1,312 research outputs found
EVM as generic QoS trigger for heterogeneous wieless overlay network
Fourth Generation (4G) Wireless System will integrate heterogeneous wireless
overlay systems i.e. interworking of WLAN/ GSM/ CDMA/ WiMAX/ LTE/ etc with
guaranteed Quality of Service (QoS) and Experience (QoE).QoS(E) vary from
network to network and is application sensitive. User needs an optimal mobility
solution while roaming in Overlaid wireless environment i.e. user could
seamlessly transfer his session/ call to a best available network bearing
guaranteed Quality of Experience. And If this Seamless transfer of session is
executed between two networks having different access standards then it is
called Vertical Handover (VHO). Contemporary VHO decision algorithms are based
on generic QoS metrics viz. SNR, bandwidth, jitter, BER and delay. In this
paper, Error Vector Magnitude (EVM) is proposed to be a generic QoS trigger for
VHO execution. EVM is defined as the deviation of inphase/ quadrature (I/Q)
values from ideal signal states and thus provides a measure of signal quality.
In 4G Interoperable environment, OFDM is the leading Modulation scheme (more
prone to multi-path fading). EVM (modulation error) properly characterises the
wireless link/ channel for accurate VHO decision. EVM depends on the inherent
transmission impairments viz. frequency offset, phase noise,
non-linear-impairment, skewness etc. for a given wireless link. Paper provides
an insight to the analytical aspect of EVM & measures EVM (%) for key
management subframes like association/re-association/disassociation/ probe
request/response frames. EVM relation is explored for different possible
NAV-Network Allocation Vectors (frame duration). Finally EVM is compared with
SNR, BER and investigation concludes EVM as a promising QoS trigger for OFDM
based emerging wireless standards.Comment: 12 pages, 7 figures, IJWMN 2010 august issue vol. 2, no.
MIPv6 Experimental Evaluation using Overlay Networks
The commercial deployment of Mobile IPv6 has been hastened by the concepts of Integrated
Wireless Networks and Overlay Networks, which are present in the notion of the
forthcoming generation of wireless communications. Individual wireless access networks
show limitations that can be overcome through the integration of different technologies
into a single unified platform (i.e., 4G systems). This paper summarises practical experiments
performed to evaluate the impact of inter-networking (i.e. vertical handovers) on
the Network and Transport layers. Based on our observations, we propose and evaluate a
number of inter-technology handover optimisation techniques, e.g., Router Advertisements
frequency values, Binding Update simulcasting, Router Advertisement caching, and Soft
Handovers. The paper concludes with the description of a policy-based mobility support
middleware (PROTON) that hides 4G networking complexities from mobile users, provides
informed handover-related decisions, and enables the application of different vertical
handover methods and optimisations according to context.Publicad
Recommended from our members
Multimedia delivery in the future internet
The term “Networked Media” 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 citizens’ 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 “on the move”, 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
Mobile Computing in Digital Ecosystems: Design Issues and Challenges
In this paper we argue that the set of wireless, mobile devices (e.g.,
portable telephones, tablet PCs, GPS navigators, media players) commonly used
by human users enables the construction of what we term a digital ecosystem,
i.e., an ecosystem constructed out of so-called digital organisms (see below),
that can foster the development of novel distributed services. In this context,
a human user equipped with his/her own mobile devices, can be though of as a
digital organism (DO), a subsystem characterized by a set of peculiar features
and resources it can offer to the rest of the ecosystem for use from its peer
DOs. The internal organization of the DO must address issues of management of
its own resources, including power consumption. Inside the DO and among DOs,
peer-to-peer interaction mechanisms can be conveniently deployed to favor
resource sharing and data dissemination. Throughout this paper, we show that
most of the solutions and technologies needed to construct a digital ecosystem
are already available. What is still missing is a framework (i.e., mechanisms,
protocols, services) that can support effectively the integration and
cooperation of these technologies. In addition, in the following we show that
that framework can be implemented as a middleware subsystem that enables novel
and ubiquitous forms of computation and communication. Finally, in order to
illustrate the effectiveness of our approach, we introduce some experimental
results we have obtained from preliminary implementations of (parts of) that
subsystem.Comment: Proceedings of the 7th International wireless Communications and
Mobile Computing conference (IWCMC-2011), Emergency Management: Communication
and Computing Platforms Worksho
Seamless Vertical Handover in WiFi and WiMAX Networks using RSS and Motion Detection: An Investigation
In this paper, we propose a decision making algorithm for seamless vertical handover between WiFi hotspots and an overlay WiMAX network. The inputs to the algorithm are the WiFi received signal strength (RSS) and estimated end-to-end TCP handover latency. Simulation of the algorithm using Matlab® reveals that the distance from the WiFi reception boundary at which handover must be initiated if it is to be seamless increases with both end-to-end TCP/IP handover latency and the speed of the mobile terminal towards or away from the WiFi access point. We conclude that RSS-based seamless handovers need to be augmented with network layer information if they are to be optimal
Handover in Mobile Wireless Communication Network - A Review
Mobility is the characteristics of mobile communication that makes it irresistible by all and sundry. The whole world is now engaging in wireless communication as it provides users\u27 ability to communicate on-the-go. This is achieved by transferring users from a radio network to another. This process is called handover. Handover occurs either by cell crossing or by deterioration in signal quality of the current channel. The continuation of an active call is a critical characteristic in cellular systems. Brief overview of handover, handover type, commonly used handover parameters, some methods employed in the literature and we present the convergent point for furtherance in the area of mobile wireless communication Handover
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