WO2013120506A1

WO2013120506A1 - Apparatus, method, system and computer program product for handling request

Info

Publication number: WO2013120506A1
Application number: PCT/EP2012/052381
Authority: WO
Inventors: Laszlo Janosi
Original assignee: Nokia Siemens Networks Oy
Current assignee: Nokia Solutions and Networks Oy
Priority date: 2012-02-13
Filing date: 2012-02-13
Publication date: 2013-08-22
Anticipated expiration: 2014-08-13

Description

Description Title Apparatus, method, system and computer program product for handling request

Field of the Invention

The present invention relates to requests handling. More specifically, the present invention relates to methods, apparatuses, system and computer program product for handling request.

Background of the Invention Communication networks such as Global System for Mobile Communications (GSM, often called 2G) and Universal Mobile Terrestrial System (UMTS, often called 3G) provide services to subscribers regardless of their location. In these networks, the information relating to location of a UE (user equipment) may be stored in registers such as a home location register (HLR) and a visitor location register (VLR). The HLR may store subscriber parameters permanently and the current location of a UE, whereas the VLR may store all relevant data concerning a subscriber when a UE (user equipment) used by the subscriber is within the area controlled by that visitor location register.

Evolved Packet System (EPS), the successor of GPRS (General Packet Radio System), comprises Evolved Packet Core network (EPC) and Universal Terrestrial Radio Access Network (Evolved UTRAN or E-UTRAN). It provides radio interface and packet core network functions for broadband wireless data access. The functional entities within the scope of EPC are, for example, the Mobility Management Entity (MME), Packet Data Network Gateway (PDN-GW) and Serving Gateway (S-GW).

MME is the responsible for mobility management procedures in EPS. It is responsible for locating a UE's location in the E-UTRAN; it may authenticate the subscriber and supervise the resources granted for subscribers via controlling the Gateways.

As illustrated in Fig.1 , a UE 100 is available for service under both EPS and 2G/3G. It may be camped on either E-UTRAN 102 or UTRAN/GERAN (GSM/EDGE Radio Access

Network) 101 , but not on two access networks simultaneously. In other words, if the UE is camped on E-UTRAN, it is not reachable over UTRAN or GERAN. Being camped on a radio access network means a UE is fully attached to the access network. It may listen to all the channel of the radio access network (paging, broadcast, etc).

During the initial period of EPS deployments (e.g. when EPS access is available in spotted areas), CS (Circuit Switched) Fallback (CSFB) functionality is needed in order to make services such as call, SMS (Short Message Service), location service and USSD (Unstructured Supplementary Service Data) available for UEs that are camped on E- UTRAN as these services are normally provided by CS network due to its wider coverage compared with EPS. CSFB feature enables a UE to change its radio access technology from, e.g. LTE (Long term Evolution)/EPS, to a 2G/3G technology (e.g. UTRAN/GERAN) that supports circuit-switched services. SGs is the interface between MME 121 and MSC (Mobile Switching Center)/MSS (Mobile Switching Server) 11 1/1 13.

When a UE 100 registers in EPS, it may indicate its CSFB capability to MME 121. If EPS supports CSFB, the MME 121 may perform a location update procedure via SGs interface towards a MSC/MSS 11 1 on behalf of the UE. The MSS 1 11 may download CS subscription data from a HLR 112 with normal location update procedure. After that, the UE 100 may be registered in the MSS, too. When Mobile terminated CS events (e.g. call, SMS, mobile-terminated location request) arrive at the MSS 1 11 , it may send a Paging Request to MME 121 over SGs interface to indicate the incoming CS event and MME 121 may search for the UE 100. In general, any request that activates procedures only executable under 2G/3G may trigger a Paging Request (for the purpose of paging a UE) to be send to a MME via SGs interface. These request may be, for example, MAP (Mobile Application Part) Provide Subscriber Information request (MAP PSI), MAP Provide Location Information request (MAP PLI) and Network Initiated Supplementary Service request (Nl SS).

