83 research outputs found
Quantifying Potential Energy Efficiency Gain in Green Cellular Wireless Networks
Conventional cellular wireless networks were designed with the purpose of
providing high throughput for the user and high capacity for the service
provider, without any provisions of energy efficiency. As a result, these
networks have an enormous Carbon footprint. In this paper, we describe the
sources of the inefficiencies in such networks. First we present results of the
studies on how much Carbon footprint such networks generate. We also discuss
how much more mobile traffic is expected to increase so that this Carbon
footprint will even increase tremendously more. We then discuss specific
sources of inefficiency and potential sources of improvement at the physical
layer as well as at higher layers of the communication protocol hierarchy. In
particular, considering that most of the energy inefficiency in cellular
wireless networks is at the base stations, we discuss multi-tier networks and
point to the potential of exploiting mobility patterns in order to use base
station energy judiciously. We then investigate potential methods to reduce
this inefficiency and quantify their individual contributions. By a
consideration of the combination of all potential gains, we conclude that an
improvement in energy consumption in cellular wireless networks by two orders
of magnitude, or even more, is possible.Comment: arXiv admin note: text overlap with arXiv:1210.843
Cross-layer design of multi-hop wireless networks
MULTI -hop wireless networks are usually defined as a collection of nodes
equipped with radio transmitters, which not only have the capability to
communicate each other in a multi-hop fashion, but also to route each others’ data
packets. The distributed nature of such networks makes them suitable for a variety of
applications where there are no assumed reliable central entities, or controllers, and
may significantly improve the scalability issues of conventional single-hop wireless
networks.
This Ph.D. dissertation mainly investigates two aspects of the research issues
related to the efficient multi-hop wireless networks design, namely: (a) network
protocols and (b) network management, both in cross-layer design paradigms to
ensure the notion of service quality, such as quality of service (QoS) in wireless mesh
networks (WMNs) for backhaul applications and quality of information (QoI) in
wireless sensor networks (WSNs) for sensing tasks. Throughout the presentation of
this Ph.D. dissertation, different network settings are used as illustrative examples,
however the proposed algorithms, methodologies, protocols, and models are not
restricted in the considered networks, but rather have wide applicability.
First, this dissertation proposes a cross-layer design framework integrating
a distributed proportional-fair scheduler and a QoS routing algorithm, while using
WMNs as an illustrative example. The proposed approach has significant performance
gain compared with other network protocols. Second, this dissertation proposes
a generic admission control methodology for any packet network, wired and
wireless, by modeling the network as a black box, and using a generic mathematical
0. Abstract 3
function and Taylor expansion to capture the admission impact. Third, this dissertation
further enhances the previous designs by proposing a negotiation process,
to bridge the applications’ service quality demands and the resource management,
while using WSNs as an illustrative example. This approach allows the negotiation
among different service classes and WSN resource allocations to reach the optimal
operational status. Finally, the guarantees of the service quality are extended to
the environment of multiple, disconnected, mobile subnetworks, where the question
of how to maintain communications using dynamically controlled, unmanned data
ferries is investigated
Quality aspects of Internet telephony
Internet telephony has had a tremendous impact on how people communicate.
Many now maintain contact using some form of Internet telephony.
Therefore the motivation for this work has been to address the quality aspects
of real-world Internet telephony for both fixed and wireless telecommunication.
The focus has been on the quality aspects of voice communication,
since poor quality leads often to user dissatisfaction. The scope of the work
has been broad in order to address the main factors within IP-based voice
communication.
The first four chapters of this dissertation constitute the background
material. The first chapter outlines where Internet telephony is deployed
today. It also motivates the topics and techniques used in this research.
The second chapter provides the background on Internet telephony including
signalling, speech coding and voice Internetworking. The third chapter
focuses solely on quality measures for packetised voice systems and finally
the fourth chapter is devoted to the history of voice research.
The appendix of this dissertation constitutes the research contributions.
It includes an examination of the access network, focusing on how calls are
multiplexed in wired and wireless systems. Subsequently in the wireless
case, we consider how to handover calls from 802.11 networks to the cellular
infrastructure. We then consider the Internet backbone where most of our
work is devoted to measurements specifically for Internet telephony. The
applications of these measurements have been estimating telephony arrival
processes, measuring call quality, and quantifying the trend in Internet telephony
quality over several years. We also consider the end systems, since
they are responsible for reconstructing a voice stream given loss and delay
constraints. Finally we estimate voice quality using the ITU proposal PESQ
and the packet loss process.
The main contribution of this work is a systematic examination of Internet
telephony. We describe several methods to enable adaptable solutions
for maintaining consistent voice quality. We have also found that relatively
small technical changes can lead to substantial user quality improvements.
