CONTROL OF THE LOCATION INFORMATION

Abstract: The invention proposes a network system comprising a first network control device (RNC1), a second network control device (RNC2), and a mobile network element (MS), wherein the second network control device (RNC2) is controlled to avoid sending information to the mobile network element (MS) in case the control of the connection of the mobile network element (MS) is moved from the first network control device (RNC1) to the second network control device (RNC2). By this network system, the movement of the mobile network element between two different radio areas can be controlled such that no confusion due to receiving the information from the second network control element (e.g., location information) can occur. The invention also proposes a corresponding network control method.

Description: Control of the Location Information FIELD OF THE INVENTION The present invention relates to a ■ network system and method for controlling the movement of a mobile station between different radio areas. BACKGROUND OF THE INVENTION The invention relates to the third generation system. In particular, the invention relates to an UMTS network system, and, furthermore, to the GSM system and mainly to a system which consists of GPRS core network which is connected via Iu-PS to the GERΔN (GSM Edge Radio Access Network) , UTRAN (UMTS Terrestrial Radio Access Network) or IP-RAN. A simple UMTS network comprises a Core Network (CN) functionality, a Radio network Controller (RNC) functionality and at least one Base Station (BS) . The CN functionality can be implemented, for example, in a Serving GPRS (General Packet Radio Server) Support Node (SGSN) . In general, a GPRS Support Node (GSN) contains functionality required to support GPRS. In one PLMN (Public Land Mobile Network) , there may be more than one GSN. The GSN can be a Gateway GPRS Support Node (GGSN) or a Serving GPRS Support Node (SGSN) . The GGSN provides a gateway functionality, that is, provides an interface to other networks. On the other hand, the SGSN is the node that is serving a Mobile Station (MS) . The SGSN and GGSN functionalities may be combined in the same physical node, or they may reside in different physical nodes. SGSN and GGSN contain IP routing functionality, and they may be interconnected with IP routers. The SGSN may send location information to the Mobile Switching Center (MSC) /Visitor Location Register (VLR) . The RNC serves to provide a connection between the SGSN and the Base Stations, to which mobile stations can be connected. Usually, a network contains a plurality of RNCs. Thus, the RNC which controls and contains information, such as security parameters, bearers negotiated, etc., for a certain mobile station is a so-called Serving RNC (SRNC) . Each RNC may control a plurality of base stations. A Routing Area (RA) contains a plurality of base stations. Routing Area is used e.g. at SGSN initiated paging related to SGSN services. The mobile station updates its location to the SGSN in the routing area level. A mobile station may roam between different cells each of which being controlled by a base station. In case the base stations concerned are controlled by the same RNC, there occur no problems. However, if the mobile station roams to a cell controlled by a base station which is connected to another RNC, a SRNC relocation is necessary. In particular in case the RNCs concerned are controlled by different SGSN, there occur problems during the relocation. Namely, there might be irritation concerning which entity actually controls the mobile station. Also due to different network configurations it may sometimes be difficult to the mobile station to know by which means it needs to update its location to the entities . SUMMARY OF THE INVENTION Therefore, the object underlying the invention resides in solving the above-described problems. According to the invention, this object is solved by a network system comprising ~ ' a first network control device, a second network control device , and a mobile network element, wherein the second network control device controls the sending of the information to the mobile network element in case the control of the connection of the mobile network element is moved from the first network control device to the second network control device. Alternatively, the above object is solved by a method for controlling a network which comprises a first network control device, a second network device and a mobile network element, the method comprising the step of controlling that the second network control device sends a predetermined information to the mobile network element in case the control of the connection of the mobile network element is moved from the first network control device to the second network control device. Thus, according to the invention, the above problem can be solved by controlling the sending of certain information which may cause irritation. Namely, by such a control the sending of certain information can be completely avoided. Hence, a core network (CN) control unit such as a SGSN (Serving GPRS Support Node) cannot be confused by receiving information which are not meant for this CN control unit. That is, by the network system and the method according to the invention, the movement of the mobile network element between two different network entities and also routing areas can be controlled such that no confusion due to receiving the location update information from the mobile network element can occur. In addition, the radio resources are optimized since unnecessary information messages are avoided. That is, transmitting of the information allocated to the second network control element is suppressed. This means, for example, the information triggering a location update and the actual location update (and/or Routing area update) from the mobile station is suppressed. Hence, the traffic load on the network and on the air interface is reduced. The type of information sent by the second network control device can be controlled. Hence, a specific type of information the sending of which is to be controlled