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

Digital multicarrier demodulator for regenerative communication satellites

This paper presents a framework for ns-3 (Network Simulator 3) of a particular wireless sensor network routing protocol, called RPL (IPv6 Routing Protocol for Low power and Lossy Networks). It will be presented with a design, its implementation and a simple example to demonstrate its operation. Finally, possible future developments are suggested and the appropriate conclusions will be drawn.

/pdf/ns-3-rpl-module-ipv6-routing-protocol-for-low-power-and-54hkeiyqhu.pdf

ns-3 RPL module: IPv6 routing protocol for low power and lossy networks

This paper deals with a modified version of the packet reservation multiple-access (PRMA) protocol suitable for integration of real-time (voice) and best effort (data) traffic in low Earth orbit (LEO) satellite communication systems. The proposed scheme differs from previous alternatives on the method adopted to handle access requests for voice and data terminals, and to transmit data messages. An analytical approach is proposed and validated in the case of voice and classical (i.e., geometric distributed) data traffic in order to derive system performance in terms of mean data message delay and voice packet dropping probability. However, in order to better highlight the advantages of the proposed approach typical interactive and background traffics types have been also considered. Performance comparisons with previous proposed PRMA protocols for voice and data transmission in LEO satellite communication systems are also shown in order to highlight the better behavior of the proposed scheme. Finally, a brief discussion concerning the extension of the proposed S-PRMA protocol to the case of different satellite communication systems is also provided.

Proposal and performance evaluation of an efficient multiple-access protocol for LEO satellite packet networks

This paper focuses on a new spectrum sensing algorithm based on the exploitation of the primary signal cyclostationarity property, which is used to avoid the intercell interference in a heterogeneous Long-Term Evolution Advanced (LTE-A) network. The performance of the proposed spectrum sensing method will be evaluated by means of a suitable analytical approach whose accuracy will be validated by comparing analytical predictions with simulation results under different communication channel propagation conditions. Furthermore, it will be shown that the proposed approach requires the lowest computational complexity among the cyclostationarity-based methods and allows better performance, even in the case of noise uncertainty, in terms of false alarm, detection probability, and deflection coefficient .

A Low-Complexity Cyclostationary Spectrum Sensing for Interference Avoidance in Femtocell LTE-A-Based Networks

This paper deals with a cognitive overlay IEEE 802.15.4e wireless sensor network relying on a low-complexity spectrum sensing technique. In particular, the paper critically compares two spectrum sensing schemes with the aim of identifying the most appropriate solution in terms of performance and implementation complexity. Furthermore, the paper provides an analytical framework to investigate the cognitive overlay IEEE 802.15.4e wireless sensor network behavior in terms of throughput, packet dropping probability, and energy efficiency. The obtained results clearly highlight the good behavior of the proposed approach without burdensome cost or complexity and its advantages for several emerging applications such as those supported by fog computing architecture.

Romano Fantacci

Papers

Digital multicarrier demodulator for regenerative communication satellites

ns-3 RPL module: IPv6 routing protocol for low power and lossy networks

Proposal and performance evaluation of an efficient multiple-access protocol for LEO satellite packet networks

A Low-Complexity Cyclostationary Spectrum Sensing for Interference Avoidance in Femtocell LTE-A-Based Networks

Performance Evaluation of an Adaptive Channel Allocation Technique for Cognitive Wireless Sensor Networks