Research On Filter Bank OFDM System And Channel Estimation Technology

OFDM technology originated in the 1970s.After decades of research and development,it has been widely used.OFDM has advantages of high spectrum efficiency,strong anti-interference ability and low transceiver complexity.While it also has problems of serious out-of-band leakage and high demand for synchronization,these shortcomings make it difficult to meet the need for the new scene in the future.The Filter Bank OFDM(FB-OFDM)technology has advantages of small out-of-band leakage,flexible waveform function and support asynchronous transmission between carriers and so on.Therefore,the study of FB-OFDM technology is of great significance.The characteristics of wireless channel and the simulation model of the channel are studied in the first place.And on this basis,FB-OFDM link simulation platform is established on MATLAB.Secondly,the principle and system framework of FB-OFDM is elaborated,including the realization of polyphase filter,the design of wave function and the analysis of frame structure.The design of waveform function is emphasized in this paper.The waveform function designed has good time-frequency domain characteristics,suppressing out-of-band leakage effectively.The advantages of FB-OFDM is researched compared with OFDM.The simulation results show that the FB-OFDM is insensitive to the asynchronous interference,can better realize the asynchronous transmission.It will meet the needs of the users in the new situation and is suitable for future communication systems.Finally,pilot-based channel estimation algorithm in FB-OFDM is studied.Several classical channel estimation algorithm and interpolation algorithm are analyzed.Aiming at disadvantages of fixed pilot algorithm in FB-OFDM,an adaptive algorithm for adjusting pilot density under certain circumstances is proposed in this paper.The algorithm can adaptively select the pilot density under the condition of satisfying the performance requirements of the system,reducing the pilot overhead.The simulation curves show that when the channel changes continuously,the algorithm can adjust the pilot interval adaptively according to the change of the environment.The pilot density coincides with the current channel conditions,improving the channel utilization efficiency effectively.