WO2013166679A1

WO2013166679A1 - Method and apparatus for managing a wireless connection

Info

Publication number: WO2013166679A1
Application number: PCT/CN2012/075280
Authority: WO
Inventors: Yang Liu; Haitao Li; Dajiang Zhang
Original assignee: Nokia Inc
Current assignee: Nokia Inc
Priority date: 2012-05-10
Filing date: 2012-05-10
Publication date: 2013-11-14
Anticipated expiration: 2014-11-10

Description

METHOD AND APPARATUS FOR MANAGING A WIRELESS CONNECTION

TECHNICAL FIELD

[0001] The present application relates generally to managing a wireless connection, for example in connection with a connection failure.

BACKGROUND

[0002] Wireless communication between electronic devices requires that devices participating in the communication, for example a base station and a mobile station, are configured to conform to an agreed framework for communication. The agreed framework comprises defined procedures that are used to effect the communication in the framework context, wherein the context may comprise for example air interface resources, or radio resources, such as at least one frequency band. Such frameworks may be known as radio access technologies, or RATs. A RAT may be defined in industry standards that device manufacturers can refer to when designing products such that they are capable of communicating according to the RAT.

[0003] When standards are used correctly, interoperability between devices from a plurality of suppliers may be achieved. For example, a cellular telephone produced by a first manufacturer may be capable of communicating with a cellular telephone produced by a second manufacturer, using a base station produced by a third manufacturer and a core network produced by a fourth manufacturer.

[0004] In general in cellular communications, mobiles communicate with base stations using a wireless air interface. As mobiles roam in the network coverage area from the coverage area of a first cell to a coverage area of a second cell, the mobiles may undergo a procedure known as a handover. A handover changes the base station a mobile is attached to, in effect changing base station to account for the fact that another base station is better suited to serve the mobile given its changed location in the network coverage area. In cases where a mobile detects that a radio connection to a base station it is attached to is severed, for example due to a transient problem with the radio path, the mobile may be configured to attempt a procedure known as a re- establishment with the base station. A successful re-establishment may allow the mobile to continue using the connection without needing to participate in new connection establishment procedures.

[0005] Frequency management on a cellular network level may be used to re-use frequencies, so that adjacent cells are configured to use different frequencies. Configuring cells to be smaller allows for re-using frequencies to a greater extent, which increases network capacity. Another way to increase network capacity is to provide separate hotspots in areas where usage is particularly concentrated, wherein such hotspots may be based on a different RAT than the cellular network. For example, where the cellular network operates in accordance with wideband code division multiple access, WCDMA, a hotspot may operate in accordance with a wireless local area network, WLAN, RAT. In this example, a mobile capable of accessing both RATs can use the hotspot for data transmission when in range of the hotspot, and otherwise rely on the WCDMA network.

[0006] One way to increase network capacity is to provide access points operably connected to cellular base stations. Such access points may provide additional connectivity options for mobiles in the sense that mobiles may communicate either with a cellular base station either directly, or via the access point. Such access points may operate using the same RAT as the cellular base station they are attached to, or a modified version of the same RAT, for example. Such access points may also, or alternatively, be configured to use a non-cellular RAT.

SUMMARY

[0007] Various aspects of examples of the invention are set out in the claims.

[0008] According to a first aspect of the present invention, there is provided an apparatus comprising a receiver configured to receive a first credential associated with a user equipment, the receiver further configured to receive a connection re-establishment request from the user equipment, at least one processing core configured to compare a second credential received from the user equipment to the first credential and responsive to the first credential matching the second credential, the at least one processing core is configured to accept the connection re-establishment request.

[0009] According to a second aspect of the present invention, there is provided a method, comprising receiving a first credential associated with a user equipment, receiving a connection re-establishment request from the user equipment, comparing a second credential received from the user equipment to the first credential, and responsive to the first credential matching the second credential, accepting the connection re-establishment request.

[0010] According to a third aspect of the present invention, there is provided an apparatus, comprising at least one processor, at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least detect that a radio link failure has occurred between the apparatus and an access point providing, for the apparatus, access to a cellular base station, and responsive to detecting the radio link failure, transmit a connection re-establishment request to the access point, the connection re-establishment request comprising a first credential and a local connection identity valid between the apparatus and the access point.

[0011] According to a fourth aspect of the present invention, there is provided a method, comprising detecting that a radio link failure has occurred between the apparatus and an access point providing, for the apparatus, access to a cellular base station, and responsive to detecting the radio link failure, transmitting a connection re-establishment request to the access point, the connection re-establishment request comprising a first credential and a local connection identity valid between the apparatus and the access point.

