Reliability detection of channel quality indicator (CQI) and application to outer loop power control
A method for determining a channel quality in wireless communications includes receiving a high speed shared control channel (HS-SICH) transmission. An expected number of HS-SICH transmissions and a number of unsuccessful HS-SICH transmissions are counted. The number of unsuccessful HS-SICH transmissions includes a number of failed HS-SICH transmissions and a number of missed HS-SICH transmissions. The expected number of HS-SICH transmissions and the number of unsuccessful HS-SICH transmissions over a fixed time period are periodically reported, whereby the reporting is an indication of the channel quality.
1. A method for performing outer loop power control in wireless communications, including:
receiving a channel quality indicator (CQI) message;
decoding the CQI message;
computing a decision metric value for each symbol in the CQI message;
determining whether the CQI message is erroneous;
counting a number of erroneous CQI messages; and
signaling a wireless/transmit receive unit to adjust an uplink transmission power on a condition that the number of erroneous CQI messages exceeds a threshold.
2. The method according to claim 1 , wherein the determining includes:
selecting a largest decision metric value;
selecting a second largest decision metric value;
comparing the largest decision metric value and the second largest decision metric value against a threshold, wherein the CQI message is erroneous on a condition that the comparison result is below the threshold.
3. The method according to claim 2 , wherein the decision metric values are logarithmic and the comparing includes determining a difference between the largest decision metric value and the second largest decision metric value.
4. The method according to claim 2 , wherein the comparing includes calculating a ratio of the largest decision metric value to the second largest decision metric value.
5. The method according to claim 1 , wherein the counting includes using at least one counter.
6. The method according to claim 1 , wherein the counting includes counting a total number of high-speed shared control channels (HS-SICHs) received, a number of false HS-SICHs received, and a number of HS-SICHs that have been missed.
7. The method according to claim 1 , wherein:
the counting is performed over a time interval; and
the signaling is performed after expiration of the time interval.
8. The method according to claim 1 , wherein the method is performed by a radio network controller and the CQI message is received from a wireless transmit/receive unit.
9. The method according to claim 1 , wherein the method is performed by a base station and the CQI message is received from a wireless transmit/receive unit.
10. A base station configured to perform outer loop power control, including:
a receiver configured to receive a channel quality indicator (CQI) message;
a decoder configured to decode the CQI message;
a processor configured to:
compute a decision metric value for each symbol in the CQI message; and
determine whether the CQI message is erroneous;
a counter configured to count a number of erroneous CQI messages; and
a transmitter configured to signal a wireless/transmit receive unit to adjust an uplink transmission power on a condition that the number of erroneous CQI messages exceeds a threshold.
11. The base station according to claim 10 , wherein the processor is further configured to:
select a largest decision metric value;
select a second largest decision metric value;
compare the largest decision metric value and the second largest decision metric value against a threshold, wherein the CQI message is determined to be erroneous on a condition that the comparison result is below the threshold.
12. The base station according to claim 11 , wherein the decision metric values are logarithmic and the processor is configured to determine a difference between the largest decision metric value and the second largest decision metric value.
13. The base station according to claim 11 , wherein the processor is configured to calculate a ratio of the largest decision metric value to the second largest decision metric value.
14. The base station according to claim 10 , wherein the counter is configured to count a total number of high-speed shared control channels (HS-SICHs) received, a number of false HS-SICHs received, and a number of HS-SICHs that have been missed.
15. The base station according to claim 10 , wherein:
the counter is configured to count the number of erroneous CQI messages over a time interval; and
the transmitter is configured to signal the wireless transmit/receive unit after expiration of the time interval.
16. A radio network controller configured to perform outer loop power control, comprising:
a receiver configured to receive a channel quality indicator (CQI) message;
a decoder configured to decode the CQI message;
a processor configured to:
compute a decision metric value for each symbol in the CQI message; and
determine whether the CQI message is erroneous;
a counter configured to count a number of erroneous CQI messages; and
a transmitter configured to signal a wireless/transmit receive unit to adjust an uplink transmission power on a condition that the number of erroneous CQI messages exceeds a threshold.
17. The radio network controller according to claim 16 , wherein the processor is further configured to:
select a largest decision metric value;
select a second largest decision metric value;
compare the largest decision metric value and the second largest decision metric value against a threshold, wherein the CQI message is determined to be erroneous on a condition that the comparison result is below the threshold.
18. The radio network controller according to claim 17 , wherein the decision metric values are logarithmic and the processor is configured to determine a difference between the largest decision metric value and the second largest decision metric value.
19. The radio network controller according to claim 17 , wherein the processor is configured to calculate a ratio of the largest decision metric value to the second largest decision metric value.
20. The radio network controller according to claim 16 , wherein the counter is configured to count a total number of high-speed shared control channels (HS-SICHs) received, a number of false HS-SICHs received, and a number of HS-SICHs that have been missed.
21. The radio network controller according to claim 16 , wherein:
the counter is configured to count the number of erroneous CQI messages over a time interval; and
the transmitter is configured to signal the wireless transmit/receive unit after expiration of the time interval.