GB2511540A

GB2511540A - Wireless communication system and method

Info

Publication number: GB2511540A
Application number: GB1304034.0A
Authority: GB
Inventors: Marko Akselin; Toni Tirkkonen; Matti Moisanen
Original assignee: Broadcom Corp
Current assignee: Broadcom International Ltd; Broadcom Corp
Priority date: 2013-03-06
Filing date: 2013-03-06
Publication date: 2014-09-10
Anticipated expiration: 2033-03-06
Also published as: GB2511540B; GB201304034D0

Abstract

Embodiments of the invention provide methods, apparatuses and computer programs arranged to control access to resources of a communication network by a user equipment. One embodiment comprises a user equipment comprising an apparatus for use in controlling access to resources of a communication network, the communication network comprising a Packet-Switched (PS) network comprising aplurality of eNodeBs and a Circuit-Switched (CS) network comprising a plurality of base stations (BS), each said base station being associated with a location area (LA), the apparatus being capable of receiving a CS service via the CS network and being associated with a said location area whilst being served by a said eNod.cB, wherein, responsive to receiving a mobile terminated CS service notification, the user equipment is configured to change cell association to a said base station, the apparatus comprising a processing system arranged to cause the apparatus to: allocate processing resources for use in establishment of a mobile terminated CS service corresponding to the received notification; and responsive to receipt of a release message following receipt of a location area accept message, said release message being indicative of failure to provision said mobile terminated CS service, maintain said allocation of the processing resources and monitor for a service setup message from the CS network, whereby to enable establishment of said mobile terminated CS service.

Description

WIRELESS COMMUNICATION SYSTEM AND METHOD

Technical Field

The present invention relates to wireless communication systems, methods, devices and computer programs, and more specifically relates to controlling access to resources of a communication network by a user equipment. Embodiments provide a mechanism for controlling access to resources of a Base Station (BS) in response to a change in cell association.

Background

The following meanings for the abbreviations used in this specification apply: BS Base Station CN core network CS circuit switched CSFB circuit switched fallback CSMT Circuit Switched fallback Mobile Terminated call FOR Follow-On-Request E-UTRAN Enhanced Universal Terrestrial Radio Access Network eNB enhanced node B eNodeB enhanced node B GERAN GSM EDGE Radio Access Network GSM Global System for Mobile Communications IMS IP Multimedia System LA location area LAC location area code LAU location area update LIE Long Term Evolution LIE-A LTE Advanced MME mobility management entity MTRF Mobile Terminating Roaming Forwarding MTRR Mobile Terminating Roaming Retry MSC mobile switching ccntrc NW Network PLMIN public land mobile network PS packet switched RAT radio access technology RNC radio network controller RRC radio resource control SAE System Architecture Evolution SI System Information SIB Systcm Information Block SMS short message service UE user equipment UMTS Universal Mobile Telecommunications System UTRAN Universal Terrestrial Radio Access Network Long Term Evolution (LTE) and/or LTE Advanced (LTE-A) networks support Packet-Switched (PS) data transport, and all services, including voice telephony services, must be supported via a PS core network. LTE networks may be configured to provision Circuit-Switched (CS) services, such as voice telephony services, via a CS network, such as Global System for Mobile communications (GSM) and/or Universal Mobile Telecommunications System (UMTS); this process is widely known as Circuit Switched Fallbaek (CSFB). The LTE and LTE-A networks will generally be referred to herein as packet-switched (PS) network.

In particular, CSFB utilises a CS network configured for provisioning CS services. The CS network may, for example, comprise a GSM and/or a IJMTS network. Responsive to registration, a user equipment (UE) is registered in both the PS network and the CS network and is associated with a location area code associated with a CN entity, such as a Mobile Switching Centre, responsible for provisioning CS services thereto. Subsequently, any mobile terminated CS services for the UE are routed via the CN entity. In response to receiving a mobile terminated CS service, the CN entity may transmit a paging notification to the UE, which may then change cell association to a base station (BS) in the CS network to receive the CS service. The change of cell association may be via a handover or a redirection process. It will be noted that the UE may avail some CS services, such as short message service (SMS), without having to change cell association to a base station in the CS network.

If upon changing cell association, the liE is associated with a different location area (LA) than the one associated with it during registration (or in a subsequent location update), i.e. the liE is being served by a different CN entity of the CS network, the UE may additionally perform a location area update (LAU) process to receive CS services via the CN entity of the CS network it is currently attached to.

In this case, the liE may set a Circuit Switched fallbaek Mobile Terminated call (CSMT) flag in a LAU request message to indicate that there is an impending mobile terminated CS service and send to the CN entity it is currently attached to, which may then cause the mobile terminated CS service to be routed via it. The process of transfer of impending mobile terminated CS services between CN entities is referred to as Mobile Terminating Roaming Retry (MTRR) or Mobile Terminating Roaming Forwarding (MTRF).

In some non-3GPP standard compliant implementations of MTRR and the MTRF, the inventors have identified the UE may untimely receive a release message instructing it to release radio resources prior to establishment of the impending mobile terminated CS service, thereby causing dropouts.

In addition to the CSMT flag, the UE may additionally set a Follow-On-Request (FOR) flag in order to indicate to the CS network that the liE has a further mobile originated CS service request. For example, if the LIE had initiated a mobile originated SMS request before it changed cell association to a base station in the CS network to receive a mobile terminated CS service, the LIE may set both the CSMT and the FOR flags. Usage of the FOR flag in conjunction with the CSMT flags leads to a high service dropout rates because the CS network may prioritise the mobile originated CS service over the mobile terminated CS service, thereby causing dropout of a mobile terminated CS service.

