Wednesday, April 24, 2013

Some MSR SORA facts


http://www.v3best.com/sdr/UploadFiles/2011121203749702.jpg
             Source of figure : http://www.v3best.com/sdr/UploadFiles/2011121203749702.jpg 

1. The default date rate is 11Mbps in 802.11b standard which leads the highest throughput but also the shortest distance. If you change the data rate to lower one, for example, 1Mbps using the "dot11config.exe" tool. The communication range should be extended.

2. When the distance is large, you may need to increase the gain.

3. RF board matters. With two different RF boards say WARP , USRP DB the range covered are different for the same amount of power.

4. Baseband algorithm also matters for the coverage.

5. Improving the antenna should improve the distance in theory because SNR will be improved.


6. The format of the dump file is simple. It is basically an array of signal block. A signal block is of 128Bytes, with 16B header and 28 samples. Each sample is COMPLEX16.

7. Sampling rate is 44MHz of current Sora .

8. Channel switching time : It may take some time for RF to stabilize after issue the switch command.
a. User-mode: kernel context switching cost + register write cost + RF board response time < 100 us in most time
b. kernel-mode: register write cost + RF board reponse time < 10 us in most time

9. There is no event  framework  in Sora.

10. The TX signal file of Sora is a array of 8-bit I and 8-bit Q, however, the I/Q width of  DAC chip in USRP is 14bit.

This information has been taken from http://research.microsoft.com/en-us/projects/sora/



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