WO1998031163A2

WO1998031163A2 - Method and apparatus for implementing alias mobile id numbers in a mobile telephone system

Info

Publication number: WO1998031163A2
Application number: PCT/US1998/000493
Authority: WO
Inventors: James A. Lamb
Original assignee: Tandem Computers, Incorporated
Priority date: 1997-01-11
Filing date: 1998-01-09
Publication date: 1998-07-16
Also published as: WO1998031163A3

Abstract

An improved home location register (HLR) that implements alias mobile ID numbers (MIN) in a mobile telephone system. According to the invention, the improved HLR includes an alias MIN module that comprises an alias MIN table and an alias MIN application program. The alias MIN table associates multiple phone numbers of a cellular phone to the cellular phone's preprogrammed MIN. When the HLR receives dialed digits from an MSC in a location request, the application program uses the dialed digits as key to locate the associated MIN of the receiving party's cellular phone. The retrieved MIN is then included in the routing message and forwarded to the appropriate MSC that currently serves the receiving party's cellular phone. In this way, the subscriber can be reached by dialing any of the pre-associated phone numbers. Therefore, significant convenience is provided to cellular subscribers and wireless service providers.

Description

METHOD AND APPARATUS FOR IMPLEMENTING ALIAS MOBILE ID NUMBERS

IN A MOBILE TELEPHONE SYSTEM

BACKGROUND OF THE INVENTION

The invention generally relates to a wireless communication network, and more particularly, relates to an improved home location register (HLR) that implements alias mobile ID numbers in a wireless communication network.

Wireless communication is one of the fastest growing segments of the telecommunication industry. With the mobility of the wireless devices, such as cellular phones and pagers, a subscriber to a wireless service can make or receive a call, or receive a message without being restricted to any particular locations. Because of the convenience provided by wireless devices, they have been widely used by average consumers.

Wireless communications are provided through a wireless communication network, which can be realized, for example, as a Signaling System 7 (SS7) network. The SS7 network uses the EIA/TIA Interim Standard 41 (IS-41) protocol, which is the standard commonly used in North America.

The SS7 network is used for switching data messages pertaining to connecting telephone calls and for maintaining the signaling network. As shown in Fig. 1 , the SS7 network 100 has three different types of nodes or signaling points: Service Switching Point (SSP) 112, Signal Transfer Point (STP) 116, and Service Control Point (SCP) 122.

An SSP 112 is an local exchange in the telephone network. An SSP 112 uses the information provided by the calling party (such as dialed digits) and determines how to connect the call. An STP 116 serves as a router in the SS7 network and switches SS7 messages as received from the various SSPs 112 through the network to their appropriate destinations. An STP 116 receives messages in packet form from an SSP 112. These packets are either related to call connections or database queries for an SCP 122. If the packet is a request from an SSP 112 to connect a call, the message must be forwarded to the destination where the call will be terminated. The destination is determined by the dialed digits. If the message is a database query seeking additional information regarding a person who subscribes a wireless service, i.e., a "subscriber", the destination will be a database. Access to telephone company databases is provided through an SCP 122. These databases are used to store information about subscribers' services, calling card validation, fraud protection, etc.

As shown in Fig. 1 , the wireless network is shared by multiple regions 126, such as regions A and B. In each region 126, an SCP 122 is provided. Each region 126 is further divided into a number of registration areas 132, each of which is served by a Mobile Switching Center (MSC) 136. An MSC 136 provides wireless communication services to all properly registered cellular phones 142 in the registration area.

As illustrated in Fig. 1 , an SCP 122 contains an authentication center (AC) 146 and a home location registers (HLR) 152. AC 146 authenticates a subscriber's cellular phone through the use of an encrypted number called the A-Key. HLR 152 is used to store information regarding cellular subscribers in the region for which it provides services. HLR 152 also stores information identifying the services allowed for each subscriber. In addition to these, HLR 152 stores the current locations of cellular phones 142 of those subscriber's who initially activated their cellular phones through a wireless service provider in the region the HLR serves. This region is also referred to as the "home area" of those subscribers. Although not shown, a backup HLR is also provided in SCP 122.

