MXPA00005272A - Method for routing area (ra) update - Google Patents

Abstract

The present invention relates to a method for routing area (RA) update request messages which in accordance with a time period broadcasted from the network are periodically sent from an MS (Mobile Station) to an SGSN (Serving GPRS Support Node) through a BSS (Base Station System), which SGSN supports GPRS (General Packet Radio Service), and which as a result of a routing area update procedure will return an appropriate accept message, and for the purpose of taking into account the differentiation in nature of normal routing area update procedure and periodic updates, it is according to the present invention suggested that for the purpose of simplifying said routing area update procedure, there is broadcasted a new indicator from the network together with the time period for the periodic routing updates, said indicator being adapted to determine whether the periodic routing update procedure is performed ciphered instead of unciphered.

Description

METHOD TO UPDATE ROUTINE ROUTING (RA) FIELD OF THE INVENTION The present invention relates to a method for routing area update (RA) request messages that according to a transmission time from an associated network are periodically sent from an MS (Mobile Station) to an SGSN (GPRS Server Support Node) through a BSS (Base Station System), whose SGSN supports GPRS (Radio Service in General Packages), and which as a result of a procedure of Routing area update will return an appropriate acceptance message.

BACKGROUND OF THE INVENTION The GPRS (General Packet Radio Service), which is currently being specified by ETSI, as a service for phase 2+ of GSM, provides connections connected in packets through the PLMN. (Public Network, Land Mobile). Packet switching is performed between the nodes of the network and at the radio interface. The most important part of the transmission is between an MS (Mobile Station) and the SGSN (Serving GPRS Support Node, GPRS Support Node Server). The unpredictable change of the position of an MS has caused the desire for very frequent update messages from the MS to the network. These frequent messages provoke a face on the air interface internally within the SGSN. The protocol stack for GPRS between the MS and the SGSN is outlined in Figure 1.

The problem area In order for the mobile telephone system to know the position of a mobile station and if the mobile station actually has radio contact with the system, periodic messages are specified from the mobile stations. The time between the periodic messages is transmitted from the network to the mobile stations. With a scenario of 100,000 subscribed subscribers and a 15 minute update interval, a considerable number of routing update procedures must be performed every minute. This will consume a significant part of the total processor capacity for the SGSN.

Prior art The current procedure will be described in the following: The messages Routing rea Update Request (Request for Routing Area Update) must be sent unencrypted, since in the case of the routing area update between the SGSNs, the new SGSN must be able to process the request. The procedure for updating the intra SGSN routing area is illustrated in Figure 2. The example assumes that the MSC / VLR does not change during the routing update. Each step is explained in the illustrated list in Figure 2. 1) The MS sends a message Routing Area Update Request (Routing Area Update Request) (TLLI, new Cl, old RAI, new RAI) to the SGSN. The Cl is added in the BSS to reduce the load on the radio interface. 2) Security functions can be executed. 3) The SGSN validates the presence of the MS in the new RA. If, by regional, national or international restrictions, the MS is not allowed to join in the RA or the subscription check fails, then the SGSN rejects the routing update with an appropriate cause. If all the checks are successful, then the SGSN updates the MM context for the MS. It is possible to assign a new TLLI. Return to the MS a Routing rea Update Accept message (Accept Routing Area Update) (TLLI, Cause). 4. If I change the TLLI, the MS recognizes the new TLLI with Routing rea Update Complete (TLLI) (Complete the Routing Area Update). If the procedure for updating the routing area fails a maximum number of times, or if the Routing Area Update Accept Cause parameter indicates a rejection, the MS must enter the IDLE state (inactive) .

Disadvantage of the prior art The assumption of the work does not take into account the differentiation in the nature of the procedure of updating the normal routing area (always in an unknown area) and the periodic updates (always in a known area).

OBJECTIVES OF THE INVENTION An object of the present invention is to provide a method by which the drawbacks of the prior art are eliminated. Another object of the invention is to provide a method for routing area update request messages wherein the processor load consumption is reduced. Still another object of the present invention is to take into account the differentiation in the nature of the normal procedure for updating the routing area and the periodic updates.

