Efficient mac protocol for handling triple hidden terminal problems of multichannel underwater sensor networks

Abstract

As multi-channel communication is becoming more and more common in Radio Fre- quency (RF) arena, acoustic communication protocols have also started to adopt the same concept to utilize multiple channels in Underwater Sensor Networks (UWSN). Although the deployment of multi-channel increases throughput significantly, it also opens up the possibility of collision occurrence due to the hidden terminal problem. In particular, Triple Hidden Terminal (THT) problem, a phenomenon characterized by collision occurrence due to multi-hop, multi-channel communication with long propagation delay, persists more dominantly in UWSN. Existing MAC protocols try to mitigate the adverse effect of Triple THT without utilizing the information of propagation delay that may be exploited to improve the performance of UWSN significantly. Hence, this research work proposes a Cooperative Underwater Multi- Channel MAC protocol with delay mapping and channel allocation assessment. A new Channel Allocation Matrix (CAM) has been introduced for estimating prop- agation delay ensuring enhanced channel utilization. In this scheme, each node maintains a delay mapping database, based on which senders and receivers perform a scheduling algorithm before initiating any transmission. This mapping helps a node to predict whether it’s upcoming packet transmission will collide with other nodes’ transmission or not. In brief, the objective is to ensure successful transmission by mitigating problems in multichannel underwater sensor networks as well as to enhance the channel utilization with the benefit of delay mapping and channel allocation assessment. Simulation results, carried out for performance analysis, show that the proposed MAC protocol is more efficient in terms of network throughput, energy consumption, end to end delay, packet delivery ratio, packet loss ratio, collision probability and fairness index compared to the contemporary cooperative underwater multichannel MAC (CUMAC) protocol and RTS/CTS based multichannel MAC protocol.