Some embodiments are directed towards providing an improved mobile term inatcd CS service setup.

Summary

In a first exemplary embodiment of the invention there is provided a user equipment comprising an apparatus for use in controlling access to resources of a communication network, the communication network comprising a Packet-Switched (PS) network comprising a plurality of eNodeBs and a Circuit-Switched (CS) network comprising a plurality of base stations (BS), each said base station being associated with a location area (LA), the apparatus being capable of receiving a CS service via the CS network and being associated with a said location area whilst being served by a said cNodcB, wherein, responsive to receiving a mobile terminated CS service notification, the user equipment is configured to change cell association to a said base station, the apparatus comprising a processing system arranged to cause the apparatus to: allocate processing resources for use in establishment of a mobile terminated CS service corresponding to the received notification; and responsive to receipt of a release message following receipt of a location area accept message, said release message being indicative of failure to provision said mobile terminated CS service, maintain said allocation of the processing resources and monitor for a service setup message from the CS network, whereby to enable establishment of said mobile terminated CS service.

In a second exemplary embodiment of the invention there is provided a method of controlling access to resources of a communication network by a user equipment, the communication network comprising a Packet-Switched (PS) network comprising a plurality of eNodeBs and a Circuit-Switched (CS) network comprising a plurality of base stations (BS), each said base station being associated with a location area (LA), the user equipment being capable of receiving a CS service via the CS network and being associated with a said location area whilst being served by a said eNodeB, wherein, responsive to receiving a mobile terminated CS service notification, the user equipment is configured to change cell association to a said base station, the method comprising: allocating processing resources for use in establishment of a mobile terminated CS service corresponding to the received notification; responsive to receipt of a release message following receipt of a location area accept message, said release message being indicative of failure to provision said mobilc tcrminatcd CS scrvicc, maintaining said allocation of thc proccssing rcsourccs; and monitoring for a service setup message, whereby to enable establishment of said mobile terminated CS service.

The first and second exemplary embodiments are most conveniently implemented in a user equipment. Some embodiments also include a computer program comprising a sct of instructions, which, when cxccutcd by a uscr cquipmcnt, cause the user equipment to perform a method according to the second embodiment.

In a third exemplary embodiment of the invention there is provided a user cquipmcnt comprising an apparatus for usc in controlling acccss to rcsourccs of a communication nctwork, thc communication nctwork comprising a Packct-Switchcd (PS) network comprising a plurality of eNodeBs and a Circuit-Switched (CS) network comprising a plurality of base stations (BS), each said base station being associated with a Location Area (LA), the apparatus being capable of receiving a CS service via thc CS nctwork and bcing associatcd with a first location arca whilst bcing scrvcd by a said eNodeB, wherein, responsive to receiving a mobile terminated CS service notification, the user equipment is configured to change cell association to a said base station, the base station being associated with a second location area, the apparatus comprising a proccssing systcm arranged to causc thc apparatus to pcrform a Location Area Update (LAU) process in the event that the first location area is different to the second location area, the Location Area Update process comprising the steps of transmitting a LAU request message for receipt by a core network entity in the CS network comprising data indicative of the second location area; and responsive to receipt of a LAU process message indicative of a processing state associated with the LAU process from the core network entity, transmitting a response message after a prcdctcrmincd pcriod of timc following rcccipt of said LAU process mcssagc.

In a fourth cxcmplary cmbodimcnt of thc invcntion thcrc is providcd a mcthod of controlling access to resources of a communication network by a user equipment, the communication network comprising a Packet-Switched (PS) network comprising a plurality of cNodcBs and a Circuit-Switched (CS) network comprising a plurality of basc stations (BS), cach said basc station bcing associatcd with a location arca (LA), the apparatus being capable of receiving a CS service via the CS network and being associated with a first location area whilst being served by a said eNodeB, wherein, responsive to receiving a mobile terminated CS service notification, the user equipment is configured to change cell association to a said base station, the base stationbeing associated with a second location area, the method comprising performing a Location Area Update (LAU) process in the event that the first location area is different to the second location area, the Location Area Update process comprising the steps of: transmitting a LAU request message for receipt by a core network entity in the CS network comprising data indicative of the second location area; and responsive to receipt of a LAU process message indicative of a processing state associated with the LAU process from the core network entity, transmitting a response message after a predetermined period of time following receipt of said LAU process message.

The third and fourth exemplary embodiments are most conveniently implemented in a user equipment. Some embodiments also include a computer program comprising a set of instructions, which, when executed by a user equipment, cause the user equipment to perform a method according to the fourth embodiment.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, given by way of example only, which is made with reference to the accompanying drawings.

Brief Description of the DrawinQs

Figure 1 is a simplified block diagram of a communication network within which some embodiments operate.

Figure 2 is a logic flow diagram that illustrates the operation of a method, and a result of execution of computer program instructions embodied on a computer readable memory, from the perspective of a user equipment, according to some embodiments.

Figure 3 is a flow diagram that illustrates the various steps performed by user equipment, packet-switched network elements and circuit-switched network elements according to some embodiments.

Figure 4 is a logic flow diagram that illustrates the operation of a method, and a result of execution of computer program instructions embodied on a computer readable memory, from the perspective of a user equipment, according to some embodiments.

Figure 5 is a flow diagram that illustrates the various steps performed by user equipment, packet-switched network elements and circuit-switched network elements according to some embodiments.

Figure 6 is a simplified block diagram of various network devices, which are exemplary electronic devices suitable for use in practicing some example embodiments.

