WO2016029961A1

WO2016029961A1 - Neighbouring wireless local area network access points to cellular radio access nodes

Info

Publication number: WO2016029961A1
Application number: PCT/EP2014/068371
Authority: WO
Inventors: Hans Thomas Hoehne; Daniela Laselva; Subramanya CHANDRASHEKAR
Original assignee: Nokia Solutions And Networks Oy
Priority date: 2014-08-29
Filing date: 2014-08-29
Publication date: 2016-03-03

Abstract

Neighbouring wireless local area network access points to cellular radio access nodes are determined. A wireless local area network access point serving UE connected to a cellular radio access node is determined as a neighbouring wireless local area network access point to the cellular radio access node. Information identifying the neighbouring wireless local area network access point is sent to the cellular radio access node and to a wireless local area network.

Description

NEIGHBOURING WIRELESS LOCAL AREA NETWORK ACCESS POINTS TO CELLULAR RADIO ACCESS NODES

FIELD

The invention relates generally to mobile communications networks having cellular radio access nodes and wireless local area network access points for serving user equipment.

BACKGROUND

User equipment (UE) may connect to a mobile communications network via base station(s). A base station offers radio access to the network via its coverage area. The coverage area is referred to as a cell, thereby the base stations provide cellular radio access to the network. The cellular radio access is provided typically on licensed frequency bands. Accordingly, UE capable of operating in the mobile communications network has a radio transceiver capable of operating according to a cellular radio access technology. Examples of the cellular radio access technologies include communications standards defined by the 3^rd Generation Partnership Project including Global System for Mobile Communications (GSM), Long Term Evolution (LTE), or LTE-Advanced (LTE-A).

Many present UE have capabilities to communicate using two or more radio access technologies. In addition to connecting to a mobile communications network on over a cellular radio access technology, the UE may be capable of connecting to a Wireless Local Area Network (WLAN) by a transceiver capable of communicating according to a radio access technology defined by the IEEE 802.1 1 family of standards. In WLANs, UE connects to a WLAN Access Point (WLAN-AP) that offers radio coverage in the WLAN.

Deployment of WLAN-APs into mobile communication networks may be used to increase network capacity. Traffic from the cells may be offloaded to the WLAN-APs. However, the WLAN-APs may not be within the coverage areas of the cells, whereby offloading traffic from the cells to the WLAN-APs may not be possible and result in failures of the offloaded connections. This affects particularly the quality of service experienced by the UE.

On the other hand the network operator is interested in the amount of traffic served by the network including the WLAN-APS and cells. WLAN- APS may be deployed into locations in the network, where their utilization may be low and/or the WLAN-APs cannot accept offloaded traffic from the cells.

BRIEF DESCRIPTION

Embodiments of the invention include methods, apparatuses and computer program products characterized by what is stated in the independent claims.

Some embodiments provide a solution that enables identifying neighbouring wireless local area network access points to base stations. In future mobile communications networks, e.g. the 5^th generation of mobile communicaitons networks, identifying the neighbouring WLAN-APs to base stations e.g. eNBs or access points, is foreseen to be increasingly significant due to the WLANs becoming an integral part of the future networks.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be described in greater detail by means of embodiments with reference to the attached drawings, in which

Figure 1 presents an example of a mobile communications network according to an embodiment;

Figure 2a illustrates delivery of information regarding neighboring wireless local area network access points to a cellular radio access node;

Figure 2b illustrates a method of delivering information regarding neighboring wireless local area network access points to a wireless local area network;

Figure 3 illustrates a method of delivering information regarding neighboring wireless local area network access points to a wireless local area network as part of an authentication procedure;

Figure 4 illustrates a method of obtaining information regarding neighboring wireless local area network access points to a cellular radio access node;

Figure 5 illustrates communications in a mobile communications network according to an embodiment;

Figure 6 illustrates updating information of neighboring wireless local area network access points, when the serving wireless local area network access point is changed;

Figure 7 illustrates updating information of neighboring wireless lo- cal area network access points, when the serving cellular radio access node is changed; and

Figure 8 illustrates an apparatus according to an embodiment.

DESCRIPTON OF EMBODIMENTS

The following embodiments are exemplary. Although the specifica- tion may refer to "an", "one", or "some" embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment(s), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments.

Figure 1 presents an example of a mobile communications network according to an embodiment. The mobile communications network include a radio access network 102 that connects to UE 104 over a wireless connection, a core network 106 that performs subscription and mobility management of the UE. The radio access network and the core network connect the UE to exter- nal networks 126, e.g. the Internet. The core network maintains location information of the UE, whereby traffic may be routed by the core network to and/or from the UE. In this way the UE may communicate traffic between devices located in the same mobile communications network or devices located in the external networks.

The radio access network of the mobile communications network may comprise a cellular radio access network 109 that includes one or more cellular radio access nodes 1 10, and a WLAN 1 1 1 that includes one or more WLAN-APs 1 12. The WLAN may be according to the IEEE 802.1 1 family of standards. The cellular radio access nodes and WLAN-APs connect to UE over wireless radio frequency connections. Depending on implementation, the cellular radio access network and/or the WLAN may include a controller node 1 13. In the example of Figure 1 , the WLAN includes a WLAN Access Controller (WLAN AC). In the WLAN, the WLAN AC may be a WLAN-AP via which the other cellular WLAN-APs connect to the core network.

