DESC:FIELD OF INVENTION

[0001] The present invention relates to wireless communications, and more particularly to a method for triggering a Mobility Management (MM) specific procedure in a wireless communication network after detecting an intersystem change, routing area update (RAU) is failed and successful generic location updating procedure is not performed. The present application is based on, and claims priority from an Indian Application Number 5617/CHE/2014 filed on 7th November, 2014, the disclosure of which is hereby incorporated by reference herein.
BACKGROUND OF INVENTION
[0002] In today wireless telecom scenarios, as the technology such as Global System for Mobile Communications (GSM)/Universal Mobile Telecommunications System (UMTS)/Long-Term Evolution (LTE) getting progressed towards efficient band utilization, there is also continuous need of maintaining a Quality of Services (QoS) with existing mobile feature like Short Message Service (SMS), Multimedia Messaging Service (MMS), Browsing, and Emergency services and so on. One of the important features is Mobile Originated (MO)/Mobile Terminated (MT) call. As per current implementation, there are cases, where user equipment (UE) can miss a MT call paging due to state mismatch between the UE and a wireless communication network.
[0003] In an example, when initially UE was registered for both Circuit Switched (CS) and Evolved Packet System (EPS) services with a Mobility Management Entity (MME) and if the UE reselects to Universal Terrestrial Radio Access Network (UTRAN)/ GSM EDGE Radio Access Network (GERAN) cell (referred as an intersystem change), but in a same location area identity (LAI) as registered LAI. Thus, the MM is not performing location area update (LAU). Then GPRS Mobility Management (GMM) initiated Routing Area Update (RAU) and received RAU Reject due to a network failure at Serving GPRS Support Node (SGSN) and the GMM attempts to update its state and start timer T3302 (after attempt counter is 5). Now, the MM is assuming that it is in a registered area of a Mobile Switching Center (MSC) and hence not performing the LAU and even the GMM has failed to perform RAU successfully. Hence, the context of UE is not transferred from S1 mode to Iu/AGb mode, and for the MME the UE is still in its registered area. It leads to a registration state mismatch between the UE and the wireless communication network. Further, if there is any MT paging for the UE, the MSC forwards the paging to the MME through a SGs interface. Now, the MME pages the UE in the LTE area, but actually the UE is in the UTRAN/GERAN area. Hence, the UE will miss the MT paging.
[0004] In another example, after the intersystem change from the S1 mode to a Iu mode or a A/Gb mode, even though the UE is in MM registered area, the RAU was tried and if GMM still fails due to RAU reject from the wireless communication network (due to congestion, network failure at SGSN and so on), to successfully register with network, so the UE misses the MT Call paging.
[0005] The above information is presented as background information only to help the reader to understand the present invention. Applicants have made no determination and make no assertion as to whether any of the above might be applicable as Prior Art with regard to the present application.
OBJECT OF INVENTION
[0006] The principal object of the embodiments herein is to provide a method for triggering a Mobility Management (MM) specific procedure after detecting an intersystem change, routing area update (RAU) is failed and a successful generic location updating procedure is not performed since the intersystem change.
SUMMARY

[0007] Accordingly the embodiment herein provides a method for triggering a Mobility Management (MM) specific procedure. The method includes detecting an intersystem change from a S1 mode to either an A/Gb mode or an Iu mode. Further, the method includes detecting that a routing area update (RAU) is failed. Further, the method includes detecting that a successful generic location updating procedure is not performed since the detected intersystem change. Furthermore, the method includes triggering the MM specific procedure based on detecting that the RAU is failed and the successful generic location updating procedure is not performed. The MM specific procedure corresponds to a Location Area Update (LAU).
[0008] Accordingly the embodiment herein provides a mobile station (MS) operated in a wireless communication network. The MS is configured to detect an intersystem change from a S1 mode to either an A/Gb mode or an Iu mode. Further, the MS is configured to detect that a routing area update (RAU) is failed. Further, the MS is configured to detect that a successful generic location updating procedure is not performed since the detected intersystem change. Furthermore, the MS is configured to trigger a MM specific procedure based on detecting that the RAU is failed and the successful generic location updating procedure is not performed. The MM specific procedure corresponds to a LAU.
