RF & Microwave Technology

Breakthrough Integrated Chip Circulator for Full Duplex Communication

Columbia University engineers in the Columbia high-Speed and Mm-wave IC (CoSMIC) Lab have created a receiver integrated circuit (IC) intended for full-duplex wireless - an exciting new wireless communication paradigm where the transmitter and the receiver operate at the same time and at the same frequency. Since frequency and temporal resources are used to the fullest extent possible, full duplex wireless potentially doubles network capacity in the physical layer, while offering many other benefits at the network layer. The challenge associated with full-duplex wireless is the high transmitter self-interference, or echo, at the receiver input. This self-interference can be as high as a billion times more powerful than the desired signal to be received. This research builds on work on an integrated circulator that allows the transmitter and the receiver to share the same antenna, while providing isolation between the two, allowing for compact-form-factor full duplex radios. In addition, the team developed analog baseband and digital self-interference cancellation techniques that suppress the echo to the tune of nearly one part per billion. The aspects make this the first full-duplex receiver IC reported that achieves the levels of echo cancellation required for full-duplex wireless.