In the cellular radio access network the controller (not shown) may be a cellular radio access node via which the other cellular radio access nodes connect to the core network. In another example, the controller may be a dedicated controller, for example a Radio Network Controller, when the cellular radio access network is a Universal Mobile Telecommunications network de- fined by the 3GPP. The cellular radio access nodes transmit and received radio frequency signals in coverage areas referred to cells. A cell has allocated resources for communications with the UE. The resources of the cell may include a radio frequency band, a transmission power, one or more antennas, and in- formation of neighboring cells and/or WLAN APs. The resources of the cell are defined by the mobile communications network. The resources of the cell may be defined for example via an operations and management connection to the cellular radio access node hosting the cell. In this way the cell may be defined an operational licensed to the operator of the mobile communications network. The cellular radio access nodes may be base stations, Node-Bs or evolved- NBs depending on the implementation.

A neighboring WLAN-AP or cell to a cellular radio access node may have at least partly overlapping coverage are with the cellular radio access node, whereby the UE may be served by the WLAN-AP and the cellular radio access node simultaneously.

The WLAN-APs transmit and receive radio frequency signals in coverage areas referred to as basic service areas (BSAa). A BSA is formed by a single WLAN-AP and its coverage area of radio frequency transmissions.

A WLAN-AP operates on a radio frequency band that is typically in the range of 2.4 GHz or 5 GHz. The operating frequency bands of WLAN-APs are typically unlicensed frequency bands, for example frequency bands reserved for Industrial Scientific and Medical (ISM) use.

UE 104 may connect to the mobile communications network via a WLAN-AP or a cellular radio access node, when the UE is within their respec- tive coverage areas. When the UE is located within the coverage areas of both the cellular radio access node and the WLAN-AP, the UE may connect to both of the cellular radio access node and the WLAN-AP. When the UE is connected to the cellular radio access node it may be identified in the cellular radio access network by user equipment identifier, UE_ID. In the cellular radio ac- cess network, the UE_ID may be a Cellular Radio Network Temporary Identifier (C-RNTI), for example. This means that the location of the UE is known to the core network and traffic may be routed between the core network and the UE. The location may be known. The location maybe known in the level of a group of cellular radio access nodes via which the UE may be reached, or the location maybe known in the level of the cellular access node that is serving the UE. When the UE is connected to the WLAN-AP, the UE may be identified in the WLAN and traffic from the UE may be routed between the WLAN and the core network of the mobile communications network. The location of the UE within the WLAN is conventionally not known, while the traffic to and/or from the UE may be served by the WLAN. In the WLAN, the UE may be identi- fied by a Medium Access Control (MAC) address of the UE, i.e. WLANJJEJD. The WLANJJEJD identifies the UE only within the WLAN and outside the WLAN in the mobile communications network the UE_ID, e.g. the C-RNTI may be used to identify the UE.

The core network may follow the core network architecture of the System Architecture Evolution (SAE) defined in the LTE. The SAE has a flat, all-Internet Protocol (IP) architecture with separation of control plane and user plane traffic. The SAE core network entities include a Mobility Management Entity 1 14 (MME), a Serving Gateway 1 16 (S-GW), a Packet Data Network Gateway 1 18 (P-GW), an authentication agent 120 (AAA), a Home Subscrip- tion Server 122 (HSS), a WLAN Access Gateway 124 (WAG). The HSS is a central database that contains user-related and subscription-related information. The functions of the HSS include functionalities such as mobility management, call and session establishment support, UE authentication and UE access authorization. The MME is the key control-node for the radio access network. It is responsible for authenticating the UE, by interacting with the HSS. The MME is also responsible for generation and allocation of temporary identities to UEs. In LTE, the temporary identifier is referred to as a Global Unique Temporary Identifier (GUTI) and which is used to refer to a specific UE instead of the International Mobile Subscriber Identity (IMSI) that is a unique identifier used in cellular communications networks to identify a user. The GUTI identifies the UE in mobile communications networks globally. The MME may maintain a mapping between IMSI and GUTI.

The S-GW routes and forwards user data packets and manages and stores UE contexts. The PDN Gateway provides connectivity from the UE to external packet data networks by being the point of exit and entry of traffic for the UE. The WAG connects the WLAN access network securely to the CN. The AAA performs authentication, authorization and accounting.

Connections between the entities in the mobile communications network may be implemented by interfaces defined by standards, e.g. the LTE standards. The mobile communications network may include further entities that are not illustrated in Figure 1 . The further entities may include for example cellular radio access nodes that may connect to the CN as described above. The further entities, e.g. the cellular radio access nodes may be also connected to each other for communications of information, e.g. user plane data or control plane data and/or messages.

It should be appreciated that the SAE architecture is only an example and the number of core network, their names, entities and tasks carried out by the entities may vary depending on the standard the communications standard the mobile communications network conforms to.

Example embodiments will now be described with reference to Fig- ure 5 illustrating communications in a mobile communications network according to an embodiment. An example of the mobile communications network is illustrated in Figure 1 . In Figure 5, entities of the mobile communications network may be the entities of the mobile communications network in Figure 1 . The entities may perform methods illustrated in Figures 2a, 2b, 3 and 4, which are reference in the following together with Figure 5.

Referring to the architecture of Figure 1 , the methods of Figures 2a and 2b may be performed by the S-GW or P-GW or MME, the method of Figure 3 may be performed by the AAA (in Figure 3 the P-GW may be replaced also with the MME) and the method of Figure 4 may be performed by the cellu- lar radio access node and optionally also by MME or P-GW The S-GW and P- GW may be implemented in a single entity, S-GW/P-GW, where the functionalities of the S-GW and P-GW are combined. It should be appreciated that since both the MME and the P-GW or S-GW/P-GW, are aware of the attachment of the UE to a specific eNB, the functionalities described in the following referring to the S-GW/P-GW, P-GW or AAA may be performed also in the MME.

