Research On The Resource Allocation Algorithm Of Underwater Acoustic Cooperative Communication Based On Relay Selection

In recent years,the research of underwater acoustic communication technology has attracted more and more attention,because of the increasing of military application and the development of marine resources.Different from the terrestrial radio communication environment,the underwater acoustic channel has the characteristics of severe frequency selective fading,which means available spectrum is very limited.Meanwhile,high background noise in marine environment,multipath effect influence by reflection in seabed,propagation delay and other unfavorable factors,cause high bit error rate and low communication rate.Cooperative communication technology can effectively resist the influence of frequency band,long time delay and multipath fading,and effectively alleviate the current situation of underwater spectrum resources.Through the relay based cooperative communication mode,it forms a virtual multiple input multiple output(MIMO)system,which is helpful to reduce the system cost,expand the communication range and improve the communication quality.In order to utilize the scarce spectrum resources efficiently,cognitive underwater acoustic technology,which is similar to the basic idea of cognitive radio technology,emerges as the times require.The application of underwater acoustic technology can availably realize the spectrum management and adapt to the underwater dynamic spectrum environment.In this paper,firstly,the background of the research is analyzed,and the underwater acoustic characteristics and concepts are introduced.The problems in underwater acoustic communication: frequency selective fading,multipath effect,Doppler shift and high background noise.Then,the basic principles of cooperative communication and cognitive spectrum sensing technology are analyzed,which lays a good foundation for research on cognitive underwater acoustic cooperative communication.Secondly,the problem of single relay selection and power allocation in cognitive underwater acoustic system is studied.In Underlay mode,the cognitive users sharing scarce underwater spectrum resources,in order to adapt to the changing environment of underwater acoustic communication,we use the trust parameter to evaluate the quality of relay.In order to improve the speed of communication,the system throughput is taken as the objective function.Compared with other strategies,the algorithm in this paper can improve the throughput of the system by nearly 20%.Finally,the joint optimization problem of multi-relay cooperative underwater acoustic communication is analyzed.In case of shortage of spectrum resources,severe decline and long time-delay in underwater acoustic communication,the trust parameter participates in the cooperative sensing through the proportion weighting method,which can effectively improve the accuracy of sensing.At the same time,network interference limits and residual energy are used to construct utility functions in multi-relay cooperative networks.From the view of power optimization and residual energy consumption,relay selection and power optimization based on genetic algorithm make the network energy consumption more balanced.The network lifetime has been increased several times,and the computational complexity decreased exponentially.