On Mobility Management in Multi-Sink Sensor Networks for Geocasting of Queries

In order to efficiently deal with location dependent messages in multi-sink wireless sensor networks (WSNs), it is key that the network informs sinks what geographical area is covered by which sink. The sinks are then able to efficiently route messages which are only valid in particular regions of the deployment. In our previous work (see the 5th and 6th cited documents), we proposed a combined coverage area reporting and geographical routing protocol for location dependent messages, for example, queries that are injected by sinks. In this paper, we study the case where we have static sinks and mobile sensor nodes in the network. To provide up-to-date coverage areas to sinks, we focus on handling node mobility in the network. We discuss what is a better method for updating the routing structure (i.e., routing trees and coverage areas) to handle mobility efficiently: periodic global updates initiated from sinks or local updates triggered by mobile sensors. Simulation results show that local updating perform very well in terms of query delivery ratio. Local updating has a better scalability to increasing network size. It is also more energy efficient than ourpreviously proposed approach, where global updating in networks have medium mobility rate and speed

Energy efficient geographic routing for wireless sensor networks.

A wireless sensor network consists of a large number of low-power nodes equipped with wireless radio. For two nodes not in mutual transmission range, message exchanges need to be relayed through a series of intermediate nodes, which is a process known as multi-hop routing. The design of efficient routing protocols for dynamic network topologies is a crucial for scalable sensor networks. Geographic routing is a recently developed technique that uses locally available position information of nodes to make packet forwarding decisions. This dissertation develops a framework for energy efficient geographic routing. This framework includes a path pruning strategy by exploiting the channel listening capability, an anchor-based routing protocol using anchors to act as relay nodes between source and destination, a geographic multicast algorithm clustering destinations that can share the same next hop, and a lifetime-aware routing algorithm to prolong the lifetime of wireless sensor networks by considering four important factors: PRR (Packet Reception Rate), forwarding history, progress and remaining energy. This dissertation discusses the system design, theoretic analysis, simulation and testbed implementation involved in the aforementioned framework. It is shown that the proposed design significantly improves the routing efficiency in sensor networks over existing geographic routing protocols. The routing methods developed in this dissertation are also applicable to other location-based wireless networks

Routing and Security in Mobile Ad Hoc Networks

A Mobile Ad hoc Network (MANET) consists of a set of nodes which can form a network among themselves. MANETs have applications in areas such as military, disaster rescue operations, monitoring animal habitats, etc. where establishing fixed communication infrastructure is not feasible. Routing protocols designed for MANETs can be broadly classified as position-based (geographic), topology-based and hybrid. Geographic routing uses location information of nodes to route messages. Topology-based routing uses network state information for route discovery and maintenance. Hybrid routing protocols use features in both position-based and topology-based approaches. Position-based routing protocols route packets towards the destination using greedy forwarding (i.e., an intermediate node forwards packets to a neighbor that is closer to the destination than itself). If a node has no neighbor that is closer to the destination than itself, greedy forwarding fails. In this case, we say there is void. Different position-based routing protocols use different methods for dealing with voids. Topology-based routing protocols can be classified into on-demand (reactive) routing protocols and proactive routing protocols. Generally, on-demand routing protocols establish routes when needed by flooding route requests throughout the entire network, which is not a scalable approach. Reactive routing protocols try to maintain routes between every pair of nodes by periodically exchanging messages with each other which is not a scalable approach also. This thesis addresses some of these issues and makes the following contribution. First, we present a position-based routing protocol called Greedy Routing Protocol with Backtracking (GRB) which uses a simple backtracking technique to route around voids, unlike existing position-based routing protocols which construct planarized graph of the local network to route around voids. We compare the performance of our protocol with the well known Greedy Perimeter Stateless Routing (GPSR) protocol and the Ad-Hoc On-demand Distance Vector (AODV) routing protocol as well as the Dynamic Source Routing (DSR) protocol. Performance evaluation shows that our protocol has less control overhead than those of DSR, AODV, and GPSR. Performance evaluation also shows that our protocol has a higher packet-delivery ratio, lower end-to-end delay, and less hop count, on average, compared to AODV, DSR and GPSR. We then present an on-demand routing protocol called ``Hybrid On-demand Greedy Routing Protocol with Backtracking for Mobile Ad-Hoc Networks which uses greedy approach for route discovery. This prevents flooding route requests, unlike the existing on-demand routing protocols. This approach also helps in finding routes that have lower hop counts than AODV and DSR. Our performance evaluation confirms that our protocol performs better than AODV and DSR, on average, with respect to hop count, packet-delivery ratio and control overhead. In MANETs, all nodes need to cooperate to establish routes. Establishing secure and valid routes in the presence of adversaries is a challenge in MANETs. Some of the well-known source routing protocols presented in the literature (e.g., Ariadne and endairA) which claim to establish secure routes are susceptible to hidden channel attacks. We address this issue and present a secure routing protocol called SAriadne, based on sanitizable signatures. We show that our protocol detects and prevents hidden channel attacks

