Finite - Alphabet based Channel Estimation for OFDMand related Multi - Carrier

Finite-Alphabet based Channel Estimation for OFDM and related Multi-Carrier Systems Shengli Zhou and Georgios B. Giannakis1 Dept. of ECE, Univ. of Minnesota 200 Union Street SE, Minneapolis, MN 55455 Emails: fszhou,[email protected] Abstract | Novel blind channel estimators based on the nite alphabet property of information symbols are derived in this paper for OFDM systems. The resulting algorithms are applicable not only to standard OFDM transmitters with cyclic pre x, but also to the recently proposed zero padded OFDM transmissions. Based on FFT-processed received data, channel identi ability is guaranteed regardless of channel zero locations and various channel estimation algorithms become available by trading o complexity with performance. Unlike existing blind channel estimators, the inherent scalar ambiguity is reduced to nite phase values and is thus easily resolved. With PSK transmissions, channel estimation becomes possible even from a single OFDM symbol at high SNR. The algorithms are tested with simulations and also compared with existing alternatives in a realistic HIPERLAN/2 setting.