601 research outputs found
Final report on the evaluation of RRM/CRRM algorithms
Deliverable public del projecte EVERESTThis deliverable provides a definition and a complete evaluation of the RRM/CRRM algorithms selected in D11 and D15, and evolved and refined on an iterative process. The evaluation will be carried out by means of simulations using the simulators provided at D07, and D14.Preprin
Advanced Wireless LAN
The past two decades have witnessed starling advances in wireless LAN technologies that were stimulated by its increasing popularity in the home due to ease of installation, and in commercial complexes offering wireless access to their customers. This book presents some of the latest development status of wireless LAN, covering the topics on physical layer, MAC layer, QoS and systems. It provides an opportunity for both practitioners and researchers to explore the problems that arise in the rapidly developed technologies in wireless LAN
Virtual PCF: Improving VoIP over WLAN performance with legacy clients
Abstract
Voice over IP (VoIP) is one of the fastest growing applications on the Internet.
Concurrently, 802.11 Wireless LANs (WLANs) have become ubiquitous in residential, enterprise, campus and public networks. Currently the majority of traffic on
WLANs is data traffic but as more people use wireless networks as their primary
access medium, a greater portion of traffic will be real-time traffic such as VoIP traffic. Unfortunately 802.11 networks are designed to handle delay-insensitive, bursty
traffic and perform poorly for VoIP streams. Experimental and analytical results
have shown that a single 802.11b access point operating at the maximum 11 Mbps
rate can support only 5 to 10 VoIP connections simultaneously. Intuitively, an 11 Mbps link should support approximately 85 bi-directional 64Kbps (G.711) streams.
The reason for this under-utilization lies primarily in the Distributed Coordination
Function (DCF) used by 802.11 MAC layer. The problem can be addressed by using the optional Point Coordination Function (PCF). However PCF is not widely
implemented in commodity hardware nor likely to be. There is a similar problem
with the proposed 802.11e standard for quality of service. To solve these problems
we propose Virtual PCF, a legacy-client compatible solution to increase the number
of simultaneous VoIP calls. We implement Virtual PCF, a scheme which employs
a variety of techniques to improve both uplink and downlink VoIP QoS. This alleviates delays and packet loss due to DCF contention and doubles the number of
supported VoIP sessions
An Innovative RAN Architecture for Emerging Heterogeneous Networks: The Road to the 5G Era
The global demand for mobile-broadband data services has experienced phenomenal growth over the last few years, driven by the rapid proliferation of smart devices such as smartphones and tablets. This growth is expected to continue unabated as mobile data traffic is predicted to grow anywhere from 20 to 50 times over the next 5 years. Exacerbating the problem is that such unprecedented surge in smartphones usage, which is characterized by frequent short on/off connections and mobility, generates heavy signaling traffic load in the network signaling storms . This consumes a disproportion amount of network resources, compromising network throughput and efficiency, and in extreme cases can cause the Third-Generation (3G) or 4G (long-term evolution (LTE) and LTE-Advanced (LTE-A)) cellular networks to crash.
As the conventional approaches of improving the spectral efficiency and/or allocation additional spectrum are fast approaching their theoretical limits, there is a growing consensus that current 3G and 4G (LTE/LTE-A) cellular radio access technologies (RATs) won\u27t be able to meet the anticipated growth in mobile traffic demand. To address these challenges, the wireless industry and standardization bodies have initiated a roadmap for transition from 4G to 5G cellular technology with a key objective to increase capacity by 1000Ă? by 2020 . Even though the technology hasn\u27t been invented yet, the hype around 5G networks has begun to bubble. The emerging consensus is that 5G is not a single technology, but rather a synergistic collection of interworking technical innovations and solutions that collectively address the challenge of traffic growth.
The core emerging ingredients that are widely considered the key enabling technologies to realize the envisioned 5G era, listed in the order of importance, are: 1) Heterogeneous networks (HetNets); 2) flexible backhauling; 3) efficient traffic offload techniques; and 4) Self Organizing Networks (SONs). The anticipated solutions delivered by efficient interworking/ integration of these enabling technologies are not simply about throwing more resources and /or spectrum at the challenge. The envisioned solution, however, requires radically different cellular RAN and mobile core architectures that efficiently and cost-effectively deploy and manage radio resources as well as offload mobile traffic from the overloaded core network.
