Reliability And Security Analysis For Green And Efficient Cooperative Communication Transmission

With the rapid development of the Internet of Things and cloud computing,the number of communication devices and communication data traffic surge,which brings unprecedented challenges to the wireless communication network.To achieve a wider transmission bandwidth and a higher transmission rate,the traditional method is to expand the spectrum resources by increasing the communication transmission frequency,or to provide efficient and stable transmission by fixing the location of the base station and designing a fixed spectrum resource allocation method.However,the shortcomings of these methods are also very obvious:(1)Higher frequency electromagnetic waves mean shorter transmission distances,which further reduces the coverage radius of base stations,further increases the number of base stations required,and further increases the cost of base station deployment;(2)Currently available Wireless spectrum resources are very scarce,the utilization rate of wireless spectrum resources is low,and the fixed spectrum allocation strategy does not match the spectrum demand;(3)The volume of the mobile terminal and the capacity of the battery are limited,which limits the application of the multi-antenna technology,thus shortening the lifetime of the wireless network.To achieve efficient use of wireless resources in wireless communication networks,and expand coverage,prolong lifetime,enhance the security and reliability of wireless communication,this paper mainly focuses on NonOrthogonal Multiple Access(NOMA),Energy Harvesting(EH),Cognitive Radio(CR),Physical Network Coding(PNC),and other related technologies.The main contributions and innovations of this paper are as follows:Firstly,considering the nonlinear EH technology,a NOMA system based on Power-Splitting(PS)full-duplex(FD)user cooperation is proposed,the accurate closed-form results of the outage probability are deduced,the approximate results under high Signal-to-Noise Ratio(SNR)are given,and the optimal power allocation factor is derived to minimize the outage probability.Finally,the influence of self-interference on outage performance is discussed,and it is found that self-interference is sometimes beneficial to outage performance.Secondly,for the cognitive network composed of multiple Decode-and-Forward(DF)relays and eavesdroppers,a new relay selection scheme is proposed to improve the security and reliability of the system.The cumulative distribution functions of legitimate channels and eavesdropping channels are derived in detail under the relay selection criteria.Finally,the accurate closed-form results of outage probability and interception probability of the system are given.Through theoretical analysis and simulation results,it can be seen that although the relay selection criterion is given based on the legitimate channel and the eavesdropping channel,the reliability has nothing to do with the eavesdropping channel,and the security has nothing to do with the legitimate channel.And the security performance will always improve with the increase of the number of relays,but the reliability will not.Then,considering the max-min relay selection criteria,the data forwarding and relay selection process are designed for the bidirectional relay system with overlay cognitive network,and the exact closed-form result of outage probability and approximate expression under high SNR are derived.Through simulation analysis,it is found that the outage probability will reach a threshold under high SNR.Finally,considering the characteristics of PNC and NOMA technology,combining superposition coding and bit-level XOR coding,a hybrid two-stage transmission protocol of PNC and NOMA is proposed for the two-way transmission system,which improves the transmission efficiency of the system.The closed-form results of system outage probability are deduced,and the power allocation factor is optimized under the scenario of perfect and imperfect Serial Interference Cancellation(SIC)technology.Compared with two other two-phase transmission protocols and a three-phase transmission protocol,the superiority of the proposed transmission strategy is verified.