CN1206542A

CN1206542A - Load reduction of visitor location register

Info

Publication number: CN1206542A
Application number: CN 96199375
Authority: CN
Inventors: 劳里·拉蒂南
Original assignee: Nokia Telecommunications Oy
Current assignee: Nokia Oyj
Priority date: 1995-12-29
Filing date: 1996-12-20
Publication date: 1999-01-27

Abstract

A problem arises when the data of the visitor location register (VLR) are lost for some reason. In this case, only the visitor location register (VLRn) in whose area the mobile station (MS) is located is known. The mobile station (MS) must then be paged in all location areas (LAn) of the visitor location register (VLR). Such paging of mobile stations causes a significant overload. The overload is reduced, according to the invention, by dividing the physical area covered by a physical visitor location area (VLR) into areas of a plurality of logical visitor location registers (LVLRn). In connection with location updatings, not only the physical visitor location register (VLR) is stored but also information on the logical visitor location register (LVLRn); in a problematic situation where the switching centre (MSC) is not aware of the location area of the mobile station (MS), the mobile station (MS) is paged, at least at first, only in the area of the logical visitor location register (LVLRn).

Description

The load reduction of Visited Location Registor

The present invention relates to mobile communication system, relate in particular to the load reduction of Visited Location Registor in the mobile communication system.

Fig. 1 shows mobile station MS and roams in mobile radio communication or network subsystem NSS.In this embodiment, NSS comprises 6 base station BTS 1 to BTS6, and they can be controlled by one or more base station controller BSC.Each base station provides service for a sub-district.When the incoming call of MS was transferred by network N SS, NSS must know the zone that needs this MS of paging.The zone of this MS of paging is called as positioning area LA.

The size of positioning area LA is a kind of compromise.If positioning area is very big, must be in several base stations BTS zone paging MS.This means also in the base station area that travelling carriage do not occur paging they.This has wasted the capacity of wireless channel.If positioning area is less, then must often carries out the position and upgrade.Fig. 1 shows 3 positioning area LA1-LA3 by way of example, and they have covered 1,2 and 3 base station respectively.Base station BTS continue broadcasting they own with and the information of environment, for example base station identifier BSI and positioning area identifier LAI.Based on LAI, the MS that registers in BTS knows that it is at residing LA of each moment.If when a BTS moves to another BTS, MS finds that LAI has changed, and then sends a position updating request or message to network N SS.This MS Visited Location Registor VLR in zone of living at that time upgrades the LA of this MS.VLR generally stores, for example user's IMSI (IMSI International Mobile Subscriber Identity) number, Mobile Subscriber International ISDN Number, user service data and LAI.

The VLR information in MS zone of living in is sent to the attaching position register of this MS.HLR stores permanent user data, and these data and this user are at the location independent of given time: for example user's MSISDN and IMSI, user service data, and the data routing addressing is positioned at the VLR of its positioning area to this MS.

Fig. 2 has illustrated the foundation of MS incoming call in GSM type mobile communication system.If in its zone of attaching position register, then the parts of Fig. 2 are not corresponding with Fig. 1 for the MS of Fig. 1; But HLR and VLR are associated with different mobile services switching centre MSC.In step 1, call arrives Gateway Mobile Switching Center GMSC.In step 2, GMSC defines this user's attaching position register based on called subscriber's telephone number MSISDN, and sends the routing addressing request of data to this attaching position register.In this user's HLR, location update operations upgrades the VLR information in this user zone of living in.Based on this information, HLR sends a request of Providing Roaming Number to VLR in step 3.This MS user's IMSI also sends to VLR in this request.In step 4, VLR stores its received data, and distributes a mobile station roaming number MSRN.In step 5, VLR sends MSRN that it distributes to HLR, and HLR sends it to the GMSC of request routing addressing data in step 6.The definition mode of roaming number makes calling always be directed to the MSC that its VLR has distributed this roaming number.Based on this MSRN, GMSC can will call out routing addressing to the indicated MSC of this MSRN by send an initial address message in step 7.

In this embodiment, MSC finds that based on MSRN this time calling is with its zone of incoming call.In step 8, MSC is to its VLR request called subscriber's call setup data.Under normal circumstances, VLR returns the data of request to set up calling in step 9.This is by

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10 and 11 indications.

When the data of VLR are lost for some reason, then can go wrong.This can occur in, for example when VLR may be reinitialized during software upgrading or plant maintenance.In this case, only know the VLR in (based on the HLR of MS) MS zone of living in.Must be in all positioning area LA of following travelling carriage be arranged paging MS: the storage of these travelling carriages is in this VLR.If this VLR provides service for a large number of users, such travelling carriage paging mainly can cause a large amount of overloads aspect three: 1) between MSC and base station system BSS; 2) aspect the signaling process of BSS; And 3) on wireless channel.BSS comprises a base station controller BSC and a plurality of base station BTS of being controlled by this BSC.Because overload, some MS incoming call will be failed.

Therefore, target of the present invention provides a kind of device of a kind of method and this method of realization, and above-mentioned overload problem is resolved.Target of the present invention realizes that by certain methods and system the feature of these method and systems is independently disclosing in claims.Preferred embodiment is open in related right requires.

The physical region that the present invention is based on VLR is divided into a plurality of logic regions.When travelling carriage carried out the position renewal, the position updating request that is sent to HLR by VLR also comprised the information that this travelling carriage is positioned at its regional logic VLR.This information is transparent to HLR, and promptly HLR stores these data but it does not made any reaction.

