Research On Algorithm Of Reducing Peak To Average Power Ratio In MIMO-OFDM System

With the development of the modern network demand, information transmission requirements of high speed,high quality, efficient use of spectrum resources,greatly improve the spectrum efficiency. OFDM technology has many advantages, such as strong anti-interference ability, higher bandwidth efficiency. Combined with the characteristics of MIMO technology, MIMO-OFDM system is formed to some extent to meet the information transfer the above requirements. MIMO-OFDM integrated MIMO and OFDM two kinds of technology advantage. However, many sub carrier signals via the IFFT module overlay operations after initial phase of the same or similar, resulting in MIMO-OFHigh peak value of OFDM signal in DM system. High quality of communication PAPR would be detrimental to the system, the PAPR problem is particularly important in the uplink, because the power amplifier efficiency is limited by the mobile terminal battery power is limited.First of all, the two technologies of MIMO and OFDM are expounded, the development of.MIMO technology and OFDM technology,and the advantages and disadvantages,the advantages and disadvantages of the integration of the two technologies, as well as the challenges faced by technology;Secondly, on the PAPR of MIMO-OFDM generation are introduced. Including the PAPR of the definition, the distribution of OFDM signal in MIMO-OFDM system, and the relationship between the PAPR and multi sampling;Thirdly, the existing methods to reduce the peak to average ratio are studied, including clipping filtering technology and partial transmission sequence Technology (PTS). The improved algorithm is proposed and verified by theoretical simulation;Finally, the system modules were added to the pulse shaping module and compression expansion module are studied. The pulse shaping is between the sub carrier control between OFDM block without interference of the modulation signal orthogonality technology;compression and expansion is to reduce the OFDM signal PAPR is a low complexity method,through compression and expansion to restore the original the data transform can effectively reduce the nonlinear distortion. The companding transform of OFDM signal, the signal after the approximate target distribution of lower PAPR, so as to improve the performance of PAPR. Finally, the system of PAPR and BER performance through the simulation.