A visitor location register (VLR) 156 is also provided in each region 126. VLR 156 is used when a cellular phone 142 is not recognized by a local MSC. VLR 156 stores the current locations for the visiting subscribers.

Nowadays, subscribers desire to have multiple phone numbers associated with their individual cellular phones. For example, a subscriber may want to have both home number and work number as well as the original cellular phone number associated with his cellular phone. In this way, in an urgent situation, he can be reached by dialing any one of the three phone numbers. This is especially important if someone who tries to reach the subscriber knows only the subscriber's home phone number or his work number but not his cellular phone number.

Moreover, in some countries, such as certain South American countries, the telephone company owns a number of MSCs operating with phone numbers of varying digits. For example, some MSCs may operate with seven-digit numbers, while other MSCs may operate with ten-digit numbers. This creates a problem for a cellular subscriber who roams from his home area to a roaming area where the MSC operates with phone numbers of different length. In such a case, the cellular phone may not be operable in the roaming area. This will cause significant inconvenience to the subscribers who do not know where they cannot receive calls. A subscriber can find out whether he can make a call by simply attempting to do so, but generally a subscriber cannot find out whether he can or cannot receive a call.

Accordingly, there is a need for an improved HLR that can associate multiple phone numbers, even though they may have varying digits, to a single cellular phone. Furthermore, the related phone numbers must be manageable in a single record file in the HLR, so that less resources may be required. Additional attributes may be associated with individual phone numbers associated with a cellular phone so that the phone may ring one way (e.g., two rings) when a particular number (e.g., home number) is dialed and ring another way (e.g., three rings) when another number (e.g., work number) is dialed.

SUMMARY OF THE INVENTION

The present invention provides an improved home location register (HLR) that implements alias mobile ID numbers (MIN) in a mobile telephone system. According to the invention, the improved HLR includes an alias MIN module that comprises an alias MIN table and an alias MIN application program. The alias MIN table associates multiple phone numbers of a cellular phone to the cellular phone's preprogrammed MIN. When the HLR receives dialed digits from an MSC in a location request, the application program uses the dialed digits as key to locate the associated MIN of the receiving party's cellular phone. The retrieved MIN is then included in the routing message and forwarded to the appropriate MSC that currently serves the receiving party's cellular phone. In this way, the subscriber can be reached by dialing any of the pre-associated phone numbers. Therefore, significant convenience is provided to cellular subscribers.

Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 depicts a typical SS7 communication network;

Fig. 2 shows an example of an HLR according to the invention;

Fig. 3 shows a partial format of a subscriber's profile in a SUBS file of an HLR according to the invention;

Fig. 4 shows an example format of an alias MIN table according to the invention;

Fig. 5 shows a call delivery flow diagram when the receiving party's cellular phone is in its home area;

Fig. 6 shows a call delivery flow diagram when the receiving party's cellular phone is outside its home area in a roaming area; and

Fig. 7 shows a flow chart of the alias MIN module according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Fig. 2 shows home location register (HLR) 200 according to the invention. As shown, HLR 200 comprises conventional HLR components 212, MPCM file 216, SUBS file 222 and alias MIN (Mobile ID Number) module 226. MPCM file 216 is the "MSC ID Point Code Map File" which store MSCs' network configuration information. Each MSC communicating to an HLR has a corresponding MPCM file record stored in the MPCM file of the HLR. SUBS file 222 is the "subscribers' file" which stores subscribers' profiles on a per subscriber basis (i.e., information for each cellular phone). Usually one SUBS file contains information about all of its home subscribers (i.e. the subscribers who initially activated their cellular phones in the region the HLR serves). Alias MIN module 226 includes an alias MIN table 232 and an alias MIN application program 236. It will be understood by persons of ordinary skill in the art that functions performed by the HLR are implemented by a processor executing computer instructions stored in a memory.

