WO2018130290A1

WO2018130290A1 - Radio resource management in a group communications system

Info

Publication number: WO2018130290A1
Application number: PCT/EP2017/050614
Authority: WO
Inventors: Magnus TRÄNK; Mikael Persson
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2017-01-12
Filing date: 2017-01-12
Publication date: 2018-07-19

Abstract

There is provided mechanisms for radio resource management in a group communications system. A method is performed by a packet data network gateway (PGW). The method comprises receiving a gating control request from a Policy and Charging Rules Function (PCRF) for disabling a unicast service data flow of an ongoing group communications session of the group communications system. The method comprises sending, in response to having received the gating control request, an update bearer request towards a radio access network node for releasing unicast radio resources of the ongoing group communications session.

Description

RADIO RESOURCE MANAGEMENT IN A GROUP COMMUNICATIONS SYSTEM

TECHNICAL FIELD

Embodiments presented herein relate to methods, a packet data network gateway, a control node, computer programs, and a computer program product for radio resource management in a group communications system.

BACKGROUND

In communications networks, there may be a challenge to obtain good performance and capacity for a given communications protocol, its parameters and the physical environment in which the communications network is deployed.

An example of applications available in some communications system is group communications services. In general terms, group communications means that the same information or media is delivered to multiple client nodes. In group communications systems (e.g., Push-To-Talk (PTT) systems) the client nodes receiving the same media constitute a group of client nodes. These client nodes may be located at different locations. Herein, multicast transmission, or simply multicast, is an example of group communications. Multicast communications, or multicast, may be seen as communications (e.g. transmission) from a single sender to multiple receivers. If client nodes are spread out over a large geographical area it can be more efficient to use unicast transmission for communications to the group of client nodes.

Unicast transmission, or simply unicast, may be seen as communications (e.g. transmission) from a single sender to a single receiver. Further, typically the area served by multicast is commonly smaller than the area served by unicast within the full area served by the group communications service. Hence some client nodes will receive the group communications over unicast and some over multicast. Client nodes that are moving around in the area served by the group communications service may thus need to dynamically switch from multicast to unicast, or vice versa, depending on the extension of the area served by multicast in the area served by the group communications service.

Multicast radio resources are typically allocated before the group

communications service is started, due to the performance requirements on group call establishments. Allocation of unicast radio resource may be performed at establishment of the group communications service or when the unicast radio resources are required (e.g. when a client node is transmitting, when the allocated multicast radio resources are already in use by other group communications sessions, or when a client node is leaving the area served by multicast).

A client node may be provided in, or installed on, a wireless device. When a wireless device uses unicast transmission in a long Term Evolution (LTE) network it connects to an Evolved Packet System (EPS) network according to 3GPP TS 23.002 V14.0.0. The wireless device uses a virtual connection called an EPS Bearer, which enables transport of the traffic flow, i.e. Service Data Flows (SDF) according to 3GPP TS 23.203 V14.1.0. The EPS Bearer is defined in 3GPP TS 23.401 V14.1.0 and 3GPP TS 36.300 V14.0.0. Fig. 1 illustrates the bearer architecture for the EPS for an end-to-end service between a wireless device 150a and a peer entity 300 (such as a group communications control node). An E-RAB (E-UTRAN Radio Access Bearer, where E-UTRAN is short for Evolved Universal Terrestrial Radio Access Network) transports the packets of an EPS bearer between the wireless device and the evolved Packet Core (EPC) network. When an E-RAB exists, there is a one-to-one mapping between this E-RAB and an EPS bearer. A data radio bearer transports the packets of an EPS bearer between the wireless device and an evolved NodeB (eNB) 110. When a data radio bearer exists, there is a one-to-one mapping between this data radio bearer and the EPS bearer/E-RAB. An Si bearer transports the packets of an E-RAB between an eNB and a Serving Gateway (SGW) 190. An S5/S8 bearer transports the packets of an EPS bearer between a SGW and a packet data network gateway (PGW) 200. A wireless device stores a mapping between an uplink packet filter and a data radio bearer to create the binding between an SDF and a data radio bearer in the uplink. The PGW stores a mapping between a downlink packet filter and an Ss/S8a bearer to create the binding between an SDF and an Ss/S8a bearer in the downlink. The eNB stores a one-to-one mapping between a data radio bearer and an Si bearer to create the binding between a data radio bearer and an Si bearer in both the uplink and downlink. The SGW stores a one-to-one mapping between an Si bearer and an Ss/S8a bearer to create the binding between an Si bearer and an Ss/S8a bearer in both the uplink and downlink.

An EPS bearer is configured to be either a GBR (Guaranteed Bit Rate) or a non-GBR bearer. In a group communications system a GBR bearer is typically used due to the requirements for real time communication. When using a GBR bearer the radio resources are reserved for the SDF.

