Method and system for terminal communication

• US 6,650,629 B1
• Filed: 01/07/2000
• Issued: 11/18/2003
• Est. Priority Date: 01/07/1999
• Status: Expired due to Term

• Current Assignee: FIPA Frohwitter Intellectual Property AG
• Original Assignee: Hitachi, Ltd.
• Inventors: Ishida, Kazuhito, Takahashi, Yousuke
• Primary Examiner(s): Ngo, Ricky
• Assistant Examiner(s): Swickhamer, Christopher M
• Application Number:
  US09/479,785
• Time in Patent Office: 1,411 Days
• Field of Search: 370/310.2, 370/313, 370/320, 370/328, 370/331, 370/335, 370/342, 370/441, 370/447, 370/479, 370/485, 370/504, 455/422, 455/517, 375/130, 375/140, 375/141, 375/146, 375/147
• US Class Current: 370/335
• CPC Class Codes: H04W 84/20 Master-slave selection or change arrangements

Abstract

In the CDMA environment, a local call is directly made between two mobile stations (MS) without the involvement of a base station. The local direct calls do not interfere with any existing communication lines, and the implementation on the CDMA based units includes Master MS units and Slave MS units which selects one of currently unused offset values in a pilot signal for a local direct call in the CDMA environment.

Claims

1. A method of providing an optional direct communication between terminal communication units according to code division multiple access which is also used for communication between the terminal communication units via a base station in a communication network, comprising the acts of:

a) searching currently used identification information for said code division multiple access identifying the base station surrounding a first terminal communication unit, said identification information being assigned from a set of predetermined unique identifiers, the base station having a base service area;

b) selecting an unused one of said predetermined unique identifiers as a temporary unique identifier for direct communication between the first terminal communication unit and a second terminal communication unit; and

c) establishing said direct communication between said first terminal communication unit and said second terminal communication unit according to said code division multiple access using said temporary unique identifier regardless of a relative position of said first terminal communication unit and said second terminal communication unit with respect to the base service area.

2. The method of providing an option to communicate directly between terminal communication units according to claim 1 wherein said first terminal communication unit and said second terminal communication unit are within a predetermined distance with each other.

3. The method of providing an option to communicate directly between terminal communication units according to claim 1 wherein said identification information includes any combination of an offset value for a pilot signal, a frequency value of a pilot signal and pilot channel data in a pilot signal.

4. The method of providing an option to communicate directly between terminal communication units according to claim 3 wherein said step c) further comprising:

transmitting said pilot signal with a second offset value from said first terminal communication unit, said base station transmitting said pilot signal with a first offset value;

determining at said second terminal communication unit whether or not said pilot signal is sent from said first terminal communication unit based upon said second offset value and whether or not said second terminal communication unit is being called; and

transmitting a reply signal from said second terminal communication unit to said first terminal communication unit.

5. The method of providing an option to communicate directly between terminal communication units according to claim 1 wherein a first base has a first service area where said first terminal communication unit is located in said first service area, said step a) determining said currently used identification information within said first service area of said first base for said code division multiple access surrounding said first terminal communication unit.

6. The method of providing an option to communicate directly between terminal communication units according to claim 1 wherein said currently used identification information identifies said direct communication between said terminal communication units.

7. The method of providing an option to communicate directly between terminal communication units according to claim 1 wherein said currently used identification information identifies said communication between said terminal communication units via said base station.

8. The method of providing an option to communicate directly between terminal communication units according to claim 3 wherein said step c) further comprising:

broadcasting said pilot signal with a second offset value from said first terminal communication unit, said base station transmitting said pilot signal with a first offset value;

registering said second terminal communication unit at said first terminal communication unit; and

periodically monitoring at said second terminal communication unit said pilot signal with said second offset from said first terminal communication unit.

9. The method of providing an option to communicate directly between terminal communication units according to claim 8 wherein after establishing said direct communication between said first terminal communication unit and said second terminal communication unit, said first terminal communication unit transmits a pilot signal indicating that said direct communication in progress.

10. The method of providing an option to communicate directly between terminal communication units according to claim 1 wherein said step b) further comprising:

determining whether or not said selected unused one of said predetermined unique identifiers has a predetermined amount of distance from a used one of said of predetermined unique identifiers; and

based upon said distance determination, said step c) establishes said direct communication.

11. The method of providing an option to communicate directly between terminal communication units according to claim 1 wherein said direct communication between said first terminal communication unit and said second terminal communication unit is established when communication between said first terminal communication unit and said second terminal communication unit is not available via the base station.

12. The method of providing an option to communicate directly between terminal communication units according to claim 1 wherein the communication between said first terminal communication unit and said second terminal communication unit is established via the base station when said direct communication between said first terminal communication unit and said second terminal communication unit is not available.

