Method and apparatus for establishing direct communication for mobiles in a radio communication system

• US 20040121766A1
• Filed: 10/29/2003
• Published: 06/24/2004
• Est. Priority Date: 12/23/2002
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola Mobility, Inc. (Lenovo Group Ltd.)
• Inventors: Benson, Maya, Kotzin, Michael D.
• Granted Patent: US 7,684,813 B2
• Time in Patent Office: Days
• US Class Current: 455/425
• CPC Class Codes: H04W 76/14 Direct-mode setup
• CPC Class Codes: H04W 92/18 between terminal devices

Abstract

A radiotelephone method includes detecting other mobile stations and identifying possible relay candidates among the other mobile stations. The method then includes communicating information about the candidates to a base station. Communication with a second mobile station is requested of the base station at a first mobile station. If the first mobile station and the second mobile station are physically close, the base station instructs the first mobile station and the second mobile station to establish direct communication.

Claims

1. A method for operating a radiotelephone system, the method comprising:

at a first mobile station, requesting communication with a second mobile station; and

at a base station serving the first mobile station, if radio propagation conditions between the first mobile station and the second mobile station are sufficiently good, instructing the first mobile station and the second mobile station to establish direct communication.

2. The method of claim 1 wherein requesting communication comprises:

communication information about the radio propagations conditions between the first mobile station and the second mobile station to the base station.

3. The method of claim 1 wherein instructing the first mobile station and the second mobile station to establish direct communication comprises:

establishing independent radio links with the first mobile station and the second mobile station;

transmitting a direct communication instruction to the first mobile station and the second mobile station; and

terminating the independent radio links.

4. The method of claim 1 further comprising:

at the first mobile station, determining the radio propagation conditions between the first mobile station and the second mobile station;

communicating information about the radio propagation conditions to the base station; and

updating the information about the radio propagation conditions.

7. The method of claim 4 further comprising:

determining if each of the first mobile station and the second mobile station is a detected mobile of the other mobile station.

5. A method for operating a radiotelephone system, the method comprising:

at one or more mobile stations of the radiotelephone system, detecting other mobile stations to which radio propagation conditions are sufficiently good;

at the one or more mobile stations, communicating information about the detected mobile stations to a base station of the radiotelephone system;

at a first mobile station, requesting communication with a second mobile station; and

at the base station, if the radio propagation conditions between the first mobile station and the second mobile station are sufficiently good, instructing the first mobile station and the second mobile station to establish direct communication.

6. The method of claim 5 further comprising:

at the base station, receiving the communication request from the first mobile station; and

from the information about the detected mobiles from the first mobile station and the second mobile station, determining if the first mobile station and the second mobile station may initiate direct communication.

8. The method of claim 6 further comprising:

at the base station, determining a location of the first mobile station;

determining a location of the second mobile station; and

determining information about relative proximity of the first mobile station and the second mobile station based on the location of the first mobile station and the location of the second mobile station.

9. The method of claim 5 wherein instructing the first mobile station and the second mobile station to establish direct communication comprises:

initiating a first communication link between the base station and the first mobile station;

communicating a direct communication instruction to the first mobile station;

initiating a second communication link between the base station and the second mobile station;

communicating a direct communication instruction to the second mobile station;

terminating the first communication link and the second communication link.

10. The method of claim 5 wherein detecting other mobile stations comprises:

detecting respective uplink transmissions from respective mobile stations to base stations of the radiotelephone system.

11. The method of claim 10 further comprising:

determining a received signal strength for a detected uplink transmission from a detected mobile station;

if the received signal strength exceeds a threshold, identifying the detected mobile station as a possible relay candidate.

12. The method of claim 5 further comprising:

at the first mobile station, in response to the instruction establish direct communication, entering a packet-based connectionless communication mode with the second mobile station.

13. The method of claim 12 wherein packet-based connectionless communication mode comprises entering an Opportunity Driven Multiple Access relay mode.

14. A method for operating a base station in a radiotelephone system, the method comprising:

receiving a request from a first mobile station to initiate a call with a second mobile station in the radiotelephone system;

based at least in part on a relay candidate list associated with the first mobile station, determining if the second mobile station is physically close to the first mobile station; and

if so, instructing the first mobile station and the second mobile station to enter a relay mode for direct link communication.

15. The method of claim 14 wherein instructing the first mobile station and the second mobile station to enter a relay mode comprises:

communicating information about the relay mode a over a first link with the first mobile station;

communicating information about the relay mode a over a second link with the second mobile station; and

terminating both the first link and the second link.

16. The method of claim 14 further comprising:

receiving from respective mobile stations of the radiotelephone system information about relay candidates of the respective mobile stations;

storing the information in respective relay candidate lists; and

receiving updates from the respective mobile stations for updating the respective relay candidate lists.

17. A radiotelephone comprising:

a radio communication circuit configured for two-way radio communication with remote radio devices; and

a controller configured to control the radio communication circuit to establish a radio link to a remote base station to convey a request for communication with another radiotelephone and to receive over the radio link a direct communication instruction, and further configured to control the radio communication circuit to interrupt the radio link and establish a relay radio link with the other radiotelephone in response to the direct communication instruction.

18. The radiotelephone of claim 17 further comprising:

a memory configured to store a relay candidate list, the controller being further configured to control the radio communication circuit to establish a radio link to the remote base station to convey the relay candidate list to the remote base station.

19. The radiotelephone of claim 18 wherein the controller is further configured to control the radio communication circuit to detect radio transmissions from other radiotelephones and, in response to the detected uplink transmissions, to populate the relay candidate list.