Research On MAC Protocol Of UWSN With Low Energy Consumption

In the face of the rapid increase in human demand for resources and the dwindling availability of land resources,people began to pay attention to the potential of the oceans.How to exploit marine resources has become a top priority for researchers.As an important tool to exploit such resources,Underwater Sensor Networks have also been developed vigorously.Underwater Sensor Network refers to a self-organizing network composed of wireless acoustic communication among nodes that are deployed to the water with communication and computing capabilities.It can be used in marine disaster monitoring,marine environmental protection and marine resource exploration,etc.The MAC protocol,which is located in the data link layer of Underwater Sensor Networks,is responsible for allocating channels to the nodes and has a significant impact on the performance of the underwater sensor networks.Since nodes carry limited energy,the design of MAC protocols must focus on energy issues.In order to design a MAC protocol with low energy consumption.In this paper,the following work is done.(1)A dynamic backoff MAC protocol based on handshake mechanism,DBMA-SFAMA,is proposed for the case of high data generation rate in the channel.This protocol adds the RTT mapping table to the Multi ACK-SFAMA for sending ACK packets,and can be more flexible and dynamic to adapt to the underwater network environment by using the network-wide update of the RTT mapping table to flexibly adjust the evasion time when the nodes are in conflict and avoid the channel waste.In the case of high data generation rate,compared with Multi ACK-SFAMA,DBMA-SFAMA can better achieve the purpose of reducing energy consumption by determining the evasion time according to the propagation delay of different nodes in the network.(2)To solve the problem that DBMA-SFAMA consumes slightly high energy when the data generation rate is low,this paper also proposes HDBMA-SFAMA.The HDBMA-SFAMA requires the sender to use the simplest Aloha when the data generation rate is low,and then use the monitoring node at the sender to monitor the channel traffic in real time and send a signal to remind the sender to switch to DBMA-SFAMA when the data generation rate is high.When the monitoring node detects that the data generation rate in the channel is low,it sends a signal again to remind the sender to switch back to Aloha.This is due to the fact that Aloha can send data directly at any time without regard to channel conditions,and performs well in the case of low data generation rates and low collisions.And when the high data rate,serious when collision,use DBMA-SFAMA.The combination of the two protocols can achieve low energy consumption regardless of the data flow in the channel.(3)The above protocols are simulated in the Aqua-Sim simulation platform.The performance metrics of several protocols are compared in terms of throughput,latency and energy consumption,using the data generation rate as the independent variable.The simulation results show that DBMA-SFAMA has better performance at higher data generation rate,while HDBMA-SFAMA can meet the condition of low energy consumption regardless of the data generation rate in the channel,and also has better effect in increasing the throughput and reducing the delay.