[0012] According to further aspects of the present invention, there are provided computer programs, including computer programs embodimed on computer-readable media, configured to cause methods in accordance with aspects of the present invention to be performed, when run.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] For a more complete understanding of example embodiments of the present invention, reference is now made to the following descriptions taken in connection with the accompanying drawings in which:

[0014] FIGURE 1 illustrates an example system capable of supporting at least some embodiments of the invention;

[0015] FIGURE 2 illustrates a block diagram of an apparatus such as, for example, a mobile terminal or an access point, in accordance with an example embodiment of the invention;

[0016] FIGURE 3 is a signaling diagram illustrating signaling according to one example embodiment of the present invention, and [0017] FIGURE 4 is a signaling diagram illustrating signaling according to one example embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0018] An example embodiment of the present invention and its potential advantages are understood by referring to FIGURES 1 through 4 of the drawings.

[0019] FIGURE 1 illustrates an example system capable of supporting at least some embodiments of the invention. Illustrated is a cellular communications network, comprising base station 120, which may be for example a WCDMA base station, which is known as a node-B. Alternatively base station 120 may be a long term evolution, LTE, base station, which is known as an eNB. Base station 120 may also be a different kind of cellular base station but in the discussion below it discussed for the sake of consistency in terms of an eNB in an LTE network. Base station 120 may be connected to a first core network entity 130 such as, for example, a MME by means of interface 121. An interface between an eNB and a MME may be referred to as an SI interface. First core network entity 130 may be connected to second core network entity 140 by means of interface 131. In an LTE system, the second core network entity may be a serving gateway and interface 131 may be a SI 1 interface. Second core network entity 140 may be connected to internet 150 by means of interface 141. At least one further node, such as for example a PDN gateway, may be disposed between the second core network node 140 and internet 150. In a WCDMA network embodiment, first core network 130 entity may be a serving general packet radio service, GPRS, support node, SGSN, and second core network entity 140 may be a gateway general packet radio service, GPRS, support node, GGSN, for example.

[0020] Core network nodes 130 and 140 may provide for control of a cellular communications system, which may include functions relating to authenticating users, authorizing traffic flows, billing, roaming, interworking with other networks and switching. Switching may comprise, for example, that data packets comprising digital speech samples are conveyed from a first mobile to a second mobile and vice versa, to provide for a bidirectional packet-based voice call.

[0021] A mobile may access the internet via a signaling path comprising base station 120, first core network node 130 and second core network node 140. FIG. 1 illustrates also access point 110, which is arranged to communicate with base station 120 over link 115. Link 115 may a wire-line link or link 115 may be a wireless link in conformance with a cellular standard base station 120 supports, for example where base station 120 is an LTE eNB, wireless link 115 may be an LTE wireless link. Link 115 may comprise an uplink for conveying information from access point 110 to base station 120, and a downlink for conveying information from base station 120 to access point 110. Where link 115 is wire-line, it may be configured according to a modified S 1 interface, for example.

[0022] Mobiles 110 illustrated in FIG. 1 are disposed within the cell coverage area of a cell controlled by base station 120. Mobiles 110 may communicate with base station 120 directly, as illustrated by wireless connection 106, or via access point 110. When communicating with base station 120 via access point 110, information may be conveyed to and from mobiles 100 via wireless link 105 and link 115. Wireless links 105 may comprise an uplink and downlink, like wireless link 115, to allow for bidirectional data communication with access point 110. In some embodiments, wireless links 105 operate using the same radio resources, such as spectrum band or spreading codes, as link 106. In other embodiments, wireless links 105 use different radio resources than link 106. For example, wireless links 105 may use a license-exempt frequency band while link 106 may use a frequency band allocated for use in cellular communications. As noted above, link 115 may be a wire-line link in which case it doesn't use any radio resources. Where link 115 is wireless, it may use the same radio resources as link 106 and/or wireless links 105. Alternatively it may use different radio resources than link 106 and/or wireless links 105.

[0023] The RAT used for wireless links 105 may be the same, or similar, to the RAT used for wireless linkl06. Wireless link 106 may be referred to as a cellular wireless link since it connects a cellular mobile to a base station. In embodiments where the RAT used for cellular wireless links is LTE, the RAT in use for wireless links 105 may be a modified LTE RAT, for example.

