Linear block precoding for blind channel estimation in OFDM systems

We propose a novel approach for blind channel estimation over frequency selective channels in OFDM system. By introducing a non-redundant unitary precoder for each pair of blocks before they enter the OFDM system, the channel can be identified up to a complex scalar ambiguity based upon a simple cross-correlation operations applied to successive received signal blocks. It is shown that the proposed approach not only maintains the transmission power, but also provides multipath diversity and bandwidth efficiency.