Low-Complexity Fully-Digital Phase Noise Suppression for Millimeter-Wave Systems

Abstract

Phase noise (PN) estimation and compensation is needed for millimeter-wave (mmWave) communication systems to achieve high data rates. Conventional approaches for PN suppression suffer from high computational complexity. To overcome this, we present a low-complexity fully-digital PN suppression for mmWave systems. The key ideas are to exploit the coherence bandwidth of a mmWave system and an approximation of the PN spectrum, based on its N p dominant components. Utilizing these features, the joint estimation problem of PN and channel can be reformulated into a system with the same number of equations and unknowns, which enables low-complexity PN suppression by using a linear minimum mean square error (LMMSE) estimator. Furthermore, we propose a method to reduce the hardware cost of the LMMSE estimator by using a B-bit signal-to-noise ratio (SNR) quantization, which has a very low complexity of O(N p 2 + NN p ), where N is the number of subcarriers in an OFDM symbol. As a proof-of-concept, a low-cost VLSI architecture is presented to realize the proposed method. The proposed architecture in 28 nm CMOS (post-synthesis) results in an area cost of 258 K gate count and power consumption of 19.3 mW at 250 MHz clock rate.