Reliability detection of channel quality indicator (CQI) and application to outer loop power control

• US 8,428,522 B2
• Filed: 06/15/2012
• Issued: 04/23/2013
• Est. Priority Date: 12/04/2002
• Status: Active Grant

• Current Assignee: Pantech Wireless, LLC (Ideahub, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Dick, Stephen G., Miller, James M., Rudolf, Marian
• Primary Examiner(s): Dao, Minh D
• Application Number:
  US13/524,348
• Publication Number:
  US 20120250525A1
• Time in Patent Office: 312 Days
• Field of Search: 455/69, 455/562.1, 455/561, 370/335, 370/342, 370/328, 370/329
• US Class Current: 455/69
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0033 arrangements specific to the transmitter
• CPC Class Codes: H04L 1/1671 the supervisory signal being transmitted together with control information
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04L 2001/125 Arrangements for preventing errors in the return channel
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04W 28/24 Negotiating SLA [Service Level Agreement]; Negotiating QoS [Quality of Service]
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 52/0225 using monitoring of external events, e.g. the presence of a signal
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 52/20 using error rate
• CPC Class Codes: H04W 52/262 taking into account adaptive modulation and coding [AMC] scheme AMC per se H04L1/0001
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method for performing outer loop power control in wireless communications is disclosed. A channel quality indicator (CQI) message is transmitted by a wireless transmit/receive unit (WTRU). The WTRU receives a power control command, the power control command being derived by: decoding the CQI message; computing a decision metric value for each symbol in the CQI message; determining whether the CQI message is erroneous; and counting a number of erroneous CQI messages, wherein the power control command is based on whether the number of erroneous CQI messages exceeds a threshold. An uplink transmission power of the WTRU is adjusted based on the power control command.

Claims

1. A method for performing outer loop power control in wireless communications, comprising:

transmitting a channel quality indicator (CQI) message by a wireless transmit/receive unit (WTRU);

receiving a power control command, the power control command being derived by;

decoding the CQI message;

computing a decision metric value for each symbol in the CQI message;

determining whether the CQI message is erroneous; and

counting a number of erroneous CQI messages, wherein the power control command is based on whether the number of erroneous CQI messages exceeds a threshold; and

adjusting an uplink transmission power of the WTRU based on the power control command.

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 second threshold, wherein the CQI message is erroneous on a condition that the comparison result is below the second 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 power control command is generated after expiration of the time interval.

8. A wireless transmit/receive unit (WTRU) configured to perform outer loop power control, comprising:

a transmitter configured to transmit a channel quality indicator (CQI) message;

a receiver configured to receive a power control command, the power control command being derived by;

decoding the CQI message;

computing a decision metric value for each symbol in the CQI message;

determining whether the CQI message is erroneous; and

counting a number of erroneous CQI messages, wherein the power control command is based on whether the number of erroneous CQI messages exceeds a threshold; and

a transmission power adjusting device configured to adjust an uplink transmission power of the WTRU based on the power control command.

9. The WTRU of claim 8, 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 second threshold, wherein the CQI message is erroneous on a condition that the comparison result is below the second threshold.

10. The WTRU according to claim 9, 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.

11. The WTRU according to claim 9, wherein the comparing includes calculating a ratio of the largest decision metric value to the second largest decision metric value.

12. The WTRU according to claim 8, wherein the counting includes using at least one counter.

13. The WTRU according to claim 8, 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.

14. The WTRU according to claim 8, wherein:

the counting is performed over a time interval; and

the power control command is generated after expiration of the time interval.