Carrier Frequency Offset Estimation for Orthogonal Frequency Division Multiplexing

• Main Author: Challakere, Nagaravind
• Format: Others
• Published: DigitalCommons@USU 2012
• Subjects: Adaptive algorithm; Carrier Frequency Offset (CFO) Estimation; Data-aided; Minimum Mean Squared Error; MSER; OFDM; Electrical and Computer Engineering
• Online Access: https://digitalcommons.usu.edu/etd/1423; https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=2384&context=etd

This thesis presents a novel method to solve the problem of estimating the carrier frequency set in an Orthogonal Frequency Division Multiplexing (OFDM) system. The approach is based on the minimization of the probability of symbol error. Hence, this approach is called the Minimum Symbol Error Rate (MSER) approach. An existing approach based on Maximum Likelihood (ML) is chosen to benchmark the performance of the MSER-based algorithm. The MSER approach is computationally intensive. The thesis evaluates the approximations that can be made to the MSER-based objective function to make the computation tractable. A modified gradient function based on the MSER objective is developed which provides better performance characteristics than the ML-based estimator. The estimates produced by the MSER approach exhibit lower Mean Squared Error compared to the ML benchmark. The performance of MSER-based estimator is simulated with Quaternary Phase Shift Keying (QPSK) symbols, but the algorithm presented is applicable to all complex symbol constellations.