can be chosen. That is, not all information is controlled, but only a certain type which can cause irritation. The control of sending of the information may be such that it is avoided that the information is sent. That is, the information is not sent in case it can cause irritation. The location information may be the routing area identity and/or the location area identity. The information which is sent by the second network control device may be location information. The location update triggered by the sending of the location information to the mobile network element are in particular the reason why a confusion may occur in the CN entity. The information may be an IP network prefix, or may be a Router Advertisement. The first and second network control devices may be Radio Network Controllers (RNC) . The network system may further comprise a second main network control unit, which is allocated to the second network control device. The first network control device may be connected to at least one network element via which it can be connected to the mobile station. Also, the second network control device may be connected to at least one network element via which it can be connected to the mobile station. A location update may be performed by the network. That is, handling of the location update is not performed by the mobile station but by the network. That is, the network controls sending of the location information by the second network control device to the mobile station such that the mobile station does not start the location update . The entity controlling the sending of the information to the mobile station may be a core network entity (e.g., an SGSN or an Access Network Router (ANR) ) or the first network control device. Furthermore, a core network control of the connection may be maintained at a first core network control unit allocated to the first network control device after the control of the connection has been moved from the first network control device to the second network control device. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be more readily understood with reference to the accompanying drawing in which: Fig. 1 illustrates a network system comprising two radio areas, each controlled by an own Radio Network Controller (RNC) , Fig. 2 illustrates the network system shown in Fig. 1, wherein a first SGSN is anchored, Fig. 3 illustrates the network system shown in Fig. 1, wherein a location update is handled by an SGSN without that the MS sends a location update, and Fig. 4 illustrates an example in which no location update but a Mobile IP version 6 binding update is performed. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In the following, a preferred embodiment of the invention is described in more detail with reference to the accompanying drawing. In a dedicated radio connection the serving RNC (Radio Network Controller) (SRNC) controls the location information sent to the MS (Mobile Station) which in turn triggers location and/or Routing Area updating in the MS if the area has changed. The SRNC must always send location information belonging to its control area, i.e. cells which are controlled and connected to it. The problem in above cases is described in Fig. 1. Fig. 1 shows two Routing areas RA1 and RA2. In this example, RA1 comprises three base stations BS1 to BS3, and RA2 comprises three base stations BS4 to BS6. The base stations BS1 to BS3 of RA1 are controlled by a Radio Network Controller RNCl. The base stations BS4 to BS6 of RA2 are controlled by a Radio Network Controller RNC2. Furthermore, RNCl may be controlled by a Serving GPRS (General Packet Radio Service) Support Node SGSNl, whereas RNC2 may be controlled by a Serving GPRS Support Node SGSN2. In case of the so-called turbo charger concept (multipoint Iu) RNCl and RNC2 may be controlled by both SGSNl and SGSN2. In the example of Fig. 1, a mobile station MS moves from the RNCl area RA1 to the RNC2 area RA2. In the CN (Core Network) , the SGSN 1 has controlled the connection when the MS was under control of RNCl and was registered to RA1. As illustrated in Fig. 1 by the circles, RNCl has controlled before, i.e., has performed the old control before the SRNC relocation, whereas RNC2 performs the new control after the SRNC relocation. The SGSNl performs the CN control in both cases. When the MS moves to the area of the RNC2, the network performs SRNC relocation. This is indicated by the arrow from the RNCl to the RNC2. It may occur that in this case also SGSNl is changed to SGSN2. Therefore, the MS has to perform a Routing Area Update (RAU) to the SGSN2 in order to change the control of the SGSN and possibly update the MSC/VLR by performing the combined RAU. This has been triggered by the RNC2 when it has sent location information to the MS which indicates that the MS is under RA2. However, in this example the CN control point is not changed and therefore SGSNl is still controlling, even after the SRNC relocation is performed. This is illustrated in Fig. 1 by the connection between the SGSNl and the RNC2. It may be in some network configurations that the SGSNl does not control the RA2. However, it is possible to perform handovers for the MS to RNC2 and RA2 and still maintain the control in the SGSNl. In this case the RNC2 must not send any location information indicating that the MS is under RA2, because the MS is controlled by SGSNl. It may be in some network configurations that the SGSNl controls the RA2. In this case the RNC2 should not send any location information indicating that the MS is under RA2, because the MS is controlled by SGSNl. This can be used to optimise the air interface capacity. Furthermore, it is noted that the RNC2 may send the location information to the MS via RNCl also. Thus, according to the present embodiment, the CN controls the sending of the location information from the RNC, and the SGSNl indicates in the SRNC relocation request message that no location information is to be sent from the RNC2 to the mobile station MS. The CN controls the sending of the location information from the RNC. In the case described in Fig. 