Blind multiple carrier frequency offsets estimation for OFDM with distributed multi-antenna receiver

Abstract

In this paper, two blind carrier frequency offset (CFO) estimators for orthogonal frequency division multiplexing (OFDM) with distributed multi-antenna receiver are designed. We first propose a pairing based efficient estimator (PBEE), where multiple CFOs are divided and then estimated in pairs of two with a carefully designed cost function. This cost function is proven to be exactly a cosine function parameterized by the two CFOs even with the effect of noise. Consequently, the CFOs estimate can be obtained in closed-form after a one-dimensional search. Moreover, in order to improve the estimation performance, we further develop the maximum likelihood (ML) estimator. The computationally inefficient multi-dimensional search of ML estimator can be solved by introducing an extra one-step adjustment to the PBEE. Both the two estimators support fully loaded transmissions, which can save the spectral efficiency. Numerical results are provided to corroborate the proposed studies.