Research On The Performance Of Mode Division Multiplexing System Based On Polar Coded Modulation

As the core part of the backbone telecommunication system,the technologies of optical-fiber communication systems to improve the transmission capacity are becoming more and more mature.However,the systems based on single-mode fiber are approaching their theoretical capacity limits,so the mode-division multiplexing(MDM)technology based on few-mode fiber and multi-mode fiber has attracted extensive attention.The MDM system uses a set of orthogonal modes to transmit independent and parallel data streams,so ideally the capacity of the system is proportional to the number of modes.Although long-distance transmission inevitably leads to coupling between different modes in practical application,which further leads to crosstalk and interference,the researches have shown that Multiple Input Multiple Output(MIMO)digital signal processing(DSP)technology can separate parallel data streams and improve the performance of the MDM system.Polar Codes is the only emerging channel coding scheme which is theoretically proven to reach the Shannon limit and have low coding and decoding complexity.The parallel antenna partition based Polar Coded MIMO system based on the generalized polarization idea is the joint optimization of polar coding,signal modulation and MIMO transmission and researches also show that bit interleavers is the key to improve system performance.The paper studies the bit interleaving scheme based on the parallel antenna partition based Polar Coded MIMO system,and introduces the generalized polarization idea into the MDM system to further improve the performance.The main work contents are as follows:(1)Calculate the statistical properties of the bit synthesized channels,propose two interleaving scheme and simulate and analyze their performance in MATLAB.The results show that the proposed interleavers can nearly achieve the performance of random interleaver with 16 QAM modulation,even better by about 0.3d B when the code rate is 0.5.Meantime,the system hardware complexity is reduced.(2)Apply the generalized polarization idea to the MDM system and establish the fiber channel.Simulate and analyze the performance and complexity of the different MIMO detection algorithms.The simulation results show that the Polar Coded MDM system can achieve a lower block error rate in a small range of bit signal-to-noise ratio,about 10 d B improvement than the uncoded MDM system.And IRS-MST detection algorithm can achieve ML performance while the complexity is about 4.5 times smaller than ML detection,and about 1.2 times smaller than IRS detection algorithm.