Research On Mutilevel Continuous Polarization Modulation Scheme In Wireless Communicatuon

Spectrum in wireless communication is a kind of rare resource. To improve the spectrum efficiency, Polarization Modulation (PM) uses the State of Polarization as the information-bearing parameter. It exploits the carrier signal with an additional degree of freedom without impacting the other parameters such as frequency, phase and amplitude. What’s more, PM also has a flexible constellation structure. Therefore, PM is considered as a promising method to improve the spectrum efficiency and is well studied. However, in traditional Multilevel Polarization Modulation (MPM) the switches among the discrete Sates of Polarization (SOPs) lead to the discontinuity of signal waveforms, which will broaden the bandwidth and decrease the bandwidth efficiency consequently. To overcome this problem, a Multilevel Continuous Polarization Modulation (MCPM) scheme with continuous SOPs is proposed in our research.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)".This work aims to improve the spectrum efficiency through the Multilevel Continuous Polarization Modulation scheme with continuous SOPs. Our work focuses on how to design efficient modulation and demodulation schemes. Furthermore, the impact to the MCPM caused by the Polarization Dependent Loss (PDL) effect in wireless depolarized channel is analyzed, and the pre-compensation algorithm is developed as well. Following is the research work.Firstly, the work summaries the theory and technologies of polarization signal. During the analysis, the feasibility to achieve continuous SOP is demonstrated based on the current foundation. Then, the existing researches on PM are analyzed and the PDL effect of wireless depolarized channel is also analyzed as follow.Secondly, to alleviate the problems caused by the abrupt switches among discrete SOPs which will decrease the bandwidth efficiency greatly, the MCPM scheme is proposed with continuous SOPs to produce continuous signal waveforms. The signal is modulated and demodulated at the transmitter and receiver. The performance of MCPM is analyzed under additive white Gaussian noise (AWGN) channel. The simulation result shows that the spectrum efficiency and symbol error rate are improved in the proposed scheme.Thirdly, the PDL impairment of the wireless depolarized channel model is analyzed and an optimal pre-compensation algorithm based on the maximum polarized angle is presented to mitigate this impairment. Finally, the theory and simulation analysis show that the bandwidth efficiency and symbol error rate of MCPM are improved when the pre-compensation algorithm is proposed under the depolarized channel.