Method and apparatus for system acquisition in a mobile communication terminal

• US 8,504,095 B2
• Filed: 10/04/2007
• Issued: 08/06/2013
• Est. Priority Date: 10/31/2006
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Joo, Jae Seok
• Primary Examiner(s): SIVJI, NIZAR N
• Application Number:
  US11/867,449
• Publication Number:
  US 20080102825A1
• Time in Patent Office: 2,133 Days
• Field of Search: 455/452, 455/528, 455434-435, 455/457, 342/357.2
• US Class Current: 455/550.1
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service

Abstract

A method and an apparatus are provided for acquiring, in a reduced time, a system using location information in a mobile communication terminal. When a mobile communication terminal is turned on or disconnects with a base station, a Preferred Roaming List (PRL) is searched in order of closeness of a system to the current location of the mobile communication terminal. At predetermined time intervals, the systems of the PRL are arrayed in order of closeness of a system to the current location, and the arrayed PRL is searched. The present invention can reduce the time taken to acquire a system.

Claims

1. An apparatus for acquiring a system in a mobile communication terminal, the apparatus comprising:

a Radio Frequency (RF) communication unit for transmitting and receiving a radio frequency signal;

a location signal receiver for receiving a location signal;

a system list storage unit for storing a system list to be searched for acquiring a system;

a system list management unit that arrays the system list stored in the system list storage unit based on location signals received by the location signal receiver;

a timer that starts at a predetermined time interval to indicate elapse of the predetermined time duration; and

a control unit for acquiring the system by searching the system list stored in the system list storage unit for a closest system to a current calculated location of the mobile communication terminal from the location signal received by the location signal receiver,

wherein the control unit arrays the system list in order of geographical closeness of the systems to the current calculated location based on the received location signal, and searches the system list in order of the arrayed system list,

wherein the system list includes a Most Recently Used (MRU) list and a Preferred Roaming List (PRL), which include coordinate information of a system location, and

wherein the control unit starts the timer upon transforming the state of the mobile communication terminal into the idle state, and controls the system list management unit to array, upon elapse of the predetermined time duration, the system list stored in the system list storage unit in the order of closeness of systems to the current calculated location.

2. The apparatus of claim 1, wherein the location signal receiver receives location information from a Global Positioning System (GPS) satellite, including an almanac and an ephemeris.

3. The apparatus of claim 1, wherein the control unit searches the MRU list upon turning on the mobile communication terminal.

4. The apparatus of claim 3, wherein the control unit searches, if a system is not acquired by searching the MRU list, the PRL in an order of closeness of systems to the current calculated location based on the location signal received by the location signal receiver and coordinate information of the system in the PRL.

5. The apparatus of claim 1, wherein the control unit transforms the state of the mobile communication terminal into the idle state upon acquiring a system by searching the MRU list.

6. The apparatus of claim 1, wherein the control unit controls, if a system is not acquired by searching the MRU list, the system list management unit to array the system list stored in the system list storage unit in the order of closeness of systems to the current calculated location based on the location signal received by the location signal receiver and coordinate information of the systems in the PRL, and to search the systems by the arrayed order.

7. The apparatus of claim 1, wherein the control unit searches the MRU list upon disconnecting with a base station, and searches, if a system is not acquired by searching the MRU list, the PRL.

8. The apparatus of claim 7, wherein the control unit searches, if a system is not acquired by searching the MRU, the PRL in order of closeness of systems to the current calculated location based on the location signal received by the location signal receiver and coordinate information of the system in the PRL.

9. The apparatus of claim 7, wherein the control unit transforms the state of the mobile communication terminal into the idle state if a system is acquired by searching the MRU list.

10. The apparatus of claim 8, wherein the control unit transforms a state of the mobile communication terminal into an idle state if a system is acquired by searching the PRL.

11. A method for acquiring a system in a mobile communication terminal, the method comprising:

searching, upon turning on the mobile communication terminal, systems that were used most recently;

calculating, if a system is not acquired by searching the most recently used systems, a current location of the mobile communication terminal;

arraying, by a system list management unit, a system list stored in a system list storage unit, based on location signals received by a location signal receiver, in order of geographical closeness of the system to the calculated current location based on the current location of the mobile communication terminal;

searching systems in order of the arrayed system list;

transforming, if a system is acquired by searching the systems, a state of the mobile communication terminal into an idle state; and

running a timer at a predetermined time interval to indicate elapse of a predetermined time duration in the idle state of the mobile communication terminal,

wherein the system list includes a Most Recently Used (MRU) list and a Preferred Roaming List (PRL), which include coordinate information of a system location, and

wherein a control unit starts the timer upon transforming the state of the mobile communication terminal into the idle state, and controls the system list management unit to array, upon elapse of the predetermined time duration, the system list stored in the system list storage unit in the order of closeness of systems to the current calculated location.

12. The method of claim 11, wherein searching systems in the order of the arrayed system list comprises:

arraying the Preferred Roaming List (PRL) in order of closeness of the systems to the calculated current location; and

searching the systems in order of the arrayed PRL.

13. The method of claim 11, wherein, in searching systems that were used most recently, the systems are searched in an order of closeness to a calculated current location based on coordinate information of the system location.

14. The method of claim 11, further comprising:

calculating, upon elapse of the predetermined time duration, the current location.

15. A method for acquiring a system in a mobile communication terminal, comprising:

searching, upon disconnecting from a base station, systems that were used most recently;

searching, if a system is not acquired by searching the most recently used systems, systems to be roamed;

calculating, if a system is not acquired by searching the systems to be roamed, a current location of the mobile communication terminal;

arraying, by a system list management unit, a system list stored in a system list storage unit, based on location signals received by a location signal receiver, in order of geographical closeness of the system to the calculated current location based on the current location of the mobile communication terminal;

searching systems in an order of the arrayed system list;

transforming, if a system is acquired, a state of the mobile communication terminal into an idle state; and

running a timer at a predetermined time interval to indicate elapse of a predetermined time duration in the idle state of the mobile communication terminal,

wherein the system list includes a Most Recently Used (MRU) list and a Preferred Roaming List (PRL), which include coordinate information of a system location, and

wherein a control unit starts the timer upon transforming the state of the mobile communication terminal into the idle state, and controls the system list management unit to array, upon elapse of the predetermined time duration, the system list stored in the system list storage unit in the order of closeness of systems to the current calculated location.

16. The method of claim 15, further comprising:

calculating, upon elapse of the predetermined time duration, the current location.

17. The method of claim 15, wherein searching systems in the order of the arrayed system list comprises:

arraying the Preferred Roaming List (PRL) in order of closeness of a system to the calculated current location; and

searching the systems in order of the arrayed PRL.

18. The method of claim 17, wherein the PRL includes coordinate information of the system location.

19. The method of claim 15, wherein, when searching of systems to be roamed, the systems to be roamed are arrayed according to a last calculated location prior to disconnection with a base station.