The communications between entities of the mobile communications network illustrated in Figure 5 may start 202, 302, 402, when the mobile communications network is deployed and the entities are operational. This means that the mobile communications network can connect to the UE 104 and serve traffic of the UE. Accordingly, the UE can access the services of the mobile communications network. The UE may have a subscription to enable access to the services of the mobile communications network. The subscription may be provided by an operator of the mobile communications network. The mobile communications network may identify that the UE attempting to connect to the mobile communications network has a valid subscription by authenticating the UE. The authentication may comprise identifying the UE and checking the subscriber database for the subscription of the UE and services offered by the subscription.

The S-GW/P-GW/MME 1 16/1 18 may maintain 203 information identifying cellular radio access nodes registered for receiving information regard- ing neighboring wireless local area network access points, in the mobile communications network. The information identifying a cellular radio access node may be an identifier of the cellular radio access node. The mobile communications network may comprise a cellular radio access network 109 and a wireless local area network 1 1 1 , as illustrated in Figure 1 . The maintaining may com- prise registering cellular radio access nodes and delivering the information identifying cellular radio access nodes registered to the registered cellular radio access nodes. The registration and delivery of the information regarding neighboring wireless local area network access points may be provided as a service referred to as Automatic Neighbor Relations (ANR). The ANR will be used from in the following to describe a service to one or more cellular radio access nodes. The cellular radio access nodes that are registered to ANR receive information regarding the neighboring WLAN-APs. Accordingly, the S- GW/P-GW may receive registration messages 502 from those cellular radio access nodes that request to receive the information regarding the neighboring WLAN-APs. It is possible that the P-GW may be also the MME.

The cellular radio access node may store 404 information identifying neighboring WLAN-APs to the cellular radio access node. The information identifying a neighboring WLAN-AP may be an identifier of the WLAN_AP, WLAN-APJD, and comprise a MAC address, for example. It should be appre- ciated that at the beginning, after the cellular radio access node has just registered to the ANR service, there may be zero neighboring WLAN-APs to the cellular radio access node. After the ANR delivers 406, 514 the information identifying neighboring WLAN-APs to the cellular radio access node, the cellular radio access node may store the information, e.g. WLAN-APJDs. The number of neighboring WLAN-APJDs stored to the cellular radio access node may be limited only by practical considerations of implementation.

During operation of the mobile communications network, the UE may connect 504 to the mobile communications network over the radio interface to one or more cellular radio access nodes. Accordingly, the UE may be served 504 by the cellular radio access nodes. Typically, the UE served by the cellular radio access node may be referred to be in a CONNECTED state. The cellular radio access nodes connect 506 the UE to the core network of the mobile communications network and to the core network entities, e.g. the S- GW/P-GW and/or the MME.

The UE may send an authentication request 508a over the radio in- terface to the WLAN-AP. The WLAN-AP delivers the authentication request 508b to the AAA. Accordingly, the AAA may obtain 302 the authentication request 508b for the UE to the mobile communications network via a wireless local area network access point serving the UE. The authentication request received by the AAA may include information identifying the WLAN-AP and the user equipment that requests authentication to the mobile communications network.

During WLAN authentication, the UE (or station (STA) in WLAN terminology) contacts the AP. The AP will act as an authenticator from the perspective of the most commonly used authentication protocol RADIUS. The au- thenticator will communicate with the RADIUS server, the AAA. Different types of authentication exist. Hotspot2.0 (HS2.0) authentication usually involves at least initially the UE's 3gpp identity, i.e. the International Mobile Subscriber Identity (IMSI). In particular, with HS2.0 an identity based on Extensible- Authentication-Protocol-Method-for-GSM-Subscriber-ldentity-Module / Authen- tication-and-Key-Agreement / Authentication-and-Key-Agreement-Prime (EAP- SIM/AKAAKA-Prime) may be used. Authentication in WLAN thus allows matching the WLAN identity of the UE with the 3GPP identity of the UE. Later re-authentications may use other identifiers. For background information we note that HS2.0 provides WLAN extensions to the RADIUS protocol which al- low advanced authentication procedures from the perspective of the AP, such as preventing UE to attempt connecting to an AP for a certain amount of time. The authentication and prevention of the authentication can happen in stages: First the UE will associate to the WLAN-AP at the MAC level. Then the WLAN- AP will communicate with the UE to obtain its credentials. The UE may be blocked for example solely on grounds of their MAC address. When the WLAN-AP has obtained authentication from the AAA, the UE may be connected to the mobile communications for access to services provided by the mobile communications network.

The UE may send the authentication as an attempt to connect to the mobile communications network via the WLAN-AP. The attempt may be performed following that the UE determines that it is located within the coverage area of the WLAN-AP. Additionally to the location of the UE being within the coverage area of the WLAN-AP, the UE may attempt to connect to a WLAN for preference of using a WLAN connection for one or more criteria including but not limited to: an amount of data to be transferred over the radio interface, subscription settings, etc. Accordingly, UE served by a cellular radio access node may connect to the WLAN based on the location of the UE and/or one or more criteria used for selecting a radio interface, e.g. WLAN or cellular, to be used.

The UE may be identified in the WLAN, for example by the MAC address of the UE. The UE identifier in the WLAN will be referred to as WLAN_UE_ID. Accordingly, the information identifying the UE obtained from the WLAN-AP may be the WLANJJEJD, whereby the AAA will obtain at initial authentication an identifier of the UE (UE_ID) outside the WLAN. The identifier of the UE outside the WLAN may be the 3GPP ID of the UE, for example the IMSI. The AAA may obtain other identifiers of the UE (UEJD) outside the WLAN, in the mobile communications network, e.g. by querying the HSS or the MME. While the IMSI is known to AAA and HSS, for security reasons it is not advised to use it in other network elements. Therefore one commonly used UE identifier in 3GPP networks is the GUTI. The MME and eNB use the GUTI, and the AAA and HSS can be made aware of it when needed. The MME is also aware of mapping of IMSI to GUTI. The UEJD may be obtained from the MME that identifies the UE based on the authentication request.

