Impact of Sampling Theorem on Pilot Aided Channel Estimation for OFDM based Multi-Carrier System

Wireless multimedia has created boom in today’s era. It is just a fraction of seconds to get information at any time anywhere. All these because of the development of multicarrier communication system, OFDM, which provides high data rate as well as high speed. With that channel estimation becomes more challenging. In such multicarrier systems the time varying channel is often estimated based on different algorithms. These algorithms are basically categorised as blind and non-blind channel estimation techniques. Due to the limitations of blind algorithms such as requirement of the statistical knowledge of received signal, the non-blind i.e. pilot aided channel estimation have become more popular. In such techniques known symbols to the receiver called pilots are inserted in the OFDM data symbols and they should be close enough to fulfil the Nyquist sampling theorem for pilot spacing [1]. This paper shows the simulation results to prove the sampling theorem based on the channel estimation in the multipath fading scenario. Keywords— Channel Estimation, LS (Least Square), MMSE (Minimum Mean Square Error), Nyquist Sampling Theorem, OFDM (Orthogonal Frequency Division Multiplexing).