[0024] Where one of mobiles 100 is in communication with base station 120 and there is a disturbance in wireless link 106, wireless link 106 may experience a radio link failure. By radio link failure it is meant that a wireless connection is lost and communication is interrupted. Responsively, the mobile may invoke a re-establishment procedure with base station 120 to recover wireless link 106. Should re-establishment fail, the mobile would have to repeat the radio link establishement procedures with the cellular network that were conducted to initialize wireless link 106 and bearers carrier over it, which may be a time-consuming process. In contrast, in re-establishment base station 120 will work with the mobile, using a context of the mobile stored in base station 120, to resume communications after the radio link failure without needing to undergo new initialization procedures. New initialization procedures may comprise at least one of a new radio resource control, RRC, connection establishment procedure and a new authentication procedure involving a core network. In other words, successful re-establishment may provide for avoiding at least one new initialization procedure. Avoiding an initialization procedure may save time and signaling in the network, as a new initialization procedure would take time to complete. Signaling for its part would consume energy and cause interference in the cell. In connection with participating in wireless link 106, base station 120 may store security information, such as security keys or at least one credential, which may be used in re- establishment to ensure that the mobile transmitting the re-establishment request is the same mobile as the one that participated in wireless link 106 before the radio link failure.

[0025] When mobile 110 accesses the cellular network via access point 110, data may be conveyed through access point 110 in a transparent way. Being conveyed in a transparent way may comprise that a local authentication is peformed between access point 110 and the mobile, and cellular-level authentication and security procedures are performed between the mobile and first core network node 130, or between the mobile and base station 120, for example. Ciphering of the data stream from the mobile to the cellular network may be done between the mobile and base station 120, for example. Where access point 110 isn't involved in security procedures, aside from forwarding messages between the mobile and base station 120, and/or where access point 110 isn't capable of opening the ciphering of data, access point 110 may be unfurnished with cellular-level security information. Where the cellular system is an LTE system, an evolved packet system, EPS, security context may be established between the mobile and base station 120. Also in an LTE example cellular system, actual data may be conveyed between the mobile and a core network node, such as a packet data network, PDN, gateway, PDN GW, in an EPS bearer.

[0026] Where one of mobiles 100 is in wireless communication with access point 110, and not base station 120, and there is a disturbance in wireless link 105, wireless link 105 may experience a radio link failure. Since at least in some embodiments access point 110 lacks cellular security information used in re-establishment, access point 110 may be unable to participate in the role of a base station in a re-establishment procedure requested by the mobile. In other words, while access point 110 may be capable of performing a local authentication with the mobile, access point 110 may be unable to provide base station 120 with guarantees that the mobile is the same one as the mobile participating in wireless link 105 prior to the radio link failure. Since the mobile is to be provided with access to the cellular network which comprises base station 120, it needs authentication on the level of the cellular system. Base station 120 and core network nodes 130 and 140 may be configured to not accept the local authentication performed by access point 110 as valid for granting access after the re-establishment of wireless link 105.

[0027] To facilitate re-establishement of wireless link 105, base station 120 may be configured to provide to access point 110 at least one credential for use in re-establishing wireless link 105 subsequent to a radio link failure on wireless link 105. Base station 120 may be configured to provide the at least one credential before the radio link failure occurs. Base station 120 may be configured to provide the at least one credential as part of a connection set-up when the mobile is granted access to the cellular system via access point 110. The at least one credential may comprise, for example, a message authentication code for integrity, MAC-I. Responsive to receiving the at least one credential, access point 110 may be configured to store the at least one credential in a memory comprised in access point 110. Access point 110 may be configured to store the at least one credential for as long as the mobile accesses the cellular system via access point 110. In some embodiments, access point 110 is configured to store the at least one credential for a predetermined time after the mobile stops accessing the cellular system via access point 110. Where the mobile performs a handover to access the cellular system via a different node than access point 110, and the handover fails, the mobile may attempt to reestablish connectivity via access point 110, which may participate in the handover as a source node.

[0028] Responsive to receiving a re-establishment request from a mobile, access point 110 may be configured to compare the at least one credential it has received from base station 120 to a corresponding at least one credential it has received from the mobile, for example as part of the re-establishement request. The mobile may be capable of deriving the at least one credential independently, since it participates in cellular-level security procedures with the cellular network and the at least one credential relates to the cellular system. Access point 110 may be configured to only accept the re-establishment request when the at least one credential received from the mobile matches the at least one credential access point 110 has received from the cellular system. Accepting the re-establishment request may comprise, for example, transmitting a re-establishment message from access point 110 to base station 120, to inform the cellular system that the mobile has requested re-establishment and that the mobile has been authenticated in access point 110 based on the at least one credential. Alternatively, accepting the re-establishment request may comprise resuming communications with the mobile via wireless link 105, and concealing the occurrence of the radio link failure from base station 120 and the rest of the cellular system.

[0029] By providing the at least one credential to access point 110, base station 120 may in effect at least in part delegate authentication responsibility to access point 110, which may reduce the amount of signaling necessary in re-establishment. Since re-establishment of a radio link may be a time-sensitive procedure, reducing the necessary amount of signaling may increase the likelihood that the procedure is successfully completed before the radio link failure becomes irreversible.

