Medium Access Control Protocols For Data Collection-oriented Underwater Acoustic Sensor Networks

Underwater Acoustic Sensor Networks(UWASNs)is an important infrastructure for exploring,observing and developing the ocean.One of the key supporting technologies in UWSNs is Medium Access Control(MAC)protocol,which manages channel resources and allows the nodes in a network to share the common broadcast channel.This paper studies MAC protocols in UWASNs for the application scenario of data collection tasks.In response to the problems of insufficient support for multi-application adaptation or different Quality of Service(QoS)requirements for different regions and relatively single methods for adaptive adjustment of protocols,this paper proposes an adaptive hybrid MAC protocol based on estimation and interception.It supports that different nodes run different types of protocols at the same time to meet different QoS requirements in different regions,and uses protocol adaptation methods to improve performance.According to the characteristics of different types of protocols,we use delay estimation and protocol adjustment methods in the scheduling protocol to adaptively change the protocol parameters and interaction process according to the channel condition and load changes,so as to improve the channel utilization and energy efficiency.And in the reservation protocol,we use passive interception and split transmission methods to reduce conflicts with other protocols and to make full use of channel idle time to reduce end-to-end delay.In addition,we also design a fairness strategy to ensure the fairness of different nodes.The simulation results show that the protocol designed by this paper can better support multi-application adaptation or different QoS requirements in different regions,and has better transmission performance.In order to further improve energy efficiency and solve some protocol parameter setting problems,this paper proposes a cross-layer design with MAC protocols and a communication decision-making method.Through the cross-layer design,the MAC protocol designed by this paper obtains some information such as the channel condition and controls the transmission power of the physical layer.And through a communication decision-making method based on the combination of rules and cases,the protocol can track changes in the external environment,reduce decision errors,and improve energy efficiency.The simulation results show that the decision-making system designed by this paper can achieve higher decision accuracy with lower complexity and lower communication consumption.We also conduct laboratory tests and sea tests to further verify the performance of the designed protocol and decision-making system in this paper.In the laboratory tests,we implement the MAC protocol and decision-making system designed by this paper on the resource-constrained embedded system,which verifies the deploy ability and effectiveness of the design in this paper.In the sea tests,we deploy the scheduling protocol part of the design protocol in this paper in the actual underwater environment,which verifies that the scheduling protocol has better network transmission performance than the comparison protocol and verifies the effectiveness of the design mechanism,in addition the results meet the design expectations.We investigated MAC protocols in UWASNs in this paper.The achievements on technical and engineering have potential applications for data collection-oriented tasks using UWASNs.