When transferring the transmission from unicast to multicast (e.g. during an ongoing group communication service) it is desirable to efficiently, e.g. with a minimize packet loss and/or a minimum of radio resource allocation, be able to return to a unicast transmission. One example if this may be when the multicast radio resources are lost. Indeed, if the EPS unicast bearer remains established during multicast transmissions this may facilitate a return to unicast, but this could result in a waste of radio resources.

Hence, there is still a need for improved radio resource allocation

mechanisms in a group communications system.

SUMMARY

An object of embodiments herein is to provide efficient radio resource management in a group communications system.

According to a first aspect there is presented a method for radio resource management in a group communications system. The method is performed by a packet data network gateway (PGW). The method comprises receiving a gating control request from a Policy and Charging Rules Function (PCRF) for disabling a unicast service data flow of an ongoing group communications session of the group communications system. The method comprises sending, in response to having received the gating control request, an update bearer request towards a radio access network node for releasing unicast radio resources of the ongoing group communications session.

According to a second aspect there is presented a PGW in a group

communications system. The PGW comprises processing circuitry. The processing circuitry is configured to cause the PGW to receive a gating control request from a PCRF for disabling a unicast service data flow of an ongoing group communications session of the group communications system. The processing circuitry is configured to send, in response to having received the gating control request, an update bearer request towards a radio access network node for releasing unicast radio resources of the ongoing group communications session.

According to a third aspect there is presented a PGW in a group

communications system. The PGW comprises processing circuitry, and a storage medium. The storage medium stores instructions that, when executed by the processing circuitry, cause the PGW to perform operations, or steps. The operations, or steps, cause the PGW to receive a gating control request from a PCRF for disabling a unicast service data flow of an ongoing group communications session of the group communications system. The operations, or steps, cause the PGW to send, in response to having received the gating control request, an update bearer request towards a radio access network node for releasing unicast radio resources of the ongoing group communications session.

According to a fourth aspect there is presented a PGW in a group

communications system. The PGW comprises a receive module configured to receive a gating control request from a PCRF for disabling a unicast service data flow of an ongoing group communications session of the group communications system. The PGW comprises a send module configured to send, in response to the PGW having received the gating control request, an update bearer request towards a radio access network node for releasing unicast radio resources of the ongoing group communications session. According to a fifth aspect there is presented a computer program for radio resource management in a group communications system, the computer program comprising computer program code which, when run on processing circuitry of a PGW, causes the PGW to perform a method according to the first aspect.

According to a sixth aspect there is presented a method for radio resource management in a group communications system. The method is performed by a control node of the group communications system. The method comprises requesting, by sending a request to a PCRF to disable a unicast service data flow of an ongoing group communications session of the group communications system, a radio access network node to release unicast radio resources of the ongoing group communications session.

According to a seventh aspect there is presented a control node for radio resource management in a group communications system. The control node comprises processing circuitry. The processing circuitry is configured to cause the control node to request, by sending a request to a PCRF to disable a unicast service data flow of an ongoing group communications session of the group communications system, a radio access network node to release unicast radio resources of the ongoing group communications session. According to an eighth aspect there is presented a control node for radio resource management in a group communications system. The control node comprises processing circuitry, and a storage medium. The storage medium stores instructions that, when executed by the processing circuitry, cause the control node to request, by sending a request to a PCRF to disable a unicast service data flow of an ongoing group communications session of the group communications system, a radio access network node to release unicast radio resources of the ongoing group communications session.

According to a ninth aspect there is presented a control node for radio resource management in a group communications system. The control node comprises a request module configured to request, by sending a request to a PCRF to disable a unicast service data flow of an ongoing group

communications session of the group communications system, a radio access network node to release unicast radio resources of the ongoing group communications session. According to a tenth aspect there is presented a computer program for radio resource management in a group communications system, the computer program comprising computer program code which, when run on processing circuitry of a control node, causes the control node to perform a method according to the sixth aspect. According to an eleventh aspect there is presented a computer program product comprising a computer program according to at least one of the fifth aspect and the tenth aspect and a computer readable storage medium on which the computer program is stored. The computer readable storage medium could be a non-transitory computer readable storage medium. Advantageously these methods, these PGWs, these control nodes, and these computer programs provide efficient radio resource management in the group communications system.

Advantageously these methods, these PGWs, these control nodes, and these computer programs enable efficient transfer of a transmission from multicast to unicast (e.g. during an ongoing group communications session).

