Millimeter-Wave Full Duplex Radios

mm-Wave has emerged as an attractive high-speed wireless communication paradigm owing to the high available bandwidth at mm-wave frequencies. Full-Duplex has the potential to double the available capacity in the mm-wave bands by enabling simultaneous radio transmission and reception. While full-duplex has been extensively studied in sub-6 GHz bands, this paper exposes the unique challenges in porting this capability to mm-wave frequencies. We present mmFD, the first comprehensive system design of a mm-wave full-duplex platform. mmFD achieves large self-interference cancellation through novel designs at the antenna, analog and digital frontends. We exploit the small wavelength of mm-wave to achieve strong signal isolation between transmit and receive antennas. We further build a custom IC that achieves high-bandwidth analog cancellation at mm-wave frequencies. Finally, we present digital self-interference cancellation algorithms that address the unique hardware impairments observed at mm-wave frequencies. A detailed evaluation of mmFD demonstrates 84 dB of cancellation and 1.7x throughput gain over equivalent half-duplex systems in rich indoor settings.