WO2022033680A1

WO2022033680A1 - Handover of a ue receiving multicast data to an access node not supporting multicasting

Info

Publication number: WO2022033680A1
Application number: PCT/EP2020/072687
Authority: WO
Inventors: David NAVRÁTIL; Philippe Godin; Horst Thomas BELLING
Original assignee: Nokia Technologies Oy
Priority date: 2020-08-12
Filing date: 2020-08-12
Publication date: 2022-02-17

Abstract

There is provided an apparatus comprising means for: determining, at a first access node, that a user equipment receiving data via a multicast session will require handover to a second access node not supporting the multicast session; responsive to the determining, causing a request to be sent from the first access node to a session management function to request provision of transmission data for a multicast session via a unicast session of the user equipment; and transmitting to the second access node a request to hand over the user equipment to the second access node.

Description

HANDOVER OF A UE RECEIVING MULTICAST DATA TO AN ACCESS NODE NOT SUPPORTING MULTICASTING

FIELD

The present application relates to a method, apparatus, system and computer program and in particular but not exclusively to reconfiguring a data session for a user equipment.

BACKGROUND

A communication system can be seen as a facility that enables communication sessions between two or more entities such as user terminals, base stations and/or other nodes by providing carriers between the various entities involved in the communications path. A communication system can be provided for example by means of a communication network and one or more compatible communication devices. The communication sessions may comprise, for example, communication of data for carrying communications such as voice, video, electronic mail (email), text message, multimedia and/or content data and so on. Nonlimiting examples of services provided comprise two-way or multi-way calls, data communication or multimedia services and access to a data network system, such as the Internet.

In a wireless communication system at least a part of a communication session between at least two stations occurs over a wireless link. Examples of wireless systems comprise public land mobile networks (PLMN), satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN). Some wireless systems can be divided into cells, and are therefore often referred to as cellular systems.

A user can access the communication system by means of an appropriate communication device or terminal. A communication device of a user may be referred to as user equipment (UE) or user device. A communication device is provided with an appropriate signal receiving and transmitting apparatus for enabling communications, for example enabling access to a communication network or communications directly with other users. The communication device may access a carrier provided by a station, for example a base station of a cell, and transmit and/or receive communications on the carrier.

The communication system and associated devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. Communication protocols and/or parameters which shall be used for the connection are also typically defined. One example of a communications system is UTRAN (3G radio). Other examples of communication systems are the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology and so-called 5G or New Radio (NR) networks. NR is being standardized by the 3rd Generation Partnership Project (3GPP).

SUMMARY

According to an aspect, there is provided an apparatus comprising means for: determining, at a first access node, that a user equipment receiving data via a multicast session will require handover to a second access node not supporting the multicast session; responsive to the determining, causing a request to be sent from the first access node to a session management function to request provision of transmission data for a multicast session via a unicast session of the user equipment; and transmitting to the second access node a request to hand over the user equipment to the second access node.

The means may be for: receiving, from the session management function, information for reconfiguring the multicast session to the unicast session for the user equipment; and transmitting, to the user equipment, information for reconfiguring the user equipment.

The request to the session management function may be sent prior to the request to the second access node.

The means may be for receiving, from a user plane function, the transmission data in at least one unicast data flow.

The means may be for storing the transmission data in the at least one unicast data flow at the first access node.

The means may be for providing the transmission data in a unicast data flow to the second access node.

The information for reconfiguring the data session may comprise one or more quality of service flows for the transmission data.

The request to the session management function may comprise a downlink tunnel end point information. The determining may be based on configured information at the first access node about the capabilities of the second access node to support multicast sessions and/or based on previous failed attempts to hand over a user equipment receiving data within a multicast session to the second access node.

According to an aspect, there is provided an apparatus comprising means for: receiving, at a session management function from a first access node, a request for provision of transmission data for a multicast session to via a unicast session of a user equipment; and transmitting, to the first access node, information for reconfiguring the session for the user equipment.

The means may be for: transmitting, to at least one user plane function and in response to receiving the request from the first access node, information to instruct the at least one user plane function to provide the transmission data to the first access node in at least one unicast data flow.