Advantageously these methods, these PGWs, these control nodes, and these computer programs provide efficient control of radio resources utilized by the group communications system, whilst still enable requirements to transfer ongoing group communications from multicast to unicast to be reached. It is to be noted that any feature of the first, second, third, fourth, fifth, sixth seventh, eight, ninth, tenth and eleventh aspects may be applied to any other aspect, wherever appropriate. Likewise, any advantage of the first aspect may equally apply to the second, third, fourth, fifth, sixth, seventh, eight, ninth, tenth, and/or eleventh aspect, respectively, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following detailed disclosure, from the attached dependent claims as well as from the drawings.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive concept is now described, by way of example, with reference to the accompanying drawings, in which:

Fig. l is a schematic illustration of a bearer architecture according to embodiments;

Fig. 2 is a schematic diagram illustrating a communications system according to embodiments;

Figs. 3, 4, 5, and 6 are flowcharts of methods according to embodiments;

Figs. 7 and 8 are signalling diagrams according to embodiments; Fig. 9 is a schematic diagram showing functional units of a PGW according to an embodiment;

Fig. 10 is a schematic diagram showing functional modules of a PGW according to an embodiment;

Fig. 11 is a schematic diagram showing functional units of a control node according to an embodiment;

Fig. 12 is a schematic diagram showing functional modules of a control node according to an embodiment; and Fig. 13 shows one example of a computer program product comprising computer readable means according to an embodiment.

DETAILED DESCRIPTION

The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the inventive concept are shown. This inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout the description. Any step or feature illustrated by dashed lines should be regarded as optional.

Fig. 2 is a schematic diagram illustrating a communications system 100 where embodiments presented herein can be applied. The communications system 100 is assumed to provide services for group communications and may hence be regarded as a group communications system. The group communications system 100 is, according to some aspects, a push to talk (PTT) system. The group communications system provides group

communication services to client nodes 160a, 160b, 160c. The communications system 100 comprises a radio access network 120, a core network 130, and a service network 140. The communications system 100 further comprises at least one control node 300 and at least one client node 160a, 160b, 160c. The at least one control node 300 may be provided in, or installed on, a radio access network node 110 or in another entity or device in the radio access network 120, in an entity or device of the core network 130, or in an entity or device of the service network 140. The at least one control node 300 could implement the functionality of a group

communications application server (GCS AS). Each client node 160a, 160b, 160c may be provided in, or installed on, a respective wireless device 150a, 150b, 150c. The nodes indicated herein may be seen as functions, where each function may be implemented in one or more physical entities. The radio access network 120 is operatively connected to the core network 130 which in turn is operatively connected to the service network 140. The radio access network node 110 thereby enables the wireless devices 150a, 150b, 150c, and hence the client nodes 160a, 160b, 160c, to access services and exchange data as provided by the service network 140.

With relevance to the embodiments disclosed herein the core network 130 comprises a Mobility Management Entity (MME) 170, a Policy and Charging Rules Function (PCRF) 180, a Serving Gateway (SGW) 190, and a packet data network gateway (PGW) 200. The MME 170 is responsible for tracking and paging procedure, and also for idle mode of the wireless devices 150a, 150b, 150c. The MME 170 is also involved in bearer activation and its deactivation procedures, to its task also belongs choosing the SGW 190 for a wireless device 150a, 150b, 150c in process of initial attach and when the intra-handover take place which involves core network node relocation.

The PCRF 180 encompasses policy control decision and flow-based charging control functionalities for the wireless devices 150a, 150b, 150c.

The SGW 190 is the gateway which terminates the interface towards the radio access network 120. For each wireless device 150a, 150b, 150c associated with the EPS, at given point of time, there is a single SGW 190. The SGW 190 is responsible for handovers with neighbouring radio access network nodes 110, also for data transfer in terms of all packets across user plane. The SGW 190 is monitoring and maintaining context information related to the wireless device 150a, 150b, 150c during connected and idle state. The PGW 200 is the gateway which terminates interface SGi towards the packet data network (PDN) as herein defined by the service network 140. If a wireless device 150a, 150b, 150c is accessing multiple PDNs, there may be more than one PGW 200 for that wireless device 150a, 150b, 150c. Further functionality of the PGW 200 as proposed by the herein disclosed

embodiments will be disclosed below. As the skilled person understands the core network 130 may comprises further functions, entities, and/or devices, as in state of the art.

Examples of wireless devices 150a, 150b, 150c include, but are not limited to, mobile stations, mobile phones, handsets, wireless local loop phones, user equipment (UE), smartphones, laptop computers, and tablet computers. Examples of radio access network nodes 110 include, but are not limited to, radio base stations, base transceiver stations, node Bs, evolved node Bs, and access points. As the skilled person understands, the communications system 100 may comprise a plurality of radio access network nodes 110, each providing network access to a plurality of wireless devices 150a, 150b, 150c. The herein disclosed embodiments are not limited to any particular number of radio access network nodes 110, client nodes 160a, 160b, 160c, or wireless devices 150a, 150b, 150c.

As disclosed above, client nodes 160a, 160b, 160c that are moving around in the area served by the group communications service may need to

dynamically switch from multicast to unicast, or vice versa. On the one hand, when using multicast bearers for group communication, the reserved unicast radio resources should be released for the receiving client nodes 160a, 160b, 160c for radio resource efficiency reasons. On the other hand, to quickly provide access to unicast radio resources, the EPS bearer context must be preserved in the EPS system since otherwise there is a risk for packet loss when multicast radio resources becomes unavailable and a transfer to unicast transmission is required.