Detailed Description

In the following, examples and embodiments of the present invention are described with reference to the drawings. For illustrating the present invention, the examples and embodiments will be described in connection with a cellular communication network based on a 3GPP-type cellular system, such as Long Term Evolution (LTE) and/or LTE Advanced (LTE-A) network. However, it is to be noted that the present invention is not limited to an application using such types of communication system, but is also applicable in other types of communication systems and the like.

Embodiments are concerned with improving setup of mobile terminated circuit-switched (CS) services, and in particular with systems in which a user equipment (UE) changes or is directed to change cell association from a cell in a packet-switched (PS) network, such as LTE and/or LTE-A network, to a CS network, such as Global System for Mobile communications (GSM) and/or Universal Mobile Telecommunications System (UMTS), to receive a mobile terminated CS service, such as voice telephony service. This process is widely known as Circuit Switched Fallback (CSFB).

A basic system architecture of a communication network where some examples of embodiments of the invention are applicable may comprise a commonly known architecture of one or more communication networks comprising a wired or wireless access network subsystem and a core network. An exemplary communication network, which includes a PS network, such as LTE and/or LTE-A network, working in conjunction with a CS network, such as GSM and/or UMTS, to provision at least CS services to liEs, will now be described with reference to Figure 1.

The communication network 100 may comprise a PS network 110, which comprises a core network (CN) and a radio access network (RAN). The CN comprises at least one core network element, such as mobility management entity (MME) 111, and the RAN comprises at least an eNodcB 113, which provides radio connectivity to liEs. The PS network 100 may, for example, comprise a LTE and/or LTE-A network.

The communication network 100 further comprises a CS network 120 comprising a CN and a RAN. The CN of the CS network comprises at least a first CN entity 125 and a second 04 entity 121. The first and second CN entities 125 and 121 may, for example, comprise a mobile switching centre (MSC) and/or visitor location register (VLR) (not shown), and may be linked to each other via a control link, such as an SI link, in order to facilitate mobility management. The RAN of the CS network comprises at least a first and a second base station (BS) 127 and 123 for providing radio connectivity to UEs. Some of the CN elements of the CS and the PS networks and 110 may be linked via an SGs link in order to facilitate provisioning of CS services to liEs. As is well known in the art, the SGs link enables communication between the CN network entities of the CS and the PS networks for usc in mobility management and paging procedures.

The liE 50 or another wireless transmit/receive device having a similar function, such as a modem chipset, a chip, a module etc., which can also be part of a UE attached as a separate element to a UE, is able to communicate with a cell, such as the eNodeB 113, the first base station 127 and the second base station 123, via one or more channels for transmitting several types of data. The tiE 50 may, for example, comprise a mobile phone, a smartphone and/or a portable computer, such as a tablet computer, a portable digital assistant, a laptop computer and/or a notebook computer.

The communication network 100 may additionally be in communication with various mobility management entities (not shown), which facilitate mobility of UEs across various carriers, and/or network management entities, which manage resources of the communication network.

The general frmnctions and interconnections of the described elements, which also depend on the actual network type, are known to those skilled in the art and described in corresponding specifications, so that a detailed description thereof is omitted herein. However, it is to be noted that several additional network elements and sialling links may be employed for a communication connection to or from UEs, eNodeBs, base stations or CN elements, besides those described in detail herein below.

The UE SO may be configured to operate in accordance with aspects of CSFB as set out in 3GPP TS 23.272 V10.4.0, entitled "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; CS fallback (CSFB) in Evolved Packet System (EPS); Stage 2 (Release 10)", the contents of which arc incorporatcd herein by reference. In particular, when attaching to the PS network 110, the liE may indicate that it is configured to use CSFB. The CN entity of the PS network 110, such as the MME 111, then causes the UE 50 to be registered with the CS network 120 for receiving CS services and the PS network 110 for receiving PS services. In this ease, the UE 50, whilst being served by an eNodeB, such as the eNodeB 113, may be associated with a first location area (LA), specifically location area code (LAC), associated with the first CN entity 125 of the CS network 120 that is responsible for provisioning CS services to the liE 50. The first N entity 125 in the CS network 120 maybe selected for serving the liE SOon the basis of for example, a location of the UE 50.

Referring to Figures 2 and 3, in accordance with conventional systems and subsequent to registration, a mobile terminated CS service may be routed to the first CN entity 125, which may notify the liE 50 via the PS network 110 (S301 & S303).

The UE 50 may then transmit an extended service request (S305) to the N entity, such as the MME 111, of the PS network 110 associated with the liE 50. The MME 111 may then cause the FE 50 to change cell association to a base station in the CS network 120 and be served by a CN entity in the CS network 120 (S307). The IJE 50 may alternatively change cell association to a base station in the CS network of its own accord. The change of cell association may be via a handover or a redirection process.

The liE 50 may allocate processing resources for establishment of the mobile terminated CS service (S201). The allocated processing resources may alternatively or additionally comprise memory resources of the UE 50, and!or resources that are intrinsic to thc UE 50. Thc liE 50, thc second base station 123 and/or the second CN entity 121 may additionally allocate network resources, such as radio resources for a CS radio connection, for establishment and/or subsequent provisioning of the mobile terminated CS service.

The CN and RAN elements of the CS network 120 for serving the HE 50 may be selected on the basis ot for example, a location of the UE 50, and as a consequence the liE 50 may be associated with the second 04 entity 121 and the second base station 123 associated with the second CN entity 121. The second CN entity 121 may be associated with a second location area, which may be different from the first location area.

