296 research outputs found
Naming and Address Resolution in Heterogeneous Mobile Ad hoc Networks
No full textThis doctoral thesis deals with naming and address resolution in heterogeneous networks to be used in disaster scenarios. Such events could damage the communication infrastructure in parts or completely. To reestablish communication, Mobile Ad hoc Networks (MANETs) could be used where central entities have to be eliminated broadly. The main focus of the thesis lies on two things: an addressing scheme that helps to find nodes, even if they frequently change the subnet and the local addressing, by introducing an identifying name layer; and a MANET-adapted substitution of the Domain Name System (DNS) in order to resolve node identities to changing local addresses. We present our solution to provide decentralized name resolution based on different underlying routing protocols embedded into an adaptive routing framework. Furthermore, we show how this system works in cascaded networks and how to extend the basic approach to realize location-aware service discovery.Auch im Buchhandel erhältlich:
Naming and Address Resolution in Heterogeneous Mobile Ad hoc Networks / Sebastian Schellenberg
Ilmenau : Univ.-Verl. Ilmenau, 2016. - xvi, 177 Seiten
ISBN 978-3-86360-129-4
Preis (Druckausgabe): 17,60
TP-UrbanX - A New Transport Protocol for Cognitive Multi-Radio Mesh Networks
No full textUrban-X is a new architecture for Multi-Radio Cognitive Mesh Networks based on principles from Dynamic Spectrum Access Networks. In the Urban-X, spectrum sensing and mobility are challenging a transport control protocol (TCP) whose performance is sensitive to varying delay and available bandwidth. Also high packet loss due to primary users lets standard TCP to operate inefficiently. In this study, we propose a new transport protocol TP-UrbanX for the Urban-X which exploits reinforcement based learning techniques to learn an optimal sending rate and adapt this rate given the dynamics of the environment such as spectrum sensing and channel mobility
(YIP-07) Economic Models for End-to-End Decision Making in an AD HOC Network Environment
No full textTrust based channel preference in cognitive radio networks under collaborative selfish attacks
No full textSecondary spectrum data falsification (SSDF) is a common attack in cognitive radio networks, where dishonest nodes share spurious local sensing data. This behavior misleads the collective inference on spectrum occupancy. The situation is more aggravated when a collaborative SSDF attack is launched by a coalition of selfish nodes. Defense against such collaborative attacks is difficult with popularly used voting based inference models. This paper proposes a method based on Bayesian inference that indicates how much the collective decision on a channel\u27s occupancy can be trusted. Using an anomaly monitoring technique, we check if the reports sent by a node match with the expected occupancy and classify the outcomes into three categories: i) if there is a match, ii) if there is a mismatch, and iii) if it cannot be decided. Based on the measured observations over time, we estimate the parameters of the hypothesis of match and mismatch events using a multinomial Bayesian based inference. We quantitatively define the trust as the difference between the posterior beliefs associated with matches and that of mismatches. The posterior beliefs are updated based on a weighted average of the prior information on the belief itself and the recently observed data. We conduct simulation experiments that show that the proposed trust model is able to distinguish the attacked channels from the non-attacked ones. Also, a node is able to rank the channels based on how trustworthy the inference on a channel is. We are also able to show that attacked channels have significantly lower trust values than channels that are not
Effects of internet path selection on video-QoE
No full textThis paper presents large scale Internet measurements to understand and improve the effects of Internet path selection on perceived video quality. We systematically study a large number of Internet paths between popular video destinations and clients to create an empirical understanding of location, persistence and recurrence of failures. We map these failures to perceptual quality by reconstructing video clips obtained from the trace to quantify both the perceptual degradations from these failures as well as the fraction of such failures that can be recovered. We then investigate ways to recover from QoE degradation by choosing one-hop detour paths that preserve application specific policies. We seek simple, scalable path selection strategies without the need for background path monitoring or apriori path knowledge of any kind. To do this, we deployed five measurement overlays: one each in the US, Europe, Asia-Pacific, and two spread across the globe. We used these to stream IP-traces of a variety of clips between source-destination pairs while probing alternate paths for an entire week. Our results indicate that a source can recover from upto 90% of the degradations by attempting to restore QoE with any five randomly chosen nodes in an overlay. We argue that our results are robust across datasets. Finally, we design and implement a prototype packet forwarding module called source initiated frame restoration (SIFR). We deployed SIFR on PlanetLab nodes, and compared the performance of SIFR with the default Internet routing. We show that SIFR outperforms IP-path selection by providing higher on-screen perceptual quality. Copyright 2010 ACM
Spectrum map aided multi-channel multi-hop routing in distributed cognitive radio networks
No full textIn this paper, we propose a spectrum map aided routing protocol for a distributed cognitive radio network. We assume the presence of dedicated sensors that capture the spatio-temporal spectrum usage statistics to create the radio environment map. We exploit the map to find not only the best hops along a route but also the best available channel in terms of the expected performance. Through the use of edge nodes, which lie in the intersection of more than one sensors\u27 domain, inter-domain routing is facilitated. The selection of each hop, the channel to be used per hop, and the transmitting power to be used considers i) protection of primary receivers, and ii) maximization of desired performance metric. In this context, we propose a novel power control mechanism that computes just enough power to maintain the desired signal-to-noise ratio for secondary communication but at the same time protects the primary receivers in the vicinity. We analyze and compute the probability of network connectivity by finding the minimum spanning tree of the graph formed by the over-lapping domains. Through simulations, we show how the proposed routing scheme works in terms of route capacity, connectivity of the network, reachability among the nodes, and number of primary receivers protected
A Bargaining Game for Channel Access in Dynamic Spectrum Access Networks
No full textIn this paper, we model the problem of dynamic spectrum access by a set of cognitive radio enabled nodes as an infinite horizon bargaining game. Each node (or, player) negotiates with its interfering nodes to obtain an agreeable sharing rule of the available channels.We investigate the subgame perfect equilibrium strategies of the bargaining game, abiding by which, each node can maximize its throughput against all its interfering nodes (opponents). We further study the issue of fairness in this model, in terms of the relative number of channels allocated to the nodes. Moreover, each node bargains with its interfering neighbors independently and in a distributed manner, making the system scalable. ©2010 IEEE
Mitigating Self-Interference Among IEEE 802.22 Networks: A Game Theoretic Perspective
No full textIn this paper, we use game theory to mitigate self-interference among cognitive radio based IEEE 802.22 networks such that these networks can efficiently co-exist. When a network experiences interference, it can adopt either one of two choicess-witch to a new band hoping to find a non-interfering one, or stay with its current band hoping that the interfering network(s) will move away to a new band. We model the spectrum band switching process as an infinite horizon repeated game where the aim of each network (player) is to find a channel void of interference from it\u27s neighboring networks incurring minimal cost. We investigate both pure and mixed strategy solution space of the game and show that pure strategy solution of the game is infeasible. Thus a mixed strategy is proposed which achieves subgame-perfect Nash Equilibrium. Simulation results reveal that using the proposed strategies, each network can find a clear channel quickly and at the same time incur a low cost
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