Defining and Assessing Quality in IoT Environments: A Survey

With the proliferation of multimedia services, Quality of Experience (QoE) has gained a lot of attention. QoE ties together the users’ needs and expectations to multimedia application and network performance. However, in various Internet of Things (IoT) applications such as healthcare, surveillance systems, traffic monitoring, etc., human feedback can be limited or infeasible. Moreover, for immersive augmented and virtual reality, as well as other mulsemedia applications, the evaluation in terms of quality cannot only focus on the sight and hearing senses. Therefore, the traditional QoE definition and approaches for evaluating multimedia services might not be suitable for the IoT paradigm, and more quality metrics are required in order to evaluate the quality in IoT. In this paper, we review existing quality definitions, quality influence factors (IFs) and assessment approaches for IoT. This paper also introduces challenges in the area of quality assessment for the IoT paradigm

QoS provision and resource allocation in modern wireless networks

The main goal of the current wireless networks is the support for multimedia services, such as voice application, video on demand, data and image transmission. However, in order to support such a wide range of traffic, Quality of Service (QoS) has to be taken into consideration. The topic of this PhD thesis is the development of mechanisms for resource allocation and QoS provision in the modern wireless networks. More specifically, during the elaboration of this thesis several methods were studied for the better exploitation of the radio, such as resource allocation mechanisms for the optimal and fair resource allocation depending on the users’ preferred service, factors that influence the network performance, such the phenomenon of the handoff in a wireless cellular network, and metrics that evaluate the performance of these networks, such as the delay and the jitter.Βασικός στόχος των σύγχρονων ασύρματων δικτύων είναι η υποστήριξη εφαρμογών πολυμεσικής κίνησης, όπως για παράδειγμα εφαρμογές φωνής, βίντεο σύμφωνα με τη ζήτηση, δεδομένα και εικόνα. Όμως, η παροχή αυτών των υπηρεσιών στο ασύρματο περιβάλλον συνεπάγεται την άμεση ανάγκη για παροχή εγγυημένης ποιότητας υπηρεσίας σε σύγχρονα ασύρματα δίκτυα. Αντικείμενο της παρούσης διατριβής ήταν ο σχεδιασμός μηχανισμών για την διαχείριση και κατανομή πόρων και για την παροχή ποιότητας υπηρεσίας σε σύγχρονα ασύρματα δίκτυα. Ειδικότερα στα πλαίσια της εκπόνησης της παρούσης διατριβής μελετήθηκαν τρόποι για την καλύτερη αξιοποίηση του ραδιοφάσματος, όπως τρόποι κατανομής και διαχείρισης των πόρων του δικτύων για τη βέλτιστη και δίκαιη κατανομή των πόρων στους χρήστες ανάλογα με την υπηρεσία που αυτοί επιλέγουν. Επίσης μελετήθηκαν παράγοντες που επηρεάζουν την επίδοση ενός δικτύου, όπως το φαινόμενο της διαπομπής σε ένα κυψελοειδές δίκτυο, καθώς και τις μετρικές που αξιολογούν την επίδοση ενός δικτύου, όπως η καθυστέρηση και η διακύμανση

A survey of TDMA scheduling schemes in wireless multihop networks

One of the major problems in wireless multihop networks is the scheduling of transmissions in a fair and efficient manner. Time Division Multiple Access (TDMA) seems to be one of the dominant solutions to achieve this goal since it is a simple scheme and can prolong the devices’ lifetime by allowing them to transmit only a portion of the time during conversation. For that reason, several TDMA scheduling algorithms may be found in the literature. The scope of this article is to classify the existing TDMA scheduling algorithms based on several factors, such as the entity that is scheduled, the network topology information that is needed to produce or maintain the schedule, and the entity or entities that perform the computation that produces and maintains the schedules, and to discuss the advantages and disadvantages of each category.</jats:p

An autonomous QoE-driven network management framework

Recently, network researchers have taken a great interest in quality of experience (QoE) and in the new aspects it brings in the study of the link between network conditions and user satisfaction. Also, the realization that the information of users' satisfaction can be directly applied in the network management in a real-time manner has resulted in a fair amount of publications. Although the systems and frameworks presented in these publications tackle the subject of QoE-driven management quite successfully, they often concentrate on certain applications or technologies. We present a generic QoE management framework, which is applicable to a broad range of systems. We also demonstrate an instantiation of this framework as a network access point management system for RTP-based video. This system is not only able to positively affect the perceived quality of the multimedia application considered, but also to reduce over-prioritization and optimize resource usag