Study On Technologies In Non-Coherent Massive MIMO Communication Systems Based On Constellation Design

Non-coherent massive MIMO systems do not require instantaneous channel state information(CSI)to modulation and demodulation,which can increase system capacity,reduce system latency and accommodate fast fading channel effectively.The non-coherent network,which consists of non-coherent massive MIMO systems and cellular communications,can support ultra-reliable and low latency communications(uRLLC)serving applications having high mobility,low latency and ultra-reliability.However,when users transmit data under the same time and frequency in non-coherent network,inter-user interference will be caused,which will influence system performance.Constellation design is one of the promising technologies to solve such problems and improve system performance.This paper focuses on non-coherent technologies,exploring the performance upper of non-coherent technology,solving the problem of applying it in uRLLC.Through designing each user's constellation,inter-user interference can be eliminated,which can improve system performance.Besides,this paper also studies system performance and design new non-coherent detection techniques for different communication environments.The main work consists of the following aspects:(1)Massive MIMO system model is introduced.From uRLLC perspective,it shoes that it is important to develop non-coherent technologies.Besides,the theory of non-coherent massive system is introduced and analyzed.Finally,through comparing several non-coherent massive systems,it proves the feasibility of non-coherent massive system based on energy detection in uRLLC.(2)For the bad performance problem in non-coherent massive single-input multiple-output(SIMO)system,a constellation design method based on minimizing symbol error rate(SER)is proposed.And the performance of non-coherent massive SIMO system is analyzed.Besides,the optimization algorithm can assign different optimal constellations to each user according to different signal-to-noise ratios(SNR).The simulation results show that the constellation design based on minimizing SER are suitable for different communication scenarios,can improve the system performance significantly and mitigate the adverse impacts of antenna correlation on the system effectively.(3)Regarding as the problem that non-coherent massive MIMO systems cannot communicate with multiple users simultaneously under the same time and frequency,a multi-user joint constellation based on minimizing SER is proposed.Through analyzing the performance of non-coherent massive MIMO systems and utilizing minimizing SER method,the NP-Hard problem is converted into solvable traversal problem.Finally,a suboptimal constellation is proposed to make multi-user communication possible in non-coherent massive MIMO systems.The simulation results show that by assigning orthogonal codes in different cells and multi-user joint constellations to different users reasonably,it can not only solve inter-cell user interference,but also eliminate inter-user interference.