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QoE – Based Scheduling in WiMAX Networks
Kalypso Magklara
1
, Aggeliki Sgora
1,3
, Dimitrios D. Vergados
1
and Dimitrios J. Vergados
2,3
1
Department of Informatics, University of Piraeus, 80, Karaoli & Dimitriou St., GR-185 34 Piraeus, Greece
2
National Technical University of Athens, School of Electrical & Computer Engineering,
GR 157 80 Zografou, Athens, Greece
3
Technological Educational Institute of Western Macedonia, Department of Informatics and Computer Technology
GR-52 100 Kastoria, Greece
Keywords: WiMAX, Networks, Scheduling, rtPS, Quality of Service (QoS), Quality of Experience (QoE).
Abstract: Worldwide Interoperability for Microwave Access (WiMAX) networks provide wireless broadband internet
access, interoperability, while decrease the entrance barrier in mobile communications sector, and offer
services comparable to those of the emerging 4G technology. Τhe standard 802.16, upon which WiMAX
networks are based, has not designated any particular scheduling algorithm, allowing each provider to
develop its own. However, existing scheduling algorithms take into account the Quality of Service (QoS),
fairness and other parameters, but do not provide Quality of Experience (QoE). For this reason, in this paper
two different approaches are proposed in order to provide QoE, especially for the rtPS WiMAX service.
Simulation results show that by applying different policies the QoE provided to the WiMAX users is
improved.
1 INTRODUCTION
Current trends and future projections of the traffic
patterns show that multimedia traffic will soon
represent the largest proportion of wireless
bandwidth, replacing voice and data traffic.
However, since existing legacy wireless
technologies where deployed to support only voice
and data, advanced wireless networking
technologies are essential for the provision of the
multimedia traffic, since its nature differs
fundamentally from voice and data.
WiMAX (Worldwide Interoperability for
Microwave Access) (IEEE Standard 802.16-2004) is
an emerging wireless access technology that
provides high data rates and differentiated services
based on individual QoS (Quality of Service)
requirements (Lee an Song, 2010). In general the
IEEE 802.16 standard specifies the Unsolicited
Grant Service (UGS) to support real-time service
flows that have fixed-size data packets on a periodic
basis, the real-time Polling Service (rtPS) to support
real-time service flows that generate variable data
packets size that are transmitted at fixed intervals,
the extended rtPS (ertPS) to support real-time
service flows that generate variable data packets size
on a periodic basis, the non real-time Polling Service
(nrtPS) to support non real-time service flows that
require variable size bursts on a regular basis, and
the Best Effort (BE) designed for traffic where no
throughput or delay guarantees are provided. Table 1
presents the WiMAX Services and their
representative examples, as well as, the QoS
specifications of each service.
However, since the multimedia applications
require interaction with the users, existing QoS
requirements and performance metrics such as jitter,
packet loss, throughput etc, cannot guarantee the
user‘s satisfaction. For that reason the service
providers are now switching from QoS to Quality of
Experience (QoE), a term that encompasses both
QoS and the overall user satisfaction, which is
defined subjectively for each application, according
to the users’ expectations. This creates the
opportunity for users, service providers and network
operators to take advantage of the varying
bandwidth and delay requirements, in order to
improve the aggregate QoE in the system, and at the
same time to limit the operating costs.
The contribution of this paper consists of the
application of QoE to WiMAX networks, where
each user has different subjective requirements of
the system in terms of quality of service. For this
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Magklara K., Sgora A., Vergados D. and Vergados D..
QoE – Based Scheduling in WiMAX Networks.
DOI: 10.5220/0004162103690373
In Proceedings of the International Conference on Signal Processing and Multimedia Applications and Wireless Information Networks and Systems
(WINSYS-2012), pages 369-373
ISBN: 978-989-8565-25-9
Copyright
c
2012 SCITEPRESS (Science and Technology Publications, Lda.)