Research On The Methods Of Decreasing PAPR For FBMC System

With the development of technology,the Filter banks multicarrier with Offset Quadrature Amplitude Modulation had been studied by many researchers.In multicarriers system,the problem of high peak to average power ratio was one of the key problems.Though,many solutions had been improved and researched to reduce the PAPR in OFDM system.Due to the spacial characters of the FBMC system,many existed methods were not suitable for FBMC system.Two kinds of methods were introduced in thesis.First,The partial transmission sequence had been analyzed and verfied in FBMC system.Because,the side information should be trans-mited in this method.We proposed a method which is combined with mapper solution and PTS,to lower the PAPR of FBMC system and solved the problem of side information.The main idea of the mapper is that the original datas were coded and mappered in the circle and multiply by phase factors.According to the results of simulations,mapper-PTS methods can achieve good performance in reducing PAPR.Secondly,we combined the PTS method which was already existed in OFDM system with MI AM method to reduce the PAPR.As we all know,the PTS method can get good performance in reducing the PAPR,excepting that side information should be sent,which would decreased the spectral efficiency and incresed the difficulty of recovering the original datas.So,Modified Interference Approximation Method was used in this thesis,in which we can take the advantage of the pilots in MIAM to demodulate the signals.In this situation,side infroamtion was not needed and the original datas also can be demodulated.According to the results of simulations,we can make conclusion that the PTS-MIAM method can achieve high performance in reducing the PAPR.Finally,we proposed a new pilot pattern method to lower the PAPR.Compared to the existed MIAM method,the new method can achieve high spectral efficiency.Besides,the values of pilots in the new pilot pattern were calculated to reduce the internal interferences in the first surround.The internal interferences of signals were caused in transmit,and the results of simulations,the new pilot pattern can achieve good performance in reducing the PAPR.