WO2013091705A1

WO2013091705A1 - Methods and apparatuses for session establishment with policy control between mobile and fixed networks

Info

Publication number: WO2013091705A1
Application number: PCT/EP2011/073778
Authority: WO
Inventors: Tuija Helena Hurtta
Original assignee: Nokia Siemens Networks Oy
Priority date: 2011-12-22
Filing date: 2011-12-22
Publication date: 2013-06-27

Abstract

It is provided a method for establishing a policy control session between a mobile network and a fixed access network, comprising receiving, from a gateway, information indicating that a user equipment (UE) of a user of a mobile network is attaching to a base station connected to a fixed broadband access network; determining, based on the received information indicating that the UE is attaching to the base station, whether there is at least one packet data connection between at least one other UE and the base station; and establishing a policy control session related to the base station with a policy control function of the fixed broadband access network if there are no packet data connections between the at least one other UE and the base station.

Description

Title

METHODS AND APPARATUSES FOR SESSION ESTABLISHMENT WITH POLICY CONTROL BETWEEN MOBILE AND FIXED NETWORKS

Field of the invention

The present invention relates to methods, apparatuses, a system, and a computer

program product related to session establishment with policy control. More particularly, the present invention relates to methods, apparatuses, a system, and a computer program product for establishing a policy control session between mobile and fixed networks.

Background of the invention

The 3^rd generation partnership project (3GPP) is studying and standardising interworking between 3GPP mobile networks and fixed broadband networks in collaboration with

Broadband Forum (BBF). 3GPP technical report (TR) 23.839 addresses architectural aspects of the interworking, such as policy and Quality of Service (QoS) control between the 3GPP mobile network and Broadband Forum (BBF) network architectures. An

example use case of such interworking is that a User Equipment (UE) accesses a 3rd

Generation (3G) or Long Term Evolution (LTE) access network, e.g. via a femto/pico base station located at home or in enterprise premises. The 3G/LTE base station may be connected to a 3GPP Evolved Packet Core (EPC) network via a fixed access (e.g. via

Digital Subscriber Line (DSL) or cable when connected from home). In this case the user traffic is routed from the fixed access to the 3GPP EPC.

The policy control architecture for 3GPP and BBF networks comprises policy control and enforcement functions on the user plane for both networks. In the 3GPP mobile core network, the policy control function may be a Policy Control and Charging Rules Function (PCRF) and the policy enforcement function may be a Policy and Charging Enforcement Function (PCEF). Generally, policy control may comprise a process whereby the PCRF indicates to the PCEF how to control an Internet Protocol Connectivity Access Network (IP CAN) bearer. Policy control may comprise QoS control and/or gating control. The 3GPP policy and charging control architecture and its functions are described in more detail in 3GPP Technical Specification (TS) 23.203. In the BBF network, the policy control function may be a Broadband Policy Control Function (BPCF) and the policy enforcement function may be a Broadband Network Gateway (BNG). In scenarios of 3GPP TR 23.839, interworking between the above policy control functions may happen over a Diameter protocol based interface, such as an S9a or S9* interface or a similar interface. When a Diameter session is established over the S9a interface, the fixed access network (BPCF) is able to associate the I P traffic plane (tunnel) used by the 3GPP UE with the S9a session towards the PCRF.

Fig. 1 is a block diagram of nodes in the policy control architecture of a mobile core network 100 and fixed broadband network 102 relevant to the present invention. The mobile core network 100 may comprise e.g. an Evolved Packet Core Network (EPC). A mobile radio access network 101 , e.g. a 3GPP evolved Universal Mobile

Telecommunications System (UMTS) Terrestrial Radio Access Network (e-UTRAN) may be connected to the mobile core network 100. A PCRF 1021 may install policy control and charging rules in a PCEF 1022 over a Diameter-based Gx interface. The PCEF 1022 may reside in a gateway, e.g. a Packet Data Network Gateway (PDN GW/P-GW). Alternatively, the PCRF may install policy and charging control rules in a Bearer Binding and Event Reporting Function (BBERF) 1028 over a Diameter-based Gxx interface. The Gxx interface or reference point corresponds to Gxa and Gxc reference points, as defined in 3GPP TS 23.402. A mobility management entity 1023, e.g. a 3GPP Mobility Management Entity (MME) or a Serving General Packet Radio Service (GPRS) Support node (SGSN) may be connected to the P-GW 1022 via a Serving Gateway (S-GW) and to the mobile radio access network 101 via an S1 interface. In the policy control architecture according to Fig. 1 , a home subscriber server (HSS) may store subscription related data, for example an International Mobile Subscriber Identity (IMSI) and Mobile Station International Subscriber Directory Number (MSISDN). A subscription profile repository (SPR) may store subscriber and subscription related information needed for subscription-based policies and IP CAN bearer level policy control and charging rules provided by the PCRF. Examples of subscription related information provided by the SPR are subscriber's allowed services and subscribed guaranteed bandwidth quality of service. An online charging system (OCS) supports charging related functionalities such as rating, subscriber account balance management and charging transaction control. The OCS may for example support online bearer charging towards access and core network entities and online charging of applications that are provided via service nodes outside the core network. According to scenarios of 3GPP TR 23.839, when a UE 103 accesses 3GPP mobile network operator's I P services, e.g. IP Multimedia Subsystem (IMS) services via e.g. a 3GPP femto base station H(e)NB 1025, a BPCF 1024 in the fixed broadband network 102 may perform admission control based on bandwidth requirements and QoS attributes of new or modified service data flows of the UE 103. In such a case the function of the S9a interface is to convey information from the PCRF 1021 to the BPCF 1024 for the admission control. In a roaming scenario, the S9a interface may also provide transfer of QoS and policy information from a visited PCRF (V-PCRF) to the BPCF 1024. In such a scenario, a home PCRF (H-PCRF) may initiate an S9 session to the V-PCRF that, in turn, initiates the S9a session with the BPCF 1024. The home Public Land Mobile Network (home PLM N) may thus provide policies in the visited PLM N that take into account that the UE 103 may access the 3GPP mobile core network 100 via the H(e)NB 1025 connected to the fixed broadband network 102. More detailed information of the nodes illustrated in Fig. 1 and their functions can be found in the above mentioned technical report 3GPP TR 23.839.

The current 3GPP standardized way of establishing a policy control session over the S9a interface between the policy control function (PCRF) of the 3GPP mobile core network and the policy control function (BPCF) of the fixed broadband access network when the UE attaches to a 3GPP base station connected via the fixed broadband access network may comprise using a single S9a Diameter session for all UEs that request services via the same 3GPP base station. The S9a session may thus represent an individual base station and may be established for the duration of the base station being powered up and operatively connected to a H(e)NB gateway (H(e)NB GW) or to the MM E.

The policy control session over the S9a interface for the 3GPP femto/pico or macro base station (H(e)NB or (e)NB) may be established once when the first UE connected to the H(e)NB/(e)NB attaches to the networks. The PCRF may determine that the UE is connected to a H(e)NB/(e)NB when it receives tunnel information in the I P CAN session establishment message over the Gx interface or in the GW control session establishment message over a Gxc interface.

Thus, according to the prior art, in scenarios where the UE attaches to a H(e)N B/(e)NB, there may be one policy control session over the S9a interface for all the UEs attaching via the same H(e)NB/(e)NB. This S9a session may be established when the I P CAN session on the Gx interface for the first UE connected to the H(e)NB/(e)NB is established. This S9a session may be released when the I P CAN session on the Gx interface for the .