FAR: Face-Aware Routing for Mobicast in Large-Scale Sensor Networks

This paper presents FAR, a Face-Aware Routing protocol for mobicast, a spatiotemporal variant of multicast tailored for sensor networks with environmental mobility. FAR features face-routing and timed-forwarding for delivering a message to a mobile delivery zone. Both analytical and statistical results show that, FAR achieves reliable and just-in-time mes-sage delivery with only moderate communication and memory overhead. This paper also presents a novel distributed algorithm for spatial neighborhood discovery for FAR boot-strapping. The spatiotemporal performance and reliability of FAR are demonstrated via ns-2 simulations

3D Geographical routing in wireless sensor networks

In this paper, we present a novel 3D geographical routing algorithm (3DGR) that makes use of the position information to route packets from sources to destinations with high path quality and reliability. The locality and high scalability of this algorithm make it suitable for wireless sensor networks. It provides high adaptability to changes in topology and recovery of link failures which increases its reliability. We also incorporate the battery-aware energy efficient schemes to increase the overall lifetime of the network. To reduce latency, a method of keeping a small record of recent paths is used. We also show that location errors still result in good performance of our algorithm while the same assumptions might yield to bad performance or even complete failures in others. Simulation results show that the power consumption and delay using 3DGR are close to optimal obtainable based on full knowledge of the network

The Four Principles of Geographic Routing

Geographic routing consists in using the position information of nodes to assist in the routing process, and has been a widely studied subject in sensor networks. One of the outstanding challenges facing geographic routing has been its applicability. Authors either make some broad assumptions on an idealized version of wireless networks which are often unverifiable, or they use costly methods to planarize the communication graph. The overarching questions that drive us are the following. When, and how should we use geographic routing? Is there a criterion to tell whether a communication network is fit for geographic routing? When exactly does geographic routing make sense? In this paper we formulate the four principles that define geographic routing and explore their topological consequences. Given a localized communication network, we then define and compute its geographic eccentricity, which measures its fitness for geographic routing. Finally we propose a distributed algorithm that either enables geographic routing on the network or proves that its geographic eccentricity is too high.Comment: This manuscript on geographic routing incoporates team feedback and expanded experiment

Reliable Mobicast via Face-Aware Routing

This paper presents a novel protocol for a spatiotemporal variant of multicast called mobicast, designed to support message delivery in sensor and mobile ad hoc networks. The spatiotemporal character of mobicast relates to the obligation to deliver a message to all the nodes that will be present at time t in some geographic zone Z, where both the location and shape of the delivery zone are a function of time over some interval (tstart, tend). The protocol, called Face-Aware Routing (FAR), exploits ideas adapted from existing applications of face routing to achieve reliable mobicast delivery. The key features of the protocol are a routing strategy, which uses information confined solely to a node’s immediate spatial neighborhood, and a forwarding schedule, which employs only local topological information. Statistical results showing that, in uniformly distributed random disk graphs, the spatial neighborhood size is usually less than 20 suggest that FAR is likely to exhibit a low average memory cost. An estimation formula for the average size of the spatial neighborhood in random network is another analytical result reported in this paper. This paper also includes a novel and low cost distributed algorithm for spatial neighborhood discovery

Improving Routing Efficiency through Intermediate Target Based Geographic Routing

The greedy strategy of geographical routing may cause the local minimum problem when there is a hole in the routing area. It depends on other strategies such as perimeter routing to find a detour path, which can be long and result in inefficiency of the routing protocol. In this paper, we propose a new approach called Intermediate Target based Geographic Routing (ITGR) to solve the long detour path problem. The basic idea is to use previous experience to determine the destination areas that are shaded by the holes. The novelty of the approach is that a single forwarding path can be used to determine a shaded area that may cover many destination nodes. We design an efficient method for the source to find out whether a destination node belongs to a shaded area. The source then selects an intermediate node as the tentative target and greedily forwards packets to it, which in turn forwards the packet to the final destination by greedy routing. ITGR can combine multiple shaded areas to improve the efficiency of representation and routing. We perform simulations and demonstrate that ITGR significantly reduces the routing path length, compared with existing geographic routing protocols

Would Current Ad Hoc Routing Protocols be Adequate for the Internet of Vehicles? A Comparative Study

In recent years we have seen a great proliferation of smart vehicles, ranging from cars to little drones (both terrestrial and aerial), all endowed with sensors and communication capabilities. It is hence easy to foresee a future with even more smart and connected vehicles moving around, occupying space and creating an Internet of Vehicles (IoV). In this IoV, a multitude of nodes (both static and mobile) will generate a continuous multihop flow of local information to support local smart environment applications. Therefore, one interesting environment for the IoV would be in the form of 3-D mobile ad-hoc networks (MANETs). Unfortunately, MANET routing protocols have generally been designed and analyzed keeping in mind a 2-D scenario; there is no guarantee on how they would support a 3-D topology of the IoV. To this end, we have considered routing protocols deemed as the state-of-the-art for classic MANETs and tested them over 3-D topologies to evaluate their assets and technical challenges