Radio telephone apparatus having a service area confirmation

• US 5,444,765 A
• Filed: 04/18/1994
• Issued: 08/22/1995
• Est. Priority Date: 03/23/1992
• Status: Expired due to Term

• Current Assignee: Fujitsu Mobile Communications Limited (Fujitsu Limited)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Takahashi, Shinya, Hattori, Kiyoshi, Marui, Kuniyoshi
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): OEHLING, GEORGE J
• Application Number:
  US08/229,093
• Time in Patent Office: 491 Days
• Field of Search: 379/58, 379/59, 379/60, 379/63, 455/33.1, 455/33.2, 455/54.2
• US Class Current: 455/432.1
• CPC Class Codes: H04W 8/183 Processing at user equipment or user record carrier

Abstract

A radio telecommunication apparatus includes a storage for storing a system identification data of a system to which the apparatus belongs to and provides an indication relating to where the apparatus is present on the basis of a result of a comparison between the system identification data stored in the storage and a system identification data received through a control channel which is established immediately before a speech communication link is established. According to the present invention, even if the user'"'"'s apparatus moves, at the time of calling, from the home area to the roam area or from the roam area to the home area, the area confirmation data corresponding to the current position of the apparatus is accurately displayed.

Claims

1. A cellular radio telephone for use in a plurality of cellular radio systems, each having one or more base stations that broadcast radio signals throughout a service area over a paging channel and over an access channel, the radio signals including system identification data identifying the cellular radio system from which the radio signals are broadcast, said cellular radio telephone comprising:

storing means for storing system identification data of one of said cellular radio systems to establish said one cellular radio system as a home cellular radio system and to establish a service area throughout which said home cellular radio system broadcasts as a home service area;

establishing means for establishing a paging channel with a cellular radio system in whose service area said cellular radio telephone is then present in response to power-up of said cellular radio telephone and for establishing an access channel with a cellular radio system in whose service area said cellular radio telephone is then present in response to an input of call placement request by a user;

detecting means coupled to said establishing means for detecting system identification data from the radio signals broadcast over said established paging channel by said cellular radio telephone system in whose service area said cellular radio telephone is present at power-up of said cellular radio telephone and for detecting system identification data from the radio signals broadcast over said established access channel by said cellular radio telephone system in whose service area said cellular radio telephone is present at the input of the call placement request;

comparing means, coupled to said detecting means and said storing means, for comparing the system identification data detected from the radio signals broadcast over said established paging channel with the stored system identification data and for comparing the system identification data detected from the radio signals broadcast over said established access channel with the stored system identification data; and

indication means, coupled to the comparing means, for providing an indication of roamer status if the system identification data detected from the radio signals broadcast over said established paging channel does not coincide with the stored system identification data and for providing an indication of roamer status if the system identification detected from the radio signals broadcast over said established access channel does not coincide with the stored system identification data.

2. The cellular radio telephone of claim 1, wherein said indication means eliminates the provided indication of roamer status if the system identification data subsequently detected from the radio signals broadcast over said established access channel coincides with the stored system identification data.

3. The cellular radio telephone of claim 1, wherein said indication means provides an indication of home area user status if the system identification data detected from the radio signals broadcast over said established paging channel coincides with the stored system identification data.

4. The cellular radio telephone of claim 3, wherein said indication means eliminates the provided indication of home area user status if the system identification data subsequently detected from the radio signals broadcast over said established access channel does not coincide with the stored system identification data.

5. The cellular radio telephone of claim 1, wherein said indication means provides an indication of home area user status if the system identification data detected from the radio signals broadcast over said established access channel coincides with the stored system identification data.

6. The cellular radio telephone of claim 1, further comprising a console unit having a call request key, and wherein said establishing means establishes the access channel with said cellular radio system in whose service area said cellular radio telephone is then present in response to actuation of said call request key by the user.

