Detection Algorithm And Performance Analysis Of Noncoherent MIMO

In fast-fading scattering communications such as high-speed railways and low-altitude communications,the received signal phase will change rapidly.At this time,it is particularly important to be able to accurately and in real-time estimate and equalize the fast-changing channel and perform reliable communication transmission.In order to address the problems of difficult channel state information estimation and high implementation complexity of coherent MIMO communication under large Doppler shift fast-fading channel conditions,a noncoherent MIMO communication machine technology with low delay sensitivity and low implementation complexity relying only on slow-varying channel amplitude state information is being investigated.Noncoherent MIMO technology is an effective complement to coherent MIMO communication,which has advantages in reducing pilot pollution,reducing system complexity,and improving spectrum efficiency and channel utilization.In this paper,a non-coherent MIMO system using square-law nonlinear processing is designed to equate the system to a real linear model.Signal processing at the receiver side uses channel amplitude gain estimation,which ensures the link reliability while improving the spatial multiplexing gain of the system.In addition,the noncoherent MUMIMO in the Massive-MIMO cellular network regime is explored in order to further obtain greater spatial multiplexing access capability and multiple access capacity in a line-of-sight environment.The main work of this paper focuses on the following aspects:1.Square-law nonlinear processing technique is introduced.From the effect of a fastfading environment on the phase and amplitude of the channel,a noncoherent MIMO system insensitive to Doppler shift under fast-varying channel is analyzed and conventional singleuser MIMO,MU-MIMO,and Massive-MIMO are introduced.The typical Rice channel characteristics of energy detection MIMO systems in high-speed railways and low-altitude communication channels are analyzed,and the channel transmission characteristics under far-field MIMO are introduced.2.Aiming at the high reliability and large capacity communication problems of noncoherent MIMO in fast time-varying channels,an energy detection MIMO-MFSK system with better Doppler robustness in fast-fading environments is described.The system is equated to a real linear model after the square-law nonlinear treatment,and the statistical characteristics of the system under the linear model as well as the detection performance are investigated.The signal-dependent noise problem accompanying multi-antenna joint minimum Euclidean distance detection is discussed.3.The key problem of energy detecting MIMO-MFSK system is the interference caused by the nonlinear processing,which seriously affects the detection performance and the gain of spatial multiplexing.In this regard,an energy differential detection MIMO-FSK system that can eliminate nonlinear mutual interference between antennas has been adopted,and the dimension expansion problem of energy detection MIMO has been solved.To further eliminate the interference between users and antennas,the noncoherent space-time multiuser precoding of MU-MIMO in Massive-MIMO cellular systems is investigated.