Blind Residual Carrier Frequency Offset and Timing Offset Estimation Using Improved Minimum Output Variance Approaches in Uplink MC-CDMA Systems

This paper deals with blind residual carrier frequency offset (CFO) and timing offset (TO) estimation based on minimum output variance (MOV) criterion without devoting training sequence and pilot symbol for uplink multicarrier-code division multiple access (MC-CDMA) systems. It has been shown that the performance of MOV estimator is degraded because the effect of noise and wideband spread-spectrum signals. In conjunction with spreading code-aided and subspace projection techniques, we present an improved code-aided MOV (ICMOV) estimator to achieve the high accuracy estimate for the noisy case. Due to more accuracy residual CFO estimate can provide more accuracy residual TO estimate, this paper also present a decision-directed ICMOV (DD-ICMOV) approach to improve the estimation performance of ICMOV estimator. Computer simulations are provided for illustrating the effectiveness of the proposed approaches.