Fig. 3 shows a partial format of a subscriber's profile in SUBS file 222. There are several segments in each subscriber's profile record of the SUBS file, including the BASE_REC_INFO, SHAREDJNFO, TRANSIENTJNFO, etc. Each segment includes multiple fields. The BASE_RECJNFO segment contains information needed by IS-41 applications to access a subscriber record. This segment includes the R_MIN_KEY, ESN fields, etc. The R_MIN_KEY field is the subscriber file's primary key. It contains the subscriber's MIN (Mobile ID Number) stored in reverse byte order. The ESN field is the subscriber file's alternate key. It contains the Equipment Serial Number (ESN) associated with the subscriber's MIN.

The SHARED-INFO segment of a subscriber's profile record stores attributes common to the IS-41 applications. This segment includes the HOME MSCID, SHARED_ACCESS_MAP, AUTH_ENABLED fields, etc. The HOMEJvlSCID field identifies the ID number of the MSC that is in the subscriber's home area. The SHARED_ACCESS_MAP field is a bitmap identifying the IS-41 applications currently accessing the subscriber's data. The AUTHJΞNABLED field identifies whether or not authentication is enabled and should be performed for this subscriber.

The TRANSIENTJNFO segment of a subscriber's profile stores the registration information about this subscriber. The segment includes the VLR_MSCID, REG_STATUSJND fields, etc. the VLR_MSCID field identifies the MSCID of the VLR in a roaming area where the subscriber is currently registered. The REG_STATUSJND field identifies the subscriber's registration status. The field stores the information relating to, e.g., whether the subscriber is registered, whether registration is active in the home area, and whether the registration is active in the roaming area.

Fig. 4 shows an example format of alias MIN table 232 of the invention. In this table, the dialed digits, i.e., the dialed phone number, are the primary key for locating the associated MIN of the cellular phone which is being called. The associated MIN is stored in the cellular phone when the phone is activated by a wireless service provider and cannot be changed. As illustrated, subscriber A has m phone numbers associated with his cellular phone. Subscriber B has n phone numbers associated with her cellular phone. And subscriber N has w phone numbers associated with his cellular phone. These multiple phone numbers are also referred to as the "alias MINs" of the respective cellular phones. In a preferred embodiment of the invention, the number of phone numbers that can be associated with a single cellular phone can range from 1 to 20 depending on the subscriber's choice. For example, a subscriber may want to have both home number and work number as well as the original cellular phone number associated with his cellular phone so that he can be reached by calling any of the three numbers. In this way, three phone numbers are associated with the MIN programmed in his cellular phone.

The present invention can be best understood by the working examples described below.

Fig. 5 illustrates how call delivery is made to an idle cellular phone currently located in its home area. As illustrated, an SCP 502 and a VLR 526 are provided in a home area 506 of a cellular phone 508. SCP 502 includes AC 516 and HLR 522. When a calling party places a call to a receiving party, a call origination and the dialed digits (i.e., the directory number) are received by MSC 532 at step 552. Then, at step 556, MSC 532 sends a location request (LOCREQ) message containing the dialed digits (DGTSDIAL) to HLR 522 in home area 506. Upon receiving the dialed digits, the alias MIN application program of HLR 522 accesses the alias MIN table (such as shown in Fig. 4), using the dialed digits as the key to find the associated MIN of the receiving party's cellular phone. After having found the associated MIN, the application program uses this MIN to access the receiving party's profile in the SUBS file (within the HLR) to determine if the receiving party is a legitimate subscriber. If the receiving party is a legitimate subscriber and the receiving party is determined as being currently served by MSC 532 based on the current location of the receiving party's cellular phone stored in his profile, HLR 522 sends a locreq response to MSC 532 at step 562. The locreq response contains routing information which includes the MSCID (MSC Identification) of the MSC serving the receiving party. Upon receiving the locreq response, MSC 532 recognizes itself as the serving MSC via the MSCID parameter in the locreq response, and then attempts to deliver the call to the receiving party's cellular phone identified in the locreq response at step 566.