In current EPS networks the EPS bearer context is not preserved when EPS bearer is terminated and/or released, unless the wireless device 150a, 150b, 150c enters an idle state, i.e. an operating state where the radio transmitter is disabled. The ability to cause a wireless device 150a, 150b, 150c to enter idle state is out of control of the group communications system and particularly out of control of the control node 300. The embodiments disclosed herein therefore relate to mechanisms for radio resource management in a group communications system 100. In order to obtain such mechanisms there is provided a PGW 200, a method performed by the PGW 200, a computer program product comprising code, for example in the form of a computer program, that when run on processing circuitry of the PGW 200, causes the PGW 200 to perform the method. In order to obtain such mechanisms there is further provided a control node 300, a method performed by the control node 300, and a computer program product comprising code, for example in the form of a computer program, that when run on processing circuitry of the control node 300, causes the control node 300 to perform the method.

Figs. 3 and 4 are flow charts illustrating embodiments of methods for radio resource management in a group communications system 100 as performed by the PGW 200. Figs. 5 and 6 are flow charts illustrating embodiments of methods for radio resource management in a group communications system 100 as performed by the control node 300. The methods are advantageously provided as computer programs 1320a, 1320b.

Reference is now made to Fig. 3 illustrating a method for radio resource management in a group communications system 100 as performed by the PGW 200 according to an embodiment.

S102: The PGW 200 receives a gating control request from a PCRF 180 for disabling a unicast service data flow of an ongoing group communications session of the group communications system 100.

The unicast service data flow of the ongoing group communications session could be disabled for at least one of the client nodes 160a, 160b, 160c.

An example of a gating functionality is provided in the Policy and Charging Control (PCC) architecture (for example as disclosed in 3GPP TS 23.203

V14.1.0) of an EPS network. The gating functionality provides a mechanism to block the traffic by dropping the service data flow packets in a packet gateway such as the PGW 200. According to the herein disclosed embodiments the gating functionality is extended to also request a release of radio resources in the radio access network node no (and thus in the wireless devices 150a, 150b, 150c), and by that release the radio resources related to a specific service data flow that are subject for gating. Hence, the PGW 200 is configured to perform step S106:

S106: The PGW 200 sends, in response to having received the gating control request, an update bearer request towards a radio access network node 110 for releasing unicast radio resources of the ongoing group communications session. Sending an update bearer request towards the radio access network node 110 should be understood such that at least parts of the information in the update bearer request is intended for the radio access network node 110, and that the information may traverse other nodes (e.g. such as the MME 170) before it is received by the radio access network node 110. A unicast radio resource may relate to, or be associated with, a unicast bearer, e.g. such as a unicast radio bearer or a unicast E-RAB or a unicast S5/S8 bearer (c.f. Fig. 1), that is associated with a specific service data flow that is subject for gating in step Si02.In general terms, the gating control request relates to a gating policy that is to be applied on the PGW 200 on a per service data flow basis. The gating policy is provisioned to the PGW 200 within a PCC rule. The Flow-Status Attribute-Value Pairs (AVP) of the PCC rule describes whether the uplink and downlink gate is opened or closed. The commands to open or close the gate leads to the enabling or disabling of the passage of IP packets corresponding to the PCC rule. If the gate is closed all packets of the related IP flows are dropped by the PGW 200. If the gate is opened the packets of the related service data flows are allowed to be forwarded. This means that when gating is enabled in the PGW 200, packets are dropped regardless of the radio access controlled by the radio access network node 110. Even though the gating is enabled in the PGW 200, the radio access network node 110 still reserves radio resources for the radio bearer associated to the service data flow currently under gating control. The gating control request received by the PGW 200 in step S102 could therefore be considered to define a modified PCC rule in which one or more service data flows are disabled. The PGW 200 then in step S106 sends an update bearer request, for exampling informing the radio access network node 110 of an updated bitrate of the unicast radio resources that causes the radio access network node 110 to release unicast radio resources of the ongoing group communications session.

Steps S102 and S106 thus define a method to release unicast radio resources whilst still preserving the unicast bearer context in the communications network, e.g. in the PGW 200. The unicast bearer context may be associated with a unicast bearer, e.g. such as a unicast radio bearer or a unicast E-RAB or a unicast S5/S8 bearer (c.f. Fig. 1). The preservation of the unicast bearer context enables a quick transfer of the group communications session from multicast to unicast transmission in scenarios where multicast radio resources are not available. According to some aspects a unicast bearer context associated with the unicast service data flow is thus preserved when the unicast service data flow is disabled.

Embodiments relating to further details of radio resource management in a group communications system 100 as performed by the PGW 200 will now be disclosed.

Reference is now made to Fig. 4 illustrating methods for radio resource management in a group communications system 100 as performed by the PGW 200 according to further embodiments. It is assumed that steps S102, S106 are performed as described above with reference to Fig. 3 and a thus repeated description thereof is therefore omitted.