After receiving the authentication request 508b, the AAA may perform authentication 304 of the UE identified in the authentication request. The AAA may be caused to send 306, 510 the information identifying the wireless local area network access point and information identifying the UE in the cellular radio access network to the S-GW/P-GW/MME. The AAA may query the HSS or the MME to obtain the GUTI before talking to the S-GW/P-GW or the MME. The information may be sent from the AAA as a query to obtain infor- mation to the AAA whether the UE attempting to connect via the WLAN-AP is served by a cellular radio access node and information identifying the serving cellular radio access node. In this way it may be obtained information for confirming that the UE is served by the WLAN-AP and a cellular radio access node simultaneously. When the UE is served simultaneously by the WLAN-AP and the cellular radio access node, it may be determined that their coverage area areas are at least partly overlapping and the WLAN-AP is neighboring to the cellular radio access node.

The S-GW/P-GW or MME may obtain 204 the information sent 510 from the AAA. The S-GW/P-GW may determine 206, 512 the WLAN-AP serv- ing the UE as a neighboring WLAN-AP to the cellular radio access node serving the user equipment. The determining may be performed on the basis of matching the information identifying the WLAN-AP and the UE, e.g. matching the WLAN-AP identifier and the UE_ID, received from the AAA with the information of cellular radio access nodes registered to the ANR, and determining that the UE is currently served (in CONNECTED state) with a cellular radio access node. If the UE is known to the MME but in idle mode, no ANR relation will be recorded.

The S-GW/P-GW or MME may be caused to send 208, 514 information identifying the WLAN-AP serving the user equipment to the cellular ra- dio access node serving the user equipment, when the cellular radio access node serving the user equipment is registered to the ANR. The sent information may include the information identifying the UE, e.g. UE_ID.

After the S-GW/P-GW has sent 208, 514 the information identifying the WLAN-AP serving the user equipment to the cellular radio access node serving the user equipment, when the cellular radio access node serving the user equipment is registered to the ANR, the cellular radio access node knows at least one neighboring WLAN-AP and the method performed by the S-GW/P- GW may end 209.

In the cellular access node, the information identifying the WLAN- AP, e.g. the WLAN-APJD, obtained 406, 514 from the S-GW/P-GW, may be stored 410 as a neighboring WLAN-AP to the cellular radio access node, when 408 the user equipment is served by the cellular radio access node. The cellular radio access node may determine 516 whether the UE served by the WLAN-AP is also served by the cellular radio access node. When the UE is served by the cellular radio access node, the UE may be in a CONNECTED state. The determining may be performed on the basis of the UE_ID obtained 514 from the S-GW/P-GW. If the UE is determined 408 to be served by the cellular radio access node, the WLAN-AP maybe determined as a neighboring WLAN-AP to the cellular radio access node and stored 410. In this way the cellular radio access node may obtain information of neighboring WLAN-APs to be used for offloading traffic from the cellular radio access node to the WLAN-AP and/or for on-loading traffic from the WLAN-AP to the cellular radio access node. In offloading traffic from the cellular radio access node, traffic of the UE is steered from the cellular radio access node to be served by the WLAN-AP. In on-loading traffic from the WLAN-AP, traffic of the UE is steered from the WLAN-AP to the cellular radio access node serving the UE. Particularly WLAN-APs that serve UE also served by the cellular radio access node may be considered to have at least partly overlapping coverage areas and may be used for purposes of serving traffic of the same UE. After the cellular radio access node has obtained information identifying at least one neighboring WLAN-AP, the process may end 412. If the UE is not served 408 by the cellular radio access node, the WLAN-AP is not stored as neighboring to the cellular radio access node and the method ends in 412. When the UE is not served by the cellular radio access node, the UE may be in an Idle state.

Figure 2b illustrates delivering information regarding one or more neighboring WLAN-APs to the WLAN. The method may start 212 after the WLAN-AP serving the UE is determined 512 as a neighboring WLAN-AP to the cellular radio access node serving the user equipment. In 214, it may be determined, whether there are any ongoing and/or incomplete core network procedures towards the WLAN. In the WLAN the entity participating in the proce- dure as en endpoint may be a WLAN-AP or AC. The core network procedures may comprise signaling between the core network and the WLAN. The signaling may be related to service provided by the mobile communications network to the UE connected to the WLAN via the serving WLAN-AP. An incomplete procedure may be a procedure that is started by a request from the WLAN to the CN or vice versa. The procedure may be completed by a response back to the originator of the request. In one example, the CN procedure comprises an authentication procedure of the UE. The entities carrying out the procedure in the WLAN and the CN may any of the entities in WLAN and CN in Figure 1 .

The method proceeds to 218, if 216 there are no incomplete CN procedures between the CN and the WLAN. Then, in 218 the information regarding the neighboring WLAN-AP is caused to be sent 518 to the WLAN from the S-GW/P-GW. On the other hand, if there is one or more incomplete CN procedure, the method proceeds to 220, where the information regarding the neighboring WLAN-AP is caused to be sent to the CN entity that is participat- ing in the procedure as an endpoint. In the example of Figure 5, the AAA is participating in the authentication procedure that is carried out between the AAA and the WLAN. The CN entity may then deliver 218, 524 the information regarding the neighboring WLAN-AP as a part of the CN procedure, e.g. the authentication procedure. The method ends in 222 after the delivery route either as a part of an active CN procedure or directly has been determined for the neighboring WLAN-AP information.

