Method and system for controlling transmission power of a downlink signaling channel based on enhanced uplink transmission failure statistics

• US 20050255873A1
• Filed: 04/27/2005
• Published: 11/17/2005
• Est. Priority Date: 04/30/2004
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Dick, Stephen G., Terry, Stephen E., Zhang, Guodong
• Granted Patent: US 7,599,707 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04L 1/1867 Arrangements specially adapted for the transmitter end
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel
• CPC Class Codes: H04W 52/20 using error rate
• CPC Class Codes: H04W 52/225 Calculation of statistics, e.g. average, variance
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels

Abstract

A method and system for controlling the transmission power of at least one downlink (DL) enhanced uplink (EU) signaling channel such that enhanced dedicated channel (E-DCH) DL signaling is delivered efficiently and reliably. The system includes at least one wireless transmit/receive unit (WTRU), at least one Node-B and a radio network controller (RNC). At least one of the WTRU and the Node-B compute EU transmission failure statistics on the DL EU signaling channel and report the EU transmission failure statistics to the RNC. The RNC then adjusts a transmission power offset of the DL EU signaling channel to be used in determining transmission power level of the DL EU signaling channel at the Node-B based on the EU transmission failure statistics.

Claims

1. In a wireless communication system including at least one wireless transmit/receive unit (WTRU), at least one Node-B and a radio network controller (RNC), where an enhanced uplink (EU) operation is supported so that the Node-B sends EU control information to the WTRU via a downlink (DL) EU signaling channel for EU operation, a method for controlling transmission power of the DL EU signaling channel, the method comprising:

(a) at least one of the WTRU and the Node-B computing EU transmission failure statistics and reporting the computed statistics to the RNC; and

(b) based on the EU transmission failure statistics, the RNC adjusting transmission power offset of the DL EU signaling channel to be used in determining transmission power level of the DL EU signaling channel at the Node-B.

2. The method of claim 1 wherein the RNC adjusts a transmission power offset for at least one of an acknowledge (ACK) message or a non-acknowledge (NACK) message included in a signal sent by the Node-B to the WTRU via the DL EU signaling channel in response to the Node-B receiving EU dedicated channel (E-DCH) transmissions from the WTRU.

3. The method of claim 2 wherein the EU transmission failure statistics are determined by subtracting the number of EU media access control (MAC-e) failures of the WTRU detected by the WTRU from the number of MAC-e failures of the WTRU detected by the Node-B.

4. The method of claim 3 wherein the MAC-e failures of the WTRU occur when the number of retransmissions exceeds a predetermined retransmission limit.

5. The method of claim 3 wherein the MAC-e failures of the WTRU occur when a EU transmission data expires before successfully transmitted.

6. The method of claim 2 wherein the EU transmission failure statistics are determined by subtracting the number of MAC-e failures of the WTRU detected by the WTRU from the number of radio link control (RLC) recovery requests for the WTRU.

7. The method of claim 2 wherein transmission power for the NACK message is set higher than transmission power for the ACK message.

8. The method of claim 1 wherein the Node-B adjusts transmission power for EU channel allocation information transmitted in response to receiving a channel allocation request from the WTRU.

9. The method of claim 8 wherein the EU transmission failure statistics are determined as the number of times that the Node-B receives no E-DCH transmissions from the WTRU within a predetermined time period after the EU channel allocation information is transmitted.

10. The method of claim 8 wherein the EU transmission failure statistics are determined based on the number of times that the Node-B receives EU transmissions which are not consistent to the EU channel allocation information.

11. The method of claim 8 wherein the EU transmission failure statistics are determined based on the number of times that the WTRU fails to receive channel allocation information from the Node-B in response to the channel allocation request within a specified time period.

12. The method of claim 1 wherein transmission power level of the DL EU signaling channel for a specific WTRU is determined with reference to transmission power for a DL dedicated physical control channel (DPCCH) for the specific WTRU.

13. A wireless communication system for controlling transmission power of a downlink (DL) enhanced uplink (EU) signaling channel, the system comprising:

(a) a radio network controller (RNC);

(b) at least one wireless transmit/receive unit (WTRU) for computing and reporting EU transmission failure statistics and reporting the statistics to the RNC;

(c) at least one Node-B for computing EU transmission failure statistics and reporting the statistics to the RNC; and

(d) at least one DL EU signaling channel in communication with the WTRU and the Node-B, wherein the Node-B sends signals to the WTRU via the DL UE signaling channel, and the RNC adjusts a transmission power offset of the DL EU signaling channel to be used in determining transmission power level of the signals sent by the Node-B based on the EU transmission failure statistics reported in steps (b) and (c).

