Showing papers on "Geographic routing published in 2002"

Energy aware routing for low energy ad hoc sensor networks

Abstract: The recent interest in sensor networks has led to a number of routing schemes that use the limited resources available at sensor nodes more efficiently. These schemes typically try to find the minimum energy path to optimize energy usage at a node. In this paper we take the view that always using lowest energy paths may not be optimal from the point of view of network lifetime and long-term connectivity. To optimize these measures, we propose a new scheme called energy aware routing that uses sub-optimal paths occasionally to provide substantial gains. Simulation results are also presented that show increase in network lifetimes of up to 40% over comparable schemes like directed diffusion routing. Nodes also burn energy in a more equitable way across the network ensuring a more graceful degradation of service with time.

The impact of data aggregation in wireless sensor networks

Abstract: Sensor networks are distributed event-based systems that differ from traditional communication networks in several ways: sensor networks have severe energy constraints, redundant low-rate data, and many-to-one flows. Data-centric mechanisms that perform in-network aggregation of data are needed in this setting for energy-efficient information flow. In this paper we model data-centric routing and compare its performance with traditional end-to-end routing schemes. We examine the impact of source-destination placement and communication network density on the energy costs and delay associated with data aggregation. We show that data-centric routing offers significant performance gains across a wide range of operational scenarios. We also examine the complexity of optimal data aggregation, showing that although it is an NP-hard problem in general, there exist useful polynomial-time special cases.

Geographical and Energy Aware Routing: a recursive data dissemination protocol for wireless sensor networks

Abstract: Future sensor networks will be composed of a large number of densely deployed sensors/actuators. A key feature of such networks is that their nodes are untethered and unattended. Consequently, energy efficiency is an important design consideration for these networks. Motivated by the fact that sensor network queries may often be geographical, we design and evaluate an energy efficient routing algorithm that propagates a query to the appropriate geographical region, without flooding. The proposed Geographic and Energy Aware Routing (GEAR) algorithm uses energy aware neighbor selection to route a packet towards the target region and Recursive Geographic Forwarding or Restricted Flooding algorithm to disseminate the packet inside the destina-

Rumor Routing Algorithm For Sensor Networks

Abstract: in micro-sensor and radio technology will enable small but smart sensors to be deployed for a wide range of environmental monitoring applications. In order to constrain communication overhead, dense sensor networks call for new and highly efficient methods for distributing queries to nodes that have observed interesting events in the network. A highly efficient data-centric routing mechanism will offer significant power cost reductions (17), and improve network longevity. Moreover, because of the large amount of system and data redundancy possible, data becomes disassociated from specific node and resides in regions of the network (10)(7)(8). This paper describes and evaluates through simulation a scheme we call Rumor Routing, which allows for queries to be delivered to events in the network. Rumor Routing is tunable, and allows for tradeoffs between setup overhead and delivery reliability. It's intended for contexts in which geographic routing criteria are not applicable because a coordinate system is not available or the phenomenon of interest is not geographically correlated.

Rumor routing algorthim for sensor networks

Abstract: Advances in micro-sensor and radio technology will enable small but smart sensors to be deployed for a wide range of environmental monitoring applications. In order to constrain communication overhead, dense sensor networks call for new and highly efficient methods for distributing queries to nodes that have observed interesting events in the network. A highly efficient data-centric routing mechanism will offer significant power cost reductions [17], and improve network longevity. Moreover, because of the large amount of system and data redundancy possible, data becomes disassociated from specific node and resides in regions of the network [10][7][8]. This paper describes and evaluates through simulation a scheme we call Rumor Routing, which allows for queries to be delivered to events in the network. Rumor Routing is tunable, and allows for tradeoffs between setup overhead and delivery reliability. It's intended for contexts in which geographic routing criteria are not applicable because a coordinate system is not available or the phenomenon of interest is not geographically correlated.

Position-based routing in ad hoc networks

Abstract: The availability of small, inexpensive low-power GPS receivers and techniques for finding relative coordinates based on signal strengths, and the need for the design of power-efficient and scalable networks provided justification for applying position-based routing methods in ad hoc networks. A number of such algorithms were developed previously. This tutorial will concentrate on schemes that are loop-free, localized, and follow a single-path strategy, which are desirable characteristics for scalable routing protocols. Routing protocols have two modes: greedy mode (when the forwarding node is able to advance the message toward the destination) and recovery mode (applied until return to greedy mode is possible). We discuss them separately. Methods also differ in metrics used (hop count, power, cost, congestion, etc.), and in past traffic memorization at nodes (memoryless or memorizing past traffic). Salient properties to be emphasized in this review are guaranteed delivery, scalability, and robustness.

ARA-the ant-colony based routing algorithm for MANETs

Abstract: A mobile ad-hoc network (MANET) is a collection of mobile nodes which communicate over radio. These kind of networks are very flexible, thus they do not require any existing infrastructure or central administration. Therefore, mobile ad-hoc networks are suitable for temporary communication links. The biggest challenge in this kind of networks is to find a path between the communication end points, what is aggravated through the node mobility. In this paper we present a new on-demand routing algorithm for mobile, multi-hop ad-hoc networks. The protocol is based on swarm intelligence and especially on the ant colony based meta heuristic. These approaches try to map the solution capability of swarms to mathematical and engineering problems. The introduced routing protocol is highly adaptive, efficient and scalable. The main goal in the design of the protocol was to reduce the overhead for routing. We refer to the protocol as the ant-colony-based routing algorithm (ARA).