The AAA may obtain 308, 522, in response to the information sent 306, 510 to the S-GW/P-GW, information identifying the cellular radio access node serving the UE and registered for the ANR. The information may be obtained by the AAA, after the WLAN-AP serving the UE is determined 206, 512 as a neighboring WLAN-AP to the cellular radio access node and the authentication procedure is still incomplete between the UE connected to the WLAN and the AAA. The AAA may be caused to send 524 the information identifying the cellular radio access node serving the UE and registered for the ANR, and information identifying the WLAN-AP serving the UE to the WLAN as part of an authentication procedure. Preferably the information is delivered from the AAA to the WLAN in a signaling message of the authentication procedure. After the signaling messages the authentication procedure may be completed. In this way the signaling messages of the authentication procedure may be utilized in delivering the information regarding the neighboring WLAN-APs and cellular radio access nodes. The method performed by the AAA ends 310 after the WLAN is delivered the information regarding the neighboring WLAN-APs and cellular radio access nodes.

In the WLAN, the information regarding the neighboring WLAN-APs and cellular radio access nodes obtained from the CN, e.g. the S-GW/P-GW as described in the method Figure 2b, or the AAA as described in the Figure 3, may be stored 526 to the WLAN-AP or the AC. Since the WLAN has information of the neighboring WLAN-APs to cellular radio access nodes, various traffic monitoring tasks and/or traffic steering tasks may be performed. In one example, the WLAN may perform UE_ID matching to traffic from the UE and send information of traffic from a specific UE connected to the WLAN via a WLAN-AP, to the cellular radio access node that the WLAN-AP is neighboring.

Figure 6 illustrates updating information of neighboring WLAN-APs, when the serving WLAN-AP is changed. The updating takes place between entities of the mobile communications network. Examples of the entities are illustrated in Figure 1 . In Figure 5, UE 104 is served 604 by a cellular radio access node 1 10 that is registered 602 to ANR. The registration is received by the AC of the WLAN. In Figure 6, similar to Figure 5, the AC obtains information of cellular radio access node registered for ANR. However, as a difference to Figure 5, in Figure 6, the AC may obtain the registration directly from the cellular radio access node. It should be appreciated that the registration to the ANR may be performed to various core network entities for example as described in Figure 5, where the registration is performed to the AAA.

First the UE is served 606 by WLAN-AP1 612a. Since the cellular radio access node is registered to ANR, information identifying neighboring WLAN-APs is delivered to the cellular radio access node as described in item 514 of Figure 5. In this way the cellular radio access node may obtain 608 WLAN_UE_ID of the UE. Also, due to the registration to the ANR, the AC knows 610 the serving cellular radio access node of the UE.

The serving AP of the UE is changed to WLAN-AP2 612b. Typically, the serving AP may change to a new AP, for example due to better connection quality e.g. in terms of received power from the AP. The UE attempts 614 connecting to the mobile communications network via the new serving AP, WLAN- AP2. The attempt may be a re-authentication request to the mobile communications network. The re-authentication request from the UE may be received by the new serving WLAN-AP2 and forwarded 616 to the AC 1 13 for delivery to the core network. Accordingly, the authentication procedure and authentication requests of the UE may be similar to described in Figure 5. On the other hand, the re-authentication request may not need to be sent to the core network, if the AC stores the security context of the UE from previous authentication of the UE to the old WLAN-AP.

The AC obtains 616 from the authentication request the

WLANJJEJD of the UE and the WLAN-APJD of the new serving WLAN-AP2. The AC may determine that the UE attempting to connect is served by a cellular radio access node registered to ANR and send 618 the WLANJJEJD and the new WLAN-APJD to the cellular radio access node serving the UE.

The cellular radio access node may determine 620 whether the UE identified by the WLANJJEJD is still served by it. If the UE is still served, the cellular radio access may send 622 a confirmation message to the AC. The AC and the cellular radio access node store 624, 626 the new WLAN-APJD as a neighboring WLAN-AP to the cellular radio access node serving the UE. In this way the information of neighboring WLAN-APs to cellular radio access nodes may be updated in case the serving WLAN-AP of the UE changes. Figure 7 illustrates updating infornnation of neighboring WLAN-APs, when the serving eNB is changed. The updating takes place between entities of the mobile communications network. Examples of the entities are illustrated in Figure 1 . The cellular radio access network includes two radio access nodes eNB1 710a and eNB2 710b that are both registered 702a, 702b to ANR similar to described for the single cellular radio access node with item 502 in Figure 5. As a difference to Figure 5, the registration to the ANR is sent to the MME. In this way the information of the ANR registration of the old serving 704 cellular radio access node, eNB1 , of the UE may be delivered to the new serving cellu- lar radio access node, eNB2, of the UE, in handover of the UE from the eNB1 to the eNB2. The UE may be served 706 by a WLAN-AP at the same time it is connected to the eNB1 and/or the eNB2.

The eNB1 knows 708 the WLANJJEJD of the UE for example as described in item 608 in Figure 6. Also, due to the registration to the ANR, the AC knows 71 1 the serving cellular radio access node, eNB1 , of the UE.

The UE performs a handover 712 to the new cellular radio access node eNB2. After the handover, the UE is connected to the new cellular radio access node. The new cellular radio access node sends a message 714 to the MME informing the MME about the handover of the UE to the eNB2. The MME may send a response to the eNB2. The response may include information that the old cellular radio access node is registered to ANR. It should be appreciated that the response from the MME is not mandatory and therefore, it may be omitted.

The new eNB2 sends a query 716 to the WLAN for information re- garding one or more neighboring WLAN-APs serving the UE. The query may be triggered by the response from the MME indicating the eNB1 being registered to ANR. On the other hand it is possible to send the query without the response to find out if the UE is connected to the WLAN.