As noted above, the gating policy is applied by the PGW 200 on a per service data flow basis. Hence, according to an embodiment the gating control request is received per service data flow of the ongoing group

communications session. The update bearer request sent to the radio access network node 110 could request the radio access network node 110 to release radio resources. Hence, according to an embodiment the update bearer request pertains to at least temporarily releasing the unicast radio resources allocated to the service data flow.

According to an embodiment the unicast service data flow is transported using an EPS bearer. The PGW 200 could then adjusts the bitrate of the EPS bearer by reducing the bitrate that is associated to the service data flow(s) currently under gating control. Hence, according to an embodiment the PGW 200 is configured to perform step S104:

S104: The PGW 200 adjusts bitrate of the EPS bearer by reducing bitrate of the unicast service data flow.

As an alternative to step S104, the PCRF 180 may take the decision to adjust the bitrate due to gating request from the control node 300 (implementing the functionality of an Application Function (AF)). In such a case the PCRF 180 sets a new bitrate in the PCC rule. Hence, according to an embodiment the gating control request indicates an adjusted bitrate of the EPS bearer by the gating control request having a reduced bitrate of the unicast service data flow. Gating may be enforced to less than all service data flows on the EPS bearer. The deducted bitrate is then the sum of the bitrates for those affected service data flows subject for gating. Hence, according to an embodiment the update bearer request pertains to less than all service data flows of the EPS bearer.

Alternatively, all service data flows of the EPS bearer are under gating control and the EPS system preserves EPS connectivity but releases all network radio resources. Hence, according to an embodiment the update bearer request pertains to all service data flows of the EPS bearer, and the update bearer request pertains to preserving network connectivity of the EPS bearer whilst releasing all radio resources allocated for the EPS bearer. Reference is now made to Fig. 5 illustrating a method for radio resource management in a group communications system 100 as performed by the control node 300 according to an embodiment.

S202: The control node 300 requests to release unicast radio resources of the ongoing group communications session. The request is carried out by the control node 300 sending a request to a PCRF 180 to disable a unicast service data flow of the ongoing group communications session of the group communications system 100.

The PCRF 180, upon reception of the request from the control node 300, then sends the gating control request that is received by the PGW 200 in above step S102.

Embodiments relating to further details of radio resource management in a group communications system 100 as performed by the control node 300 will now be disclosed. There could be different factors according to which the control node 300 determines that the unicast radio resources of the ongoing group

communications session should be released, and hence that trigger the control node 300 to perform step S202.

According to some aspects the control node 300 determines to at least temporarily disable the unicast transmission when a client node 160a, 160b, 160c just enters an area served by multicast transmission and can start to receive the group communications session over an Multicast-Broadcast Multimedia Services (MBMS) bearer.

According to some aspects the control node 300 determines to at least temporarily disable the unicast transmission when a group communications session is just transferred to MBMS transmission due to that the MBMS bearer was just started or that MBMS bearer capacity became available.

Reference is now made to Fig. 6 illustrating methods for radio resource management in a group communications system 100 as performed by the control node 300 according to further embodiments. It is assumed that step S202 is performed as described above with reference to Fig. 5 and a thus repeated description thereof is therefore omitted.

According to some aspects the control node 300 informs the client node 160a, 160b, 160c that dedicated radio resources have been released. Hence, according to an embodiment the control node 300 is configured to perform step S204:

S204: The control node 300 informs at least one client node 160a, 160b, 160c in the group communications system 100 that the unicast radio resources of the ongoing group communications session have been released.

A first particular embodiment for radio resource management in a group communications system 100 based on at least some of the above disclosed embodiments will now be disclosed in detail with reference to the signalling diagram of Fig. 7. S301: A group communications session is active and the group

communications system 100 is using multicast transmission to transmit group communications data towards the client nodes 160a, 160b, 160c.

S302: The control node 300 determines to at least temporarily disable the unicast transmission (i.e. disable the service data flow), without removing the EPS unicast connectivity, and by that also release the radio resources that has been allocated for the group communications session. Step S302 causes the service data flow to be disabled by the control node 300 which implements the Application Function (AF) by sending a request to the PCRF 180 over interface Rx as defined in 3GPP TS 29.214 V14.1.0. The control node 300 may thus be enabled to request/update/remove network radio resources (i.e. unicast radio resources) over the Rx interface. Details of step S302 are illustrated as step S401 in Fig. 8. One way to implement step S302 is to perform step S202. S303: The PCRF 180 utilizes the gating policy in order to disable the service data flow, as described in 3GPP TS 23.203 V14.1.0. Details of step S303 are illustrated as step S402 in Fig. 8. One way to implement step S303 is to perform step S102. S304: The PGW 200 applies the gating and sends a request towards the radio access network node 110 to temporarily release the radio resources. Details of step S304 are illustrated as step S403 in Fig. 8. One way to implement step S304 is to perform step S106, and optionally step S104. Sending a request towards the radio access network node 110 should be understood such that at least parts of the information in the request is intended for the radio access network node 110, and that the information may traverse other nodes (e.g. such as the MME 170) before it is received by the radio access network node 110.

