In general, lower level collision detection should minimize the number of attempts to send simultaneous messages. But if your two slave motes are out of range of each other they won't detect a collision. Or if they consistently try to transmit at _exactly_ the same time I guess they wouldn't detect a busy channel either.
In my testing of mica2's I did something very similar to your system, sending a request from the base-station and having each re-Mote attempt to respond immediately. I didn't find a lot of dropped messages. I was not able to test multiple micaz's, so my results don't indicate a (larger) problem. If your system depends on the call-and-response model, probably having a short random delay before responding is your best option. MS Breno Guimarães wrote: > Hi, > > I'm working with MicaZ motes on TinyOS 2.0.1. > > My application is simple. I have one mote sending a broadcast message > and other two responding to the first whenever they receive any message. > Therefore, the first mote receive two messages almost at the same time. > > When running on TOSSIM, I noticed that they respond exactly at the same > time. As the first mote can't receive two messages at the same time, it > drops one of the messages. > > I solved this problem by using a timer on each mote that acts as a > "clock". The clock frequency is calculated using the node ID number, so > every mote respond with different times. > > That works very well on the simulation and there was no problem when I > tried on real motes. > But that seems a poor solution as it is made on software. > > My question is: Is there any hardware that avoid that kind of problem on > micaz? If there isn't, is there any other better software solution? > > Thanks in advance, > > Breno Rodrigues Guimaraes > Federal University of Minas Gerais, Brazil. > > > ------------------------------------------------------------------------ > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