The query to the WLAN may include identifiers of the UE. The iden- tifiers may comprise a Cell Radio Network Temporary Identifier (C-RNTI) assigned to the UE by the eNB1 and a new C-RNTI assigned to the UE by the new cellular radio access node. The query may be received by the AC and use the new C-RNTI to replace the C-RNTI to update information of served UE by WLAN-APs.

In handover, the eNB1 and eNB2 may interconnected and capable of exchanging information including the last serving WLAN-AP of the UE, when served by the eNB1 . The information of the last serving WLAN-AP of the UE may be sent in the query to the AC. The connection between the eNBs may be an X2 connection defined in the LTE, for example.

The AC may send a response 718 that includes WLAN_UE_ID and WLAN_AP_ID of the serving WLAN_AP neighboring to the eNB2. The WLAN- APJD and WLANJJEJD may be determined as described in 512.

The eNB2 may store 720 the WLANJJEJD and the WLAN_AP_ID, similar to described in 408.

Figure 8 illustrates an apparatus 800 according to an embodiment. The apparatus includes neighbor unit 810, a communications interface 830 and a memory 840, which all may be electrically connected to a controller 820. The controller controls the operation of the neighbor unit, the communications interface and the memory. The communications interface may be capable of sending, causing to send, receiving and/or causing to receive data and/or sig- naling for performing communications between entities of a mobile communications network, for example the mobile communications network in Figure 1 .

The neighbor unit may perform one or more functionalities that may include determining, delivering and/or maintaining information related to neighbouring WLAN-APs. Although the units in Figure 8 have been described as a separate entity the units may be implemented in combined entities that perform the functionalities of the separate units. In one example the neighbour unit may be provided by the controller operating according to a computer program stored in the memory.

The neighbor unit may store information identifying neighboring WLAN-APs to cellular radio access nodes. The stored information may comprise information identifying the UE in a WLAN, the UE in a cellular radio access network or a global identifier for the UE. In WLAN the UE may be identified by a MAC address. In the cellular radio access network the UE may be identified by an identifier assigned in the cellular access network, e.g. the C- RNTI. An example of the global identifier is the GUTI assigned by the MME.

The information stored in the neighbor unit may form a map that identifies one or more neighboring WLAN-APs to a cellular radio access node. Identifiers of the UE may be stored associated with the identifier of WLAN-AP, when the UE is served by the WLAN-AP, and associated with the cellular radio access node, when the UE is served by the cellular radio access node. In this way an identifier of the UE in the WLAN may be associated with a WLAN-AP serving the UE. When the WLAN-AP is identified as neighboring to a cellular radio access node, the WLAN-AP and WLAN_UE_ID are mapped to the cellular radio access node and identifier of the UE outside the WLAN, e.g. in the cellular radio access network or globally by the GUTI.

It should be noted that Figure 8 shows only the elements and functional entities required for understanding the apparatus 800. It is apparent to a person skilled in the art that the apparatus may also comprise other functions and structures. The controller 820 may be a processor implemented with a separate digital signal processor provided with suitable software embedded on a computer readable medium, or with a separate logic circuit, such as an application specific integrated circuit (ASIC). More than one processor may be used to implement the controller.

The apparatus 800 may be comprised in a network entity, e.g. a HSS, AAA, S-GW, P-GW, MME, AC or a cellular radio access node. The appa- ratus 800 may comprise a circuitry, e.g. a controller, a chip, a processor, a micro controller, or a combination of such circuitries in network entity and cause the network entity to carry out the above-described functionalities.

The at least one processor 820 may comprise or be connected to circuitry for performing functionalities of determining, delivering and maintain- ing information related to neighbouring WLAN-APs. The circuitry may be implemented by the neighbour unit.

As used in this application, the term 'circuitry' may refer to all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and/or digital circuitry, and (b) combinations of circuits and soft- ware (and/or firmware), such as (as applicable): (i) a combination of processors) or (ii) portions of processor(s)/software including digital signal processors), software, and memory(ies) that work together to cause an apparatus to perform various functions, and (c) circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. This definition of 'circuitry' applies to all uses of this term in this application. As a further example, as used in this application, the term 'circuitry' would also cover an implementation of merely a processor (or multiple processors) or a portion of a processor and its (or their) accompanying software and/or firmware. The term 'circuitry' would also cover, for example and if applicable to the particular element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a mobile communications network device, or another network device.

The apparatus may be implemented as an entity or a module of the entity of the mobile communications network. Examples of the entities com- prise for example a HSS, AAA, S-GW, P-GW, AC or a cellular radio access node.

In the foregoing description the embodiments have been described with reference to specific entities of the mobile communications network. However, the functionalities performed by a specific entity may be performed also by one or more other entities examples of which are described with reference to Figure 1 . For example, a dedicated network element, a cellular radio access node, an RNC, an AC, an AAA, MME, and/or P-GW may all store information identifying neighboring WLAN-APs to cellular radio access nodes. For a further example, the authentication procedure of the UE may be performed by the AAA or the HSS.

The techniques and methods described herein, for example in Figures 2a, 2b, 3, 4, 5, 6 and 7, may be implemented by various means. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or combinations thereof. For a hardware implementation, the apparatus(es) of embodiments may be implemented within one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, micro- processors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, the implementation can be carried out through modules of at least one chip set (e.g. procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit and executed by processors. The memory unit may be implemented within the processor or externally to the processor. In the latter case, it can be communicatively coupled to the processor via various means, as is known in the art. Additionally, the components of the systems described herein may be rearranged and/or complemented by additional components in order to facilitate the achievements of the various aspects, etc., described with regard thereto, and they are not limited to the precise configurations set forth in the given figures, as will be appreciated by one skilled in the art.