When the first location area is different to the second location area, the UE 50 may be arranged to perform a LAIJ process, whereby to receive the aforementioned mobile terminated CS service via the second CN entity 121. The LAIJ process may comprisc transmitting a LAU request mcssagc to thc second CN entity 121 to rcgister a change in its association in order to cause provisioning of a further mobile terminated CS service via the second CN entity 121. The LAU request may comprise data indicative of the second location area (S309). The UE 50 may additionally set a Circuit Switched faliback Mobile Terminated call (CSMT) flag in the LAIJ request message in order to indicate to the second CN entity 121 that there is an impending mobile terminated CS service. In response to receiving the LAU request message, the second CN entity 121 may communicate with the first CN entity 125 and/or a further CN entity, such as a home location register, of the CS network 120 to register the curreiitporntofattachmentoftheUE 50 in the CS network 120 (S311).

Responsive to registering the current point of attachment of the liE 50, the second CN entity 121 may transmit a LAU acccpt mcssage (S3 13), thcrcby indicating to the UE 50 that the change to its point of association in thc CS network 120 has been registered and that any subsequellt mobile terminated CS services may be provisioned to the liE 50 via the second CN entity 121. In response to receiving the LAU accept message the UE 50 may transmit a TMSI reallocation complete message to the second CN entity 121, thereby acknowledging receipt of the LAIJ accept message (S3 15). The second CN entity 121 may additionally cause the impending mobile terminated CS service to be routed thereto for provisioning to the TJE 50.

In conventional systems, if the UIE 50 subsequently receives a radio resource (RR) connection release message (hereinafter referred to as release message'), for example following receipt of the LAU accept message (S3 17), the UE 50 releases the allocated network and processing resources, thereby aborting establishment of the impending mobile terminated CS service. As is well known in the art, release messages instruct LiEs to release network resources set aside for establishment of an impending mobile terminated CS service.

In some example non-3GPP standard compliant networks, the inventors have identified that a release message may be received by the LiE 50 prior to establishment of the impending mobile terminated CS service, thereby causing dropouts when in fact a CS radio connection for establishment of the impending mobile terminated CS service could be re-established. In addition, LAU requests that have both the CSMT and a Follow-On-Request (FOR) flags set, which indicate to the CS network 120 that the UE 50 has a ifirther mobile originating CS service request, tend to be error prone and may be lead to erroneous transmission of a release message.

Accordingly, embodiments provide arrangements in which the LiE 50 is configured to maintain allocation of the aforementioned processing resources and monitor for receipt of a service setup message in response to receiving the release message following receipt of the LAU accept message, whereby to cause establishment of the impending mobile terminated CS service (S203 & S317). In effect, the UE 50 may release network resources set aside for the establishment of the impending mobile terminated CS service, but maintains allocation of the processing resources reserved therefor and monitors for receipt of the service setup message.

By maintaining allocation of the processing resources the LiE 50 may prevent the impending mobile terminated CS service from being dropped for example in cases where radio resources could be re-allocated by, for example, establishing a further CS radio connection. That being the case, some embodiments enhance the user experience by reducing CS service dropouts in CSFB-compliant networks.

Furthermore, embodiments reduce delays that would have otherwise occurred due to re-initiation of the mobile terminated CS service.

In at least some arrangements, in response to receiving the release message, the UE 50 may transmit a paging response message to the second CN entity 121, whereby to cause receipt of the aforementioned service setup message (S319). In particular, the paging response message causes the second CN entity 121 to allocate further network resources, which may, for example, include establishing a further CS radio connection, for use in establishment of the impending mobile terminated CS service. In particular, in response to receiving the paging response message, the second CN entity 121 may allocate further radio resources for establishment of the impending mobile terminated CS service and attempt provisioning it to the UE 50.

Thus, by transmitting the paging response message, the liE 50 prevents the impending mobile terminated CS service from being dropped.

In conventional systems, establishment of the impending mobile terminated CS service may have been considered to have been aborted at the equivalent of step S317, i.e. upon reception of the release message. By contrast, in at least some arrangements, the UE 50 advantageously causes the second CN entity 121 to resume establishment of the impending mobile terminated CS service.

In conventional systems, UEs are configured to transmit a paging response message only if a LAU request message at the equivalent of step S309 has not been transmitted. By contrast, the embodiments advantageously combine use of the paging response message and the LAU request message to resume establishment of impending mobile terminated CS service which would have otherwise been dropped at the equivalent of step S317.

As described above, the liE 50 may receive the release message prior to conclusion of the process to establishment of the impending mobile terminated CS service. In conventional systems, the liE 50 responsively releases the CS radio connection reserved for establishment of the impending mobile terminated CS service and considers the establishment thereof to have been aborted. However, establishment of the impending mobile terminated CS service may not have been aborted by the second CN entity 121, which may subsequently attempt to provision it to the liE 50.

Nevertheless, and because the UE 50 assumes that establishment of the impending mobile terminated CS service has been terminated at step S317, the UE 50 releases the aforementioned processing resources.

Furthermore, as is well known in the art, liEs are configured to periodically evaluate coverage of neighbouring cells and change cell association to a cell providing bcttcr covcragc. That bcing thc casc, thc UE 50 may pcrform such an evaluation of neighbouring cells in response to receiving the release message at step 5317 and change cell association in dependence thereof In this case, the impending mobile terminated CS service may have to be dropped regardless of whether network resources for establishment thereof could have been re-allocated because the change of ccli association may trigger further location updates.