Since the UE 100 is camped on EPS, the paging procedure may force the UE 100 to fall back to CS access network (e.g. UTRAN/GERAN) 101 with CS Fallback procedure as shown in Fig.1. When the service is completed, the UE may return to EPS.

Cells of E-UTRAN are grouped into Tracking Area (TA), just like cells in GERAN/UTRAN are grouped into Location Area (LA). A Tracking Area may be controlled one or more MME. A Location Area (LA) may be controlled by a MSS. However, Tracking Area and Location Area are not aligned. When the UE 100 falls back to 2G/3G access network, it may fall back to a LA which is not controlled by the MSS 1 11 that has initiated the paging request via SGs interface. Such situation may cause the paging procedure fail and eventually makes the original procedure/request that triggered the paging procedure fail as well. Summary of the Invention

The present invention and its embodiments seek to address one or more of the above- described drawbacks and shortcomings. According to an exemplary first aspect of the invention, there is provided a method for a first apparatus comprising receiving a first request executable to a UE when operating in a first access network, wherein said UE being attached to a second access network and operable in either of the first and the second access network; sending a second request to a first node controlling said UE in the second access network in order to locate said UE; receiving an indication indicating said UE being under control of a second apparatus in the first access network; obtaining an address of said second apparatus; and forwarding said first request to said second apparatus.

According to one embodiment of the invention, wherein obtaining the address of said second apparatus comprises sending a third request to a second node to request said address, and receiving the requested address.

According to further development of the invention, said method further comprises receiving a fourth request comprising a temporary identity of said UE and sending another identity of said UE in response to the fourth request.

According to another embodiment of the invention, wherein obtaining the address of said second apparatus comprises receiving a fifth request comprising said address from said second apparatus. According to further modification of the invention, wherein said fifth request comprises a temporary identity of said UE and said fifth request requesting another identity of the UE.

According to further modification of the invention, said method further comprises sending another identity of said UE in response to the fifth request. According to another aspect of the invention, said method further comprises receiving a response to the first request from said second apparatus and sending the response to a network element that initiated the first request. According to a third aspect of the invention, said indication indicating said UE being under control of the second apparatus in the first access network further comprises either a MAP cancel location message or a MAP send identification message.

According to a fourth aspect of the invention, there is provided a first apparatus comprising a processor, a memory unit, a receiver and a transmitter. Said receiver is configured to receive a first request executable to a UE when operating in a first access network, wherein said UE being attached to a second access network and operable in either of the first and the second access network. Via said transmitter, said processor is configured to send a second request to a first node controlling said UE in the second access network in order to locate said UE. Said receiver is configured to receive an indication indicating said UE being under control of a second apparatus in the first access network. Said processor is configured to obtain an address of said second apparatus, and to forward said first request to said second apparatus via said transmitter. According to a third embodiment of the invention, wherein, in order to obtain the address of said second apparatus, said processor is further configured to send a third request to a second node to request said address, and to receive the requested address.

According to further modification of the invention, wherein said processor is further configured to receive a fourth request comprising a temporary identity of said UE and to send another identity of said UE in response to the fourth request.

According to a fourth embodiment of the invention, wherein, in order to obtain the address of said second apparatus, said processor is further configured to receive a fifth request comprising said address from said second apparatus.

According to further development of the invention, wherein said fifth request comprises a temporary identity of said UE and said fifth request requesting another identity of the UE . According to further modification of the invention, said processor is further configured to send another identity of said UE in response to the fifth request. According to a fifth embodiment of the invention, said processor is further configured to receive a response to the first request from said second apparatus and to send the response to a network element initiated the first request.

According to a sixth embodiment of the invention, wherein said indication indicating said UE being under control of the second apparatus in the first access network comprises either a MAP cancel location message or a MAP send identification message. According to a fifth aspect of the invention, there is provided a computer program product for a first apparatus comprising. Said computer program product comprises means for receiving a first request executable to a UE when operating in a first access network, wherein said UE being attached to a second access network and operable in either of the first and the second access network; means for sending a second request to a first node controlling said UE in the second access network in order to locate said UE; means for receiving an indication indicating said UE being under control of a second apparatus in the first access network; means for obtaining an address of said second apparatus; and means for forwarding said first request to said second apparatus.

