Operation of a forward link acknowledgement channel for the reverse link data

• US 7,600,170 B2
• Filed: 02/04/2004
• Issued: 10/06/2009
• Est. Priority Date: 01/10/2003
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Chen, Tao, Gaal, Peter
• Primary Examiner(s): Chase; Shelly A
• Application Number:
  US10/772,670
• Publication Number:
  US 20040158790A1
• Time in Patent Office: 2,071 Days
• Field of Search: 714748-749
• US Class Current: 714/748
• CPC Class Codes: H04B 17/24 with feedback of measurements to the transmitter
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04J 13/0048 Walsh
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0034 where the transmitter decides based on inferences, e.g. use of implicit signalling
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0073 Special arrangements for feedback channel
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/1671 the supervisory signal being transmitted together with control information
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 1/1825 Adaptation of specific ARQ protocol parameters according to transmission conditions
• CPC Class Codes: H04L 1/1845 Combining techniques, e.g. code combining
• CPC Class Codes: H04L 1/1854 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 1/1858 Transmission or retransmission of more than one copy of acknowledgement message
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 2001/125 Arrangements for preventing errors in the return channel
• CPC Class Codes: H04W 52/48 during retransmission after error or non-acknowledgment

Abstract

An acknowledgement method in a wireless communication system. Initially, a reverse supplemental channel (R-SCH) frame is received at a base station. The base station then transmits an acknowledgement (ACK) signal if quality of the received R-SCH frame is indicated as being good. A negative acknowledgement (NAK) signal is transmitted only if the received data frame is indicated as being bad but has enough energy such that, if combined with energy from retransmission of the data frame, it would be sufficient to permit correct decoding of the data frame. If the best base station is known, the acknowledgement method may reverse the transmission of the acknowledgement signals for the best base station so that only NAK signal is sent. A positive acknowledgement is assumed in the absence of an acknowledgement. This is done to minimize the transmit power requirements.

Claims

1. A method of encoding acknowledgement channels in base stations of a wireless communication system, the method comprising:

receiving a reverse link traffic channel data frame from a remote terminal;

allowing absence of acknowledgement (ACK) signals on an acknowledgement channel of a best base station to indicate that quality of the received data frame is good;

allowing absence of negative acknowledgement (NAK) signals on acknowledgement channels of secondary base stations to indicate that quality of the received data frame is bad;

encoding the ACK signals and the NAK signals, and transmitting the encoded signals on the acknowledgement channels during a switching period.

2. The method of claim 1, wherein the switching period is configured as a duration of a soft-handoff.

3. The method of claim 1, wherein the best base station is selected based on forward link channel quality.

4. The method of claim 3, wherein the forward link channel quality includes a strongest forward link pilot signal detected by a remote terminal.

5. The method of claim 1, wherein the best base station is selected based on reverse link power control information.

6. The method of claim 5, wherein the reverse link power control information includes power control (PC) commands.

7. The method of claim 6, further comprising:

enabling the remote terminal to determine that a base station is the best base station if a difference between ‘

power down’ and

‘

power up’

PC commands exceeds a first threshold.

8. The method of claim 7, further comprising:

enabling a base station to determine that it is the best base station if the difference between ‘

power down’ and

‘

power up’

PC commands exceeds a second threshold.

9. The method of claim 8, wherein the second threshold is larger than the first threshold.

10. The method of claim 9, further comprising:

enabling a base station to determine that it is the secondary base station if the difference between ‘

power down’ and

‘

power up’

PC commands is below a third threshold.

11. The method of claim 10, wherein the third threshold is smaller than the first threshold.

12. The method of claim 10, further comprising:

transmitting both ACK and NAK signals explicitly if the difference between ‘

power down’ and

‘

power up’

PC commands is above the third threshold but is below the second threshold.

13. An apparatus for wireless communication comprising:

means for receiving a reverse link traffic channel data frame from a remote terminal;

means for allowing absence of acknowledgement (ACK) signals on an acknowledgement channel of a best base station to indicate that quality of the received data frame is good;

means for allowing absence of negative acknowledgement (NAK) signals on acknowledgement channels of secondary base stations to indicate that quality of the received data frame is bad;

means for encoding the ACK signals and the NAK signals, and transmitting the encoded signals on the acknowledgement channels during a switching period.

