A mm-Precise 60 GHz Transmitter in 40 nm CMOS for Discrete-Carrier Indoor Localization

This paper presents a multicarrier 60 GHz transmitter for distance measurement (ranging) in an indoor wireless localization system, achieving mm-precision with high update rate. The architecture comprises a baseband subcarrier generator, an upconverter, and a power amplifier. There are three key innovations, all stemming from careful hardware-algorithm co-design: 1) efficient frequency planning of the 6 GHz-wide band; 2) power-efficient multicarrier signal generation by means of digital frequency divisions exploiting the phase-based time-of-arrival ranging algorithm; and 3) PAPR reduction to enable efficient operation of the power amplifier. By implementing these key techniques, 0.7-2.7 mm precision is achieved over 5 m measured distance with 5.4 μs symbol duration. During operation, the core digital subcarrier generator generates 16 non-equidistant subcarriers from a 3 GHz input clock, while consuming an average power of 1.8 mW out of 0.9V supply. The upconverter and the power amplifier altogether consume around 127 mW. The total area of the transmitter is 1.1 mm
²
. The chip is fabricated in a 40nm general purpose CMOS process.