Approaching Optimal Centralized Scheduling with CSMA-based Random Access over Fading Channels

Carrier Sense Multiple Access (CSMA) based distributed algorithms can attain the largest capacity region as the centralized Max-Weight policy does. Despite their capability of achieving throughput-optimality, these algorithms can either incur large delay and have large complexity or only operate over non-fading channels. In this letter, by assuming arbitrary back-off time we first propose a fully distributed randomized algorithm whose performance can be pushed to the performance of the centralized Max-Weight policy not only in terms of throughput but also in terms of delay for completely-connected interference networks with fading channels. Then, inspired by the proposed algorithm we introduce an implementable distributed algorithm for practical networks with a reservation scheme. We show that the proposed practical algorithm can still achieve the performance of the centralized Max-Weight policy.Comment: accepted to IEEE Communications Letter

Load-aware Channel Selection for 802.11 WLANs with Limited Measurement

It has been known that load unaware channel selection in 802.11 networks results in high level interference, and can significantly reduce the network throughput. In current implementation, the only way to determine the traffic load on a channel is to measure that channel for a certain duration of time. Therefore, in order to find the best channel with the minimum load all channels have to be measured, which is costly and can cause unacceptable communication interruptions between the AP and the stations. In this paper, we propose a learning based approach which aims to find the channel with the minimum load by measuring only limited number of channels. Our method uses Gaussian Process Regressing to accurately track the traffic load on each channel based on the previous measured load. We confirm the performance of our algorithm by using experimental data, and show that the time consumed for the load measurement can be reduced up to 46% compared to the case where all channels are monitored.Comment: accepted to IC

On road network utility based on risk-aware link choice

Sémelin, J., Purifier et détruire. Usages politiques des massacres et génocides, coll. « La Couleur des idées », Paris, Le Seuil, 2005. Jacques Sémelin poursuit sa vaste exploration de la violence en menant une réflexion approfondie sur ses formes les plus extrêmes, les plus négatrices : la violence dans ce qu’elle a de plus macabre, de plus terrifiant, de plus absurde ou de proprement sidérant. L’auteur de ce grand livre oriente sa recherche vers ce qui paraît toujours plus inintelligible, l..

A Dynamic Location Management Scheme based on individual metrics and coordinates

Location management in cellular networks have been in focus for the research community for a number of years. The current static method of determining location or paging areas has been shown to be suboptimal and costly for operators. Therefore, much research has been focussed on dynamic schemes, which show great promise in cost optimisation. However, the research has still been focussed on aggregation of user behaviour and location area determination based on the aggregate. In thi

A Task-Based Approach to Data and Context Management in Virtual Personal Server Space

This paper presents our vision for an activity based pervasive computing system based on a virtual personal server space. Our target demographic is a group of elder computer users. Using collaborative inter faces technologies; we focus on reminiscence activities for their use in promoting social and intellectual fitness. Current computer applications while designed for single use are not suitable for multi-user, multi-device and multi-modal interaction. Our proposed architecture (middleware) consists of three planes of service (data, context and activity). The context plane mediates access to various services (depending on the current user activity) while optimizing data access around simple activity models