An Efficient Self-Interference Cancellation Structure for Full-Duplex Radios

• Main Authors: Lin, Shih-Chang, 林世昌
• Other Authors: Chen, Sau-Gee
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/jzqf87

碩士 === 國立交通大學 === 電子研究所 === 107 === In this thesis, we propose an efficient self-interference cancellation (SIC) structure for Full-Duplex (FD) radios. We first introduce Full-Duplex (FD) Radios characteristic and state challenges in realizing FD radios. Radios suffer a strong self-interference (SI) signal from their local transmitter when operating in FD mode and, therefore, we need SIC structure in receiver part to realize FD radios. Second, we model the factors that affect SIC performance such as phase noise from transmitter oscillator and nonlinearity property from transmitter power amplifier (PA). We apply digital pre-distortion (DPD) in transmitter part to solve PA nonlinearity problem. On the other hand, structure in receiver part has to estimate SI channel and reconstruct SI signal. According to the requirement, we not only apply LMS adaptive filter to receiver part but also enhance SIC ability with the proposed low-complexity variable-step-size (VSS) LMS. We send training sequences in LMS training stage and we demodulate far-end signal. Next, we feedback result to LMS and get precise estimation in LMS tracking stage. Finally, simulation results show that 40-50dB cancellation ability is achieved in SISO FD SIC structure and 2*2 MIMO FD SIC structure