Digital Cancellation of Passive Intermodulation: Method, Complexity and Measurements

This paper addresses digital cancellation of passive intermodulation (PIM) products in simultaneous transmit-receive systems, with specific emphasis on frequency-division duplexing (FDD) based LTE and 5G New Radio (NR) networks. Building on mathematical modeling of the passive intermodulation, a computationally efficient digital cancellation and associated parameter learning solutions are derived and presented. The performance of the method is analyzed through interband carrier aggregation based RF measurements at LTE/NR bands 1 and 3. The measurement results show that the proposed canceller can efficiently cancel the PIM products towards the receiver noise floor. Additionally, t he proposed canceller is shown to be of substantially lower complexity compared to the reference methods.