The main objective of this thesis is to address the key techno-economics challenges facing the transition from current Fourth-Generation (4G) cellular technology to the 5G era in the context of proposing a novel high-risk revolutionary direction to the design and implementation of the envisioned 5G cellular networks. The ultimate goal is to explore the potential and viability of cost-effectively implementing the 1000x capacity challenge while continuing to provide adequate mobile broadband experience to users. Specifically, this work proposes and devises a novel PON-based HetNet mobile backhaul RAN architecture that: 1) holistically addresses the key techno-economics hurdles facing the implementation of the envisioned 5G cellular technology, specifically, the backhauling and signaling challenges; and 2) enables, for the first time to the best of our knowledge, the support of efficient ground-breaking mobile data and signaling offload techniques, which significantly enhance the performance of both the HetNet-based RAN and LTE-A\u27s core network (Evolved Packet Core (EPC) per 3GPP standard), ensure that core network equipment is used more productively, and moderate the evolving 5G\u27s signaling growth and optimize its impact.
To address the backhauling challenge, we propose a cost-effective fiber-based small cell backhaul infrastructure, which leverages existing fibered and powered facilities associated with a PON-based fiber-to-the-Node/Home (FTTN/FTTH)) residential access network. Due to the sharing of existing valuable fiber assets, the proposed PON-based backhaul architecture, in which the small cells are collocated with existing FTTN remote terminals (optical network units (ONUs)), is much more economical than conventional point-to-point (PTP) fiber backhaul designs. A fully distributed ring-based EPON architecture is utilized here as the fiber-based HetNet backhaul. The techno-economics merits of utilizing the proposed PON-based FTTx access HetNet RAN architecture versus that of traditional 4G LTE-A\u27s RAN will be thoroughly examined and quantified. Specifically, we quantify the techno-economics merits of the proposed PON-based HetNet backhaul by comparing its performance versus that of a conventional fiber-based PTP backhaul architecture as a benchmark.
It is shown that the purposely selected ring-based PON architecture along with the supporting distributed control plane enable the proposed PON-based FTTx RAN architecture to support several key salient networking features that collectively significantly enhance the overall performance of both the HetNet-based RAN and 4G LTE-A\u27s core (EPC) compared to that of the typical fiber-based PTP backhaul architecture in terms of handoff capability, signaling overhead, overall network throughput and latency, and QoS support. It will also been shown that the proposed HetNet-based RAN architecture is not only capable of providing the typical macro-cell offloading gain (RAN gain) but also can provide ground-breaking EPC offloading gain.
The simulation results indicate that the overall capacity of the proposed HetNet scales with the number of deployed small cells, thanks to LTE-A\u27s advanced interference management techniques. For example, if there are 10 deployed outdoor small cells for every macrocell in the network, then the overall capacity will be approximately 10-11x capacity gain over a macro-only network. To reach the 1000x capacity goal, numerous small cells including 3G, 4G, and WiFi (femtos, picos, metros, relays, remote radio heads, distributed antenna systems) need to be deployed indoors and outdoors, at all possible venues (residences and enterprises)
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Multimedia delivery in the future internet
The term âNetworked Mediaâ implies that all kinds of media including text, image, 3D graphics, audio
and video are produced, distributed, shared, managed and consumed on-line through various networks,
like the Internet, Fiber, WiFi, WiMAX, GPRS, 3G and so on, in a convergent manner [1]. This white
paper is the contribution of the Media Delivery Platform (MDP) cluster and aims to cover the Networked
challenges of the Networked Media in the transition to the Future of the Internet.
Internet has evolved and changed the way we work and live. End users of the Internet have been confronted
with a bewildering range of media, services and applications and of technological innovations concerning
media formats, wireless networks, terminal types and capabilities. And there is little evidence that the pace
of this innovation is slowing. Today, over one billion of users access the Internet on regular basis, more
than 100 million users have downloaded at least one (multi)media file and over 47 millions of them do so
regularly, searching in more than 160 Exabytes1 of content. In the near future these numbers are expected
to exponentially rise. It is expected that the Internet content will be increased by at least a factor of 6, rising
to more than 990 Exabytes before 2012, fuelled mainly by the users themselves. Moreover, it is envisaged
that in a near- to mid-term future, the Internet will provide the means to share and distribute (new)
multimedia content and services with superior quality and striking flexibility, in a trusted and personalized
way, improving citizensâ quality of life, working conditions, edutainment and safety.