S305: The control node 300 optionally informs the client nodes 160a, 160b, 160c that the dedicated radio resources for the group communications session has been released. One way to implement step S305 is to perform step S204.

A second particular embodiment for radio resource management in a group communications system 100 based on at least some of the above disclosed embodiments will now be disclosed in detail with reference to the signalling diagram of Fig. 8 (where WD is short for wireless device, NN is short for radio access network node, and CN is short for control node).

S401: The control node 300 sends a request to the PCRF 180 in a Diameter Rx AA- Request message to disable a unicast service data flow of an ongoing group communications session of the group communications system 100. The request is sent in order for a radio access network node 110 to release unicast radio resources of the ongoing group communications session. One way to implement step S401 is to perform step S202.

S402: The PCRF 180 disables the service data flow by sending a gating control request in a Re-Auth-Request (RAR) message to the PGW 200 for l8 disabling a unicast service data flow of the ongoing group communications session. The gating control request may comprise a PCC rule in which one or more service data flows are disabled. One way to implement step S402 is to perform step S102. S403: The PGW 200 adjusts the bitrate of the EPS bearer by reducing the bitrate that is associated to the service data flow(s) currently under gating control in order to apply gating and sends a corresponding update bearer request towards the MME 170 of the core network node 300 (for further transmission to the radio access network node 100). Sending an update bearer request towards the radio access network node 110 should be understood such that at least parts of the information in the update bearer request is intended for the radio access network node 110, and that the information may traverse other nodes (e.g. such as the MME 170) before it is received by the radio access network node 110. However, the PCRF 180 may, in an alternative to step S403, determine to adjust the bitrate due to the gating request from the control node 300. In such case the PCRF 180 by itself sets a new bitrate in the PCC rule in step S402.

One way to implement step S403 is to perform step S106, and optionally step S104.

S404: The radio access network node 100 receives from the MME the modified bitrate information due to gating and enforces this new bitrate, by adjusting the allocation of the scheduled radio resources.

S405: The client node 160a, 160b, 160c is informed of the modified bitrate due to the current gating control. One way to implement step S405 is to perform step S204.

Fig. 9 schematically illustrates, in terms of a number of functional units, the components of a PGW 200 according to an embodiment. Processing circuitry 210 is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product 1310a (as in Fig. 13), e.g. in the form of a storage medium 230. The processing circuitry 210 may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA).

Particularly, the processing circuitry 210 is configured to cause the PGW 200 to perform a set of operations, or steps, S102-S106, as disclosed above. For example, the storage medium 230 may store the set of operations, and the processing circuitry 210 may be configured to retrieve the set of operations from the storage medium 230 to cause the PGW 200 to perform the set of operations. The set of operations may be provided as a set of executable instructions. Thus the processing circuitry 210 is thereby arranged to execute methods as herein disclosed. The storage medium 230 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.

The PGW 200 may further comprise a communications interface 220 for communications with other nodes, functions, and devices of the

communications system 100. As such the communications interface 220 may comprise one or more transmitters and receivers, comprising analogue and digital components.

The processing circuitry 210 controls the general operation of the PGW 200 e.g. by sending data and control signals to the communications interface 220 and the storage medium 230, by receiving data and reports from the communications interface 220, and by retrieving data and instructions from the storage medium 230. Other components, as well as the related

functionality, of the PGW 200 are omitted in order not to obscure the concepts presented herein. Fig. 10 schematically illustrates, in terms of a number of functional modules, the components of a PGW 200 according to an embodiment. The PGW 200 of Fig. 10 comprises a number of functional modules; a receive module 210a configured to perform step S102, and a send module 210c configured to perform step S106. The PGW 200 of Fig. 10 may further comprise a number of optional functional modules, such as an adjust module 210b configured to perform step S104. In general terms, each functional module 2ioa-2ioc may be implemented in hardware or in software. Preferably, one or more or all functional modules 2ioa-2ioc may be implemented by the processing circuitry 210, possibly in cooperation with the communications interface 220 and/or the storage medium 230. The processing circuitry 210 may thus be arranged to from the storage medium 230 fetch instructions as provided by a functional module 2ioa-2ioc and to execute these instructions, thereby performing any steps of the PGW 200 as disclosed herein. Fig. 11 schematically illustrates, in terms of a number of functional units, the components of a control node 300 according to an embodiment. Processing circuitry 310 is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product 1310b (as in Fig. 13), e.g. in the form of a storage medium 330. The processing circuitry 310 may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA).

Particularly, the processing circuitry 310 is configured to cause the control node 300 to perform a set of operations, or steps, S202-S204, as disclosed above. For example, the storage medium 330 may store the set of operations, and the processing circuitry 310 may be configured to retrieve the set of operations from the storage medium 330 to cause the control node 300 to perform the set of operations. The set of operations may be provided as a set of executable instructions. Thus the processing circuitry 310 is thereby arranged to execute methods as herein disclosed. The storage medium 330 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.