Brief Description of the Drawings

Exemplary embodiments of the invention are described below, by way of example only, with reference to the following numbered drawings.

Figure 1 is an exemplary example illustrating a network architecture under which a UE may be operating.

Figure 2 illustrates a situation where a request is rejected.

Figure 3 illustrates other situations where requests are rejected. Figure 4 shows a solution according to one aspect of the invention. Figure 5 shows another solution according to another aspect of the invention. Figure 6 shows a solution according to a further aspect of the invention.

Figure 7 depicts a schematic block diagram illustrating an apparatus according to one embodiment of the invention.

Description of the Embodiments of the Invention

Figure 2 illustrates a situation where a request is rejected due to the unavailability of a UE. A UE 100 is registered in both EPS and 2G/3G GERAN/UTRAN 101 and available for the service from either of the access networks (i.e. E-UTRAN and GERAN/UTRAN) as shown in step 203. Both the EPS and the UE 100 support CSFB. The UE 100 is camped on EPS via E-UTRAN 102 access network. A Gateway Mobile Location Center (GMLC) may request celljd, geographical information about the UE 100 by sending a message MAP PLI Request 204, which is a mobile terminated event (MT), to a first MSS 11 1. Upon receiving the request, the first MSS may initiate a paging request to a MME 121 via SGs interface. The MME 121 may receive SGsAP-PAGING-REQUEST 205 from the first MSS 11 1. If the UE 100 is in EMM-IDLE mode, the MME 121 may start a paging procedure 206 in E-UTRAN in order to locate the UE. If the UE 100 is in EMM-CONNECTED mode, the MME 121 already has a direct connection to the UE 100. Then there is no need to page the UE. The MME 121 may use the existing connection to send a notification 206 to the UE 100 about the incoming MT Event. The MME 121 may sends SGsAP-SERVICE- REQUEST 207 back to the first MSS 11 1 , indicating that the UE 100 has been located in E-UTRAN access network and has been notified about the incoming MT event. The UE 100 may thus fall back to 2G/3G and connect to a second MSS 1 13, being different from the first MSS 1 11 , controlling a LA where the UE 100 is located after the fallback as depicted in step 208.

It is a fact that the UE 100 may fall back to a LA that is not under the control of the first MSS 11 1 which initiated the paging procedure. If that happens, the UE 100 may initiate a Location Update Request 209 towards the second MSS 113 that controls the LA where the UE 100 is currently located. After a standard location update procedure 210 between a HLR 1 12 and the second MSS 1 13, the HLR 1 12 may inform the first MSS 11 1 that the UE 100 is under the control of another MSS (e.g. the second MSS 1 13) by sending a MAP Cancel Location message 21 1 to the first MSS 11 1. As the paging procedure 205 initiated by the first MSS 1 11 is not successful due to the unavailability of the UE 100, the first MSS 11 1 may send MAP PLI Reject message 212 to GMLC. The initial request 204 thus fails.

Figure 3 illustrates another situation where requests can be rejected. In addition to MAP PLI, requests such as MAP PSI and Nl SS as shown in step 304, which may be sent by a HLR 1 12 for instance, could also trigger a paging procedure. Similar to what has been described in Fig.2, due to the fact that the UE 100 may fall back to a LA that is not controlled by the first MSS 1 11 which initiated the Paging procedure, the request may fail for the same reason as explained above.

