| In contrast to the traditional Orthogonal Frequency Division Multiplexing(OFDM)system,the Filter Bank Multicarrier(FBMC)system uses the prototype Filter Bank with better performance as the modulator of the whole system,and has the advantages of better anti-multipath channel ability,less out-of-band leakage and higher spectral efficiency without using cyclic prefixes.Therefore,it has attracted extensive attention from academia and industry,and is considered to be able to replace OFDM system in mobile communication scene in the future.As an important component of FBMC system,the design and implementation method of prototype filter has always been a key research field in FBMC system.Because the prototype filter can have a direct impact on the performance and implementation complexity of FBMC system,it is necessary to optimize the design of FBMC system prototype filter to meet more diversified communication needs in the future.Based on the existing research,this paper studies the impact of the prototype filter on the system performance,transmission efficiency and implementation complexity,and puts forward the corresponding design scheme.The specific research work is as follows:In order to improve the SINR performance of the FBMC system,this paper derives the theoretical expression of the Signal to Interference plus Noise Ratio(SINR)of the FBMC system,and establishes the objective function of maximizing the SINR of the FBMC system.A prototype filter optimization problem with ripple and stopband attenuation performance as constraints and the prototype filter coefficients are solved.The simulation results show that,compared with the classic PHYDYAS filter,the prototype filter designed in this paper has better stop-band attenuation performance on the premise of obtaining approximate and better SINR and Symbol Error Rate(SER).Aiming at the problem of low time-domain transmission efficiency of FBMC system,this paper proposes to truncate the time-domain transmission signal of FBMC system to improve the time-domain transmission efficiency,and at the receiving end,the truncated part is zero-padded to restore the standard-length FBMC-OQAM received signal.Since time-domain truncation greatly changes the signal integrity,in order to take into account the system SINR performance,the effect of time-domain truncation is eliminated by optimizing the prototype filter.The simulation results show that,compared with the classic PHYDYAS filter,the prototype filter designed in this paper can improve the transmission efficiency in the system time domain on the premise of obtaining approximate and better SINR and SER.Aiming at the high complexity of FBMC system implementation,this paper proposes to design a low-complexity prototype filter using the Interpolated Finite Impulse Response(IFIR)technique of serial optimization design,and apply it to the FBMC system.The simulation results show that,compared with the classic PHYDYAS filter,the prototype filter designed in this paper reduces the complexity of the system implementation on the premise of obtaining approximate SINR and bit error rate.In conclusion,this paper designs the prototype filter according to the optimization,which can achieve better transmission performance and implementation complexity. |
