On Comparison Of Pilot-Aided OFDM channel estimation algorithms

Orthogonal Frequency Division Multiplexing (OFDM) is an attractive modulation technique for communication between unmanned underwater vehicles (UUV) and a distant mother platform. The objective of this study is improving channel estimation accuracy in OFDM system because channel state information is required for signal detection at the receiver and its accuracy affects the overall performance of the system and it is essential to improve the channel estimation for more reliable communications. In this paper, the pilot signal estimation based on Least Square (LS), together with channel interpolation based on the discrete cosine transform, namely DCT-based LS estimator, is compared with LS channel estimation approaches and discussed. Two well known performance criteria: Mean Square Error (MSE) and Bit Error Rate (BER) are used for comparison by using Monte Carlo Simulations for 16 quartered amplitude modulation (16QAM). The results verify that the DCT-based LS estimator has a better performance for OFDM systems. Moreover, the effect of power limitation in terms of SNR and the number of pilots for a wireless channel is determined to compare the DCT-based LS estimator. The result indicates that the estimator with large number of pilots has better performance, but increases the computational complexity.