28,215 research outputs found
Simulation of QoS based call admission schemes for DS-CDMA
Code division multiple-access (CDMA) has been receiving considerable attention as the core multiple-access technology in the development of upcoming ubiquitous personal communication service (PCS) system with flexible quality of service (QoS) requirements at any time and anywhere. Moreover, future wireless networks are expected to integrate different types of multimedia traffic, such as voice, data, and compressed images and video. This work aims to investigate the resource allocation problem for wireless direct sequence spread-spectrum CDMA cellular networks supporting heterogeneous multimedia applications where individual users have different QoS requirements. We propose optimal rate and power distribution approaches for source allocation to individual users, subject to a constraint on the total available bandwidth, to maximize the per-cell capacity and maintain the quality of service (QoS) for different multimedia services. Connection oriented admission control schemes based on the required QoS are proposed in this thesis. Several policies are introduced for use in CDMA network. Simulation results show that the proposed Radio Resource Management scheme can achieve both effective QoS guarantee and efficient resource utilization
Handover mechanisms in next generation heterogeneous wireless networks
University of Technology, Sydney. Faculty of Engineering.New access technologies such as IEEE 802.11 Wireless LAN are emerging as a new
means of public wireless access. Working on public unlicensed bands, they are capable
of providing high speed data services, but small radio coverage. The third generation
cellular networks such as Universal Mobile Telecommunications System (UMTS)
provide wide radio coverage, but have limited data rates. An integration of these
heterogeneous wireless networks is expected to be an effective means of providing high
speed data access in wide radio coverage in the Next Generation (NG) wireless
networks. When a mobile user moves across these networks, it has to perform handover
to maintain its services. During a handover, it is pivotal to guarantee both service
continuity and service quality, which ensure that handover can be made seamlessly. To
provide ubiquitous services, an extensive collaboration between network operators is
anticipated to be an economic solution. Providing seamless handover and ubiquitous
services in heterogeneous wireless networks presents many new research challenges.
The objective of this thesis is to develop new handover management techniques for
supporting seamless handover and facilitating ubiquitous services in heterogeneous
wireless networks. More specifically, new techniques for dealing with the extensive
collaboration of NG network operators, and new techniques that enable the interworking
of heterogeneous wireless technologies.
Regarding the extensive collaboration of network operators, a neighbour network trust
information retrieval scheme is proposed for global roaming. With this scheme, an
access network can obtain network trust information of its nearby access networks
without relying on direct links with them. The retrieved trust information can be
provided to an attached mobile user later to assist it with global roaming. Next, a
handover decision algorithm that uses network trust information is presented. The
proposed algorithm guarantees much more reliable handover in a multiple-operator
environment. It is demonstrated how quality of service is maintained and overall
network load is balanced using the proposed handover algorithm. The thesis moves
further to a proxy based authentication localisation scheme that focuses on the handover
across two networks without a trust relation. The proposed scheme provides a secure
and effective method of localising authentication at a third-party entity during a
handover. This avoids resorting to a mobile’s home network for identity verification in
a handover, and thus, greatly reduces handover latency.
In terms of the interworking of heterogeneous wireless technologies, the thesis presents
a multi-interface mobile terminal model for media independent handover. The presented
model addresses the challenge of working with heterogeneous wireless technologies
from the perspective of a mobile terminal. Under the proposed multi-interface
architecture, a mobile terminal can work with multiple network interfaces, and still uses
common upper layer protocols such as Mobile IPv4. Being compatible with IEEE
802.21 framework, it uses a cross-layer design approach
MIRAI Architecture for Heterogeneous Network
One of the keywords that describe next-generation wireless communications is "seamless." As part of the e-Japan Plan promoted by the Japanese Government, the Multimedia Integrated Network by Radio Access Innovation project has as its goal the development of new technologies to enable seamless integration of various wireless access systems for practical use by 2005. This article describes a heterogeneous network architecture including a common tool, a common platform, and a common access. In particular, software-defined radio technologies are used to develop a multiservice user terminal to access different wireless networks. The common platform for various wireless networks is based on a wireless-supporting IPv6 network. A basic access network, separated from other wireless access networks, is used as a means for wireless system discovery, signaling, and paging. A proof-of-concept experimental demonstration system is available
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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
WiMAX Basics From Deployments to PHY Improvements
© ASEE 2014WiMAX (Worldwide Interoperability for Microwave Access) is an emerging broadband wireless technology for providing Last mile solutions for supporting higher bandwidth and multiple service classes with various quality of service requirement. The unique architecture of the WiMAX MAC and PHY layers that uses OFDMA to allocate multiple channels with different modulation schema and multiple time slots for each channel allows better adaptation of heterogeneous user’s requirements. The main architecture in WiMAX uses PMP (Point to Multipoint), Mesh mode or the new MMR (Mobile Multi hop Mode) deployments where scheduling and multicasting have different approaches. In PMP SS (Subscriber Station) connects directly to BS (Base Station) in a single hop route so channel conditions adaptations and supporting QoS for classes of services is the key points in scheduling, admission control or multicasting, while in Mesh networks SS connects to other SS Stations or to the BS in a multi hop routes, the MMR mode extends the PMP mode in which the SS connects to either a relay station (RS) or to Bs. Both MMR and Mesh uses centralized or distributed scheduling with multicasting schemas based on scheduling trees for routing. In this paper a broad study is conducted About WiMAX technology PMP and Mesh deployments from main physical layers features with differentiation of MAC layer features to scheduling and multicasting approaches in both modes of operations
WIMAX Basics from PHY Layer to Scheduling and Multicasting Approaches
WiMAX (Worldwide Interoperability for Microwave Access) is an emerging broadband wireless technology for providing Last mile solutions for supporting higher bandwidth and multiple service classes with various quality of service requirement. The unique architecture of the WiMAX MAC and PHY layers that uses OFDMA to allocate multiple channels with different modulation schema and multiple time slots for each channel allows better adaptation of heterogeneous user’s requirements. The main architecture in WiMAX uses PMP (Point to Multipoint), Mesh mode or the new MMR (Mobile Multi hop Mode) deployments where scheduling and multicasting have different approaches. In PMP SS (Subscriber Station) connects directly to BS (Base Station) in a single hop route so channel conditions adaptations and supporting QoS for classes of services is the key points in scheduling, admission control or multicasting, while in Mesh networks SS connects to other SS Stations or to the BS in a multi hop routes, the MMR mode extends the PMP mode in which the SS connects to either a relay station (RS) or to Bs. Both MMR and Mesh uses centralized or distributed scheduling with multicasting schemas based on scheduling trees for routing. In this paper a broad study is conducted About WiMAX technology PMP and Mesh deployments from main physical layers features with differentiation of MAC layer features to scheduling and multicasting approaches in both modes of operations
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