4 last UE attached via the H(e)N B/(e)NB is terminated. The current scenarios for S9a session establishment according to the 3GPP TR 23.839 do not take into account mobility scenarios where the PDN connection or PDP context for the UE may remain active although the UE is no longer served by the H(e)NB/(e)NB. In such a case, also the Diameter session on Gx between the PDN GW and PCRF remains active when the UE moves between femto base stations or between femto and macro network base stations.

As a consequence, it has not been addressed by the current specifications how the policy control interworking between the mobile core network and fixed access network is managed in case of mobility of UEs within femto base stations or between femto and macro base stations.

Summary of the invention An object of the present invention is to provide methods, apparatuses, a system and a computer program product for improved policy control interworking which takes into account mobility of the UE.

In a first embodiment, the present invention is directed to a method for establishing a policy control session. The method comprises receiving, from a gateway, information indicating that a user equipment (UE) of a user of a mobile network is attaching to a second base station connected to a fixed broadband access network; determining, based on the received information indicating that the UE is attaching to the second base station, whether there is at least one packet data connection between at least one other U E and the second base station; and establishing a policy control session related to the second base station, with a policy control function of the fixed broadband access network if there are no packet data connections between the at least one other UE and the second base station. The method may also comprise detecting, by a policy control function of the mobile network, a handover of the UE from a first base station to the second base station;

determining, by the policy control function of the mobile network, whether there is at least one packet data connection between at least one other UE and the first base station; and releasing a policy control session related to the first base station, from the policy control function of the fixed broadband access network if there are no packet data connections between the at least one other UE and the first base station. The method may be performed by a policy control function of the mobile network.

The method may additionally comprise establishing an event trigger for reporting at least one event related to mobility of U Es and transmitting information of the event trigger to the gateway.

In the method according to the first embodiment, the information indicating that the UE is attaching to the second base station may comprise, without limitations, one of a base station identifier, a cell identifier and a service area identifier of the second base station. The information may be provided by a mobility management entity. The mobility management entity may comprise for example a 3GPP Mobility Management Entity

(MME) or a Serving GPRS Support Node (SGSN). The information indicating that the UE is attaching to the second base station may comprise, without limitations, one of an indication that the UE is attaching to a femto base station and an indication that the UE is attaching to a macro network base station.

In the method according to the first embodiment, the information indicating that the UE is attaching to the second base station may be received via one of a Gx interface, a Gxc interface and a Gxx interface of 3GPP mobile core network. The information may be received at establishment of a Packet Data Network (PDN) connection for the UE. The policy control session may be established over an S9a interface between policy control entities of the mobile network and the fixed broadband access network.

In the method according to the first embodiment, the gateway may comprise, but is not limited to, at least one of a 3GPP Policy and Charging Enforcement Function (PCEF), a Packet Data Network Gateway (PDN GW) and a Bearer Binding and Event Reporting Function (BBERF). The policy control function of the mobile network may comprise for example a 3GPP Policy and Charging Rules Function (PCRF).

In the method according to the first embodiment, the receiving of the information indicating that the UE is attaching to the second base station may be performed responsive to sending a request to the gateway requesting information related to attachment of UEs to the network via a base station.

In the method according to the first embodiment, the information of the event trigger may be used to configure the gateway to transmit the information indicating that the UE is attaching to the second base station, to the policy control function of the mobile network, if an event corresponding to the information of the event trigger is detected. In a second embodiment, the present invention is directed to a method comprising receiving information of an event trigger for reporting at least one event related to mobility of U Es; receiving, from a mobility management entity, information indicating that user equipment of a user of a mobile network is attaching to a second base station connected to a fixed broadband access network; determining that the information indicating that the user equipment of a user of the mobile network is attaching to the second base station corresponds to the information of the event trigger; and transmitting the information indicating that the UE is attaching to the second base station to a policy control function of the mobile network.

According to the second embodiment, the method may further comprise transmitting to the policy control function of the mobile network information of a handover of the UE from a first base station to the second base station.

The method may be performed by a gateway. The gateway may comprise at least one of a 3GPP Policy and Charging Enforcement Function (PCEF), a Packet Data Network Gateway (PDN GW) and a Bearer Binding and Event Reporting Function (BBERF). In the method of the second embodiment, the mobility management entity may comprise a 3GPP Mobility Management Entity (MME) or a Serving GPRS Support Node (SGSN). The policy control function of the mobile network may comprise a 3GPP Policy and Charging Rules Function (PCRF). In the method of the second embodiment, the information indicating that the UE is attaching to the second base station may be transmitted to the policy control function of the mobile network via e.g. one of a Gx interface, a Gxc interface and a Gxx interface. The information indicating that the UE is attaching to the second base station may be received at establishment of a Packet Data Network (PDN) connection for the UE.

In the method according to the second embodiment, the information indicating that the UE is attaching to the second base station may be transmitted responsive to receiving a request for information related to attachment of UEs from the policy control function of the mobile network.

The method according to the second embodiment may further comprise configuring, based on the information of the event trigger, transmission of the information indicating that the UE is attaching to the second base station to the policy control function of the mobile network, if an event corresponding to the event trigger is detected.

The method according to the second embodiment may further comprise sending a request to the mobility management entity, requesting information of the mobility events as defined in the information of the event trigger.

In a third embodiment, the present invention is directed to a method, comprising receiving, from a gateway, a request requesting information of events related to mobility of UEs as defined in an event trigger provided by a policy control function of a mobile network; and transmitting, to the gateway, information indicating that a UE is attaching to a second base station connected to a fixed broadband network, as a response of receiving the request.

The method of the third embodiment may further comprise transmitting to the gateway information of a handover of the UE from a first base station to the second base station.

The method may be performed by a mobility management entity comprising for example a 3GPP Mobility Management Entity (MME) or a Serving GPRS Support Node (SGSN). In the method of the third embodiment, the information indicating that the UE is attaching to the second base station may comprise one of an indication that the UE is attaching to a femto base station and an indication that the U E is attaching to a macro network base station. The information may be transmitted at establishment of a Packet Data Network (PDN) connection for the UE.

In a fourth embodiment, the present invention is directed to an apparatus comprising a receiver or means for receiving which may be configured to receive, from a gateway, information indicating that a UE of a user of a mobile network is attaching to a second base station connected to a fixed broadband access network; a processor or means for processing which may be configured to determine, based on the received information indicating that the UE is attaching to the second base station, whether there is at least one packet data connection between at least one other UE and the second base station; and a transmitter or means for transmitting which may be configured to establish a policy control session related to the second base station, with a policy control function of the fixed broadband access network if there are no packet data connections between the at least one other UE and the second base station. In the apparatus according to the fourth embodiment, the processor or means for processing may be further configured to detect a handover of the UE from a first base station to the second base station; the processor or means for processing may be further configured to determine whether there is at least one packet data connection between at least one other UE and the first base station; and the transmitter or means for transmitting may be further configured to release a policy control session related to the first base station, from the policy control function of the fixed broadband access network if there are no packet data connections between the at least one other UE and the first base station. In the apparatus according to the fourth embodiment, the processor or means for processing may be further configured to establish an event trigger for reporting at least one event related to mobility of UEs; and the transmitter or means for transmitting may be further configured to transmit information of the event trigger to the gateway. The apparatus may be a policy control function of the mobile network.

