Apparatus of public land mobile network selection and method of the same

• US 20050153722A1
• Filed: 12/03/2004
• Published: 07/14/2005
• Est. Priority Date: 12/05/2003
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Chou, Ming-Ying, Lin, Sung-Yao
• Granted Patent: US 7,383,054 B2
• Time in Patent Office: Days
• US Class Current: 455/512
• CPC Class Codes: H04W 48/10 using broadcasted information
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service

Abstract

A method and an apparatus for selecting a public land mobile network (PLMN) for a mobile station are provided. The method and the apparatus according to this invention use the first and the second system information included in the broadcasting information broadcasted by a base station to find out all of the base stations belonging to the same PLMN as that base station in the base station table, and group those base stations belonging to the same PLMN as a base station group. The method and the apparatus according to this invention only need to synchronize with one base station in a base station group, and the other base stations belonging to the same base station group as that base station are known. Accordingly, the selection method according to this invention can substantially reduce the time for selecting a PLMN and improve the corresponding efficiency.

Claims

1. A method for selecting a public land mobile network (PLMN), said method being applied in a mobile station, wherein it is suitable for the mobile station to select one among M PLMNs to be a serving PLMN for providing communication services, and M is a natural number, said method comprising the following steps of:

(a) receiving N pieces of broadcasting information broadcasted by N base stations respectively and measuring power values of broadcasting information corresponding to the N base stations, wherein N is a natural number;

(b) establishing a base station table for recording N sets of information, each set of information being corresponding to one base station among the N base stations, each set of information comprising a measured power value, a base station code, and a PLMN code corresponding to one of the N base stations, the N sets of information being recorded in the base station table in sequence according to the magnitudes of the N power values of broadcasting information, wherein the base station corresponding to the first set of information in the sequence is called as a first base station, the base station corresponding to the second set of information in the sequence is called as a second base station, and the base station corresponding to the Nth set of information in the sequence is called as a Nth base station;

(c) setting the initial value of an integer index i as one;

(d) selecting an ith priority PLMN as a target PLMN;

(e) setting the initial value of an integer index j as one;

(f) selecting the jth base station among the N base stations as a candidate base station;

(g) according to the PLMN code corresponding to the candidate base station recorded in the base station table, determining whether the PLMN to which the candidate base station belongs is known, if the result of step (g) is YES, then executing step (j), if the result of step (g) is NO, then executing step (h);

(h) synchronizing the mobile station with the candidate base station and reading the broadcasting information broadcasted by the candidate base station;

(i) updating the value in a PLMN field of the base station table;

(j) according to the PLMN code corresponding to the candidate base station recorded in the base station table, determining whether the candidate base station belongs to the target PLMN, if the result of step (j) is YES, then executing step (k), if the result of step (j) is NO, then executing step (l);

(k) selecting the ith priority PLMN as the serving PLMN that provides communication services to the mobile station;

(l) setting j=j+1;

(m) determining whether j is larger than N, if the result of step (m) is YES, then executing step (n), if the result of step (m) is NO, then returning back to step (f);

(n) setting i=i+1;

(o) determining whether i is larger than M, if the result of step (o) is YES, then executing step (p), if the result of step (o) is NO, then returning back to step (d); and

(p) terminating said method.

2. The method of claim 1, wherein the mobile station is a mobile phone or a PDA.

3. The method of claim 1, wherein the broadcasting information comprises a first system information (SI1), a second system information (SI2), and a third system information (SI3).

4. The method of claim 3, wherein step (i) comprises the following sub-steps of:

(i1) according to the third system information in the broadcasting information broadcasted by the candidate base station, updating the PLMN code corresponding to the candidate base station in the base station table; and

(i2) according to the first system information and the second system information in the broadcasting information broadcasted by the candidate base station, finding out in the base station table the base stations that belongs to the same PLMN as the candidate base station, and updating the PLMN codes corresponding to the base stations, which belongs to the same PLMN as the candidate base station, in the base station table.

5. The method of claim 1, wherein the first priority PLMN is the registered public land mobile network (RPLMN) for the mobile station.

6. The method of claim 1, wherein the second priority PLMN is the home public land mobile network (HPLMN) for the mobile station.

7. The method of claim 1, wherein in step (k), the method selects the jth base station as the base station that provides communication services to the mobile station.