Fig. 6 illustrates how call delivery is made to a cellular phone that is outside its home area 612 in a roaming area 616. Home area 612 and roaming area 616 correspond to two regions, such as regions A and B, respectively, shown in Fig. 1. In home area 612, an SCP 622 and a VLR 642 are provided. SCP 622 includes an AC 632 and an HLR 636. An MSC 643 is also located in home area 612. In roaming area 616, an SCP 644 and a VLR 656 are provided. SCP 644 includes an AC 646 and an HLR 652. An MSC 658 is also located in roaming area 616. In Fig. 6, although MSCs are shown as separate entities from the HLR and VLR in the respective areas, in a real application the HLRΛ LR functions may be integrated with the MSCs.

As shown in Fig. 6, when a calling party places a call to a receiving party, a call origination and the dialed digits are received by originating MSC 643 at step 662. MSC 643 is thus also referred to as an originating MSC. Then, at step 664, originating MSC 643 sends a location request (LOCREQ) message containing the dialed digits to HLR 636 in home area 612. Steps 662 and 664 are the same as steps 552 and 556 illustrated in Fig. 5. Upon receiving the dialed digits, the alias MIN application program in the alias MIN module of HLR 636 accesses the alias MIN table (as shown in Fig. 3) using the dialed digits as the key to find the associated MIN for the receiving party's cellular phone. Then the application program uses the associated MIN as the key to access the receiving party's profile in the SUBS file to determine if the receiving party is a legitimate subscriber. If the dialed digits are assigned to a legitimate subscriber, at step 668, HLR 636 sends a routing address request (ROUTREQ) message to VLR 656 in roaming area 616 where the receiving party's cellular phone is currently registered. The current location information about the receiving party's cellular phone was sent to HLR 636 by VLR 656 after the receiving party arrived in the roaming area and the cellular phone registered with VLR 652. The ROUTREQ message contains the associated MIN of the receiving party's cellular phone. VLR 656 then forwards the ROUTREQ to MSC 658 currently serving the receiving party's cellular phone at step 670. MSC 658 is also referred to as a serving MSC. In response to the ROUTREQ, serving MSC 658 consults its internal data structures to determine if the receiving party's cellular phone is already engaged in a call on this MSC. Assuming that the cellular phone is not known to serving MSC 658, serving MSC 658 may then obtain the receiving party's profile from its VLR 656 by sending it a qualification request (QUALREQ) message at step 672. Step 672 can be eliminated if the receiving party's profile has already been obtained by serving MSC 658 prior to the call delivery attempt (e.g., at the time the receiving party's cellular phone registered in the registration area served by MSC 658). If the receiving party's cellular phone is unknown to VLR 656 or if the information requested is not available at VLR 656, VLR 656 sends the QUALREQ message to HLR 636 in home area 612 at step 674. HLR 636 then sends a qualreq response to VLR 656 at step 678. The qualreq response contains relevant information about the receiving party's profile. VLR 656 in turn sends the qualreq response to serving MSC 658 at step 680. Upon receiving the qualreq, serving MSC 658 allocates a temporary identifier TLDN (Temporary Local Directory Number) and returns this information to VLR 656 in the routreq message at step 682. VLR 656 in turn sends the routreq message to HLR 636 at step 684. When the routreq message is received by HLR 636, it returns a locreq response to originating MSC 643 at step 686. The locreq response includes routing information which includes the MSCID of serving MSC 658 and the TLDN. Finally, originating MSC 643 establishes a voice path to serving MSC 658 using existing interconnection protocols (e.g., SS7) and the routing information specified in the locreq response, as illustrated at step 688.

