Base-station-assisted terminal-to-terminal connection setup

• US 6,574,266 B1
• Filed: 06/25/1999
• Issued: 06/03/2003
• Est. Priority Date: 06/25/1999
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Haartsen, Jacobus Cornelis
• Primary Examiner(s): Liu, Shuwang
• Application Number:
  US09/340,061
• Time in Patent Office: 1,439 Days
• Field of Search: 375/133, 375/134, 375/138, 375/149, 375/219, 375/356, 370/252, 370/349, 370/473, 455/62, 455/434, 455/464
• US Class Current: 375/133
• CPC Class Codes: H04W 48/10 using broadcasted information
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A system and method for establishing ad hoc communication sessions between remote communication terminals is disclosed. A base station transmits a beacon signal including information about the identity and system clock of the base station. Remote terminals within range lock to the base station, synchronizing their system clocks with the base station'"'"'s clock and setting their hop sequence and hop sequence phase based on information in the beacon signal. To establish an ad hoc communication session, a master terminal first establishes a link to the base station, which establishes a link to a desired slave terminal. The base terminal exchanges information between remote terminals that enables the master terminal to establish a direct communication session with a slave terminal.

Claims

1. In a FH communication system, a method for establishing an ad-hoc communication session between first and second remote communication terminals, comprising the steps of:

locking the remote terminals to a base station;

establishing a communication link between the first remote communication terminal and the base station;

transmitting from the first remote communication terminal to the base station information identifying the specific timing and frequency hop sequence of a page scanning process of the first remote communication terminal;

establishing a communication link between the second remote communication terminal and the base station; and

transmitting the identifying information from the base station to the second remote communication terminal, the identifying information being sufficient for beginning and ending the communication session autonomously between the first remote communication terminal and the second remote communication terminal at a future point in time without any further communication from the base station required.

2. The method of claim 1, wherein the step of locking the remote terminals to a base station comprises the step of:

receiving, at the remote terminals, a beacon signal transmitted by the base station over a broadcast channel.

3. The method of claim 2, wherein the step of locking the remote terminals to a base station comprises the step of:

registering the remote terminals with the base station.

4. The method of claim 2, wherein the step of locking the remote terminals to a base station comprises the step of:

synchronizing the clocks of the remote terminals to the clock of the base station.

5. The method of claim 1, wherein the step of transmitting from the first remote communication terminal to the base station comprises the additional step of transmitting from the first remote communication terminal to the base station a request message comprising information identifying the second remote communication terminal.

6. The method of claim 1, wherein the step of establishing a communication link between the base station and the second remote communication terminal comprises the step of:

determining the base station to which the first remote communication terminal is locked.

7. The method of claim 1, comprising the additional step of establishing an ad-hoc connection to the first remote communication terminal by the second remote communication terminal using the identifying information.

8. The method of claim 7, comprising the additional step of establishing an ad-hoc communication session between the first and second remote communication terminals.

9. The method of claim 8, wherein the step of establishing a communication session between the first remote communication terminal and the second remote communication terminal comprises the step of:

synchronizing a hop sequence and hop sequence phase of the second remote communication terminal to a hop sequence and hop sequence phase of the first remote communication terminal.

10. The method of claim 8, wherein the step of establishing a communication session between the first remote communication terminal and the second remote communication terminal comprises the step of:

releasing the communication links between the base station and the remote communication terminals.

11. The method of claim 8, wherein the step of establishing a communication session between the first remote communication terminal and the second remote communication terminal comprises the step of:

maintaining the broadcast link between the base station and the remote communication terminals.

12. The method of claim 8, wherein the step of establishing a communication session between the first remote communication terminal and the second remote communication terminal comprises the step of:

selecting, at the base station, the channel used for the communication link between the first remote communication terminal and the second remote communication terminal.

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

reassigning, at the base station, the channel used for the communication session between the first remote communication terminal and the second remote communication terminal.

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

establishing a communication session between the first remote communication terminal and a third remote communication terminal.

15. A system for establishing an ad-hoc communication session between remote communication terminals, comprising:

a base station adapted to transmit a beacon signal over a broadcast channel, the beacon signal including information identifying the base station and information indicating the base station'"'"'s clock value; and

at least first and second remote communication terminals adapted to receive the beacon signal and to establish a communication link with the base station, wherein the first remote communication terminal is adapted to transmit to the base station information identifying the timing and frequency hop sequence of a page scanning process of the first remote communication terminal, the base station is adapted to provide said identifying information to the second remote communication terminal, the identifying information being sufficient for beginning and ending the communication session autonomously between the first remote communication terminal and the second remote communication terminal at a future point in time without any further communication from the base station required, and the second remote communication terminal is adapted to establish the communication session—

directly with the first remote communication terminal using the identifying information.

16. A system according to claim 15, wherein:

the first remote communication terminal acts as a master terminal in the ad hoc communication session.

17. A system according to claim 15, wherein:

the second remote communication terminal acts as a slave terminal in the ad hoc communication session.

18. A system according to claim 15, wherein:

the first and second remote communication terminals, when linked to the base station, synchronize their clocks with the base station'"'"'s clock.

19. A system according to claim 15, wherein:

the identifying information includes clock information of the first remote communication terminal.

20. A system according to claim 15, wherein:

the first remote communication terminal transmits to the second remote communication terminal the parameters required to define a communication channel with the second remote communication terminal.

21. A system according to claim 20, wherein:

the first remote communication terminal transmits to the second remote communication terminal the parameters required to maintain FH synchronization with the second remote communication terminal.

22. A system according to claim 15, wherein:

the second remote communication terminal synchronizes its clock to the first remote communication terminal'"'"'s clock.