Enhancing the Performance of Low Priority SUs Using Reserved Channels in CRN

Cognitive radio networks (CRNs) are considered a promising solution for spectrum resources scarcity and efficient channel utilization. In this letter, multi-dimensional analytical Markov model based on reservation channel access scheme and channel aggregation method is proposed to enhance spectrum utilization, capacity of low priority secondary users (SUs) and reducing handoff probability of SUs. Moreover, the proposed method improves the performance of high priority SUs by providing the capability to resume the connection after dropping. The numerical results indicate that the modified reservation access model can enhance the performance of SUs compared to the traditional basic random access model

Cognition-inspired 5G cellular networks: a review and the road ahead

Despite the evolution of cellular networks, spectrum scarcity and the lack of intelligent and autonomous capabilities remain a cause for concern. These problems have resulted in low network capacity, high signaling overhead, inefficient data forwarding, and low scalability, which are expected to persist as the stumbling blocks to deploy, support and scale next-generation applications, including smart city and virtual reality. Fifth-generation (5G) cellular networking, along with its salient operational characteristics - including the cognitive and cooperative capabilities, network virtualization, and traffic offload - can address these limitations to cater to future scenarios characterized by highly heterogeneous, ultra-dense, and highly variable environments. Cognitive radio (CR) and cognition cycle (CC) are key enabling technologies for 5G. CR enables nodes to explore and use underutilized licensed channels; while CC has been embedded in CR nodes to learn new knowledge and adapt to network dynamics. CR and CC have brought advantages to a cognition-inspired 5G cellular network, including addressing the spectrum scarcity problem, promoting interoperation among heterogeneous entities, and providing intelligence and autonomous capabilities to support 5G core operations, such as smart beamforming. In this paper, we present the attributes of 5G and existing state of the art focusing on how CR and CC have been adopted in 5G to provide spectral efficiency, energy efficiency, improved quality of service and experience, and cost efficiency. This main contribution of this paper is to complement recent work by focusing on the networking aspect of CR and CC applied to 5G due to the urgent need to investigate, as well as to further enhance, CR and CC as core mechanisms to support 5G. This paper is aspired to establish a foundation and to spark new research interest in this topic. Open research opportunities and platform implementation are also presented to stimulate new research initiatives in this exciting area

