Method and apparatus for providing wireless communication system synchronization

• US 20030174666A1
• Filed: 03/07/2003
• Published: 09/18/2003
• Est. Priority Date: 12/04/1998
• Status: Active Grant

• Current Assignee: Charles E. Wheatley III, Edward G. Tiedemann Jr, Mark S. Wallace, Steven J. Howard, Walton J. Rod
• Original Assignee: Charles E. Wheatley III, Edward G. Tiedemann Jr, Mark S. Wallace, Steven J. Howard, Walton J. Rod
• Inventors: Tiedemann, Edward G. Jr., Wheatley, Charles E. III, Howard, Steven J., Wallace, Mark S., Walton, J. Rod
• Granted Patent: US 7,391,759 B2
• Time in Patent Office: Days
• US Class Current: 370/324
• CPC Class Codes: H04B 7/2696 Over the air autonomous synchronisation, e.g. by monitoring network activity H04B7/2693 takes precedence

Abstract

When insufficient traffic is present in the network to maintain synchronization in this manner, other methods must be used. One approach involves making direct measurements of the timing between base stations. This is accomplished in one of two ways. The base may interrupt its transmissions on all sectors for a short interval during which it determines the time of arrival of signals from other base stations. Given knowledge of the other base station locations, time errors relative to all other base stations may be derived. Alternatively, the base may send a short signal at high power in the mobile transmit band. This time-of-arrival of this signal is measured by the surrounding base stations and the time errors between pairs of base stations are computed. In some cases, a base station may be isolated sufficiently from all other base stations in the network such that direct base-to-base measurement is not viable. In this case, a fixed mobile is placed at a location in the handoff region between the isolated cell and another cell in the network. The fixed mobile either performs measurements of base station pilots on command of the base and reports the timing information, or sends a burst transmission at a specified time and power level to be measured by the base stations.

Claims

1. A method of providing synchronization in a wireless communication system, comprising:

transmitting a first wireless communication signal to a first subset of a plurality of mobile stations on a forward link frequency band; and

transmitting a second wireless communication signal to a second subset of said plurality of mobile stations on said forward link frequency band;

inhibiting transmission of said second wireless communication signal for a monitoring period;

receiving said first wireless communication signal during said monitoring period; and

adjusting a clock in accordance with said received first wireless communication signal.

2. A system of providing synchronization in a wireless communication system, comprising:

means for transmitting a first wireless communication signal to a first subset of a plurality of mobile stations on a forward link frequency band; and

means for transmitting a second wireless communication signal to a second subset of said plurality of mobile stations on said forward link frequency band;

means for inhibiting transmission of said second wireless communication signal for a monitoring period;

means for receiving said first wireless communication signal during said monitoring period; and

means for adjusting a clock in accordance with said received first wireless communication signal.

3. A method of providing synchronization in a wireless communication system,

comprising:

receiving a first signal from a base station on a forward link frequency band;

adjusting said internal clock in accordance with said received forward link signal;

transmitting a second signal on said forward link frequency band; and

inhibiting transmission of said second signal on said forward link frequency band while receiving said first signal from said base station.

4. A system of providing synchronization in a wireless communication system, comprising:

means for receiving a first signal from a base station on a forward link frequency band;

means for adjusting said internal clock in accordance with said received forward link signal;

means for transmitting a second signal on said forward link frequency band; and

means for inhibiting transmission of said second signal on said forward link frequency band while receiving said first signal from said base station.

5. A method of providing synchronization in a wireless communication system,

comprising:

receiving signals from a subset of said plurality of mobile stations on a reverse link frequency band;

transmitting a reverse link wireless communication signal on a reverse link frequency band during a synchronization interval; and

receiving said reverse link wireless communication signal; and

adjusting an internal clock in accordance with said received wireless communication signal; and

inhibiting the reception of said reverse while transmitting on said reverse link frequency band.

6. The method of claim 5 wherein said transmitting said reverse link wireless communication signal is transmitted at a predetermined time and wherein said second base station adjusts said internal clock based on the time of arrival of said wireless communication signal.

