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Vol.3 No.2
June 15, 2007
Editorial
(101-102)
A. Hafid, P. Dini, and K. Liu
Research articles:
Efficient JPEG2000 Image Transmission Using RCPT Codes Based on Channel
Operating Regions
(103-117)
W.-L. Liu and D.G. Daut
The latest wavelet-based image compression standard,
JPEG2000, provides five different progressive modes. Due to the embedded
structure used in the codestream syntax, the received bits after
transmitting over noisy channels exhibit severe error sensitivity and
experience error propagation. In this paper, we propose an efficient
JPEG2000 transmission system with separate design methods for image
header and data packets. First, two hybrid FEC/ARQ schemes operating
over an AWGN channel to realize near error-free transmission of the
image header are studied. Second, compressed data packets for different
quality layers are protected using an unequal error protection (UEP)
method. A set of rate compatible punctured turbo codes (RCPT) is used
for forward error correction. In addition to the rate-distortion based
rate allocation models, a practical channel segmentation method, which
avoids the complicated optimization computation, is presented for code
rate selection based on channel operating regions. Using simulation
methods, it has been found that the choice of code rates is best guided
by segmentation of the SNR into operating regions of the AWGN channel.
Experimental results show that the proposed system outperforms systems
using equal error protection (EEP) up to $9~dB$ while significantly
reducing the computation complexity compared to other UEP systems. One
major contribution of the system developed in this paper is the separate
treatments of the compressed data in the JPEG2000 codestream. Another
contribution is that of a rate selection method for practical channel
codes. The resulting system design approach yields improved overall
image transmission quality with minimal bandwidth expansion.
Inter-Domain SLS
Negotiation for End-to-End UMTS/IMS QoS
(118-130)
Q.T. Nguyen-Vuong and N.
Agoulmine
The Third Generation Partnership Project (3GPP) has
defined an IP Multimedia Subsystem (IMS) for Third Generation (3G)
networks. IMS offers services for any type of IP communication that can
be provided by third parties independently of underlying access
technology. The main challenge for IMS in the future is to support
proper interworking with underlying resource management in order to
provide the end-to-end QoS assurance. This problem has been addressed by
the 3GPP as well as within several projects. However, the proposed
solutions have concerned mainly the UMTS Radio Access Network (RAN) and
core network domains while the resources at the border with the external
IP domains are considered as static. In this paper, we introduce an
enhancement of the 3GPP QoS architecture that allows a dynamic and
automatic resource provisioning between the UMTS network and the
external IP core network to respond to the variable demands of end
users. This new mechanism provides the operators a more efficient
resource utilization to support a larger number of IMS sessions in a
cost-effective manner.
Development of an
Open Source IMS Core for Emerging IMS Testbeds, the Academia and Beyond
(131-149)
D. Vingarzan, P.
Weik, and T. Magedanz
The IP Multimedia Subsystem (IMS) as defined by the 3GPP
emerges as blueprint for a central architecture to provide Next
Generation Network (NGN) services. As an overlay architecture for IP
based access networks, it provides standardized interfaces to services
which will merge the advantages of traditional telephony networks with
the benefits of Internet services. The {\it Open IMS Core}
project of the Fraunhofer Institute FOKUS which is described in this
article will start in 2006 as an Open Source initiative targeted at all
parties interested in the research development of NGN services and IMS
testbeds. The Open IMS Core consists of Call Session Control Functions
and a Home Subscriber Server and aims to fill the void in the Open
Source software landscape with flexible solutions that have proved their
conformance and performance in several national and international R\& D
projects. This article highlights the challenges in the
development of the components and provides insights on major
implementation details as well as for their performance. Examples of the
usage of the Open IMS Core will illustrate how IMS Open Source software
helps not only rapid, but also efficient, flexible and powerful design,
development and testing of NGN components and services.
Modeling IMS
services
(150-167)
E. Bertin, I. Ben Yahia, and
N. Crespi
The IMS offers telecom operators and service
providers with the architecture and the procedures to build an open
IP-based service infrastructure for deployment of innovative multimedia
communication services that integrate telecom and data services. IMS
services should be network agnostic and user-centric. This implies a
design of IMS services with reusable service enablers. This service
design should rely on a common IMS service modeling to ensure
interoperability and coherence in the service portfolio of service
providers. The article proposes a definition of IMS services and an IMS
service modeling that takes into account the user perception of the
service and the technical functions carrying out the service.
Resource Management
at Connection Level for Multimedia in Wireless/Mobile Cellular Networks
(168-178)
M. Sanabani,
S. Shamala, M. Othman, and Z. Zukarnain
Quality of Service (QoS)
guaranteed for multimedia services in next generation wireless/mobile
cellular networks poses great challenges due to the scarce radio
bandwidth. Therefore, the demand for effective and careful resource
allocation is immensely needed. In this paper, we combine Call Admission
Control (CAC) and Adaptive Resource Allocation (ARA) algorithm into a
novel framework, which we call Connection-Level Resource Controller (CLRC)
for provisioning connection-level QoS in Multimedia wireless/mobile
cellular networks. Simulation results show that the framework is able
to reduce Handoff Connection Dropping Probability (HCDP) for active
users of real time services to zero level. Thus, it satisfies mobile
users’ needs resulting in a stable performance levels during heavy load
periods. Furthermore, the framework provides a low New Connection
Blocking Probability (NCBP), which is translated into high resource
utilization. This is a highly desirable property from the service
provider point of view.
A Constraint-Based
Approach to Dynamically Adapt Multimedia Interfaces (179-196)
J.M. Oliveira and E.M.
Carrapatoso
The concept of the Virtual Home Environment~(VHE) was
introduced in mobile networks focusing on the issues surrounding the
support of non-standard services for roaming users. This paper presents
a proposal to solve the problem of the dynamic adaptation of multimedia
services provided by a telecommunications operator in the context of the
VHE concept. The paper discusses how the development of multimedia
services can be facilitated in this context, how these services can be
provided in a heterogeneous world of networks and terminals and how they
can be used in a personalized and adaptable way.} {The paper defines a
solution for the adaptation of multimedia services based on the
real-time generation of user interfaces conditioned by the user context.
The solution is mainly characterized by the approach used for resolving
the existing dependencies among user interface variables, which is based
on the constraints theory, and by the mechanism for acquiring the user
context information, which uses the Parlay/OSA interfaces.
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