Nonlinear MIMO impulse responses determination using pseudo random sequences, and nonlinear compensation

Abstract

This paper shows how to estimate an extended polynomial matrix description of a non-linear MIMO system. Both linear and non-linear impulse responses are obtained by transmitting pseudo random binary sequence (PRBS) test-patterns and can be easily separated thanks to the shift-and-add property of PRBS. Further on, a method to equalize such nonlinear systems based on this extended polynomial matrix and the result is compared with a linear zero-forcing equalizer for different channel impairments and in a VPI simulation. This proves the presented approach is suited to cancel self-phase modulation in coherent optical communication systems.