7. The cellular radio telephone of claim 1, wherein said storing means comprises a read-only memory.

8. A method of providing an indication to a user of a cellular radio telephone usable in a plurality of cellular radio systems, each said cellular radio system having one or more base stations that transmit radio signals throughout a service area over a paging channel and over an access channel, the radio signals including system identification data identifying the cellular radio system from which the radio signals are transmitted, wherein said cellular radio telephone stores system identification data of one of said cellular radio systems thereby establishing the service area throughout which said one cellular radio system transmits as a home service area of said cellular radio telephone, the method comprising the steps of:

establishing a paging channel with a cellular radio system in whose service area said cellular radio telephone is then present in response to initialization of said cellular radio telephone;

detecting system identification data from the radio signals transmitted over said established paging channel by said cellular radio system in whose service area said cellular radio telephone is present at initialization of said cellular radio telephone;

comparing the system identification data detected from the radio signals transmitted over said established paging channel with the stored system identification data;

providing an indication of roamer status of said cellular radio telephone if the system identification data detected from the radio signals transmitted over said established paging channel does not coincide with the stored system identification data;

establishing an access channel between said cellular radio telephone and a cellular radio system in whose service area said cellular radio telephone is then present in response to an input of a call placement request by a user;

detecting system identification data from the radio signals transmitted over said established access channel by said cellular radio system in whose service area said cellular radio telephone is present at the input of the call placement request;

comparing the system identification data detected from the radio signals transmitted over said established access channel with the stored system identification data;

providing said indication of roamer status of said cellular radio telephone if the system identification data detected from the radio signals transmitted over said established access channel does not coincide with the stored system identification data.

9. The method of claim 8, further comprising the step of:

erasing said indication of roamer status if the system identification data subsequently detected from the radio signals transmitted over said established access channel coincides with the stored system identification data.

10. The method of claim 8, further comprising the step of:

providing an indication of home area user status if the system identification data detected from the radio signals transmitted over said established paging channel coincides with the stored system identification data.

11. The method of claim 8, further comprising the step of:

providing an indication of home area user status if the system identification data detected from the radio signals transmitted over said established access channel coincides with the stored system identification data.

12. The method of claim 8, wherein the system identification data of said one cellular radio system is stored in a read-only memory.

13. A radio telecommunication apparatus for use in a plurality of radio telecommunication systems, each having one more base units that broadcast radio signals over a plurality control channels throughout a service area, wherein the radio signals include system identification data identifying the radio telecommunication system from which the radio signals are broadcast, said radio telecommunication apparatus comprising:

storing means for storing system identification data of one of said plurality of radio telecommunication systems;

establishing means for establishing a first control channel with a radio telecommunication system in whose service area said radio telecommunication apparatus is then present in response to initialization of said radio telecommunication apparatus and for establishing a second control channel with a radio telecommunication system in whose service area said radio telecommunication apparatus is then present in response to an input of call placement request by a user;

detecting means coupled to said establishing means for detecting system identification data from the radio signals broadcast over said established first control channel by said radio telecommunication system in whose service area said radio telecommunication apparatus is present at initialization of said radio telecommunication apparatus and for detecting system identification data from the radio signals broadcast over said established second control channel from said radio telecommunication system in whose service area said radio telecommunication apparatus is present at the input of the call placement request;

comparing means, coupled to said detecting means and said storing means, for comparing the system identification data detected from the radio signals broadcast over said established first control channel with the stored system identification data and for comparing the system identification data detected from the radio signals broadcast over said established second control channel with the stored system identification data;

indication means coupled to the comparing means for providing an indication of roamer status if the system identification data detected from the radio signals broadcast over said established first control channel does not coincide with the stored system identification data and for providing the indication of roamer status if the system identification data detected from the radio signal broadcast over said established second control channel does not coincide with the stored system identification data.

14. The radio telecommunication apparatus of claim 13, wherein said indication means eliminates the indication of roamer status if the system identification data subsequently detected from the radio signals broadcast over said established second control channel coincides with the stored system identification data.

15. The radio telecommunication apparatus of claim 13, wherein said indication means provides an indication of home area user status if the system identification data detected from the radio signals broadcast over said established first control channel coincides with the stored system identification data.

16. The radio telecommunication apparatus of claim 13, wherein said indication means provides an indication of home area user status if the system identification data detected from the radio signals broadcast over said established second control channel coincides with the stored system identification data.

17. The radio telecommunication apparatus of claim 13, further comprising a console unit having a call request key, and wherein said establishing means establishes said second control channel with said radio telecommunication system in whose service area said radio telecommunication apparatus is present upon actuation of said call request key by a user.

