Covert OFDM transmission using cyclic prefix

摘要

Methods for secure OFDM communications include changing the length of OFDM symbols in a pseudo-random fashion by appending a totally random signal to some of the OFDM symbols. An adaptive cyclic prefix is provided for covert and spectrally efficient communication. A developed PN based random data addition provides further security by removing the chance of combining synchronization information over several OFDM symbols.