BiC-MAC: Bidirectional-Concurrent MAC protocol with packet bursting for underwater acoustic networks

Underwater communication mainly relies on acoustic waves. Its unique characteristics, such as slow propagation speed and low bit rate-distance product, present both challenges and opportunities for Media Access Control (MAC) protocol design. In existing sender-initiated handshaking based MAC protocols, each successful handshake only allows an initiating sender to transmit single or multiple consecutive packets to its intended receiver. In a long propagation delay environment, these unidirectional transmissions often result in poor channel utilization. By exploiting the channel's characteristics, we present a novel approach of concurrent, bidirectional data packet exchange to improve the data transmission efficiency. To further amortize the high latency overhead, we adopt a packet bursting idea, in which a sender-receiver (S-R) node pair can exchange multiple rounds of bidirectional packet transmissions. We then design an asynchronous handshaking based MAC protocol, which we call BiC-MAC (Bidirectional-Concurrent MAC with packet bursting). Via extensive simulations and comparisons, we show that BiC-MAC can significantly increase the channel utilization and offer performance gains in terms of throughput and delay.