Research On Phase Noise Cancellation Based On Polarization Signal Processingfor OFDM Systems

In orthogonal frequency division multiplexing(OFDM)systems,phase noise introduced by oscillators can cause severe performance loss.The effect of phase noise is characterized by common phase error(CPE)and inter-carrier interference(ICI)leading to bit error rate(BER)of OFDM systems and other performance degradation.Moreover,phase noise also leads to ergodic capacity of massive MIMO-OFDM systems degradation.Polarization state,which is a property of signal,is insensitive to phase noise.Therefore,we propose a series of schemes to cancel the effect of phase noise in OFDM and massive MIMO-OFDM systems by exploiting the polarization signal processing technology.The thesis focuses on canceling the effect of phase noise in polarized domain for OFDM and massive MIMO-OFDM systems.We propose the polarization signal processing technology to cancel the effect of phase noise in OFDM systems and massive MIMO-OFDM uplink,including CPE and ICI.According to the difference betweenthe phase noise linewidth and the subcarrier bandwidth,and the number of antennas in OFDM systems,the research is divided into three parts.The first part is the CPE cancellation based on the polarization modulation and differential polarization modulation schemes for OFDM systems.Secondly,a phase noise cancellation based on orthogonal polarization scheme including CPE and ICI cancellation,is proposed.The third part focuses on the phase noise cancellation scheme based on polarization modulation for massive MIMO-OFDM systems in the large-scale antennas scenarios.The main research work and achievements of this thesis are as follows:(1)The related theory and techniques of phase noise in OFDM and massive MIMO-OFDM systems,and the polarization signal processing in wireless communication are analyzed and reviewed.On this basis,the advantages and challenges of exploiting the polarization signal processing technology to cancel phase noise are discussed,which is the foundation of phase noise cancellation for OFDM and massive MIMO-OFDM systems in this thesis.(2)To solve the the BER performance degradation problem caused by CPE,the polarization modulation based CPE cancealltion(PMCC)scheme for OFDM systems is proposed.Firstly,the polarization modulation and demodulation schemes are designed in OFDM systems.Then,the CPE cancellation performance of the PMCC scheme is analyzed in the AWGN and PDL channel.Moreover,the differential polarization modulation based CPE cancealltion(DPMCC)is proposed to suppress the impact of polarization-dependent loss(PDL)effect caused by the wireless depolarization channel.Finally,the simulation results show that the BER performance of the PMCC and DPMCC schemes can be increased by 5-6dB.(3)To solve the the BER performance degradation problem caused by CPE and ICI,the orth-ogonal polarization based phase noise cancellation(OP-PNSC)scheme for OFDM systems is proposed.Firstly,the orthogonal transmission and reception schemes based on orthogonal polarization are designed in OFDM systems.And then the cancellation performance of CPE and ICI in the AWGN channel is analyzed.Also,the pahse noise cancellation performance is analyzed under the PDL channel.Thus,a PDL pre-compensation scheme is proposed to reduce the PDL effect for the OP-PNSC scheme.Finally,the simulation results show that the OP-PNSC scheme can effectively improve the BER performance of OFDM system under the different channels.(4)To solve the ergodic capacity performance degradation problem caused by phase noise,the polarization modulation based phase noise cancellation scheme for massive MIMO-OFDM systems is proposed.Firslty,the phase noise cancellation model based on polarization modulation is built,according to the phase noise insensitivity property of polarization state.Based on this model,the polarization modulation and demodulation schemes are designed for the massive MIMO-OFDM uplink.Then,by exploiting the zero-forcing detector and as the number of antennas at the base station is tend to infinite,the ICI power asymptotically tends to 0,and the transformed additive noise is AWGN and the distribution of the transformed additive noise is not changed.On these basises,we demonstrate that phase noise can be asymptotically cancelled as the number of antennas at the base station is very lager,and the phase noise cancellation performance of the proposed scheme is further derived.Finally,the simulation results show that the ergodicity capacity of the proposed scheme is twice as much as that of the traditional single user systems,and is better than the traditional two user systems in the case of large phase noise power and large SNR regime.