Further, according to the fourth embodiment, the information indicating that the UE is attaching to the second base station may be provided by a mobility management entity. The mobility management entity may comprise for example a 3GPP Mobility Management Entity (MME) or a Serving GPRS Support Node (SGSN).

According to the fourth embodiment, the receiver or means for receiving of the apparatus may be further configured to receive the information indicating that the UE is attaching to the second base station via e.g. one of a Gx interface, a Gxc interface, and a Gxx interface of 3GPP mobile network. The receiver or means for receiving may be further configured to receive the information indicating that the UE is attaching to the second base station at establishment of a Packet Data Network (PDN) connection for the UE.

According to the fourth embodiment, the transmitter or means for transmitting of the apparatus may be further configured to establish the policy control session over an S9a interface between policy control entities of a 3GPP mobile core network and a fixed broadband access network.

According to the fourth embodiment the receiver or means for receiving may be further configured to receive the information indicating that the UE is attaching to the second base station responsive to sending a request for information related to attachment of UEs, to the gateway. In the apparatus according to the fourth embodiment, the information of the event trigger may be used to configure the gateway to transmit the information indicating that the UE is attaching to the second base station, to the policy control function of the mobile network, if an event corresponding to the information of the event trigger is detected.

In a fifth embodiment, the present invention is directed to an apparatus comprising a receiver or means for receiving configured to receive information of an event trigger for reporting at least one event related to mobility of UEs; the receiver or means for receiving being further configured to receive, from a mobility management entity, information indicating that a UE of a user of a mobile network is attaching to a second base station connected to a fixed broadband access network; a processor or means for processing configured to determine that the information indicating that the UE of the user of the mobile network is attaching to a second base station corresponds to the information of the event trigger; and a transmitter or means for transmitting configured to transmit the information indicating that the UE is attaching to the second base station, to a policy control function of the mobile network.

In the apparatus according to the fifth embodiment, the transmitter or means for transmitting may be further configured to transmit to the policy control function of the mobile network information of a handover of the UE from a first base station to the second base station.

The apparatus may be a gateway comprising at least one of a 3GPP Policy and Charging Enforcement Function (PCEF), a Packet Data Network Gateway (PDN GW) and a Bearer Binding and Event Reporting Function (BBERF).

In the apparatus according to the fifth embodiment, the transmitter or means for transmitting may be further configured to transmit the information indicating that the UE attaching to the second base station to the policy control function of a mobile network via e.g. one of a Gx interface, a Gxc interface and a Gxx interface.

In the apparatus according to the fifth embodiment, the transmitter or means for transmitting and the receiver or means for receiving may be configured to transmit and receive, respectively, the information indicating that the UE is attaching to the second base station at establishment of a Packet Data Network (PDN) connection for the UE. In the apparatus according to the fifth embodiment, the transmitter or means for transmitting may be configured to transmit the information indicating that the UE is attaching to the second base station responsive to receiving a request for information related to attachment of UEs from the policy control function of the mobile network.

In the apparatus according to the fifth embodiment, the apparatus may be further configured to transmit, based on the information of the event trigger, the information indicating that the UE is attaching to the second base station, to the policy control function of the mobile network, if an event corresponding to the information of the event trigger is detected.

The apparatus according to the fifth embodiment may be further configured to send a request to the mobility management entity, requesting information of the mobility events as defined in the information of the event trigger.

In a sixth embodiment, the present invention is directed to an apparatus comprising a receiver or means for receiving configured to receive, from a gateway, a request requesting information of events related to mobility of U Es as defined in information of an event trigger provided by a policy control function of a mobile network; and a transmitter or means for transmitting configured to transmit, to the gateway, information indicating that a UE is attaching to a second base station, as a response of receiving the request.

In the apparatus according to the sixth embodiment, the transmitter or means for transmitting may be further configured to transmit to the gateway information of a handover of the UE from a first base station to the second base station. The information may be one of a base station identifier, a cell identifier and a service area identifier of the second base station.

The apparatus according to the sixth embodiment may be a mobility management entity (2023), comprising for example a 3GPP Mobility Management Entity (MME) or a Serving GPRS Support Node (SGSN).

In the apparatus according to the sixth embodiment, the transmitter or means for transmitting may be configured to transmit the information indicating that the UE is attaching to the second base station at establishment of a Packet Data Network (PDN) connection for the U E. In a seventh embodiment, the present invention is directed to a system comprising apparatuses according to the fourth, fifth and sixth embodiment.

In an eighth embodiment, the present invention is directed to a computer program product for performing methods according to the first, second and third embodiment when run on a processor.

To achieve the above object, the present invention utilizes an enhanced Gx or Gxx interface for reporting mobility events of UEs to the policy control function of the mobile core network so that the policy control function may manage policy control sessions over the S9a interface even if the PDN connection or PDP context and thus the Gx or Gxx Diameter sessions for the UE remain active. In addition, signaling between the mobility management entity and the policy enforcement function of the mobile core network is enhanced with support for reporting mobility events based on a rule or a trigger, to achieve more dynamic management of policy control sessions.

Hence, the present invention takes into account mobility scenarios in which the UE moves within femto base stations or between femto and macro network base stations, which is currently not addressed by the related specifications. Accordingly, it enables enhanced policy control session management between a mobile core network and a fixed access network.

It is to be understood that any of the above modifications can be applied singly or in combination to the respective aspects to which they refer, unless they are explicitly stated as excluding alternatives.

Brief description of the drawings

For a more complete understanding of exemplary embodiments of the present invention, reference is now made to the following descriptions taken in connection with the accompanying drawings in which:

Fig. 1 is a block diagram of nodes in a policy control architecture of a mobile core network and a fixed broadband access network relevant to the invention; Fig. 2 is a block diagram of a system according to an embodiment of the invention; Fig. 3 is a signaling flow illustrating an embodiment of a procedure for establishing a policy control session during attachment of a UE to a base station;

Fig. 4 is a signaling flow illustrating an embodiment of a procedure for establishing a policy control session in case of mobility of the UE;

Fig. 5 is a block diagram of an embodiment of a policy control function establishing a policy control session; Fig. 6 is a flow diagram of an embodiment of a procedure for establishing a policy control session;

Fig. 7 is a block diagram of an embodiment of a policy control function releasing a policy control session;

Fig. 8 is a flow diagram of an embodiment of a procedure for releasing a policy control session;

Fig. 9 is a block diagram of an embodiment of a policy enforcement function;

Fig. 10 is a flow diagram of an embodiment of a procedure for enforcing an event trigger;

Fig. 1 1 is a block diagram of an embodiment of a mobility management entity; Fig. 12 is a flow diagram of an embodiment of a procedure for providing information of mobility events of a UE.

Detailed description The example embodiments of the present invention and its potential advantages are described herein below by way of example with reference to the accompanying drawings.

Fig. 1 is a block diagram of nodes in the policy control architecture of a mobile core network 100 and a fixed broadband access network 102 relevant to the present invention.

