Joint compensation of I/Q impairments, power amplifier nonlinearity and crosstalk in MIMO transmitters using two-box model

A novel two-box model for joint compensation of nonlinear distortion introduced from both in-phase/quadrature modulator and power amplifier is proposed for 4G multiple input multiple output (MIMO) transmitters. Compensation of nonlinear distortion is accomplished in two phases, where phases are identified separately. It is shown that complexity of the digital predistortion is reduced. The performance of the proposed model is evaluated through simulations and measurements, in terms of ACPR, EVM and NMSE improvements using two 3 MHz LTE signals and two WCDMA signals, respectively.