Experimental Evaluation of an Adaptive Nonlinear Interference Suppressor for Multimode Transceivers

In multimode transceivers, the transmitter for one communication standard may induce a strong interference in the receiver for another standard. Using linear filtering techniques to suppress this interference requires a receiver with a very large dynamic range, leading to an excessive power consumption. A much more power efficient approach suppresses the interference using an adaptive nonlinear interference suppressor (NIS). In previous work an ideal model was used to derive an adaptation method and study the receiver performance afforded by the NIS. In this paper, we present experimental results of a receiver that uses an implementation of the NIS, fabricated in 140 nm complementary metal-oxide-semiconductor technology. Main imperfections that limit the NIS performance are identified, simple models are developed that explain the experimental results, and for the key imperfections, low-complexity digital compensation and calibration methods are proposed. These digital methods permit the use of lower-performance analogue circuits, thus further reducing the transceiver cost and power consumption. The experimental results show that the NIS can achieve a substantial interference suppression at attractive complexity and power dissipation.