Adaptive and occupancy-based channel selection for unreliable cognitive radio networks

In this paper, we propose an adaptive and occupancy-based channel selection for unreliable cognitive radio networks

Toward Reliable Contention-aware Data Dissemination in Multi-hop Cognitive Radio Ad Hoc Networks

This paper introduces a new channel selection strategy for reliable contentionaware data dissemination in multi-hop cognitive radio network. The key challenge here is to select channels providing a good tradeoff between connectivity and contention. In other words, channels with good opportunities for communication due to (1) low primary radio nodes (PRs) activities, and (2) limited contention of cognitive ratio nodes (CRs) acceding that channel, have to be selected. Thus, by dynamically exploring residual resources on channels and by monitoring the number of CRs on a particular channel, SURF allows building a connected network with limited contention where reliable communication can take place. Through simulations, we study the performance of SURF when compared with three other related approaches. Simulation results confirm that our approach is effective in selecting the best channels for efficient and reliable multi-hop data dissemination

SURF: A Distributed Channel Selection Strategy for Data Dissemination in Multi-Hop Cognitive Radio Networks

In this paper, we propose an intelligent and distributed channel selection strategy for efficient data dissemination in multi-hop cognitive radio network. Our strategy, SURF, classifies the available channels and uses them efficiently to increase data dissemination reliability in multi-hop cognitive radio networks. The classification is done on the basis of primary radio unoccupancy and of the number of cognitive radio neighbors using the channels. Through extensive NS-2 simulations, we study the performance of SURF compared to three related approaches. Simulation results confirm that our approach is effective in selecting the best channels for efficient communication (in terms of less primary radio interference) and for highest dissemination reachability in multi-hop cognitive radio networks

Activity Pattern Impact of Primary Radio Nodes on Channel Selection Strategies

International audienceThe performance of cognitive radio network is highly dependent upon the primary radio nodes activity pattern. In this paper, we study and analyze the impact of different PR nodes activity pattern with the help of three performance metrics. In this perspective, we use our channel selection strategy SURF and three other channel selection strategies i.e., Random (RD), Highest Degree (HD), and Selective Broadcasting (SB). We analyze the performance of these channel selection strategies through extensive NS-2 simulations. Moreover, we also analyze how these strategies respond to different PR nodes activity. Simulation results confirm that SURF outperforms RD, HD, and SB in terms of delivery ratio and causes less harmful interference to PR nodes, in all primary radio nodes activity pattern

Reasoning Services for Security and Energy Management in Wireless Sensor Networks

Abstract-In this paper we propose a management scheme based on automated reasoning for wireless sensor networks. Our scheme ensures reliable zone surveillance with reduced energy consumption, a crucial constraint in sensors networks and in tomorrow's green communication platforms. We divide the zone to monitor into a set of areas each containing a management node that implements reasoning services. The management node centralizes alerts issued by sensors in the area, correlates them, and raises an alarm to the administrator only if a real event occurs. Moreover, each sensor runs a set of reasoning functions that limit its communication with the management node of its area. Through simulations we show that our scheme reduces considerably the number of messages sent from sensor to management nodes as well as alarms raised by the management nodes to the administrator without missing events in the monitored zone. Hence our management ensures reliable surveillance and extends the sensor network lifetime in the same time

Toward Reliable Contention-aware Data Dissemination in Multi-hop Cognitive Radio Ad Hoc Networks

This report was first published as: INRIA RR-0375, 2009, France. http://hal.inria.fr/inria-00441892/en/. Now, the report number is changed i.e. RR-7288 and can be accessible at: http://hal.archives-ouvertes.fr/inria-00482910/en/.This paper introduces a new channel selection strategy for reliable contention-aware data dissemination in multi-hop cognitive radio network. The key challenge here is to select channels providing a good tradeoff between connectivity and contention. In other words, channels with good opportunities for communication due to (1) low primary radio nodes (PRs) activities, and (2) limited contention of cognitive ratio nodes (CRs) acceding that channel, have to be selected. Thus, by dynamically exploring residual resources on channels and by monitoring the number of CRs on a particular channel, SURF allows building a connected network with limited contention where reliable communication can take place. Through simulations, we study the performance of SURF when compared with three other related approaches. Simulation results confirm that our approach is effective in selecting the best channels for efficient and reliable multi-hop data dissemination

Interaction Between Hidden Node Collisions and Congestions in Multihop Wireless Ad-hoc Networks

In this work, we study the performance of the IEEE 802.11 MAC protocol and its impact on the transport layer performance in multihop wireless ad-hoc networks. We focus on the hidden node problem that effects heavily the end-to-end delay and the packet loss probability. Through a mathematical analysis, we compute the packet loss probability as a function of the load. We develop a simplified model of a multihop wireless network and we use it to analyze the interaction between collision and congestion. We find that reducing the size of the MAC output queue can increase the applications throughput. This is done by setting the adequate buffer size that makes congestions and collisions operate in the same region. This will also allow closed or open-loop control protocols such as TCP to react correctly to losses caused by collisions as well as losses caused by buffer overflow. Simulation results with TCP traffic corroborate our theoretical analysis

Routage dans les réseaux radios cognitifs

National audienceNous présentons une approche de routage spécifique aux réseaux radios cognitifs tenant compte de l'activité et de l'emplacement des noeuds prioritaires appelés primaires. Notre routage s'effectue en deux phases : dans la première, et à l'aide d'une métrique probabiliste, nous attribuons un poids à chaque lien ; cela permet de trouver le meilleur chemin vers la destination. Dans la seconde phase nous vérifions que les capacités sur chaque lien choisi vérifient la demande D de l'application en terme de débit en ajoutant des fréquences entre les noeuds où cette contrainte n'est pas vérifiée. Nous montrons avec des analyses numériques que le nombre de connexions acceptées dépend des caractéristiques imposées par les noeuds primaires et aussi de la fiabilité demandée par l'application qui utilise le réseau cognitif