FlexRadio: Fully Flexible Radios

For a long time the capability of wireless devices to be configured either as a transmitter or a receiver at a time was the norm. The invention of full duplex shattered this norm. Theoretically, given N-RF chains with full-duplex capability, if each one can be configured as a receiver or a transmitter, we should be able to generate N transmission modes. Can a system capable of utilizing all possible transmission modes exist? Is this achieved flexibility critical to enhance the wirless communication system? We show that the answer to these questions is yes. This paper presents the design and implementation of FlexRadio, the first system enabling flexible RF resource allocation. This paper presents a novel RF cancellation technique that minimizes the number of canecalltion elements needed to realize FlexRadio. We implement FlexRadio on the NI PXIe 1082 platform using XCVR2450 radio front-ends. Our FlexRadio implementation shows a median gain of 2X over MIMO and fixed full-duplex radios having the same number of RF chains.