Research On MAC Layer Protocol In Power Line And Wireless Cooperative Communication System

Wireless communication and power line communication can be widely used in smart grids and home networks.Wireless communication is flexible to access network,but high-frequency signals are easily blocked by obstacles such as walls;power line communication uses wire existing in the wall to transmit signals,which can compensate the disadvantage of wireless signals.Therefore,wireless and power line cooperative communication can complement each other,save construction costs,ensure a certain coverage,and meet the needs of different services.Wireless networking and power line communication hybrid networking technology mainly focuses on the key technologies of the physical layer of power line and wireless cooperative communication,and less related issues such as MAC layer cooperation.Therefore,in order to meet the needs of wireless communication and power line communication hybrid networking,this paper proposes two kinds of MAC layer backoff algorithms for power line and wireless cooperative communication based on traditional power line communication and wireless communication MAC layer CSMA/CA(carrier sense multiple access with collision avoidance)algorithm,which are selective CSMA/CA algorithm based on the first idle first expropriation mode and parallel CSMA/CA algorithm based on full idle charge mode.The paper firstly compares and analyzes the existing CSMA/CA algorithms in IEEE1901 and 802.11 standards.Then,the paper gives the flow and main content of the two backoff algorithms.In the selective CSMA/CA algorithm,as long as one of the wireless and power line channels is idle,it can be used to transmit packets;Parallel CSMA/CA algorithm requires two channels to be idle at the same time and can be used to transmit packets.Based on the performance model of the decoupling assumption,the paper establishes two system analysis models of CSMA/CA algorithm,which can calculate the throughput and collision probability of the two algorithms by using the simultaneous nonlinear equations.The paper also analyzes the delay performance of the two backoff algorithms.Finally,the paper uses algorithm simulation to verify the effectiveness and reliability of the system analysis models of the two algorithms.Compared with the CSMA/CA algorithm in wireless and power line communication,the selective CSMA/CA algorithm can improve the network throughput and ensure the effectiveness of the network and the parallel CSMA/CA algorithm can significantly reduce the collision probability and improve the reliability of the network.The paper also simulates the effects of parameters such as delay counter and contention window on system throughput.