Researches On Pattern Division Multiple Access Applications In Next Generation Mobile Communication System

As the key technology of the fifth generation(5G)mobile communication system,non-orthogonal multiple access technology exerts great influences on user capacity,spectrum efficiency,and data rate.Compared with various non-orthogonal multiple access schemes such as non-orthogonal multiple access(NOMA),sparse code multiple access(SCMA),multi-user shared access(MUSA),pattern division multiple access(PDMA)receives less attention while it can provide better system performance theoretically.Because PDMA distinguishes users through power,code and spatial resources independently or jointly,the system performance would be influenced by many factors including power factor,spreading code,space-time code and so on.Consequently,in this thesis,we mainly investigate the influences on system error performance exerted by these factors.The thesis starts from the simulation analysis of the impacts exerted by row weight,dimension,and overloading ratio of PDMA matrix on system performance.As the essential constitution of PDMA,the PDMA matrix plays an important role for the performance.From the simulation,it shows that the bit error rate(BER)performs better as the row weight increases for the same overloading factor and dimension,as well as the dimension increases for the same overloading factor and row weight.Moreover,it shows that larger overloading factor can accommodate more users while would sacrifice the BER performance.Further,the thesis simulates and analyze the BER performance uplink single-antenna PDMA system in different signal domains.Through full search power algorithm,we analyze the impact on BER performance exerted by different power factors.Meanwhile,we achieve the BER performance of PDMA in the context of different spreading codes,which shows that the BER performance of orthogonal Gold sequences is better than that of codebook-based sparse codes.Further,based on two downlink MIMO PDMA system models,we evaluate the BER performance in the context of different space-time coding,number of antennas,and different combinations of signal domains.The simulation result show that the Quasi-Orthogonal Space Time Block Coding(Q-OSTBC)outperforms Alamouti and Vertical Bell Layered Space-Time Architecture(V-BLSTA)respectively.Finally,we summarize the main contributions and discuss the future work of PDMA.