Dynamic Backoff Underwater Acoustic Network MAC Protocol Based On Handshake Mechanism

The study of underwater acoustic communication network(UWAN)has broad application prospects and practical significance.The underwater environment and the particularity of underwater acoustic channel determines that the terrestrial wireless network protocol difficultly be applied to UWAN directly.So,we need to design a suitable protocol stack for underwater acoustic communication.The current research of UWAN is in the immature state,and still need a lot of validation studies.MAC protocol is one of the important parts of UWAN and one of the research emphases of UWAN,which determines the channel access and even affects the quality of the whole network.Designing a MAC protocol that is highly adaptive to the network environment and exhibits high performance is the current goal.Domestic and international scholars put forward many MAC protocols,but mostly stay in the theoretical derivation and simulation verification stage,lacks the test validation in the real underwater acoustic channel.So,to strengthen the actual environment of underwater acoustic communication network protocol testing is another issue that we need to focus on as well.This paper points out the research priorities and challenges through the development situation of UWAN,and clarifies the background and significance of the research.Mainly studied the MAC protocol in the UWAN,and classifies and analyzes the MAC protocols that have been proposed at home and abroad.This paper focus on the MAC protocol based on a handshake mechanism,summarized the existing improvement ideas handshake mechanism,and put forward a kind of dynamic back off protocol called DB-MAC based on handshake mechanism.The new protocol improves the utilization of underwater acoustic channel from two aspects.On the one hand,the dynamic update RTT and the number of packets currently transmitted are used to optimize the backoff time of the contention node.On the other hand,the unprocessed handshake request is stored in a queue called "pending RTS",and once the round of data sending and receiving is completed,the CTS packet is directly responded to the corresponding node,reducing the overhead of contention node sending handshake packet again.The protocol is simulated based on the UAN module of NS3 network simulation platform and compares the simulation performance with other three classical underwater acoustic network MAC protocols.Analysis of the differences in throughput,delay,power consumption and transmission success rate of several MAC protocols under different load conditions.Besides the simulation demonstration,this article has tested the improved protocol and other several classic protocols in the practical underwater acoustic channel based on the UWAN experimental platform developed by our laboratory.And also,analysis and compare the differences in throughput,delay and transmission success rate.Further validate the theoretical analysis and simulation results.DB-MAC has achieved better network performance in both simulation experiments and real underwater acoustic channel experiments.