Fig. 7 shows a flow chart illustrating the operation of alias MIN application program 236 of the HLR. As described above, the home area of a subscriber's cellular phone refers to the region such as region A or B shown in Fig. 1 where the subscriber initially activates his cellular phone through a wireless service provider he has selected in that region. In this example, assume that the subscriber is being called by someone. The steps of Fig. 6 may be performed by HLR 522 of Fig. 5 or HLR 636 of Fig. 6 (although HLR 652 of Fig. 6 also has this capability under other circumstances). In Fig. 7, after an origination request with the dialed digits is received by an MSC in the home area of the receiving party's cellular phone, the MSC sends a location request with the dialed digits to the HLR in that home area to attempt to reach the MSC currently serving the receiving party's cellular phone, as illustrated by step 712. At step 716, application program 236 reads alias MIN table 232 within the HLR, using the dialed digits as the key to locate the associated MIN of the receiving party's cellular phone. At step 722, application program 236 uses the MIN retrieved from the alias MIN table as the key to access the SUBS file 222 to locate the receiving party's profile. Then, from the receiving party's profile, application program 236 determines whether the receiving party is a legitimate subscriber at step 726. If he is not a legitimate subscriber, application program 236 sends a denied message to the MSC at step 732. On the other hand, if the receiving party is a legitimate subscriber, at step 736, application program 236 sends an approval signal to the conventional HLR components 212 which then send the routing information to the appropriate MSC that currently serves the receiving party's cellular phone. The routing information includes the MIN retrieved from the alias MIN table. Then, application program 236 exits at step 742. In this way, one may simply dial any one of the three numbers, for example, the subscriber's work number, to reach the subscriber. The caller need not to know the subscriber's original cellular phone number or his home number.

While the invention has been described in conjunction with specific embodiments, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and scope of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A method for implementing alias mobile ID numbers (MINs) in a home location register (HLR) for a mobile telephone system, the method comprising the steps of : pre-associating a plurality of phone numbers with a programmed MIN of each of individual cellular phones of pre-selected subscribers; receiving dialed digits from a mobile switching center (MSC); and retrieving a corresponding MIN based on the dialed digits received form the

MSC.

2. The method of claim 1 , further comprising the steps of: determining whether a subscriber having a cellular phone with the corresponding MIN is a legitimate subscriber; and providing the corresponding MIN in a routing message to an MSC currently serving the subscriber's cellular phone with the corresponding MIN.

3. The method of claim 2, further comprising the step of sending a denied message to the MSC if the subscriber is not a legitimate subscriber.

4. A home location register (HLR), comprising: a first portion configured to pre-associate a plurality of phone numbers with a programmed MIN of each of individual cellular phones of pre-selected subscribers; a second portion configured to receive dialed digits from a mobile switching center (MSC); and a third portion configured to retrieve a corresponding MIN based on the dialed digits received from the MSC.

5. The HLR of claim 4, further comprising: a fourth portion configured to determine whether a subscriber having a cellular phone with the corresponding MIN is a legitimate subscriber; and a fifth portion configured to provide the corresponding MIN in a routing message to an MSC currently serving the subscriber's cellular phone with the corresponding MIN.

6. The HLR of claim 5, further comprising: a sixth portion configured to send a denied message to the MSC if the subscriber is not a legitimate subscriber.

7. A computer program product, comprising: a computer usable medium having computer readable code embodied therein for implementing alias mobile ID numbers (MINs) in a home location register (HLR) for a mobile telephone system, the computer program product comprising: computer readable program code devices configured to cause a computer to effect pre-associating a plurality of phone numbers with a programmed MIN of each of individual cellular phones of pre-selected subscribers; computer readable program code devices configured to cause a computer to effect receiving dialed digits from a mobile switching center (MSC); and computer readable program code devices configured to cause a computer to effect retrieving a corresponding MIN based on the dialed digits received form the MSC.

8. The computer program product of claim 7, further comprising: computer readable program code devices configured to cause a computer to effect determining whether a subscriber having a cellular phone with the corresponding MIN is a legitimate subscriber; and computer readable program code devices configured to cause a computer to effect providing the corresponding MIN in a routing message to an MSC currently serving the subscriber's cellular phone with the corresponding MIN.

9. The computer program product of claim 8, further comprising computer readable program code devices configured to cause a computer to effect sending a denied message to the MSC if the subscriber is not a legitimate subscriber.