example operations 610, 612, and 614 are the same as Figure 5 The example operations 508, 510, and 512 are the same.

[0198] Figure 7 A representation of another example of operation at components of Figure 2 is shown.

[0199] The UE 100 sends a NAS join request to join a location-dependent multicast session (operation 700). The NAS join request specifies an MBS session ID for the multicast session. In this Figure 7 In this example, the NAS join request is carried by an RRC setup complete message. The UE 100 sends the NAS join request to the AMF 200 for forwarding by the serving gNB 104a, and from the AMF 200 to the SMF 202 that manages the established PDU session for the multicast session. The RRC setup complete message at 700 includes a join indicator that is relayed by the gNB at 702 to trigger the AMF 200 to provide the list of TAs supported by the serving gNB 104a to the SMF 202 when forwarding the NAS join request to the SMF 202.

[0200] The serving gNB 104a forwards the NAS join request and the join indicator along with an indication of the cell ID of the cell serving the UE 100 to the AMF 200 (operation 702). In more detail, the serving gNB 104a includes the NAS join request, the join indicator, and the serving cell ID in a NGAP Uplink NAS Transport message to the AMF 200.

[0201] In response to receiving the NGAP Uplink NAS Transport message and detecting the join indicator, the AMF 200 retrieves from the AMF memory the list of TAs supported by the serving gNB (previously received by the AMF 200 as part of the NG-RAN setup procedure) (operation 704).

[0202] When forwarding the NAS join request to the SMF 202, the AMF 200 provides the retrieved list of TAs supported by the serving gNB 104a to the SMF 202 at 706. In more detail: the AMF 200 includes the retrieved list of TAs supported by the serving gNB 104a in a Nsmf_ Request message carrying the NAS join request to the SMF 202.

[0203] Figure 7 The example operations 708, 710, and 712 are also the same as the above-described Figure 5 Example operations 508, 510, and 512, respectively.

[0204] According to Figure 7 An example variant: the RRC Setup Complete message carrying the join request includes an indicator that triggers the gNB 104 to retrieve from the gNB memory the list of TAs supported by the TAs and to forward the join request and the list of TAs supported by the gNB 104 to the AMF 200 for forwarding to the SMF 202. This variant is otherwise the same as the Figure 7 Example.

[0205] In each of the examples of Figures 3 to 7 In each of the examples, the MBS context area selectively includes a list of local service areas that map to the list of TAs received at the SMF. The MBS context area does not include the full set of local service areas for the multicast session that span the PLMN; the MBS context area selectively includes a subset of the full set. Each local service area is expressed and known at the SMF 202 as a list of Tracking Area Identifiers (TAIs) and cells. The MBS context area includes the intersection of: (a) the TAI received at the SMF 202 in the Nsmf_Request message, and (b) the set of TAI and cells that define the entire set of local service areas for the multicast session. The MBS context area = a list of (Area Session ID, (list of TAI and cells)).

[0206] In the above examples, the SMF 202 receives a list of TAs supported by the gNB 104 and derives from this list of TAs the MBS context area for the gNB 104. According to one example variant, the SMF 202 instead receives a serving gNB identity or a registration area (RA) identity of the UE 100 or a list of cells of the serving gNB; and derives from this alternative information the MBS context area sent to the gNB 104. In another variant, the SMF 202 receives a combination of the above, such as a list of TAs + a list of cells matching the gNB. In one variant, the cell ID of a cell operated by a gNB has a portion (e.g. the leftmost bits) matching the gNB ID; and the SMF 202 can derive the MBS context area from this portion of the gNB ID.

[0207] According to Figure 4 , Figure 6 and Figure 7 another variant of the examples, the AMF 200 provides to the SMF 202 a RA ID of the UE 100 instead of a list of TAs supported by the gNB 104; and the SMF 202 derives the MBS context area to be sent to the gNB 104 based on the one or more TAs making up the identified RA.

[0208] For all the above examples: in response to detecting at the gNB 104 that the UE 100 is served by the gNB 104 (based on the received MBS context area) to belong to a local service area for a multicast session one of its cells, the gNB 104 considers the UE 100 for the multicast session in that cell. In case the UE 100 is the first UE 100 receiving the multicast session via this cell / local service area, the gNB 104 autonomously decides to request the session management function associated with the multicast session (MB-SMF / MB-UPF) to establish a user plane distribution for the multicast session for the cell / local service area.

[0209] The above techniques facilitate the operation of location-dependent multicast sessions having local service areas on a cell granularity, such as for example vehicle-to-everything (V2X) services.

