Feedback of channel quality information

• US 7,656,843 B2
• Filed: 06/12/2007
• Issued: 02/02/2010
• Est. Priority Date: 02/21/2002
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Wei, Yongbin, Lundby, Stein A., Puig-Oses, David
• Primary Examiner(s): Sheikh; Ayaz R
• Assistant Examiner(s): HALIYUR, VENKATESH N
• Application Number:
  US11/762,042
• Publication Number:
  US 20070287487A1
• Time in Patent Office: 966 Days
• Field of Search: 370204-463, 455/69, 455/562.1, 455/13.4, 455/522, 455/574, 455/561, 455/102, 455/272
• US Class Current: 370/334
• CPC Class Codes: H04L 1/001 applied to control information
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

Methods and apparatus are presented for improving the feedback of channel information to a serving base station, which allows a reduction in the reverse link load while allowing the base station to improve the forward link data throughput. Over a channel quality indicator channel, a carrier-to-interference (C/I) symbol is transmitted over multiple slots at a reduced rate, which increases the likelihood that the base station can decode said symbol. The reduced rate mode can be selectively triggered by a high velocity condition or other unfavorable channel condition. The C/I symbol is used to determine transmission formats, power levels, and data rates of forward link transmissions.

Claims

1. A base station for controlling the operation of a quality feedback channel in a wireless communication system, comprising:

a scheduler for interpreting a channel quality value associated with a transmission channel

and for determining a condition of the transmission channel; and

a base station transmission subsystem for transmitting a message to a remote station transmission subsystem to transmit the channel quality value having a fixed quantity of bits over one slot of the channel quality feedback channel if the transmission channel condition is favorable, and

to transmit the channel quality value having the fixed quantity of bits over a plurality of slots of the channel quality feedback channel if the channel condition is not favorable.

2. The base station of claim 1, wherein the condition of the transmission channel is based upon a velocity estimate.

3. The base station of claim 1, wherein the condition of the transmission channel is based upon a power level estimate.

4. The base station of claim 1, wherein the condition of the transmission channel is based upon whether a fast fade occurs in the transmission channel.

5. A remote station for improving the reception of a channel quality value, comprising:

a receiving subsystem for determining whether the condition of a transmission channel is favorable; and

a transmission subsystem for transmitting the channel quality value having a fixed quantity of bits over one slot of a feedback channel if the condition of the transmission channel is favorable, and

for transmitting the channel quality value having the fixed quantity of bits over more than one slot of the feedback channel if the condition of the transmission channel is unfavorable.

6. The remote station of claim 5, wherein

the transmission subsystem repeats the channel quality value over a frame of the feedback channel if the channel quality value is transmitted over more than one slot.

7. The remote station of claim 5, wherein the channel condition is unfavorable if the remote station and a station travel at a high velocity in relation to each other, wherein the remote station originates the feedback channel and the station originates the transmission channel.

8. A method for improving the reception of a channel quality value at a base station, comprising:

determining whether the condition of a feedback channel from a remote station is favorable;

if the condition of the channel is unfavorable, then transmitting a control signal to the remote station, wherein the control signal triggers a reduced rate mode for transmitting the channel quality value having a fixed quantity of bits over a feedback channel from the remote station; and

if the condition of the channel is favorable, then allowing the remote station to control the transmission of the channel quality value having the fixed quantity of bits over the feedback channel.

9. An apparatus for improving the reception of a channel quality value at a base station, comprising:

means for determining whether the condition of a feedback channel from a remote station is favorable;

means for transmitting a control signal to the remote station if the condition of the channel is unfavorable, wherein the control signal triggers a reduced rate mode for transmitting the channel quality value having a fixed quantity of bits over a feedback channel from the remote station; and

if the condition of the channel is favorable, then allowing the remote station to control the transmission of the channel quality value having the fixed quantity of bits over the feedback channel.