A second contribution of this work is a suite of software tools designed to
ascertain voice quality in IP networks. Some of these tools are in use within
commercial systems today
Modelling, Dimensioning and Optimization of 5G Communication Networks, Resources and Services
This reprint aims to collect state-of-the-art research contributions that address challenges in the emerging 5G networks design, dimensioning and optimization. Designing, dimensioning and optimization of communication networks resources and services have been an inseparable part of telecom network development. The latter must convey a large volume of traffic, providing service to traffic streams with highly differentiated requirements in terms of bit-rate and service time, required quality of service and quality of experience parameters. Such a communication infrastructure presents many important challenges, such as the study of necessary multi-layer cooperation, new protocols, performance evaluation of different network parts, low layer network design, network management and security issues, and new technologies in general, which will be discussed in this book
Recommended from our members
Analytical Modelling of Scheduling Schemes under Self-similar Network Traffic. Traffic Modelling and Performance Analysis of Centralized and Distributed Scheduling Schemes.
High-speed transmission over contemporary communication networks has
drawn many research efforts. Traffic scheduling schemes which play a critical role in
managing network transmission have been pervasively studied and widely
implemented in various practical communication networks. In a sophisticated
communication system, a variety of applications co-exist and require differentiated
Quality-of-Service (QoS). Innovative scheduling schemes and hybrid scheduling
disciplines which integrate multiple traditional scheduling mechanisms have
emerged for QoS differentiation. This study aims to develop novel analytical models
for commonly interested scheduling schemes in communication systems under more
realistic network traffic and use the models to investigate the issues of design and
development of traffic scheduling schemes.
In the open literature, it is commonly recognized that network traffic exhibits
self-similar nature, which has serious impact on the performance of communication
networks and protocols. To have a deep study of self-similar traffic, the real-world
traffic datasets are measured and evaluated in this study. The results reveal that selfsimilar
traffic is a ubiquitous phenomenon in high-speed communication networks
and highlight the importance of the developed analytical models under self-similar
traffic.
The original analytical models are then developed for the centralized
scheduling schemes including the Deficit Round Robin, the hybrid PQGPS which
integrates the traditional Priority Queueing (PQ) and Generalized Processor Sharing (GPS) schemes, and the Automatic Repeat reQuest (ARQ) forward error control
discipline in the presence of self-similar traffic.
Most recently, research on the innovative Cognitive Radio (CR) techniques
in wireless networks is popular. However, most of the existing analytical models still
employ the traditional Poisson traffic to examine the performance of CR involved
systems. In addition, few studies have been reported for estimating the residual
service left by primary users. Instead, extensive existing studies use an ON/OFF
source to model the residual service regardless of the primary traffic. In this thesis, a PQ theory is adopted to investigate and model the possible service left by selfsimilar
primary traffic and derive the queue length distribution of individual
secondary users under the distributed spectrum random access protocol
Lightweight mobile and wireless systems: technologies, architectures, and services
1Department of Information and Communication Systems Engineering (ICSE), University of the Aegean, 81100 Mytilene, Greece 2Department of Information Engineering and Computer Science (DISI), University of Trento, 38123 Trento, Italy 3Department of Informatics, Alexander Technological Educational Institute of Thessaloniki, Thessaloniki, 574 00 Macedonia, Greece 4Centre Tecnologic de Telecomunicacions de Catalunya (CTTC), 08860 Barcelona, Spain 5North Carolina State University (NCSU), Raleigh, NC 27695, US
A Survey on 5G Usage Scenarios and Traffic Models
The fifth-generation mobile initiative, 5G, is a
tremendous and collective effort to specify, standardize, design,
manufacture, and deploy the next cellular network generation.
5G networks will support demanding services such as enhanced
Mobile Broadband, Ultra-Reliable and Low Latency Communications and massive Machine-Type Communications, which will
require data rates of tens of Gbps, latencies of few milliseconds
and connection densities of millions of devices per square kilometer. This survey presents the most significant use cases expected
for 5G including their corresponding scenarios and traffic models.
First, the paper analyzes the characteristics and requirements for
5G communications, considering aspects such as traffic volume,
network deployments, and main performance targets. Secondly,
emphasizing the definition of performance evaluation criteria
for 5G technologies, the paper reviews related proposals from
principal standards development organizations and industry
alliances. Finally, well-defined and significant 5G use cases are
provided. As a result, these guidelines will help and ease the
performance evaluation of current and future 5G innovations, as
well as the dimensioning of 5G future deployments.This work is partially funded by the Spanish Ministry of
Economy and Competitiveness (project TEC2016-76795-C6-4-R)H2020
research and innovation project 5G-CLARITY (Grant No. 871428)Andalusian Knowledge Agency (project A-TIC-241-UGR18)
- …