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Some questions about MSR Software Radio

    Question

  • I am a participant of Microsoft SORA project. I am very honored to participate in this project. RecentlyI have met several issues when testing the WIFI transceiver. Now I share the issues and expect someone to give the answers.

    A: The communication distance becomes short in the custom transmission mode. Are there any programs could increase the communication distance.

    B: Whether the above problem can be achieved by improving the antenna or not?

    C: How to distribute clock iin the 4*4 MIMO antenna experiments.

    Thursday, June 24, 2010 8:23 AM

Answers

  • Dear Iamtoytoy,

    Very glad to hear you have successfully set up the Sora system!

    Answers for your questions:

    A: Communication distance

    (1) Did you try to change the data rate? 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) Did you try to change the gain on RX path? Since we didn't implement any automatic gain control in the sample code, it requires you to tune the gain manually. When the distance is large, you may need to increase the gain. There are two options: i) dot11config --rxpa /*value*/ ("value" can be 0x1000, 0x2000, 0x3000) ii) dot11config --rxgain /*value*/ ("value" can be 0x000, 0x100, ..., 0x1F00). 

    (3) Another useful feature is to get a copy of 16M raw I/Q (using dot11config -d, the default folder is c:\). So that you can directly read the strength of the raw I/Q signal which can help you tune the gain.

    (4) The radio board matters. We have tried WARP radio and USRP radio (xcvr2450). The communication distances are different.

    (5) The baseband algorithms may matter. We didn't take much effort to optimize the baseband algorithms for communication distance. The baseband is provided as sample code and you are free to do any modification to improve the communication distance.

    B: Antenna

    Improving the antenna should improve the distance in theory because SNR will be improved. But we do not have much experience for different antennas therefore are not able to give suggestions for which antenna to use.

    C: MIMO

    Sorry. We have not released the Sora SDK, RCB firmware and radio solution for MIMO.

    Friday, June 25, 2010 8:53 AM
    Moderator

All replies

  • Dear Iamtoytoy,

    Very glad to hear you have successfully set up the Sora system!

    Answers for your questions:

    A: Communication distance

    (1) Did you try to change the data rate? 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) Did you try to change the gain on RX path? Since we didn't implement any automatic gain control in the sample code, it requires you to tune the gain manually. When the distance is large, you may need to increase the gain. There are two options: i) dot11config --rxpa /*value*/ ("value" can be 0x1000, 0x2000, 0x3000) ii) dot11config --rxgain /*value*/ ("value" can be 0x000, 0x100, ..., 0x1F00). 

    (3) Another useful feature is to get a copy of 16M raw I/Q (using dot11config -d, the default folder is c:\). So that you can directly read the strength of the raw I/Q signal which can help you tune the gain.

    (4) The radio board matters. We have tried WARP radio and USRP radio (xcvr2450). The communication distances are different.

    (5) The baseband algorithms may matter. We didn't take much effort to optimize the baseband algorithms for communication distance. The baseband is provided as sample code and you are free to do any modification to improve the communication distance.

    B: Antenna

    Improving the antenna should improve the distance in theory because SNR will be improved. But we do not have much experience for different antennas therefore are not able to give suggestions for which antenna to use.

    C: MIMO

    Sorry. We have not released the Sora SDK, RCB firmware and radio solution for MIMO.

    Friday, June 25, 2010 8:53 AM
    Moderator
  • Dear Iamtoytoy,

    May I have your email address? I have some questions about the Sora-Setup to ask you and expect you help.

    Thank you very much! 

    Friday, July 09, 2010 3:08 AM