Spectrum mobility management in cognitive two‐tier networks

Recently, new type of small Base Station known as “femtocell” has emerged. Femtocells are deployed by customers with minimal or no radio frequency planning in arbitrary locations. Thus, operators must use new approaches rather than the classic network planning and optimization. Self‐organization techniques will allow femtocells to integrate themselves into the network, learn about their environment, and adjust their parameters (power, frequency) accordingly. In this paper, a new spectrum mobility management algorithm is proposed. It allows intelligent use of the spectrum by secondary user (femtocell guest user) accessing spectrum holes unoccupied by primary users (subscriber user) and handing over to new channels or femtocells when primary user appears. Our solution aims to have more adaptive and aware communication system, which can make better use of available natural resources.     

Energy Efficiency Optimization for Wireless Body Area Networks Under 802.15.6 Standard

Wireless Personal Communications - With the attractive applications in e-Health, a booming interest is granted to wireless body area network (WBAN). Through WBAN, healthcare professionals can...     

Conception d’une solution de sélection de passerelles Internet dans les réseaux ad hoc

In the past few years, Internet has raised increasing interest in various areas including research, education, and business. The number of people accessing the Internet at work or at home has increased considerably, just like the number of services offered (email, e-commerce, search engines, e-learning, e-government, etc.). Ad hoc networks were generally viewed as stand-alone networks, where communications are only supported between nodes in the network such as in military and rescue operations. The lack of connectivity to the wired infrastructure enables simple management and deployment, but limits the applicability of ad hoc networks to today’s scenarios, which require connectivity outside the ad hoc network and particularly to the Internet. However, to reach this goal, a number of problems need to be resolved because of the dynamic nature of such environment. In this article, we describe a new solution for dynamic gateway selection based on quality of service (QoS) criteria. The underlying architecture is based on a pro-active routing protocol.     

Scheduling evacuation operations

In this paper, we consider a large-scale evacuation problem after a major disaster. The evacuation is assumed to occur by means of a fleet of buses, thus leading to scheduling the evacuation operations by buses [(bus evacuation problem (BEP)]. We propose time-indexed formulations as well as heuristic algorithms such as greedy algorithms and a matheuristic. This matheuristic uses the former formulation to improve the best solution obtained by the greedy heuristics. In computational experiments, we analyze and evaluate the efficiency of the proposed solution algorithms.     

A survey on interference management techniques in femtocell self-organizing networks

The femtocell concept is an emerging technology for deploying the next generation of the wireless networks, aiming at indoor coverage enhancement, increasing capacity, and offloading the overlay macrocell traffic. Nevertheless, one of the most critical issues in femtocells is the potential interference between nearby femtocells and from femtocells to macrocells or to mobile handsets, thus mitigating the overall system capacity.In this paper, we have discussed mechanisms which can be deployed to lessen the interference and increase the user capacity. Therefore, we provide a survey on the different interference and resource management techniques in Self-Organizing Network according to specifics classification criteria. These techniques derive from the following approaches: power control, proper cell planning, frequency reuse, OFDMA, self-configuration and self-optimization, conventional TDD, etc. These techniques can be applied separately and can be used as hybrid. A qualitative comparison among the different approaches and techniques is provided at the end of this paper.