Research On Dual Channel Hybrid MAC Protocol For Underwater Acoustic Networks Based On TDMA And Transmission Time Scheduling

With the need of marine resources and rights,the need to communicate using underwater sound waves is increasing.At present,underwater acoustic communication has been widely used in the military and civilian fields.Medium Access Control(MAC)is a key technology of underwater acoustic communication networks,which determines the way nodes share water acoustic channel resources.Its performance directly affects the overall performance of underwater acoustic communication networks.The narrow bandwidth,long time delay,multipath interference of the underwater acoustic channel and limited node energy are the main factors affecting the performance of the underwater acoustic MAC protocol.Handshake is a common method to avoid collision in competitive protocols,but the traditional handshake mechanism only allows serial communication,resulting in low channel utilization,so there is room for improvement in throughput,packet delay and energy utilization.In order to overcome this shortcoming,some new MAC protocols in underwater acoustic networks take advantage of the prolonged propagation time of underwater acoustic channels and allow multiple nodes to shake hands and transmit data concurrently in a transmission cycle by reasonably scheduling the transmission time of source nodes.However,RTS/CTS can not completely avoid conflicts by using random transmission.To solve the above problems,this paper proposes a dual-channel hybrid protocol based on the combination of TDMA and transmission time scheduling.This protocol uses pipeline to realize handshake and data transmission,which can improve transmission efficiency while eliminating conflicts.The research work of this paper is as follows:1.The protocol stack of underwater acoustic communication network,the typical characteristics of underwater acoustic channel and the influence of these characteristics on underwater acoustic communication performance are introduced.2.Introduce some existing underwater acoustic communication network MAC protocols,and four indexes to measure the performance of the MAC protocol.At the same time,introduce the Aqua-Sim simulation platform,and simulate and analyze some of the protocols under Aqua-Sim.3.To overcome the shortcomings of existing protocols,a dual-channel hybrid MAC protocol based on the combination of TDMA and transmission time scheduling(TDTS-MAC)is proposed.The protocol uses two-channel communication,uses optimized time division multiplexing method to send handshake signaling in one channel,combines response signaling with handshake signaling,and uses optimized transmission time to send data in parallel in another channel.Both of them are carried out in parallel in pipeline mode.4.The new MAC protocol is simulated on Aqua-Sim platform,and the performance of the new MAC protocol is compared with that of some existing MAC protocols.The experimental results show that the new MAC protocol can effectively improve throughput and transmission success rate,reduce average energy consumption at the expense of end-to-end packet delay.