The means for transmitting the information to instruct the at least one user plane function may comprise means for: transmitting information to instruct a second session management function to configure a second user plane function to forward the transmission data being provided in a multicast data flow to the at least one user plane function, wherein the second user plane function is configured to provide multicast services, and the at least one user plane function is configured to provide unicast services to the user equipment; and transmitting information to instruct the at least one user plane function to receive the transmission data to be provided to the first access node in the at least one unicast data flow from the second user plane function.

The information for reconfiguring the session may comprise one or more quality of service flows for the transmission data.

The request may comprise a downlink tunnel end point information.

The information transmitted to the at least one user plane function may comprise the downlink tunnel end point information.

According to an aspect, there is provided an apparatus comprising at least one processor and at least one memory including a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to: determine, at a first access node, that a user equipment receiving data via a multicast session will require handover to a second access node not supporting the multicast session; responsive to the determining, cause a request to be sent from the first access node to a session management function to request provision of transmission data for a multicast session via a unicast session of the user equipment; and transmit to the second access node a request to hand over the user equipment to the second access node.

The at least one memory and at least one processor may be configured to cause the apparatus to: receive, from the session management function, information for reconfiguring the multicast session to the unicast session for the user equipment; and transmit, to the user equipment, information for reconfiguring the user equipment.

The at least one memory and at least one processor may be configured to cause the apparatus to: receive, from a user plane function, the transmission data in at least one unicast data flow.

The at least one memory and at least one processor may be configured to cause the apparatus to: store the transmission data in the at least one unicast data flow at the first access node.

The at least one memory and at least one processor may be configured to cause the apparatus to: provide the transmission data in a unicast data flow to the second access node.

The request to the session management function may comprise a downlink tunnel end point information.

The determining may be based on configured information at the first access node about the capabilities of the second access node to support multicast sessions and/or based on previous failed attempts to hand over a user equipment receiving data within a multicast session to the second access node.

According to an aspect, there is provided an apparatus comprising at least one processor and at least one memory including a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to: receive, at a session management function from a first access node, a request for provision of transmission data for a multicast session to via a unicast session of a user equipment; and transmit, to the first access node, information for reconfiguring the session for the user equipment.

The at least one memory and at least one processor may be configured to cause the apparatus to: transmit, to at least one user plane function and in response to receiving the request from the first access node, information to instruct the at least one user plane function to provide the transmission data to the first access node in at least one unicast data flow.

The at least one memory and at least one processor may be configured to cause the apparatus to: transmit information to instruct a second session management function to configure a second user plane function to forward the transmission data being provided in a multicast data flow to the at least one user plane function, wherein the second user plane function is configured to provide multicast services, and the at least one user plane function is configured to provide unicast services to the user equipment; and transmit information to instruct the at least one user plane function to receive the transmission data to be provided to the first access node in the at least one unicast data flow from the second user plane function.

The request may comprise a downlink tunnel end point information.

According to an aspect, there is provided a method comprising: determining, at a first access node, that a user equipment receiving data via a multicast session will require handover to a second access node not supporting the multicast session; responsive to the determining, causing a request to be sent from the first access node to a session management function to request provision of transmission data for a multicast session via a unicast session of the user equipment; and transmitting to the second access node a request to hand over the user equipment to the second access node. The method may comprise: receiving, from the session management function, information for reconfiguring the multicast session to the unicast session for the user equipment; and transmitting, to the user equipment, information for reconfiguring the user equipment.

The method may comprise receiving, from a user plane function, the transmission data in at least one unicast data flow.

The method may comprise storing the transmission data in the at least one unicast data flow at the first access node.

The method may comprise providing the transmission data in a unicast data flow to the second access node.

According to an aspect, there is provided a method comprising: receiving, at a session management function from a first access node, a request for provision of transmission data for a multicast session to via a unicast session of a user equipment; and transmitting, to the first access node, information for reconfiguring the session for the user equipment.

The method may comprise: transmitting, to at least one user plane function and in response to receiving the request from the first access node, information to instruct the at least one user plane function to provide the transmission data to the first access node in at least one unicast data flow. Transmitting the information to instruct the at least one user plane function may comprise: transmitting information to instruct a second session management function to configure a second user plane function to forward the transmission data being provided in a multicast data flow to the at least one user plane function, wherein the second user plane function is configured to provide multicast services, and the at least one user plane function is configured to provide unicast services to the user equipment; and transmitting information to instruct the at least one user plane function to receive the transmission data to be provided to the first access node in the at least one unicast data flow from the second user plane function.

