Optimization of GEO Satellite Links Deployment in the Internet

As the satellite technology will be one of the main components of the Next Generation Internet (NGI), a naturally occurring question concerns the feasibility of providing an optimal satellite-based Internet access. In this paper, we are interested in GEO satellite links deployment in the Internet by addressing the problem of terrestrial-satellite hybrid network optimization for which we propose a general architecture. We devide the general optimization problem into several sub-problems which can be resolved separately. Each sub-problem treats a specific type of traffic and it is defined by a set of inputs, variables, goals, and constraints. The global GEO satellite links deployment optimization heuristic that we propose attempts to determine the optimal hybrid topology which minimizes performance metrics such as delay, throughput, call blocking probabilities, and network cost. Two main steps compose the proposed heuristic: performance evaluation step and satellite uplink position finding step. During the first step we try to determine values of performance metrics of studied traffic and in the second one, we look for the optimal position where to add the current satellite uplink in order to optimize performance criteria. We present in details a case study dealing with multicast traffic optimization during the deployment of GEO satellite links in the Internet. We develop a configuration policy of PIM-SM in hybrid networks concerning the choice of the list of Rendezvous Point (RPs) and the switching from the RP-routed tree to the shortest path tree. This policy provides an optimal use of satellite links for multicast transfer. The obtained results demonstrate the ability of the proposed optimization method to improve multicast performan- ce criteria and to determine effectively satellite uplinks positions using PIM-SM combined with UDLR (UniDirectional Link Routing)

iTETRIS: An Integrated Wireless and Traffic Platform for Real-Time Road Traffic Management Solutions

Wireless vehicular cooperative systems have been identified as an attractive solution to improve road traffic management, thereby contributing to the European goal of safer, cleaner, and more efficient and sustainable traffic solutions. V2V-V2I communication technologies can improve traffic management through real-time exchange of data among vehicles and with road infrastructure. It is also of great importance to investigate the adequate combination of V2V and V2I technologies to ensure the continuous and costefficient operation of traffic management solutions based on wireless vehicular cooperative solutions. However, to adequately design and optimize these communication protocols and analyze the potential of wireless vehicular cooperative systems to improve road traffic management, adequate testbeds and field operational tests need to be conducted. Despite the potential of Field Operational Tests to get the first insights into the benefits and problems faced in the development of wireless vehicular cooperative systems, there is yet the need to evaluate in the long term and large dimension the true potential benefits of wireless vehicular cooperative systems to improve traffic efficiency. To this aim, iTETRIS is devoted to the development of advanced tools coupling traffic and wireless communication simulators

Virtual Access Points for Vehicular Networks

ABSTRACT This paper introduces the concept of Virtual Access Points (VAPs) for wireless Vehicular Ad-hoc Networks (VANETS). This new technique allows data dissemination among vehicles, thus extending the reach of roadside access points to uncovered road areas. Each vehicle that receives a message from an Access Point (AP) stores this message and rebroadcasts it into non covered areas. This extends the network coverage for non time critical messages. The VAP role is transparent to the connected nodes, and designed to avoid interference since each operates on a bounded region outside any AP. The experiments show the presented mechanism of store and forward at specific positions present a gain, in term of all the evaluated parameters