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As we are moving forward to the 5G era, we are witnessing a transformation in the way networks are designed and behave, with the end-user placed at the epicenter of any decision. One of the most promising contributors towards this direction is the shift from Quality of Service (QoS) to Quality of Experience (QoE) service provisioning paradigms. QoE, i.e., the degree of delight or annoyance of a service as this is perceived by the end-user, paves the way for flexible service management and personalized quality monitoring. This is enabled by exploiting parametric QoE assessment models, namely specific formula-based QoE estimation methods. In this paper, recognizing a gap in the literature between the lack of a proper manual regarding the objective QoE estimation and the ever increasing interest from network stakeholders for QoE intelligence, we provide a comprehensive guide to standardized and state-of-the-art quality assessment models. More specifically, we identify and describe parametric QoE formulas for the most popular service types (i.e., VoIP, online video, video streaming, web browsing, Skype, IPTV and file download services), indicating the key performance indicators (KPIs) and major configuration parameters (MCPs) per type. Throughout the paper, it is revealed that KPIs and MCPs are highly variant per service type, and that, even for the same service, different factors contribute with a different weight on the perceived QoE. This finding can strongly enable a more meaningful resource provisioning across different applications compared to QoE-agnostic schemes. Overall, this paper is a stand-alone, self-contained repository of QoE assessment models for the most common applications, becoming a handy tutorial to parties interested in delving more into QoE network management topics.

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0163 6804/97/$10 00 © 1997 IEEE roadband and mobile communications are presently the two major drivers in the telecommunications industry. Asynchronous transfer mode (ATM) is considered the most suitable transport technique for the future broadband integrated services digital network (B-ISDN), due to its ability to flexibly support a wide range of services with qualityof-service (QoS) guarantees. On the other hand, wireless local area networks (LANs) are becoming popular for indoor data communications because of their tetherlessness and increasing transmission speed. Wireless communications have been developed to a level where offered services can now be extended beyond voice and data. The combination of wireless communications and ATM, especially in local-area environments, can provide freedom of mobility with service advantages and QoS guarantees. The main challenge of wireless ATM is to harmonize the development of broadband wireless systems with B-ISDN/ATM and ATM LANs, and offer similar advanced multimedia multiservice features for the support of time-sensitive voice communications, LAN data traffic, video, and desktop multimedia applications to the wireless user [1]. Emerging standards, such as High-Performance Radio LAN (HIPERLAN) or IEEE 802.11, have been designed to provide wireless access to corporate networks, but do not yet incorporate ATM technology over the air [2].There are several open issues in the development of wireless ATM. Most of them stem from the fact that ATM was designed with reliable fixed links in mind. More precisely, ATM assumes fixed users, plentiful and constant bandwidth allocated dynamically based on users' needs, full duplex and point-to-point transmission, very good transmission quality (which is why error detection and error correction techniques are limited), and low physical-layer overhead. On the other hand, in a wireless environment users can move inside the covered range, the available bandwidth in the radio interface is limited and can vary based on the quality of the channel, transmission is usually half duplex and point-to-multipoint due to the lack of available frequencies, transmission quality is usually poor requiring advanced error detection and error correction techniques, and physical overhead is much higher than in fixed links, basically due to the synchronization delay between transmitter and receiver [3].Currently, a number of research activities are focusing on the topic of wireless ATM to resolve its problems (e.g., [4][5][6][7]). One of these activities is project Magic WAND (Wireless ATM Network Demonstrator) [8], which is investigating wireless ATM technology for customer premises networks in the framework of the Advanced Communications Technologies and Services (ACTS) program funded by the European Union. The main components of the WAND system, as shown in Fig. 1, are:• Mobile terminals (MTs), the end-user equipment, which are basically ATM terminals with a radio adapter card • Access points (APs), the base stations of the cellular environment • An ATM ...