Information Theory and Reliable Communication

Cloud Radio Access Network (C-RAN) is a novel mobile network architecture which can address a number of challenges the operators face while trying to support growing end-user's needs. The main idea behind C-RAN is to pool the Baseband Units (BBUs) from multiple base stations into centralized BBU Pool for statistical multiplexing gain, while shifting the burden to the high-speed wireline transmission of In-phase and Quadrature (IQ) data. C-RAN enables energy efficient network operation and possible cost savings on baseband resources. Furthermore, it improves network capacity by performing load balancing and cooperative processing of signals originating from several base stations. This paper surveys the state-of-the-art literature on C-RAN. It can serve as a starting point for anyone willing to understand C-RAN architecture and advance the research on C-RAN.

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Cloud RAN for Mobile Networks—A Technology Overview

In network design, the gap between theory and practice is woefully broad. This book narrows it, comprehensively and critically examining current network design models and methods. You will learn where mathematical modeling and algorithmic optimization have been under-utilized. At the opposite extreme, you will learn where they tend to fail to contribute to the twin goals of network efficiency and cost-savings. Most of all, you will learn precisely how to tailor theoretical models to make them as useful as possible in practice. Throughout, the authors focus on the traffic demands encountered in the real world of network design. Their generic approach, however, allows problem formulations and solutions to be applied across the board to virtually any type of backbone communication or computer network. For beginners, this book is an excellent introduction. For seasoned professionals, it provides immediate solutions and a strong foundation for further advances in the use of mathematical modeling for network design. (Less)

Routing, Flow, And Capacity Design In Communication And Computer Networks

Network devices put packets on an Internet link, and multiplex, or superpose, the packets from different active connections.

Internet Traffic Tends Toward Poisson and Independent as the Load Increases

A communications network has a plurality of nodes interconnected by an optical transmission medium. The transmission medium is capable of a carrying a plurality of wavelengths organized into bands. A filter at each node for drops a band associated therewith and passively forwards other bands through the transmission medium. A device is provided at each node for adding a band to the transmission medium. Communication can be established directly between a pair of nodes in the network sharing a common band without the active intervention of any intervening node. This allows the network to be protocol independent. Also, the low losses incurred by the passive filters permit relatively long path lengths without optical amplification.

WDM optical network with passive pass-through at each node

This article reports a review of the most significant issues related to network architectures and technologies which will enable the realization of future optical Internet networks. The design of such networks has to take into consideration the peculiar characteristics of Internet traffic. Several architectures have been proposed to provide optical networking solutions, based on wavelength-division multiplexing and compatible with the IP world. These architectures are presented briefly, and the main advantages and drawbacks are discussed. Furthermore, advanced network architectures are reported. In particular, two network paradigms are illustrated and discussed: the optical transparent packet network and optical burst switching. Finally, the key technologies are illustrated.

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Architectural and technological issues for future optical Internet networks

The introduction of optical technology in the path layer of the transport network is expected to allow scalable and modular networks to be realized. In this paper, different optical cross-connect architectures, based either on space division or wavelength division switching, are analyzed. A comparative investigation is accomplished considering three issues of primary importance: cross-connect modularity, complexity, and transmission performance. In particular, the transmission performance of a generic path through the network is evaluated by upgrading a previously published analytical model, so to more accurately take into account the in-band crosstalk arising in the cross-connect.

Optical path technologies: a comparison among different cross-connect architectures

An optical cross-connect node architecture interfaces plural optical fiber input and output links, each link containing plural wavelength channels. In one embodiment, the input links are connected to a single optical coupler, or alternatively, to an associated one of plural optical couplers. Pairs of tunable optical filters and optical wavelength converters are each connected to an output port of the optical coupler, or to each of the plural optical couplers, and perform wavelength channel routing and switching in the wavelength domain, i.e., without the need for any optical space switch. In other embodiments, an additional input wavelength converter is connected to each input fiber link to convert the plural wavelength channels on each link to different, non-interferring wavelengths. This prevents wavelength contention in the optical coupler to which the input wavelength converters are connected. New fiber links may be added in modular fashion without significant impact on the pre-existing optical cross-connect structure. Similarly, new wavelength channels may also be multiplexed onto existing fibers to provide wavelength modularity without having to reconfigure the node.

A modular optical cross-connect architecture with optical wavelenght switching

This article discusses a novel approach for realizing traffic engineering in the framework of new-generation multilayer networks based on the GMPLS paradigm. In particular, the proposed traffic engineering system is able to dynamically react to traffic changes while at the same time fulfilling QoS requirements for different classes of service. The proposed solution consists of a hybrid routing approach, based on both offline and online methods, and a novel bandwidth management system that handles priority, preemption mechanisms, and traffic rerouting in order to concurrently accommodate the largest amount of traffic and fulfill QoS requirements. The bandwidth resources of the network are effectively exploited by means of "elastic" utilization of the bandwidth. The main building blocks and operations of the system are reported, and the major advantages are discussed.

A traffic engineering system for multilayer networks based on the GMPLS paradigm

The impact of transmission related issues on the routing strategies for transparent all-optical wavelength division multiplexed (WDM) transport networks is analyzed in this paper. Three different categories of routing algorithms are analyzed: algorithms based on the wavelength path (WP) strategy, based on the virtual wavelength path (VWP) strategy and requiring only a limited number of wavelength converters in the network partial virtual wavelength path (PVWP). It results that the PVWP allows a saving in network devices with respect to the WP similar those permitted by the VWP also attaining transmission performances near those attained by the WP that are quite better that those attained by the VWP.

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Roberto Sabella

Papers

Architectural and technological issues for future optical Internet networks

Optical path technologies: a comparison among different cross-connect architectures

A modular optical cross-connect architecture with optical wavelenght switching

A traffic engineering system for multilayer networks based on the GMPLS paradigm

Impact of transmission performance on path routing in all-optical transport networks