Closed-loop adaptation of a nonlinear interference suppressor for local interference in multimode transceivers

In multimode transceivers, the transmitter for one communication standard induces a large interference in the receiver for another standard, exceeding the desired signal by many orders of magnitude. To linearly suppress this interference, the receiver should have a very large linear dynamic range, resulting in excessive power consumption. An adaptive memoryless nonlinearity, which requires an adaptation signal proportional to the envelope of the received interference, can be used to strongly suppress the interference without excessive power consumption. In this paper, we propose to digitally generate the adaptation signal using a model, which describes the adaptation signal in terms of the locally available baseband interference. The model is adapted during the transceiver operation such that the power of the residual interference at the output of the nonlinearity is minimized. Simulation results show that the proposed adaptation method can strongly suppress the interference while a symbol error rate close to that of an exactly linear receiver is achieved.