A Circuit Technique for Blocker-Induced Modulated Spur Cancellation in 4G LTE Carrier Aggregation Transceivers

Abstract

In this paper, we propose a novel mixed-signal cancellation circuit for LTE carrier aggregation receivers targeting modulated spur interference. This circuit senses interference via an auxiliary analog path, and generates a reference signal for the adaptive digital cancellation. To evaluate the performance of the proposed technique, a demonstrator, realized in 28 nm LP CMOS, is shown with a cancellation of over 20dB and low impact on the main path while consuming 14.3 mW. Measurement results show that the receiver's noise figure is restored to a value within 0.1 dB of the reference value.