1,721,068 research outputs found
Random walk with long jumps for wireless ad hoc networks
No full textThis paper considers a random walk-based search algorithm in which the random walk occasionally makes longer jumps. The algorithm is tailored to work over wireless networks with uniform node distribution. In a classical random walk each jump has the same mean length. On the contrary, in the proposed algorithm a node may decide to double the expected jump length by increasing the nominal transmission power and picking a neighbor beyond the nominal range. The aim of these long jumps is reducing the spatial correlation among short term subsequent node selections, thus improving the search performance, namely the hitting time. Two versions of the algorithm are studied, with and without lookahead. A protocol for implementing each version is also proposed. When there is no lookahead the proposed protocol allows for a finer transmission power transmission regulation. The paper studies, for three network topologies, the impact of the long jump probability on the hitting time and on the average total power required before the target is found. (C) 2008 Elsevier B.V. All rights reserved
The polarized gossip protocol for path discovery in MANETs
No full textIn this paper we present a novel probabilistic protocol for path discovery in Mobile Ad Hoc Networks (MANETs). The protocol implements what we call a polarized gossiping algorithm. While in the classical gossip algorithm each node forwards a message with the same probability, our proposal is characterized by a variable gossiping probability, which is high enough only for sustaining the spreading process towards the destination. The gossiping probability of a node is determined by the difference between its proximity to the destination and the proximity to the destination of the node from which the message was received. Differently from other proposals no external location service support, e.g., via GPS, is required. Rather, the proximity is estimated from the "inside" of the network using periodic beacons for determining the time elapsed since a node met the destination and the dwell time of a node with the destination. These information are then exploited by nodes to modulate their gossiping probability. The paper reports a mathematical model for the analysis of the algorithm along with an extensive simulation study of its implementation, which shows the suitability of the proposed solution. (C) 2006 Elsevier B.V. All rights reserved
On Message Delivery through Approximate Information in Highly Dynamic Mobile Ad Hoc Networks
No full text
A directional gossip protocol for path discovery in MANETs
Full text linkIn this paper we present a gossip based protocol for path discovery in Mobile Ad Hoc Networks (MANETs). While in the classical gossip algorithm each node forwards a packet with the same probability, our proposal is characterized by a variable gossiping probability, which is high enough only for sustaining the spreading process towards the destination. No external location service, e.g. via GPS, is required to determine the gossip probability at each node; rather, the estimation is done from the "inside" of the network by using periodic beacons. The paper reports a simulation study and a mathematical model for better understanding the property of the directional gossip process. © 2006 IEEE
A caching scheme for routing in mobile ad hoc networks and its application to ZRP
No full textA large class of routing protocols for MANETs, namely, reactive protocols, employ some form of caching to reduce the number of route discoveries. The simplest form of caching is based on associating a timeout with each cache entry. Such timer-based cache schemes can increase the protocol efficiency. However, if the timeout is not well-tuned, a severe performance degradation arises as entries are removed either too early or too late from the cache. In this paper, we address the problem of designing a proactive cache scheme that does not rely on any timer-based mechanism. This scheme guarantees that valid cached routes are never removed while stale routes are removed aggressively. This proactive cache scheme has been embedded in the Zone Routing Protocol (ZRP) framework and evaluated by an extensive simulation study
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