An I P CAN session establishment on Diameter Gx interface may trigger the PCRF 1021 to initiate the policy control session establishment over the Diameter S9a interface. As a result of the S9a session establishment, the fixed broadband access network 102 may associate the I P traffic plane of the UE 103 with the S9a session towards the PCRF 1021 . There may be a single S9a Diameter session with the BPCF 1024 for all the UEs that request services via the same H(e)NB/(e)NB 1025. The S9a Diameter session may be established when the first UE connected to the H(e)NB/(e)N B 1025 attaches to the networks. This S9a Diameter session may be released when the I P CAN session on the Gx interface for the last UE attached via the H(e)N B/(e)NB 1025 is terminated.

Fig. 2 is a block diagram of a system according to an embodiment of the present invention. The system may comprise a policy control function 2021 , a gateway comprising a policy enforcement function 2022, and a mobility management entity 2023 in a mobile core network 200; a policy control function 2024 in a fixed access network 202; a

Diameter interface between the gateway 2022 and the policy control function 2021 ; and a Diameter interface between the policy control function 2021 in the mobile core network 200 and the policy control function 2024 in the fixed access network 202. A first base station (H(e)NB1 ) 2025 and a second base station (H(e)NB2) 2026 may be connected to the mobile core network 200 via the fixed access network 202. The first base station H(e)NB1 2025 and the second base station H(e)NB2 2026 may be operatively connected to the fixed access network 202, hence, there may be also other network entities such as gateways and controllers, etc. involved on the data path between the first 2025 and the second base station 2026 and the fixed access network 202. A UE 203 may access and use I P services such as IMS services provided by the operator of the mobile core network operator 200 via the H(e)NB1 2025 over the connection provided by the fixed access network 202.

According to some embodiments of the invention, the mobile core network 200 may comprise a 3GPP mobile core network, e.g. Evolved Packet Core network (EPC). The fixed access network 202 may be an access network defined by the Broadband Forum. The fixed access network may comprise, but is not limited to, copper based, optical, hybrid or fiber based accesses providing broadband connection. Examples of such networks are DSL, hybrid FFTx/ADS LA/DSL, Ethernet or passive optical networks (PON). The base stations 2025 and 2026 may be femto or pico base stations, e.g. H(e)NB elements as defined by 3GPP, or they may also be macro base stations, e.g. (e)NBs as defined by 3GPP. They may be of femto or pico or macro type base stations

independently from each other. The user equipment (UE) 203 may be any device, apparatus, unit or means by which a user or subscriber may experience services from an access network, such as a mobile phone, personal digital assistant PDA, a computer, etc. The policy control function 2021 may comprise e.g. a 3GPP Policy Control and Charging Rules Function (PCRF). The policy enforcement function 2022 may comprise e.g. a 3GPP Policy and Charging Enforcement Function (PCEF) located in a gateway (GW), e.g. 3GPP PDN GW. The mobility management entity 2023 may comprise e.g. a 3GPP Serving GPRS Support node (SGSN) or Mobility Management Entity (MME). The architecture of the mobile core network 200 may comprise architecture as that shown in Fig. 1. The PCRF 2021 may be responsible for providing policy control and charging rules for the mobile core network 200. The policy control and charging rules may be enforced by the GW/PCEF 2022. In some embodiments, the enforcement and gateway functions of the GW/PCEF 2022 may be embodied in different entities or in the same entity. The communication between the PCRF 2021 and GW/PCEF 2022 may be based on the Diameter protocol and happen via a Gx interface. The Gx interface may be as defined in 3GPP TS 29.212 and TS 23.203.

The PCRF 2021 of the mobile core network 200 may be operatively connected to the BPCF 2024 of the fixed broadband network 202 to exchange control commands. These commands may relate to policy control and/or charging. The interface or reference point between these functions may be a 3GPP S9a interface.

According to some embodiments of the invention, when the UE 203 accesses services in the mobile core network 200, a traffic channel from the UE 203 or the H(e)NB1 2025 connected to the fixed access network 202 may be I P tunneled from the fixed access network 202 to the mobile core network 200, e.g. through a Broadband Remote Access Server (BRAS) or Broadband Network Gateway (BNG) 2027 in the fixed access network 202. There may be also other gateways 2029 on the data path between the fixed access network 202 and the GW/PCEF 2022, such as a security gateway (SeGW) or a H(e)NB gateway of the mobile core network 200. The SeGW is a network element which may connect H(e)NBs to the operator's core network after successful mutual authentication between the H(e)NB and the SeGW. The E-UTRAN architecture may also deploy a Home eNB Gateway (HeNB GW) to allow a connection over an S1 interface between the HeNB and the EPC.

According to the present invention, at the time of the first access of the UE 203 to the networks, a PDN connection or PDP context and a related Gx session between the

GW/PCEF 2022 and the PCRF 2021 may be created. In a case the UE 203 moves from the H(e)NB1 2025 to the H(e)NB2 2026 and there is a handover of the UE 203 between the two H(e)NBs, the MME 2023 may receive information of the mobility from e.g. the source H(e)NB 2025 of the handover or a H(e)NB GW automatically or by requesting it. The MME 2023 may forward the information of the mobility of the UE 203 to the

GW/PCEF 2022 which in turn may forward it to the PCRF 2021 . This information may identify the base station H(e)NB2 2026 to which the U E 203 is attaching and it may be in the form of a base station identifier, e.g. a H(e)NB ID. It may also be a Cell I D or a Service Area I D. Further, the information may be an indicator indicating mobility of the UE 203 between H(e)NBs or (e)NBs, for example a "femto to femto mobility" or "femto to macro mobility" indicator.

Thus, the GW/PCEF 2022 may receive the information of the mobility of the UE 203 from the MME 2023. This information may be forwarded to the PCRF 2021 for example at I P CAN session modification procedure. In some embodiments, the information may be included in an indication of IP CAN session modification message. In some embodiments, the information may be included in another message using Diameter protocol. This way the PCRF 2021 may become aware that mobility of the UE 203 has happened and the UE 203 is no longer served by the H(e)NB1 2025.

The Diameter session between the GW/PCEF 2022 and the PCRF 2021 on the Gx interface may have been established when the UE 203 attached via the first base station H(e)NB1 2025. Based on the existing Diameter session, the PCRF 2021 may be aware that the UE 203 was connected to the H(e)NB1 2025 before the handover, and that the UE 203 is handed over from the first base station H(e)NB1 2025 to the second base station H(e)NB2 2026. This Diameter session on the Gx interface remains active if the UE 203 moves from the H(e)NB1 2025 to the H(e)NB2 2026.

According to an embodiment of the invention, the GW/PCEF 2022 may inform the PCRF 2021 about the mobility of the UE 203 over the Gx interface. For example, the existing IP CAN session modification procedure may be modified to transfer the mobility information from the GW/PCEF 2022 to the PCRF 2021.

According to an embodiment of the invention, after receiving the information indicating that the UE 203 is attaching to the H(e)NB2 2026 in form of e.g. the H(e)NB2 I D, the PCRF 2021 may determine, based on the information, whether there are already other UEs connected to the H(e)NB2 2026 in addition to the UE 203. The PCRF 2021 may determine this based on information it received at the time of establishment of a PDN connection or PDP context and the corresponding Gx session for the other UEs connected to the H(e)NB2 2026. The information of the PDN connections or PDP contexts for the other UEs may be stored in an internal or external memory or means for storing. If there are no existing connections for the other UEs to the H(e)NB2 2026, the PCRF 2021 may establish a policy control session specific for the H(e)NB2 2026 on the S9a interface towards the BPCF 2024. If, based on the determining, there is already an existing connection for another UE at the H(e)NB2 2026, the PCRF 2021 may modify or update the existing S9a session which was established at H(e)NB2 2026 with information relating to the UE 203. According to an embodiment of the invention, since the PCRF 2021 has the information from which base station the UE 203 has been handed over, i.e. in this case from the first base station H(e)NB1 2025, it may determine whether there are still other UEs connected to the H(e)NB1 2025 which may no longer serve the UE 203. If there are no other UEs connected to the H(e)NB1 2025, the PCRF 2021 may release the policy control session specific for the H(e)NB1 2025 on the S9a Diameter interface towards the BPCF 2024.