[0009] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF FIGURES
[0010] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0011] FIG. 1 illustrates generally, among other things, a high level overview of wireless communication network in which a mobile station (MS) triggers a Mobility Management (MM) specific procedure, according to embodiments as disclosed herein;
[0012] FIG. 2 illustrates various units in the MS, according to embodiments as disclosed herein;
[0013] FIG. 3 is a flow diagram illustrating a method for triggering the MM specific procedure, according to embodiments as disclosed herein;
[0014] FIG. 4a is a sequence diagram explaining steps involved in triggering a Location Area Update (LAU) when a routing area updating (RAU) attempt counter is greater than or equal to 5, according to embodiments as disclosed herein; and
[0015] FIG. 4b is a sequence diagram explaining steps involved in triggering a LAU when a normal and periodic RAU procedure is not accepted by a wireless communication network, according to embodiments as disclosed herein.

DETAILED DESCRIPTION OF INVENTION
[0016] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term “or” as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0017] Throughout the description, the terms Mobile Station (MS) and user equipment (UE) are used interchangeably.
[0018] The embodiments herein achieve a method for triggering a Mobility Management (MM) specific procedure. The method includes detecting an intersystem change from a S1 mode (LTE) to either an A/Gb mode (GERAN) or an Iu mode (UTRAN). Further, the method includes detecting that a routing area update (RAU) is failed. Further, the method includes detecting that a successful generic location updating procedure is not performed since the detected intersystem change. Furthermore, the method includes triggering the MM specific procedure based on detecting that the RAU is failed and the successful generic location updating procedure is not performed. In an embodiment, the MM specific procedure corresponds to a Location Area Update (LAU).
[0019] In an embodiment, a RAU attempt counter is greater than or equal to 5 indicates that RAU is failed for 5 times (as specified in 3GPP TS 24.008 and 4.7.5.1.5- Abnormal cases in MS mentioned below).
4.7.5.1.5 - Abnormal cases in the MS
If the routing area updating attempt counter is greater than or equal to 5:
[0020] A GPRS MS operating in MS operation mode A or B in network operation mode II which is configured to use CS fallback and Short Message Service (SMS) over SGs, or SMS over SGs only, and which did not perform a successful generic location updating procedure since the last intersystem change from the S1 mode to the A/Gb or the Iu mode shall proceed with appropriate MM specific procedures.
[0021] In an embodiment, the RAU is failed when a normal and periodic RAU procedure is not accepted by a wireless communication network (as specified in 3GPP TS 24.008 and 4.7.5.1.4- Normal and periodic routing area updating procedure not accepted by the network as mentioned below). In an example, the wireless communication network can send the reject cause to indicate that network has not accepted the normal and periodic RAU procedure sent by the UE.
[0022] 4.7.5.1.4 - Normal and periodic routing area updating procedure not accepted by the network:
[0023] Reject- 9 (MS identity cannot be derived by the network): a GPRS MS operating in MS operation mode A or B in network operation mode II which is configured to use CS fallback and SMS over SGs, or SMS over SGs only, and which did not perform a successful generic location updating procedure since the last intersystem change from the S1 mode to the A/Gb or the Iu mode shall proceed with appropriate MM specific procedures. Additionally, a GPRS MS operating in MS operation mode A or B in network operation mode II shall initiate a GPRS attach procedure
[0024] Reject- 10 (Implicitly detached): a GPRS MS operating in MS operation mode A or B in network operation mode II which is configured to use CS fallback and SMS over SGs, or SMS over SGs only, and which did not perform a successful generic location updating procedure since the last intersystem change from S1 mode to A/Gb or Iu mode shall proceed with appropriate MM specific procedures.