The request may comprise a downlink tunnel end point information.

According to an aspect, there is provided a computer readable medium comprising program instructions for causing an apparatus to perform at least the following: determining, at a first access node, that a user equipment receiving data via a multicast session will require handover to a second access node not supporting the multicast session; responsive to the determining, causing a request to be sent from the first access node to a session management function to request provision of transmission data for a multicast session via a unicast session of the user equipment; and transmitting to the second access node a request to hand over the user equipment to the second access node.

According to an aspect, there is provided a computer readable medium comprising program instructions for causing an apparatus to perform at least the following: receiving, at a session management function from a first access node, a request for provision of transmission data for a multicast session to via a unicast session of a user equipment; and transmitting, to the first access node, information for reconfiguring the session for the user equipment.

According to an aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to any of the preceding aspects. In the above, many different examples have been described. It should be appreciated that further examples may be provided by the combination of any two or more of the examples described above.

DESCRIPTION OF FIGURES

Examples will now be described, by way of example only, with reference to the accompanying Figures in which:

Figure 1 shows a representation of a network system according to some examples;

Figure 2 shows a representation of a control apparatus according to some examples;

Figure 3 shows a representation of an apparatus according to some examples;

Figure 4 shows a representation of a method according to some examples;

Figures 5a and 5b show a method according to some examples;

Figure 6 shows a method according to some examples; and Figure 7 shows a method according to some examples.

DETAILED DESCRIPTION

In the following certain examples are explained with reference to mobile communication devices capable of communication via a wireless cellular system and mobile communication systems serving such mobile communication devices. Before explaining in detail the examples, certain general principles of a wireless communication system, access systems thereof, and mobile communication devices are briefly explained with reference to Figures 1 , 2 and 3 to assist in understanding the technology underlying the described examples.

Figure 1 shows a schematic representation of a 5G system (5GS). The 5GS may be comprised by a terminal or user equipment (UE), a 5G radio access network (5GRAN) or next generation radio access network (NG-RAN), a 5G core network (5GC), one or more application function (AF) and one or more data networks (DN).

The 5G-RAN may comprise one or more gNodeB (GNB) or one or more gNodeB (GNB) distributed unit functions connected to one or more gNodeB (GNB) centralized unit functions. The 5GC may comprise the following entities: Network Slice Selection Function (NSSF); Network Exposure Function; Network Repository Function (NRF); Policy Control Function (PCF); Unified Data Management (UDM); Application Function (AF); Authentication Server Function (AUSF); an Access and Mobility Management Function (AMF); and Session Management Function (SMF). Figure 2 illustrates an example of a control apparatus 200 for controlling a function of the 5GRAN or the 5GC as illustrated on Figure 1. The control apparatus may comprise at least one random access memory (RAM) 211 a, at least on read only memory (ROM) 211b, at least one processor 212, 213 and an input/output interface 214. The at least one processor 212, 213 may be coupled to the RAM 211a and the ROM 211 b. The at least one processor 212, 213 may be configured to execute an appropriate software code 215. The software code 215 may for example allow to perform one or more steps to perform one or more of the present aspects. The software code 215 may be stored in the ROM 211b. The control apparatus 200 may be interconnected with another control apparatus 200 controlling another function of the 5GRAN or the 5GC. In some examples, each function of the 5GRAN or the 5GC comprises a control apparatus 200. In alternative examples, two or more functions of the 5GRAN or the 5GC may share a control apparatus.

Figure 3 illustrates an example of a terminal 300, such as the terminal illustrated on Figure 1. The terminal 300 may be provided by any device capable of sending and receiving radio signals. Non-limiting examples comprise a user equipment, a mobile station (MS) or mobile device such as a mobile phone or what is known as a ’smart phone’, a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle), a personal data assistant (PDA) or a tablet provided with wireless communication capabilities, a machine-type communications (MTC) device, an Internet of things (loT) type communication device or any combinations of these or the like. The terminal 300 may provide, for example, communication of data for carrying communications. The communications may be one or more of voice, electronic mail (email), text message, multimedia, data, machine data and so on.