Details of the apparatuses and methods of the PCRF 2021 , the GW/PCEF 2022 and the MME 2023 according to some embodiments of the invention are explained with respect to Figs. 5 to 12.

Fig. 3 illustrates signaling between the nodes of the mobile core network 200 for establishing a policy control session on the S9a interface during the IP CAN Session establishment according to an embodiment of the present invention. It is assumed that the PDN connection or PDP context and the related Gx session are created for the first access of a UE (not shown) to a femto or macro base station (not shown).

In step S301 , a gateway control session establishment procedure may be initiated according to standard procedures. In step S302, the GW/PCEF 2022 may receive information from a Bearer Binding and Event Reporting Function (BBERF) 2028 of the mobile core network 200 identifying the base station, e.g. an LTE HeNB/eN B to which the UE is attached.

In some embodiments, the GW/PCEF 2022 may receive the information from the MME or SGSN, for example in a case when GPRS Tunnelling Protocol (GTP) based S5 interface is used in LTE access between the S-GW and P-GW and therefore BBERF 2028 is not relevant. In some embodiments, the information may be included in the I P CAN session signaling. The information may comprise an identifier of the base station, e.g. H(e)NB I D or (e)NB ID. It may also comprise a Cell ID or a Service Area I D. Further, the information may be a "macro" or "femto" indication. If the "macro" or "femto" indicator is used, the MME or SGSN (not shown) may determine whether the UE is served by a macro or femto base station and provide this information to the GW/PCEF 2022. In case another indicator e.g. H(e)NB ID or HNB I D, Cell I D or a Service Area I D is used, the PCRF 2021 may determine based on the indicator whether the UE is served by a macro or femto base station.

In step S303, the GW/PCEF 2022 may transmit the information indicating that the UE is attaching to the base station to the PCRF 2021 . In a roaming case, the information may be transmitted to a visited PCRF which may act as a proxy between the home PCRF and the PCEF (GW) 2022. In some embodiments, the BBERF 2028 may transmit the information indicating that the UE is attaching to the base station directly to the PCRF 2021. In some embodiments, the PCRF 2021 may request information on attachment of users or user equipment (UE) to a base station, and the GW/PCEF 2022 or BBERF 2028 may transmit the information indicating that the U E is attaching to the base station to the PCRF 2021 as a response to the request.

The PCRF 2021 may use the received information indicating that the UE is attaching to a base station in step S307 to determine whether there are already existing connections for other UEs to the base station to which the UE identified in the information is attached. The PCRF 2021 may determine this based on information it received at the time of

establishment of the PDN connection or PDP context and the related Gx session for the other UEs, as explained above. The information of the PDN connections for the other UEs may be stored in an internal or external memory or means for storing of the PCRF 2021. If there are no existing connections for the other UEs, the PCRF 2021 may establish a policy control session on the S9a Diameter interface towards the BPCF 2024 in the fixed access network 202. If, based on the determining, there is already an existing connection for at least one other U E to the base station identified in the received information, the PCRF 2021 may modify or update the existing S9a session relating to this base station with information relating to the U E.

The PCRF 2021 may receive further information of mobility of the UEs within femto base stations, from femto to macro and/or from macro to femto base stations, by establishing a relevant event trigger or a policy rule and instructing the GW/PCEF 2022 or the BBERF 2028, if applicable, in step S310 to report events related to the corresponding event trigger. Thus, the PCRF 2021 may send (step S310) information of the event trigger to the GW/PCEF 2022, which information may define the events to be reported to the PCRF 2021. The event trigger or policy rule may comprise for example at least one trigger for one or more of the following events:

- UE moves within femto base stations;

- UE moves from a femto to a macro base station; and

- UE moves from a macro to a femto base station.

The implementation of establishing such an event trigger may follow standardized procedures.

The GW/PCEF 2022 or BBERF 2028 may use the information of the event trigger received in step S310 to detect events as defined in the event trigger information. If the GW/PCEF 2022 or BBERF 2028 detects an event corresponding to the information of the event trigger, e.g. that the UE attaches to a base station, it may transmit the information to the PCRF 2021. The GW/PCEF 2022 may also be configured to request from the

MME/SGSN 2023 information of the above mobility events. In subsequent signaling from the PCRF 2021 to the GW/PCEF 2022 or BBERF 2028, the PCRF 2021 may provide modifications on the set of the event triggers. Fig. 4 illustrates signaling between the nodes of the mobile core network 200 for establishing, modifying and/or releasing a policy control session on the S9a interface during the I P CAN Session modification according to an embodiment of the invention. In Fig. 4, steps S401 and S402 may comprise standard Application Function (AF) session signaling in which an AF may provide service information to the PCRF 2021 . The

Application Function may be an element offering applications that require dynamic policy and/or charging control over the I P-CAN user plane behaviour. The AF may communicate with the PCRF 2021 to transfer dynamic session information, required for PCRF decisions as well as to receive IP-CAN specific information and notifications about I P-CAN bearer level events. One example of an AF is a Proxy Call Session Control Function (P-CSCF) of the I P Multimedia Core Network (IM CN) subsystem.

In step S403, the GW (PCEF) 2022 may receive information identifying the base station e.g. an LTE HeNB or eNB or a 3G HNB or NodeB to which the UE is attaching. Although it is shown in Fig. 4 that the information identifying the base station is received from the BBERF 2028, in some embodiments, the GW/PCEF 2022 may receive the information from the MME or SGSN, if the BBERF is not used. In some embodiments, the information may be included in a modified IP CAN session modification signaling. In some embodiments, the information may comprise a type of the base station, e.g. a femto or macro network base station. The information may also comprise an identifier of the base station, e.g. a H(e)NB ID / HNB ID. It may also comprise a Cell ID or a Service Area ID of the cell as explained above. Further, the information may comprise an indication that the UE is attaching to the H(e)NB or the macro base station due to mobility, e.g. an indication of that the UE has moved or has been handed over from a femto base station to another femto base station, from a femto to a macro base station or from a macro to a femto base station. The relevant source and target base stations of the handover may be identified by at least one of the above identifiers. In some embodiments, the information may be in form of a newly defined "femto to femto", "femto to macro" or "macro to femto" mobility indication.

In some embodiments, when the handover of the UE between the base stations is initiated, the MME/SGSN may receive information of the mobility from e.g. the source base station of the handover or a H(e)NB GW automatically or by requesting it. Thus, the MME/SGSN may be aware of the mobility of the UE and may forward this information to the GW/PCEF 2022 automatically, based on an event trigger or by a request. Hence, the information which is related to and indicates that the UE is attaching to the base station may be originated and provided by the mobility management entity, e.g. the MME/SGSN.

