A Novel Distributed Medium Access Control and Synchronization for Ad-Hoc Sensor Networks

In this paper, we provide a general framework of distributed medium access control (DMAC) and synchronization for ad-hoc sensor networks with omni-directional antennas. Compared to existing works that focus on minimizing the energy consumption, our design objectives aim to increase the throughput, to lower the latency, and to solve hidden and exposed nodes problem in a traffic-heavy and dynamic environment. DMAC uses different transmission techniques based on the type of outbound packets, to effectively reduce the overhead and complexity of channel access coordination. At its core, DMAC relies on node activate medium access (NAMA) scheduling to coordinate collision-free transmissions. As time synchronization plays a fundamental role in DMAC scheduling, we also design a synchronization scheme tailored to multi-hop networks with heavy traffic and packet loss. We evaluate the performances of the proposed framework via extensive simulations. Our results show that DMAC provides higher system throughput compared with carrier sense multiple access/collision avoidance (CSMA/CA) scheme. In addition, the proposed synchronization scheme can achieve synchronization error within 1 mus in the presence of packet loss and measurement noise, while incurring minimal increment of overheads.