Performance Analysis And Technical Research Of Multihop Relay Network

Relay technology can improve throughput and coverage,which makes it one of the key technologies for the next generation of wireless communications.In multi-hop relay networks,one of the basic problems in the research of relay-related theories is how to analyze and measure the theoretical performance of different relay transmission systems.Based on the background of multi-hop relay network scenario,this dissertation analyzes network performance under different system models and related technologies,including the following aspects:Firstly,we consider the degrees of freedom(DoF)of the 2x2x2 multiple-input multiple-output(MIMO)interference network with arbitrary antenna configuration and practical rank-deficiency.Different from existing researches on the 2x2x2 MIMO interference model,the antenna number can be arbitrarily different at the transmitters,relays and receivers simultaneously and the rank of the channel matrix can be arbitrarily different.The exact sum DoF of this scenario is calculated,with the finishing of outer bound and the detailed proof of achievability,respectively.For different configurations of antennas and ranks,the outer bound is proved mainly by min-cut outer bound and the achievability is presented with effective schemes which use combinations of Zero-Forcing(ZF),Zero-Forcing over broadcast channel(BC),Interference Alignment in X channel(X)and Aligned Interference Neutralization(AIN)to match the outer bound.The traditional aligned interference neutralization scheme is modified in this paper to maximize the utilization of signal space overlap.Some related earlier works can be seen as special cases of our research.Second,we investigate the theoretical performance analysis of opportunistic scheduling for dual-hop cognitive relay network with multiuser in the secondary system.Different from the existing work,we take the consideration of primary user's interference with opportunistic scheduling technique and theoretically derive the influence of the interference from primary transmitter for the scenario.The cumulative distribution function(CDF)of signal-to-noise ratio(SNR)is formulated and the exact close-form expression of the cognitive relay network outage probability is derived.After calculating the asymptotic outage probability in high SNR regime and asymptotic error probability,we provide an adaptive power allocation scheme in the secondary system to optimize the capacity of system.It is confirmed that the opportunistic scheduling technique for multiuser has a positive influence on the performance of cognitive networks.Moreover,the adaptive power allocation can also promote system performance.Finally,numerical simulations are provided to support and directly reflect the correctness of our analytic results.Third,we study the problem of relay selection and the analysis of system performance considering co-channel interference in cognitive relay network.In this paper,we consider the co-channel interference in the previous research without considering other issues such as primary-user interference or the secondary-receiver noise interference.The three kinds of interference are considered simultaneously and the system is implemented based on the criterion of maximum and minimum relay selection Relay selection.Then,the dissertation gives the solution method and partial solution of the sub-system outage probability in this system model.Due to the complexity and inhomogeneity of the results due to multiple disturbances,the results of the disruption of the article are finally presented through numerical simulation of the system,and the trend of the interruption probability of the system is explained and analyzed.Finally,the full text is summarized,and look forward to the future research work.In this paper,some advanced technologies for multi-hop relay network performance analysis and technical research as a research goal,both in theory and in practice will have far-reaching significance.