14. The system of claim 13 wherein the RNC adjusts a transmission power offset for at least one of an acknowledge (ACK) message or a non-acknowledge (NACK) message included in a signal sent by the Node-B to the WTRU via the DL EU signaling channel in response to the Node-B receiving EU dedicated channel (E-DCH) transmissions from the WTRU.

15. The system of claim 14 wherein the EU transmission failure statistics are determined by subtracting the number of EU media access control (MAC-e) failures of the WTRU detected by the WTRU from the number of MAC-e failures of the WTRU detected by the Node-B.

16. The system of claim 15 wherein the MAC-e failures of the WTRU occur when the number of retransmissions exceeds a predetermined retransmission limit.

17. The system of claim 15 wherein the MAC-e failures of the WTRU occur when EU transmission data expires before being successfully transmitted.

18. The system of claim 14 wherein the EU transmission failure statistics are determined by subtracting the number of MAC-e failures of the WTRU detected by the WTRU from the number of radio link control (RLC) recovery requests for the WTRU.

19. The system of claim 14 wherein transmission power for the NACK message is set higher than transmission power of the ACK message.

20. The system of claim 13 wherein the RNC adjusts a transmission power offset of EU channel allocation information signaled by the Node-B in response to a channel allocation request by the WTRU.

21. The system of claim 20 wherein the EU transmission failure statistics are determined based on the number of times that the Node-B fails to receive EU transmissions from the WTRU after the EU channel allocation information is transmitted.

22. The system of claim 20 wherein the EU transmission failure statistics are determined based on the number of times that the Node-B receives an EU transmission which is not consistent to the EU channel allocation information.

23. The system of claim 20 wherein the EU transmission failure statistics are determined as the number of times that the WTRU fails to receive channel allocation information from the Node-B within a specified time period.

24. The system of claim 13 wherein transmission power of the DL EU signaling channel for a specific WTRU is determined with reference to transmission power for a DL dedicated physical control channel (DPCCH) for the specific WTRU.

25. A wireless communication system for controlling transmission power of a downlink (DL) enhanced uplink (EU) signaling channel, the system comprising:

(a) a radio network controller (RNC);

(b) at least one wireless transmit/receive unit (WTRU) for computing EU transmission failure statistics and reporting the statistics to the RNC;

(c) at least one Node-B; and

(d) at least one DL EU signaling channel in communication with the WTRU and the Node-B, wherein the Node-B sends signals to the WTRU via the DL UE signaling channel, and the RNC adjusts a transmission power offset of the DL EU signaling channel to be used in determining transmission power level of the signals sent by the Node-B based on the EU transmission failure statistics reported to the RNC by the WTRU.

26. A wireless communication system for controlling transmission power of a downlink (DL) enhanced uplink (EU) signaling channel, the system comprising:

(a) a radio network controller (RNC);

(b) at least one wireless transmit/receive unit (WTRU);

(c) at least one Node-B for computing EU transmission failure statistics and reporting the statistics to the RNC; and

(d) at least one DL EU signaling channel in communication with the WTRU and the Node-B, wherein the Node-B sends signals to the WTRU via the DL UE signaling channel, and the RNC adjusts a transmission power offset of the DL EU signaling channel to be used in determining transmission power level of the signals sent by the Node-B based on the EU transmission failure statistics reported to the RNC by the Node-B.

27. A wireless communication system comprising:

(a) a wireless transmit/receive unit (WTRU); and

(b) a downlink (DL) enhanced uplink (EU) signaling channel dedicated to communicate with the WTRU, wherein the power level of the DL EU signaling channel is based on the power level of a current DL dedicated control channel.

28. The system of claim 27 wherein the power level of the DL EU signaling channel is based on the current DL dedicated control channel power level and an initial power offset.

29. The system of claim 28 further comprising:

(c) a Node-B; and

(d) a radio network controller (RNC), wherein the RNC adjusts the power offset based on EU transmission failure statistics computed and reported to the RNC by at least one of the WTRU and the Node-B.

30. A wireless communication system comprising:

(a) a plurality of wireless transmit/receive units (WTRUs);

(b) a radio network controller (RNC); and

(c) a downlink (DL) enhanced uplink (EU) signaling channel shared by the WTRUs, wherein the power level of the DL EU signaling channel is based on a common DL signaling power level initially set by the RNC.

31. The system of claim 30 wherein the power level of the DL EU signaling channel is based on the common DL signaling power level initially set by the RNC and a power offset.

32. The system of claim 31 wherein the system further comprises a Node-B, and the RNC adjusts the power offset based on EU transmission failure statistics computed and reported to the RNC by at least one of the plurality of WTRUs and the Node-B.