13. A system for providing an optional direct communication between terminal communication units according to code division multiple access which is also used for communication between the terminal communication units via a base station in a communication network, comprising:

a first terminal communication unit which searches currently used identification information for said code division multiple access identifying the base station surrounding said first terminal communication unit, said identification information being assigned from a set of predetermined unique identifiers, said first terminal communication unit selecting an unused one of said predetermined unique identifiers as a temporary unique identifier, the base station having a base service area; and

a second terminal communication unit which is capable of communicating with said first terminal communication unit via the base station, said first terminal communication unit and said second terminal communication unit establishing said direct communication between said first terminal communication unit and said second terminal communication unit according to said code division multiple access using said temporary unique identifier regardless of a relative position of said first terminal communication unit and said second terminal communication unit with respect to the base service area.

14. The system for providing an option to communicate directly between terminal communication units according to claim 13 wherein said first terminal communication unit and said second terminal communication unit are within a predetermined distance with each other.

15. The system for providing an option to communicate directly between terminal communication units according to claim 13 wherein said identification information includes any combination of an offset value for a pilot signal, a frequency value of a pilot signal and pilot channel data in a pilot signal.

16. The system for providing an option to communicate directly between terminal communication units according to claim 13 wherein a first base has a first service area where said first terminal communication unit is located, said first terminal communication unit determining said currently used identification information within said first service area of said first base for said code division multiple access surrounding said first terminal communication unit.

17. The system for providing an option to communicate directly between terminal communication units according to claim 13 wherein said currently used identification information identifies said direct communication between said terminal communication units.

18. The system for providing an option to communicate directly between terminal communication units according to claim 13 wherein said currently used identification information identifies said communication between said terminal communication units via said base station.

19. The system for providing an option to communicate directly between terminal communication units according to claim 13 wherein said first terminal communication unit determines whether or not said selected unused one of said predetermined unique identifiers has a predetermined amount of distance from a used one of said of predetermined unique identifiers, based upon said distance determination, said first terminal communication unit establishing said direct communication.

20. The system for providing an option to communicate directly between terminal communication units according to claim 13 herein said direct communication between said first terminal communication unit and said second terminal communication unit is established when communication between said first terminal communication unit and said second terminal communication unit is not available via the base station.

21. The system for providing an option to communicate directly between terminal communication units according to claim 13 wherein the communication between said first terminal communication unit and said second terminal communication unit is established via the base station when said direct communication between said first terminal communication unit and said second terminal communication unit is not available.

22. A wireless terminal communication device which communicates with a second terminal communication device via a base station as well as which directly communicates with the second terminal communication device without the base station, comprising:

a receiver which receives a transmission signal from the base station and the second terminal communication device;

a searching circuit being connected to said receiver and searching for used identification information identifying the base station based upon CDMA surrounding said wireless terminal communication device, said used identification information being assigned from a set of predetermined identifiers, the base station having a base service area;

a selector circuit being connected to said searching circuit and selecting an unused one of said predetermined identifiers;

a transmitter being connected to said selector and transmitting said unused identification information; and

a line establishing circuit connected to said receiver and said transmitter for establishing a communication line with the second terminal communication device according to said CDMA after said unused identification information is transmitted regardless of a relative position of said wireless terminal communication device and the second terminal communication device with respect to the base service area.

23. The wireless terminal communication device according to claim 22 wherein said receiver further includes a forward link receiver which receives a forward link signal from the base station and a reverse link receiver which receives a reverse link signal from the second terminal communication device, said transmitter further including a forward link transmitter which transmits a forward link signal to the second terminal communication device and a reverse link transmitter which transmits a reverse link signal to the base station.

24. The wireless terminal communication device according to claim 22 wherein said used identification information and said unused identification information are respectively a diffusion code with a unique offset value used for pilot channel diffusion.

25. The wireless terminal communication device according to claim 24 further comprising an information generation circuit which is connected to said transmitter and generates an information signal indicative of specifying the second terminal communication device in initiating a call with the second terminal communication device, said transmitter transmitting said information signal via a channel other than a pilot channel.

26. The wireless terminal communication device according to claim 24 further comprising a hand off circuit which is connected to said line establishing circuit and hands off the second terminal communication device to the first terminal communication device, upon a successful handing off of the second terminal communication device, said line establishing circuit establishing the communication line.

27. The wireless terminal communication device according to claim 26 further comprising an information generation circuit which is connected to said transmitter and generates an information signal indicative of specifying the second terminal communication device in initiating a call with the second terminal communication device, said transmitter transmitting the information signal via a paging channel.

28. The wireless terminal communication device according to claim 22 herein said line establishing circuit directly establishes the communication line with the second terminal communication device when the communication line with the second terminal communication device is not available via the base station.

29. The wireless terminal communication device according to claim 22 wherein said line establishing circuit establishes the communication line with the second terminal communication device via the base station when the communication line with the second terminal communication device is not available.