Relay Transmission For Wireless Access Network Based On Complex Networks Theory

As a wireless access network's technology,relay transmission has been widespread concern with the development of wireless communication in recent years.Relay transmission has a great advantage in extending network coverage,extending network life and improving network throughput.The selection of relay nodes is an important problem in relay transmission.It also can be regarded as a multi-hop routing problem or path problem for wireless access network.With a reasonable relay selection strategy,network can effectively improve its performance.Firstly,we consider a class of wireless access networks.In which nodes' location is unchanged,randomly located,and facing the problem of random failure.Based on the scale-free network model in complex network theory,this thesis presents a relay transmission for wireless access network,aiming to solve the problem of random failure.Then the average field theory method and the simulation experiment are used to analyze the degree distribution.The results demonstrate that the degree distribution obeys the power law distribution with power exponent 3.Energy consumption is one of the key factors restricting the development of wireless access network.Based on the proposed relay transmission method,this thesis presents an energy-efficient relay transmission method for wireless access network to reduce energy consumption furthermore.Firstly,in the initial stage,the arrival order of the nodes is controlled.Secondly,in the growth stage,the relay selection range is limited according to the location information to reduce the additional communication loss.Then,in the stage of data transmission,two schemes of random selection and distance optimal selection are presented.Finally,OMNeT++ simulation software is used to analyze the energy consumption of networks with different scale.Finally,cases in which the nodes have some characteristics,such as mobility and the difference of service request are considered.In order to simulate the actual situation,the service requests in wireless access network are divided into three services,which are text,voice and video.Then a weighting utility formula about nodes' number of connection and the distance between two nodes is used to improve the probability selection formula of the preferential selection stage,and a relay method with topology reconstruction mechanism for wireless access network is presented.Simulation results demonstrate that the method can further reduce the energy consumption.