7. A system of providing synchronization in a wireless communication system, comprising:

means for receiving signals from a subset of said plurality of mobile stations on a reverse link frequency band;

means for transmitting a reverse link wireless communication signal on a reverse link frequency band during a synchronization interval; and

means for receiving said reverse link wireless communication signal; and

means for adjusting an internal clock in accordance with said received wireless communication signal; and

means for inhibiting the reception of said reverse while transmitting on said reverse link frequency band.

8. A method of providing synchronization in a wireless communication system, comprising:

transmitting signals on a forward link frequency band;

receiving a signal from a mobile station on a reverse link frequency band;

transmitting a synchronization probe on said reverse link frequency band; and

inhibiting the reception of said signal from said mobile station while said reverse link transmitter is transmitting on said reverse link frequency band.

9. A system of providing synchronization in a wireless communication system, comprising:

means for transmitting signals on a forward link frequency band;

means for receiving a signal from a mobile station on a reverse link frequency band;

means for transmitting a synchronization probe on said reverse link frequency band; and

means for inhibiting the reception of said signal from said mobile station while said reverse link transmitter is transmitting on said reverse link frequency band.

10. A method of providing synchronization in a wireless communication system, comprising:

transmitting a first wireless communication signal on a forward link frequency band;

transmitting a second wireless communication signal on said forward link frequency band; and

receiving said first wireless communication signal and said second wireless communication signal and generating a signal indicative of timing indicated in said first wireless communication signal and said second wireless communication signal.

11. A system of providing synchronization in a wireless communication system, comprising:

means for transmitting a first wireless communication signal on a forward link frequency band;

means for transmitting a second wireless communication signal on said forward link frequency band; and

means for receiving said first wireless communication signal and said second wireless communication signal and generating a signal indicative of timing indicated in said first wireless communication signal and said second wireless communication signal.

12. A system for synchronizing the clocks of a first base station and a second base station comprising:

dummy station having a fixed location for transmitting a wireless communication signal;

first base station for receiving said wireless communication signal and for computing the time of arrival of said wireless communication signal at said first base station and for sending a message indicative of the time of arrival of said wireless communication signal at said first base station to a central controller;

second base station for receiving said wireless communication signal and for computing the time of arrival of said wireless communication signal at said second base station and for sending a message indicative of the time of arrival of said wireless communication signal at said second base station to a central controller; and

central controller for generating a timing adjustment message in accordance with said message indicative of the time of arrival of said wireless communication signal and said message indicative of the time of arrival of said wireless communication signal at said second base station and for transmitting said timing adjustment message to said first base station.

13. A method of providing synchronization in a wireless communication system, comprising:

transmitting a wireless communication signal;

receiving said wireless communication signal at a first base station, computing the time of arrival of said wireless communication signal at said first base station, and sending a message indicative of the time of arrival of said wireless communication at said first base station;

receiving said wireless communication signal at a second base station, computing the time of arrival of said wireless communication signal at said second base station, and sending a message indicative of the time of arrival of said wireless communication signal at said second base station; and

generating a timing adjustment message in accordance with said message indicative of the time of arrival of said wireless communication signal at said first base station and said message indicative of the time of arrival of said wireless communication signal at said second base station and for transmitting said timing adjustment message to said first base station.

14. A system of providing synchronization in a wireless communication system, comprising:

means for transmitting a wireless communication signal;

means for receiving said wireless communication signal at a first base station, computing the time of arrival of said wireless communication signal at said first base station, and sending a message indicative of the time of arrival of said wireless communication at said first base station;

means for receiving said wireless communication signal at a second base station, computing the time of arrival of said wireless communication signal at said second base station, and sending a message indicative of the time of arrival of said wireless communication signal at said second base station; and

means for generating a timing adjustment message in accordance with said message indicative of the time of arrival of said wireless communication signal at said first base station and said message indicative of the time of arrival of said wireless communication signal at said second base station and for transmitting said timing adjustment message to said first base station.