Research On The Reduction Of The Peak-to-average Power Radio In Massive-MIMO System

Recently, multi-input multi-output (MIMO) has been considered as one of the keytechniques in LTE/LTE-Advanced systems, since it can significantly improve the datarate, reliability, immunity to interference, and energy efficiency of the wirelesscommunication systems. Moreover, the quality of the wireless communication systemsimproves with the number of antennas. Researchers have proposed massive MIMO, tofurther improve the performances of the wireless communication systems. Comparedwith conventional MIMO systems, massive MIMO systems have much more antennas,thus, the communication quality can be significantly improved. In addition, thecomputational complexity of massive MIMO systems can be significantly reduced. Thus,massive MIMO is a promising technique for the5G wireless communication systems.For massive MIMO systems, precoding methods lead to the dynamic fluctuations ofthe transmit power at different transmit antennas, resulting in the high peak-to-averagepower ratio (PAPR) of massive MIMO signals. Practical communication systems usuallyemploy high power amplifiers to amplify the power of transmitted signals, and the linearregion of high power amplifiers is limited. Thus, high power amplifiers would clip thesignals with high PAPR, resulting in the nonlinear distortion and performancedegradation in wireless communication systems. The high PAPR is a major bottleneck formassive MIMO systems, and it prevents the practical applications of massive MIMO.This thesis mainly investigates the high PAPR problem of massive MIMO systems.Furthermore, the precoding methods are analyzed and implemented to reduce the PAPRin massive MIMO systems. Firstly, this thesis discusses the principles of massive MIMOin detail, and investigates some major technique of massive MIMO systems. Secondly,this thesis discusses the PAPR of massive MIMO systems and introduces several PAPR reduction methods. Finally, this thesis employs the precoding method to reduce the PAPRin massive MIMO systems, and its key idea is to search for one precoding with theminimum PAPR. Moreover, to verify the performances of the precoding method, weimplement the precoding method using Matlab.