System and method for forward link power balancing in a wireless communication system

• US 6,351,650 B1
• Filed: 01/28/1999
• Issued: 02/26/2002
• Est. Priority Date: 01/28/1999
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Lundby, Stein A., Razoumov, Leonid, Holtzman, Jack
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): SOBUTKA, PHILIP
• Application Number:
  US09/239,187
• Time in Patent Office: 1,125 Days
• Field of Search: 455/522, 455/442, 455/436, 455/422, 455/446, 455/67.1, 455/68, 455/69, 455/70, 455/92, 455/127, 455/561, 370/331.2
• US Class Current: 455/522
• CPC Class Codes: H04W 52/221 using past power control commands
• CPC Class Codes: H04W 52/226 using past references to control power, e.g. look-up-table
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff

Abstract

Forward power control during a soft handoff in a wireless communication system is accomplished by tracking each power command (PC) transmitted from a mobile unit to two or more base station transceiver systems (BTSs). Each BTS may interpret power commands differently due to noise. However, the power commands are relayed to a selector along with additional data transmitted in a conventional fashion. The selector determines the power levels of each BTS and transmits power charge commands to maintain power balance between the BTSs. The BTSs may transmit each PC command to the selector or accumulate several PC commands and send a PC history to the selector. The selector generates a reference PC history, which may be one of the PC histories transmitted from a BTS, a combination thereof, the result of data processing on the one or more PC histories. Individual power change commands or the reference PC history is transmitted back to the BTS to adjust the transmitter output level of each BTS so that the BTSs are transmitting at compatible signal levels.

Claims

1. A system for power control during soft handoff of a wireless communication device, the system comprising:

a first base station transceiver communicating with the wireless communication device and receiving data therefrom, the received data comprising a set of power control commands detected by the first base station transceiver as a first detected power command set;

a first power control history storage area to store data indicative of the first detected power control command set;

a second base station transceiver communicating with the wireless communication device and receiving data therefrom, the received data comprising the set of power control commands detected by the second base station transceiver as a second detected power command set;

a second power control history storage area to store data indicative of the second detected power control command set; and

a selector to control the soft handoff from the first base station transceiver to the second base station transceiver, the selector receiving the data from the first and second power control history storage areas and calculating a power control level based on the data from at least one of the first and second power control history storage areas, the selector transmitting a power control signal, based on the calculated power control level, to the second base station transceiver to set a power level of the second base station transceiver.

2. The system of claim 1 wherein the first and second detected power command sets each comprise a plurality of detected power control commands.

3. The system of claim 1 wherein the selector adjusts the power control signal based on the data in both the first and second power control history storage areas.

4. The system of claim 1 wherein the selector transmits the power control signal as a plurality of power control commands to incrementally alter the power level of the second base station transceiver.

5. The system of claim 1 wherein the first and second power control history storage areas are associated with the second base station transceivers, respectively.

6. The system of claim 1, further including a base station controller wherein the selector is associated with the base station controller and the first and second power control history storage areas are associated with the base station controller.

7. A system for power control of a wireless communication device, the system comprising:

a first base station transceiver having a first controllable transmit power level and communicating with the wireless communication device and receiving data therefrom, the received data comprising at least one power control command detected by the first base station transceiver as at least one first detected power command;

a first power control (PC) history storage area for storing the at least one first detected power command;

a second base station transceiver having a second controllable transmit power level and communicating with the wireless communication device and receiving data therefrom, the received data comprising at least one power control command detected by the second base station transceiver as at least one second detected power command;

a second power control history storage area for storing the at least one second detected power command; and

a selector to receive power command data indicative of the at least one first and second power control commands from the first and second power control history storage areas, and to generate power correction data based on the received power command data, the selector transmitting the power correction data to at least one of the first and second base station transceivers to control the controllable transmit power level thereof.

8. The system of claim 7 wherein the first and second base station transceivers detect a plurality of first and second detected power control commands, respectively, the received power command data being indicative of the plurality of first and second detected power control commands.

9. The system of claim 8 wherein the first and second base station transceivers periodically send the data in the first and second power control history storage areas to the selector.

