Report on the 6th ADBIS’2002 conference

The 6th East European Conference ADBIS 2002 was held on September~8--11, 2002 in Bratislava, Slovakia. It was organised by the Slovak University of Technology (and, in particular, its Faculty of Electrical Engineering and Information Technology) in Bratislava in co-operation with the ACM SIGMOD, the Moscow ACM SIGMOD Chapter, and Slovak Society for Computer Science. The call for papers attracted 115 submissions from 35~countries. The international program committee, consisting of 43 researchers from 21 countries, selected 25 full papers and 4 short papers for a monograph volume published by the Springer Verlag. Beside those 29 regular papers, the volume includes also 3 invited papers presented at the Conference as invited lectures. Additionally, 20 papers have been selected for the Research communications volume. The authors of accepted papers come from 22~countries of 4 continents, indicating the truly international recognition of the ADBIS conference series. The conference had 104 registered participants from 22~countries and included invited lectures, tutorials, and regular sessions. This report describes the goals of the conference and summarizes the issues discussed during the sessions

Delivery of broadband services to SubSaharan Africa via Nigerian communications satellite

Africa is the least wired continent in the world in terms of robust telecommunications infrastructure and systems to cater for its more than one billion people. African nations are mostly still in the early stages of Information Communications Technology (ICT) development as verified by the relatively low ICT Development Index (IDI) values of all countries in the African region. In developing nations, mobile broadband subscriptions and penetration between 2000-2009 was increasingly more popular than fixed broadband subscriptions. To achieve the goal of universal access, with rapid implementation of ICT infrastructure to complement the sparsely distributed terrestrial networks in the hinterlands and leveraging the adequate submarine cables along the African coastline, African nations and their stakeholders are promoting and implementing Communication Satellite systems, particularly in Nigeria, to help bridge the digital hiatus. This paper examines the effectiveness of communication satellites in delivering broadband-based services

Optimal channel allocation with dynamic power control in cellular networks

Techniques for channel allocation in cellular networks have been an area of intense research interest for many years. An efficient channel allocation scheme can significantly reduce call-blocking and calldropping probabilities. Another important issue is to effectively manage the power requirements for communication. An efficient power control strategy leads to reduced power consumption and improved signal quality. In this paper, we present a novel integer linear program (ILP) formulation that jointly optimizes channel allocation and power control for incoming calls, based on the carrier-to-interference ratio (CIR). In our approach we use a hybrid channel assignment scheme, where an incoming call is admitted only if a suitable channel is found such that the CIR of all ongoing calls on that channel, as well as that of the new call, will be above a specified value. Our formulation also guarantees that the overall power requirement for the selected channel will be minimized as much as possible and that no ongoing calls will be dropped as a result of admitting the new call. We have run simulations on a benchmark 49 cell environment with 70 channels to investigate the effect of different parameters such as the desired CIR. The results indicate that our approach leads to significant improvements over existing techniques.Comment: 11 page

Cross-layer scheduling and resource allocation for heterogeneous traffic in 3G LTE

3G long term evolution (LTE) introduces stringent needs in order to provide different kinds of traffic with Quality of Service (QoS) characteristics. The major problem with this nature of LTE is that it does not have any paradigm scheduling algorithm that will ideally control the assignment of resources which in turn will improve the user satisfaction. This has become an open subject and different scheduling algorithms have been proposed which are quite challenging and complex. To address this issue, in this paper, we investigate how our proposed algorithm improves the user satisfaction for heterogeneous traffic, that is, best-effort traffic such as file transfer protocol (FTP) and real-time traffic such as voice over internet protocol (VoIP). Our proposed algorithm is formulated using the cross-layer technique. The goal of our proposed algorithm is to maximize the expected total user satisfaction (total-utility) under different constraints. We compared our proposed algorithm with proportional fair (PF), exponential proportional fair (EXP-PF), and U-delay. Using simulations, our proposed algorithm improved the performance of real-time traffic based on throughput, VoIP delay, and VoIP packet loss ratio metrics while PF improved the performance of best-effort traffic based on FTP traffic received, FTP packet loss ratio, and FTP throughput metrics