Improving MIMO phase noise estimation by exploiting spatial correlations

Phase locked loops (PLL) for RF carrier synthesis often employ oscillators that insert a considerable amount of time varying phase noise into the received signal. That noise must then be removed in the digital baseband receiver. This phase noise is an indivisible superposition of noise components from receiver and transmitter. Regarding systems with multiple transmit and receive antennas (MIMO) and if multiple PLL for carrier synthesis are used each of the superposed phase noise processes per transmit and receive antenna pair can be measured at the receiver. This paper provides a new scheme for high SNR scenarios that exploits spatial correlation between these overlaying phase noise processes at the receiver in order to improve estimation and compensation of the phase noise. Therefore the Wiener filter approach is applied.