8. A mobile station for selecting a public land mobile network (PLMN), wherein it is suitable for the mobile station to select one among M PLMNs to be a serving PLMN, and M is a natural number, said apparatus comprising:

a receiving module for receiving ten pieces of broadcasting information broadcasted by N base stations respectively and measuring the power values of broadcasting information corresponding to the N base stations, wherein N is a natural number;

an establishing module for establishing a base station table for recording N sets of information, each set of information being corresponding to one base station among the N base stations, each set of information comprising a measured power value, a base station code, and a PLMN code corresponding to one base station among the N base stations, the N sets of information being recorded in the base station table in sequence according to the magnitudes of the N power values of broadcasting information, wherein the base station corresponding to the first set of information in the sequence is called as a first base station, the base station corresponding to the second set of information in the sequence is called as a second base station, and the base station corresponding to the Nth set of information in the sequence is called as a Nth base station;

a first setting module for setting the initial value of an integer index i as one;

a first selecting module for selecting an ith priority PLMN as a target PLMN;

a second setting module for setting the initial value of an integer index j as one;

a second selecting module for selecting the jth base station among the N base stations as a candidate base station;

a first determining module for determining whether the PLMN to which the candidate base station belongs is known according to the PLMN code corresponding to the candidate base station recorded in the base station table;

a synchronizing module operating based on the determined result of the first determining module, if the determined result of the first determining module is NO, then the synchronizing module synchronizing the mobile station with the candidate base station and reading the broadcasting information broadcasted by the candidate base station;

an updating module for updating the value in a PLMN field of the base station table according to the broadcasting information read by the synchronizing module;

a second determining module for determining whether the candidate base station belongs to the target PLMN according to the PLMN code corresponding to the candidate base station recorded in the base station table;

a third selecting module operating based on the determined result of the second determining module, if the determined result of the second determining module is YES, then the third selecting module selecting the ith priority PLMN as the serving PLMN that provides communication services to the mobile station;

a third setting module operating based on the determined result of the second determining module, if the determined result of the second determining module is NO, then the third setting module setting j=j+1;

a third determining module for determining whether j, which is set by the third setting module, is larger than N, if the determined result of the third determining module is NO, then the j, which is set by the third setting module, being transferred to the second selecting module;

a fourth setting module operating based on the determined result of the third determining module, if the determined result of the third determining module is YES, then the fourth setting module setting i=i+1;

a fourth determining module for determining whether i, which is set by the fourth setting module, is larger than M, if the determined result of the fourth determining module is NO, then the i, which is set by the fourth setting module, is transferred to the first selecting module; and

a terminating module operating based on the determined result of the fourth determining module, if the determined result of the fourth determining module is YES, then the terminating module terminating the operation of said apparatus.

9. The mobile station of claim 8, wherein the mobile station is a mobile phone or a PDA.

10. The mobile station of claim 8, wherein the broadcasting information comprises a first system information (SI1), a second system information (SI2), and a third system information (SI3).

11. The mobile station of claim 10, wherein the updating module updates the PLMN code corresponding to the candidate base station in the base station table according to the third system information in the broadcasting information broadcasted by the candidate base station, finds out in the base station table the base stations that belongs to the same PLMN as the candidate base station according to the first system information and the second system information in the broadcasting information broadcasted by the candidate base station, and then updates the PLMN codes corresponding to the base stations, which belongs to the same PLMN as the candidate base station, in the base station table.

12. The mobile station of claim 8, wherein the first priority PLMN is the registered public land mobile network (RPLMN) for the mobile station.

13. The mobile station of claim 8, wherein the second priority PLMN is the home public land mobile network (HPLMN) for the mobile station.

14. The mobile station of claim 8, wherein if the determined result of the second determining module is YES, then the third selecting module selects the jth base station as the serving base station that provides communication services to the mobile station.

15. A computer program product comprising a storage medium, the storage medium having an embedded computer program for selecting a public land mobile network (PLMN) for a mobile station, wherein it is suitable for the mobile station to select one among M PLMNs to be a serving PLMN for providing communication services, and M is a natural number, when being executed by the mobile station, the computer program making the mobile station perform the following steps of:

(a) receiving N pieces of broadcasting information broadcasted by N base stations respectively and measuring power values of broadcasting information corresponding to the N base stations, wherein N is a natural number;

(b) establishing a base station table for recording N sets of information, each set of information being corresponding to one base station among the N base stations, each set of information comprising a measured power value, a base station code, and a PLMN code corresponding to one of the N base stations, the N sets of information being recorded in the base station table in sequence according to the magnitudes of the N power values of broadcasting information, wherein the base station corresponding to the first set of information in the sequence is called as a first base station, the base station corresponding to the second set of information in the sequence is called as a second base station, and the base station corresponding to the Nth set of information in the sequence is called as a Nth base station;

(c) setting the initial value of an integer index i as one;

(d) selecting an ith priority PLMN as a target PLMN;

(e) setting the initial value of an integer index j as one;

(f) selecting the jth base station among the N base stations as a candidate base station;

(g) according to the PLMN code corresponding to the candidate base station recorded in the base station table, determining whether the PLMN to which the candidate base station belongs is known, if the result of step (g) is YES, then executing step (j), if the result of step (g) is NO, then executing step (h);

(h) synchronizing the mobile station with the candidate base station and reading the broadcasting information broadcasted by the candidate base station;

(i) updating the value in a PLMN field of the base station table;

(j) according to the PLMN code corresponding to the candidate base station recorded in the base station table, determining whether the candidate base station belongs to the target PLMN, if the result of step (k) is YES, then executing step (k), if the result of step (j) is NO, then executing step (l);

(k) selecting the ith priority PLMN as the serving PLMN that provides communication services to the mobile station;

(l) setting j=j+1;

(m) determining whether j is larger than N, if the result of step (m) is YES, then executing step (n), if the result of step (m) is NO, then returning back to step (f);

(n) setting i=i+1;

(o) determining whether i is larger than M, if the result of step (o) is YES, then executing step (p), if the result of step (o) is NO, then returning back to step (d); and

(p) terminating said computer program.

