State Coloring Based MAC Protocol For Underwater Acoustic Networks

The lack of resources has become the biggest challenge that countries are facing,so the countries focus on the rich marine resources.There are natural means of production and livelihood in the ocean,including mineral resources,chemical resources and biological resources.Underwater acoustic networks is the key technology of Marine resources exploration and exploitation.In addition,it also has a wide application prospect in military and Marine environmental protection.Media Access Control(MAC)is one of the core technologies of underwater acoustic networks,which is mainly responsible for allocating channel resources and avoiding conflicts during data transmission.However,the underwater acoustic networks have the characteristics of high delay,low bandwidth,high bit error rate,limited energy,multipath effect and dynamic network topology,therefore the MAC protocol of the existing land wireless network can't be directly applied in the underwater acoustic networks.At present,the main goal is to design a high performance MAC protocol which is suitable for underwater acoustic networks.In order to improve throughput,channel utilization and fairness,this paper proposes a new distributed scheduling MAC protocol based on node state coloring technology-State Coloring based MAC Protocol for Underwater Acoustic Networks.In SC-MAC protocol,each node extracts the layer field information from the received hello message to update its own layer,and constructs and maintains its own one-hop neighbor table,then constructs a local layered graph according to the one-hop neighbor table.The data frame or ACK frame learns the status of neighbor nodes to color the nodes in the local layered graph,and schedules the transmission of packets according to the local layered coloring graph.This can reduce the number of control packets,improve the parallel transmission,and effectively avoid effectively the collision between packets.Compared with the contention-based MAC protocol,this protocol does not require the RTS/CTS handshake mechanism to avoid collision,reducing control packets can reduce energy consumption and improve channel utilization.The local layered coloring graph for each node was constructed through the one-hop neighbor table and state of node.Based on the local layered coloring graph,each node implemented as many concurrent,conflict-free transfers as possible.The problem of hidden terminals was solved by eliminating sending data to nodes with potentially collision colors.In order to improve the fairness of the protocol,a fair-based backoff scheme based on fairness is proposed,which gives less backoff time to the nodes that are not easy to preempt the channel.When a node ends sending data or the number of data frames transmitted by a node reaches the maximum value,the backoff time is started and the channel is preempted again after the backoff time ends.This paper compares the performance of the SC-MAC protocol with the R-MAC protocol and the slotted FAMA protocol based on NS3 simulation platform.The simulation results show that the SC-MAC has obvious advantages over R-MAC and slotted-FAMA in terms of end-to-end delay,throughput and average energy consumption.