In scenarios of the present embodiments, mobility may cover both idle mode mobility and active mode mobility (handovers) of the UE. As soon as the MME/SGSN or another relevant element has the information of which H(e)NB or (e)NB is serving the UE, it can forward this information to the GW/PCEF 2022.

The PCRF 2021 may have established at least one relevant event trigger or policy rule in order to receive further information of mobility events of the UEs within femto, from femto to macro and/or from macro to femto base stations. The PCRF 2021 may instruct the GW/PCEF 2022 or BBERF 2028 to report the mobility events corresponding to the event trigger or policy rule by transmitting information of the event trigger to the GW/PCEF 2022 or BBERF 2028. The GW/PCEF 2022 or BBERF 2028 may be configured to report, based on this information, the information of the UE attaching to the base station to the PCRF 2021 if it detects an event corresponding to the event trigger. The event corresponding to the event trigger may be for example one of the above mentioned mobility events. In subsequent signaling from the PCRF 2021 to the GW/PCEF 2022 or BBERF 2028, e.g. in a modified acknowledgement of the IP CAN session modification, the PCRF 2021 may provide modifications on the set of the event triggers. In a case where a BBERF 2028 is used in the mobile core network, the BBERF 2028 may transmit the information indicating that the UE is attaching to the base station directly to the PCRF 2021. The BBERF 2028 may be used for example when the UE is attached to an LTE access and Proxy Mobile I P (PMIP) S5 interface is used between the S-GW and P-GW. The PCRF 2021 may instruct the BBERF 2028 to report the mobility events corresponding to the event trigger or PCC rule by transmitting information of the event trigger to the BBERF 2028. The BBERF 2028 may be configured to report, based on this information, the information indicating that the UE is attaching to the base station to the PCRF 2021 if it detects an event corresponding to the event trigger.

In step S404 of Fig. 4, the GW/PCEF 2022 may trigger the IP CAN session modification if the event defined by one of the activated event triggers or PCC Rules has been detected. In step S405, the GW/PCEF 2022 may forward the received information indicating that the UE is attaching to the base station to the PCRF 2021. In a roaming case, the information may be transmitted to the visited PCRF which acts as a proxy between the PCEF and the PCRF 2021 . This way, the PCRF 2021 becomes aware that the U E has been handed over within femto or between femto and macro base stations. The PCRF 2021 may use this information in step S409 to determine whether there are existing connections for other UEs to the base station identified in the information, as described above. If there are no existing connections for the other UEs, the PCRF 2021 may establish a policy control session specific for the base station identified in the received information on the S9a Diameter interface towards the BPCF in the fixed access network. If, based on the determining, there is already an existing connection for another UE to the base station identified in the information, the PCRF 2021 may modify or update the existing S9a session regarding the base station with information relating to the UE.

The Gx Diameter session between the GW/PCEF 2022 and PCRF 2021 or the Gxx Diameter session between the BBERF 2028 and PCRF 2021 may have been established when the UE attached via the source (first) base station of the handover. Thus, the PCRF 2021 may have the information available that the UE was connected to the source (first) base station before attaching to the target (second) base station. The PCRF 2021 may use the information of the source (first) base station in step S409 to determine whether there are other UEs connected to the source (first) base station, which may no longer serve the UE. If there are no other UEs connected to the source base „

21 station of the handover, the PCRF 2021 may release a policy control session on the S9a Diameter interface towards the BPCF 2024 for this source (first) base station.

Fig. 5 is a block diagram of an apparatus 2021 according to an embodiment of the invention. The apparatus 2021 may be a policy control and charging rules function (PCRF). It may comprise a receiver 501 , a processor 502, a transmitter 503 and a memory 504. The above units may be operatively connected via e.g. a bus 505.

Fig. 6 is a flow diagram of a method according to an embodiment of the invention, which may be performed by the apparatus according to Fig. 5. The receiver 501 may receive information of a UE attaching to a H(e)NB or (e)NB, which corresponds to step S601 of Fig. 6. The information may be received from a GW (PCEF) over a Diameter interface. In some embodiments, the information may be received at I P CAN session establishment or IP CAN session modification and included in the session establishment or modification signaling.

The processor 502 may determine whether there are already other U Es connected to the H(e)NB or (e)N B identified in the information received from a GW (PCEF) by the receiver 501 . This corresponds to step S602 in Fig. 6. The determination may be based on information received at the time of establishment of a PDN connection or PDP context and a related Gx session for the other UEs. The information of the PDN connections or PDP contexts for the other UEs may be stored in an internal or external memory 504. If the UE attaching to the H(e)NB/(e)NB identified in the received information is the first UE attaching to this H(e)NB/(e)NB and there are no connections for the other UEs, the transmitter 503 may establish a policy control connection related to the H(e)NB/(e)NB identified in the received information over S9a Diameter interface towards a policy control function in a fixed access network (step S603). If, based on the determination, there are already other UEs connected to the H(e)N B/(e)NB identified in the received information, a policy control session has already been established for this H(e)NB/(e)NB. Thus, the method will end and no new policy control sessions are established.

Alternatively, if, based on the determination, there are already other UEs connected to the H(e)NB/(e)NB identified in the received information, in some embodiments, the PCRF 2021 may modify or update the existing S9a session which was established at the base station with information relating to the UE.

Fig. 7 is a block diagram of an apparatus 2021 according to an embodiment of the invention. The apparatus 2021 may be a policy control and charging rules function (PCRF) as shown in Fig. 5. It may comprise a receiver 701 , a processor 702, a transmitter 703 and a memory 704. The above units may be operatively connected via e.g. a bus 705.

Fig. 8 is a flow diagram of a method according to an embodiment of the invention which may be performed by the apparatus according to Fig. 7. The processor 702 may be configured to detect in step S801 that the UE has been connected to a first base station before attaching to the second base station. In some embodiments, the processor 702 may detect a handover of the UE from the source (first) base station to the target (second) base station. In some embodiments, the processor 702 may perform the detection based on the information that the receiver 701 received at the time of establishment of the PDN connection / PDP context for the UE and establishment of the related Gx session. The information of the PDN connections for the UE may be stored in an internal or external memory 704. After the detection in step S801 , the processor 702 may determine whether there are other UEs connected to the source (first) base station of the handover. This corresponds to step S802 of Fig. 8. The processor 702 may be aware of this based on the information received at the time of establishment of a PDN connection / PDP context for the UEs and establishment of the related Gx session. The information of the PDN connections for the other UEs may be stored in an internal or external memory 704.

If, based on the determination (S802), there are no other UEs connected to the first base station, the transmitter 703 may release a policy control session related to the first base station in step S803. The policy control session may be an S9a Diameter session towards the BPCF in a fixed access network. If there are other UEs connected to the first base station, the method ends and the existing policy control session is kept active for the other UEs.

Fig. 9 is a block diagram of an apparatus 2022 according to an embodiment of the invention. The apparatus may comprise at least one of a Policy and Charging

Enforcement Function (PCEF), a Packet Data Network Gateway (PDN GW) and a Bearer Binding and Event Reporting Function (BBERF). The apparatus 2022 may comprise a receiver 901 , a processor 902, a transmitter 903 and a memory 904. The above units may be operatively connected via e.g. a bus 905.