[0025] Unlike conventional systems, the proposed method avoids the missing of paging for a MT call or a MT CS services. The proposed method avoids wasting of time by a mobile station (MS) in attempting to update state after the RAU failure to bring back the CS services. Further, the proposed method avoids wastage of paging resources in the LTE area, when the UE is camped in a Legacy Radio Access Technology (RAT). The method also avoids registration state mismatch between the MS and the wireless communication network.
[0026] Referring now to the drawings, and more particularly to FIGS. 1 through 4b, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
[0027] FIG. 1 illustrates generally, among other things, a high level overview of wireless communication network 100 in which a mobile station (MS) triggers a Mobility Management (MM) specific procedure, according to embodiments as disclosed herein. The wireless communication network 100 includes a MS 102, a SGSN 104, a MME 106, and a MSC/Visitor Location Register (VLR) 108. The MS 102 is in communication with the SGSN 104, the MME 106, and the MSC/VLR 108. The MME 106 is in communication with the MSC/VLR 108 over a SGs interface. The SGs interface is a reference point between the MME 106 and MSC/VLR 108. The SGs interface is used for the MM and paging procedures between an EPS domain and a CS domain. The MS 102 can be, for example but not limited to, a mobile communication device, a mobile wireless device, a tablet, a handset, a smart phone, a laptop, or any other communication device. The MS 102 can include one or more antennas configured to communicate with a base station (BS), an evolved Node B (eNB), or other type of nodes in the wireless communication network 100.
[0028] The SGSN 104 is a node that is serving the MS 102. The SGSN 104 supports a GPRS for the A/Gb mode (i.e. the Gb interface) and/or Iu-mode (i.e. the Iu interface).
[0029] Initially, the MS 102 is registered for both CS and EPS services with the MME 104. The MS 102 detects an intersystem change from the S1 mode (LTE) to either the A/Gb mode (GERAN) or the Iu mode (UMTS) since MS 102 has reselected to one of a UMTS cell or a GERAN cell. Further, the MS 102 is configured to detect that the RAU is failed. The MS 102 send the RAU request to the SGSN 104. In response, the SGSN 104 sends RAU failure to the MS 102.
[0030] If the MS 102 detects that the normal and periodic RAU procedure is not accepted by the wireless communication network 100, then the MS 102 that the triggers the MM specific procedure which corresponds to LAU request.
[0031] After the MS 102 sends the LAU request to the MSC/VLR 108. In response, the MSC/VLR 108 sends the LAU accept response to the MS 102. Then after mechanism defined in 3GPP specification follows.
[0032] The FIG. 1 shows a limited overview of the wireless communication network 100 but, it is to be understood that other embodiments are not limited thereto. Further, the wireless communication network 100 can include any number other hardware or software components communicating with each other. For example, the component can be, but not limited to, a process running in the controller or processor, an object, an executable process, a thread of execution, a program, or a computer. By way of illustration, both an application running on a device and the device itself can be a component.
[0033] FIG. 2 illustrates various units in the MS 102, according to embodiments as disclosed herein. The MS 102 includes a detection unit 202, a RAU managing unit 204, a counter 206a, a timer 206b, a LAU triggering unit 208, and a call handling unit 210. The detection unit 202 is configured to detect the intersystem change from the S1 mode to either the A/Gb mode or the Iu mode. Further, the detection unit 202 is configured to detect that the RAU is failed. Furthermore, the detection unit 202 is configured to detect that the successful generic location updating procedure is not performed since the detected intersystem change. The RAU managing unit 204 is configured to detect that the normal and periodic RAU procedure is not accepted by the wireless communication network 100. Then, the LAU triggering unit 208 is configured to trigger the MM specific procedure, when the normal and periodic RAU procedure is not accepted by the wireless communication network 100.
[0034] In an embodiment, after receiving the RAU failure from the wireless communication network 100, the counter 206a is configured to perform the RAU attempts for greater than or equal to 5 times. The LAU triggering unit 208 is configured to trigger the MM specific procedure, when the RAU attempt counter is greater than or equal to 5. In an embodiment, the triggering involves sending the LAU request to the wireless communication network 100.