The terminal 300 may receive signals over an air or radio interface 307 via appropriate apparatus for receiving and may transmit signals via appropriate apparatus for transmitting radio signals. In Figure 3 transceiver apparatus is designated schematically by block 306. The transceiver apparatus 306 may be provided for example by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

The terminal 300 may be provided with at least one processor 301 , at least one memory ROM 302a, at least one RAM 302b and other possible components 303 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communication devices. The at least one processor 301 is coupled to the RAM 311a and the ROM 311b. The at least one processor 301 may be configured to execute an appropriate software code 308. The software code 308 may for example allow to perform one or more of the present aspects. The software code 308 may be stored in the ROM 311b.

The processor, storage and other relevant control apparatus can be provided on an appropriate circuit board and/or in chipsets. This feature is denoted by reference 304. The device may optionally have a user interface such as key pad 305, touch sensitive screen or pad, combinations thereof or the like. Optionally one or more of a display, a speaker and a microphone may be provided depending on the type of the device.

In some examples, an access node of the network may be configured to provide a multicast or broadcast service (MBS) towards UEs.

In the case of a broadcast service, a same service and same specific content data are provided simultaneously to all UEs in a coverage area of the access node. In the case of a multicast service, a same service and same specific content data are provided simultaneously to a dedicated set of UEs, but not all UEs, in the multicast coverage area of the access node.

However, it may be the case that not all access nodes in the communications network are configured to support MBS. Some access nodes that do not support MBS may support unicast services. Thus, when a UE requires handover from a first access node configured to support MBS to a second access node not configured to support MBS (for example, the UE is predicted to move out of the coverage area of the first access node and into the coverage area of the second access node) the delivery method of content to the UE may be switched.

Reference is made to Figure 4, which shows an example representation of such a scenario. In the example of Figure 4, access node 400a is configured to support MBS, whereas access node 400b is not configured to support MBS. The access nodes are connected to application function 404 via core network 406. UE 402, which has previously been receiving a service from application function 404 via MBS from access node 400a, requires handover access node 400b.

Application function 404 may therefore be required to switch to unicast delivery in order for the provided service to continue.

However, the switch from MBS to unicast delivery at application function may be associated with a relatively long latency, which may impact service quality during handover. In some examples, when performing handover, the first access node may send a handover request to the second access node. The handover request may comprise MBS session information and unicast PDU session information. The MBS session information may comprise an associated MBS session identifier.

If the second access node is not configured to support MBS, then after receiving a handover request comprising the MBS session identifier and the unicast PDU session identifier, the second access node may ignore the MBS session identifier, as it is not configured to support MBS. The second access node may therefore proceed with handover using the unicast PDU session identifier.

If the second access node is configured to support MBS, then the second access node may proceed with handover using the MBS session identifier.

In some examples, the UE may receive data via the MBS Session from the first access node. Then, depending on whether the second access node supports MBS or not, the MBS session information may be used to allocate resource.

For example, if the first access node determines that the second access node supports MBS, then the MBS Session information may be used, and a quality of service flow part information corresponding to the MBS session in the unicast PDU session information is not used. However, if the first access node determines that the second access node does not support MBS, then the first access node may initiate an establishment of one or more quality of service flows with the core network and consequently a quality of service flow part information corresponding to the MBS session in the unicast PDU session information is used.

If the second access node supports MBS and the MBS session for the indicated MBS Session has not been established in the second access node, the second access node may allocate shared downlink tunnel information for receiving the MBS data from the core network.

Having received the handover request, the second access node may include the admitted unicast PDU Session information, and, if the MBS Session has been accepted at the second access node, also the MBS Session information, in a response message. Based on the response message, the first access node may determine whether the second access node supports MBS Session or not. However, the unicast PDU session may be configured with one or more quality of service flows for delivering multicast even though the configured quality of service flows may be rarely required as mobility with access nodes not supporting MBS occurs infrequently.

Reference is made to Figures 5a and 5b, which shows an example method.

With reference to Figure 5a, at step 500, the method comprises determining, at a first access node, that a user equipment receiving data via a multicast session will require handover to a second access node not supporting the multicast session.

At step 502, the method comprises, responsive to the determining, causing a request to be sent from the first access node to a session management function to request provision of transmission data for a multicast session via a unicast session of the user equipment.

At step 504, the method comprises transmitting to the second access node a request to hand over the user equipment to the second access node.

With reference to Figure 5b, at step 506, the method comprises receiving, at a session management function from a first access node, a request for provision of transmission data for a multicast session to via a unicast session of a user equipment.