18. The radio telecommunication apparatus of claim 13, wherein said storing means comprises a read-only memory.

19. A method of providing an indication to a user of a radio telecommunication apparatus used in a plurality of radio telecommunication systems, each said radio telecommunication system having one or more base units that broadcast radio signals over a plurality of control channels throughout a service area, the radio signals including system identification data identifying the radio telecommunication system from which the radio signals are broadcast, wherein said radio telecommunication apparatus stores identification data of one of said radio telecommunication systems thereby establishing the service area throughout which said one radio telecommunication system broadcasts as a home service area of the radio telecommunication apparatus, the method comprising the steps of:

establishing a first control channel between said radio telecommunication apparatus and a radio telecommunication system in whose service area said radio telecommunication apparatus is then present in response to initialization of said radio telecommunication apparatus;

receiving through said established first control channel system identification data from the radio signals broadcast by said radio telecommunication system in whose service area said radio telecommunication apparatus is present at initialization of said radio telecommunication apparatus;

comparing the system identification data received through said established first control channel with the stored system identification data;

providing an indication of roamer status if the system identification data received through said established first control channel does not coincide with the stored system identification data;

establishing a second control channel between said radio telecommunication apparatus and a radio telecommunication system in whose service area said radio telecommunication apparatus is then present in response to an input of a call placement request by the user;

receiving through said established second control channel system identification data from the radio signals broadcast by said radio telecommunication system in whose service area said radio telecommunication apparatus is present at the input of the call placement request;

comparing the system identification data received through said established second control channel with the stored system identification data; and

providing an indication of roamer status if the system identification data received through said established second control channel does not coincide with the stored system identification data.

20. The method of claim 19, further comprising the step of:

erasing said indication of roamer status if the system identification data subsequently received through said established second control channel coincides with the stored system identification data.

21. The method of claim 19, further comprising the step of:

providing an indication of home area user status if the system identification data received through said established first control channel coincides with the stored system identification data.

22. The method of claim 19, further comprising the step of:

providing an indication of home area user status if the system identification data received through said established second control channel coincides with the stored system identification data.

23. The method of claim 19, wherein the system identification data of said one radio telecommunication system is stored in a read-only memory.

24. A cellular radio telephone apparatus for use in a plurality of cellular radio systems, each having one or more base stations that broadcast radio signals throughout a service area, the radio signals including system identification data identifying the cellular radio system from which the radio signals are broadcast, said cellular radio telephone apparatus comprising:

a memory for storing system identification data of one of said cellular radio systems thereby establishing said one cellular radio system as a home cellular system;

a console unit for generating a call request signal upon entry of call request information by a user and including a power switch;

receiving circuitry, responsive to control signals applied thereto, for selectively receiving radio signals broadcast over first and second radio channels by a cellular radio system in whose service area said cellular radio telephone is then present and for detecting the system identification data from said received radio signals;

a control circuit, coupled to said memory, said console unit and said receiving circuitry, for (1) applying control signals to said receiving circuitry when said power switch is switched on, thereby enabling said receiving circuitry to receive the radio signals broadcast over said first radio channel by a cellular radio system in whose service area said cellular radio telephone is then present and to detect the system identification data from said received radio signals, (2) receiving the system identification data detected by said receiving circuitry, (3) generating a roaming status signal if the system identification data does not coincide with the stored system identification data, said roaming status signal indicating that said cellular radio telephone is not within the service area of said home cellular radio system, (4) applying control signals to said receiving circuitry in response to said call request signal thereby enabling said receiving circuitry to receive said radio signals broadcast over said second radio channel and to detect said system identification data from said received radio signals, (5) receiving the system identification data detected by said receiving circuitry, and (6) generating a roaming status signal if the received system identification data does not coincide with the stored system identification data; and

a display, responsive to said roaming status signal, for displaying an indication of roaming status to the user.

25. The cellular radio telephone apparatus of claim 24, wherein:

said control circuit generates a clear display signal if, when said display is displaying an indication of roaming status, said control circuit applies control signals to said receiving circuitry in response to the call request signal and receives system identification data detected by said receiving circuitry that coincides with said stored system identification data; and

said display, in response to said clear display signal, clears the display of the indication of roaming status.