• Dr.P.Elavarasan
• Mr.A.Alexander

OFDM (Orthogonal Frequency Division Multiplexing) can be viewed either as a modulation or multiplexing technique. It is a special case of multicarrier transmission, where a single data stream is transmitted over a number of lower rate subcarriers. Increased robustness against frequency selective fading or narrowband interference is the primary benefit of using OFDM. MIMO (Multiple-input Multiple-output) is one of the smart antenna technology which uses multiple antennas at the transmitter and receiver side to increase the performance of the system. When paired with the OFDM technology, a MIMO communication system can deliver dependable high data rate transmission over broadband wireless channels. A wireless channel can be modeled as a sparse channel, in which the delay spread could be very large. Channel estimation is of crucial importance to MIMO-OFDM because the system performance depends on the quality of channel estimate. Channel estimation techniques can be categorized into three classes: training-based, blind and semi-blind methods. The common problem of the sparse channel estimation methods is that a large number of pilots are needed in order to render an accurate MST (Most Significant Taps) detection and effective channel estimation. An efficient semi- blind sparse channel estimation which combines the blind constraint with training based least square criterion for improving the system performance is to be estimated. For that it requires only a small number of OFDM symbols and pilot subcarriers.

Most Significant Taps (MST), multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM), semi-blind estimation, sparse channel estimation.

"Enhanced Semi-Blind Sparse Channel Estimation Technique for MIMO-OFDM System", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.10, Issue 7, page no.e662-e668, July-2023, Available :http://www.jetir.org/papers/JETIR2307471.pdf

"Enhanced Semi-Blind Sparse Channel Estimation Technique for MIMO-OFDM System", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.10, Issue 7, page no. ppe662-e668, July-2023, Available at : http://www.jetir.org/papers/JETIR2307471.pdf