[0030] In general there is provided an apparatus, such as for example an access point or a control device for controlling an access point, comprising a receiver configured to receive a first credential associated with a user equipment. The user equipment may be a user equipment participating in a wireless connection with the apparatus at the time the first credential is received. The apparatus may be configured to provide access for the user equipment to a cellular base station, via a wireless link from the user equipment to the apparatus and a wired or wireless link from the apparatus to the cellular base station. Where the apparatus comprises a control device, the receiver may comprise an input pin enabled to receive information internally in an access point, when the control device is installed to control operation of the access point.

[0031] The receiver may be configured to receive a connection re-establishment request from the user equipment. The receiver may comprise two sub-receivers, one for a link toward a cellular base station configured to receive information from the cellular base station and another toward a user equipment, configured to receive information from the user equipment.

[0032] The apparatus may comprise at least one processing core configured to compare a second credential received from the user equipment to the first credential, and responsive to the first credential matching the second credential, to accept the connection re-establishment request. [0033] Responsive to the second credential not matching the first credential, the at least one processing core may be configured to cause the apparatus to reject the re-establishment request. Rejecting the re-establishment request may comprise, for example, discarding and ignoring the request or causing an error message to be transmitted to the user equipment.

Rejecting the re-establishment request may also comprise causing a message to be transmitted to the cellular base station informing it of a failed re-establishement. A cellular system the base station is comprised in may use such messaged for compiling statistics, as frequent failed re- establishments may imply problems in network function, or attempts to access the network illegally.

[0034] In some embodiments, the apparatus is an access point embodied in a mobile user equipment configured to provide access point services to other mobile user equipments.

[0035] In some embodiments, the second credential is received from the user equipment comprised in the connection re-establishment request. In some embodiments, the second credential is received from the user equipment responsive to a request issued by the access point. In some embodiments, the first credential is received from the cellular base station. In some embodiments, the first credential is received from a server in the cellular system where the cellular base station is comprised. In some embodiments, the apparatus is configured to request and responsively receive the first credential from the server in connection with commencing providing access to the user equipment. The request may comprise an identity of the user equipment access is provided to by the apparatus.

[0036] In embodiments where the first credential is received from the cellular base station, the first credential may be received in the apparatus comprised in a message comprised in a context setup procedure. In other embodiments, the first credential may be received from the cellular base station in the apparatus comprised in a message comprised in a downlink procedure.

[0037] In some embodiments, accepting the connection re-establishment request comprises causing a connection re-establishment message to be transmitted to the user equipment. Accepting the connection re-establishment request may also comprise causing a connection re-establishment message to be transmitted to the cellular base station.

[0038] In some embodiments, the at least one processing core is configured to cause the apparatus to participate in a local authentication procedure with the user equipment. The local authentication procedure may be conducted at least one of in connection with initial access and re-authentication. In some embodiments, the local authentication procedure comprises signaling only between the apparatus and the user equipment, and the apparatus is competent to decide on success or failure of the local authentication procedure.

[0039] In some embodiments, the apparatus is configured to convey cellular security- related messages between the cellular base station and the user equipment without participating in the cellular security procedures. Not participating may comprise not modifying, creating or discarding the cellular security -related messages. In some embodiments, the apparatus is not enabled to open ciphering used by the user equipment and the cellular base station to secure the cellular security-related messages.

[0040] In some embodiments, the first and second credentials comprise message authentication codes for integrity, MAC-I. The user equipment and the cellular base station are capable of deriving message authentication codes for integrity relating to the user equipment, using security information of the cellular communication system. The cellular communication system is furnished with security information and authentication capability to enable functions including reliable charging and communication privacy.

[0041] In general there is provided a second apparatus, such as for example a user equipment or a control apparatus such as a processor, chip or chipset for inclusion in a user equipment, to control the operation of the user equipment. The second apparatus may be caused to perform detecting that a radio link failure has occurred between the second apparatus and an access point providing, for the second apparatus, access to a cellular base station. Responsive to detecting the radio link failure, the second apparatus may be configured to transmit a connection re-establishment request to the access point, the connection re-establishment request comprising a first credential. The connection re-establishment request may also comprise a local identity valid between the second apparatus and the access point. The access point may be physically distinct from the cellular base station, as illustrated in FIG. 1. The second apparatus may be capable of deriving the first credential. The first credential may comprise a message

authentication code for integrity. The first credential may be derived from security information of the cellular communication system. The access point may be unable to access or store the security information of the cellular communication system.

