Ad hoc wireless distribution service

About: Ad hoc wireless distribution service is a research topic. Over the lifetime, 17734 publications have been published within this topic receiving 488205 citations.

Simulation-based analysis of security exposures in mobile ad hoc networks

Abstract: The area of ad hoc networking has been receiving increasing attention among researchers in recent years and a variety of routing protocols targeted specifically at the ad hoc networking environment have been proposed. However, little information about the effects of security exposures in terms of network performance has previously been available. This paper provides a simulation study that identifies security issues that are specific to MANET and that illustrate the effects of those threats on network performance when the DSR routing protocol is used. We focused our attention on the evaluation of network performance in terms of global throughput and delay of a mobile ad hoc network where a defined percentage of nodes behaved selfishly. The simulation study brought up two important conclusions. First, it shows that security issues have to be taken into account at the early stages of a routing protocol design. Indeed, when no countermeasures are taken, the simulation results showed that network operation and maintenance can be easily jeopardized and network performance will severely degrade. Second, a cooperative security scheme seems to be a reasonable solution to the selfishness problem: a selfish behavior can be detected through the collaboration between a number of nodes assuming that a majority of nodes do not misbehave.

Quality of service routing in ad-hoc networks using OLSR

Abstract: In an ad-hoc network, all communication is done over wireless media, without the help of wired base stations. While many routing protocols have been developed to find and maintain routes based on a best-effort service model, quality-of-service (QoS) routing in an ad-hoc network is difficult because the network topology may change constantly and the available state information for routing is inherently imprecise. In this paper, we discuss how to support QoS routing in OLSR (optimized link state routing protocol, one of the routing protocols under study by the IETF MANET Working Group). We develop heuristics that allow OLSR to find the maximum bandwidth path, show through simulation that these heuristics do improve OLSR in the static network case, and finally, we prove that for our ad-hoc network model, two of the heuristics are indeed optimal (i.e., guarantee that the highest-bandwidth path between any two nodes is found).

Enhancing ad hoc routing with dynamic virtual infrastructures

Abstract: Several routing algorithms for mobile ad hoc networks (MANETs) have been proposed previously. With the exception of a few, these protocols (i) involve all nodes in the route management process, (ii) rely on the use of broadcast relays for route computation, and (iii) are primarily reactive in nature. Related work has shown that the capacity utilization in ad hoc networks decreases significantly when broadcast relays or "broadcast storms" are performed frequently. This effect is compounded when all nodes in the network take part in the route computation. We propose and study an approach based on overlaying a virtual infrastructure adaptation of the core, proposed by Sivakumar, Sinha and Bharghavan (see IEEE Journal on Selected Areas in Communications, vol.17, no.8, p.1454-65, 1999) on an ad hoc network and operating routing protocols over the infrastructure. The core enables routing protocols to use only a subset of nodes in the network for route management and avoid the use of broadcast relays. Using the ns-2 simulator we evaluate the performance of two ad hoc routing protocols, dynamic source routing (DSR) and ad hoc on demand distance vector (AODV), when they are operated over the core and compare their performance against those of their basic versions.

Ad hoc networking with directional antennas: a complete system solution

Abstract: In this paper, we present UDAAN ("utilizing directional antennas for ad hoc networking"), which is an interacting suite of modular network- and MAC-layer mechanisms for adaptive control of steered or switched antenna systems in an ad hoc network. UDAAN consists of several new mechanisms - a directional power-controlled MAC, neighbor discovery with beamforming, link characterization with directional antennas, proactive routing and forwarding all working cohesively to provide the first complete systems solution. We describe the development of a real-life ad hoc network testbed using UDAAN with switched directional antennas, and we discuss the lessons learned during field trials. High fidelity simulation results, using the same networking code as in the prototype, are also presented. For the range of parameters studied, our results show that UDAAN can produce up to a factor-of-10 improvement in throughput over omni-directional communications.