Medium Access control (MAC) is one of the most important, and most
studied, protocol layers in wireless sensor/actuator networks.
Typically, these sensor nodes are resource constrained and the sensor
network appications have timeliness constraints. This makes traditional
techniques like ALOHA and CSMA unsuitable as they are non-deteministic
and power-consuming. CDMA is too complex to be implemented on sensor nodes
while FDMA is unsuitable for perioic messages. Traditional Table TDMA is
deterministic and efficient, which makes it a natural candidate. However,
implementations are memory-intensive which does not make it
very scalable. I will talk about two recent hybrid TDMA-based solutions
proposed by the Real Time Community which are deterministic, scalable and
have power-saving potential as well.