1,505 research outputs found
Energy-aware Ad Hoc on-demand distance vector routing protocol and optimizing the blocking problem induced in wireless Ad Hoc networks
The purpose of this thesis was to investigate some of the issues related to routing and medium access control protocol in ad hoc networks. In routing protocol, the goal is to tackle the power consumption problem and to present a case for using new cost energy-aware metric for Ad Hoc On-Demand Distance Vector (AODV). The idea of the new cost metric is to be able to avoid routes with a low energy capacity. By using this approach, high efficiency in energy consumption can be achieved in Ad-Hoc networks.
The second goal of this thesis was to investigate the blocking problem induced by Request-to-Send/Clear-to-Send (RTS/CTS) mechanism in detail and provide a solution to overcome that problem. To do so, a new parameter is proposed by which the Medium Access control (MAC) protocol will decide when to switch between RTS/CTS mechanism (the 4-way-handshaking) and the Basic Access method (the 2-way-handshaking) in order to reduce the effect of the blocking problem in Ad Hoc networks
Multi-objective function-based node-disjoint multipath routing for mobile ad hoc networks
Funding Information: This work was supported Korea Environmental Industry & Technology Institute (KEITI) grant funded by the Korea government (Ministry of Environment). Project No. RE202101551, the development of IoT-based technology for collecting and managing Big data on environmental hazards and health effects.Peer reviewedPublisher PD
On-demand Bandwidth and Stability Based Unicast Routing in Mobile Adhoc Networks
Characteristics of mobile ad hoc networks (MANETs) such as lack of central coordination, dynamic topology and limited resources pose a challenging problem in quality of service (QoS) routing. Providing an efficient, robust and low overhead QoS unicast route from source to destination is a critical issue. Bandwidth and route stability are the major important QoS parameters for applications where long duration connections are required with stringent bandwidth requirements for multimedia applications. This paper proposes an On-demand Bandwidth and Stability based Unicast Routing scheme (OBSUR) in MANET by adding additional QoS features to existing Dynamic Source Routing (DSR) protocol. The objective of the OBSUR is to provide QoS satisfied, reliable and robust route for communicating nodes. The scheme works in following steps. (1) Each node in the network periodically (small regular intervals) estimates bandwidth availability, node and link stability, buffer availability, and stability factor between nodes. (2) Construction of neighbor stability and QoS database at every node which is used in route establishment process. (3) The unicast path is constructed by using route request and route reply packets with the help of route information cache, and (4) route maintenance in case of node mobility and route failures. Simulation results show that there is an improvement in terms of traffic admission ratio, control overhead, packet delivery ratio, end to end delay and throughput as compared to Route Stability Based QoS Routing (RSQR) in MANETs.
Enhancing Performance by Salvaging Route Reply Messages in On-Demand Routing Protocols for MANETs
Researchers prefer on-demand routing protocols in mobile ad hoc networks where resources such as energy and bandwidth are constrained. In these protocols, a source discovers a route to a destination typically by flooding the entire or a part of the network with a route request (RREQ) message. The destination responds by sending a route reply (RREP) message to the source. The RREP travels hop by hop on the discovered route in the reverse direction or on another route to the source. Sometimes the RREP can not be sent to the intended next hop by an intermediate node due to node mobility or network congestion. Existing on-demand routing protocols handle the undeliverable RREP as a normal data packet - discard the packet and initiate a route error message. This is highly undesirable because a RREP message has a lot at stake – it is obtained at the cost of a large number of RREQ transmissions, which is an expensive and timeconsuming process. In this paper, we propose the idea of salvaging route reply (SRR) to improve the performance of on-demand routing protocols. We present two schemes to salvage an undeliverable RREP. Scheme one actively sends a one-hop salvage request message to find an alternative path to the source, while scheme two passively maintains a backup path to the source. Furthermore, we present the design of two SRR schemes in AODV and prove that routes are loop-free after a salvaging. We conduct extensive simulations to evaluate the performance of SRR, and the simulation results confirm the effectiveness of the SRR approach
Snapshots of the EYES project
The EYES project (IST-2001-34734) is a three years European research project on self-organizing and collaborative energy-efficient sensor networks. It addresses the convergence of distributed information processing, wireless communications, and mobile computing. The goal of the project is to develop the architecture and the technology which enables the creation of a new generation of sensors that can effectively network together so as to provide a flexible platform for the support of a large variety of mobile sensor network applications. This paper provides a broad overview of the EYES project and highlights some approaches and results of the architecture
On Link Estimation in Dense RPL Deployments
The Internet of Things vision foresees billions of
devices to connect the physical world to the digital world. Sensing
applications such as structural health monitoring, surveillance or
smart buildings employ multi-hop wireless networks with high
density to attain sufficient area coverage. Such applications need
networking stacks and routing protocols that can scale with
network size and density while remaining energy-efficient and
lightweight. To this end, the IETF RoLL working group has
designed the IPv6 Routing Protocol for Low-Power and Lossy
Networks (RPL). This paper discusses the problems of link quality
estimation and neighbor management policies when it comes
to handling high densities. We implement and evaluate different
neighbor management policies and link probing techniques in
Contiki’s RPL implementation. We report on our experience
with a 100-node testbed with average 40-degree density. We show
the sensitivity of high density routing with respect to cache sizes
and routing metric initialization. Finally, we devise guidelines for
design and implementation of density-scalable routing protocols
Cache timeout strategies for on-demand routing in MANETs
Varying the route caching scheme can significantly
change network performance for on-demand routing protocols
in mobile ad hoc networks (MANETs). Initial
route caching schemes retain paths or links until they are
shown to be broken. However, stale routing information
can degrade network performance with latency and extra
routing overhead. Therefore, more recent caching schemes
delete links at some fixed time after they enter the cache.
This paper proposes using either the expected path duration
or the link residual time as the link cache timeout.
These mobility metrics are theoretically calculated for an
appropriate random mobility model. Simulation results in
NS2 show that both of the proposed link caching schemes
can improve network performance in the dynamic source
routing protocol (DSR) by reducing dropped data packets,
latency and routing overhead, with the link residual time
scheme out-performing the path duration scheme.IEEE, South Australian Sectio
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