Third-order passive intermodulation distortion cancellation using a cubic Volterra filter for wireless relay systems

Abstract

Passive intermodulation distortion (PIMD) is a phenomenon in which two or more transmission signal frequencies interfere with each other due to non-linearity in passive elements of a wireless communication system and undesired signals are generated. Such intermodulation distortion increases the noise level in the receive frequency band of the wireless communication system, thereby degrading the performance of the receiver. In this paper, a PIMD mitigation scheme based on a modified cubic Volterra filter is proposed to reduce a passive intermodulation distortion level to enhance the uplink signal receive performance. The performance of the proposed approach is evaluated by applying it to the data sampled at a repeater for the long term evolution (LTE) system. The proposed approach demonstrates a notable reduction of PIMD in the receive band. The conventional least mean square (LMS) approach is considered in this study for the purpose of comparison.