Research On The Relay Selection Algorithm In Wireless Cognitive Network Based On Channel Error Constraint

Recently,with the increasing development of wireless communication technologies,higher requirements have been put on the use of spectrum resources.The Cognitive Radio Network(CRN)solves the shortage of spectrum resources,while there are limitations such as fast signal fading and small network coverage.Therefore,it is necessary to introduce the relay technology and use its forwarding characteristics to ensure the accuracy and security of information transmission in the wireless communication process,thereby improving the performance of the cognitive radio network as a whole.However,there are certain correlations between channel quality and system power of different relay links in CRN.In order to further ensure lower power consumption and obtain higher utilization of spectrum resources,it is necessary to study regional relay cooperation methods in cognitive wireless networks.In this paper,the following work is done for the research of the selection algorithms for some collaborative relays:(a)Aiming at the problem of excessive transmit power consumption caused by full cooperative relaying in wireless relay networks,and the attenuation of system characteristics caused by channel estimation errors in complex environments,regional collaborative relay selection algorithm is proposed based on bounded constraints of channel estimation error norm.At first,in order to reduce the power consumption of the full collaborative relay system,the regional collaborative relay system model is analyzed and constructed.At second,the constrained channel estimation error satisfies Gaussian property and norm bounded.And an optimal algorithm for relay selection is obtained,through solving the minimum power consumption satisfying the above constraint conditions.Then,using the local relaxation and sparse lifting theory,the optimization algorithm for partial relay selection is solved by iteratively solving the non-convex problem relaxation for the convex problem,which reduces the computational complexity.The research results show that the algorithm not only reduces the system resource consumption in the cooperative relay network,but also improves the resource utilization rate and is more robust in complex environments.(b)Aiming at the problem of eavesdropping prevention in wireless communication networks,a regional relay selection algorithm based on the communication security rate and channel estimation error constraint is proposed for the purpose of optimizing transmit power.Firstly,we construct a regional collaborative relay system model under eavesdropping scenarios with security constraints.Secondly,regional collaborative relay algorithms under constraint of confidentiality are proposed,in order to minimize the power consumption and increase the overall security of the system.Then,through the technical methods such as convex approximation and Taylor series expansion,the original problem is relaxed into a convex optimization problem and solved for solving,which reduces the computational complexity.The result of the research shows that this algorithm not only has stronger security and confidentiality performance than the regional collaborative relay selection algorithm of ideal channel,but also makes regional collaborative relay systems adapt to more complex environments.