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Cannot receive 'sdradhoc' beacon and send/receive the frame whose rate is 36~54 Mbps, with umxsdrab.exe RRS feed

  • Question

  • Hi,

    while doing some experiments, we discovered some odd behaviors.

    1. Sora machine cannot receive 'sdradhoc' beacon from the other Sora machine

    It is expected that

    while one Sora machine is set to ad hoc mode with umxsdrab.exe -f 2422 -s 44 ,

    (This is a/g mode, and we chose 44 MHz as the sample rate because 40 MHz didn't work at all)

    the other Sora machine can receive that beacon with the client mode of umxsdrab.exe -f 2422 -s 44 .

    But actually, although Sora machine was able to receive 6Mbps beacon from AP (Cisco 1142N, configs customized),

    it cannot receive the beacon from 'sdradhoc'.

    (Using Omnipeek, we confirmed that the rate of 'sdradhoc' beacon is 6 Mbps.)

    We cannot figure out the reason of this behavior.

    2. Sora machine cannot send/receive the frame whose rate is 36~54 Mbps

    With umxsdrab.exe, we can adjust the rate of TX frames at runtime.

    And it is ok to use ~24 Mbps rate, confirming with AirPcap Nx & Omnipeek.

    But, when we increase the TX rate to 36~ Mbps, the packet seems to be corrupted.

    And also, Sora seems to be unable to receive the frame with the rate of 36~ (or 24~) Mbps.

    Are these the common behavior of current version of Sora SDK & hardware?

    Thank you for your answer in advance.

    Jihoon

    Wednesday, September 26, 2012 5:02 AM

Answers

  • When the data rate goes up, the requirement of SNR also goes up. Many factors can affect SNR, for example, your parameter setting (frequency offset, tx gain, rx gain, distance between two antennas ...), quality of certain piece of radio hardware (it differs from hardware to hardware). If the SNR is low under a certain configuration and certain piece of hardware, the highest rates will be difficult to reach.

    -Jiansong

    Thursday, October 11, 2012 4:06 AM