In this evolving environment, new transport protocols, new multimedia encoding schemes, cross-layer inthe
network adaptation, machine-to-machine communication (including RFIDs), rich 3D content as well as
community networks and the use of peer-to-peer (P2P) overlays are expected to generate new models of
interaction and cooperation, and be able to support enhanced perceived quality-of-experience (PQoE) and
innovative applications âon the moveâ, like virtual collaboration environments, personalised services/
media, virtual sport groups, on-line gaming, edutainment. In this context, the interaction with content
combined with interactive/multimedia search capabilities across distributed repositories, opportunistic P2P
networks and the dynamic adaptation to the characteristics of diverse mobile terminals are expected to
contribute towards such a vision.
Based on work that has taken place in a number of EC co-funded projects, in Framework Program 6 (FP6)
and Framework Program 7 (FP7), a group of experts and technology visionaries have voluntarily
contributed in this white paper aiming to describe the status, the state-of-the art, the challenges and the way
ahead in the area of Content Aware media delivery platforms
A VOICE PRIORITY QUEUE (VPQ) SCHEDULER FOR VOIP OVER WLANs
The Voice over Internet Protocol (VoIP) application has observed the fastest
growth in the world of telecommunication. The Wireless Local Area Network
(WLAN) is the most assuring of technologies among the wireless networks, which
has facilitated high-rate voice services at low cost and good flexibility. In a voice
conversation, each client works as a sender and as a receiver depending on the
direction of traffic flow over the network.
A VoIP application requires a higher throughput, less packet loss and a higher
fairness index over the network. The packets of VoIP streaming may experience drops
because of the competition among the different kinds of traffic flow over the network.
A VoIP application is also sensitive to delay and requires the voice packets to arrive
on time from the sender to the receiver side without any delay over WLANs.
The scheduling system model for VoIP traffic is still an unresolved problem. A
new traffic scheduler is necessary to offer higher throughput and a higher fairness
index for a VoIP application. The objectives of this thesis are to propose a new
scheduler and algorithms that support the VoIP application and to evaluate, validate
and verify the newly proposed scheduler and algorithms with the existing scheduling
algorithms over WLANs through simulation and experimental environment.
We proposed a new Voice Priority Queue (VPQ) scheduling system model and
algorithms to solve scheduling issues. VPQ system model is implemented in three
stages. The first stage of the model is to ensure efficiency by producing a higher
throughput and fairness for VoIP packets. The second stage will be designed for
bursty Virtual-VoIP Flow (Virtual-VF) while the third stage is a Switch Movement
(SM) technique. Furthermore, we compared the VPQ scheduler with other well
known schedulers and algorithms. We observed in our simulation and experimental
environment that the VPQ provides better results for the VoIP over WLANs
QoS support in satellite and wireless networks : study under the network simulator (NS-2)
Aquest projecte es basa en l'estudi de l'oferiment de qualitat de servei en xarxes wireless i satel·litals. Per aixĂČ l'estudi de les tĂšcniques de cross-layer i del IEEE 802.11e ha sigut el punt clau per al desenvolupament teĂČric d'aquest estudi. Usant el simulador de xarxes network simulator, a la part de simulacions es plantegen tres situacions: l'estudi de la xarxa satel·lital, l'estudi del mĂštode d'accĂ©s HCCA i la interconnexiĂł de la xarxa satel·lital amb la wireless. Encara que aquest Ășltim punt, incomplet en aquest projecte, ha de ser la continuaciĂł per a futures investigacions.Este proyecto se basa en el estudio del ofrecimiento de calidad de servicio en redes wireless y satelitales. Por eso el estudio de las tĂ©cnicas de cross-layer y del IEEE 802.11eha sido el punto clave para el desarrollo teĂłrico de este estudio. Usando el simulador de redes network simulator, en la parte de simulaciones se plantean tres situaciones: el estudio de la red satelital, el estudio del mĂ©todo de acceso HCCA y la interconexiĂłn de la red satelital con la wireless. Aunque este Ășltimo punto, incompleto en este proyecto, tiene que ser la continuaciĂłn para futuras investigaciones.This project is based on the study of offering quality of service in satellite and wireless networks. For that reason the study of the techniques of cross-layer and the IEEE 802.11e has been the key point for the theoretical development of this study. Using the software network simulator, in the part of simulations three situations consider: the study of the satellite network, the study of the access method HCCA and the interconnection of the satellite network with the wireless. Although this last point, incomplete in this work, must be the continuation for future investigations
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