Dear Joao, There is only one MAC for the IRIS currently, which is BMAC with low power listening and acknowledgments (CCA/CA best effort single hop asynchronous single channel). There are two CA (collision avoidance) algorithms: one is the simple random backoff just like the one used in the CC2420 driver. The other one is a slotted time sync based version where each node makes a guarantee that only at a given time within a time slot (e.g. 1 ms) they will ever start to transmit. This value is monitored by nearby motes (no payload overhead) and they preemptively avoid these time instances. This greatly reduces the chance that two motes will start to transmit within 50-100 microsecs to each other, so the CCA (clear channel assessment) will become much more efficient. This slotted behavior can enabled by defining SLOTTED_MAC.
Miklos 2009/3/27 João Paulo Amaro da Costa Luz Carneiro <[email protected]>: > Hi, > > What are the different MAC implementations available for the IRIS mote > in tinyos2.1. > Are they all packet based or is there any TDMA protocol. > If you could also provide any performance results you have that I > could use to make a performance comparison between the protocols would > be great. > > Regards, > > Joao > _______________________________________________ > 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
