WO2011000436A1

WO2011000436A1 - Methods, apparatuses, related computer program product and data structure for connection release indication

Info

Publication number: WO2011000436A1
Application number: PCT/EP2009/058449
Authority: WO
Inventors: Joanna Pauliina Jokinen; Tom Patrik Grahn; Jarmo Johannes Virtanen; Jari Juhani Hyytiainen
Original assignee: Nokia Siemens Networks Oy
Current assignee: Nokia Solutions and Networks Oy
Priority date: 2009-07-03
Filing date: 2009-07-03
Publication date: 2011-01-06
Anticipated expiration: 2012-01-03

Abstract

It is disclosed a method (and related apparatus) comprising transmitting an application protocol message comprising an information element indicating release of a signaling connection relating to the application protocol; and a method (and related apparatus) comprising receiving the application protocol message comprising the information element.

Description

DESCRIPTION

TITLE OF THE INVENTION

Methods, apparatuses, related computer program product and DaTa structure for connection release indication

FIELD OF THE INVENTION

[0001] Examples of the present invention relate to

connection release indication. More specifically, the examples of the present invention relate to methods,

apparatuses, a related computer program product and a data structure for connection release indication. The examples of the present invention may be applicable e.g. to long term evolution (LTE) and an Sl mobility management entity (Sl-MME) interface. Sl application protocol (SlAP) may be used on the Sl-MME interface. SlAP may be based on the 3^rd generation (3G) , but the differences in architecture and protocol stack cause a behavior in LTE different from the behavior in 3G.

BACKGROUND [0002] Fig. IA shows a 3G control plane protocol stack e.g. over an Iu interface. As shown in Fig. IA, a communication network 100 may comprise a mobile station MS (or user equipment) 101, a radio network subsystem (RNS) 102 and a serving general packet radio service (GPRS) support node (SGSN) 103. The MS 101 may be connected to the RNS 102 via a Uu interface, and the RNS 102 may be connected to the SGSN 103 via an Iu-Ps interface.

[0003] The MS 101 may comprise, from bottom to top, the following 5 layers: (1) layer 1 (Ll), (2) medium access control (MAC) layer, (3) radio link control (RLC) layer, (4) radio resource control (RRC) layer and (5) a layer for GPRS mobility management/session management/short message service (GMM/SM/SMS) . The RNS 102 may be connected to the MS 101 on layers (1) to (4), while the MS 101 may be connected directly to the SGSN 103 on layer (5) . Further, the RNS 102 may be capable of relaying (or mapping) layers (1) to (4) : Ll to (a) Ll, MAC to (b) layer 2 (L2), RLC to (c) signaling bearer, and RRC to (dl) signaling connection control part (SCCP) and (d2) radio access network application part (RANAP) . Finally, the RNS 102 may be connected to the SGSN 103 on layers (a) to (c) , (dl) and (d2) .

[0004] Further, Fig. IB shows an LTE stack corresponding to the 3G stack shown in Fig. IA. As shown in Fig. IB, the communication network 100 may comprise a user equipment (UE) 101, an evolved nodeB (eNodeB or eNB) 102 and a mobility management entity (MME) 103. The UE 101 may be connected to the eNB 102 via an LTE-Uu interface, and the eNB 102 may be connected to the MME 103 via an Sl-MME interface.

[0005] The UE 101 may comprise, from bottom to top, the following 5 layers: (1) Ll, (2) MAC layer, (3) RLC layer, (4) packet data convergence protocol (PDCP) layer, (5) radio resource control (RRC) layer and (6) non-access stratum (NAS) layer. The eNB 102 may be connected to the UE 101 on layers (1) to (5) , while the UE 101 may be connected directly to the MME 103 on layer (6) . Further, the eNB 102 may be capable of relaying (or mapping) layers (1) to (5) : Ll to (a) Ll, MAC to (b) L2, RLC to (c) internet protocol (IP), PDCP to (d) stream control transmission protocol (SCTP), and RRC to (e) SlAP. Finally, the eNB 102 may be connected to the MME 103 on layers (a) to (e) .