[0042] FIGURE 3 is a signaling diagram illustrating signaling according to one example embodiment of the present invention. Along the top of the figure are illustrated, from left to right, first a user equipment, UE, second an access point, LTE-Hi AP, third a cellular base station, associated eNB and and fourth a core network node, MME. Time increases from top to bottom.

[0043] In phase 01, a user equipment transmits a connection request to the access point, which is illustrated as RRCConnectionRequest. In phase 02, the access point responds by sending a setup message back to the user equipment, which is illustrated as

RRCConnectionSetup. In phase 03, the user equipment responds by transmitting a

RRCConnectionSetupComplete message.

[0044] Following phase 3, or in connection with phases 01, 02 and 03, a local authentication may be performed between the user equipment and the access point. As a result of the local authentication, the user equipment and access point know each other and may be capable of exchanging secured messages with each other. Secured may in this context mean, for example, ciphered and/or digitally signed.

[0045] Following local authentication, the user equipment may be configured to transmit a connection request toward the cellular system via the access point. This is illustrated as phase 04 EPSConnectionRequest, which is forwarded from the access point to the cellular base station in phase 05, and from the cellular base station to the core network node in phase 06. Responsive to receiving the signal from the user equipment, the core network node may be configured to activate an association of the user equipment and the cellular system. The association is illustrated in FIG. 3 as an evolved packet system, EPS, association.

[0046] Following association establishment, cellular system-level authentication may be performed between the user equipment and the cellular network. This is illustrated in FIG.3 A "Authentication/security". The AP may act only as a data pipe for the cellular system-level authentication, passing messages to and from the user equipment without interfering with their content. Following cellular system-level authentication, the core network node may transmit an initial context setup request to the cellular base station, which is illustrated as phase 07.

[0047] Responsive to phase 07, or responsive to the cellular system-level authentication, system-level security may be activated between the user equipment and the cellular base station. The cellular base station may be configured to calculate, or derive, at least one credential such as for example a MAC-I for use in potential re-establishment of a radio link between the user equipment and the access point. Although illustrated as occurring between phases 07 and 08, the deriving may occur also at other phases of the illustrated procedure after the cellular base station has been made aware of an identity of the user equipment.

[0048] In phase 08, the cellular base station may transmit an initial context setup request to the access point, wherein the initial context setup request may comprise the derived at least one credential, and optionally a next hop chaining counter, NCC. A NCC is a parameter for security operations. Subsequent to phase 08, a packet-based and secured service, illustrated as EPS service, is active from the user equipment via the access point to the cellular core network.

[0049] A radio link failure occurs during the active packet-based service in a radio link between the user equipment and the access point. The radio link failure is illustrated in FIG. 3 as "RLF occurred". Responsive to detecting the radio link failure, the user equipment may be configured to transmit a re-establishement request comprising a copy of the at least one credential derived in the user equipment, to the access point. This is illustrated as phase 09 in FIG. 3. Subsequent to phase 09, the access point and the user equipment optionally undergo a local security procedure, after which the access point may be configured to verify that the at least one credential received from the user equipment matches the at least one credential the access point has received from the cellular base station. Responsive to the credentials matching, and only then, is the access point configured to accept the re-establishment. Accepting the re- establishment is illustrated in FIG. 3 by phases 10, 11 and 12 wherein the access point transmits a RRCConnectionReestablishment message toward the user equipment, receives a

RRCConnectionReestablishmentComplete message in response, and transmits a re-establishment message toward the cellular base station.

[0050] After the re-establishment is complete, the packet-based service which was interrupted in connection with the radio link failure, may resume. The re-establishment procedure may render it unnecessary to repeat the cellular system-level authentication procedure already performed in connection with initiating the packet-based service.

[0051] FIGURE 4 is a signaling diagram illustrating signaling according to one example embodiment of the present invention. In the upper part of the figure are illustrated first user equipment, UE, second access point, AP, and finally base station, BS. Time increases from top to bottom.

[0052] In optional phase 410, the UE and AP undergo a security procedure between each other, this being an access point-level security procedure not involving cellular system security information. In optional phase 420, the UE undergoes a cellular system-level authentication procedure with the cellular network, which may involve the BS and/or a core network entity not illustrated in FIG. 4. In phase 430, the BS signals to the AP that the UE may begin to communicate with the cellular system via the AP. The BS may deliver a credential relating to the UE to the AP, comprised in the message of phase 430 or otherwise. In some embodiments, the AP is configured to obtain the credential from a server node separate from the BS.

[0053] In phase 440 the UE accesses the cellular system via the AP. In other words, information may be conveyed in both directions between the UE and BS via the AP. The connection between UE and AP may be wireless, and the connection between AP and BS may be either wire-line or wireless.

