The frequencyand time-domain expressions are derived for the signal-to-noise power ratio (SNR) of an ideal Rake combiner output in a direct sequence spread spectrum (DSSS) mobile communication system. The derived SNR expressions make it possible to estimate the SNR statistics after Rake combining for an arbitrary spreading chip rate in the frequencyselective multipath channel. key words: spread...

In this paper, we propose a method –based on the discrete evolutionary transform (DET)– to estimate the instantaneous frequency of a signal embedded in noise or noise-like signals. The DET provides a representation for non-stationary signals and a time-frequency kernel that permit us to obtain the time-dependent spectrum of the signal. We will show the instantaneous phase and the corresponding ...

Many-core systems are susceptible to attacks launched by thermal covert channel (TCC) attacks. Detection of TCC often relies on the use threshold-based approaches or variants, and a countermeasure thwart can be applied only after an attack is deemed present. In this article, we describe direct sequence spread spectrum (DSSS)-based TCC, where its data modulated pseudo-random bit sequence. Unfort...

Recently, blind multi-user detection has become an important topic in code division multiple access (CDMA) systems. Direct-Sequence Spread Spectrum (DSSS) signals are well-known due to their low probability of detection, and secure communication. In this article, the problem of blind multi-user detection is studied in variable processing gain direct-sequence code division multiple access (VPG D...

Spread spectrum has been used as a technique for secure communications for a long time. For still image watermarking, spread spectrum has been the method of choice for some time. In this paper we argue that spread spectrum in the form of CDMA has a more natural application in the watermarking of uncompressed digital video. The reason for this sentiment is that digital video, by virtue of its ti...

Spread spectrum communication technology, compared with the conventional communication technology, has many characteristics, such as a low interception rate, strong anti-noise performance, noise immunity, information hiding and multiple access communication. Widely used in military communication and civil communication at present, it is the core technology in the third generation mobile communi...

In the context of spectrum surveillance, a method to recover the code of direct sequence spread spectrum signal is presented, whereas the receiver has no knowledge of the transmitter’s spreading sequence. The approach is based on an artificial neural network which is forced to model the received signal. Experimental results show that the method provides a good estimation, even when the signal p...