Efficient CFO Estimation and Compensation Approach in OFDMA for Uplink Mobile WiMax

Abstract

Synchronization is a complex task in uplink Orthogonal Frequency Division Multiple Access (OFDMA) for Mobile WiMax as each user presents different Carrier Frequency Offsets (CFO). Synchronization begins with the CFO estimation and followed by the compensation of residual CFO present in the received signal. This paper deals with various techniques in time and frequency domains to compensate the effect of CFO on the received signal for different estimation techniques. SImple time domain MultiUser Interference Cancellation (SIMUIC) performs in time domain. It employs delays in the compensation of CFO while synchronizing the last user. Decorrelation Successive Interference Cancellation (DC-SC) and Integrated Estimation and Compensation (IEC) perform in frequency domain for the compensation of CFO. These approaches are more complex for Inter-Carrier Interference (ICI) cancellation. In this paper, we propose a new efficient CFO compensation technique in frequency domain for different estimation methods. This technique is a modified version of IEC for reducing the CFO effect on the received signal with lesser computations. Simulation results show that the modified IEC performs better than SIMUIC, DC-SC and IEC for different estimation methods.