1 the SGSNl indicates in the SRNC relocation request message (sent to RNC2) that no location information is sent to MS. It is noted that the CN entity (i.e., the SGSNl) may indicate to the target network control device (which may be an RNC) that "no location information should be send to the MS, because it will result in a location update which is not needed" . This is because the RNC relocation procedures at the moment always involve the CN entity (ies) . Nevertheless, this indication can also be sent by the RNCl or by the SGSN2 . It is noted, that the SGSN2 only exists if a SGSN change (from SGSNl to SGSN2) is executed together with the RNC relocation. Thus, according to the invention, an error case can be avoided when the MS updates location. A further example where the error specifically occurs is the case where RNCl is controlled by a Serving GPRS (General Packet Radio Service) Support Node SGSNl, whereas RNC2 is controlled by a Serving GPRS Support Node SGSN2. In this case the SGSN change is performed, and, only after this, the location information is sent to the mobile station (MS) . However, e.g. if the SGSN is not changed in case where the SGSN anchored the error case occurs if the MS sends a location update to the CN network (in this case the location update goes to the anchor SGSNl which does not control the new location area(RA2).) This situation is illustrated in Fig. 2 in which same reference signs denote same elements as in Fig. 1. In Fig. 2, the SGSNl is anchored and the SGSN2 serves as a relay SGSN. That is, the SGSNl controls the connection to the MS although it is in the area normally controlled by the SGSN2. In this case, the SGSN2 serves basically only to forward corresponding messaging and signaling between the MS and the anchor SGSNl. According to the invention this problem is solved, as described above, by instructing the RNC2 that it should not send the location information to the MS which indicate RA2. Thus, the CN domain (i.e., the anchor SGSNl) is not confused by the MS which is actually located in RA2 although the SGSNl normally controls the RA1. One additional example is described in the following with reference to Fig. 3, in which same reference signs denote same elements as in Fig. 1. In this example, it is possible to update the location information in the CN without the MS sending any location update. In this case the network relocates the RNC and the SGSN (i.e., the connection (s) controlled by RNC2 and SGSN2) and SGSN2 updates the location database from the location information it receives from the RNC in the SRNC relocation procedure. After this the SGSN2 only indicates to the MS that its current location is the RA2. The MS updates the SIM (Subscriber Identity Module) based on this message. Also in this case, e.g., the SGSN2 controls the sending of the location information by the RNC2 to the MS in order that the MS does not start the location updating, because the location update is handled by the network. Hence, in particular in the example of Fig. 3, the radio resources are optimized since no unnecessary location information updates are transmitted, thus reducing the load on the network. ' Additionally it is possible that there may be some other types of CN entities in the CN which may need some other types of updates instead of the normal RA updating (location update) as for the GPRS core network. In this case it should be possible to control when the information is sent to the mobile station e.g. by the new RNC in case of the SRNC relocation and the type of the information sent to the mobile station. One example for such a core network (CN) is a core network which is based on the IP based mobility management, namely Mobile IP or IP version 6 mobility. The CN consists of Access Network Routers (ANR) which contain e.g. IPv6 mobility agent. This is illustrated in Fig. 4, wherein same reference characters as used in Fig. 1 represent same or similar elements . In the case illustrated in Fig. 4, it is controlled when e.g. the RNC sends the information. Furthermore, the RNC sends a Router Advertisement message with a IP subnetwork prefix indicating that the mobile station has changed the IP subnetwork and performs a Binding Update to the core network. Thus, also in this example the core network entity (i.e., the SGSN or ANR) can get confused by the messages during or immediately after an SRNC relocation is performed, similar to the case of a location update described with respect to Figs. 1 to 3. Hence, according to the present invention, sending of these messages is suppressed. It is noted that the information can be sent by another entity of the network which is responsible therefor. The above description and accompanying drawing only illustrate the present invention by way of example. Thus, the embodiment of the invention may vary within the scope of the attached claims . For example, as an alternative, the RNC can be configured to know all CN domains and the cells which are controlled by them. That is, e.g., the RNCl would know in this case that the SGSNl controls cells of the base stations BS1 to BS3 and that the SGSN2 controls cells of the base stations BS4 to BS6. In this way, the RNC would know when it can send the location information or not. The invention is also applicable to concepts such as turbo charger and the separation of the control and transport. This concepts change the one to one correspondence of the RNC and CN domain (i.e., either MSC (Mobile Switching Center) or SGSN) . That is, any CN domain may be connected to any RNC in the same PLMN (Public Land Mobile Network) . If the CN domain can be anchored or non-anchored, this operation has a different problem but the same solution may be used for this case also. Currently, the MS always starts the location updating. However, it may be possible that the location updating is executed in the network without the MS starting the procedure. If the network is capable of starting the location updating, then according to the present invention, the terminals can be prevented from starting the location updating if the MS has crossed a location area border.