Figure 4 describes a solution according to one aspect of the invention. A request, such as MAP Provide Location Information 404, may trigger a first MSS 11 1 to page a UE 100 just as described in Fig.2. The steps 401 to 410 in Fig. 4 are identical to steps 201 to 210 in Fig.2. Assuming in step 409, the UE 100 may identify itself by an identifier associated with a subscriber, e.g. an IMSI (International Mobile Subscriber Identity), when sending the Location Update Request towards a second MSS 1 13 which controls a LA where the UE 100 is located after the fallback. The second MSS 113 may initiate a location update procedure 410 together with a HLR 112. The HLR 1 12 may inform the first MSS 1 11 that the UE 100 is now registered in another MSS (e.g. the second MSS 113) by sending a message, e.g. MAP Cancel Location 41 1. At this moment, the first MSS 111 may determine that the paging request sent over SGs interface to a MME 121 may not be answered because the UE 100 has fallen back to a LA not under its control. It may send a MAP Send Info for LCS (Location Service) message 412 towards the HLR 1 12 in order to obtain the address of the second MSS 1 13 that controls the UE 100 at the moment. Said message may comprise an identity of the UE, e.g. a MSISDN (Mobile Subscriber ISDN

Number) or an IMSI. In response to the message, the HLR 1 12 may provide an address of the second MSS 113 to the first MSS 1 11 by sending e.g. MAP Send Info for LCS

Response message 413. The address of the second MSS 113 may be an E.164 address, for instance. E.164 is an ITU-T (International Telecommunication Union- Telecommunication Standardization Sector) recommendation that defines the international public telecommunication numbering plan used in the PSTN (Public Switched Telephone Network) and some other data networks. It also defines the format of telephone numbers. After receiving the address of the second MSS 113, the first MSS 1 11 may forward the initial request (i.e. MAP Provide Location Information) 405 that triggered the paging procedure to the second MSS step 415. The second MSS 1 13 may start a location update procedure 416 towards the UE 100. It may keep the signalling connection with the UE 100 for certain period of time after the procedure ends. If the request from the first MSS 11 1 is received during this period of time, the second MSS 113 may use the existing signalling connection with the UE 100. No new paging is needed. If the request from the first MSS 11 1 arrives after the connection is released, the second MSS 1 13 may need to page the UE 100 again over A/lu interface. The second MSS 113 may obtain the requested information from the paging procedure or via the existing connection with the UE 100 and forward them to the first MSS 1 11 by e.g. sending a MAP Provide Location Information Response message 417. At step 418, the first MSS 1 11 may send the received information to the network element originated the initial request 404.

According to other embodiments of the invention, the request 404 which may trigger the paging procedure may also be MAP PSI or Nl SS as described in Fig.3. The solution described above may also be applicable to these situations. Figure 5 describes a solution according to another aspect of the invention. In Fig.5, steps 501 to 509 are identical to steps 401 to 409 in Fig.4. However, when sending the Location Update Request 509 to the second MSS 1 13, the UE 100 may optionally identify itself with another identifier associated with a subscriber, e.g. a Temporary Mobile Subscriber Identity (TMSI). In order to avoid a subscriber from being identified or tracked, a TMSI sometimes may be used instead of an IMSI. The Location Update Request may comprise the information relating to the previous LA where the UE 100 was located before the fallback. The TMSI may comprise a Network Resource Identifier (NRI) that may be used to identify a MSS (i.e. the first MSS 11 1) of which the UE was under control before the fallback. Generally speaking, every MSS may be aware of the MSSes which control its neighbouring LA. So, based on the received information relating to the LA, the second

MSS 113 may identify the identity of the first MSS 1 11 from its own database. When the second MSS 1 13 detects that the UE 100 is using a TMSI, it may send a message 510 comprising the TMSI to the first MSS 11 1 in order to inquiry the corresponding IMSI and authentication vectors. Such request may also be an indication to the first MSS 11 1 that the UE 100 has fallen back to a LA that is controlled by another MSS, e.g. the second