SDNと車両クラスタリングを活用したV2I通信方式

電気通信大学202

A survey on Quality of Experience of Virtual and Augmented Reality environments

Οι εφαρμογές εικονικής και επαυξημένης πραγματικότητας αποτελούν μια νέα και πολλά υποσχόμενη τεχνολογία, με εφαρμογές στην ιατρική, την εκπαίδευση, τα βιντεοπαιχνίδια, το ηλεκτρονικό εμπόριο και πολλές άλλες. Αυτή η τεχνολογία θέτει μια νέα πρόκληση για τους σχεδιαστές εφαρμογών, καθώς και για τους παρόχους υπηρεσιών δικτύου, επειδή είναι εντατική ως προς τους απαιτούμενους πόρους ώστε να είναι σε θέση να παρέχει συναρπαστική εμπειρία στους χρήστες της. Αυτή η πρόκληση γίνεται ακόμη πιο δύσκολη στα δίκτυα κινητής τηλεφωνίας, λόγω παραγόντων που είναι δύσκολο να μοντελοποιηθούν και να προβλεφθούν, όπως η κινητικότητα, η στρατηγική μεταβίβασης και η κατανομή πόρων. Αυτή η διπλωματική φιλοδοξεί να παράσχει μια ανασκόπηση των τεχνικών και μεθόδων εκτίμησης της ποιότητας της εμπειρίας (QoE) και των μεθόδων που έχουν αναπτυχθεί γύρω από αυτές τις εφαρμογές. Στην πρώτη ενότητα, εξετάζουμε τις στρατηγικές παροχής QoE για εφαρμογές εικονικής πραγματικότητας. Αυτή η ενότητα εξετάζει αρκετές περιπτώσεις εφαρμογών εικονικής πραγματικότητας, όπως ένα λογισμικό προσομοίωσης βαρέων μηχανημάτων, μια εκπαιδευτική εφαρμογή και άλλες ψηφιακές εφαρμογές εμβύθισης. Το εύρος και η ποικιλία των εφαρμογών και των μεθόδων εκτίμησης της ποιότητας της εμπειρίας οδηγούν σε αντικρουόμενα συμπεράσματα σχετικά με τις μεθόδους αξιολόγησης QoE. Στην επόμενη ενότητα αναφερόμαστε σε εφαρμογές επαυξημένης πραγματικότητας, και πάλι με μια αναφορά σε μια μεγάλη ποικιλία εφαρμογών, όπως ένας βοηθός επαυξημένης πραγματικότητας, βιντεοπαιχνίδια επαυξημένης πραγματικότητας και άλλες ψηφιακές εφαρμογές. Τα συμπεράσματα σε αυτήν την ενότητα είναι πιο ισχυρά και τα συναισθήματα των ανθρώπων μπορούν να σχηματίσουν πιο ουσιαστικά πορίσματα. Στην τελευταία ενότητα διερευνούμε την QoE σε εφαρμογές εικονικής και επαυξημένης πραγματικότητας για κινητές συσκευές και κινητά δίκτυα. Σε αυτό το μέρος ασχολούμαστε με πιο τεχνικές πτυχές όπως η διαχείριση της κινητικότητας, οι στρατηγικές μεταβίβασης και οι αλγόριθμοι κατανομής πόρων και ο αντίκτυπος που έχουν αυτοί στην εμπειρία των χρηστών.Virtual and augmented reality applications constitute a new and promising technology, with applications in medicine, education, gaming, e-commerce and many more. This technology poses a new challenge to application designers, as well as network service providers, because it is resource intensive in order to be able to provide the immersive experience to its users. This task becomes even more challenging in mobile networks, due to factors that are difficult to be modeled and predicted, such as mobility, handoff strategy and resource allocation. This thesis aspires to provide a review of Quality of Experience (QoE) estimation and provision techniques and methods that have been developed around these applications. In the first section, we review QoE provisioning strategies for virtual reality applications. This section examines some corner cases of augmented reality applications, such as a heavy machinery simulation software, an educational application, and many digital immersive applications. The scope and diversity of applications and implementation methods lead to some conflicting conclusions in relation to QoE evaluation methods. In the next section we refer to augmented reality applications, again with a reference to a wide variety of applications such as an augmented reality task assistant, augmented reality video games and digital immersive applications. The conclusions in this section are more robust and peoples’ feelings can form more meaningful aggregations. In the last section we investigate the QoE in virtual and augmented reality applications when these applications are implemented in mobile devices. Τhis part is concerned with more technical aspects such as mobility management, handoff strategies and resource allocation algorithms and their impact on users’ experience

A QoE-driven Vertical Handover Management Framework for Multimedia Services over Wireless Networks

With advances in wireless technology and mobile devices, the number of mobile users using multimedia services has increased significantly in recent years. Mobile devices can be connected and roam on heterogeneous wireless networks. The IEEE 802.21 group has designed a Media Independent Handover (MIH) standard to ensure seamless Vertical Handover (VHO) in heterogeneous networks. However, the standard currently depends on features of the network (e.g. the type of network and available bandwidth) to achieve seamless VHO. This approach is limited, as it does not consider how a Quality of Experience (QoE) can be provided and maintained for customers when delivering multimedia services in heterogeneous wireless networks. The aim of the project is to develop a novel QoE-driven VHO management framework for providing and maintaining an appropriate level of QoE of multimedia services as the mobile user’s actual requirements in heterogeneous wireless networks. A QoE-driven VHO algorithm is more efficient for maintaining this acceptable QoE of multimedia services than traditional network-based or QoS-based VHO algorithms. There are three main contributions during this project. Firstly, A thorough evaluation of the performance of voice and video services via Skype was carried out in terms of the QoE metric (i.e. MOS). This work identified the impact of video content and packet loss on the QoE metric for voice and video communication services over wireless networks. Secondly, a QoE-driven VHO algorithm was developed to provide and maintain an acceptable QoE of mobile video services for mobile users. Compared to a traditional network-based VHO algorithm, this algorithm can provide better QoE and maintain acceptable QoE. Lastly, the User-centric QoE-driven (UCQoE) VHO framework to provide satisfactory QoE of multimedia services according to the mobile user’s requirements. The framework allows users to set their own preferences (e.g. quality-guarantee or cost-free) and carry out VHO operations accordingly. The evaluation showed that the proposed framework can provide a better QoE for delivered video services than QoS-based and network-based VHO algorithms. Furthermore, the proposed framework can be used to avoid unnecessary cost of mobile data when the option of cost-free is preferred by the user. During this project, three international conference papers had been published and a journal paper has been submitted to IEEE Transactions on Mobile Computing. The main contribution-UCQoE VHO management framework can be developed to maintain QoE of all mobile services in the future