Claims: Claims 1. A network system comprising a first network control device (RNCl) , a second network control device (RNC2), and a mobile network element (MS) , wherein the sending of information by the second network control device (RNC2) to the mobile network element (MS) is controlled in case the control of the connection of the mobile network element (MS) is moved from the first network control device (RNCl) to the second network control device (RNC2) . 2. The network system according to claiml, wherein the type of the information sent by the second network control device may be controlled. 3. The network system according to claim 1, wherein the information is location information. 4. The network system according to claim 1, wherein the control of sending of the information is such that it is avoided to send the information. 5. The network system according to claim 3, wherein the location information is the routing area identity and/or the location area identity. 6. The network system according to claim 1, wherein the information is IP subnetwork prefix. 7. The network system according to claim 1, wherein the information is a Router Advertisement. 8. The network system according to claim 1, wherein the first and second network control devices (RNCl, RNC2) are Radio Network Controllers. 9. The network system according to claim 1, further comprising a second core network control unit (SGSN2) which is allocated to the second network control device (RNC2) . 10. The network system according to claim 1, wherein the first network control device (RNCl) is connected to at least one fixed network element (BSl) via which it ; can be connected to the mobile station (MS) . 11. The network system according to claim 1, wherein the second network control device (RNC2) is connected to at least one fixed network element (BSl) via which it can be connected to the mobile station (MS) . 12. The network system according to claim 3, wherein the network is adapted to perform a location update. 13. The network system according to claim 1, wherein the entity controlling the sending of the information to the mobile station is a core network entity (SGSNl, SGSN2, ARN) . 14. The network system according to claim 1, wherein the entity controlling the sending of the information to the mobile station is the first network control device (RNCl) . 15. The network system according to claim 1, wherein a first core network control unit (SGSNl) allocated to the first network control device (RNCl) is adapted to maintain a core network control of the connection after the control of the connection has been moved from the first network control device (RNCl) to the second network control device (RNC2) . 16. A method for controlling a network which comprises a first network control device (RNCl), a second network device (RNC2), and a mobile network element (MS), the method comprising the step of avoiding that the second network control device (RNC2) sends a predetermined information to the mobile network element (MS) in case the control of the connection of the mobile network element (MS) is moved from the first network control device (RNCl) to the second network control device (RNC2). 17. The method according to claim 16, further comprising the step of controlling the type of the information sent by the second network control device. 18. The method according to claim 16, wherein the predetermined information is location information. 19. The method according to claim 16, wherein the control of sending of the information is such that it is avoided to send the information. 20. The method according to claim 16, wherein the location information is the routing area identity and/or the location area identity. 21. The method according to claim 16, wherein the information is IP subnetwork prefix. 22. The method according to claim 16, wherein the information is a Router Advertisement. 23. The method according to claim 16, wherein the first and second network control devices (RNCl, RNC2) are Radio Network Controllers. 24. The method according to claim 16, further comprising a second core network control unit (SGSN2) which is allocated to the second network control device (RNC2) . 25. The method according to claim 16, wherein the first network control device (RNCl) is connected to at least one fixed network element (BSl) via which it can be connected to the mobile station (MS) . 26. The method according to claim 16, wherein the second network control device (RNC2) is connected to at least one fixed network element (BSl) via which it can be connected to the mobile station (MS) . 27. The method according to claim 18, wherein a location update is performed by the network. 28. The method according to claim 16, wherein the entity controlling the sending of the information to the mobile station is a core network entity (SGSNl, SGSN2, ARN) . 29. The method according to claim 16, wherein the entity controlling the sending of the information to the mobile station is the first network control device (RNCl) . 30. The method according to claim 16, further comprising the step of maintaining a core network control of the connection at a first core network control unit (SGSNl) allocated to the first network control device (RNCl) after the control of the connection has been moved from the first network control device (RNCl) to the second network control device (RNC2) .

Inventors: RAJANIEMI JAAKKO, RAJANIEMI, JAAKKO
Applicants: NOKIA CORP, RAJANIEMI JAAKKO, NOKIA CORPORATION, RAJANIEMI, JAAKKO
Application year: 2000
Main classification: H04Q7
IPC codes: H04W36, H04W92