Behavioral Modeling of Direct-Conversion Receivers for Nonlinear Distortion Mitigation

Abstract

With the growing use of multicarrier technology in wireless communication, wideband receivers are facing increasingly severe nonlinear distortion issues. This paper focuses on the behavioral modeling of direct-conversion receivers (DCRs) for nonlinear distortion mitigation. This model accounts for arbitrary-order RF and baseband nonlinearities as well as the I/Q imbalance and can reproduce nonlinear distortion of the wideband DCR with multiple simultaneous input signals. Meanwhile, a method of model parameters estimation is put forward, which involves the inverse function method, singular value decomposition approach, and least square estimation. The experiment is performed by using a real RX chain and different types of input signals to evaluate the proposed model’s accuracy in reproducing nonlinear distortions. The experimental and simulated results suggest that the proposed model can accurately reproduce signal distortions and intermodulation products (IMDs) of DCRs with several input signals of different modulations and power levels.

Keywords

• Nonlinear distortion
• behavioral modeling
• direct-conversion receiver (DCR)
• in-phase/quadrature (I/Q) imbalance
• intermodulation distortion (IMD)