Methods for the synchronization of multiple base stations in a wireless communication system

• US 20070140209A1
• Filed: 02/02/2007
• Published: 06/21/2007
• Est. Priority Date: 10/30/1998
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Lee, Robert, Hebsgaard, Anders, Quigley, Thomas, Dworkin, David, Denney, Lisa
• Granted Patent: US 7,899,034 B2
• Time in Patent Office: Days
• US Class Current: 370/345
• CPC Class Codes: H04B 1/1036 with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters H04B1/123 takes precedence; filter circuits H03H
• CPC Class Codes: H04J 3/0664 unidirectional timestamps
• CPC Class Codes: H04J 3/067 Details of the timestamp structure
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 2025/03808 Transmission of equaliser coefficients
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end

Abstract

A plurality of base station devices are linked together and synchronized to facilitate communication between the respective base station devices and respective downlink subscriber stations. According to one embodiment of the invention, one of the base station devices is designated as a master device, and the other base station devices are designated as slave devices. The respective base station devices are connected to each other by means of a synchronization bus. The master base station device then generates and broadcasts a future time stamp value, which is received by the respective slave base station devices. When the time stamp counter in the master base station device reaches the transmitted value, a control signal is broadcast over the synchronization bus. The slave base station devices then retrieve the time stamp value and reset their respective local time stamp counters to the received value. In this manner, the base station devices are synchronized.

Claims

1. In a wireless system, a method comprising:

storing time stamp information at a first base station having a first counter;

setting the first counter of the first base station based on a signal provided by a second base station having a second counter; and

generating timing information for transmission by the first base station using the first counter.

2. The method of claim 1, wherein setting the first counter includes synchronizing the first counter with the second counter based on the signal.

3. The method of claim 1, wherein storing the time stamp information includes storing the time stamp information associated with a future time stamp.

4. The method of claim 1, wherein setting the first counter is performed in response to detecting a time stamp value at the second counter that corresponds to the time stamp information.

5. The method of claim 1, further comprising:

setting a third counter of a third base station based on the signal provided by the second base station.

6. The method of claim 5, further comprising:

connecting the second base station and the first and third base stations via a synchronization bus.

7. The method of claim 1, further comprising:

updating the time stamp information in response to a lapse of a predetermined amount of time.

8. In a wireless system, a method comprising:

transmitting MAP information including identifiers associated with respective uplink channels from a first base station to subscriber stations coupled to the uplink channels; and

filtering the MAP information at a second base station based on an identifier of the MAP information that corresponds with an uplink channel that is connected to the second base station.

9. The method of claim 8, further comprising:

storing a portion of the MAP information that corresponds with the uplink channel that is coupled to the second base station at the second base station.

10. The method of claim 8, further comprising:

disregarding a portion of the MAP information that does not correspond with the uplink channel that is coupled to the second base station at the second base station.

11. The method of claim 8, further comprising:

transmitting the MAP information from the first base station to the second base station, wherein filtering the MAP information at the second base station is performed in response to transmitting the MAP information from the first base station to the second base station.

12. A method of synchronizing plural base stations in a wireless system, the method comprising:

generating a future time stamp value;

transmitting the future time stamp value to a first base station and to a plurality of second base stations;

storing the future time stamp value at each base station;

comparing the future time stamp value with a current time stamp value at the first base station;

generating a signal at the first base station when the future time stamp value matches the current time stamp value;

transmitting the signal to the respective second base stations; and

at each second base station, setting a local counter to the future time stamp value upon receipt of the signal.

13. The method of claim 12, wherein transmitting the command signal to the respective second base stations includes broadcasting the command signal via a bus.

14. The method of claim 12, wherein transmitting the future time stamp value includes transmitting the value a predetermined number of cycles prior to reaching the future time stamp value.

15. The method of claim 12, wherein transmitting the future time stamp value includes transmitting the value between approximately eight and approximately 64 cycles prior to reaching the future time stamp value.

16. The method of claim 12, wherein generating the future time stamp value is performed once per predetermined period.

17. The method of claim 12, wherein generating the future time stamp value is performed once per millisecond.

18. The method of claim 12, further comprising:

storing a time stamp value to a register using a first clock domain; and

reading the time stamp value from the register using a second clock domain.

19. In a wireless system having multiple base stations, with each base station being coupled to at least one uplink channel, a method of allocating time slots on a plurality of uplink channels, the method comprising:

assigning a unique identifier to each of the uplink channels;

generating time-slot allocation information for the respective uplink channels;

transmitting the allocation information to at least one of the base stations;

forwarding the allocation information to a plurality of subscriber stations via a downlink channel;

transmitting the allocation information to the remainder of the base stations;

at each base station, determining whether the allocation information pertains to an uplink channel associated with that base station; and

at each base station, processing the allocation information if the allocation information pertains to an uplink channel associated with that base station.

20. The method of claim 19, wherein the generated time-slot information includes time slot allocations, channel identification information, and subscriber station identification information.

21. The method of claim 19, wherein determining whether the allocation information pertains to that base station includes processing the allocation information to compare channel identification information with the one or more channels coupled to that base station.

22. The method of claim 19, wherein processing includes processing the allocation information if channel identification information in the allocation information matches with an identifier of a channel connected to that base station.

23. The method of claim 19, wherein transmitting the allocation information to less than all of the base stations includes transmitting the allocation information to a master base station.

24. The method of claim 23, wherein transmitting the allocation information to the remainder of the base stations includes broadcasting the allocation information from the master base station to the other base stations via a bus.