CFO Estimation for Multi-user Uplink SC-FDMA Using Null Subcarrier and Deterministic Approach

Abstract

Estimating multiple carrier frequency offsets (CFOs) in the presence of multiple users is a crucial task in a single carrier frequency division multiple access (SC-FDMA) uplink system. We proposed a blind and fast CFO estimator using null subcarriers for SC-FDMA systems. The proposed method utilizes the property of measuring the energy within the null subcarriers for the estimation of multiple CFOs. A cost function is derived that minimizes the signal power at null subcarriers while estimating the correct CFOs. The complexity arising due to larger iteration in the grid search method has been further minimized by using the deterministic approach. The mean square error (MSE) is used to investigate the performance of the proposed estimator. The simulation results are validated by theoretical performance analysis and compared with existing works over frequency selective fading channel environment.