At step 508, the method comprises transmitting, to the first access node, information for reconfiguring the session for the user equipment.

Reference is made to Figure 6, which shows an example method.

In the example of Figure 6, a UE 600 is served by a first access node 602, which is in communication with AMF 606, SMFs 608 and 609, and UPFs 610a and 610b. The network also comprises a second access node 604, which is in communication with the same AMF 606 and SMF 608. It should be understood that, in some other examples, the second access node may be in communication with a different AMF and/or SMF to AMF 606 and SMF 608.

The first access node 602 may support an MBS session, while the second access node 604 may not support an MBS session.

The UE 600 may transmit and receive, via the first access node 602, user data from a first UPF 610a, and multicast data from a second UPF 610b. The AMF 606 may provide mobility control information to the first access node 602. The UE may also provide measurement information and reports to the first access node 602.

At step 612, the first access node may determine that handover to an access node not supporting an MBS session is to be performed.

The first access node 602 may obtain information about the support of MBS sessions in neighbouring access nodes. For example, the first access node 602 may be preconfigured with the information about neighbouring access nodes. The first access node 602 may determine that handover to an access node not supporting an MBS session is required based on the information.

Additionally or alternatively, the first access node 602 may determine whether neighbouring access nodes support MBS sessions based on previous handover attempts to the neighbouring access nodes. For example, the first access node 602 may determine a number of failed handovers of multicast flows, or may receive notifications about not comprehended information elements relating to multicast session information, thereby indicating that a neighbouring access node does not support MBS. The multicast session information may comprise at least one of an MBS session identifier, a quality of service flow identifier, and quality of service flow parameters.

At step 614, responsive to the determining at 612, the first access node may provide, to the SMF 608, an indication that the MBS session is to be switched to a unicast PDU session. The indication may comprise a downlink (DL) tunnel information. . The downlink tunnel information may indicate an address of the access node to which data is to be sent by a UPF, and a downlink (DL) tunnel end point identifier (TEID) to use in headers of packets carrying data.

At step 616, responsive to receiving the indication at 614, the SMF may generate a configuration for the first UPF 610a. The SMF may send the configuration to the first UPF 610a. The configuration may comprise DL TEID and a quality of service flow for transmission of multicast data to the first access node 602. The first UPF 610a may transmit, to the SMF, information indicating an address at the first UPF 610a where data from the second UPF 610b should be sent.

At step 618, responsive to receiving the indication at 614, the SMF 608, may generate a request for a second SMF controlling the second UPF to send multicast data to the address at the first UPF. At step 619, the second SMF may provide a configuration for the second UPF 610b. The second SMF may send the configuration to the second UPF 610b. The second SMF may also send information indicating the address at the first UPF 610a where the second UPF 610b is to send data. Responsive to receiving the configuration the second UPF 610b may forward multicast data to the first UPF 610a. The data may be forwarded based on the information indicating the address at the first UPF 610a.

At step 620, the SMF 608 may generate configurations for the first access node 604 and the UE. The configurations may comprise an update of PDU session with one or more quality of service flows for the multicast data. The SMF may send, in a response to receiving the indication that the MBS session is to be switched to a unicast PDU session, a modification request message to the first access node. The modification request message may comprise the generated configurations. The response may be a session modification request.

At step 622, responsive to receiving the configurations at 620, the first access node 604 may forward the UE configuration received from the SMF to the UE 600. The first access node 602 may provide, to UE 600, an RRC reconfiguration message comprising the received UE configuration. The RRC reconfiguration message may comprise a PDU session modification command.

At step 624, responsive to receiving the configuration from the SMF at 618, the first UPF 610a may provide, to the first access node, the multicast data received from the second UPF 610b in one or more unicast quality of service flows. The first UPF 610a may also provide other user data to the first access node.

At step 626, the first access node 604 may store the multicast data and user data received at 624 in a buffer. The data may be stored until the UE 600 confirms the reconfiguration by transmitting an RRC Reconfiguration Complete message to the first access node 602.

Once the first access node 602 receives the RRC Reconfiguration Complete message at step 628, at step 630, the first access node may confirm successful PDU session modification to the SMF 606. The first access node may send a session modification response to the SMF indicating successful session modification.

A handover process may then be performed. An example handover process is further described with further reference to Figure 7. The process shown in Figure 7 may continue on from the process shown in Figure 6. Common elements between Figures 6 and 7 are given the same reference numerals.