14. The apparatus of claim 13, wherein the switching period is configured as a duration of a soft-handoff.

15. The apparatus of claim 13, wherein the best base station is selected based on forward link channel quality.

16. The apparatus of claim 15, wherein the forward link channel quality includes a strongest forward link pilot signal detected by a remote terminal.

17. The apparatus of claim 13, wherein the best base station is selected based on reverse link power control information.

18. The apparatus of claim 17, wherein the reverse link power control information includes power control (PC) commands.

19. The apparatus of claim 18, further comprising:

means for enabling the remote terminal to determine that a base station is the best base station if a difference between ‘

power down’ and

‘

power up’

PC commands exceeds a first threshold.

20. The apparatus of claim 19, further comprising:

means for enabling a base station to determine that it is the best base station if the difference between ‘

power down’ and

‘

power up’

PC commands exceeds a second threshold.

21. The apparatus of claim 20, wherein the second threshold is larger than the first threshold.

22. The apparatus of claim 21, further comprising:

means for enabling a base station to determine that it is the secondary base station if the difference between ‘

power down’ and

‘

power up’

PC commands is below a third threshold.

23. The method of claim 22, wherein the third threshold is smaller than the first threshold.

24. The method of claim 23, further comprising:

transmitting both ACK and NAK signals explicitly if the difference between ‘

power down’ and

‘

power up’

PC commands is above the third threshold but is below the second threshold.

25. A computer-readable storage device containing instructions for executing the following steps:

receiving a reverse link traffic channel data frame from a remote terminal;

allowing absence of acknowledgement (ACK) signals on an acknowledgement channel of a best base station to indicate that quality of the received data frame is good;

allowing absence of negative acknowledgement (NAK) signals on acknowledgement channels of secondary base stations to indicate that quality of the received data frame is bad;

encoding the ACK signals and the NAK signals, and transmitting the encoded signals on the acknowledgement channels during a switching period.

26. The computer-readable storage device of claim 25, wherein the switching period is configured as a duration of a soft-handoff.

27. The computer-readable storage device of claim 25, wherein the best base station is selected based on forward link channel quality.

28. The computer-readable storage device of claim 27, wherein the forward link channel quality includes a strongest forward link pilot signal detected by a remote terminal.

29. The computer-readable storage device of claim 25, wherein the best base station is selected based on reverse link power control information.

30. The computer-readable storage device of claim 29, wherein the reverse link power control information includes power control (PC) commands.

31. The computer-readable storage device of claim 30, further comprising instructions for executing the following steps:

enabling the remote terminal to determine that a base station is the best base station if a difference between ‘

power down’ and

‘

power up’

PC commands exceeds a first threshold.

32. The computer-readable storage device of claim 31, further comprising instructions for executing the following steps:

enabling a base station to determine that it is the best base station if the difference between ‘

power down’ and

‘

power up’

PC commands exceeds a second threshold.

33. The computer-readable storage device of claim 32, wherein the second threshold is larger than the first threshold.

34. The computer-readable storage device of claim 33, further comprising instructions for executing the following steps:

enabling a base station to determine that it is the secondary base station if the difference between ‘

power down’ and

‘

power up’

PC commands is below a third threshold.

35. The computer-readable storage device of claim 34, wherein the third threshold is smaller than the first threshold.

36. A base station of a wireless communication system, the method comprising:

an RF front end configured to receive a reverse link traffic channel data frame from a remote terminal; and

a controller configured to;

allow absence of acknowledgement (ACK) signals on an acknowledgement channel to indicate that quality of the received data frame is good when the base station operates as a best base station;

allow absence of negative acknowledgement (NAK) signals on acknowledgement channels to indicate that quality of the received data frame is bad when the base station operates as a secondary base station; and

encode the ACK signals and the NAK signals; and

a transmitter configured to transmit the encoded signals on the acknowledgement channels during a switching period.