16. The computer program product of claim 15, wherein the mobile station is a mobile phone or a PDA.

17. The computer program product of claim 15, wherein the broadcasting information comprises a first system information (SI1), a second system information (SI2), and a third system information (SI3).

18. The computer program product of claim 17, wherein step (i) comprises the following sub-steps of:

(i1) according to the third system information in the broadcasting information broadcasted by the candidate base station, updating the PLMN code corresponding to the candidate base station in the base station table; and

(i2) according to the first system information and the second system information in the broadcasting information broadcasted by the candidate base station, finding out in the base station table the base stations that belongs to the same PLMN as the candidate base station, and updating the PLMN codes corresponding to the base stations, which belongs to the same PLMN as the candidate base station, in the base station table.

19. The computer program product of claim 15, wherein the first priority PLMN is the registered public land mobile network (RPLMN) for the mobile station.

20. The computer program product of claim 15, wherein the second priority PLMN is the home public land mobile network (HPLMN) for the mobile station.

21. The computer program product of claim 15, wherein in step (k), the computer program selects the jth base station as the serving base station that provides communication services to the mobile station.

22. A method for obtaining at least one public land mobile network (PLMN) code corresponding to at least one base station, said method being applied in an electronic apparatus and comprising the following steps of:

receiving N pieces of broadcasting information broadcasted by N base stations respectively and measuring power values of broadcasting information corresponding to the N base stations, wherein N is a natural number;

selecting one base station among the N base stations, the selected base station having a larger power value of broadcasting information and being called as a first base station; and

reading the broadcasting information broadcasted by the first base station, obtaining the PLMN code corresponding to the first base station, and finding out at least one base station, which belongs to the same PLMN as the first base station and is called as a second base station, corresponding to which the PLMN code is known.

23. The method of claim 22, wherein the electronic system is a mobile phone or a PDA.

24. The method of claim 22, wherein the broadcasting information comprises a first system information (SI1), a second system information (SI2), and a third system information (SI3).

25. The method of claim 23, wherein the PLMN code corresponding to the first base station is obtained by reading the third system information included in the broadcasting information broadcasted by the first base station, the second base station is found out by reading the first and the second system information included in the broadcasting information broadcasted by the first base station.

26. An electronic apparatus for obtaining at least one public land mobile network (PLMN) code corresponding to at least one base station, comprising:

a receiving module for receiving N pieces of broadcasting information broadcasted by N base stations respectively and measuring power values of broadcasting information corresponding to the N base stations, wherein N is a natural number;

a selecting module for selecting one base station among the N base stations, the selected base station having a larger power value of broadcasting information and being called as a first base station; and

a reading module for reading the broadcasting information broadcasted by the first base station, obtaining the PLMN code corresponding to the first base station, and finding out at least one base station, which belongs to the same PLMN as the first base station and is called as a second base station, corresponding to which the PLMN code is known.

27. The electronic apparatus of claim 26, wherein the electronic apparatus is a mobile phone or a PDA.

28. The electronic apparatus of claim 26, wherein the broadcasting information comprises a first system information (SI1), a second system information (SI2), and a third system information (SI3).

29. The electronic apparatus of claim 28, wherein the PLMN code corresponding to the first base station is obtained by reading the third system information included in the broadcasting information broadcasted by the first base station, the second base station is found out by reading the first and the second system information included in the broadcasting information broadcasted by the first base station.

30. A computer program product comprising a storage medium, the storage medium having an embedded computer program for obtaining at least one PLMN code corresponding to at least one base station, when the computer program being executed by an electronic apparatus, the computer program making the electronic apparatus perform the following steps of:

receiving N pieces of broadcasting information broadcasted by N base stations respectively and measuring power values of broadcasting information corresponding to the N base stations, wherein N is a natural number;

selecting one base station among the N base stations, the selected base station having a larger power value of broadcasting information and being called as a first base station; and

reading the broadcasting information broadcasted by the first base station, obtaining the PLMN code corresponding to the first base station, and finding out at least one base station, which belongs to the same PLMN as the first base station and is called as a second base station, corresponding to which the PLMN code is known.

31. The computer program product of claim 30, wherein the electronic apparatus is a mobile phone or a PDA.

32. The computer program product of claim 30, wherein the broadcasting information comprises a first system information (SI1), a second system information (SI2), and a third system information (SI3).

33. The computer program product of claim 32, wherein the PLMN code corresponding to the first base station is obtained by reading the third system information of the broadcasting information broadcasted by the first base station, the second base station is found out by reading the first and the second system information of the broadcasting information broadcasted by the first base station.