Adaptive Front Control Module In The Feed-forward Power Amplifier Design And Research

In the modern wireless communication system, spectrum resources are becoming increasingly scarce for the sharp increase of subscribers. To conserve spectrum resources and improve spectrum efficiency, information transmission technology towards to the multi-carrier, large capacity, high-speed and high peak-to-average ratio direction. These call a higher linearity of devices in communication system, power amplifier as the main components of wireless communication system gives rise to a major source of nonlinear distortion, so the linear technology is becoming a current hot spot. The adaptive feedforward linearization technology in this dissertation discussed is a mainstream of linear technology.As the feedforward technology with the characteristics of high linearity and wide frequency band which can be used well in the current communication system. At present, overseas have done much work and mass production in this area, some domestic universities and enterprises have also done a lot of work but have not realized the final product. this dissertation will do some further research on the feedforward amplifier based on previous studies.The first chapter of this paper focuses on the research background, significance and necessity of the research topic. The second chapter describes the nonlinear characteristics of amplifiers, including harmonic distortion, intermodulation distortion and AM-PM, AM-AM distortion etc., also introduced the nonlinear indicators of power amplifier, such as the 1dB compression point, third-order intermodulation coefficient, the output third order intercept point, adjacent channel power rejection ratio and noise figure. The third chapter describes the commonly used international linearization technology, mainly discusses the application of adaptive technology in adaptive feedforward system, including the minimum power detection technology, signal correlation detection technology and pilot signal detection technology. The fourth chapter mainly analyzes the mathematical model of feed-forward amplifier, optimization of abroad adaptive algorithm, and propose a new method of adaptive signal detection and optimum program with the requirement of the practical system, at last give the MATLAB simulation of adaptive algorithm. The fifth chapter introduces the design and implementation of software and hardware of the adaptive feedforward power amplifier control module, and gives the test result of the adaptive control module。.The adaptive control module as an important component of the adaptive feedforward amplifier system plays an important role for the real-time adjustment of linearity. In practice, this design need to constantly adjust the algorithm according to hardware to facilitate the system more robust and real-time.