Compensation of I/Q imbalance in M-QAM tranceiver with multi-antennas

An approach to the compensation of I/Q imbalance is discussed in this paper. A method based on the least squares (LS) is proposed. Although digital orthogonal demodulation provides an efficient means for system and circuit designers to avoid the effect which is caused by local oscillation (LO), to sample broadband signal with high-rate analog-to-digital (ADC) suffers from high cost and increases difficulty of the implement of FPGA. This paper presents a rigorous analytical model for analyzing the effects of local oscillator output imperfection of in-phase/quadrature (1/Q) imbalance on M-ary quadrature amplitude modulation (M-QAM) transceiver performance. Then a method of compensation of the 1/Q imbalance is proposed according to the model.