DSP-based Mitigation Scheme for PA to LO Self-Coupling Impairment

This paper presents an effective mitigation scheme to alleviate signal distortion and spectral broadening caused by PA (power amplifier) to transmitter LO (local oscillator) self-coupling of a wireless SISO (single input, single-output) communication system. After constructing the equivalent baseband model of this RF impairment, important insights can be gained, from which a mitigation algorithm incorporates LS (least-squares) method for calibration and DSP-based predistortion technique for compensation is proposed. A MATLAB based IEEE 802.11g WLAN (wireless local area network) transceiver is developed to evaluate the realistic system impacts. The effectiveness of the proposed scheme and quantitative analysis on performance metrics such as ACPR (adjacent channel power ratio), EVM (error vector magnitude) and BER (bit error rate) will also be conducted through simulation.