[0006] As shown in Figs. IA and IB, in case of 3G (Fig. IA), there is the SCCP layer below RANAP layer and also in case of UE related messaging, an individual SCCP connection per each UE. In case of LTE (Fig. IB), SlAP operates directly over

SCTP, whereas UE related messages may be delivered e.g. over a few SCTP associations between UEs (or endpoints) . Thus, one difference between 3G and LTE resides in that on LTE the SlAP signaling, a connection is purely logical only without any direct reference to lower layer identifiers, whereas an Iu signaling connection relies on lower layer identification as well. Another difference resides in that on 3G, the Iu signaling connection identifier consists of a single

identifier allocated by the initiating party (e.g. radio network controller (RNC) or SGSN 103), but on LTE, the SlAP signaling connection may consist of an ID pair, both parties allocating its own part of the ID.

[0007] Further, Fig. 1C shows a UE context release

procedure. A logical SlAP signaling connection between eNB 102 and MME 103 may be released with an explicit UE context release command message from the MME 103 to the eNB 102, which the eNB 102 acknowledges by sending a UE context release complete message.

[0008] In consideration of the above, according to the examples of the present invention, methods, apparatuses, a related computer program product and a data structure for connection release indication are provided.

[0009] In this connection, the examples of the present invention enable one or more of the following:

- Utilizing a more efficient signaling, e.g. SlAP signaling connection. This is because SlAP does not impact on lower layers to release and establish signaling connections;

- Dispensing with a need for a separate request message and a corresponding acknowledgement in return;

- Clarifying an uncertainty of some use cases where it is not explicitly clear when the SlAP signaling connection is released or exists, such as path switching procedure (both successful and unsuccessful cases) and initial context setup failure procedures;

- Clarifying another uncertainty, e.g. in case of initial context setup failure, in which the SlAP signaling connection is to be released after the failure message has been received in MME. This is because in some use cases, the radio connection still exists and failure occurred e.g. due to bearer related problems, and thus the MME may still need to send e.g. a further NAS message to UE (e.g. attach reject or detach request) ;

- Avoiding an extra message pair to release the connection explicitly (e.g. UE context release command/ complete), e.g. utilizing a release indication bit e.g. on top of a downlink (DL) NAS transport message to indicate that the SlAP signaling connection is not going to be used afterwards.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The examples of the present invention are described herein below with reference to the accompanying drawings, in which:

[0011] Fig. IA shows the above-described 3G control plane protocol stack e.g. over the Iu interface; [0012] Fig. IB shows the above-described LTE control plane protocol stack e.g. over the Sl-MME interface;

[0013] Fig. 1C shows the above-described UE context release procedure;

[0014] Fig. 2 shows methods for connection release

indication according to first to fourth examples of the present invention; [0015] Fig. 3 shows apparatuses for connection release indication according to the first to fourth examples of the present invention;

[0016] Fig. 4A shows a data structure for connection release indication according to the first example of the present invention; [0017] Fig. 4B shows a data structure for connection release indication according to the second example of the present invention; [0018] Fig. 4C shows a data structure for connection release indication according to the third example of the present invention; and

[0019] Fig. 4D shows a data structure for connection release indication according to the fourth example of the present invention .

DETAILED DESCRIPTION OF THE EXAMPLES OF THE PRESENT INVENTION [0020] The examples of the present invention are described herein below by way of example with reference to the

accompanying drawings.

[0021] It is to be noted that for this description, the terms "SlAP message, initial context setup failure message (first example) , handover failure message (second example) , path switch request failure message (third example) and/or downlink NAS transport message (fourth example); indication bit; and SlAP connection" are examples for "application protocol message; information element; and signaling

connection", respectively, without restricting the latter- named terms to the special technical or implementation details imposed to the first-named terms. [0022] Fig. 2 shows methods for connection release

indication according to the first to fourth examples of the present invention. Signaling between elements is indicated in horizontal direction, while time aspects between signaling may be reflected in the vertical arrangement of the signaling sequence as well as in the sequence numbers. It is to be noted that the time aspects indicated in Fig. 2 do not necessarily restrict any one of the method steps shown to the step sequence outlined. This applies in particular to method steps that are functionally disjunctive with each other.

