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Item type:Publication, Access status: with files , A two-game algorithm for device-to-device resource allocation with frequency reuseNext generation mobile systems aim to meet the strict demands of an exponentially increasing number of users. Particularly device-to-device (D2D) communication has attracted a lot of attention during the last years. D2D communication can ofïoad cellular trafïc off the base station. It may reuse radio frequency resources simultaneously used by cellular communication for D2D transmissions, thereby increasing spectral efïciency and system capacity. However, reusing frequency resources can lead to in-cell interference. The expected interference must therefore be actively mitigated as part of the scheduling process. We investigate a novel joint radio resource scheduling and allocation algorithm for D2D communication that makes use of two methods from the ïeld of game theory. It aims to meet the respective userâ™s Quality of Service requirements and strives for fairness between users by playing a Transferable Utility game. At the same time it actively mitigates in-cell interference from frequency resource reuse and determines an optimal transmission power through Stackelberg gameplays. It is shown through simulation that system performance increases if resource allocation and reuse is done in a coordinated manner. The proposed scheduler scales well due to its polynomial computational complexity and outperforms baseline schedulers and the single-game approach in several simulated scenarios.Publicationtype: Conference PaperScopus© Citations 3 284 331 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Rare event analysis using the Limited Relative Error algorithm for OMNeT++ simulationsThe Limited Relative Error algorithm is an alternative statistical method for data evaluation. Through online result analysis it continuously requests more samples until it deems the evaluation confident enough. With this it allows researchers to hand over the control of simulation time to the algorithm, and through a-priori configuration the target result resolution is set so that arbitrarily rare events can be investigated. We provide a new description of the method as well as a stand-alone implementation and an integration of the algorithm into the OMNeT++ simulator.Publicationtype: Conference Paper338 502 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Teaching Modelling and Analysis of Communication Networks using OMNeT++ Simulator(2018-10-23); ; ; ; At the Hamburg University of Technology, Germany, the modelling of communication networks using the OMNeT++ simulator and the INET framework is taught for Master students. Teaching the concepts of simulation and modelling while letting the students obtain a hands-on experience during a 14-week (4h/week) period (single semester) is a challenging task. The diversity of the pre-knowledge of the participating students and the duration of the course are the main challenges that need to be addressed when organising such a course. This paper discusses the structure of this course and the best practices followed. The course adopts a methodology where lectures on concepts are mixed with INET based exercises that begin with simple topics and gradually moving into advanced topics.Publicationtype: Conference Paper476 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Learning management systems on blended learning courses : an experience-based observationThis paper gives an overview of Learning Management System (LMS) features based on observations on a blended learning course under the Erasmus+ project COLIBRI. We explain the main features of LMSes under two main categories: accessibility content-related and underline the capabilities of four LMSes, Moodle, Blackboard Learn, Canvas, and Stud.IP with respect to these. We explain how these features were utilized to increase the efficiency, tractability, and quality of experience of the course. We found that an LMS with advanced features such as progress tracking, modular course support, interactive content support, and content access restriction is of paramount importance for blended learning courses.Publicationtype: Conference Paper243 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , International student projects in a blended setting: How to facilitate problem based project workThis paper describes our experiences with facilitating international student projects during three years of the Erasmus+ Strategic Partnership COLIBRI (Collaboration and Innovation for Better, Personalized and IT-Supported Teaching). Each year 7-8 student projects were carried out in groups of 3-5 students from different European universities, with different backgrounds from business and engineering. Each year new students were selected for participation. The student projects carried out were based on real-life problems from companies, and each group was assigned both an academic supervisor from one of the seven participating universities and an academic supervisor from one of the three participating companies. The projects were based on a combination of physical mobility and virtual mobility: The students would meet for one week at the beginning of the project work, then work together virtually for around 2-3 months, and then meet again for a week where the projects were finalised and evaluated. This setup is challenging: The students do not know each other beforehand, most of the students are not familiar with problem based projects and collaboration with industry, the students represent both different educational traditions and disciplines, and the virtual collaboration is by itself challenging. The project was carried out in three cycles, where for each cycle we systematically evaluated the previous experience and adapted our approach to e.g. project descriptions, seminar organisations, elements to support the students in the project work, and project supervision. Based on our evaluations, we see that each year student satisfaction was increased, and at the same time both companies and students reported improved learning outcome and project results. The last year a survey was made for the students to evaluate the support from different elements such as online modules, introduction to project work, instructions of expected outcome, templates, and supervision during both physical and virtual collaboration phases. We conclude that such international and interdisciplinary projects can be very rewarding, but also that careful planning and implementation is needed to achieve the full potential. © 2018, University of Minho.Publicationtype: Conference Paper126 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Optimising LTE uplink scheduling by solving the multidimensional assignment problemInter-cell interference mitigation in LTE networks is important to improve the system throughput. Upcoming Cloud Radio Access Networks (C-RANs) allow controlling multiple cells at a single location enabling novel inter-cell coordination algorithms. Coordinated recourse allocation can be used to achieve optimal spectral efficiency through reduced inter-cell interference. In this paper the uplink resource allocation is optimised by deciding which user terminals served by different base stations should transmit on the same resources. A central meta-scheduler situated in the cloud is responsible for the optimisation. The optimisation is performed using heuristic algorithms to solve the underlying multidimensional assignment problem. The complexity is further reduced to a feasible size by only coordinating a subset of base stations. This way the problem can be solved for real world cellular deployments. The performance for different groupings of cooperatively managed base stations is investigated. Results show that coordinating resource assignment of multiple base stations improves the cell spectral efficiency in general and coordinating three sectors at the same site outperforms coordinating three base stations of different sites.Publicationtype: Conference Paper154 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Optimal uplink scheduling for device-to-device communication with mode selectionDevice-to-Device communication is discussed for future mobile communication systems. In this work, an upper bound capacity limit is determined for a mobile communication system consisting of Device-to-Device and cellular users is determined. Therefore, we formulate the problem as a linear program and solve it optimally. The potential of Device-to-Device communication is evaluated using a distance based mode selection scheme. It is shown that the amount of traditional cellular users is influencing the optimal distance for using Device-to-Device communication instead of traditional cellular transmission. The optimisation potential is then analysed for a different amount of users and cell sizes.Publicationtype: Conference Paper149