[0210] The above techniques can reduce the signaling between the gNB and the SMF. Whenever a UE hands over to another cell operated by the same gNB, the gNB does not need to request the local service area information to the SMF. The MBS context area received in a single message from the SMF already provides the complete list of the subset of local service areas the gNB participates in, from the larger set of all local service areas for the multicast session

[0211] As mentioned above, the MBS context area provided to the gNB does not include a list of all local service areas for which a multicast session is provided across PLMNs (Public Land Mobile Networks). The above-described techniques are thus particularly suitable for multicast sessions such as, for example, multicast sessions for V2X services, which can have some location-dependent content at one cell (or few cells) level granularity and for which the number of local service areas across PLMNs can be very high (e.g. thousands).

[0212] Figure 8 An example of an apparatus for implementing the operations of a UE 100 or gNB 104 in the above-described embodiments is illustrated. The apparatus can comprise at least one processor 802 coupled to one or more interfaces 808. For the example of a UE 100, the one or more interfaces 808 can be, for example, other devices for which the UE functionality 100 provides radio communication. For the example of a gNB 104, the one or more interfaces 808 can be, for example, a core network node such as a node implementing an AMF 200. The at least one processor 802 is further coupled to a radio 804 comprising one or more antennas or the like for transmitting and receiving radio transmissions. The at least one processor 802 can also be coupled to at least one memory 806. The at least one processor 802 can be configured to execute appropriate software code to perform the above-described operations. The software code can be stored in the memory 806.

[0213] Figure 9 An example of an apparatus for implementing a core network node such as a node implementing an AMF 200 or a node implementing an SMF 202 in the above-described embodiments is illustrated. The apparatus can comprise at least one processor 902 coupled to one or more interfaces 908. The one or more interfaces 908 can be for communicating with a RAN node 104 or other core network nodes. The at least one processor 902 can also be coupled to at least one memory 906. The at least one processor 902 can be configured to execute appropriate software code to perform the above-described operations. The software code can be stored in the memory 906.

[0214] Figure 9 A schematic representation of non-volatile storage media 1100a (e.g. a computer disk (CD) or a digital versatile disk (DVD)) and 1100b (e.g. a universal serial bus (USB) stick) storing instructions and / or parameters 1102 that, when executed by a processor, allow the processor to perform one or more steps of the aforementioned methods is shown.

[0215] It should be noted that embodiments of the present application can be implemented in a circuit, and in software, hardware, application logic or combinations thereof. In example embodiments, application logic, software or an instruction set is maintained on any one of various conventional computer-readable media. In the context of this document, a "computer-readable medium" can be any media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a base station or user equipment of an embodiment of the subject matter.

[0216] As used in this application, the term "circuitry" refers to all of the following: (a) hardware-only circuitry such as only analog and / or digital circuitry, (b) a combination of circuits and software (and / or firmware), such as (as applicable): (i) a combination of processor(s) or (ii) portions of storage medium(s) that include software and / or firmware, that work together to cause an apparatus, such as a user equipment or base station of an embodiment of the subject matter, to perform various functions described herein and (c) circuits, such as a microprocessor(s) or a portion of a microprocessor, that require software or firmware for operation, even if the software or firmware is not physically present. This definition of "circuitry" applies to all uses of this term in this application, including in any claims. As a further example, as used in this application the term "circuitry" would also cover an implementation that includes a processor (or multiple processors) and accompanying software or firmware whose structure is uniquely

[0217] The features, benefits and attributes of the present application described herein can be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the application can be practiced without one or more of the specific features or advantages of a particular embodiment. Additionally, one skilled in the art will recognize or be able to ascertain such features or advantages using no more than routine experimentation. The application described herein will now be demonstrated by the following examples. It will be understood that these examples are illustrative only and are not intended to limit the scope of the application in any way.

Claims

1. An apparatus for a communication network, the apparatus comprising: a session management function configured to perform at least: receiving a list of tracking area identifiers associated with a radio access network node or an identifier of the radio access network node; identifying, based on the list of tracking area identifiers associated with a radio access network node or the identifier of the radio access network node, a subset of multicast service areas of a multicast session managed by the session management function, the subset of multicast service areas comprising a plurality of multicast service areas of a set of multicast service areas of the multicast session; directing information indicating the plurality of multicast service areas towards the radio access network node.

2. The apparatus of claim 1, wherein the radio access network node comprises a target radio access network node for a handover of a user equipment associated with the multicast session.

3. The apparatus of claim 1, wherein the receiving comprises receiving a reply to a request sent by the session management function, the reply comprising the list of tracking area identifiers associated with the radio access network node or the identifier of the radio access network node.