By contrast, according to some embodiments the UE 50 may configure a timer for a predetermined period of time (hereinafter referred to as update timer'), and maintain allocation of the processing resources set aside for establishment of the impcnding mobile tcrminatcd CS scrvicc and monitor for receipt of thc aforementioned service setup message for at least the duration of the update timer. In effect, the IJE 50 may be configured to release the aforementioned network resources in response to receiving the release message, but maintain allocation of the processing resources for at least the duration of the update timer. This enables the impending mobile terminated service to be provisioned if the second CN entity 121 resumes establishment thereof of its own accord and/or responsive to receiving the aforementioned paging response message.

In at least some arrangements, the update timer may be used in conjunction with the aforementioned paging response message. In this case, the update timer may be configured in response to transmission of the paging response message (5319) and! or the UE 50 may be configured to transmit the paging response message prior to expiry of the update timer.

Additionally or altematively, the update timer may be configured in response to: allocation of the aforementioned processing resources (S201), allocation of the aforementioned network resources for establishment of the impending mobile terminated CS service, transmission of the aforementioned LAU request message (S309), reception of the aforementioned LAU accept message (S313), transmission of the aforementioned TMSI reallocation message (5315) and/or reception of the aforementioned release message (S317).

As described above, in conventional arrangements, reception of the release message at step S317 may cause the UE 50 to evaluate and! or change its cell association, which may lead to dropouts. In particular, subsequent to receiving the release message, the TIE may compare coverage of neighbouring cells and change its association to a cell with better coverage. By contrast, in at least some embodiments, the UE 50 may be configured to prevent evaluation of coverage of neighbouring cells or ignore any such previous evaluations for the duration of the update timer.

Alternatively or additionally, the TIE 50 may be configured to process a trigger to change ccli association, which may, for example, be generated on the basis of such an evaluation, on the basis of at least one predetermined rule prior to expiry of the update timer. If, for example, the TIE 50 initiates or is directed by a network element to change its association to a different ccli before the expiry of the update timer, the impending mobile terminated CS service may havc to be droppcd becausc handovers may cause further delays and/or trigger further location updates.

Accordingly, the predetermined rule may comprise maintaining an association with a base station the liE 50 is currently attached to if it is within its coverage area, thereby preventing further location updates. The predetermined rule may additionally or alternatively comprise establishing cell association with a base station associated with the aforementioned second location area, thereby preventing further re-routing of the impending mobile terminated CS service via a further CN entity of the CS network 120. The predetermined rule may additionally or alternatively comprise performing an intra-RAT change of cell association if an inter-RAT change of cell association is not feasible, thereby preventing the impending mobile terminated CS service from being dropped because it may not possible to transfer it to a different RAT.

Subsequent to successfully concluding the LATJ procedure or in response to receiving the aforementioned paging response message, the second CN entity 121 may cause establishment of the impending mobile terminated CS service as will now be explained with further reference to Figure 3. The second CN entity 121 may communicate with first N entity 125 and/or a flirther CN entity to cause establishment and provisioning of the impending mobile terminated CS service via the second CN entity 121 (S321). The second CN entity 121 may then transmit the aforementioned service setup message, which may comprise a setup message and/or a service confirmation message, to the UE 50 (S323), and the TIE 50 may accept to receive the mobile terminated CS service by transmitting a confirmation message, which may comprise a call confirmed message (S325). In the event that the second CN entity 121 transmits a paging request at the equivalent of step S323, the UE 50 may then transmit a further or a first paging response message at the equivalent of step S325.

Referring to Figures 4 and 5, in accordance with an alternative embodiment, and subsequent to transmission of the aforementioned [AU accept message (S309), the UE 50 may take particular actions in dependence on data received from the CS network. For example, responsive to receipt of a LAU process message, which may, for example, comprise the aforementioned [AU accept message (5313), indicative of a processing state associated with the LAU process from the second CN entity 121, the UE 50 may transmit a response message (hereinafter referred to as LAU response message') after a predetermined period of time (hereinafter referred to as response timer') following receipt of the [AU process message (5401 & S603).

In conventional systems, CN entities may ignore the aforementioned CSMT flag, resulting in an impending mobile terminated CS service to be routed to the mobile device. In such cases, the second CN entity 121 may transmit a LAU accept message indicating successful completion of location update and release the aforementioned network resources without causing the impending mobile terminated CS service to be provisioned to the TiE 50. However, the second CN entity 121 may later attempt provisioning the aforementioned mobile terminated CS service of its own accord, and/or in response to receiving the aforementioned paging response message and/or a further control message received from a further CN entity, such as a Gateway MSC, but such provisioning attempt may fail because, as described above, the UE 50 may change cell association subsequent to releasing the network resources.

Accordingly, embodiments may prolong the LAU process by introducing a delay, thereby providing extra time to the CS network 120 for provisioning the impending mobile terminated CS service. Thus, embodiments reduce likelihood of the mobile terminated CS service from being dropped by providing extra processing time to the second CN entity 121.

As described above, the [AU process message may comprise the aforementioned LAU accept message (S313), in which case the LAU response message may comprise the aforementioned TMSI reallocation message (S315).

Additionally or alternatively, the LAU process message may comprise an identity request, and the LAU response message may comprise an identity corresponding to the liE 50. Additionally or alternatively, the LAU process message may comprise an authentication challenge, and the LAU response message may comprise an authentication response. Accordingly, embodiments enable the aforementioned delay to be introduced at any stage of the LAU process involving a message exchange between the second CN entity 121 and the liE 50.