Apparatuses described in the embodiments and corresponding modules and/or other corresponding devices or apparatuses implementing the functionality of a corresponding apparatus described with an embodiment comprise not only prior art means, but also means for maintaining information identifying cellular radio access nodes registered for receiving information regarding neighboring wireless local area network access points, in a mobile communications network comprising a cellular radio access network and a wireless local area network, obtaining information identifying a user equipment in the mobile communications network and information identifying wireless local area network access point serving the user equipment, determining the wireless local area access point as a neighboring wireless local area access point to a cellular radio access node serving the user equipment, causing to send information identifying the wireless local area network access point serv- ing the user equipment to the cellular radio access node serving the user equipment, when the cellular radio access node serving the user equipment is registered for receiving information regarding neighboring wireless local area network access points.

On the other hand apparatuses described in the embodiments and corresponding modules and/or other corresponding devices or apparatuses implementing the functionality of a corresponding apparatus described with an embodiment comprise not only prior art means, but also means for obtaining an authentication request for a user equipment to a mobile communications network via a wireless local area network access point, wherein the authentica- tion request comprises information identifying the user equipment in the cellular radio access network and information identifying the wireless local area network access point, causing to send the information identifying the wireless local area network access point and information identifying the user equipment in the cellular radio access network to network node maintaining information on cellular radio access nodes registered for receiving information on neighboring wireless local area network access points .obtaining, in response to the information sent to the network node maintaining information on cellular radio access nodes registered for receiving information on neighboring wireless local area network access points, information identifying a cellular radio access node serving the user equipment and registered for receiving information regarding neighboring wireless local area network access points, and causing to send the information identifying the cellular radio access node serving the user equipment and the information identifying the wireless local area network access point to an access controller or a wireless local area network access point serving the user equipment in the wireless local area network as part of an au- thentication procedure.

On the other hand apparatuses described in the embodiments and corresponding modules and/or other corresponding devices or apparatuses implementing the functionality of a corresponding apparatus described with an embodiment comprise not only prior art means, but also means for storing in- formation identifying at least one neighboring wireless local area network access point to a cellular radio access node, in a mobile communications network comprising a cellular radio access network and a wireless local area network, obtaining information identifying a user equipment and a wireless local area network access point serving the user equipment, determining whether the user equipment is served by the cellular radio access node identified in the stored information, and storing the information identifying the wireless local area network access point serving the user equipment as neighboring wireless local area network access point to the cellular radio access node, when the user equipment is served by the cellular radio access node.

More precisely, they comprise means for implementing functionality of a corresponding apparatus described with an embodiment and they may comprise separate means for each separate function, or means may be configured to perform two or more functions.

Present apparatuses comprise processors and memory that can be utilized in an embodiment. For example, the neighbor unit 810 may be software applications, or modules, or units configured as arithmetic operations, or as programs (including an added or updated software routine), executed by an operation processor. Programs, also called program products, including software routines, applets and macros, can be stored in any apparatus-readable data storage medium and they include program instructions to perform particular tasks. All modifications and configurations required for implementing functionality of an embodiment may be performed as routines, which may be implemented as added or updated software routines, application circuits (ASIC) and/or programmable circuits. Further, software routines may be downloaded into an apparatus. The apparatus or a corresponding module may be configured as a computer or a microprocessor, such as single-chip computer ele- ment, including at least a memory for providing storage area used for arithmetic operation and an operation processor for executing the arithmetic operation. An example of the operation processor includes a central processing unit. The memory may be removable memory detachably connected to the apparatus.

Thus, according to an embodiment, the apparatus comprises processing means configured to carry out any of the embodiments of Figures 2a to 7. In an embodiment, the at least one processor 820, the memory 840 and a computer program code form an embodiment of processing means for carrying out the embodiments of the invention.

Embodiments described herein may be implemented in an arrangement, for example a mobile communications network, where various techniques and methods described herein may be performed in a single entity or a plurality of entities. The entities may be logical or physical entities, for example AAAs, HSSs, cellular radio access nodes, WLAN-APs, WLAN ACs, S- GW, P-GW or S-GW/P-GW, that may be implemented by general-purpose servers, hosts or nodes.

Embodiments as described may also be carried out in the form of a computer process defined by a computer program. The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, which may be any entity or device capable of carrying the program. For example, the computer program may be stored on a computer program distribution medium readable by a computer or a processor. The computer program medium may be, for example but not limited to, a record medium, computer memory, read-only memory, electrical car- rier signal, telecommunications signal, and software distribution package, for example.

Even though the invention has been described above with reference to an example according to the accompanying drawings, it is clear that the invention is not restricted thereto but can be modified in several ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, the embodiment.

It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. Further, it is clear to a person skilled in the art that the described embodiments may, but are not required to, be combined with other embodiments in various ways.

Claims

1 . A method, comprising:

maintaining information identifying cellular radio access nodes regis- tered for receiving information regarding neighboring wireless local area network access points, in a mobile communications network comprising a cellular radio access network and a wireless local area network;

obtaining information identifying a user equipment in the mobile communications network and information identifying wireless local area net- work access point serving the user equipment;

determining the wireless local area access point as a neighboring wireless local area access point to a cellular radio access node serving the user equipment;

causing to send information identifying the wireless local area net- work access point serving the user equipment to the cellular radio access node serving the user equipment, when the cellular radio access node serving the user equipment is registered for receiving information regarding neighboring wireless local area network access points.

2. A method according to claim 1 , wherein the information identifying the wireless local area network access point and user equipment are received in response to an authentication procedure of the user equipment to the mobile communications network,

3. A method according to claim 2, wherein said authentication procedure is performed by a core network node, for example an authentication agent or a mobility management entity, of the mobile communications network.

4. A method according to any one of the preceding claims, compris- ing:

causing to send the information identifying the cellular radio access node to a core network node performing an authentication procedure of the user equipment to the mobile communications network,.

