In this paper, we present a general formula for the capacity region of a general interference channel with two pairs of users. The formula shows that the capacity region is the union of a family of rectangles, where each rectangle is determined by a pair of spectral inf-mutual information rates. Although the presented formula is usually difficult to compute, it provides us useful insights into ...

Cognitive radio is a new concept of reusing licensed spectrum in an unlicensed manner. The motivation for cognitive radio is various measurements of spectrum utilization, that generally show unused resources in frequency, time and space. These ”spectrum holes” could be exploited by cognitive radios. Some studies suggest that the spectrum is extremely underutilized, and that these spectrum holes...

Difference spectroscopy is used to monitor bilirubin-protein interactions, to assess the residual binding capacity of proteins for bilirubin. A change in the difference spectra monitored at 482 nm is directly proportional to bound bilirubin up to a molar ratio of bilirubin to albumin of approximately 1; increasing bilirubin beyond the 1:1 molar ratio does not further change the difference spect...

Cognitive radio (CR) with spectrum-sharing feature is a promising technique to address the spectrum under-utilization problem in dynamically changing environments. In this paper, the achievable capacity gain of spectrum-sharing systems over dynamic fading environments is studied. To perform a general analysis, a theoretical fading model called hyper-fading model that is suitable to the dynamic ...

Recently, substantial attention has been paid to improve the spectral efficiency of communication setups using different spectrum sharing techniques. This paper aims to study the capacity of Rayleigh-fading spectrum sharing channels in the case where there is correlation between the fading channels. Assuming perfect channel state information, the channel capacity is obtained under both adaptive...

0 0 0 Abstract-The information theoretic capacity of frequency-hop spread-spectrum multiple-access communication is considered. In order to account for independent encoding and decoding and private (to the sender and receiver) hopping patterns an interference channel model is adopted with K sender-receiver pairs with the ith receiver only interested in the message transmitted by the ith sender....

In this paper, the performance of multichannel transmission in cognitive radio is studied. Both constraints and interference limitations are considered. The activities of the primary users (PU)s are initially detected by cognitive users (CU)s who perform sensing process over multiple channels. They transmit in a single channel at variable power and rates depending on the channel sensing decisio...

A novel mathematical method is presented to express the outage probability for a desired radio signal received from a mobile transmitter in the presence of multiple interfering signals with combined lognormal and Rayleigh fading. In contrast to previously reported analysis, this exact method avoids approximation of the pdf of the received powers of the various signals. This is useful in determi...

based on the convolutional model, a seismic trace is the convolution of seismic source wavelet and reflection coefficient series of the earth. seismic source wavelet estimation is one of the most important stages in processing and interpretation of seismic data. accurate estimation of wavelet increases the efficiency of the deconvolution and temporal resolution of seismic data. on the other han...