The OVTDM Decoding Algorithm Based On Message Passing

Currently,the fifth generation mobile communication technology is officially commercial in China,and its peak transmission rate has reached lOGbps,which puts forward higher requirements for the research of the next generation mobile communication technology.Overlapped Time Domain Multiplexing(OVTDM)system has a non-orthogonal transmission method.It artificially introduces inter-symbol interference through waveform overlapping,and thus achieves high transmission rate.It is expected to be an important research direction of the next generation mobile communication technology.However,due to the introduction of inter-symbol interference,the computational complexity of the OVTDM system increases exponentially with the increase of overlapped multiplexing coefficient,which limits the application of the OVTDM system.Therefore,it is of great significance to study low-complexity and high-performance OVTDM system detection algorithms.In order to study the low-complexity OVTDM system detection algorithm,this paper deduces the relationship between the transmitted symbol sequence and the received signal,then constructs a factor graph model correlating the two.Then,this paper applies the idea of message passing to the detection process of OVTDM system based on the factor graph model,and proposes two OVTDM system detection algorithms based on message passing.These two detection algorithms utilize the continuous iterative updating of information between nodes to realize signal detection.Then,this paper analyzes the computational complexity of the two detection algorithms,and verifies the performance of the two detection algorithms through simulation.The simulation results show that these two detection algorithms can greatly reduce the computational complexity while ensuring the detection performance,which shows a good application prospect.Finally,this paper studies the OVTDM system under the multipath fading channel,and constructs the OVTDM system model under the fading channel.Then,this paper applies the two detection algorithms proposed before to the fading channel environment,and compares their performance by simulation.The simulation results show that the two detection algorithms proposed in this paper have great advantages compared with the Viterbi algorithm in specific application scenarios.