BRIEF SUMMARY OF THE INVENTION The aforementioned objects are achieved by a method as set forth in the preamble, which according to the present invention is characterized in that, for the purpose of simplifying the updating procedure of the routing area, a new indicator from the network together with the time for periodic routing updates, the indicator being adapted to determine if the periodic routing update procedure is done encrypted instead of not encrypted. In other words, it is proposed that a new indicator be transmitted from the network along with time for periodic routing updates. This indicator determines whether the periodic routing update procedure is performed encrypted instead of unencrypted as is normally done. This results in a new variant of the routing area update. It is also possible to add a second information element from the SGSN, to indicate the number of periodic, consecutive route area updates to be performed before an update procedure of the routing area including security functions is carried out. Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, as well as from the attached patent clauses.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a sketch illustrating the protocol stack for GPRS between the MS and the SGSN. Figure 2 is a list illustrating an update procedure of the intra SGSN routing area of the prior art. Figure 3 is a list illustrating a periodic procedure for updating the routing area of the SGSN according to the present invention.

Description of the modalities From the above description, it should be noted that Figure 1 is a sketch illustrating the protocol stack for GPRS between the MS and the SGSN, while Figure 2 is a list illustrating the updating procedure of the intra-SGSN routing area according to the prior art. With reference to Figure 3 a detailed description will now be given of how a method embodiment of the method according to the present invention can be performed. The periodic procedure for updating the routing area of the SGSN is illustrated in Figure 3. Each step is explained in the list illustrated therein. 1) The MS sends a message Routing Area Update Request (TLLI, Cl, RAI, periodic indicator of the RA) to the SGSN. The Cl is added in the BSS to reduce the load on the radio interface. The MS initiates the periodic routing area update procedure only in the case of no change in the routing area. The MS may decide to perform, for example, every fifth periodic RA update as a normal RA update to possibly change the authorization data. 2) The fact that the SGSN recognizes the message after decryption, and that the periodic RA indicator is present, validates the presence of the MS in the RA. The SGSN updates the MM context for the MS. A new TLLI can be assigned. The MS returns a Routing Area Update Accept message (TLLI, Cause) 3) If I change the TLLI, the MS recognizes it in the new TLLI with Routing Area Update Complete (TLLI) (Complete the Update of the Routing Area). If the procedure for updating the routing area fails a maximum number of times allowed, or if the Routing rea Update Accept Cause parameter indicates a rejection, the MS must enter the IDLE state (inactive).

SUMMARY OF THE INVENTION The proposed solution can be characterized by providing a simpler periodic routing area update procedure. By allowing the procedure to be encrypted, it is verified that the correct subscriber is addressed.

Merits of the invention The invention makes it possible to have a more efficient handling of the messages of periodic updating, as they are presented in a known routing area and therefore they can be handled like other information known by the MS and the SGSN. Then the information can be sent, for example, in encrypted form. In addition, the method according to the present invention can be defined by sending an indicator to the mobile stations, in order thereby to handle the periodic routing area update procedures in encrypted or unencrypted form according to the decision of the operator.

In addition, the method according to the present invention makes it possible to allow mobile stations, at certain defined intervals, to handle periodic routing area updates as updates to the ordinary routing area to perform security functions.

Still further, the present invention defines the principle of allowing the updating procedure of the periodic routing area to be sent in encrypted or unencrypted form.

Claims (5)

1. A method for routing area update (RA) request messages that according to a time transmitted from the network are periodically sent from an MS (Mobile Station) to a service node, and that as a result of a procedure of routing area update will return an appropriate acceptance message, it is characterized because for the purpose of simplifying the routing area update procedure, a new indicator is transmitted from the network along with time for periodic routing updates, the indicator being adapted to determine whether the encrypted periodic routing update procedure is performed instead of not encrypted.

2. The method as mentioned in claim 1, characterized in that a second information element is added from the service node, whose information element can indicate the number of consecutive periodic routing updates that are to be made before it is performed. perform a routing area update procedure that includes security features.

3. The method as recited in claim 1 or 2, characterized in that the MS involved initiates the periodic routing area update procedure only in the case of no change of the routing area t

4. The method as mentioned in Claim 3 is characterized in that the MS involved is adapted to decide to perform only some periodic RA updates as a normal RA update, for example every fifth periodic RA update, to possibly change the authorization data.

5. The method as mentioned in any of the preceding claims, characterized in that, when the service node recognizes the message after decryption and the presence of the indicator, then the service node will validate the presence of the MS involved in the area of routing, whereby the MM context of the MS is updated and a new TLLI can possibly be assigned (Temporary Logic Link Identity, Identity of the Temporal Logical Link).