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Received Nov 9, 2017; Accepted Jan 22, 2018
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1. Introduction
Internet Protocol Television (IPTV) services [1] have been becoming increasingly popular among telecommunication companies. Network/service providers are concerned with not only the cost of constructing an IPTV service system [2] but also its service quality [3, 4]. In the past, Quality of Service (QoS) of network services is the main concern. However, QoS cannot accurately characterize the users’ perception. Therefore, the concept of Quality of Experience (QoE) was proposed and studied recently [5–13].
The most accurate method to obtain QoE is doing subjective tests [14] that are time-consuming and costly. Therefore, we proposed a cost-effective and real-time QoE evaluation method in [5], where a hybrid QoE assessment scheme was employed. In the hybrid QoE assessment, subjective tests only need be performed occasionally for updating the parameters of QoS-QoE mapping functions. Hence, the cost of a hybrid QoE assessment scheme reduces significantly. In [7], the QoE measurement for P2P-based IPTV services was studied. Another paper [8] proposed a QoS/QoE mapping and adjustment model for the cloud-based multimedia infrastructure. Additionally, since streaming services over wireless networks have been becoming popular, the QoE enhancement algorithms, protocols, and evaluation methods for wireless streaming services were proposed [9–12]. In [13], Chen et al. presented a comprehensive survey of the evolution of video quality assessment methods and analyzed their characteristics, advantages, and drawbacks.
Since the QoE evaluation for streaming services becomes more and more important, several QoE evaluation or monitoring tools were developed [15–19]. A QoE monitoring tool for multimedia quality assessment in NS-3 network simulator was presented in [15]. However, since the objective and full-reference QoE assessment method is used in [15], it is costly and cannot accurately indicate the users’ perception in a real commercial video streaming system. The paper [16] developed a testbed, which allows obtaining conclusive results regarding QoE in video-mediated group communication, for controlled experiments. In [17], Jeong and Ahn designed the QoE monitoring function for video services by extending ITU-T IPTV QoS/QoE metrics and integrating to OMA-DM protocol agent. Although the monitoring service can improve...