[0035] In response, the LAU triggering unit 208 is configured to receive the LAU accept from the wireless communication network 100. Then the wireless communication network 100 sends the paging for the MT call and the call handling unit 210 is configured to send the paging response to the wireless communication network 100. Then, the call handling unit 210 is configured to handle the MT call.
[0036] Although FIG. 2 shows exemplary units of the MS 102, in other implementations, the MS 102 may include fewer components, different components, or additional components than depicted in the FIG. 2. Additionally or alternatively, one or more components of the MS 102 may perform functions described as being performed by one or more other components of the MS 102.
[0037] FIG. 3 is a flow diagram illustrating a method 300 for triggering the MM specific procedure to the wireless communication network, according to embodiments as disclosed herein. At step 302, the method 300 includes detecting the intersystem change from the S1 mode to either the A/Gb mode or the Iu mode. In an embodiment, the method 300 allows the detection unit 202 to detect the intersystem change from the S1 mode to either the A/Gb mode or the Iu mode. The intersystem change refers to the cell reselection by the MS 102 from the LTE to either UMTS or GERAN. At step 304, the method 300 includes detecting that the RAU is failed. In an embodiment, the method 300 allows the detection unit 202 to detect that the RAU is failed.
[0038] At step 306, the method 300 includes detecting that a successful generic location updating procedure is not performed since the detected intersystem change. In an embodiment, the method 300 allows the detection unit 202 to detect that the successful generic location updating procedure is not performed since the detected intersystem change.
[0039] At step 308, the method 300 includes triggering the MM specific procedure based on detecting that the RAU is failed and detecting that the successful generic location updating procedure is not performed. In an embodiment, the method 300 allows the LAU triggering unit 208 to trigger the MM specific procedure based on detecting that the RAU is failed and detecting that the successful generic location updating procedure is not performed. In an embodiment, the MM specific procedure corresponds to LAU request.
[0040] At step 310, the method 300 includes sending the LAU request to the MSC/VLR 108 in the wireless communication network 100. In an embodiment, the method 300 allows the LAU triggering unit 208 to send the LAU request to the MSC/VLR 108 in the wireless communication network 100.
[0041] At step 312, the method 300 includes determining whether the LAU accept received from the MSC/VLR 108. In an embodiment, the method 300 allows the LAU triggering unit 208 to determine whether the LAU accept received from the MSC/VLR 108. If the LAU accept is received from the MSC/VLR 108 then, at step 314, the method 300 includes receiving the paging via the A/Gb mode or the Iu mode. In an embodiment, the method 300 allows the call handling unit 210 to receive the paging via the A/Gb mode or the Iu mode. If the LAU accept is not received from the MSC/VLR 108 then, at step 316, the method 300 includes performing actions as per 3GPP standard.
[0042] At step 318, the method 300 includes sending a paging response to the MSC/VLR 108. In an embodiment, the method 300 allows the call handling unit 210 to send the paging response to the MSC/VLR 108. The proposed method 300 avoids the registration state mismatch between the MS 102 and the wireless communication network 100.
[0043] The various actions, acts, blocks, steps, and the like in the method 300 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions, acts, blocks, steps, and the like may be omitted, added, modified, skipped, and the like without departing from the scope of the invention.
[0044] FIG. 4a is a sequence diagram explaining steps involved in triggering the LAU when the RAU attempt counter is greater than or equal to 5, according to embodiments as disclosed herein. Initially, the MS 102 registers (402a) for the CS/EPS services with the MME 106 in S1 mode and the MS 102 reselects (404a) to either the A/Gb mode or the Iu mode. When the MS 102 reselected to either the A/Gb mode or the Iu mode, the MS 102 sends (406a) the RAU request to the SGSN 104 and the MS 102 receives the RAU failure from the SGSN 104.
