Combined Channel and Clipping Level Estimation in OFDM with MMSE Equalizer

Orthogonal Frequency Division Multiplexing (OFDM) has been recently applied wide in wireless communication systems, as a result of its high rate, transmission capability with high information measure, potency and its strength to multipath delay .Channel estimation is an important drawback in OFDM system. Channel estimation forms the center of any orthogonal frequency division multiplexing (OFDM) based mostly wireless communication receiver. Frequency domain pilot aided channel estimation techniques are either least squares (LS) based or minimum mean square error (MMSE) based. LS based techniques are computationally less complex. Unlike MMSE ones, they do not require a priori knowledge of channel statistics. However, the mean square error (MSE) performance of the channel estimator incorporating MMSE based techniques is better compared to that obtained with the incorporation of LS based techniques. We propose an alternative optimization algorithm which uses frequency-domain block-type training symbols, and prove that this algorithm always converges, at least to a local optimum point. Then, we calculate the Crame-´r - Rao lower bound, and show that the proposed estimator attains the bound. Ranjith T K | Sreevarsha V"Combined Channel and Clipping Level Estimation in OFDM with MMSE Equalizer" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-3 , April 2018, URL: http://www.ijtsrd.com/papers/ijtsrd11380.pdf http://www.ijtsrd.com/engineering/electronics-and-communication-engineering/11380/combined-channel-and-clipping-level-estimation-in-ofdm-with-mmse-equalizer/ranjith-t-k