Investigation and Improvement of Maximum Likelihood Channel Estimator in OFDM Systems

Frequency offsets are the most destructive effects to the orthogonality between carriers, also known as Inter-Carrier-Interference (ICI) in OFDM systems. This offset can be corrected by implementing a proper correction scheme which relies on channel estimation techniques such as Maximum Likelihood Channel Estimator (MMLE). Further improvements enhance the reliability, Accuracy and Quality of Service (QoS) of OFDM. This paper studies MMLE behavior to improve the limitation and the overall performance of channel estimation process using matlab simulation software and propose an improved version of MMLE which shows the noticeable degradation of Bit Error Rate (BER). Simulation results shows that lower Bit Error Rates (BER) can be achieved using this improved method which further achieves more orthogonal OFDM carriers and less ICI.