Low-cost blind carrier frequency offset estimator for down-link MIMO multicarrier systems

Abstract

Under perfect synchronisation conditions, communication systems using multiple transmit and receive antennas, known as the multiple input multiple output (MIMO) technique, along with the multicarrier transmission technique can achieve very high transmission data rates, bandwidth efficiency and robustness to the channel frequency selective fading. In a practical system, however, the presence of a carrier frequency offset (CFO), due to lack of perfect synchronisation, causes a severe degradation in the overall system performance. A low-cost blind CFO estimator is proposed for the downlink of the MIMO multicarrier system, which is based on the null subcarriers concept and Taylor's series expansion. The theoretical mean squared error (MSE) of the proposed CFO estimator is also derived. It is shown in particular, that the computational complexity of the proposed estimator is significantly low, yet its performance is good.