In at least some arrangements, the liE 50 may generate one or more Protocol Data Units (PDU) corresponding to the LAU response message following receipt of the LAU process message, and be configured to intercept the generated PDUs at, for example, a Mobility Management (MM) layer. The PDUs may alternatively be intercepted at, for example, a Radio Resource Management (RRM) layer. The UE 50 may then transmit the intercepted PDUs to the second CN entity 121 in response to passage of the response timer following interception of the PDUs, thereby introducing the aforementioned delay.

Figures 2 and 4 represent results from executing a computer program or an implementing algorithm stored in the local memory of the liE 50 as well as illustrating the operation of a method and a specific manner in which the processor and memory with computer program/algorithm are configured to cause the liE 50 (or one or more components thereof) to operate. The various blocks shown in these Figures may also be considered as a plurality of coupled logic circuit elements constructed to carry out the associated function(s), or specific result or function of strings of computer program code stored in a computer readable memory. Such blocks and the functions they represent are non-limiting examples, and may be practiced in various components such as integrated circuit chips and modules, and that the exemplary embodiments of this invention may be realized in an apparatus that is embodied as an integrated circuit. The integrated circuit, or circuits, may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor or data processors, a digital signal processor or processors, bascband circuitry and radio frequency circuitry that are configurable so as to operate in accordance with the exemplary embodiments of this invention.

Reference is now made to Figure 6 for illustrating a simplified block diagram of various electronic devices and apparatus that are suitable for use in practicing the exemplary embodiments of this invention. In Figure 6 an eNodeB 113 and a second base station 123 is adapted for communication over a wireless link with a liE 50, such as a mobile terminal. The eNodeB 113 and/or the second base station 123 may be a macro Node B, a remote radio head or relay station, or other type of base station/cellular network access node.

The UE 50 includes processing means such as at least one data processor (DP) SOA, storing means such as at least one computer-readable memory (MEM) SOB storing at least one computer program (PROG) SOC, and also communicating means such as a transmitter TX SOD and a receiver RX 50E for bidirectional wired or wireless communications with the eNodeB 113 and/or the second base station 123 via, for example, one or more antennas SOF.

The eNodeB 113 includes its own processing means such as at least one data processor (DP) 1 13A, storing means such as at least one computer-readable memory (MEM) 1 13B storing at least one computer program (PROG) 1 13C, and communicating means such as a transmitter TX 1 13D and a receiver RX 1 13E for bidirectional wireless communications with other devices under its control via one or more antennas 1 13F. There is a data and/or control path, termed at Figure 6 as a control link which in the 3GPP cellular system may be implemented as an Si interface, coupling the eNodeB 113 with the MME lii, or similar CN elements, and over which the MME 111 and the eNodeB 113 may exchange control messages.

Similarly, the second base station 123 includes its own processing means such as at least one data processor (DP) I 23A, storing means such as at least one computer-readable memory (MEM) i23B storing at least one computer program (PROG) 123C, and communicating means such as a transmitter TX 123D and a receiver RX i23E for bidirectional wireless communications with other devices under its control via one or more antennas 123F. There is a data and/or control path, termed at Figure 6 as a control link which in the 3GPP cellular system may be implemented as an SI interface, coupling the second base station 123 with the second CN entity 121, or similar N elements, and over which the second CN entity 121 and the second base station 123 may exchange control messages.

The MME 111 includes processing means such as at least one data processor (DP) 11 IA, storing means such as at least one computer-readable memory (MEM) 111 B storing at least one computer program (PROG) 111 C, and communicating means such as a modem 11 IH for bidirectional communication with the eNodeB 113 over the control link.

The second CN entity 121 includes processing means such as at least one data processor (DP) 121A, storing means such as at least one computer-readable memory (MEM) 121B storing at least one computer program (PROG) 121C, and communicating means such as a modem 121H for bidirectional communication with thc sccond basc station 123 ovcr the control link. Thcrc is a data and/or control path, termed at Figure 6 as an SGs control link which in the 3GPP cellular system may be implemented as an SGs interface, coupling the MME III with the second CN entity 121, or similar CN elements, and over which the second CN entity 121 and the MME 111 may exchange control messages.

While not particularly illustrated for the TiE 50, the eNodeB 113, the second base station 123, the MME 111 and the second CN entity 121, those devices are also assumed to include as part of their wireless communicating means a modem which may be inbuilt on a radiofrequency RF front end chip within those devices 50, 113, 123, 111, 121 and which chip also carries the TX SOD/i 13D/123D/I11D/121D and the RX 50E/113E/123E/IIIE/121E.

At least one of the PROGs SOC in the TiE 50 is assumed to include program instructions that, when executed by the associated DP 50A, enable the liE to operate in accordance with the exemplary embodiments of this invention, as detailed above.

In these regards the exemplary embodiments of this invention may be implemented at least in part by computer software stored on the MEM SOB which is executable by the DP SOA of the TIE 50, or by hardware, or by a combination of tangibly stored software and hardware (and tangibly stored firmware). Electronic devices implementing these aspects of the invention need not be the entire devices as depicted at Figure 6, but exemplary embodiments may be implemented by one or more components of same such as the above described tangibly stored software, hardware, firmware and DP, or a system on a chip SOC or an application specific integrated circuit ASIC.

Various cmbodimcnts of thc computcr rcadable MEMs SOB includc any data storage technology type which is suitable to the local technical environment, including but not limited to semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, removable memory, disc memory, flash memory, DRAM, SRAM, EEPROM and the like.

Various embodiments of the DPs SOA include but are not limited to general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and multi-core processors.