Within Fig. 2, for ease of description, means or portions which may provide main functionalities are depicted with solid functional blocks or arrows and/or a normal font, while means or portions which may provide optional functions are depicted with dashed functional blocks or arrows and/or an italic font.

[0023] As shown in Fig. 2, a communication system 200 may comprise a network 203. In turn, the network 203 may further comprise a first entity 201 (e.g. eNB or MME) and a second entity 202 (e.g. MME or eNB) different from the first entity 201. [0024] Further, as shown in Fig. 2, in step Sl-I, e.g. the first entity 201 may perform transmitting an application protocol message (e.g. SlAP message) comprising an

information element (e.g. indication bit) indicating release of a signaling connection relating to the application protocol.

[0025] Then, in step S2-1, e.g. the second entity 202 may perform receiving, at the second entity 202 different from the first entity 201 performing the transmitting, the application protocol message.

[0026] Furthermore, in an optional step S2-2, e.g. the second entity 202 may perform releasing the signaling connection pertaining to a terminal (e.g. UE, not shown) based on the information element. Still further, the

application protocol message may be constituted by an Sl application protocol message for which a release indication bit is applicable, as the information element, to release, as the signaling connection, a logical Sl application protocol connection.

[0027] As the first example of the method pertaining to the first and second entities 201 and 202, the application protocol message may be constituted by an initial context setup failure message.

[0028] As the second example of the method pertaining to the first and second entities 201 and 202, the application protocol message may be constituted by a handover failure message .

[0029] As the third example of the method pertaining to the first and second entities 201 and 202, the application protocol message may be constituted by a path switch request failure message.

[0030] Finally, as the fourth example of the method

pertaining to the first and second entities 201 and 202, the application protocol message may be constituted by a downlink non-access stratum transport message.

[0031] As a development pertaining to the first to fourth examples, the information element may be constituted by an indication bit providing an Sl-interface application protocol connection release indication.

[0032] Fig. 3 shows apparatuses (e.g. eNB and/or MME each assuming the role of the first entity 201 and/or the second entity 202) for connection release indication according to the first to fourth examples of the present invention. Within Fig. 3, for ease of description, means or portions which may provide main functionalities are depicted with solid

functional blocks or arrows and/or a normal font, while means or portions which may provide optional functions are depicted with dashed functional blocks or arrows and/or an italic font. [0033] The first entity 201 (e.g. eNB or MME) may comprise a CPU (or circuitry) 2011, a memory 2012, a transmitter (or means for transmitting) 2013 and an optional receiver (or means for receiving) 2014.

[0034] The second entity 202 (e.g. MME or eNB) may comprise a CPU (or circuitry) 2021, a memory 2022, an optional transmitter (or means for transmitting) 2023, a receiver (or means for receiving) 2024 and an optional releaser (or means for releasing) 2025.

[0035] As indicated by the dashed extensions of the

functional blocks of the CPU 2011 or 2021, the means for releasing 2025 (and means for transmitting 2013,

2023/receiving 2014, 2024 of the first/second entity 201, 202) may be functionalities running on the CPU 2011 or 2021 of the served entity 201 and/or serving entity 202, or may alternatively be separate functional entities or means.

[0036] The CPUs 20x1 (wherein x = 1 and/or 2) may

respectively be configured, for example by software residing in the memory 20x2, to process various data inputs and to control the functions of the memories 20x2, the means for transmitting 202x3 and the means for receiving 20x4 (and the means for releasing 2025 of the second entity 202) . The memories 20x2 may serve e.g. for storing code means for carrying out e.g. the methods according to the example of the present invention, when run e.g. on the CPUs 20x1. It is to be noted that the means for transmitting 20x3 and the means for receiving 20x4 may alternatively be provided as

