Research On Key Technologies Of Adaptive Multi-Antenna Selection In Wireless Communication Systems With Limited Feedback

With the continuous upgrading of wireless communication technology,the variety of mobile services continues to increase,and the number of communication terminal devices also grows dramatically,leading to a constant increase in the demand for wireless data traffic and network coverage.As one of the research hotspots in wireless transmission,multi-antenna technology can achieve the enhancement of system transmission rate,the improvement of spectrum utilization,and the expansion of network coverage.However,multi-antenna transmission usually requires knowledge of system channel state information(CSI).Considering the resource limitation in the practical limited feedback system,the accuracy of feedback CSI is under the effect of feedback overhead.Meanwhile,the change of the number of active radio frequency(RF)antennas also brings changes in the accuracy of CSI and system power consumption,etc.In addition,because of the broadcasting characteristics of wireless communication systems,the multi-antenna wireless transmission is vulnerable to eavesdropping and interference.Therefore,system performance such as reliability and security of multi-antenna transmission is jointly constrained by the number of active RF antennas and limited feedback.Hence,with the aim of improving the effective throughput,effective energy efficiency(EE),effective secrecy throughput,and security-reliability tradeoff(SRT)performance of multiple antenna communication,this dissertation studies the adaptive multip-antenna selection technology in the limited feedback system.The main research contents and innovations of this dissertation are as follows:Firstly,for the limited feedback problem in a multi-antenna system,the channel fading thresholdbased multi-antenna selection(CFT-MAS)scheme is proposed,and the conventional channel fading threshold-based single-antenna selection(CFT-SAS)scheme is considered as a baseline.Since both two schemes are not optimized for channel fading threshold,they are also denoted as non-optimized CFT-MAS(NOCFT-MAS)and non-optimized CFT-SAS(NOCFT-SAS).The effective throughput defined as the difference between the data transmission rate and the feedback rate is employed as the performance metric for analyzing and comparing the effective throughput performance of the NOCFT-SAS and NOCFT-MAS schemes.Numerical results show that the effective throughput of proposed NOCFT-MAS scheme performs better than that of conventional NOCFT-SAS scheme.Meanwhile,the effective throughput of the NOCFT-MAS scheme increases first and then decreases with an increase in the channel fading threshold.Based on this,the optimization problem of the channel fading threshold is further studied,the effective throughput maximization model of proposed NOCFT-MAS scheme is constructed,and an average effective throughput expression of proposed NOCFT-MAS scheme is derived.To solve the above optimization problem,the optimal instantaneous CFT-MAS(OICFT-MAS)scheme and the optimal average CFT-MAS(OICFT-MAS)scheme are proposed to maximize the instantaneous and average effective throughput of the NOCFT-MAS scheme,respectively.The results show that,in terms of the average effective throughput,the OICFTMAS scheme performs better than the OACFT-MAS scheme.Secondly,for the energy consumption problem in a multi-antenna system under the effect of limited feedback,the adaptive transmit antenna selection(ATAS)scheme is proposed,and the conventional single transmit antenna selection(STAS)scheme is considered as a baseline.The effective EE defined as the ratio of effective throughput to total power consumption is employed as the performance metric for analyzing and comparing the effective EE performance of the STAS and ATAS schemes.Simulation results show that the effective EE performance of proposed ATAS scheme is better than that of conventional STAS scheme.Meanwhile,the effective EE of proposed ATAS scheme increases first and then decreases with the increase of the channel fading threshold and the transmit power.Based on this,the jointly optimization problem of the channel fading threshold and the transmit power is further studied,the effective EE maximization model of proposed ATAS scheme is formulated,and an ergodic effective EE expression of proposed ATAS scheme is derived.To solve the above optimization problem,the ergodic effective energy efficiency optimization of ATAS(e EEEO-ATAS)scheme is proposed.The results show that the proposed e EEEO-ATAS scheme can maximize the effective EE by jointly optimizing the channel fading threshold and the transmit power.Then,for the secure transmission problem in an adaptive multiple antenna selection system under the effect of limited feedback,the effective secrecy throughput defined as the difference between the secrecy rate and the feedback rate is employed as the performance metric for analyzing and comparing the system performance of the STAS and ATAS schemes.Since the conventional STAS scheme is involved without secrecy precoding,it is also denoted as non-secrecy-precoding oriented STAS(NSP-STAS)scheme.To further improve the system performance of the ATAS scheme,the quantized secrecy precoding oriented ATAS(QSP-ATAS)scheme is proposed to optimize the precoding vector in ATAS scheme.Based on this,the optimization problem of the channel fading threshold is further studied,the effective secrecy throughput maximization model of proposed QSPATAS scheme is formulated,and the QSP-ATAS with optimal instantaneous channel fading(QSPATAS-OICF)scheme is proposed.Simulation results show that the effective secrecy throughput of proposed QSP-ATAS scheme increases first and then decreases with the increase of the channel fading threshold.Besides,the proposed QSP-ATAS-OICF scheme has the best effective secrecy throughput performance,which indicates that the proposed optimization scheme can improve the system performance of the QSP-ATAS scheme.Moreover,the effective secrecy throughput performance of proposed QSP-ATAS scheme is better than that of conventional NSP-STAS scheme.Finally,for the SRT problem in an adaptive multiple antenna selection system under the effect of limited feedback,the closed-form expressions for the outage probability and the intercept probability of both conventional STAS scheme and proposed ATAS scheme are derived,and the performance of outage probability and that of intercept probability of both two schemes are analyzed and compared.Simulation results show the existence of the tradeoff between outage probability and intercept probability of both ATAS and STAS schemes with the change of the channel fading threshold.Based on this,the optimization problem of the channel fading threshold is further studied,the sum of outage probability and intercept probability minimization model is formulated.In order to solve the above optimization problem,the sum of outage probability and intercept probability optimization of STAS(SOIO-STAS)scheme and the sum of outage probability and intercept probability optimization of ATAS(SOIO-ATAS)scheme are proposed to realize the optimization of the SRT performance of STAS and ATAS,respectively.The results show that the proposed SOIO-STAS and SOIO-ATAS schemes can minimize the sum of outage probability and intercept probability by optimizing the channel fading threshold.