4. The apparatus of claim 1, wherein the session management function is further configured to perform receiving, the receiving comprising receiving the information and a request from a user equipment to join the multicast session.

5. The apparatus of claim 2, wherein the information originates from the target radio access network node.

6. The apparatus of claim 1, wherein the receiving comprises receiving, from an access and mobility management function, a request comprising a message received from the radio access network node, the message comprising the list of tracking area identifiers associated with the radio access network node or the identifier of the radio access network node.

7. The apparatus of claim 1, wherein the plurality of multicast service areas defines a local service area associated with the radio access network node.

8. The apparatus of claim 1, wherein the plurality of multicast service areas defines an area associated with a location of a user equipment associated with the multicast session.

9. The apparatus of claim 1, wherein a respective multicast service area of the plurality of multicast service areas comprises one or more cells of a plurality of cells provided by the radio access network.

10. The apparatus of claim 1, wherein the identifying comprises identifying the plurality of multicast service areas of the set of multicast service areas that are mapped to the tracking area identifiers comprised in the list of tracking area identifiers.

11. An apparatus for a communication network, the apparatus comprising: an access and mobility management function of the communication network, the access and mobility management function configured to perform: receiving, from a radio access network node, a message carrying a join request for a user equipment to join a multicast session and an identifier of the radio access network node; identifying a tracking area associated with the identifier of the radio access network; sending a list of tracking areas to a session management function managing the multicast session, wherein the list of tracking areas comprises a tracking area identifier of the identified tracking area associated with the radio access network; receiving from the session management function information indicating a subset of multicast service areas of the multicast session, the subset comprising a plurality of multicast service areas of a set of multicast service areas of the multicast session identified based on the list of tracking area identifiers; and forwarding the information indicating the plurality of multicast service areas to the radio access network node.

12. The apparatus of claim 11, wherein the plurality of multicast service areas define areas associated with the radio access network node.

13. The apparatus of claim 11, wherein the plurality of multicast service areas define areas associated with a location of a user equipment.

14. The apparatus of claim 11, wherein a respective multicast service area of the plurality of multicast service areas comprises one or more cells of a plurality of cells provided by the radio access network.

15. An apparatus of a radio access network for a communication network, the apparatus comprising: means for sending, to a session management function configured to manage a multicast session associated with a set of multicast service areas or to a access and mobility management function for forwarding to the session management function, a list of tracking area identifiers associated with a radio access network node or an identifier of the radio access network node; means for receiving, from the session management function, information indicating a subset of multicast service areas of the multicast session, the subset being identified based on the list of tracking area identifiers associated with the radio access network node or the identifier of the radio access network node, wherein the subset comprises a plurality of multicast service areas of the set of multicast service areas of the multicast session identified in association with the list of tracking area identifiers.

16. The apparatus of claim 15, wherein the means for sending comprises means for sending the list of tracking area identifiers associated with the radio access network node or the identifier of the radio access network node in a reply to a request from the session management function. means for determining that a radio resource control message received from a user equipment comprises a join request received from the user equipment, wherein the join request indicates that the user equipment is requesting to join the multicast session; and means for including the information and the join request in a message; and means for sending the message to the access and mobility management function.

17. The apparatus of claim 15, comprising:

17. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a tracking area update message.

18. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

19. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

20. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

21. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

22. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

23. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

24. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

25. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

26. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

27. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

28. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

29. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

30. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

31. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

32. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

33. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

34. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

35. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

36. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

37. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

38. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

39. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

40. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

41. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

42. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

43. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

44. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

45. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

46. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

47. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

48. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

49. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

50. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

51. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

52. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

53. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

54. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

55. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

56. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

57. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

58. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

59. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

60. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

61. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

62. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising a service request message.

63. The apparatus of claim 16, wherein the means for determining comprises means for determining that the join request is included in a message comprising 18. The apparatus of claim 15, wherein the means for sending comprises means for sending the list of tracking area identifiers associated with the radio access network node or the identifier of the radio access network node in response to completing handover of a user equipment; and wherein the apparatus further comprises means for sending a path switch request to the session management function via the access and mobility management function, the path switch request comprising the list of tracking area identifiers associated with the radio access network node or the identifier of the radio access network node.

19. The apparatus of claim 15, comprising: means for receiving a radio resource control message from a user equipment, the radio resource control message comprising a join request indicating that the user equipment is requesting to join the multicast session; and wherein the means for sending comprises means for sending a message to the access and mobility management function after receiving the radio resource control message, the message carrying the join request and the identifier of the radio access network node.

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