[0054] In phase 450, a radio link failure occurs between the UE and AP. The radio link failure may be due to a transient deep fade, a tram blocking a radio path between UE and AP or another reason, for example. Responsive to the radio link failure, the UE may be configured to transmit a re-establishment request to the AP, phase 460. The re-establishment request may comprise a credential relating to the UE of the same type as the credential obtained by the AP. In phase 470, the AP may be configured to compare the credential received from the UE to the credential it has obtained earlier, and only in case the credentials match, is the AP configured to accept the re-establishment request and initiate resumption of the access of the UE to the cellular system.

[0055] FIGURE 2 illustrates a block diagram of an apparatus 10 such as, for example, a mobile terminal or an access point, in accordance with an example embodiment of the invention. A mobile terminal may be configured to act as an access point. While several features of the apparatus are illustrated and will be hereinafter described for purposes of example, other types of electronic devices, such as mobile telephones, mobile computers, portable digital assistants, PDAs, pagers, laptop computers, desktop computers, gaming devices, televisions, routers, home gateways, and other types of electronic systems, may employ various embodiments of the invention. An access point may also be non-mobile.

[0056] As shown, the apparatus 10 may include at least one antenna 12 in

communication with a transmitter 14 and a receiver 16. Alternatively transmit and receive antennas may be separate. The mobile terminal 10 may also include a processor 20 configured to provide signals to and receive signals from the transmitter and receiver, respectively, and to control the functioning of the apparatus. Processor 10 may be configured to control the functioning of the transmitter and receiver by effecting control signaling via electrical leads to the transmitter and receiver. Likewise processor 10 may be configured to control other elements of apparatus 10 by effecting control signaling via electrical leads connecting processor 10 to the other elements, such as for example a display or a memory. The processor 20 may, for example, be embodied as various means including circuitry, at least one processing core, one or more microprocessors with accompanying digital signal processor(s), one or more processor(s) without an accompanying digital signal processor, one or more coprocessors, one or more multi- core processors, one or more controllers, processing circuitry, one or more computers, various other processing elements including integrated circuits such as, for example, an application specific integrated circuit, ASIC, or field programmable gate array, FPGA, or some combination thereof. Accordingly, although illustrated in FIG. 2 as a single processor, in some embodiments the processor 20 comprises a plurality of processors or processing cores. Signals sent and received by the processor 20 may include signaling information in accordance with an air interface standard of an applicable cellular system, and/or any number of different wireline or wireless networking techniques, comprising but not limited to Wi-Fi, wireless local access network, WLAN, techniques such as Institute of Electrical and Electronics Engineers, IEEE, 802.11, 802.16, and/or the like. In addition, these signals may include speech data, user generated data, user requested data, and/or the like. In this regard, the apparatus may be capable of operating with one or more air interface standards, communication protocols, modulation types, access types, and/or the like. More particularly, the apparatus may be capable of operating in accordance with various first generation, 1G, second generation, 2G, 2.5G, third-generation, 3G, communication protocols, fourth-generation, 4G, communication protocols, Internet

Protocol Multimedia Subsystem, IMS, communication protocols, for example, session initiation protocol, SIP, and/or the like. For example, the apparatus may be capable of operating in accordance with 2G wireless communication protocols IS- 136, Time Division Multiple Access TDMA, Global System for Mobile communications, GSM, IS-95, Code Division Multiple Access, CDMA, and/or the like. Also, for example, the mobile terminal may be capable of operating in accordance with 2.5G wireless communication protocols General Packet Radio Service. GPRS, Enhanced Data GSM Environment, EDGE, and/or the like. Further, for example, the apparatus may be capable of operating in accordance with 3G wireless communication protocols such as Universal Mobile Telecommunications System, UMTS, Code Division Multiple Access 2000, CDMA2000, Wideband Code Division Multiple Access, WCDMA, Time Division-Synchronous Code Division Multiple Access, TD-SCDMA, and/or the like. The apparatus may be additionally capable of operating in accordance with 3.9G wireless communication protocols such as Long Term Evolution, LTE, or Evolved Universal Terrestrial Radio Access Network, E-UTRAN, and/or the like. Additionally, for example, the apparatus may be capable of operating in accordance with fourth-generation, 4G, wireless communication protocols such as LTE Advanced and/or the like as well as similar wireless communication protocols that may be developed in the future.

[0057] Some Narrow-band Advanced Mobile Phone System, NAMPS, as well as Total Access Communication System, TACS, mobile terminal apparatuses may also benefit from embodiments of this invention, as should dual or higher mode phone apparatuses, for example, digital/analog or TDMA/CDMA/analog phones. Additionally, apparatus 10 may be capable of operating according to Wi-Fi or Worldwide Interoperability for Microwave Access, WiMAX, protocols.

