Research On Modulation Technology Based On High Efficiency Power Amplifier

Radio Frequency(RF)Power Amplifiers(PA)is the most important component in the back end of a transmitter in a wireless communication system.It is also the most energy-consuming device in wireless communication systems,and its energy efficiency largely determines the energy efficiency of the entire communication system.Therefore,under the background of promoting energy conservation and protecting the environment,it is of great theoretical and practical significance to study the signal modulation technology based on high efficiency power amplifier.This paper first analyzes the studing background and significance,and introduces the research status of imoving the efficiency of PA.Based on the modulation technology and characteristics of the PA,two signal modulation schemes based on high efficiency PA are studied.Both signal modulation schemes increase the efficiency of the power amplifier,thereby reducing the power consumption of the entire communication system.The detailed descriptions of this article are as follows.Chapter 1 expounds the background and importance of the research,analyzes the research status of improving the efficiency of PA,briefly introduces the RF PA,and gives the main research contents and structure of this paper.Chapter 2 studies the signal modulation technology based on switching mode power amplifiersignal(SMPA).This chapter first introduces the principle of quadrature and Pulse Width Modulation(PWM).By combining the two modulation methods,the inputs of the PA are square wave signals,so that we can improve energy efficiency of the PA by using a higher efficiency switch type PA.This chapter gives a system block diagram of this signal modulation scheme,and simulates the signal spectrum characteristics and bit error rate(BER)performance.Chapter 3 studies the Phase Modulation on the Hypersphere(PMH)technology that can be applied to MIMO systems.This chapter first gives a system block diagram of single-RF MIMO system and signal characteristics of PMH.The signal constellation of the PMH is located on the multi-dimensional hypersphere,so the input signal of the central RF PA is constant envelope.According to characteristics of the PA,low Peak-to-Average Power Ratio(PAPR)of inputs can ensure higher efficiency.This chapter presents a codebook generation algorithm based on K-means clustering algorithm and a constellation mapping algorithm based on Gray code.This chapter studies several common MIMO signal detection schemes and compared their performance.Chapter 4 proposes two improved schemes for the problem of high complexity of Maximum Likelihood(ML)detection algorithm in PMH system.Among them,the two-stage codebook and its iterative detection algorithm can reduce the computational complexity,but have a certain performance loss and are demanding on channel conditions.The KD-Tree-based signal detection scheme can reduce the amount of calculation without losing performance,but only requires the channel to be stable.The principle of the two algorithms is introduced in detail,and the computational complexity of the two algorithms is analyzed.The performance and calculation amount are compared with the ML algorithm by simulation.Chapter 5 gives a comprehensive summary of the paper,explains the main contributions and innovations of this paper,and gives suggestions for future work.