Analysis of MIMO-OFDM system impaired by nonlinear dual-band power amplifiers

This paper presents a theoretical analysis of multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing in the presence of nonlinear dual-band power amplifiers. A two-dimensional memory polynomial model is used to describe the dual-band power amplifier. It is analytically shown that the effect of nonlinearity impairment in the transmitter can be modeled by a complex coefficient and a nonlinear additive noise. An analytical formulation is provided for symbol error rate (SER) of this system considering a frequency selective MIMO channel. The experimental results have been deployed to extract a realistic model for a dual-band amplifier. Also, the model of the linearized power amplifier has been extracted after applying digital pre-distortion (DPD). The proposed model is validated by simulation for 2 × 2 and 2 × 4 MIMO systems. The results show that the analytical model maps well onto the simulation. Also, it is shown that the DPD is able to compensate for the nonlinearity effect of the dual-band power amplifier as the SER is improved.