Fig. 10 is a flow diagram of a method according to an embodiment of the invention, which may be performed by the apparatus according to Fig. 9. The receiver 901 may receive information of an event trigger or a policy rule from a PCRF for reporting events related to mobility of a UE. This corresponds to step S1001 of Fig. 10. The event trigger or policy rule may be established by the PCRF and it may comprise for example a trigger for one or more of the following events:

- UE moves within femto base stations;

- UE moves from a femto to a macro base station; and

- UE moves from a macro to a femto base station.

In some embodiments, the apparatus 2022 according to Fig. 9 may also request information of the above mobility events from the MME/SGSN according to the information of the event trigger. The apparatus 2022 may also receive a request from a PCRF to transmit information of the above mobility events to the PCRF.

According to an embodiment, the receiver 901 may further receive information related to and indicating that a UE is attaching to a base station (step S1002 of Fig. 10). The information may be received from the MME or SGSN. In some embodiments, the information may also comprise information of a handover of the U E from a first base station to a second base station, as a result of which the UE is attaching to the second base station. The information may comprise for example information that corresponds to the event trigger. It may for example comprise an indication that the UE has moved within femto base stations, from a femto to a macro or from a macro to a femto base station.

The processor 902 may use the event trigger information received in step S1001 to detect events as defined in the event trigger information. If the processor 902 detects an event corresponding to the event trigger information, it may cause the transmitter 903 to report the event to the PCRF. For example, the processor 902 may determine in step S1003 of Fig. 10 that the information indicating that the UE is attaching to the base station corresponds to the event trigger defined in the event trigger information. Thus, based on the determination (S1003), the processor 902 may cause the transmitter 903 to transmit the information indicating that the UE is attaching to the base station to the PCRF. The transmission may happen on Gx interface for example in a modified IP CAN session modification signaling.

Fig. 1 1 is a block diagram of an apparatus 2023 according to an embodiment of the present invention. The apparatus 2023 may perform a method as shown in a flow diagram in Fig. 12. The apparatus 2023 may be a MME or SGSN. In this embodiment, the apparatus 2023 may hold information of mobility of UEs and provide it to a gateway by a request, automatically or based on an event trigger. The apparatus 2023 may receive the information of mobility of UEs from e.g. the source H(e)NB 2025 of a handover or a H(e)NB GW automatically or by requesting it. According to an embodiment, first, a receiver 1 101 of the apparatus 2023 may receive a request requesting information of events related to mobility of U Es (step S1201 of Fig. 12). In some embodiments, the request may comprise a request for information of events related to attachment of UEs to a base station. The events may be defined in event trigger information provided by the PCRF 2021 .

According to an embodiment of the invention, as a response to the request received from the GW/PCEF 2022 or a BBERF 2028 by the receiver 1 101 , the transmitter 1 103 may transmit the information of the mobility of the UEs to the gateway (GW/PCEF 2022 or BBERF 2028). According to an embodiment, the transmitter 1 103 may transmit information indicating that a UE is attaching to a second base station connected to a fixed broadband access network. The base station may be a 3GPP femto or pico base station or a macro network base station. In some embodiments, the transmitter 1 103 may transmit information indicating that a UE is attaching to the second base station from a first base station after a handover.

Although described above mainly with respect to methods, procedures, and apparatuses, it is to be understood that the present invention also covers a computer program products for implementing such methods or procedures and/or for operating such apparatuses, as well as computer-readable (storage) media for storing such computer program products.

It should be also understood that the mentioned method steps can be realized in individual functional blocks or by individual devices, or one or more of the method steps can be realized in a single functional system or by a single device. Method steps and/or devices, means and units likely to be implemented as hardware components at one of the entities are hardware independent and can be implemented using any known or future developed hardware technology or any hybrids of these, such as MOS, CMOS, BiCMOS, ECL, TTL, etc, using for example ASIC components or DSP components, as an example. Generally, any method step is suitable to be implemented as software or by hardware without changing the idea of the present invention. In this context, "first" and "second", etc. in relation to devices or network devices or interfaces or security data may not be understood as hierarchy, it should be understood only to distinguish different devices or interfaces from each other.

Claims

1. A method for establishing a policy control session, comprising

receiving (S303, S601 ), from a gateway (2022), information indicating that a user equipment (UE) (203) of a user of a mobile network (200) is attaching to a second base station (2026) connected to a fixed broadband access network (202);

determining (S602), based on the received information indicating that the UE (203) is attaching to the second base station (2026), whether there is at least one packet data connection between at least one other UE and the second base station (2026); and

establishing (S307, S603) a policy control session related to the second base station (2026), with a policy control function (2024) of the fixed broadband access network (202) if there are no packet data connections between the at least one other U E and the second base station (2026).

2. The method of claim 1 , further comprising

detecting (S405, S801), by a policy control function (2021 ) of the mobile network (200), a handover of the U E (203) from a first base station (2025) to the second base station (2026);

determining (S802), by the policy control function (2021) of the mobile network (200), whether there is at least one packet data connection between at least one other UE and the first base station (2025); and

releasing (S409, S803) a policy control session related to the first base station (2025), from the policy control function (2024) of the fixed broadband access network

(202) if there are no packet data connections between the at least one other UE and the first base station (2025).

3. The method of claim 1 or 2, further comprising

establishing an event trigger for reporting at least one event related to mobility of UEs; and

transmitting (S310) information of the event trigger to the gateway (2022).

4. The method of any of preceding claims, wherein the information indicating that the UE

(203) is attaching to the second base station (2026) comprises one of a base station identifier, a cell identifier and a service area identifier of the second base station (2026).

5. The method of any of preceding claims, wherein the information indicating that the UE (203) is attaching to the second base station (2026) comprises one of an indication that the UE (203) is attaching to a femto base station and an indication that the U E is attaching to a macro network base station.

6. The method of any of preceding claims, wherein the information indicating that the UE (203) is attaching to the second base station (2026) is received via one of a Gx interface, a Gxc interface and a Gxx interface of 3GPP mobile core network.

7. The method of any of preceding claims, wherein the receiving (S303) of the information indicating that the UE (203) is attaching to the second base station (2026) comprises receiving at establishment of a Packet Data Network (PDN) connection for the UE (203).

8. The method of any of preceding claims, wherein the policy control session is established over an S9a interface between policy control entities of the mobile network (200) and the fixed broadband access network (202).

9. The method of claim 3, wherein the information of the event trigger is used to configure the gateway (2022) to transmit the information indicating that the UE (203) is attaching to the second base station (2026), to the policy control function (2021 ) of the mobile network (200), if an event corresponding to the information of the event trigger is detected.

10. A method, comprising

receiving (S310, S1001) information of an event trigger for reporting at least one event related to mobility of user equipment (UE);

receiving (S1002), from a mobility management entity (2023), information indicating that a UE (203) of a user of a mobile network (200) is attaching to a second base station (2026) connected to a fixed broadband access network (202);

determining (S1003) that the information indicating that the UE (203) of the user of the mobile network (200) is attaching to the second base station (2026) corresponds to the information of the event trigger; and

transmitting (S405, S1004) the information indicating that the UE (203) is attaching to the second base station (2026) to a policy control function (2021 ) of the mobile network (200).

1 1. The method of claim 10, further comprising transmitting to the policy control function (2021 ) of the mobile network (200) information of a handover of the UE (203) from a first base station (2025) to the second base station (2026).

12. The method of claim 10 or 1 1 , wherein the information indicating that the UE (203) is attaching to the second base station (2026) comprises one of a base station identifier, a cell identifier and a service area identifier of the second base station (2026).

