Antenna/RF Design and Analog Self Interference Cancellation

The main obstacle to full-duplex radios is self-interference (SI). To overcome SI, researchers have proposed several analog and digital domain self-interference cancellation (SIC) techniques. Digital cancellation has the following limitations: (1) It is only possible if the SI is sufficiently removed in the analog domain to fall within the dynamic range of an analog-to-digital converter (ADC). (2) It cannot mitigate the transmitter noise. Thus, analog cancellation plays an important role in a SIC scenario. This chapter provides an overview of current research activities on the analog cancellation scheme. Analog cancellation can be categorized into two classes—passive and active. In the passive analog cancellation, an RF component suppresses the SI. This can be implemented using a circulator or antenna separation. Leakages are cancelled by the active analog cancellation, which is based on a channel estimation of …