respective integral transceivers. It is further to be noted that the transmitters/receivers may be implemented i) as physical transmitters/receivers for transceiving e.g. via the air interface (e.g. between a UE (not shown) and the first entity 201), ii) as routing entities e.g. for

transmitting/receiving data packets e.g. in a PS (packet switching) network (e.g. between the first entity 201 and the second entity 202 when disposed as separate network

entities) , iii) as functionalities for writing/reading information into/from a given memory area (e.g. in case of shared/common CPUs or memories e.g. of the first entity 201 and the second entity 202 when disposed as an integral network entity) , or iv) as any suitable combination of i) to iii) . [0037] Further, as shown in Fig. 3, e.g. the means for transmitting 2013 of the first entity 201 may perform transmitting an application protocol message (e.g. SlAP message) comprising an information element (e.g. indication bit) indicating release of a signaling connection relating to the application protocol.

[0038] Then, e.g. the means for receiving 2024 of the second entity 202 may perform receiving, at the second entity different from the first entity 201 comprising the means for transmitting 2013, the application protocol message.

[0039] Furthermore, optionally, e.g. the means for releasing 2025 of the second entity 202 may perform releasing, the signaling connection pertaining to a terminal (UE, not shown) based on the information element. Still further, the

[0040] As the first example pertaining to the first and second entities 201 and 202, the application protocol message may be constituted by an initial context setup failure message.

[0041] As the second example pertaining to the first and second entities 201 and 202, the application protocol message may be constituted by a handover failure message.

[0042] As the third example pertaining to the first and second entities 201 and 202, the application protocol message may be constituted by a path switch request failure message.

[0043] Finally, as the fourth example pertaining to the first and second entities 201 and 202, the application protocol message may be constituted by a downlink non-access stratum transport message.

[0044] As for the first to fourth examples, the first entity 201 and/or the second entity 202 may be constituted by a mobility management entity, an evolved nodeB or an evolved universal terrestrial radio access network nodeB.

[0045] As a development pertaining to the first to fourth examples, the information element may be constituted by an indication bit providing an Sl-interface application protocol connection release indication.

[0046] Furthermore, at least one of the above-described means for transmitting 2013, 2023, means for receiving 2014, 2024 and means for releasing 2025 as well as the first entity 201 and the second entity 202, or the respective

functionalities carried out, may be implemented as a chipset, module or subassembly. [0047] Finally, the example of present invention also relates to a system which may comprise the first entity 201 and the second entity 202 according to the above-described first to fourth examples of the present invention. [0048] Figs. 4A to 4D show data structures 300 for

connection release indication according to the first to fourth examples of the present invention.

[0049] As shown in Figs. 4A to 4D, the data structure 300 may comprise an information element 301 indicating release of a signaling connection relating to an application protocol. [0050] Further, according to the first example of the present invention shown in Fig. 4A, the data structure 300 may be constituted by an initial context setup failure message. In that case, the data structure 300 may further comprise the following information elements (IEs) : message type 302, MME-UE SlAP ID 303, eNB-UE SlAP ID 304, cause 305 and criticality diagnostics 306.

[0051] Further, according to the second example of the present invention shown in Fig. 4B, the data structure 300 may be constituted by a handover failure message. In that case, the data structure 300 may further comprise the following IEs: message type 302, MME-UE SlAP ID 303, cause 304 and criticality diagnostics 305.

[0052] Further, according to the third example of the present invention shown in Fig. 4C, the data structure 300 may be constituted by a path switch request failure message. In that case, the data structure 300 may further comprise the following IEs: message type 302, MME-UE SlAP ID 303, eNB-UE SlAP ID 304, cause 305 and criticality diagnostics 306.

[0053] Finally, according to the fourth example of the present invention shown in Fig. 4D, the data structure 300 may be constituted by a downlink non-access stratum transport message. In that case, the data structure 300 may further comprise the following IEs: message type 302, MME-UE SlAP ID 303, eNB-UE SlAP ID 304, NAS protocol data unit (PDU) 305 and handover restriction list 306.