At step 700 the first access node 602 may determine that UE 600 is to be handed over to the second access node 604.

At step 702, responsive to the determining at 700, the first access node 602 may send a handover request to the second access node 604. The handover request may comprise one or more quality of service flows for unicast PDU session information. In some examples, when the first access node determines that the second access node is unlikely to support MBS, MBS information may be excluded from the handover request message sent to the second access node.

At step 704, in response to the request sent by the first access node at 702, the second access node may acknowledge the handover request to the first access node 602.

At step 706, having received the response at 704, the first access node 602 may initiate handover with UE 600, causing UE 600 to detach from the first access node 602 and attach to the second access node 604.

At step 708, while handover is taking place, the first access node 602 may forward the multicast data and user data stored in the buffer at 626 to the second access node 604. Additional data received from the UPFs 610a and 610b may be additionally or alternatively forwarded by the first access node 602 to the second access node 604.

Upon completion of handover, at step 710, the second access node 604 may forward the data received from the first access node 602 to UE 600 based on the quality of service flow for unicast PDU session information.

Thus, in some examples, the UPFs and access nodes may be reconfigured to deliver multicast data in one or more quality of service flows for unicast PDU session. The reconfiguration may be performed before the access node actually requests handover. As such, some examples may reduce latency issues affecting the quality of service associated with other methods when a UE is handed over from an access node supporting an MBS session to an access node that does not support an MBS session. In some examples, there is provided an apparatus comprising means for: determining, at a first access node, that a user equipment receiving data via a multicast session will require handover to a second access node not supporting the multicast session; responsive to the determining, causing a request to be sent from the first access node to a session management function to request provision of transmission data for a multicast session via a unicast session of the user equipment; and transmitting to the second access node a request to hand over the user equipment to the second access node.

In some examples, there is provided an apparatus comprising means for: receiving, at a session management function from a first access node, a request for provision of transmission data for a multicast session to via a unicast session of a user equipment; and transmitting, to the first access node, information for reconfiguring the session for the user equipment.

In some examples, there is provided an apparatus comprising at least one processor and at least one memory including a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to: determine, at a first access node, that a user equipment receiving data via a multicast session will require handover to a second access node not supporting the multicast session; responsive to the determining, cause a request to be sent from the first access node to a session management function to request provision of transmission data for a multicast session via a unicast session of the user equipment; and transmit to the second access node a request to hand over the user equipment to the second access node.

In some examples, there is provided an apparatus comprising at least one processor and at least one memory including a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to: receive, at a session management function from a first access node, a request for provision of transmission data for a multicast session to via a unicast session of a user equipment; and transmit, to the first access node, information for reconfiguring the session for the user equipment.

It should be understood that the apparatuses may comprise or be coupled to other units or modules etc., such as radio parts or radio heads, used in or for transmission and/or reception. Although the apparatuses have been described as one entity, different modules and memory may be implemented in one or more physical or logical entities. It is noted that whilst some examples have been described in relation to 5G networks, similar principles can be applied in relation to other networks and communication systems. Therefore, although certain examples were described above by way of example with reference to certain example architectures for wireless networks, technologies and standards, examples may be applied to any other suitable forms of communication systems than those illustrated and described herein.

It is also noted herein that while the above describes examples, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention.

In general, the various examples may be implemented in hardware or special purpose circuitry, software, logic or any combination thereof. Some aspects of the disclosure may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the disclosure is not limited thereto. While various aspects of the disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable):

(i) a combination of analog and/or digital hardware circuit(s) with software/firmware and

(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.”

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 also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

The examples of this disclosure may be implemented by computer software executable by a data processor of the mobile device, such as in the processor entity, or by hardware, or by a combination of software and hardware. Computer software or program, also called program product, including software routines, applets and/or macros, may be stored in any apparatus- readable data storage medium and they comprise program instructions to perform particular tasks. A computer program product may comprise one or more computer-executable components which, when the program is run, are configured to carry out examples. The one or more computer-executable components may be at least one software code or portions of it.

Further in this regard it should be noted that any blocks of the logic flow as in the Figures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD. The physical media is a non-transitory media.

The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may comprise one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), FPGA, gate level circuits and processors based on multi core processor architecture, as non-limiting examples.