5. A method according to any one of the preceding claims, comprising:

causing to send information identifying the user equipment to the cellular radio access node serving the user equipment.

6. A method according to any one of the preceding claims, comprising:

causing to send information identifying the cellular radio access node and information identifying the wireless local area network access point to an access controller or a wireless local area network access point serving the user equipment in the wireless local area network.

7. A method according to any one of the preceding claims, wherein the information identifying the cellular radio access node and information iden- tifying the wireless local area network access point are delivered directly to the access controller or a wireless local area network access point serving the user equipment in the wireless local area network, or as part of an authentication procedure of the user equipment.

8. A method according to claim 7, wherein the information identifying the cellular radio access node and information identifying the wireless local area network access point are delivered directly to the access controller or the wireless local area network access point, when an incomplete procedure, for example authentication procedure, towards the wireless local area network access point or the access controller is determined.

9. A method comprising:

obtaining an authentication request for a user equipment to a mobile communications network via a wireless local area network access point, wherein the authentication request comprises information identifying the user equipment in the cellular radio access network and information identifying the wireless local area network access point;

causing to send the information identifying the wireless local area network access point and information identifying the user equipment in the cel- lular radio access network to network node maintaining information on cellular radio access nodes registered for receiving information on neighboring wireless local area network access points;

obtaining, in response to the information sent to the network node maintaining information on cellular radio access nodes registered for receiving information on neighboring wireless local area network access points, information identifying a cellular radio access node serving the user equipment and registered for receiving information regarding neighboring wireless local area network access points; and

causing to send the information identifying the cellular radio access node serving the user equipment and the information identifying the wireless local area network access point to an access controller or a wireless local area network access point serving the user equipment in the wireless local area network as part of an authentication procedure.

10. A method according to claim 9, wherein said authentication request is obtained in an authentication procedure performed by a core network node, for example an authentication agent or a mobility management entity, of the mobile communications network.

1 1 . A method comprising:

storing information identifying at least one neighboring wireless local area network access point to a cellular radio access node, in a mobile communications network comprising a cellular radio access network and a wireless local area network;

obtaining information identifying a user equipment and a wireless local area network access point serving the user equipment;

determining whether the user equipment is served by the cellular radio access node identified in the stored information; and

storing the information identifying the wireless local area network access point serving the user equipment as neighboring wireless local area network access point to the cellular radio access node, when the user equipment is served by the cellular radio access node.

12. A method according to claim 1 1 , wherein the information identi- fying user equipment and the wireless local area network access point serving the user equipment are received as a part of an authentication procedure of the user equipment to the mobile communications network.

13. A method according to claim 1 1 or 12, wherein the information identifying a user equipment and a wireless local area network access point serving the user equipment are received from the wireless local area network and the method comprises:

causing to send a response to the wireless local area network, said response indicating that the user equipment is served by the cellular radio ac- cess node.

14. A method according to any one of claims 1 1 to 13, wherein said authentication procedure is performed by a core network node, for example an authentication agent or a mobility management entity, of the mobile communi- cations network.

15. A method according to any one of claims 1 1 to 14, wherein the method comprises a handover of the user equipment from an old cellular radio access node to a new cellular radio access node, and a query is sent to an access controller or a wireless local area network access point serving the user equipment in the wireless local area network for connectivity of the user equipment to the wireless local area network.

16. A method according to any one of claims 1 1 to 15, wherein a re- sponse from the wireless local area network includes information identifying the user equipment and the wireless local area network access point serving the user equipment.

17. An apparatus comprising,

at least one processor and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to:

maintaining information identifying cellular radio access nodes regis- tered for receiving information regarding neighboring wireless local area net- work access points, in a mobile communications network comprising a cellular radio access network and a wireless local area network;

18. An apparatus comprising:

causing to send the information identifying the wireless local area network access point and information identifying the user equipment in the cellular radio access network to network node maintaining information on cellular radio access nodes registered for receiving information on neighboring wireless local area network access points;

obtaining, in response to the information sent to the network node maintaining information on cellular radio access nodes registered for receiving information on neighboring wireless local area network access points, information identifying a cellular radio access node serving the user equipment and registered for receiving information regarding neighboring wireless local area network access points; and causing to send the information identifying the cellular radio access node serving the user equipment and the information identifying the wireless local area network access point to an access controller or a wireless local area network access point serving the user equipment in the wireless local area network as part of an authentication procedure.

19. An apparatus comprising:

at least one processor and at least one memory including a computer program code, wherein the at least one memory and the computer pro- gram code are configured to, with the at least one processor, cause the apparatus at least to:

20. A computer program product that when executed by a computer, cause execution of a method according to any one of claims 1 to 16.

21 . A computer program embodied on a computer -readable storage medium, the computer program comprising program to execute a process comprising:

maintaining information identifying cellular radio access nodes registered for receiving information regarding neighboring wireless local area network access points, in a mobile communications network comprising a cellular radio access network and a wireless local area network; obtaining infornnation identifying a user equipment in the mobile communications network and information identifying wireless local area network access point serving the user equipment;

causing to send information identifying the wireless local area network access point serving the user equipment to the cellular radio access node serving the user equipment, when the cellular radio access node serving the user equipment is registered for receiving information regarding neighboring wireless local area network access points.

22. A computer program embodied on a computer -readable storage medium, the computer program comprising program to execute a process comprising:

causing to send the information identifying the wireless local area network access point and information identifying the user equipment in the cellular radio access network to network node maintaining information on cellular radio access nodes registered for receiving information on neighboring wire- less local area network access points;

23. A computer program embodied on a computer -readable storage medium, the computer program comprising program to execute a process comprising:

obtaining information identifying a user equipment and a wireless lo- cai area network access point serving the user equipment;