Research On Technology Of Universal Filtered Multicarrier System

The fifth generation mobile communication system(5G)is the next generation mobile communication system for ultra-wideband spectrum,large-scale machine-to-machine communication and high-speed mobility communication.Compared with the 4G communication system,the 5G communication system has the distinctive features,it can meet the service needs of the low latency and high reliable transmission performance,such as Tactile Internet,spectrum sharing,machine communication(MTC)and Internet of Things.Currently,the Universal Filtered Multicarrier(UFMC)is considered as an 5G popular candidate waveform that can replace the Orthogonal Frequency-Division Multiplexing(OFDM),due to its small out-band leakage and high time-frequency efficiency.This research focuses on the non-orthogonal multi-carrier transmission technology,specially on the UFMC waveform technology,the main contents are as follows:(1)Introduce the 4G mainstream waveform technology–OFDM and 5G candidate waveforms of Filter Bank Multi-Carrier(FBMC)and Generalized Frequency Division Multiplexing(GFDM),then studied the basic model of UFMC technology and its realization principle,including transmitter signal generation,receiver signal processing and filter design,and compared the performance among CP-OFDM,FBMC and UFMC as well,from power spectral density,time-frequency efficiency and complexity.Finally,the application of UFMC waveform is analyzed.(2)Describes the wireless channel fading characteristics,elaborates on the causes of each fading and the corresponding characterization parameters,and discusses and simulates the channel models involved in this paper.The reasons of timing offset and carrier frequency offset are analyzed,and the single-user UFMC time-frequency offset model is established.The influence of timing offset and carrier frequency offset on UFMC waveform is theoretically analyzed by mathematical derivation.Finally,the graph of the overall system signal to interference ratio with the timing shift when different carrier frequency offset exists is simulated.(3)An ideal and time-varying channel model with carrier frequency offset is established to study the combined effect of channel variation and carrier frequency offset on UFMC.The signal-to-interference ratio of UFMC and OFDM signals when carrier frequency offset exists is analyzed and simulated.And the performance of UFMC bit error rate for a particular channel COST207 is carried out as well.The results shows that compared with OFDM system,UFMC system has better anti-frequency offset performance under time-varying channel.(4)A UFMC time-frequency synchronization algorithm based on ZC prefix code is designed.The synchronization algorithm generates ZC repetitive sequences in the time domain,and then constructs a new timing metric function and a joint decision criterion for the correlation peak of the metric function,which improves the performance of timing acquisition performance and integer multiple frequency offset estimation.The simulation results show that the proposed algorithm has high precision performance of timing capture and frequency offset estimation,and robust to Doppler time-varying fading.Finally,the UFMC channel estimation algorithm is studied.The channel estimation based on LS and MMSE is theoretically deduced.The mean square error and bit error rate performance of the two estimation methods are compared under COST207 channel.In summary,the research and conclusions in this paper can be a reference for the design of 5G wireless transmission technology under the high-speed mobile channel.