@INPROCEEDINGS {7504,
author={D. Neves and C. Ribeiro and A.  Silva and A. Gameiro},
doi={},
booktitle={Vehicular Technology Conference: VTC-Spring},
title={Channel Estimation Schemes for OFDM Relay-Assisted Systems},
year={2009},
month={April},
volume={69th},
pages={1-5} 
}