LCO-MAC: A Low Latency, Low Control Overhead MAC Protocol for Wireless Sensor Networks

Abstract

In wireless sensor networks (WSNs), a duty-cycling scheme is typically applied to the medium access control (MAC) protocol to reduce energy consumption due to idle listening. However, this scheme introduces huge end-to-end latency and still suffers from a large control packet overhead. We propose a new MAC protocol with low latency and low control overhead for WSNs use (the LCO-MAC). In our protocol, a DATA packet can be transmitted through multiple hops in a single duty cycle to shorten end-to-end latency. To reduce energy consumption caused by control packet overhead, we force one packet to play more than one role. In the initial transmission period, a control packet acts as an RTS (request to send) for a downstream node and a CTS (clear to send) for an upstream node. In the actual data transmission period, a DATA packet keeps its original DATA role for the downstream node, but also plays an ACK (acknowledgment) role for the upstream node. Our simulation using ns-2 has shown that LCO-MAC enables a notable improvement in energy efficiency and decreases end-to-end latency compared to those of RMAC.