A real-time TX-RX leakage cancellation in RF transceiver

The growing demand for integration level of RF transceiver leads to the deterioration of isolation between transmission (TX) and receiving (RX) channel. The out-of-band nonlinear component of TX is likely to hit RX band in FDD scene and deteriorate receiver’s sensitivity. The traditional studies of leakage cancellation method focus on the leak point of RF poweramplifier. However, as the widespread using of Digital PreDistortion (DPD) algorithm in transceiver, the out-of-band predistortion component in TX channel will interfere $R X$ channel if the isolation level between TX pin and RX pin is insufficient. This paper presents a real-time digital cancellation algorithm for TXRX leakage. Compared to other solutions in the industry, the proposed algorithm introduces frequency-domain process and linkage design with AGC, which can maintain good performance in large blocking scenario, and is well-balanced between algorithm complexity and performance.