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

Praise for the Third Edition: "This is one of the best books available. Its excellent organizational structure allows quick reference to specific models and its clear presentation . . . solidifies the understanding of the concepts being presented."IIE Transactions on Operations EngineeringThoroughly revised and expanded to reflect the latest developments in the field, Fundamentals of Queueing Theory, Fourth Edition continues to present the basic statistical principles that are necessary to analyze the probabilistic nature of queues. Rather than presenting a narrow focus on the subject, this update illustrates the wide-reaching, fundamental concepts in queueing theory and its applications to diverse areas such as computer science, engineering, business, and operations research.This update takes a numerical approach to understanding and making probable estimations relating to queues, with a comprehensive outline of simple and more advanced queueing models. Newly featured topics of the Fourth Edition include:Retrial queuesApproximations for queueing networksNumerical inversion of transformsDetermining the appropriate number of servers to balance quality and cost of serviceEach chapter provides a self-contained presentation of key concepts and formulae, allowing readers to work with each section independently, while a summary table at the end of the book outlines the types of queues that have been discussed and their results. In addition, two new appendices have been added, discussing transforms and generating functions as well as the fundamentals of differential and difference equations. New examples are now included along with problems that incorporate QtsPlus software, which is freely available via the book's related Web site.With its accessible style and wealth of real-world examples, Fundamentals of Queueing Theory, Fourth Edition is an ideal book for courses on queueing theory at the upper-undergraduate and graduate levels. It is also a valuable resource for researchers and practitioners who analyze congestion in the fields of telecommunications, transportation, aviation, and management science.

Fundamentals of Queueing Theory

Information Theory and Reliable Communication

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

Ultra Wideband Signals and Systems in Communication Engineering

Providing end-to-end communication in heterogeneous Internet working environments is a challenge. Handover delay is one of the problematic issues that users are face in the heterogynous networks. However, in the case of both WiMAX and WiFi technologies located at the same base station (BS); the vertical handover (VHO) delay will be less compared with two conventional WiMAX/WiFi heterogonous networks with two different wireless Internet service providers (WISP). However, protocol conversion is still adding delay and jitter for data exchange between the needed two technologies. In this paper, In order to reduce the delay in protocol conversion, a new design for WiWi (WiMAX and WiFi) adaptation layer is proposed. The realization of the interworking between these two standards is discussed and evaluated.

WiFi/WiMAX Heterogeneous Seamless Handover

Handover (HO) mechanism is one of the critical operations in mobile WiMAX. It takes place when a mobile station (MS) moves from a serving base station (BS) to another BS. However, the HO latency in mobile WiMAX is still an issue that may affect continuity of real-time application sessions such as Voice over Internet Protocol (VoIP). This paper presents performance comparison of some HO mechanisms for real-time applications in mobile WiMAX, including HO, cross-layer HO, pre-coordination HO, passport HO mechanisms and fast intra-network and cross-layer HO (FINCH). Each one of these mechanisms reduces HO latency, especially during downlink traffic; however, they still produce insufficient HO latency during uplink traffic. Except for FINCH, they do not consider the scenario of HO between BSs that belong to different access service network-gateways (ASN-GWs) or to different connectivity service networks (CSNs); these two cases cause extra layer 3 (L3) HO latency.

Review of handover mechanisms to support triple play in mobile WiMAX

Short-range wireless systems have recently gained a lot of attention to provide seamless,
multimedia communications around a user-centric concept in so called Wireless Personal Area
Networks (WPAN). Ultra-Wide Band (UWB) technology presents itself as a good candidate for the
Physical Layer (PHY) of WPAN, both for high and low data rate applications. Many ongoing
developments of Ultra-Wide Band (UWB) system concentrate mainly on the physical layer, without
significant considerations being given to the medium access techniques especially for targeted ad-hoc
networking scenarios. Here, we further refine the framework, the network challenges, and defines a
global network cost function, which takes into account both physical, and network layers parameters to
derive general guidelines for ad-hoc networks based on UWB technology.

Ultra Wide Band (UWB) Ad-hoc Networks: Review and Trends

A novel technique of producing multiwavelength laser source was described utilising a linear cavity of hybrid Brillouin/Erbium fibre laser (BEFL). Twenty-two stable output lasers with 10.88 GHz line spacing were obtained from this architecture at 1557.5 nm that was at the peak of Erbium gain. The requirement of an internal feedback that is commonly used in a ring configuration to generate cascaded Brillouin Stokes for multiple wavelengths operation was achieved by the proposed linear cavity design.

Hybrid Brillouin/Erbium fibre laser in a linear cavity for multi-wavelength communication systems

Host mobility in mobile ad hoc networks causes failure of wireless links between nodes and breaks all the routes that use these links. Consequently, route reconstructions are needed, which is one of the most critical problems for this type of wireless networks. The number of route reconstructions can be reduced if more reliable wireless links are used. Also by these links, stable clusters can be constructed as is needed in cluster based protocols. Reliable routing protocols for mobile ad hoc networks use many link reliability metrics for finding these links; four of the most commonly used are “Link Expiration Time”, “Probabilistic Link Reliable Time”, “Link Packet Error Rate” and “Link Received Signal Strength”. It is shown that these metrics enhance the reliability and reduce the number of route reconstructions, but to the best of our knowledge there is no report that compare their efficiencies. In this paper, we make this comparison in different network conditions and discuss their optimal applications. Then, a new cross layer metric is proposed that combines the aforementioned metrics according to their efficiency by means of a unit weight function. Simulation results show that by using all these metrics, the number of route reconstructions is reduced, and for the proposed one the result is better than the others.

Borhanuddin Mohd Ali

Papers

WiFi/WiMAX Heterogeneous Seamless Handover

Review of handover mechanisms to support triple play in mobile WiMAX

Ultra Wide Band (UWB) Ad-hoc Networks: Review and Trends

Hybrid Brillouin/Erbium fibre laser in a linear cavity for multi-wavelength communication systems

A Cross Layer Metric for Discovering Reliable Routes in Mobile Ad Hoc Networks