10. The system of claim 9 wherein the selector generates the power correction data based on the plurality of first detected power control commands in the first PC history storage area and transmits the power correction data to the second base station transceiver to control the controllable power level thereof.

11. The system of claim 9 wherein the selector generates the power correction data based on a difference between the plurality of first detected power control commands in the first PC history storage area and the plurality of second detected power control commands in the second PC history storage area, the selector further transmitting first and second power correction data to the first and second base station transceivers, respectively, to control the controllable power level thereof.

12. The system of claim 7 wherein the selector generates first and second power correction data for the first and second base station transceivers, respectively, based on the received power command data and transmits the first and second power correction data to the first and second base station transceivers, respectively.

13. The system of claim 7 wherein the selector generates the power correction data to maintain the first and second controllable power levels at identical levels.

14. The system of claim 7 wherein the selector generates the power correction data to maintain the first controllable power level at a level different from the second controllable power level.

15. The system of claim 7 wherein the selector transmits the power correction data to the second base station transceiver.

16. The system of claim 15 wherein the second base station transceiver generates an internal power control command to set a power level of the second base station transceiver based on the power correction data.

17. The system of claim 7 wherein the power correction data comprises power correction commands and the second base station transceiver sets a power level of the second base station transceiver based on the power correction commands.

18. The system of claim 7 wherein the selector calculates a power control level based on the power correction data, the selector transmitting a plurality of power control commands to the first and second base station transceivers to incrementally alter a power level of the first and second base station transceivers, respectively.

19. A method for power control in a wireless communication system, the method comprising:

receiving data from a wireless communication device by a first base station transceiver, the received data comprising power control commands detected by the first base station transceiver as first detected power commands;

storing the first detected power commands in a first power control history storage area;

receiving data from a wireless communication device by a second base station transceiver, the received data comprising power control commands detected by the second base station transceiver as second detected power commands;

storing the second detected power commands in a second power control history storage area; and

generating power correction data by a selector, based on the contents of at least one of the history storage areas, indicative of the first and second power control commands.

20. The method of claim 19, further comprising generating a reference power control data based on one of the data indicative of the first and second power control commands and transmitting the reference power control data to at least one of the first and second base station transceivers.

21. The method of claim 20, further comprising generating an internal power control command within each of the first and second base station transceivers to set a power level of the first and second base station transceivers, respectively, based on the reference power control data.

22. The method of claim 19 wherein the received data in the first and second base station transceivers comprises a plurality of first and second detected power commands and transmitting data to the selector comprises transmitting data indicative of the first and second pluralities of power control commands to the selector.

23. The method of claim 22, further comprising storing the plurality of first and second detected power control commands in first and second power control (PC) history storage areas associated with the first and second base station transceivers, respectively, and periodically sending the data in the first and second power control history storage areas to the selector.

24. The method of claim 23 wherein generating the power correction data is based on the plurality of first detected power control commands in the first PC history storage area, the method further comprising transmitting the power correction data to the second base station transceiver to control the controllable power level thereof.

25. The method of claim 23 wherein generating the power correction data is based on a difference between the plurality of first detected power control commands in the first PC history storage area and the plurality of second detected power control commands in the second PC history storage area, the method further comprising transmitting first and second power correction data to the first and second base station transceivers, respectively, to control the controllable power level thereof.

26. The method of claim 19, further comprising transmitting the power correction data to the second base station transceiver to set a power level of the second base station transceiver.

27. The method of claim 19, further comprising transmitting a plurality of power control commands, based on the power correction data, to the second base station transceiver to incrementally alter a power level of the second base station transceiver.

28. The method of claim 19, further comprising:

transmitting the power correction data to the second base station transceiver; and

generating an internal power control command to set a power level of the second base station transceiver based on the power correction data.

29. The method of claim 19, further comprising transmitting power control signals, based on the power correction data, to the first and second base station to set a power level of the first and second base station transceivers, respectively.

30. The method of claim 19, further comprising sending the power correction data to the first base station transceiver to set the power level of the first base station transceiver at a level identical to the power level of the second base station transceiver.

31. The method of claim 19, further comprising sending the power correction data to the first base station transceiver to set the power level of the first base station transceiver at a level different from the power level of the second base station transceiver.