In medical images, ROI (Region Of Interest) is an area which contains important information and must be stored without any distortion. We propose a digital watermarking method which avoids the distortion of the image data in ROI by embedding signature information into other area than the ROI. Signature image compressed by a progressive coding algorithm is used as the signature information. The ...

The paper studies the method active constellation extension (ACE) for increasing the channel capacity of orthogonal frequency-division multiplexing (OFDM) with a nonlinear power amplifier at the transmitter. It turns out that ACE is able to optimize the capacity but at the expense of an increased out-of-band radiation. In order to solve this issue, ACE is combined with the strategy clipping and...

A common figure of merit in multi-carrier systems is the error vector magnitude (EVM). A method for EVM computation of a multi-carrier signal without any underlying model (e.g., the Gaussianity assumption) was proposed in a previous work of the authors. However, it addressed only the case of identical constellations and power loadings in all tones. In practice, however, the constellation and po...