CSMA-MPS: a minimum preamble sampling MAC protocol for low power wireless sensor networks

Medium access protocols for wireless sensor networks are especially challenging because the receiver of a sensor node in a distributed multi-hop network must be turned off most of the time to save energy. Existing solutions either try to solve this problem with a very low power wake-up receiver or by different means of synchronization using methods such as preamble sampling or periodic synchronisations. Here presented CSMA-MPS approach is a MAC layer protocol, which is optimized for low energy consumption by a very efficient wake-up mechanism. A second difference is the use of radio transceivers with a high over the air bit rate of 1 Mbps and short transmit and receive turn-around times. This enables the proposed protocol to operate much more efficiently compared to low to medium bit-rate transceivers used in traditional sensor networks. Simulations and experimental results with existing off-the-shelf hardware show that the average power consumption of the transceiver alone can be as low as 35 μW by forwarding packets at a rate of 10 packets per minute and by guaranteeing a hop-to-hop delay of 400 ms.