There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity. >

On the capacity of a cellular CDMA system

Information Theory and Reliable Communication

: This thesis applies neural network feature selection techniques to multivariate time series data to improve prediction of a target time series. Two approaches to feature selection are used. First, a subset enumeration method is used to determine which financial indicators are most useful for aiding in prediction of the S&P 500 futures daily price. The candidate indicators evaluated include RSI, Stochastics and several moving averages. Results indicate that the Stochastics and RSI indicators result in better prediction results than the moving averages. The second approach to feature selection is calculation of individual saliency metrics. A new decision boundary-based individual saliency metric, and a classifier independent saliency metric are developed and tested. Ruck's saliency metric, the decision boundary based saliency metric, and the classifier independent saliency metric are compared for a data set consisting of the RSI and Stochastics indicators as well as delayed closing price values. The decision based metric and the Ruck metric results are similar, but the classifier independent metric agrees with neither of the other metrics. The nine most salient features, determined by the decision boundary based metric, are used to train a neural network and the results are presented and compared to other published results. (AN)

/pdf/nonlinear-time-series-analysis-1j3a35n4y3.pdf

Nonlinear Time Series Analysis.

This document provides updates to IEEE Std 802.16's MIB for the MAC, PHY and asso- ciated management procedures in order to accommodate recent extensions to the standard.

IEEE Standard for Local and Metropolitan Area Networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems Draft Amendment: Management Information Base Extensions

Future mobile communication systems will be characterized by the integration of several networks at the system level. Therefore, the satellite component and the terrestrial one will use as far as possible the same protocols. Accordingly, this paper investigates the possibility of using the packet-reservation multiple-access (PRMA) technique as a medium access control protocol for low-Earth orbit-mobile satellite systems (LEO-MSSs). A modified version of the PRMA protocol, named PRMA with hindering states (PRMA-HSs), is also proposed in order to attain better performance.

/pdf/performance-analysis-of-an-improved-prma-protocol-for-low-32tih2ybnv.pdf

Performance analysis of an improved PRMA protocol for low Earth orbit-mobile satellite systems

This paper deals with a cognitive radio approach based on a noncooperative spectrum sensing technique for applications in a very-high-frequency (VHF) aeronautical communications system to detect idle VHF channels and allocate them to an additional overlay system or secondary users. In particular, the focus here is on a spectrum sensing technique belonging to the class of energy detectors based on the Welch windowed periodogram. The performance of the proposed detector is presented in terms of the missed detection probability of the primary user under different application conditions. The obtained results and resulting implementation complexity highlight better behavior of the proposed detector with respect to alternative schemes previously proposed in the literature on this subject.

Performance Evaluation of a Spectrum-Sensing Technique for Cognitive Radio Applications in B-VHF Communication Systems

This paper deals with an efficient dynamic channel allocation (DCA) technique suitable for applications in mobile satellite cellular networks. A cost function is defined to allow an optimum selection of channels to be allocated on demand. A mobility model suitable for low earth orbit (LEO) satellite systems is presented. The performance of the novel DCA technique in terms of call blocking probability has been derived by simulations. The obtained results are compared with those achieved by a fixed channel allocation (FCA) technique to show a better behaviour.

/pdf/performance-analysis-of-a-dynamic-channel-allocation-1otbvsc0kn.pdf

Performance analysis of a dynamic channel allocation technique for satellite mobile cellular networks

This paper deals with a signal processing precorrelation method to detect the presence of interference at a global navigation satellite system (GNSS) receiver site. In particular, a nonparametric spectral estimation approach based on the Welch windowed periodogram will be considered here. The performance of the proposed detector, in terms of detection probability, for a given false-alarm probability value, will be derived by means of an analytical approach and resorting to computer simulations. A performance comparison with previously proposed precorrelation methods will also be presented in order to highlight the better behavior of the proposed approach that makes it suitable for safety of life (SoL) applications.

Performance Evaluation of a Precorrelation Interference Detection Algorithm for the GNSS Based on Nonparametrical Spectral Estimation

The fifth generation (5G) of wireless communication systems is considered the key technology to enable a wide range of application scenarios and the effective spreading of the smart city concept. Vertical business use cases, specifically designed for the future 5G city, will have a strong economical and social impact. For this reason, ongoing 5G field trials have to test newly deployed technologies as well as the capability of 5G to create a new digital economy. This paper describes the 5G field trial environment that was launched in Italy at the end of 2017. The aim is to evaluate the capability of the 5G network of supporting innovative services with reference to suitably designed key performance indicators and to evaluate the opportunities offered by these services. Indeed, vertical business use cases, specifically designed for the future 5G city, with a strong economic and social impact, are under implementation and will be evaluated. In particular, the paper provides a detailed description of the deployment of an actual complete integrated 5G network. It shows how 5G is effective enabling technology for a wide range of vertical business and use cases. Indeed, its flexibility allows to satisfy completely different performance requirements of real services. Some preliminary results, obtained during the first phase, are presented for a smart mobility scenario.

/pdf/a-real-case-of-implementation-of-the-future-5g-city-2oxzbnz56b.pdf

Romano Fantacci

Papers

Performance analysis of an improved PRMA protocol for low Earth orbit-mobile satellite systems

Performance Evaluation of a Spectrum-Sensing Technique for Cognitive Radio Applications in B-VHF Communication Systems

Performance analysis of a dynamic channel allocation technique for satellite mobile cellular networks

Performance Evaluation of a Precorrelation Interference Detection Algorithm for the GNSS Based on Nonparametrical Spectral Estimation

A Real Case of Implementation of the Future 5G City