Methods and apparatus for generating, communicating, and/or using information relating to self-noise

• US 20070149126A1
• Filed: 01/17/2006
• Published: 06/28/2007
• Est. Priority Date: 02/24/2003
• Status: Active Grant

• Current Assignee: Arnab Das, John Fan, Junyi Li, Rajiv Laroia, Sunddeep Rangan
• Original Assignee: Qualcomm, Inc.
• Inventors: Das, Arnab, Laroia, Rajiv, Li, Junyi, Fan, John, Rangan, Sunddeep
• Granted Patent: US 8,811,348 B2
• Time in Patent Office: Days
• US Class Current: 455/63.100
• CPC Class Codes: H04B 17/24 with feedback of measurements to the transmitter
• CPC Class Codes: H04B 17/336 Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports

Abstract

A wireless terminal measures the received power of a tone corresponding to an intention base station null output, measures the received power of pilot signals, and determines a signal to noise ratio of the received pilot signal. The wireless terminal calculates a downlink signal to noise ratio saturation level representative of the SNR of a received downlink signal that the wireless terminal would measure on a received signal transmitted by the base station at infinite power. The calculated downlink signal to noise ratio saturation level is a function of the determined interference power, the measured received pilot signal power, and the determined pilot signal SNR. A report is generated corresponding to one of a plurality of quantized levels, the selected quantized level being the closest representation to the calculated downlink signal to noise ratio saturation level. The generated report is communicated using a dedicated control channel segment in a predetermined uplink timing structure.

Claims

1. A method of operating a wireless terminal, the method comprising:

i) determining a downlink signal to noise ratio saturation level; and

ii) transmitting said determined signal to noise ratio saturation level.

2. The method of claim 1, wherein said transmitting includes transmitting said signal to noise ratio saturation level to a base station.

3. The method of claim 2, wherein said transmitting includes transmitting said signal to noise ratio saturation level as a quantized value that is transmitted using OFDM signals.

4. The method of claim 1, wherein said downlink signal to noise ratio saturation level is a downlink signal to noise ratio that said wireless terminal would measure on a received signal that was transmitted by a base station at infinite power.

5. The method of claim 4, wherein said downlink signal to noise ratio saturation level is a function of wireless terminal self-noise.

6. The method of claim 4, wherein said step of determining said signal to noise ratio saturation level is based on measured channel estimation errors.

7. The method of claim 6, wherein said step of determining said signal to noise ratio saturation level is also based on at least one receiver characteristic of a receiver module included in said wireless terminal.

8. The method of claim 7, wherein said at least one receiver characteristic is one of:

receiver filter type, amplifier type, and analog digital converter sampling rate.

9. The method of claim 2, wherein said transmitting step is performed in a predetermined uplink transmission unit dedicated for the transmission of downlink signal to noise ratio saturation level information in a predetermined uplink timing structure.

10. The method of claim 9, further comprising:

repeating steps i) and ii).

11. The method of claim 10, wherein said transmitting step is performed in accordance with the occurrence of transmission units dedicated for the transmission of downlink signal to noise ratio saturation level information on an uplink channel dedicated to said wireless terminal.

12. The method of claim 1, wherein said transmitting step transmits a report in the form of one of a plurality of predetermined report values.

13. The method of claim 12, wherein the predetermined report values are 4 bit values, each value corresponding to a different quantization level.

14. The method of claim 1, further comprising:

prior to performing said transmitting step, making a determination as to whether said downlink signal to noise ratio saturation level is to be transmitted in an uplink transmission unit dedicated to said wireless terminal in which said wireless terminal can select to transmit said downlink signal to noise ratio saturation level or other information.

15. The method of claim 14, wherein determining a downlink signal to noise ratio saturation level includes:

measuring the received power of a tone corresponding to a NULL base station output to thereby determine an interference power N;

measuring the received power of a pilot signal GP₀;

determining the signal to noise ratio of said received pilot signal SNR₀; and

calculating the downlink signal to noise ratio saturation level by the formula;

downlink signal to noise ratio saturation level=(1/SNR₀−

N/(GP₀))<sup>−

1</sup>.

16. A wireless terminal, the wireless terminal comprising:

a downlink signal to noise ratio saturation level determination module; and

a transmission module for transmitting said determined signal to noise ratio saturation level.

17. The wireless terminal of claim 16, wherein said transmission module includes an OFDM transmitter.

18. The wireless terminal of claim 16, wherein said transmission module is coupled to an antenna used to transmit said signal to noise ratio saturation level to a base station.

19. The wireless terminal of claim 16, wherein said downlink signal to noise ratio saturation level is a downlink signal to noise ratio that said wireless terminal would measure on a received signal that was transmitted by a base station at infinite power.

20. The wireless terminal of claim 19, wherein said signal to noise ratio saturation level is a function of wireless terminal self-noise.

21. The wireless terminal of claim 19, wherein said determination module includes a channel estimation measurement module for measuring channel estimation errors used in determining said signal to noise ratio saturation level.

22. The wireless terminal of claim 21, further comprising:

memory including stored receiver characteristic information used by said determination module to determine said signal to noise ratio saturation level.

23. The wireless terminal of claim 22, wherein said stored receiver characteristic information includes at least one of:

receiver filter type, amplifier type, and analog digital converter sampling rate information.

24. The wireless terminal of claim of claim 18, further comprising:

memory including uplink timing structure information; and

a transmission control module for controlling, as a function of said uplink timing structure information when said transmission module transmits said determined signal to noise ratio saturation level.

25. The wireless terminal of claim 24, wherein said transmission control module controls the transmission of downlink signal to noise ratio saturation level information in accordance with the occurrence of transmission units dedicated for the transmission of downlink to noise ratio saturation level information on a uplink channel dedicated to said wireless terminal as indicated by said uplink timing structure information.

26. The wireless terminal of claim 16, wherein said downlink signal to noise ratio saturation level is transmitted in the form of one of a plurality of predetermined report values.

27. The wireless terminal of claim 26, wherein the predetermined report values are 4 bit values, each value corresponding to a different downlink signal to noise ratio saturation level quantization level.