MSS 113. The first MSS 1 11 may provide the requested IMSI to the second MSS by sending a MAP Send Identification Response message 51 1. Assuming that there are other network elements, e.g. Signal Transfer Point, placed between the first MSS 111 and the second MSS 113, the first MSS 11 1 may not be able extract the address of the second MSS 1 13 even though the messages are exchanged between them indirectly. Once the second MSS 1 13 obtains the IMSI, it may initiate a location update procedure 512 together with a HLR 112. In step 513, the first MSS 11 1 may send a message (e.g. MAP Send Info for LCS) comprising an identity of the UE (e.g. IMSI) to the HLR 1 12, requesting the address of the second MSS 1 13 which controls the UE 100 for the time being. The HLR 1 12 may send an address (e.g. E.614 address) of the second MSS 1 13 to the first MSS 11 1 via a message, e.g. MAP Send Info for LCS 514. The first MSS 1 11 may then forward the received request 504 to the second MSS 1 13 as shown in 516. The rest of the procedures in Fig.5 (i.e. 517 to 519) are similar to the corresponding procedure (i.e. 416 to 418) in Fig.4. Similar to what has been described in Fig.4, the request 504 which may trigger the paging procedure may also be MAP PSI or Nl SS as described in Fig.3. The solution described above may also be applicable to these situations.

Figure 6 describes a solution according to a further aspect of the invention. Steps 601 to 609 in Fig.6 are identical to steps 501 to 509 in Fig.5. Similar to what has been described in Fig.5, the UE 100 identifies itself with a TMSI when sending Location Update request 609. Alternatively, the first MSS 1 11 and the second MSS 1 13 may be connected to each other directly, without any intermediate network element in between. When the second MSS 113 requests the IMSI associated with the TMSI from the first MSS 1 11 by sending a message, e.g. MAP Send Identification 610, the first MSS 11 1 may also extract the address (e.g. E.164 address) of the second MSS 113. Said message 610 may also indicate the first MSS 11 1 that the UE 100 has fallen back to a LA controlled by another MSS, e.g. the second MSS 113. The first MSS 1 11 may provide the requested IMSI to the second MSS 113 by sending a response message, e.g. MAP Send Identification

Response 61 1. Then the first MSS 11 1 may forward the original request 604 to the second MSS 113 as depicted in 614. The remaining procedures (i.e. 615 to 617) are identical to the procedures (i.e. 517 to 519) in Fig.5.

Figure 7 shows a schematic block diagram illustrating an apparatus 700 according to one embodiment of the invention. Said apparatus may comprise a processor (or a processing means) 701 , a memory unit 702, a transmitter (or a transmitting means) 703 and a receiver (or receiving means) 704. It may be noted that the receiver or transmitter may be an integral transceiver or separate functional entities. Said memory unit may comprise a database (not shown in the figure). Said apparatus 700 may be a first MSS 11 1. Said receiver may receive a request 204/304/404/504/604 relating to mobile terminated event or a request that can activate procedures only executable under 2G/3G, such as MAP PSI, MAP PLI or Nl SS. Through said transmitter 703, said processor 701 may be configured to send a paging request (e.g. 405/505/605) to a MME 121 via SGs interface. It may receive an indication 41 1/510/610 indicating that a UE 100 falls back to a LA that is controlled by another apparatus, e.g. a second MSS 1 13. Said processor 701 may request an address (e.g. E.164 address) of the second MSS 113 that is controlling the LA where the UE 100 is located. Through said receiver 704, said apparatus 700 may receive the requested address of the second MSS 1 13 as shown in 413/514 or extract the address from the received message 610 sent by the second MSS 113. With the requested address, said processor 701 may forward the received request 204/304/404/504/604 to the second MSS 113 as depicted in 415/516/616 so that the request may be handled by the second MSS 113. Through said receiver 704, said apparatus 700 may receive information relating to the forwarded request from the second MSS 113 as shown in 417/518/616 and forward the received information to a network element originated the initial request 418/519/617.

For the purpose of the present invention as described above, it should be noted that

- method steps likely to be implemented as software code portions and being run using a processor at one of the server entities are software code independent and can be specified using any known or future developed programming language;

- method steps and/or devices likely to be implemented as hardware components at one of the server entities are hardware independent and can be implemented using any known or future developed hardware technology or any hybrids of these, such as MOS, CMOS, BiCMOS, ECL, TTL, etc, using for example ASIC components or DSP components, as an example;

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

- devices can be implemented as individual devices, but this does not exclude that they are implemented in a distributed fashion throughout the system, as long as the

functionality of the device is preserved.