The control node 300 may further comprise a communications interface 320 for communications with other nodes, functions, and devices of the

communications system 100. As such the communications interface 320 may comprise one or more transmitters and receivers, comprising analogue and digital components.

The processing circuitry 310 controls the general operation of the control node 300 e.g. by sending data and control signals to the communications interface 320 and the storage medium 330, by receiving data and reports from the communications interface 320, and by retrieving data and

instructions from the storage medium 330. Other components, as well as the related functionality, of the control node 300 are omitted in order not to obscure the concepts presented herein.

Fig. 12 schematically illustrates, in terms of a number of functional modules, the components of a control node 300 according to an embodiment. The control node 300 of Fig. 12 comprises a request module 310a configured to perform step S202. The control node 300 of Fig. 12 may further comprise a number of optional functional modules, such as an inform module 310b configured to perform step S204. In general terms, each functional module 3ioa-3iob may be implemented in hardware or in software. Preferably, one or more or all functional modules 3ioa-3iob may be implemented by the processing circuitry 310, possibly in cooperation with the communications interface 320 and/or the storage medium 330. The processing circuitry 310 may thus be arranged to from the storage medium 330 fetch instructions as provided by a functional module 3ioa-3iob and to execute these instructions, thereby performing any steps of the control node 300 as disclosed herein.

The control node 300 may be provided as a standalone device or as a part of at least one further device. For example, the control node 300 may be provided in a node of the radio access network 120 or in a node of the core network 130 or in a node of the service network 140. Alternatively, functionality of the control node 300 may be distributed between at least two devices, or nodes. These at least two nodes, or devices, may either be part of the same network part (such as the radio access network or the core network or the service network) or may be spread between at least two such network parts. Some examples of where in the communications system 100 the control node 300 may be provided are illustrated in Fig. 2.

Functionality of the control node 300 may be implemented at the service layer of the protocol stack. In general terms, instructions that are required to be performed in real time may be performed in a device, or node, operatively closer to the radio access network 120 than instructions that are not required to be performed in real time. In this respect, at least part of the control node 300 may reside in the radio access network 120, such as in the radio access network node 110, for cases when embodiments as disclosed herein are performed in real time.

Thus, a first portion of the instructions performed by the control node 300 may be executed in a first device, and a second portion of the of the instructions performed by the control node 300 may be executed in a second device; the herein disclosed embodiments are not limited to any particular number of devices on which the instructions performed by the control node 300 may be executed. Hence, the methods according to the herein disclosed embodiments are suitable to be performed by a control node 300 residing in a cloud computational environment. Therefore, although a single processing circuitry 310 is illustrated in Fig. 11 the processing circuitry 310 may be distributed among a plurality of devices, or nodes. The same applies to the functional modules 3ioa-3iob of Fig. 12 and the computer program 1320b of Fig. 13 (see below).

Fig. 13 shows one example of a computer program product 1310a, 1310b comprising computer readable means 1330. On this computer readable means 1330, a computer program 1320a can be stored, which computer program 1320a can cause the processing circuitry 210 and thereto operatively coupled entities and devices, such as the communications interface 220 and the storage medium 230, to execute methods according to embodiments described herein. The computer program 1320a and/or computer program product 1310a may thus provide means for performing any steps of the PGW 200 as herein disclosed. On this computer readable means 1330, a computer program 1320b can be stored, which computer program 1320b can cause the processing circuitry 310 and thereto operatively coupled entities and devices, such as the communications interface 320 and the storage medium 330, to execute methods according to embodiments described herein. The computer program 1320b and/or computer program product 1310b may thus provide means for performing any steps of the control node 300 as herein disclosed.

In the example of Fig. 13, the computer program product 1310a, 1310b is illustrated as an optical disc, such as a CD (compact disc) or a DVD (digital versatile disc) or a Blu-Ray disc. The computer program product 1310a, 1310b could also be embodied as a memory, such as a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), or an electrically erasable programmable read-only memory (EEPROM) and more particularly as a non-volatile storage medium of a device in an external memory such as a USB (Universal Serial Bus) memory or a Flash memory, such as a compact Flash memory. Thus, while the computer program 1320a, 1320b is here schematically shown as a track on the depicted optical disk, the computer program 1320a, 1320b can be stored in any way which is suitable for the computer program product 1310a, 1310b.

The inventive concept has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended patent claims.

Claims

1. A method for radio resource management in a group communications system (100), the method being performed by a packet data network gateway, PGW (200), the method comprising:

receiving (S102) a gating control request from a Policy and Charging

Rules Function, PCRF (180), for disabling a unicast service data flow of an ongoing group communications session of the group communications system (100); and

sending (S106), in response to having received the gating control request, an update bearer request towards a radio access network node (110) for releasing unicast radio resources of the ongoing group communications session.

2. The method according to claim 1, wherein the gating control request is received per service data flow of the ongoing group communications session.

