Asymmetrical 4-QAM for Totally Blind APP Channel Estimation
Keywords
ESTIMATION
Abstract
A new two-dimensional blind channel estimation scheme for coherent detection of OFDM signals in a mobile environment is presented. The channel estimation is based on the A Posteriori Probability (APP) calculation algorithm. The time-variant channel transfer function is completely recovered without phase ambiguity with no need for any pilot or reference symbols by using an asymmetrical 4-QAM signal point constellation. We study the impact of the constellation asymmetry on system performance by means of Extrinsic Information Transfer (EXIT) and BER charts. Our approach maximizes the spectral efficiency by avoiding any reference or pilot symbols and minimizes the BER by using coherent demodulation.
Year
2003
Reference entry
Necker, M.C.; Sanzi, F. Asymmetrical 4-QAM for Totally Blind APP Channel Estimation
Proceedings of the 8th International OFDM-Workshop (InOWo '03), Hamburg, September 2003, pp. 75-79