Examples in the disclosure may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate. The scope of protection sought for various examples of the disclosure is set out by the independent claims. The examples and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various examples of the disclosure.

The foregoing description has provided by way of non-limiting examples a full and informative description of the examples of this disclosure. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this disclosure will still fall within the scope of this invention as defined in the appended claims. Indeed, there is a further example comprising a combination of one or more examples with any of the other examples previously discussed.

Claims

1 . An apparatus comprising means for: determining, at a first access node, that a user equipment receiving data via a multicast session will require handover to a second access node not supporting the multicast session; responsive to the determining, causing a request to be sent from the first access node to a session management function to request provision of transmission data for a multicast session via a unicast session of the user equipment; and transmitting to the second access node a request to hand over the user equipment to the second access node.

2. The apparatus of claim 1 , further comprising means for: receiving, from the session management function, information for reconfiguring the multicast session to the unicast session for the user equipment; and. transmitting, to the user equipment, information for reconfiguring the user equipment.

3. The apparatus of any of claims 1 and 2, wherein the request to the session management function is sent prior to the request to the second access node.

4 The apparatus of any preceding claim, wherein the means is for receiving, from a user plane function, the transmission data in at least one unicast data flow.

5. The apparatus of claim 4, wherein the means is for storing the transmission data in the at least one unicast data flow at the first access node.

6. The apparatus of any of claims 4 to 5, wherein the means is for providing the transmission data in a unicast data flow to the second access node.

7. The apparatus of any of claims 2 to 6, wherein the information for reconfiguring the data session comprises one or more quality of service flows for the transmission data.

8. The apparatus of any preceding claim, wherein the request to the session management function comprises a downlink tunnel end point information.

9. The apparatus of any preceding claim, wherein the determining is based on configured information at the first access node about the capabilities of the second access node to support multicast sessions and/or based on previous failed attempts to hand over a user equipment receiving data within a multicast session to the second access node.

10. An apparatus comprising means for: receiving, at a session management function from a first access node, a request for provision of transmission data for a multicast session to via a unicast session of a user equipment; and transmitting, to the first access node, information for reconfiguring the session for the user equipment.

11. The apparatus of claim 10, comprising means for transmitting, to at least one user plane function and in response to receiving the request from the first access node, information to instruct the at least one user plane function to provide the transmission data to the first access node in at least one unicast data flow.

12. The apparatus of claim 11 , wherein the means for transmitting the information to instruct the at least one user plane function comprises means for: transmitting information to instruct a second session management function to configure a second user plane function to forward the transmission data being provided in a multicast data flow to the at least one user plane function, wherein the second user plane function is configured to provide multicast services, and the at least one user plane function is configured to provide unicast services to the user equipment; and transmitting information to instruct the at least one user plane function to receive the transmission data to be provided to the first access node in the at least one unicast data flow from the second user plane function.

13. The apparatus of any of claims 10 to 12, wherein the information for reconfiguring the session comprises one or more quality of service flows for the transmission data.

14. The apparatus of any of claims 10 to 13, wherein the request comprises a downlink tunnel end point information.

15. The apparatus of claim 14, wherein the information transmitted to the at least one user plane function comprises the downlink tunnel end point information.

16. An apparatus comprising at least one processor and at least one memory including a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to: determine, at a first access node, that a user equipment receiving data via a multicast session will require handover to a second access node not supporting the multicast session; responsive to the determining, cause a request to be sent from the first access node to a session management function to request provision of transmission data for a multicast session via a unicast session of the user equipment; and transmit to the second access node a request to hand over the user equipment to the second access node.

17. An apparatus comprising at least one processor and at least one memory including a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to: receive, at a session management function from a first access node, a request for provision of transmission data for a multicast session to via a unicast session of a user equipment; and transmit, to the first access node, information for reconfiguring the session for the user equipment.

18. A method comprising: determining, at a first access node, that a user equipment receiving data via a multicast session will require handover to a second access node not supporting the multicast session; responsive to the determining, causing a request to be sent from the first access node to a session management function to request provision of transmission data for a multicast session via a unicast session of the user equipment; and transmitting to the second access node a request to hand over the user equipment to the second access node.

19. A method comprising: receiving, at a session management function from a first access node, a request for provision of transmission data for a multicast session to via a unicast session of a user equipment; and transmitting, to the first access node, information for reconfiguring the session for the user equipment.