An Investigation of Packet Concatenation in Sensor Networks

In wireless sensor networks (WSNs), the multi-hop MAC protocol combines duty cycling radio and forwarding packet via multiple hops (i.e., multi-hop forwarding) to achieve a good balance between energy and latency efficiency. The multi-hop MAC protocol has been proven to outperform other traditional duty cycling protocols, which allow forwarding a packet at most one hop in an operational cycle. Among state-of-the-art multi-hop protocols, M AC², which additionally leverages packet concatenation technique, achieves the best performance in normal environments (i.e., without considering noisy). The concatenation technique, which lets several small packets be concatenated into a bigger one before sending out at a node, effectively saves control overhead and shortens delivery latency in WSNs. However, the packet concatenation may downgrade the performance of the network in the noisy environment since the cost for retransmission is high. In this paper, we investigate the negative effect of the noisy level of environment on the efficiency of M AC². We observe that in the noisy environment, M AC² still keeps the reasonable performances, which are better than the one without concatenation (i.e., the demand-wake up MAC DW-MAC). The simulation results using ns-2 confirm our observations.