[0058] It is understood that the processor 20 may comprise circuitry for implementing audio/video and logic functions of apparatus 10. For example, the processor 20 may comprise a digital signal processor device, a microprocessor device, an analog-to-digital converter, a digital- to-analog converter, and/or the like. Control and signal processing functions of the mobile terminal may be allocated between these devices according to their respective capabilities. The processor may additionally comprise an internal voice coder, VC, 20a, an internal data modem, DM, 20b, and/or the like. Further, the processor may comprise functionality to operate one or more software programs, which may be stored in memory. In general, processor 20 and stored software instructions may be configured to cause apparatus 10 to perform actions. For example, processor 20 may be capable of operating a connectivity program, such as a web browser. The connectivity program may allow the mobile terminal 10 to transmit and receive web content, such as location-based content, according to a protocol, such as wireless application protocol, WAP, hypertext transfer protocol, HTTP, and/or the like

[0059] Apparatus 10 may also comprise a user interface including, for example, an earphone or speaker 24, a ringer 22, a microphone 26, a display 28, a user input interface, and/or the like, which may be operationally coupled to the processor 20. In this regard, the processor 20 may comprise user interface circuitry configured to control at least some functions of one or more elements of the user interface, such as, for example, the speaker 24, the ringer 22, the microphone 26, the display 28, and/or the like. The processor 20 and/or user interface circuitry comprising the processor 20 may be configured to control one or more functions of one or more elements of the user interface through computer program instructions, for example, software and/or firmware, stored on a memory accessible to the processor 20, for example, volatile memory 40, non-volatile memory 42, and/or the like. Although not shown, the apparatus may comprise a battery for powering various circuits related to the mobile terminal, for example, a circuit to provide mechanical vibration as a detectable output. The user input interface may comprise devices allowing the apparatus to receive data, such as a keypad 30, a touch display, which is not shown, a joystick, which is not shown, and/or at least one other input device. In embodiments including a keypad, the keypad may comprise numeric 0-9 and related keys, and/or other keys for operating the apparatus.

[0060] As shown in FIG. 2, apparatus 10 may also include one or more means for sharing and/or obtaining data. For example, the apparatus may comprise a short-range radio frequency, RF, transceiver and/or interrogator 64 so data may be shared with and/or obtained from electronic devices in accordance with RF techniques. The apparatus may comprise other short-range transceivers, such as, for example, an infrared, IR, transceiver 66, a Bluetooth™' BT, transceiver 68 operating using Bluetooth™ brand wireless technology developed by the

Bluetooth™ Special Interest Group, a wireless universal serial bus, USB, transceiver 70 and/or the like. The Bluetooth™ transceiver 68 may be capable of operating according to low power or ultra-low power Bluetooth™ technology, for example, Wibree™, radio standards. In this regard, the apparatus 10 and, in particular, the short-range transceiver may be capable of transmitting data to and/or receiving data from electronic devices within a proximity of the apparatus, such as within 10 meters, for example. Although not shown, the apparatus may be capable of transmitting and/or receiving data from electronic devices according to various wireless networking techniques, including 6LoWpan, Wi-Fi, Wi-Fi low power, WLAN techniques such as IEEE 802.11 techniques, IEEE 802.15 techniques, IEEE 802.16 techniques, and/or the like.

[0061] The apparatus 10 may comprise memory, such as a subscriber identity module, SIM, 38, a removable user identity module, R-UIM, and/or the like, which may store information elements related to a mobile subscriber. In addition to the SIM, the apparatus may comprise other removable and/or fixed memory. The apparatus 10 may include volatile memory 40 and/or non-volatile memory 42. For example, volatile memory 40 may include Random Access Memory, RAM, including dynamic and/or static RAM, on-chip or off-chip cache memory, and/or the like. Non-volatile memory 42, which may be embedded and/or removable, may include, for example, read-only memory, flash memory, magnetic storage devices, for example, hard disks, floppy disk drives, magnetic tape, etc., optical disc drives and/or media, non-volatile random access memory, NVRAM, and/or the like. Like volatile memory 40 non-volatile memory 42 may include a cache area for temporary storage of data. At least part of the volatile and/or non- volatile memory may be embedded in processor 20. The memories may store one or more software programs, instructions, pieces of information, data, and/or the like which may be used by the apparatus for performing functions of the mobile terminal. For example, the memories may comprise an identifier, such as an international mobile equipment identification, IMEI, code, capable of uniquely identifying apparatus 10.