[0045] The MS 102 determines (408a) that an RAU attempt counter is greater than or equal to 5 indicating that the RAU is failed 5 times. Then, the MS 102 sends (410a) the LAU request to the MSC/VLR 108. In response to the LAU request received from the MS 102, the MSC/VLR 108 sends (412a) the LAU accept response to the MS 102. The Gateway Mobile Switching Centre (G-MSC) 408 sends (414a) a paging for MT call to the MSC/VLR 108. Then, the MSC/VLR 108 sends (416a) the paging via the Iu mode or the A/Gb mode on the GERAN or UTRAN area to a NodeB/Base Station Controller (BSC) 402. After receiving the paging via the Iu mode or the A/Gb mode, the NodeB/BSC 402 sends (418a) the paging to the MS 102. In response, the MS 102 sends (420a) the paging response to the MSC/VLR 108. This avoids the registration state mismatch between the MS 102 and the MSC/VLR 108. Then the MS 102 continues (422a) the MT call with the MSC/VLR 108.
[0046] FIG. 4b is a sequence diagram explaining steps involved in triggering the LAU when the normal and periodic RAU procedure is not accepted by the wireless communication network 100, according to embodiments as disclosed herein. Initially, the MS 102 registers (402b) for the CS/EPS services with the MME 106 in S1 mode, and the MS 102 reselects (404b) to either the A/Gb mode or the Iu mode. When the MS 102 reselects to either the A/Gb mode or the Iu mode, the MS 102 sends (406b) the RAU request to the SGSN 104 and the MS 102 receives the RAU failure from the SGSN 104.
[0047] The MS 102 determines (408b) the normal and periodic RAU procedure is not accepted by the wireless communication network 100 due to problems such as congestion, network failure at the SGSN, and so on). The wireless communication network 100 indicates the non-acceptance of the normal and periodic RAU procedure by sending a reject cause. Then the MS 102 sends (410b) the LAU request to the MSC/VLR 108. In response, the MSC/VLR 108 sends (412b) the LAU accept response to the MS 102.
[0048] The G-MSC 408 sends (414b) a paging for MT call to the MSC/VLR 108. Then the MSC/VLR 108 sends (416b) the paging via the Iu mode or the A/Gb mode on the GERAN or UTRAN area to the NodeB/BSC 402. Then the NodeB/BSC 402 sends (418b) the paging to the MS 102. In response, the MS 102 sends (420b) the paging response to the MSC/VLR 108 and the MS 102 continues (422b) the MT call with the MSC/VLR 108.
[0049] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the elements. The elements shown in FIGS. 1, 2, 4a, and 4b include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.
[0050] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
,CLAIMS:STATEMENT OF CLAIMS
We claim:

1. A method implemented in a mobile station (MS), the method comprising:
detecting an intersystem change from a S1 mode to one of a A/Gb mode and a Iu mode;
detecting that a routing area update (RAU) is failed;
detecting that a successful generic location updating procedure is not performed since said detected intersystem change; and
triggering a Mobility Management (MM) specific procedure based on detecting that said RAU is failed and said successful generic location updating procedure is not performed, wherein said MM specific procedure corresponds to a Location Area Update (LAU).
2. The method of claim 1, wherein triggering said MM specific procedure comprises determining that an attempt counter is greater than or equal to 5 indicating that said RAU is failed 5 times.
3. The method of claim 1, wherein said RAU is failed when a normal and periodic RAU procedure is not accepted by a wireless communication network.
4. A mobile station (MS) operated in a wireless communication network, the mobile station is configured to:
detect an intersystem change from a S1 mode to one of a A/Gb mode and a Iu mode;
detect that a routing area update (RAU) is failed;
detect that a successful generic location updating procedure is not performed since said detected intersystem change; and
trigger a Mobility Management (MM) specific procedure based on detecting that said RAU is failed and said successful generic location updating procedure is not performed, wherein said MM specific procedure corresponds to a Location Area Update (LAU).
5. The MS of claim 4, wherein said MS is configured to trigger said MM specific procedure in response to determining that an attempt counter is greater than or equal to 5 indicating that said RAU is failed 5 times.
6. The MS of claim 4, wherein said RAU is failed when a normal and periodic RAU procedure is not accepted by a wireless communication network.

Dated: 12th Day of October, 2015 Signature
Arun Kishore Narasani.
Patent Agent.