Theoretical Research And Implementation Of MIMO-OVTDM

Currently,with the increasing demand for interactive services and multimedia content delivery,research in the field of wireless communication is facing the challenge of breaking through the existing throughput.As a transmission method with high spectral efficiency,overlapping x domain multiplexing(OVXDM)technology,which provides a promising solution for bandwidth-constrained communication scenarios,has received extensive attention.The object studied in this dissertation is the application of overlapped multiplexing technology in time domain—overlapped time division multiplexing(OVTDM)technology,which establishes the coding constraint relationship between adjacent symbols through the shift and overlap of time domain waveforms,thereby obtaining coding gain.This dissertation firstly studies the basic theories of OVTDM such as channel capacity and spectral efficiency,and further discusses the expansion ideas of the technology:the design method of shaping waveform and the design scheme of digital communication transceiver for OVTDM system are proposed.Then,OVTDM is connected with Multiple Input Multiple Output(MIMO)technology.On the one hand,an equivalent implementation scheme of OVTDM system is proposed by analogy with asynchronous MIMO system model,and then the channel capacity and signal detection scheme of OVTDM are explored by referring to the relevant theoretical knowledge of MIMO;On the other hand,OVTDM technology is applied to MIMO system,and an implementation scheme of MIMO-OVTDM system is proposed.The channel capacity and signal detection of MIMO-OVTDM system are studied by using the relevant theory of MIMO.The main contributions of this dissertation are as follows:1)Taking OVTDM as the research object,two aspects are carried out:one is to discuss the theoretical issues that are controversial in the technology,starting with the more general expression of power spectral capacity,the channel capacity and spectral efficiency of OVTDM system are theoretically analyzed based on the root raised cosine roll-off pulse,and the relationship between the capacity of OVTDM and Shannon limit is further explained.The second is to expand the technology,and put forward the method of flexibly designing the shaping waveform of OVTDM system according to the spectrum template and the design scheme of digital communication transceiver without up and down sampling operation.2)At present,most researches on OVTDM system assume that each overlapping waveform is an independent parallel Gaussian channel system,ignoring the influence of the matched filter at the receiver.Therefore,based on the multiplex transmission structure of OVTDM,this dissertation proposes a practical implementation scheme of OVTDM systemcombining the shift overlap of OVTDM with the asynchronous transmission idea of MIMO,OVTDM system is realized by asynchronous MIMO equivalence.Based on the relevant theories of MIMO,the channel capacity and signal detection of OVTDM system are theoretically deduced.The simulation results show the feasibility of the OVTDM system implementation scheme.3)At present,the work on OVTDM mainly focuses on the research of single-antenna system,and the system model is relatively simple.In this dissertation,OVTDM technology is applied to multi-antenna system to significantly improve the channel capacity.A system implementation scheme combining OVTDM and multi-antenna,MIMO-OVTDM,is proposed.The channel capacity and signal detection of MIMO-OVTDM are theoretically deduced with reference to the related theory of MIMO.The simulation results verify the prospect and feasibility of applying OVTDM to MIMO system.