[0054] Without being restricted to the details following in this section, the examples of the present invention may be summarized as follows: A release indication bit may be added e.g. into SlAP messages to indicate that the logical SlAP signaling connection has been released. Thus, the recipient may clear all resources related to the UE. The release bit may be allowed to be set by the MME, as the MME is the entity that controls the SlAP signaling connection release. However, e.g. in initial context setup failure and handover failure cases, the eNB may indicate to the MME right away that there is no working connection left for the UE and that the MME cannot use the signaling connection anymore.

A release indication bit may be incorporated into some SlAP messages. Herein below, some examples of those SlAP messages are shown.

INITIAL CONTEXT SETUP FAILURE

This message is sent by the eNB to indicate that the setup of the UE context was unsuccessful.

Direction: eNB → MME

HANDOVER FAILURE

This message is sent by the target eNB to inform the MME that the preparation of resources has failed.

Direction: eNB → MME

PATH SWITCH REQUEST FAILURE

This message is sent by the MME to inform the eNB that a failure has occurred in the evolved packet core (EPC) during the Path switch request procedure.

Direction: MME → eNB

DOWNLINK NAS TRANSPORT

This message is sent by the MME and is used for carrying NAS information over the Sl interface.

Direction: MME —> eNB

[0055] [Further examples] [0056] For the purpose of the present invention as described herein above, it should be noted that

- a circuitry may refer to at least one of, or hybrids of the following: (a) to pure hardware circuit implementations (such as implementations purely in analog and/or digital circuitry) , and

(b) to combinations of circuits and software (and/or firmware) , such as (as applicable) :

(i) a combination of processor (s) , or

(ii) portions of processor (s) /software (including digital signal processor (s) ), software and memory (or memories) that work together to cause an apparatus as defined hereinabove to perform various functions, and

(c) to circuits, such as (micro) processor (s) or a portion of (a) (micro) processor (s) that require software and/or firmware for operation even if the software or firmware is not physically present;

- a processor may be any processing unit, such as CPU, arithmetic and logic unit (ALU) , microprocessor unit (MPU) , digital signal processor (DSP) etc., be it a single core processor, dual core processor or multi-core processor;

- a program may be embodied by or on any computer program (product), computer readable medium, processor (s) , memory

(or memories) , circuitry, circuits, random access memory (RAM), read-only memory (ROM) and/or data structure (s) , be it e.g. as compiled/non-compiled program (source) code,

executable object, (meta) file or the like;

- an access technology may be any technology by means of which a user equipment can access an access network (or base station, respectively) . Any present or future technology, such as WiMAX (Worldwide Interoperability for Microwave Access) or WLAN (Wireless Local area Network) , BlueTooth, Infrared, and the like may be used; although the above technologies are mostly wireless access technologies, e.g. in different radio spectra, access technology in the sense of the present invention may also imply wirebound technologies, e.g. IP based access technologies like cable networks or fixed line.

- a network may be any device, unit or means by which a station entity or other user equipment may connect to and/or utilize services offered by the access network; such services include, among others, data and/or (audio-) visual

communication, data download etc.;

- generally, the present invention may be applicable in those network/user equipment environments relying on a data packet based transmission scheme according to which data are transmitted in data packets and which are, for example, based on the internet protocol (IP) . The present invention is, however, not limited thereto, and any other present or future IP or mobile IP (MIP) version, or, more generally, a protocol following similar principles as (M)IPv4/6, is also

applicable;

- a user equipment may be any device, unit or means by which a system user may experience services from an access network;

- method steps likely to be implemented as software code portions and being run using a processor at a network element or terminal (as examples of devices, apparatuses and/or modules thereof, or as examples of entities including apparatuses, circuitries and/or modules therefore) , are software code independent and can be specified using any known or future developed programming language as long as the functionality defined by the method steps is preserved;

- generally, any method step is suitable to be implemented as software or by hardware without changing the idea of the invention in terms of the functionality implemented;