It is to be understood that the above description is illustrative of the invention and is not to be construed as limiting the invention. Various modifications and applications may occur to those skilled in the art without departing from the scope of the invention as defined by the appended claims.

Claims

CLAIMS:

1. A method for a first apparatus (111) comprising

receiving a first request executable to a UE (100) when operating in a first access network (101), wherein said UE (100) being attached to a second access network (102) and operable in either of the first and the second access network,

sending a second request to a first node (121) controlling said UE (100) in the second access network (102) in order to locate said UE (100),

receiving an indication indicating said UE (100) being under control of a second apparatus (113) in the first access network (101),

obtaining an address of said second apparatus (113), and

forwarding said first request to said second apparatus (113).

2. The method according to claim 1 , wherein obtaining the address of said second apparatus (1 13) comprises

sending a third request to a second node (1 12) to request said address, and receiving the requested address.

3. The method according to claim 2, further comprising

receiving a fourth request comprising a temporary identity of said UE (100) and sending another identity of said UE (100) in response to the fourth request.

4. The method according to claim 1 , wherein obtaining the address of said second apparatus (1 13) comprises

receiving a fifth request comprising said address from said second apparatus(1 13).

5. A method according to claim 4, wherein said fifth request comprises a temporary identity of said UE (100) and said fifth request requesting another identity of the UE (100).

6. The method according to claim 5, further comprising sending another identity of said UE

(100) in response to the fifth request.

7. The method according to any of the preceding claims, further comprising

receiving a response to the first request from said second apparatus (1 13) and sending the response to a network element that initiated the first request.

8. The method according to any of the preceding claims, wherein said indication comprising either a MAP cancel location message or a MAP send identification message.

9. A first apparatus (700, 1 11) comprising a processor (701), a memory unit (702), a receiver (704) and a transmitter (703), wherein,

said receiver (704) is configured to receive a first request executable to a UE (100) when operating in a first access network (101), wherein said UE (100) being attached to a second access network (102) and operable in either of the first and the second access network,

via said transmitter (703), said processor (701) is configured to send a second request to a first node (121) controlling said UE (100) in the second access network (102) in order to locate said UE (100),

said receiver (704) is configured to receive an indication indicating said UE (100) being under control of a second apparatus (1 13) in the first access network (101),

said processor (701) is configured to obtain an address of said second apparatus

(1 13), and

to forward said first request to said second apparatus (113) via said transmitter

(703).

10. The apparatus according to claim 9, wherein, in order to obtain the address of said second apparatus (1 13), said processor (701) is further configured to send a third request to a second node (1 12) to request said address, and to receive the requested address.

11. The apparatus according to claim 10, wherein

said processor (701) is further configured to receive a fourth request comprising a temporary identity of said UE (100) and to send another identity of said UE (100) in response to the fourth request.

12. The apparatus according to claim 9, wherein, in order to obtain the address of said second apparatus (1 13), said processor (701) is further configured to receive a fifth request comprising said address from said second apparatus (113).

13. The apparatus according to claim 12, wherein said fifth request comprises a temporary identity of said UE (100) and said fifth request requesting another identity of the UE (100).

14. The apparatus according to claim 13, wherein said processor (701) is further configured to send another identity of said UE (100) in response to the fifth request.

15. The apparatus according to any of the preceding claims 9-14, wherein said processor (701) is further configured to receive a response to the first request from said second apparatus (113) and send the response to a network element initiated the first request.

16. The apparatus according to any of the preceding claims 9-15, wherein said indication comprises either a MAP cancel location message or a MAP send identification message.

17. A computer program product for a first apparatus (1 11) comprising:

means for receiving a first request executable to a UE (100) when operating in a first access network (101), wherein said UE (100) being attached to a second access network (102) and operable in either of the first and the second access network,

means for sending a second request to a first node (121) controlling said UE (100) in the second access network (102) in order to locate said UE (100),

means for receiving an indication indicating said UE (100) being under control of a second apparatus (1 13) in the first access network (101),

means for obtaining an address of said second apparatus (113), and

means for forwarding said first request to said second apparatus (113).