An Energy-Efficient Hash-Based MAC Protocol for LSN

In this paper, we introduce H-MAC (Hash-based Medium Access Protocol), a collision-free, energy-efficient MAC protocol designed for Linear Sensor Networks (LSN) with applications to the Internet-of-Things (IoT), In our proposal, the LSN is divided in grades composed of nodes located at the same hop-distance to the sink. Nodes in the same grade follow a synchronized duty cycle to transit from the different operation modes (transmission, reception, sleeping). In order to transmit packets from one grade to the next, nodes use pipeline scheduling to coordinate transmissions between adjacent grades. During a transmission slot, H-MAC employs hash functions to implement a distributed election whose winner can access to the channel in an interference-free fashion. Extensive simulation results show that H-MAC outperforms state of the art proposals in terms of throughput, source-to-sink packet delay, packet loss probability and energy consumption. This is particularly true in scenarios where the LSN has from medium to high node density, which is a common condition in the context of the IoT.