- method steps and/or devices, units or means likely to be implemented as hardware components at the above-defined apparatuses, or any module (s) /circuitry (ies) thereof, are hardware independent and can be implemented using any known or future developed hardware technology or any hybrids of these, such as MOS (Metal Oxide Semiconductor) , CMOS

(Complementary MOS) , BiMOS (Bipolar MOS) , BiCMOS (Bipolar CMOS), ECL (Emitter Coupled Logic), TTL (Transistor- Transistor Logic), etc., using for example ASIC (Application Specific IC (Integrated Circuit) ) components, FPGA (Field- programmable Gate Arrays) components, CPLD (Complex

Programmable Logic Device) components or DSP (Digital Signal Processor) components; in addition, any method steps and/or devices, units or means likely to be implemented as software components may alternatively be based on any security architecture capable e.g. of authentication, authorization, keying and/or traffic protection;

- devices, units, circuitries or means (e.g. the above- defined apparatuses, or any one of their respective means) can be implemented as individual devices, units or means, but this does not exclude that they are implemented in a

distributed fashion throughout the system, as long as the functionality of the device, unit, circuitry or means is preserved;

- an apparatus may be represented by a semiconductor chip, a chipset, a (hardware) module comprising such chip or chipset, or a circuitry; this, however, does not exclude the

possibility that a functionality of an apparatus, module or circuitry, instead of being hardware implemented, be

implemented as software in a (software) module such as a computer program or a computer program product comprising executable software code portions for execution/being run on a processor;

- a device may be regarded as an apparatus or as an assembly of more than one apparatus, whether functionally in

cooperation with each other or functionally independently of each other but in a same device housing, for example. [0057] According to an example of the present invention, in a first aspect, this object is for example achieved by a method comprising:

transmitting an application protocol message

comprising an information element indicating release of a signaling connection relating to the application protocol.

[0058] According to an example of the present invention, in a second aspect, this object is for example achieved by a method comprising:

receiving an application protocol message comprising an information element indicating release of a signaling connection relating to the application protocol. [0059] According to further refinements of the example of the present invention as defined under the above second aspect,

- the method further comprises releasing the signaling connection pertaining to a terminal based on the information element .

[0060] According to further refinements of the example of the present invention as defined under the above first and second aspects,

- the application protocol message is constituted by an Sl application protocol message for which a release indication bit is applicable, as the information element, to release, as the signaling connection, a logical Sl application protocol connection;

- the application protocol message is constituted by an initial context setup failure message, a handover failure message, a path switch request failure message or a downlink non-access stratum transport message;

- the information element is constituted by an indication bit providing an Sl-interface application protocol connection release indication.

[0061] According to an example of the present invention, in a third aspect, this object is for example achieved by an apparatus comprising:

means for transmitting an application protocol message comprising an information element indicating release of a signaling connection relating to the application protocol.

[0062] According to an example of the present invention, in a fourth aspect, this object is for example achieved by an apparatus comprising:

means for receiving an application protocol message comprising an information element indicating release of a signaling connection relating to the application protocol. [0063] According to further refinements of the example of the present invention as defined under the above fourth aspect,

- the apparatus further comprises means for releasing communication resources pertaining to a terminal based on the information element.

[0064] According to further refinements of the example of the present invention as defined under the above third and fourth aspects,

- the apparatus is constituted by one of a mobility

management entity, an evolved nodeB and an evolved universal terrestrial radio access network nodeB;

- the information element is constituted by an indication bit providing an Sl-interface application protocol connection release indication;

- at least one of means for transmitting, means for

receiving, means for releasing and the apparatus is

implemented as a chipset, module or subassembly. [0065] According to an example of the present invention, in a fifth aspect, this object is for example achieved by an apparatus comprising:

a transmitter configured to transmit an application protocol message comprising an information element indicating release of a signaling connection relating to the application protocol . [0066] According to an example of the present invention, in a sixth aspect, this object is for example achieved by an apparatus comprising:

a receiver configured to receive an application protocol message comprising an information element indicating release of a signaling connection relating to the application protocol .