Further, some of the various features of the above non-limiting embodiments may be used to advantage without the conesponding use of other dcscribcd fcaturcs.

The foregoillg description should therefore be considered as merely illustrative of the principles, teachings and exemplary embodiments of this invention, and not in limitation thereof Thc above cmbodimcnts arc to bc understood as illustrative cxamplcs of tim invention. Further embodiments of the invention are envisaged. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

Claims

Claims 1. A user equipment comprising an apparatus for use in controlling access to resources of a communication network, the communication network comprising a Paekct-Switched (PS) network comprising a plurality of eNodeBs and a Circuit-Switched (CS) network comprising a plurality of base stations (BS), each said base station being associated with a location area (LA), the apparatus being capable of receiving a CS service via the CS network and being associated with a said location area whilst being served by a said cNodeB, wherein, responsive to receiving a mobile terminated CS service notification, the user equipment is configured to change cell association to a said base station, the apparatus comprising a processing system arranged to cause the apparatus to: allocate processing resources for use in establishment of a mobile terminated CS service corresponding to the received notification; and responsive to receipt of a release message following receipt of a location area accept message, said release message being indicative of failure to provision said mobile terminated CS service, maintain said allocation of the processing resources and monitor for a service setup message from the CS network, whereby to enable establishment of said mobile terminated CS service.
2. A user equipment according to claim 1, wherein the processing system is arranged to transmit a paging response message for receipt by a core network entity in the CS network in response to receiving the release message, whereby to cause receipt of said service setup message.
3. A user equipment according to claim 1 or claim 2, wherein the processing system is arranged to configure a timer for a predetermined period of time, and maintain said allocation of the processing resources and monitor for the service setup message until the timer has reached at least the predetermined period of time.
4. A user equipment according to claim 3 when dependent on claim 2, wherein the processing system is arranged to configure said timer in response to said transmission of said paging message.
5. A user equipment according to claim 3, wherein the processing system is arranged to configure said timer in response to said allocation of the processing resources.
6. A user equipment according to any one of claim 3 to claim 5, wherein, prior to cxpiry of the prcdctermincd period of time, the processing system is arranged to process a trigger to change cell association on the basis of a predetermined rule.
7. A user equipment according to claim 6, wherein the predetermined rule comprises one or more of the following: maintain association with the base station if within coverage area thereof; establish cell association with a said base station associated with the second location area; and perform inter-RAT change of cell association if intra-RAT change of cell association not feasible.
8. A user equipment according to any one of the preceding claims, wherein the PS network comprises a Long Term Evolution (LTE) network and/or LTE Advanced, and the CS network comprises a Global System for Mobile communications (GSM) and/or a Universal Mobile Telecommunications System (UMTS).
9. A user equipment according to any one of the preceding claims, wherein the user equipment comprises a modem.
10. A user equipment according to any one of the preceding claims, wherein the user equipment is a mobile phone.
11. A method of controlling access to resources of a communication network by a user equipment, the communication network comprising a Packet-Switched (PS) network comprising a plurality of eNodeBs and a Circuit-Switched (CS) network comprising a plurality of base stations (BS), each said base station being associated with a location area (LA), the user equipment being capable of receiving a CS service via the CS network and being associated with a said location area whilst being served by a said eNodeB, wherein, responsive to receiving a mobile terminated CS service notification, the user equipment is configured to change cell association to a said base station, the method comprising: allocating processing resources for use in establishment of a mobile terminated CS service corresponding to the received notification; responsive to receipt of a release message following receipt of a location area accept message, said release message being indicative of failure to provision said mobile terminated CS service, maintaining said allocation of the processing resources; and monitoring for a service setup message from the CS network, whereby to enable establishment of said mobile terminated CS service.
12. A method according to claim 11, the method comprising transmitting a paging response message for receipt by a core network entity in the CS network in response to receiving the release message, whereby to cause receipt of said service setup message.
13. A method according to claim 11 or claim 12, the method comprising configuring a timer for a predetermined period of time, and maintaining said allocation of the processing resources and monitoring for said service setup message until the timer has reached at least the predetermined period of time.
14. A method according to claim 13 when dependent on claim 12, comprising configuring said timer in response to said transmission of said paging message.
15. A method according to claim 13, comprising configuring said timer in response to said allocation of the processing resources.
16. A method according to any one of claim 13 to claim 15, wherein, prior to expiry of the predetermined period of time, the method comprising processing a trigger to change cell association on the basis of a predetermined nile.
17. A method according to claim 16, wherein the predetermined rule comprises one or more of the following: maintain association with the base station if within covcragc area thereof; establish cell association with a said base station associated with the second location area; and perform inter-RAT change of cell association if intra-RAT change of cell association not feasible.
18. A method according to any one of claim 11 to claim 17, wherein the PS network comprises a Long Term Evolution (LTE) network and/or LTE Advanced, and the CS network comprises a Global System for Mobile communications (GSM) and/or a Universal Mobile Telecommunications System (UMTS).
19. A computer program comprising a set of instructions, which, when executed by a user equipment, causes the user equipment to perform a method of controlling access to resources of a communication network by the user equipment, the communication network comprising a Packet-Switched (PS) network comprising a plurality of eNodeBs and a Circuit-Switched (CS) network comprising a plurality of base stations (BS), each said base station being associated with a location area (LA), the user equipment being capable of receiving a CS sewice via the CS network and being associated with a said location area whilst being served by a said eNodeB, wherein, responsive to receiving a mobile terminated CS service notification, the user equipment is configured to change cell association to a said base station, the user equipment comprising a processing system arranged to cause the user equipment to: allocate processing resources!br usc in establishment of a mobile terminated CS service corresponding to the received notification; and responsive to receipt of a release message following receipt of a location area accept message, said release message being indicative of failure to provision said mobile terminated CS service, maintain said allocation of the processing resources and monitor ibr a service setup message from the CS network, whereby to enable establishment of said mobile terminated CS service
