Energy-efficient contention-resilient medium access for wireless sensor networks

Wireless sensor networks have distinct requirements on the Medium Access Control (MAC) protocol, including energy-efficiency, low latency, contention-resilience, etc. The trade-off between energy-efficiency and latency is usually addressed by adding synchronization overhead and/or radio hardware, and most proposed MAC do not efficiently handle the "spatially-correlated contention" common in typical sensor applications, i.e., close-by nodes reporting a common event simultaneously. We propose a cross-layered MAC protocol, which employs a Dynamic Forwarder Selection technique, to improve both energy-efficiency and delay without requiring additional synchronization or radio hardware support. Furthermore, our MAC can efficiently handle spatially-correlated contention and scales well with the network density. Results show that our MAC provides significant energy-savings, low delay and high network throughput.