The assurance of quality of experience (QoE) and provisioning of high throughput of the system represent the main goals of future wireless and mobile networks. This paper presents novel and practical crosslayer QoEaware radio resource allocation (RRA) algorithms for the downlink of a heterogeneous orthogonal frequency division multiple access (OFDMA) system. The objective of the proposed algorithms is to assure the appropriate level of QoE for each user of the system by incorporating applicationlayer parameters and subjective human perception of quality into the RRA process. We propose two useroriented joint subcarrier and power allocation algorithms with low complexity for realtime and interactive services. The first algorithm dynamically allocates resources by assuring the same level of QoE to all users of the system, whereas the second algorithm introduces the efficient tradeoff between the user's QoE and the spectral efficiency of the system. By considering applicationlayer parameters and user's perception of quality, high users' QoE and explicit control of data rates can be achieved. The numerical results show that the proposed algorithms achieve significant increase in the level of QoE compared to previous works, a fair distribution of capacity among users and near to optimal solution of QoE for the OFDMA system.
This paper presents results of an experimental study focused on predictive modeling of the relations between the user perception, user satisfaction and objective technical parameters in data communication services. A new model for prediction of user satisfaction was devised using probability theory based on Markov chain. Two experiments were completed for web browsing scenarios, confirming that previous user experience has significant effect on the user perception of quality and should represent a vital element of future predictive user models. This model can significantly improve level of user satisfaction with services in telecommunications systems if implemented within advanced system design, optimization and quality assurance procedures.
The paper describes the architecture and design of an IPTV network monitoring system and some of the use cases it enables. The system is based on distributed agents within IPTV terminal equipment (Set-top box), which collect and send the data to a server where it is analyzed and visualized. In the paper we explore how large amounts of collected data can be utilized for monitoring the quality of service and user experience in real-time, as well as for discovering trends and anomalies over longer periods of time. Furthermore, the data can be enriched using external data sources, providing a deeper understanding of the system by discovering correlations with events outside of the monitored domain. Four supported use cases are described, among them using weather information for explaining away the IPTV quality degradation. The system has been successfully deployed and is in operation at the Slovenian IPTV provider Telekom Slovenije.
Modern multimedia communications networks are required to provide end-to-end quality assurance by equally assuming both quality of service (QoS) and quality of experience (QoE). In the article, an IMS service enabler is proposed that provides intelligent QoE control into the service chain based on reuse of strictly standardized existent NGN/IMS, RACS and NASS technologies, protocols and procedures. QoE control is achieved through service intelligence that collects available data on end users, services, contents and communication chain, their interpretation using objective QoE models, and appropriate proactive actions for profile and configuration modifications to achieve enhanced QoE and QoS conditions. Results of pilot implementation are given in laboratory environment, presenting QoE controller operation and its effects on the achieved quality of experience for a multimedia communication case.
A proposal of novel generic QoS and QoE models for convergent multimedia communications environments. Simulation results of objective QoE modelling in standardized NGN environment with IMS, RACS and NASS subsystems are presented. Technical and commercial success of professional operator services in NGN networks using Internet model are conditioned with ability to provide appropriate quality of the communication compared to best effort services in the Internet. Herewith, in case of modern dynamic and interactive multimedia-rich services the importance of achieved Quality of Experience (QoE) equals or exceeds importance of Quality of Service (QoS). This area of research is of substantial importance according to relevant scientific literature; however, today there is indigence in appropriate standards, recommendations and research results that would serve for direct application into realworld environments. The article presents results of detailed analysis on QoE and QoS profiling on all communication layers and presents modelling and simulations of QoE in NGN network using IMS, RACS and NASS subsystems. The presented results and findings are compliant with existent standards and recommendations for objective endtoend modelling. Presented models are based exclusively on existent profiles, functionalities, procedures and protocols available in an NGN.