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

The development of strategies, technologies and tools to enhance user collaboration around disasters has become an emergent field, that has triggered the integration of different technologies in order to efficiently drive decision making in emergency management (EM) In this paper, we critically review the existing strategies and technologies for EM and outline a new approach based on the functional integration of the mining of social networks with the capabilities of sensor networks to collect data and the availability of a dedicated telecommunication system to exchange information securely and reliably The focus is placed on different strategies for decision support and for alert and information dissemination Effectiveness of the proposed approach is validated by discussing performances of its implementation in a system for the prevention and the management of natural disasters developed with a regional research project

Integration of heterogeneous information sources for an effective emergency management

Upcoming sixth-generation networks have to be carefully designed to offer support to a wide range of human-centric applications, typically computationally intensive and heavily dependent on human perception. This paper proposes a human-in-the-loop-based resource allocation approach found on the joint use of matching theory and stochastic network calculus principles to efficiently address tasks offloading issues within a sixth-generation network environment. The considered matching game approach is characterized by externalities, whose stability is properly discussed here. In particular, by focusing on virtual reality services, the paper aims at maximizing the average service reliability in terms of ability in guaranteeing a proper quality of experience target, i.e., keeping the end-to-end delay below a suitable threshold, by the proper exploitation of the human cognitive limitations. Finally, the effectiveness of the proposed human-in-the-loop-based resource allocation approach is verified by proving comparisons with simulation results and conventional brain-agnostic strategies. 

Human-in-the-loop virtual reality offloading scheme in wireless 6G Terahertz networks

In this paper, the performance of some efficient ARQ schemes which make use of repeated transmissions of the same data block and compound detection are analysed. The repeated transmission of the same data block involves repeated transmission of each symbol of the data block. At the receiving end, compound detection formed of a soft detection jointly with a classical hard detection is performed by using all the received copies of the same symbol. The throughput efficiencies for the proposed ARQ schemes are analytically derived in closed form and optimized with respect to the number of copies to be transmitted for each data block. It will be shown that the optimized ARQ schemes proposed in this paper achieve better performance than classical ARQ schemes, in particular under high error rate conditions.

Efficient ARQ schemes for error control of satellite channels

Carrier frequency, carrier phase, multipath profile, delay values as well as fading characteristics are important for coherent detection. Several DS-CDMA receivers have been investigated, but mainly with the assumption of perfect estimation of those parameters. This paper deals with the impact of channel phase and path delay estimation errors to the performance of pre and post-combining blind adaptive linear minimum mean square error (LMMSE) receivers. Comparisons are made also with the conventional RAKE receiver. The results show that channel phase estimation errors degrade almost equally the performance of blind adaptive LMMSE and RAKE receivers. Delay estimation errors by over 20% of chip time cause the loss of advantages of LMMSE detection.

/pdf/sensitivity-of-blind-adaptive-lmmse-single-user-receivers-to-1szu7qu8sz.pdf

Sensitivity of blind adaptive LMMSE single-user receivers to path delay and phase estimation errors in multipath fading channel

Wireless local area networks (WLANs) are one of the most promising access technologies for the upcoming fourth-generation wireless communication systems. In the last few years, several research efforts have been devoted to investigate possible multiple access schemes capable of supporting real-time traffic as well as best-effort data transmissions. In particular, the use of suitable transmission schemes allows not only to achieve higher data-rates, but also to optimize the allocation of traffic in the radio resources depending on the service requirements. In this paper we propose a multiple access scheme for a WLAN supporting real-time (voice) and best-effort (data) services, which exploits the presence of a broadband multiuser wireless access scheme such as orthogonal frequency division multiplexing (OFDM). OFDM allows dividing the radio bandwidth into several sub-bands, thus permitting a flexible resource allocation strategy to be deployed, while satisfying quality of service (QoS) requirements. A high overall network capacity in terms of simultaneously active users is achieved by effectively exploiting the multiuser capabilities offered by OFDM, together with a good service differentiation. A suitable theoretical analysis for the considered protocol has been carried out by applying the equilibrium point analysis (EPA) method, and computer simulation results have been compared with analytical predictions.

https://link.springer.com/content/pdf/10.1007%2Fs11276-006-7522-1.pdf

Romano Fantacci

Papers

Integration of heterogeneous information sources for an effective emergency management

Human-in-the-loop virtual reality offloading scheme in wireless 6G Terahertz networks

Efficient ARQ schemes for error control of satellite channels

Sensitivity of blind adaptive LMMSE single-user receivers to path delay and phase estimation errors in multipath fading channel

Performance analysis of a multiple access protocol for voice and data support in broadband wireless LANs