[0062] Without in any way limiting the scope, interpretation, or application of the claims appearing below, a technical effect of one or more of the example embodiments disclosed herein is that re-establishments may proceed faster. Another technical effect of one or more of the example embodiments disclosed herein is that re-establishments may succeed more often.

[0063] Embodiments of the present invention may be implemented in software, hardware, application logic or a combination of software, hardware and application logic. The software, application logic and/or hardware may reside on memory, the processor or electronic components, for example. In an example embodiment, the application logic, software or an instruction set is maintained on any one of various conventional computer-readable media. In the context of this document, a "computer-readable medium" may be any media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer, with one example of a computer described and depicted in FIGURE 2. A computer-readable medium may comprise a computer-readable non-transitory storage medium that may be any media or means that can contain or store the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. The scope of the invention comprises computer programs configured to cause methods according to embodiments of the invention to be performed.

[0064] If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the above-described functions may be optional or may be combined.

[0065] Although various aspects of the invention are set out in the independent claims, other aspects of the invention comprise other combinations of features from the described embodiments and/or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims.

[0066] It is also noted herein that while the above describes example embodiments of the invention, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications which may be made without departing from the scope of the present invention as defined in the appended claims.

Claims

WHAT IS CLAIMED IS

1. An apparatus, comprising:

a receiver configured to receive a first credential associated with a user equipment;

the receiver further configured to receive a connection re- establishment request from the user equipment;

at least one processing core configured to compare a second credential received from the user equipment to the first credential; and

responsive to the first credential matching the second credential, the at least one processing core is configured to accept the connection re-establishment request.

2. An apparatus according to claim 1 , wherein the apparatus is configured to act as an access point between the user equipment and a cellular base station.

3. An apparatus according to claim 1 or 2, wherein the apparatus is configured to receive the second credential in the connection re-establishment request.

4. An apparatus according to claim 2 or 3, wherein the first credential is received from the cellular base station.

5. An apparatus according to claim 4, wherein the first credential is comprised in a message comprised in a context setup procedure.

6. An apparatus according to any preceding claim, wherein accepting the connection re- establishment request comprises causing a connection re-establishment message to be transmitted to the user equipment.

7. An apparatus according to any preceding claim, wherein the apparatus is further configured to participate in a local authentication procedure with the user equipment.

8. An apparatus according to any of claims 2 - 7, wherein the apparatus is configured to convey cellular security procedure-related messags between the cellular base station and the user equipment without participating in the cellular security procedures.

9. An apparatus according to any preceding claim, wherein the first credential and the second credential comprise message authentication codes for integrity.

10. A method, comprising:

receiving a first credential associated with a user equipment;

receiving a connection re-establishment request from the user equipment;

comparing a second credential received from the user equipment to the first credential; and

responsive to the first credential matching the second credential, accepting the connection re-establishment request.

11. A method according to claim 10, further comprising operating an apparatus as an access point between the user equipment and a cellular base station.

12. A method according to claim 10 or 11, further comprising receiving the second credential in the connection re-establishment request.

13. A method according to claim 11 or 12, wherein the first credential is received from the cellular base station.

14. A method according to claim 13, wherein the first credential is comprised in a message comprised in a context setup procedure.

15. A method according to any of claims 10 - 14 wherein accepting the connection re- establishment request comprises causing a connection re-establishment message to be transmitted to the user equipment.

16. A method according to any of claims 10 - 15, further comprising participating in a local authentication procedure with the user equipment.

17. A method according to any of claims 11 - 16, further comprising conveying cellular security procedure-related messags between the cellular base station and the user equipment without participating in the cellular security procedures.

18. A method according to any preceding claim, wherein the first credential and the second credential comprise message authentication codes for integrity.

19. An apparatus, comprising:

at least one processor; and

at least one memory including computer program code

the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following:

detect that a radio link failure has occurred between the apparatus and an access point providing, for the apparatus, access to a cellular base station, and

responsive to detecting the radio link failure, transmit a connection re- establishment request to the access point, the connection re-establishment request comprising a first credential and a local connection identity valid between the apparatus and the access point.

20. An apparatus according to claim 19, wherein the first credential comprises a message authentication code for integrity

21. A method, comprising:

detecting that a radio link failure has occurred between the apparatus and an access point providing, for the apparatus, access to a cellular base station, and responsive to detecting the radio link failure, transmitting a connection re-establishment request to the access point, the connection re-establishment request comprising a first credential and a local connection identity valid between the apparatus and the access point.

22. A method according to claim 21, wherein the first credential comprises a message authentication code for integrity.

23. A computer program configured to cause a method according to at least one of claims 10 - 18 or 21 - 22 to be performed, when run.