20. A user equipment comprising an apparatus for usc in controlling access to resources of a communication network, the communication network comprising a Packet-Switched (PS) network comprising a plurality of eNodeBs and a Circuit-Switched (CS) network comprising a plurality of base stations (BS), each said base station being associated with a location area (LA), the apparatus being capable of receiving a CS service via the CS network and being associated with a first location area whilst being served by a said eNodeB, wherein, responsive to receiving a mobile terminated CS service notification, the user equipment is configured to change cell association to a said base station, the base station being associated with a second location area, the apparatus comprising a processing system arranged to cause the apparatus to perform a Location Area Update (LA!)) process in the event that the first location area is different to the second location area, the Location Area Update process comprising the steps of: transmitting a LAU request message fbr receipt by a core network entity in the CS network comprising data indicative of the second location area; and responsive to receipt of a LAU process message indicative of a processing state associated with the LAU process fim the core network entity, transmitting a response message after a predetermined period of time following receipt of said LAU process message.
21. A user equipment according to claim 20, wherein the LAU process message comprises data indicative of a location update accept message, and the response message comprises data indicative of a TMSI Reallocation Complete message.
22. A user equipment according to claim 20, wherein the LAU process message comprises data indicative of an identity request, and the response message comprises data indicative of an identity corresponding to the user equipment.
23. A user equipment according to claim 20, wherein the LAU process message comprises data indicative of an authentication challenge, and the response message comprises data indicative of an authentication response.
24. A user equipment according to any one of claim 20 to claim 23, wherein the processing system is arranged to: intercept at least one Protocol Data Unit (PDU corresponding to the response message at a Mobility Management (MM) layer, the response message being generated following receipt of said LAU process message; and transmit said at least one intercepted PDU after the predetermined period of time following interception of said at least one PDIJ.
25. A user equipment according to any one of claim 20 to claim 24, wherein the PS network comprises a Long Term Evolution (LTE) network and/or LTE Advanced, and the CS network comprises a Global System for Mobile communications (GSM) and/or a Universal Mobile Telecommunications System (UMTS).
26. A user equipment according to any one of claim 20 to claim 25, wherein the user equipment comprises a modem.
27. A user equipment according to any one of claim 20 to claim 26, wherein the user equipment is a mobile phone.
28. A method of controlling access to resources of a communication network by a user equipment, the communication network comprising a Packet-Switched (PS) network comprising a plurality of eNodeBs and a Circuit-Switched (CS) network comprising a plurality of base stations (BS), each said base station being associated with a location area (LA), the apparatus being capable of receiving a CS service via the CS network and being associated with a first location area whilst being served by a said eNodeB, wherein, responsive to receiving a mobile terminated CS service notification, the user equipment is configured to change cell association to a said base station, the base station being associated with a second location area, the method comprising performing a Location Area Update (LAU) process in the event that the first location area is different to the second location area, the Location Area Update process comprising the steps of: transmitting a LAU request message for receipt by a core network entity in the CS network comprising data indicative of the second location area; and responsive to receipt of a LAU process message indicative of a processing state associated with the LAU process from the core network entity, transmitting a response message after a predetermined period of time following receipt of said LAU process message.
29. A method according to claim 28, wherein the LAU process message comprises data indicative of a location update accept message, and the response message comprises data indicative of a TMSI Reallocation Complete message.
30. A method according to claim 28, wherein the LAU process message comprises data indicative of an identity request, and the response message comprises data indicative of an identity corresponding to the user equipment.
31. A method according to claim 28, wherein the LAU process message comprises data indicative of an authentication challenge, and the response message comprises data indicative of an authentication response.
32. A method according to any one of claim 28 to claim 31, comprising: intcrcepting at icast one Protocol Data Unit (PDU) corresponding to the response message at a Mobility Management (MM) layer, the response message being generated following receipt of said LAU process message; and transmitting said at least one intercepted PDU after the predetermined period of time following interception of said at least one PDU.
33. A method according to any one of claim 28 to claim 32, wherein the PS network comprises a Long Term Evolution (LTE) network and/or LTE Advanced, and the CS network comprises a Global System for Mobile communications (GSM) and/or a Universal Mobile Tclccommunications System (UMTS).
34. A computer program comprising a set of instructions, which, when executed by a user equipment, causes the user equipment to perform a method of controlling access to resources of a communication network by the user equipment, the communication network comprising a Packet-Switched (PS) network comprising a plurality of eNodeBs and a Circuit-Switched (CS) network comprising a plurality of base stations (BS), each said base station being associated with a location area (LA), the user equipment being capable of receiving a CS service via the CS network and being associated with a first location area whilst being served by a said eNodeB, wherein, responsive to receiving a mobile terminated CS service notification, the user equipment is configured to change cell association to a said base station, the base station being associated with a second location area, the user equipment comprising a processing system arranged to cause the user equipment to perform a Location Area Update (LAy) process in the event that the first location area is different to the second location area, the Location Area Update process comprising the steps of: transmitting a LAU request message for receipt by a core network entity in the CS network comprising data indicative of the second location area; and responsive to receipt of a LAU process message indicative of a processing state associated with the LAU process from the core network entity, transmitting a response message after a predetermined period of time following receipt of said LAU process message.