On Tue, Jul 24, 2012 at 6:56 PM, 최익성 <[email protected]> wrote: > Dear tinyos developers. > > I have a basic question about collision detection at transmitter. >
Its CSMA/CA not CSMA/CD so it is collision avoidance. > In CSMA/CA, transmitter transmits the frame. If there is a collision, the > transmitter tries to transmit the frame after random backoff time. > > How can the transmitter detects the collision? > Typically this kind of thing is implemented in h/w. You don't specify what h/w you are using... (Yes, it would have been helpful if you told us the specifics of what h/w you are using). So I'm assuming the telosb with the cc2420 radio. the cc2420 hardware does Clear Channel Assessment and provides status bits that tell the driver what is happening. I believe if the channel is busy it is up to the driver to handle the back off. I would suggest you take a look at the cc2420 manual (pg 50) and look at the cc2420 driver where it deals with CCA and possibly the STXONCCA command strobe. > Thank you very much. > > Sincerely Yours, > > Ick-Sung Choi. > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > -- Eric B. Decker Senior (over 50 :-) Researcher
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