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

This paper deals with the application of Kalman Filtering (KF) techniques to the localization of a swarm of mobile agents in aWireless Sensor Network (WSN). In particular, both Extended (EKF) and Unscented (UKF) Kalman filters have been investigated referring to a typical urban scenario with energetic and resource constraints. A cooperation strategy among sensor nodes, based on a virtual diversity scheme, has been introduced allowing the swarm tracking under severe propagation conditions. The effectiveness of the proposed solution has been assessed by means of simulations concerning a squad of robots moving in realistic scenarios. It has been shown that UKF achieves a higher accuracy and reliability than EKF in localizing the barycenter of the robot squad. Further, the proposed solution provides advantages in terms of measurement update frequency and, hence, of energy saving.

Localization of a Swarm of Mobile Agents via Unscented Kalman Filtering

Heterogeneous network deployment represents one of the main enhancements of future LTE-A networks to increase spectrum efficiency. However, the achievable improvements are limited by the interference that arises from a co-channel allocation of the cells. This paper proposes two cognitive resource allocation methods that work using the angle of arrival of the signals instead of the channel state information. Both methods reduce the interference towards the macro-cell User Equipments (MUEs) using Zero Forcing Beamforming to avoid transmission in the MUEs direction. At the same time they maximize the capacity of the femto-cell with a suitable allocation of the time-frequency resources to the femto-cell UEs (FUEs). The performance of the proposed methods is compared with that of a conventional maximum gain beamforming and conventional zero forcing beamforming. The results show that the proposed methods achieve a good trade off between maximization of the femto-cell capacity and reduction of the interference level at the MUEs side.

Resource allocation schemes for cognitive LTE-A femto-cells using zero forcing beamforming and users selection

The lack of free frequency spectrum is becoming one of the most important problems in implementing novel wireless systems. The limited available spectrum and the inefficiency in the spectrum usage requires for a new communication paradigm to exploit the existing wireless spectrum. The key idea is based on the cognitive radio paradigm. Cognitive radio allows to different, independent networks to share a certain spectrum interval with low mutual interference. In the last years, one of the most important wireless system is the WiMAX, which is based on the OFDMA technique. The aim of this paper is to propose a cognitive networking environment where the primary network is constituted by an IEEE 802.16 network. Two approaches will be discussed for the secondary networks, by considering an ordinated technique and a collision resolution technique for both the network set-up and access control.

A Novel Cognitive Networking Scenario for IEEE 802.16 Networks

Developments in Wireless Network Prototyping, Design, and Deployment: Future Generations

The foreseen mass diffusion of mobile communication services will require the identification of suitable resource management strategies to utilize efficiently the available spectrum This paper refers to high?mobility cellular systems and carries out a performance evaluation for different channel assignment techniques that belong to the following classes: Fixed Channel Allocation (FCA), or Dynamic Channel Allocation (DCA) Suitable handoff prioritization techniques have been considered to obtain a high quality of service; in particular, the queueing of handoff requests and the use of guard channels have been investigated The resource management techniques have been compared in terms of the following parameters: the call blocking probability, the call dropping probability, the probability of unsuccessful call and the average number of channel rearrangements per call The joint use of DCA, guard channels, queueing of handoff requests and channel rearrangements has shown promising results for the management of both new call attempts and handoff requests

Romano Fantacci

Papers

Localization of a Swarm of Mobile Agents via Unscented Kalman Filtering

Resource allocation schemes for cognitive LTE-A femto-cells using zero forcing beamforming and users selection

A Novel Cognitive Networking Scenario for IEEE 802.16 Networks

Developments in Wireless Network Prototyping, Design, and Deployment: Future Generations

Performance evaluation of different resource management strategies in mobile cellular networks