Research On Passive Detection And Direction Finding Using Massive MIMO Receivers

Massive multiple-input multiple-output(MIMO)is a key technology in the applications of 5G and future 6G.Because of ultra-high-precision directional finding capability and spatial angle resolution,massive MIMO has attracted extensive attention and research enthusiasm from academia and industry at home and abroad.Moreover,massive MIMO is expected to be applied to multiple fields in the future,including mobile communication,Internet of things(Io T),unmanned aerial vehicle(UAV)communication,etc.In this thesis,a wide research on passive detection and direction finding using massive MIMO receivers has been made.The corresponding research contents and innovations are as follows:1)The research work on passive direction finding in conventional MIMO mainly focuses on the direction finding algorithm and performance analysis,which does not take the passive detection problem of emitter into account,i.e.inferring whether the emitter or transmitted signal exists? Thereby the effectiveness of the subsequent passive direction finding steps can be guaranteed.Inspired by the idea of radar detection,three highperformance detectors based on eigenspace were proposed: the ratio of maximum eigenvalue to minimum eigenvalue(R-Max EV-Min EV),the ratio of maximum eigenvalue to noise variance(R-Max EV-NV),and the mean of maximum eigenvalue and minimum eigenvalue(M-Max EV-Min EV).The mathematical expressions corresponding to the proposed three detectors were firstly designed,and then the detection performance was derived.Finally,the corresponding computational complexity was analyzed.Given the false alarm probability,the simulation results showed that the proposed three detectors have better performance than the conventional generalized likelihood ratio test(GLRT)and energy detection(ED)methods.2)When the number of antennas of MIMO array receivers tends to be large-scale,there exists a dilemma of high computational complexity in the conventional spatial spectrum estimation direction finding method.To address this dilemma,a low-complexity algorithm based on power iteration was proposed: Rapid power-iterative polynomial rooting(RPI-PR).The main two-step idea was as follows: the convergence of the power iteration could be accelerated through the designed initial value,so as to the complexity of the entire direction finding architecture could be significantly reduced,while its performance was maintained to be close to the Cramer-Rao lower bound(CRLB).Simulation results showed that the performance of the proposed method was not only close to the CRLB,but also its complexity was much lower than that of the classical RootMUSIC method.When the antenna tended to be large-scale,the complexity of RPI-PR algorithm is two orders of magnitude lower than that of Root-MUSIC.