Sora Simultaneous Transmission RRS feed

  • Question

  • We are currently using Sora for a project and it requires accurate synchronization between multiple machines.

    Here is some information about our machine setting:
    Three PC are used. One as controller and other two as clients.
    Each of them has Sora RCB plugin (single antenna version). 
    Radio Frontend is WBX from ettus research.

    Window XP installed and our implementation is based on 802.11a user mode brick version.  

    Here is the problem:
    Controller machine broadcast one packet. After client machines receive packet from the controller, they will send response at the same time. 
    For example, machine A reply response at t1 and machine B reply response at t1' where the difference between t1 and t1' is within 2 microsecond second.

    We are not able to achieve such synchronization and here is our current implementation
    After broadcasted packet was received and decoded correctly. Both clients will wait for 100 signal blocks then start transmitting the response packet. The response packet is modulated and cached in the hardware.    
    First, we would like ask if we are in the right track or not?
    Second, if it is the right direction to go. What would be the potential issues we have to take care?

    We would appricate if you can give us any suggestions.
    Thursday, November 20, 2014 12:56 AM

All replies

  • Hi MYYE20,
    It is very hard to achieve specific delay as you requested. There are many waiting time during to whole process from signal received by antenna and completely decoded by software, such as DMA operation, RX buffering, OS thread scheduler, etc. So I would argue that your requirement is not realistic or not fit for current platform. Please carefully investigate existing MAC protocal before you design your own.

    If you really want to do this, you should have the method to measure the t1 and t1' accurately, eg. by an equipment, and then try hacking the hardware or software.

    Thanks, -Qi
    Thursday, November 20, 2014 3:28 AM