A Low-Power FSK/Spatial Modulation Receiver for Short-Range mm-Wave Wireless Links

Space-shift keying (SSK) or spatial modulation can provide increased energy-efficiency by using antennas/beam switching to transfer data. Such links are attractive at mm-wave due to small physical size and potential applications in slow-varying short-range channels. Low-power pulsed phased-array mm-wave TX has been demonstrated that maintains energy-efficiency while providing beam switching functionality. In this work, a two-element mm-wave FSK/SSK RX is presented that can concurrently demodulate FSK and SSK by using relative outputs of a two-element combiner to detect angle-of-incidence. A 65-nm CMOS 68 GHz 2-element RX prototype is packaged with aperture-coupled PCB antennas to demonstrate >2 Gb/s data rates while consuming <30mW across both elements. The first end-to-end CMOS SSK link using CMOS FSK-SSK TX and RX is demonstrated with 2 Gb/s data transfer across ~6 cm in a reflective channel.