Research On Signal Receive Algorithm And Pulse Shaping Adaption In Gfdm Systems

Generalized Frequency Division Multiplexing?GFDM?is a non-orthogonal,digital multicarrier transmission scheme.It is a flexible block based modulation scheme capable to spread data across a two-dimensional block structure that spans over time and frequency,and by effectively applying pulse shaping to each individual subcarrier,the out-of-band radiation can be reduced.Due to the benefits of GFDM,it is a promising candidate wavaform for the fifth generation?5G?wireless communications.The thesis introduced the basic theory of GFDM,the link performance,the low complexity GFDM transceiver algorithm and the pulse shaping adaption for GFDM was studied.The main contents and innovations are as follows:1.First of all,in view of several 5G application scenarios and technical requirements,the thesis provided a comparative analysis of four modulations.Then the thesis introduced the basic theory of GFDM,including the mathematical model of GFDM transceiver,the system model of time-shift and frequency-shift offset quadrature amplitude modulation for GFDM,and the relationship between GFDM signal and inverse discrete Gabor transform?DGT?.Finally the thesis gave the simulation of the link performance for GFDM in different fading channels.2.In order to solve the high complexity and the imperfect performance of the traditional GFDM transceiver algorithm,the thesis firstly analysed serval low complexity GFDM transceiver algorithms,then based the sparsity of GFDM modulatin matrix and serial interference cancellation?SIC?scheme,an impoved GFDM receive algorithm is proposed,which can improve the performance while reducing complexity.The simulation results show that the complexity of improved GFDM receive algorithm can be significantly reduced,and compared with the traditional ZF receiver,the impoved GFDM/ZF-SIC receiver can decrease the SNR at 10^-2 by approximately 2.5dB under Rayleigh channel when the roll-off factor is equal to 0.1.3.By introducing variable pulse shaping filters,the non-orthogonality of GFDM is dismissed,as result,the influence of pulse shaping on self-interference and out-of-band radation need to be accounted.Aiming at the problem of pulse shaping adaption for GFDM system,the thesis analyses the influence of pulse shaping on self-interference and OOB,and gave a qualitative analysis result.First,for the out-of-band radation of GFDM,the thesis gave the simulation of power spectral density?PSD?for GDFM,and the influence on PSD was studied when system is configured with different parameters including subcarriers,sub-symbols and pulse shaping filters.Then the thesis analysed the probability distribution of the self-interference and the relationshape between the self-interference variance and different pulse shaping filters.Finally,the thesis concluded that the Dirichlet pulse is found to create the lowest self-interference whereas the raised cosine pulse is shown to have the lowest out-of-band radiation,and with the decreasing of filter roll off factor,the BER performance becomes to be better when using raised cosine pulse.