A Low-Delay Self-Interference Cancellation Chip with Embeded Channel Sounding Ability

Full-duplex, which aims to simultaneously transmitting and receiving over the same band, play fundamental roles in next-generation wireless communication systems. Effective cancellation of co-band self-interference between transmitters and receivers is a major challenge of full-duplex systems. Here in this work, we present a custom self-interference cancellation chip with the ability of cancelling the analog interference from two transmitters to one receiver. It embeds additional ADC and DAC to realize channel sounding ability. Based on low-delay LVDS interface and parallel FIR filters, the total time delay of the signal reconstruction channel is below 25 ns. Experimental results of the test bench demonstrate a minimum 30 dB self-interference cancellation within 300 MHz bandwidth.