Setting baseband gain for signals below noise

1. A method in a first wireless device (WD) for setting a receiver baseband gain for receiving wanted signals with negative signal to noise by a receiver of the WD, the method comprising:

for each channel of the WD, determining a setting of a receive baseband gain of the receiver that produces an IQ magnitude parameter having a predetermined value, the predetermined value being predetermined as a value that results from an applied receive baseband gain setting that produces a predetermined receiver sensitivity; and

for each channel of the WD, storing the determined receive baseband gain setting for subsequent application to signals received by the receiver.

2. The method of claim 1 , wherein the IQ magnitude parameter is a sum of squares of outputs of I and Q analog-to-digital converters (ADCs).

3. The method of claim 1 , wherein the predetermined value is determined as an IQ magnitude parameter value having a least variance.

4. The method of claim 3 , wherein the least variance value of the IQ magnitude parameter is calculated by:

reading an IQ magnitude value i times, and taking an average, A of the readings;

recording averages, A j , for J sets of readings of the IQ magnitude, {A 1 , A 2 , A 3 , . . . A J };

determining a median value, M k , of the averages, MEDIAN{A 1 , A 2 , A 3 , . . . A J };

recording the median values, Mt, for K sets of determinations of the median values, {M 1 , M 2 , M 3 , . . . M K };

determining a minimum median value, MIN {M 1 , M 2 , M 3 , . . . M K }; and

returning the minimum median value as the IQ magnitude parameter value having the least variance.

5. The method of claim 1 , wherein the predetermined value is determined based at least in part on determining a response to a plurality of test packets in a preoperational setting.

6. The method of claim 1 , wherein the receive baseband gain settings are determined when an antenna of the WD is receiving only noise.

7. The method of claim 1 , wherein a determined receive baseband gain setting corresponds to direct sequence spread spectrum signal receiver sensitivity.

8. The method of claim 1 , wherein a second determined receive baseband gain setting corresponds to orthogonal frequency division multiple (OFDM) receiver sensitivity.

9. A first wireless device (WD), comprising:

a wireless transmitter configured to transmit a ranging signal and a wireless receiver configured to receive a response signal from a second WD in response to the ranging signal; and

processing circuitry in communication with the wireless receiver and with the wireless transmitter, the processing circuitry configured to, for each channel of the first WD:

vary settings of a receive baseband gain of the wireless receiver and determine an IQ parameter value for each receive baseband gain setting; and

record a receive baseband gain setting that produces a predetermined IQ parameter value for the channel, the predetermined IQ parameter value being predetermined based on a determined sensitivity of the wireless receiver resulting from each of a plurality of receive baseband gain settings.

10. The WD of claim 9 , wherein the determined IQ parameter value is a sum of squares of outputs of I and Q analog-to-digital converters (ADCs).

11. The WD of claim 9 , wherein the predetermined IQ parameter value is determined as an IQ magnitude parameter value having a least variance.

12. The WD of claim 9 , wherein the predetermined IQ parameter value is determined based at least in part on a response to a plurality of test packets in a preoperational setting.

13. The WD of claim 9 , wherein the receive baseband gain settings are determined when an antenna of the WD is receiving only noise.

14. The WD of claim 9 , wherein the determined IQ parameter is based at least in part on an average value of IQ parameter values determined over time.