Mobile communication having link ID code checking function

• US 6,597,278 B1
• Filed: 03/30/2000
• Issued: 07/22/2003
• Est. Priority Date: 06/15/1999
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Ando, Toshihide
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): NGUYEN, NAM V
• Application Number:
  US09/538,489
• Time in Patent Office: 1,209 Days
• Field of Search: 340/10.2, 340/10.4, 340/10.41, 340/10.42, 340/572.1, 340/928, 340/825.36, 340/825.37, 340/825.38, 340/825.39, 370/314, 370/326
• US Class Current: 340/5.25
• CPC Class Codes: G07C 5/008 communicating information to a remotely located station transmission systems for measured values G08C
• CPC Class Codes: G08G 1/017 identifying vehicles G08G1/015, G08G1/054 take precedence

Abstract

In a communication system between mobile communication devices and an immobile communication device, a mobile device receives a FCMC signal from the immobile device upon entering a communication service area of the immobile device. The mobile device checks for a coincidence of its own link identification code with other link identification codes included in the FCMC signal and already being used for communication with other mobile devices in the same communication service area. If the coincidence is present, the mobile device changes the own link identification code so that the communication with the immobile device may be executed by using the changed link identification code. In the event that a plurality of mobile devices use the same link identification codes, the immobile device requests the mobile devices to change the same link identification code to different-ones among the mobile devices.

Claims

1. A mobile communication device for communication with an immobile communication device which is fixed to have a communication service area, the mobile device comprising:

communication control means for transmitting its own link identification code upon entering the communication service area of the immobile device, executing a link processing for communication with the immobile device, and executing a communication processing using the link identification code after a link with the immobile device is established;

identification code check means for, prior to executing the link processing, receiving another link identification code which is already being used by the immobile device for communication with another mobile device in the communication service area, and checking a coincidence of the own link identification code with the another identification code; and

identification code change means for changing the own link identification code in response to a check result indicating the coincidence of the link identification code.

2. A mobile communication device of claim 1, wherein:

the identification code check means is further for checking a coincidence of the changed own link identification code; and

the identification code change means is further for changing the changed own link identification code in response to a check result indicating the coincidence of the changed own link identification code.

3. A mobile communication device of claim 1, wherein:

the identification code check means is for repeating its checking operation at least twice.

4. A mobile communication device of claim 1, wherein:

the identification code change means is for changing the own link identification code by adding a predetermined value to the own link identification code.

5. A mobile communication device of claim 1, wherein:

the identification code change means is for changing the own link identification code by using a random number.

6. A mobile communication device of claim 1, wherein:

the communication control means is for causing the identification code change means to change the own link identification code, when a code change command is received from the immobile device during an execution of the link processing.

7. A mobile communication device of claim 1, wherein:

the communication control means is for, when a code change command is received from the immobile device during an execution of the communication processing, interrupting an execution of the communication processing, for causing the identification code change means to change the own link identification code, and for controlling the identification code check means to check a coincidence of the changed link identification code.

8. A mobile communication device of claim 6, wherein:

the identification code change means is for changing the own link identification code based on a random number in a code change operation when the code change command is received.

9. A mobile communication device of claim 7, wherein:

the identification code change means is for changing the own link identification code based on a random number in a code change operation when the code change command is received.

10. A mobile communication device of claim 1, wherein:

the identification code check means is for interrupting its check operation and executing the link processing, when a present communication service area is determined as being inter-related with a previous communication service area in its check operation.

11. A mobile communication device of claim 1 further comprising:

identification code generation means for generating the own link identification code.

12. A mobile communication device of claim 11, wherein:

the identification code generation means is for generating the own link identification code based on a random number.

13. A mobile communication device of claim 11, wherein:

the identification code generation means is for generating a new link identification code before a next check operation is initiated, when the communication processing ends.

14. A mobile communication device of claim 12, wherein:

the identification code generation means is for generating a new link identification code before a next check operation is initiated, when the communication processing ends.

15. An immobile communication device for communication with mobile communication devices, the device comprising:

communication control means for receiving link identification codes transmitted from the mobile devices upon entering a fixed communication service area, executing a link processing for executing communications with the mobile devices, and executing a communication processing by using the link identification codes when links are established; and

link control means for checking for a coincidence among the link identification codes received in the link processing, for invalidating the link identification codes which coincide each other, and for transmitting an identification code change command to the mobile devices which transmitted the coinciding link identification codes.

16. An immobile communication device of claim 15, wherein:

the communication control means is for, when the coincidence is found by the link control means in the communication processing, interrupting the communication processing, invalidating the coinciding link identification codes, and transmitting an identification code change command to the mobile devices transmitted the coinciding identification codes.

17. A communication method between a mobile communication device and an immobile communication device comprising:

transmitting from the mobile device to the immobile device a signal including a link identification code generated at random upon entering a communication service area of the immobile device;

transmitting from the immobile device to the mobile device a signal requesting a change of the transmitted link identification code, when the immobile device determines that the transmitted link identification code coincides with another link identification code which is already being used for a communication with another mobile device within the communication service area; and

changing the link identification code at the mobile device in response to the signal of code change request so that a changed link identification code is transmitted again to the immobile device to establish a link with the immobile device.

18. A communication method of claim 17, further comprising:

checking for, at the immobile device, a coincidence among a plurality of link identification codes newly transmitted from a plurality of mobile devices; and

invalidating the plurality of link coinciding link identification codes and transmitting the signal of code change request to the mobile devices which transmitted the coinciding link identification codes.