none
Question about handling timer for back-off, sifs etc... RRS feed

  • Question

  • Hi all, 

    I'm trying to understand the SORA code. 

    I'm starting from umxsdrab code. 

    Now I might know the basic operation of packet transmission and receive.

    And, we succeed to receive the correct packets via hwveri and associate with a commercial AP via umxsdrab (in 2.4 GHz, not in 5 GHz).

    I have three simple questions. 

    1. I cannot find any code about timer or deferring handler for back-off, sifs, difs, aifs, and so on which are the basic operations of 802.11. Do you have any suggestions to better understand the parts implemented in SORA? or should we implement those operation my ourselves?

    2. The second question is about AGC (Auto gain control). I found that the HwVeritest tool have the AGC function. However others, i.e., umxsdrab or umxdot11, do not support AGC operation yet. Am I right? 

    3. By using umxdot11, SORA failed to receive packets even if we change rx/tx gain and rxpa via dut.exe. Do we need to set the other parameters? And based on the umxdot11 code, even if we set the txgain, the code use the default txgain value. Am I right?

    Thank you .!



    • Edited by Okhwan Lee Wednesday, September 26, 2012 2:10 AM
    Wednesday, September 19, 2012 7:40 AM

Answers

  • Hi Okhwan Lee,
    Sorry for late response.
    About your questions, assuming they are related to SoraSDK version 1.7
    1. Currently we have no back-off feature. The time limition about SIFS, DIFS in 802.11a/b protocol are approximately implemented. If you want to check the detail code, you can refer the class 'TEnergyDetect' in cca.hpp for 802.11b brick implementation, or the function 'BB11ARxCarrierSense' in arx_cs.c for 802.11a implementation. In general we set the max/min boundary for samples used in carrier sense phase to achieve time control.
    2. umxdot11 is a simple 802.11a/b frame generator and monitor, they are used for channel dianostic and signal processing debugging, so expected no AGC.
    3. If you want to adjust rxgain/rxpa/txgain, you can use 'dut.exe' _after_ you start umxdot11 (you should open another cmd window).

    Any questions, please let us known.
    • Marked as answer by Qi LuoEditor Tuesday, December 18, 2012 7:07 AM
    Tuesday, December 18, 2012 7:07 AM
    Answerer

All replies

  • I obtain some answers on this topic by myself. 


    2. umxsdrab supports AGC but umxdot11 does not.

    3. Based on the forum searching, I thought that we can set the tx gain via dut.exe when we use umxdot11. However it use default txgain, 0x1000, even if we change tx gain of dut.exe setting.

    Anyway, I do not have any answer about timing operation for back-off, sifs, difs and so on in SORA code.

    If you have any idea, please let me know.

     Thank you.

    Wednesday, September 26, 2012 2:20 AM
  • Hi Okhwan Lee,
    Sorry for late response.
    About your questions, assuming they are related to SoraSDK version 1.7
    1. Currently we have no back-off feature. The time limition about SIFS, DIFS in 802.11a/b protocol are approximately implemented. If you want to check the detail code, you can refer the class 'TEnergyDetect' in cca.hpp for 802.11b brick implementation, or the function 'BB11ARxCarrierSense' in arx_cs.c for 802.11a implementation. In general we set the max/min boundary for samples used in carrier sense phase to achieve time control.
    2. umxdot11 is a simple 802.11a/b frame generator and monitor, they are used for channel dianostic and signal processing debugging, so expected no AGC.
    3. If you want to adjust rxgain/rxpa/txgain, you can use 'dut.exe' _after_ you start umxdot11 (you should open another cmd window).

    Any questions, please let us known.
    • Marked as answer by Qi LuoEditor Tuesday, December 18, 2012 7:07 AM
    Tuesday, December 18, 2012 7:07 AM
    Answerer