Estimation of Frequency Unsynchronized Millimeter-wave Channels

We propose an algorithm for mmWave channel estimation in the presence of a non-negligible carrier frequency offset (CFO) impairment. The algorithm exploits inherent sparsity of the mmWave channel in the angle of departure (AoD) and arrival (AoA) domain, employs sparse channel sensing protocol, and performs blind CFO compensation and estimation of channel paths in the angular domain. The simulation tests show that the proposed algorithm considerably outperforms the conventional orthogonal matching pursuit (OMP)-based mmWave channel estimation algorithm under different CFO and signal-to-noise ratio (SNR) regimes. Aside from the mmWave channel estimation problem, the algorithm is more generally applicable for greedy sparse recovery problems associated with estimating a sparse vector from measurements impaired by frequency offset.