In this letter, a hybrid multi-domain index modulation scheme based on spreading codes domain and beam is proposed. our design, the information bit stream divided into two parts: one for covert transmission using of code other directional to improve error ratio (BER) performance in desired direction prevent eavesdropping. Then, joint boundaries statistical theory, average probabilities legitima...

Orthogonal frequency division multiplexing with index modulation (OFDM-IM), stands out among conventional communication technologies, as it uses the indices of available transmit entities. Thanks to such an approach, offers a novel method for transmission extra data bits. Recent years have seen great interest in chaos-based communications. The spectrum-spreading signals used chaotic signal tech...

This paper presents the technique to dynamically enhance the power efficiency of PWM class-D amplifier over a wide range of modulation indexes. The power stage of amplifier is segmented into several small stages and selectively enabled according to the power demand (i.e. modulation indexes). The capability of power delivery is dynamically adjusted to minimize the power loss in case of different...

For copyright protection of digital image, we present an energy quantization modulation approach for digital image watermarking in this paper. First, we introduce the concept of local energy index of a coefficient block in approximation sub-band of an image. Second, an energy quantization modulation technique is developed to modulate the local energy index of each coefficient block. Moreover, i...

In this paper the notion of amplitude modulation of chaotic signals is introduced, similar to amplitude modulation of harmonic signal. Necessary conditions for modulation and demodulation of chaotic carrier are discussed. In particular, the type of chaotic carrier is discussed from the point of view of optimal demodulation. Demodulation accuracy estimates are also presented. Index terms – Chaot...