3. The method according to claim 1 or 2, wherein the update bearer request pertains to at least temporarily releasing the unicast radio resources allocated to the service data flow.

4. The method according to any of the preceding claims, wherein the unicast service data flow is transported using an EPS bearer.

5. The method according to claim 4, further comprising:

adjusting (S104) bitrate of the EPS bearer by reducing bitrate of the unicast service data flow.

6. The method according to claim 4, wherein the gating control request indicates an adjusted bitrate of the EPS bearer by the gating control request having a reduced bitrate of the unicast service data flow.

7. The method according to claim 4, wherein the update bearer request pertains to less than all service data flows of the EPS bearer.

8. The method according to claim 4, wherein the update bearer request pertains to all service data flows of the EPS bearer, and wherein the update bearer request pertains to preserving network connectivity of the EPS bearer whilst releasing all radio resources allocated for the EPS bearer.

9. The method according to any of the preceding claims, wherein a unicast bearer context associated with the unicast service data flow is preserved when the unicast service data flow is disabled.

10. A method for radio resource management in a group communications system (100), the method being performed by a control node (300) of the group communications system (100), the method comprising:

requesting (S202), by sending a request to a Policy and Charging Rules Function, PCRF (180), to disable a unicast service data flow of an ongoing group communications session of the group communications system (100), a radio access network node (110) to release unicast radio resources of the ongoing group communications session.

11. The method according to claim 10, further comprising:

informing (S204) a client node (160a, 160b, 160c) in the group communications system (100) that the unicast radio resources of the ongoing group communications session have been released.

12. A packet data network gateway, PGW (200) for radio resource management in a group communications system (100), the PGW (200) comprising processing circuitry (210), the processing circuitry being configured to cause the PGW (200) to:

receive a gating control request from a Policy and Charging Rules Function, PCRF (180), for disabling a unicast service data flow of an ongoing group communications session of the group communications system (100); and

send, in response to having received the gating control request, an update bearer request towards a radio access network node (110) for releasing unicast radio resources of the ongoing group communications session.

13. A packet data network gateway, PGW (200) for radio resource management in a group communications system (100), the PGW (200) comprising:

processing circuitry (210); and

a storage medium (230) storing instructions that, when executed by the processing circuitry (210), cause the PGW (200) to:

14. A packet data network gateway, PGW (200) for radio resource management in a group communications system (100), the PGW (200) comprising:

a receive module (210a) configured to receive a gating control request from a Policy and Charging Rules Function, PCRF (180), for disabling a unicast service data flow of an ongoing group communications session of the group communications system (100); and

a send module (210c) configured to send, in response to the PGW (200) having received the gating control request, an update bearer request towards a radio access network node (110) for releasing unicast radio resources of the ongoing group communications session.

15. A control node (300) for radio resource management in a group communications system (100), the control node (300) comprising processing circuitry (310), the processing circuitry being configured to cause the control node (300) to: request, by sending a request to a Policy and Charging Rules Function, PCRF (180), to disable a unicast service data flow of an ongoing group communications session of the group communications system (100), a radio access network node (110) to release unicast radio resources of the ongoing group communications session.

16. A control node (300) for radio resource management in a group communications system (100), the control node (300) comprising:

processing circuitry (310); and

a storage medium (330) storing instructions that, when executed by the processing circuitry (310), cause the control node (300) to:

request, by sending a request to a Policy and Charging Rules Function, PCRF (180), to disable a unicast service data flow of an ongoing group communications session of the group communications system (100), a radio access network node (110) to release unicast radio resources of the ongoing group communications session.

17. A control node (300) for radio resource management in a group communications system (100), the control node (300) comprising:

a request module (310a) configured to request, by sending a request to a Policy and Charging Rules Function, PCRF (180), to disable a unicast service data flow of an ongoing group communications session of the group communications system (100), a radio access network node (110) to release unicast radio resources of the ongoing group communications session.

18. A computer program (1320a) for radio resource management in a group communications system (100), the computer program comprising computer code which, when run on processing circuitry (210) of a packet data network gateway, PGW (200), causes the PGW (200) to:

receive (S102) a gating control request from a Policy and Charging Rules Function, PCRF (180), for disabling a unicast service data flow of an ongoing group communications session of the group communications system (100); and

send (S106), in response to having received the gating control request, an update bearer request towards a radio access network node (110) for releasing unicast radio resources of the ongoing group communications session.

19. A computer program (1320b) for radio resource management in a group communications system (100), the computer program comprising computer code which, when run on processing circuitry (310) of a control node (300), causes the control node (300) to:

request (S202), by sending a request to a Policy and Charging Rules Function, PCRF (180), to disable a unicast service data flow of an ongoing group communications session of the group communications system (100), a radio access network node (110) to release unicast radio resources of the ongoing group communications session.

20. A computer program product (1310a, 1310b) comprising a computer program (1320a, 1320b) according to at least one of claims 18 and 19, and a computer readable storage medium (1330) on which the computer program is stored.