[0067] According to further refinements of the example of the present invention as defined under the above sixth aspect,

- the apparatus further comprises a releaser configured to release communication resources pertaining to a terminal based on the information element.

[0068] According to further refinements of the example of the present invention as defined under the above fifth and sixth aspects,

- the apparatus is constituted by one of a mobility

- at least one of a transmitter, receiver, releaser and the apparatus is implemented as a chipset, module or subassembly.

[0069] According to an example of the present invention, in a seventh aspect, this object is for example achieved by a system comprising:

an apparatus according to the above third or fifth aspects; and

an apparatus according to the above fourth or sixth aspects.

[0070] According to an example of the present invention, in an eighth aspect, this object is for example achieved by a computer program product comprising code means for performing a method according to the above first and second aspects when run on a processing means or module.

[0071] According to an example of the present invention, in a ninth aspect, this object is for example achieved by a computer program comprising code means configured to perform:

transmitting an application protocol message

comprising an information element indicating release of a signaling connection relating to the application protocol. [0072] According to an example of the present invention, in a tenth aspect, this object is for example achieved by a computer program comprising code means configured to perform:

receiving an application protocol message comprising an information element indicating release of a signaling connection relating to the application protocol.

[0073] According to an example of the present invention, in an eleventh aspect, this object is for example achieved by a data structure comprising:

an information element indicating release of a signaling connection relating to an application protocol.

[0074] According to further refinements of the example of the present invention as defined under the above eleventh aspect,

- the data structure is constituted by an initial context setup failure message, a handover failure message, a path switch request failure message, or a downlink non-access stratum transport message.

[0075] Although the present invention has been described herein before with reference to particular embodiments thereof, the present invention is not limited thereto and various modification can be made thereto.

Claims

CLAIMS :

1. A method, comprising:

transmitting an application protocol message comprising an information element indicating release of a signaling connection relating to the application protocol.

2. A method, comprising:

3. The method according to claim 2, further comprising releasing the signaling connection pertaining to a terminal based on the information element.

4. The method according to any one of claims 1 to 3, wherein the application protocol message is constituted by an Sl application protocol message for which a release indication bit is applicable, as the information element, to release, as the signaling connection, a logical Sl application protocol connection .

5. The method according to any one of claims 1 to 4 , wherein the application protocol message is constituted by an initial context setup failure message, a handover failure message, a path switch request failure message or a downlink non-access stratum transport message.

6. The method according to any one of claims 1 to 5, wherein the information element is constituted by an indication bit providing an Sl-interface application protocol connection release indication.

7. An apparatus, comprising:

8. An apparatus, comprising:

means for receiving an application protocol message comprising an information element indicating release of a signaling connection relating to the application protocol.

9. The apparatus according to claim 8, further comprising means for releasing communication resources pertaining to a terminal based on the information element.

10. The apparatus according to any one of claims 7 to 9, wherein the application protocol message is constituted by an Sl application protocol message for which a release

indication bit is applicable, as the information element, to release, as the signaling connection, a logical Sl

application protocol connection.

11. The apparatus according to any one of claims 7 to 10, wherein the application protocol message is constituted by an initial context setup failure message, a handover failure message, a path switch request failure message or a downlink non-access stratum transport message.

12. The apparatus according to claim 11, wherein the

apparatus is constituted by one of a mobility management entity, an evolved nodeB and an evolved universal terrestrial radio access network nodeB.

13. The apparatus according to any one of claims 7 to 12, wherein the information element is constituted by an

indication bit providing an Sl-interface application protocol connection release indication.

14. The apparatus according to any one of claims 7 to 13, wherein at least one of means for transmitting, means for receiving, means for releasing and the apparatus is

implemented as a chipset, module or subassembly.

15. A computer program product comprising code means for performing a method according to any one of claims 1 to 6 when run on a processing means or module.

16. A data structure, comprising:

an information element indicating release of a signaling connection relating to an application protocol .

17. The data structure according to claim 16, wherein the data structure is constituted by

an initial context setup failure message,

a handover failure message,

a path switch request failure message, or

a downlink non-access stratum transport message.