| The increasing energy consumption in wireless communication severely pushes down the industry profit and results in significant pressure to the environmental protection. The power amplifier is a main factor to this problem. It consumes high energy consumption, but has very low energy efficiency because of the strict requirement of operating at linear region. To improve the PA energy efficiency, a significant feature that the Polarization State (PS) in wireless communication are not impacted by PA nonlinear distortion has been explored. By introducing PS as the information-bearing parameter, the PA can be allowed to operate at nonlinear region to acquire high energy efficiency.The research work is sponsored by "Chinese National Nature Science Foundation:Research on power amplifier energy efficiency based on cognitive and polarization signal processing (61271177)".The dissertation is focused on the PA energy efficiency improvement through polarization modulation (PM). Firstly, the methods and technologies of bearing information by PS on the traditional transceiver are investigated; the impact to the PM caused by the polarization dependent loss effect of the wireless depolarized channel is analyzed, and the compensation algorithm is developed. Secondly, to further improve the PA energy efficiency, the polarization-amplitude-phase modulation (PAPM) which combines polarization and existing amplitude/phase modulation is proposed. For the PA energy efficiency realized by PAPM is dependent on the output back value and the concrete modulation parameters, a constrained optimization problem is formulated. Through the simulation, the optimum solutions to the problem are presented. Thirdly, in the multi-carrier PAPM scene, the research on the energy efficiency improvement of the downlink PA is carried. Considering the impairment to PAPM caused by the PMD effect, the PA energy efficiency optimization model of the base station is established and a low complexity carrier-power allocation algorithm is proposed to the make improve the PA energy efficiency.The main research work and achievements of this thesis are as follows:(1) The related theory and techniques of the PA nonlinear effect research and the polarization signal processing are analyzed; then, the nonlinear distortion immunity property of PS is demonstrated.(2) The PM is proposed to improve the PA energy efficiency. Firstly, the PM and the corresponding demodulation scheme are designed on the traditional transceiver, also the symbol error rate and the PA energy efficiency of PM under AWGN (additive white Gaussian noise) channel are analyzed; then, the polarization dependent loss impairment of the wireless depolarized channel to PM is analyzed, and the corresponding optimal pre-compensation algorithm is presented to mitigate such impairment; finally, the symbol error rate and PA energy efficiency of PM under the depolarized channel are analyzed.(3) The PAPM is proposed to improve the PA energy efficiency. Firstly, the PAPM and the corresponding demodulation scheme are designed; then, the PA energy efficiency optimization model based on PAPM is established and the optimal PAPM is presented to make the PA energy efficiency optimal; finally, the symbol error rate and PA energy efficiency of the optimal PAPM under the depolarized channel are analyzed.(4) To improve the downlink PA energy efficiency in the multi-carrier PAPM scene, the PA energy efficiency optimization model is established; then, the carrier-power allocation algorithm based on the population-based evolutionary optimization and the greedy optimization algorithm is presented to make the downlink PA energy efficiency optimal; finally, the PA energy efficiency acquired by the proposed carrier-power allocation algorithm under the channel with the polarization mode dispersion effect are analyzed. |
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