13. The method of any of claims 10 to 12, wherein the information indicating that the UE (203) is attaching to the second base station (2026) is transmitted to the policy control function (2021 ) of a mobile network (200) via one of a Gx interface, a Gxc interface and a Gxx interface.

14. The method of any of claims 10 to 13, wherein the receiving (S1002) and the transmitting (S405) of the information indicating that the UE (203) is attaching to the second base station (2026) is performed at establishment of a Packet Data Network (PDN) connection for the UE (203).

15. The method of any of claims 10 to 14, further comprising configuring, based on the information of the event trigger, transmission of the information indicating that the UE (203) is attaching to the second base station (2026), to the policy control function (2021 ) of the mobile network (200), if an event corresponding to the event trigger is detected.

16. The method of any of claims 10 to 15, further comprising sending a request to the mobility management entity (2023), requesting information of the mobility events as defined in the information of the event trigger.

17. A method, comprising

receiving (S1201 ), from a gateway (2022), a request requesting information of events related to mobility of user equipment (UE) as defined in an event trigger provided by a policy control function (2021 ) of a mobile network (200);

transmitting (S1202), to the gateway (2022), information indicating that a U E (203) is attaching to a second base station (2026) connected to a fixed broadband network (202), as a response of receiving the request.

18. The method of claim 17, further comprising transmitting to the gateway (2022) information of a handover of the UE (203) from a first base station (2025) to the second base station (2026).

19. The method of claims 17 or 18, wherein the information indicating that the UE is attaching to the second base station (2026) comprises one of a base station identifier, a cell identifier and a service area identifier of the second base station (2026).

20. The method of any of claims 17 to 19, wherein the transmitting is performed at establishment of a Packet Data Network (PDN) connection for the UE (203).

21. An apparatus (2021 ), comprising a receiver (501 ) configured to receive (S303), from a gateway (2022), information indicating that a user equipment (UE) (203) of a user of a mobile network (200) is attaching to a second base station (2026) connected to a fixed broadband access network

(202) ;

a processor (502) configured to determine based on the received information indicating that the UE (203) is attaching to the second base station (2026), whether there is at least one packet data connection between at least one other UE and the second base station (2026); and

a transmitter (503) configured to establish (S307) a policy control session related to the second base station (2026), with a policy control function (2024) of the fixed broadband access network (202) if there are no packet data connections between the at least one other UE and the second base station (2026).

22. The apparatus of claim 21 , wherein

the processor (502) is further configured to detect (S405) a handover of the UE

(203) from a first base station (2025) to the second base station (2026);

the processor (502) is further configured to determine whether there is at least one packet data connection between at least one other UE and the first base station (2025); and

the transmitter (503) is further configured to release (S409) a policy control session related to the first base station (2025), from the policy control function (2024) of the fixed broadband access network (202) if there are no packet data connections between the at least one other UE and the first base station (2025).

23. The apparatus of claim 21 or 22, wherein

the processor (502) is further configured to establish an event trigger for reporting at least one event related to mobility of UEs; and

the transmitter (503) is further configured to transmit (S310) information of the event trigger to the gateway (2022).

24. The apparatus of any of claims 21 to 23, wherein the information indicating that the UE (203) is attaching to the second base station (2026) comprises one of a base station identifier, a cell identifier and a service area identifier of the second base station (2026).

25. The apparatus of claim 23, wherein the information of the event trigger is used to configure the gateway to transmit the information indicating that the UE (203) is attaching to the second base station (2026), to the policy control function (2021 ) of the mobile network (200), if an event corresponding to the information of the event trigger is detected.

26. An apparatus (2022), comprising

a receiver (901 ) configured to receive (S310) information of an event trigger for reporting at least one event related to mobility of user equipment (UE);

the receiver (901 ) being further configured to receive, from a mobility management entity (2023), information indicating that a UE (203) of a user of a mobile network (200) is attaching to a second base station (2026) connected to a fixed broadband access network (202);

a processor (902) configured to determine that the information indicating that the UE (203) of the user of the mobile network (200) is attaching to a second base station (2026) corresponds to the information of the event trigger; and

a transmitter (903) configured to transmit (S405) the information indicating that the UE (203) is attaching to the second base station (2026), to a policy control function (2021 ) of the mobile network (200).

27. The apparatus of claim 26, wherein the transmitter (903) is further configured to transmit to the policy control function (2021) of the mobile network (200) information of a handover of the UE (203) from a first base station (2025) to the second base station (2026).

28. The apparatus of claim 26 or 27, wherein the information indicating that the UE is attaching to the second base station (2026) comprises one of a base station identifier, a cell identifier and a service area identifier of the second base station (2026).

29. The apparatus of any of claims 26 to 28, wherein the apparatus is configured to transmit, based on the information of the event trigger, the information indicating that the UE (203) is attaching to the second base station (2026), to the policy control function (2021 ) of the mobile network (200), if an event corresponding to the information of the event trigger is detected.

30. The apparatus of any of claims 26 to 29, wherein the apparatus is configured to send a request to the mobility management entity (2023), requesting information of the mobility events as defined in the information of the event trigger.

31. An apparatus, comprising

a receiver (1 101) configured to receive, from a gateway (2022), a request requesting information of events related to mobility of user equipment (UE) as defined in information of an event trigger provided by a policy control function (2021) of a mobile network (200); a transmitter (1 102) configured to transmit, to the gateway (2022), information indicating that a UE (203) is attaching to a second base station (2026), as a response of receiving the request.

32. The apparatus of claim 31 , wherein the transmitter (1 102) is further configured to transmit to the gateway (2022) information of a handover of the UE (203) from a first base station (2025) to the second base station (2026).

33. The apparatus of claim 31 or 32, wherein the transmitter (1 102) is configured to transmit the information indicating that the UE (203) is attaching to the second base station (2026) at establishment of a Packet Data Network (PDN) connection for the UE (203).

34. A system, comprising

a policy control function (2021) in a mobile network (200);

a gateway (2022) in the mobile network (200);

a mobility management entity (2023) in the mobile network (200); and

a policy control function (2024) in a fixed broadband access network (202);

a Diameter interface between the gateway (2022) and the policy control function (2021 ) in the mobile network (200);

a Diameter interface between the policy control function (2021 ) in the mobile network (200) and the policy control function (2024) in the fixed broadband access network (202);

wherein the Diameter interface between the gateway (2022) and the policy control function (2021 ) in the mobile network (200) supports transfer of information of a handover of a user equipment (UE) (203) from a first base station (2025) to a second base station (2026);

wherein the policy control function (2021) in the mobile network (200) is configured to

determine whether there are packet data connections between at least one other

UE and the second base station (2026) and between at least one other UE and the first base station (2025); and

establish a policy control session on the Diameter interface between the policy control function (2021) in the mobile network (200) and the policy control function (2024) in the fixed broadband access network (202) related to the second base station (2026), if there are no packet data connections between the at least one other UE and the second base station (2026); and

release a policy control session on the Diameter interface between the policy control function (2021) in the mobile network (200) and the policy control function (2024) in the fixed broadband access network (202) related to the first base station (2025), if there are no packet data connections between the at least one other UE and the first base station (2025).

35. A computer program product comprising code means to perform steps of any of claims 1 to 20 when run on a processor.