Radio propagation simulation tools are important for prediction and verification of the radio signal coverage by individual transmitters or transmitter networks such as mobile phone cellular networks. In the case of a large geographic area with a relative high resolution, the simulation can become computationally demanding, taking a considerable amount of time to accomplish. Parallel processing...

We present a high resolution radio image of SDSS 0836+0054 identified recently as the most distant radio-detected quasar at a redshift of z = 5.82. The observation was carried out with ten antennas of the European VLBI Network, spread from Europe to China and South Africa, at 1.6 GHz frequency on 2002 June 8. The source is detected with a total flux density of 1.1 mJy, equal to its flux density...

The hot star wind momentum problem η = Ṁ3∞/(L/c) ≫ 1 is revisited, and it is shown that the conventional belief, that it can be solved by a combination of clumping of the wind and multiple scattering of photons, is not self-consistent for optically thick clumps. Clumping does reduce the mass loss rate Ṁ, and hence the momentum supply, required to generate a specified radio emission measure ε, w...

The center idea behind the software radio architecture is to place analog-to-digital and digital-to-analog converters as near the antenna as possible, leaving the implementation of the most radio functionality to a programmable micro or signal processor. One way to accomplish this in a radio receiver front end is by direct downconverting the desired radio frequency (RF) signal to a target inter...

In this paper we present a novel QoS framework on the network layer for 5G terminals with vertical multihoming and multi-streaming capabilities by using radio networks aggregation. The proposed framework is leading to high performance utility networks with QoS provisioning for real-time multimedia services by achieving low packet delays, stochastic queuing network stability and highest mobile b...

Software-defined radio (SDR) is an emerging technology that facilitates having multiple wireless communication protocols on one device. Previous work has shown that current W-CDMA, GPS, GSM, and WiMAX applications can run on this class of device while consuming significant processing power. Next generation wireless networks require speeds in excess of 50Mbps. Some of the fastest AES software im...

A method for speech expressiveness change detection is presented which combines a dimensional analysis of speech expression, a Principal Component Analysis technique, as well as multiple regression analysis. From the three inferred rates of activation, valence, and involvement, two PCA-factors explain 97 % of the variance of the judges’ evaluations of a corpus of radio show interaction. The mul...

In this paper, we address the problem of designing time hopping codes for multiple access communication impulse radio systems. Time hopping techniques are first reviewed, and performance in terms of correlation properties and Power Spectral Density are given. A new family of time hopping codes is presented, and performance are derived. Finally, advantages and disadvantages of different time hop...

As the deployment of new wireless devices and applications is growing rapidly there is an increase in demand for wireless radio spectrum. Researchers show that more than 70% of available spectrum is not used efficiently. For efficient utilization of spectrum we need to know whether the spectrum is used by primary user or not which is called Spectrum Sensing. The concept Cognitive Radio is propo...

The performance of Multiple Symbol Differential Detection applied to differentially encoded QPSK signals, is examined by simulation in the mobile radio channel with slow Rayleigh and Rician fading, and cochannel interference (CCI). Performance gains observed in the slow R i c h fading channel when compared to conventional differential detection, are maintained in the CCI environment. Using a si...