Study On Adaptive Technologies In Noncoherent Massive Antenna Systems

Ultra reliable and low latency communications(u RLLC)is the most innovative in5 G application scenarios,and its physical design is also the most challenging.As one of the breakthrough technologies of 5G,massive MIMO(multiple input multiple output)technology greatly improves the utilization of spatial dimension and effectively improves the energy efficiency.The non-coherent massive MIMO system designed by combining non-coherent technology with massive MIMO can effectively reduce the system delay and complexity,which has become a research hotspot in the u RLLC scenario.Adaptive technology is a common technology in physical layer,in which adaptive modulation can effectively improve the average transmission rate and reduce the delay;adaptive antenna selection technology can further reduce the hardware complexity and improve the system performance.In this thesis,the adaptive technology is applied to the non-coherent massive antenna system for the system design in the u RLLC scenario,and the complete adaptive modulation scheme and adaptive antenna selection scheme are constructed respectively.At the same time,the performance of the non-coherent massive antenna system in different communication environments is studied and analyzed.The main work of this thesis focuses on the following aspects(1)Aiming at the problem of system design in u RLLC scenario,adaptive modulation technology is applied to the non-coherent massive antenna system based on ED in order to improve the uplink performance of massive SIMO(single input multiple output)system.In this thesis,the optimization problem of adaptive modulation is constructed,and the system parameters related to the problem are derived and analyzed in detail,and a complete adaptive modulation scheme is designed.Simulation results show that the scheme can effectively improve the spectral efficiency of the system.(2)In order to further explore the system performance and study the performance of non-coherent system in the actual communication environment,this thesis analyzes the SER(symbol error rate)increase phenomenon caused by the fact that the number of antennas in the actual system can not tend to infinity.At the same time,considering the channel correlation in the non-coherent system,the SER of the system is derived and analyzed,and the effects of different parameters on it are discussed.In this thesis,from the perspective of minimizing SER and maximizing achievable rate,the corresponding adaptive antenna selection scheme is constructed,which further reduces the system hardware complexity and improves the system performance.The simulation results verify the effectiveness of the scheme.