Under the calling situation, resembling in the past, signaling carries out.Do not know at VLR under the error situation of MS positioning area that physics VLR receives the logic VLR address of this MS from HLR by normal signaling.This information is included in the message that Provides Roaming Number.Therefore, physics VLR is limited in the logic VLR area with paging.Under opposite extreme situations, logic VLR area even can be a positioning area.

An advantage of method and system of the present invention is, compares with prior art systems, and is much smaller at error situation lower network load.Another advantage of processing of the present invention is, and is less relatively to the change that existing system carried out, and for example makes amendment in MSC software.These are changed in all fields all and the existing system compatibility.Like this, network can (simultaneously and more neatly) adopt according to the improved switching center of the present invention with not according to the improved switching center of the present invention.

Below in conjunction with accompanying drawing, by preferred embodiment the present invention is described in more detail, in the accompanying drawings

Fig. 1 shows the mobile phone mesh portions important to the present invention;

Fig. 2 shows the mobile telephone network signaling process step important to the present invention;

Fig. 3 shows the positioning area of mobile telephone network, and this positioning area is divided into a plurality of logical access location registers.

Referring to Fig. 3, according to the present invention, become a plurality of logical access location register LVLRn by area dividing with physical access location register VLR, limited the overload of mobile telephone network.For simplicity's sake, the physics VLR area only is divided into two logical access location register LVLR1 and LVLR2 in Fig. 3.In actual applications, in physics VLR area the right quantity n of LVLR can, for example be 5 to 10.The system of Fig. 3 need do following improvement on the prior art scheme of Fig. 1 and 2:

1. define and name the LVLR of right quantity.In name, for example after VLR number, use 1 or 2 bit digital just enough.

2.MSC the message at the renewal of MS position that sends to HLR also comprises the LVLR information in this MS zone of living in.This information is transparent to HLR, and promptly HLR handles its common number as physics VLR, and it is only than long 1 or 2 bit digital under the situation that does not have LVLR identifier n.

3. under the situation of MS incoming call, handle not what difference, because certain reason is lost, promptly VLR does not know the positioning area of MS up to the VLR data.In this case, MSC (and VLR) receives the LVLR identifier of MS from HLR by normal signaling (in the message that Provides Roaming Number).Based on this information, this MSC can be limited in the paging to MS in the LVLR zone.

According to prior art, for example following information stores is in HLR:

The IMSI number of travelling carriage is	The GT address of the VLR in zone of living in is
IMSI	NCC NDC VLRn

Wherein:

The GT=worldwide name

The NCC=national code

NDC=national goal ground sign indicating number

VLRn=Visited Location Registor number

According to the present invention, following information respective stored is at HLR:

Wherein

The number (1 or 2 bit digital) of LVLR in the nn=physics VLRn.

According to the present invention, a VLR is appointed as a plurality of LVLR can for example improves realization as software at MSC.Software improves as follows:

1.MSC must the affiliated positioning area LAn of record logical access location register LVLRn.

2. when upgrading in the position of MS, MSC also must send the HLR of the LVLRn information in MS zone of living in to this MS.

3. under the error situation of physics VLR loss of data, when paging MS, MSC must at least at first be limited in paging the LVLRn zone that this MS position was updated last time.

Visited Location Registor VLR is divided into (perhaps a VLR being designated as) a plurality of logical access location register LVLRn and has reduced the congested peak value that error situation is taken place down.If the quantity n of the LVLR in the physics VLR area is for example 5, this MS of 1/5th pagings that only must its zone then, thus correspondingly reduced the caused load of paging.Yet exist a side effect: the number of times that the position is upgraded also increases with same coefficient.But, reduce benefit that congested peak value the brings position of being eager to excel and upgrade the defective that caused additional traffic brings.

To those skilled in the art, obvious above-mentioned example all is intended to illustrate the present invention in every respect, rather than the present invention is made qualification.More than at gsm system the present invention has been described by example, but the present invention also can be applied to the mobile communication system of other type.Therefore, the present invention and embodiment are not limited to above-mentioned example, can make improvements in the scope of appended claim book.

Claims

1. method of in digital mobile telephone network (NSS), upgrading travelling carriage (MS) position, wherein the information of the physical access location register (VLR) in attaching position register (HLR) storing mobile station (MS) zone of living in is characterized in that,

The zone that-physical access location register (VLR) is covered is divided into a plurality of logical access location registers (LVLRn) zone; And

-except physical access location register (VLR), attaching position register (HLR) is gone back the information of the logical access location register (LVLRn) in storing mobile station (MS) zone of living in.

2. when the mobile services switching centre when digital mobile telephone network (MSC) was lost positioning area (LA) information of travelling carriage (MS), the method for mobile paging station (MS) is characterized in that in this mobile services switching centre (MSC) zone,

The zone that the physical access location register (VLR) of-switching center (MSC) is covered is divided into a plurality of logical access location registers (LVLRn) zone; And

-mobile paging station (MS) in logical access location register (LVLRn) zone of indication travelling carriage last time at least at first only.

3. the mobile services switching centre of a digital mobile telephone network (MSC), described switching center comprises a physical access location register (VLR), and physical access location register (VLR) information in different mobile stations (MS) zone of living in sent to the attaching position register (HLR) of mobile telephone network, it is characterized in that

-switching center (MSC) also sends to attaching position register (HLR) with logical access location register (LVLRn) information in different mobile stations (MS) zone of living in.

4. the location update message in the digital mobile telephone network (NSS), described message comprises Visited Location Registor (VLR) information in travelling carriage (MS) zone of living in, it is characterized in that this location update message also comprises logical access location register (LVLRn) information in travelling carriage (MS) zone of living in.