Joint Use of On-board Reconfigurable Antenna Pattern and Adaptive Coding and Modulation in Satellite Communications at High Frequency Bands

The Telecommunication market is driven by the increasing need of the end users for multimedia services which require high data rates. Within the fixed satellite service, frequency bandwidths wide enough to carry such high data rates are to be found in Ka band (26-40 GHz), and Q/V bands (40-50 GHz). However, at Ka band and above, transmitted signals can be severely affected by tropospheric attenuation for substantial percentages of time, resulting in the degradation of the quality and of the availability of communication services. Fade Mitigation Techniques (FMTs) must be used to counteract these severe propagation impairments. In this thesis we explore the joint use of two of the most promising techniques, known as Reconfigurable Antenna and Adaptive Coding and Modulation, which up to now has been separately developed. Some of our accomplishments include, but are not limited to: a methodology to describe rain attenuation conditions for multiple users in large geographical areas, a tractable framework for the generation of correlated time series of rain attenuation for multiple receiving stations, the comparison of performance between fixed antenna systems and Reconfigurable Antenna system coupled with Adaptive Coding and Modulation

Cross-Layer Optimization of Network Performance over MIMO Wireless Mobile Channels

In the information theory, the channel capacity states the maximum amount of information which can be reliably transmitted over the communication channel. In the specific case of multiple-input multiple-output (MIMO) wireless systems, it is well recognized that the instantaneous capacity of MIMO systems is a random Gaussian process. Time variation of the capacity leads to the outages at instances when it falls below the transmission rate. The frequency of such events is known as outage probability. The cross-layer approach proposed in this work focuses on the effects of MIMO capacity outages on the network performance, providing a joint optimization of the MIMO communication system. For a constant rate transmission, the outage probability sensibly affects the amount of information correctly received at destination. Theoretically, the limit of the ergodic capacity in MIMO time-variant channels can be achieved by adapting the transmission rate to the capacity variation. With an accurate channel state information, the capacity evolution can be predicted by a suitable autoregressive model based on the capacity time correlation. Taking into consideration the joint effects of channel outage at the physical layer and buffer overflow at the medium access control (MAC) layer, the optimal transmission strategy is derived analytically through the Markov decision processes (MDP) theory. The adaptive policy obtained by MDP is optimal and maximizes the amount of information correctly received at the destination MAC layer (throughput of the system). Analytical results demonstrate the significant improvements of the optimal variable rate strategy compared to a constant transmission rate strategy, in terms of both system throughput and probability of data loss

Milestone M5.8 KRSM first cycle prototype evaluation plan

This plan will be constantly updated and expanded in line with the planned software development activities related to the KRSM component of the TENCompetence infrastructure.This report provides a detailed plan for experimentation and evaluation of the KRSM prototype.The work on this publication has been sponsored by the TENCompetence Integrated Project that is funded by the European Commission's 6th Framework Programme, priority IST/Technology Enhanced Learning. Contract 027087 [http://www.tencompetence.org

ID2.1 Initial Requirements Report

This internal deliverable contains two main parts: 1. Functional Requirements for the TENCompetence integrated system (which includes the descriptions of the high level use cases and the main components of the system) 2. Non Functional Requirements for the TENCompetence inte-grated systemThe work on this publication has been sponsored by the TENCompetence Integrated Project that is funded by the European Commission's 6th Framework Programme, priority IST/Technology Enhanced Learning. Contract 027087 [http://www.tencompetence.org

Guidelines for an effective design of serious games

There is an increasing awareness about the potential of serious games for education and training in many disciplines. However, research still witnesses a lack of methodologies, guidelines and best practices on how to develop effective serious games and how to integrate them in the actual learning and training processes. The process of integration heavily depends on providing and spreading evidence of the effectiveness of serious games. In this paper we present an overview on the factors that make serious games effective in the perspective of maximizing the learning impact. Such recommendations are the result of an extensive survey of the current proposition of serious games in different application domains

Designing Collaborative Learning and Innovation Systems for Education Professionals

Angehrn, A. A., Maxwell, K., Luccini, A. M., & Rajola, F. (2008). Designing Collaborative Learning and Innovation Systems for Education Professionals. In M. D. Lytras, J. M. Carroll, E. Damiani & R. D. Tennyson (Eds.), Proceedings of the 1st World Summit on the Knowledge Society: Emerging Technologies and Information Systems for the Knowledge Society (pp. 167-176). September, 24-26, 2008, Athens, Greece: Lecture Notes in Artificial Intelligence, vol. 5288, Springer-Verlag, Berlin, Heidelberg.Designing online systems to stimulate and support knowledge exchange, collaborative learning and innovation in distributed communities of professionals is a challenging task. In this paper we document the design of CMTube, a system aimed at stimulating and supporting value-adding online interactions among a distributed group of independent higher education professionals using the same learning approach, i.e., a management simulation. CMTube is based on latest web trends and makes extensive use of video, profiling, game dynamics, agents and network visualizations in order to capture the attention and involvement of community members by generating three different types of value: connection value, actionable learning value, as well as entertainment and instant gratification value. We also discuss the assessment of these different value dimensions, as well as ongoing and planned research directions.The work on this publication has been sponsored by the TENCompetence Integrated Project that is funded by the European Commission's 6th Framework Programme, priority IST/Technology Enhanced Learning. Contract 027087 [http://www.tencompetence.org

Assessment of rain fade mitigation techniques for high throughput satellites by a time series synthesizer

We assess here the effectiveness of fade mitigation techniques on the user link side of a TLC satellite system by a simulation tool able to generate correlated time series of rain attenuation in multiple sites. A preliminary analysis of two case studies shows that on-board dynamic power allocation coupled with ACM reduces the impact of heavy fades, permits a larger exploitation of efficient MODCODs and equalizes the performance of the user links. However, in the presence of convective cells, co-channel interference can be dominant, hence reducing the benefits of the above techniques