Modelling Data-Centric Routing in Wireless Sensor Networks

Abstract: Sensor networks differ from traditional net- works in several ways: sensor networks have severe en- ergy constraints, redundant low-rate data, and many-to-one flows. The end-to-end routing schemes that have been pro- posed in the literature for mobile ad-hoc networks are not appropriate under these settings. Data-centric technologies are needed that perform in-network aggregation of data to yield energy-efficient dissemination. In this paper we model data-centric routing and compare its performance with tra- ditional end-to-end routing schemes. We examine the im- pact of source-destination placement and communication network density on the energy costs, delay, and robustness of data aggregation. We show that data-centric routing offers significant performance gains across a wide range of opera- tional scenarios.

Geographic routing of emergency service call center emergency calls

Abstract: The present invention is related to the delivery of requests for emergency service initially handled by an emergency service call center to a public safety answering point. The invention additionally allows for enhancement information to be provided to a public safety answering point operator visually in connection with calls routed to that public safety answering point. This information may include caller identification, and additional information, such as information regarding the location of the caller and the nature of the emergency. Furthermore, the routing of requests for emergency service to an appropriate public safety answering point can be accomplished for requests received over a wide geographic area. In particular, requests can be appropriately routed even though they may originate from locations encompassed by different E9-1-1 tandems. The present invention is particularly well suited for use in connection with automatic collision notification and personal alarm monitoring call centers serving areas encompassed by more than one E9-1-1 tandem.

Constrained random walks on random graphs: routing algorithms for large scale wireless sensor networks

Abstract: We consider a routing problem in the context of large scale networks with uncontrolled dynamics. A case of uncontrolled dynamics that has been studied extensively is that of mobile nodes, as this is typically the case in cellular and mobile ad-hoc networks. In this paper however we study routing in the presence of a different type of dynamics: nodes do not move, but instead switch between active and inactive states at random times. Our interest in this case is motivated by the behavior of sensor nodes powered by renewable sources, such as solar cells or ambient vibrations. In this paper we formalize the corresponding routing problem as a problem of constructing suitably constrained random walks on random dynamic graphs. We argue that these random walks should be designed so that their resulting invariant distribution achieves a certain load balancing property, and we give simple distributed algorithms to compute the local parameters for the random walks that achieve the sought behavior. A truly novel feature of our formulation is that the algorithms we obtain are able to route messages along all possible routes between a source and a destination node, without performing explicit route discovery/repair computations, and without maintaining explicit state information about available routes at the nodes. To the best of our knowledge, these are the first algorithms that achieve true multipath routing (in a statistical sense), at the complexity of simple stateless operations.

The Application of Remote Sensor Technology To Assist the Recovery of Rare and Endangered Species

Abstract: We describe a wireless sensor network designed for the long-term study of rare and endangered species of plants We wish to monitor plants and their environment via high-resolution cameras and temperature, humidity, rainfall, wind, and solar radiation sensors Our units must be A¢Â€ÂœinvisibleA¢Â€Â camouflaged, very low energy, and must allow distributed local computation Data rates are 1 to 100 bytes/second per node, but networks can be large - an early prototype had 60 nodes Failures are expensive and we must exploit redundancy whenever possible Nodes are stationary but for energy reasons may decline to participate in transmissions We have designed two wireless routing protocols that satisfy these constraints Multipath On-demand Routing MOR computes multiple optimal routes to avoid depleting the energy at any given node Geometric Routing scales to large networks, relying on Geographic Routing when possible and on selected global information otherwise We have simulated and are implementing both protocols

Fixed-alternate routing and wavelength conversion in wavelength-routed optical networks

Abstract: Consider an optical network which employs wavelength-routing crossconnects that enable the establishment of wavelength-division-multiplexed (WDM) connections between node pairs. In such a network, when there is no wavelength conversion, a connection is constrained to be on the same wavelength channel along its route. Alternate routing can improve the blocking performance of such a network by providing multiple possible paths between node pairs. Wavelength conversion can also improve the blocking performance of such a network by allowing a connection to use different wavelengths along its route. This work proposes an approximate analytical model that incorporates alternate routing and sparse wavelength conversion. We perform simulation studies of the relationships between alternate routing and wavelength conversion on three representative network topologies. We demonstrate that alternate routing generally provides significant benefits, and that it is important to design alternate routes between node pairs in an optimized fashion to exploit the connectivity of the network topology. The empirical results also indicate that fixed-alternate routing with a small number of alternate routes asymptotically approaches adaptive routing in blocking performance.

MRPC: maximizing network lifetime for reliable routing in wireless environments

Abstract: We propose MRPC, a new power-aware routing algorithm for energy-efficient routing that increases the operational lifetime of multi-hop wireless networks. In contrast to conventional power-aware algorithms, MRPC identifies the capacity of a node not just by its residual battery energy, but also by the expected energy spent in reliably forwarding a packet over a specific link. Such a formulation better captures scenarios where link transmission costs also depend on physical distances between nodes and the link error rates. Using a max-min formulation, MRPC selects the path that has the largest packet capacity at the 'critical' node (the one with the smallest residual packet transmission capacity). We also present CMRPC, a conditional variant of MRPC that switches from minimum energy routing to MRPC only when the packet forwarding capacity of nodes falls below a threshold. Simulation based studies have been used to quantify the performance gains of our algorithms.

Method and system for providing network based target advertising

Abstract: A telecommunication system implements a method for providing a targeted on-line advertisement to a user accessing a content provider node of the system. The system further comprises an ad selection node and an user identification node. A user signal indicative of an information request is routed through the system to determine a geographic location of the user and/or a demographic profile of the geographic location. An advertiser corresponding to the geographic location and/or demographic profile is thereafter communicated to the user.

Survivable lightpath routing: a new approach to the design of WDM-based networks

Abstract: Network restoration is often done at the electronic layer by rerouting traffic along a redundant path. With wavelength-division multiplexing (WDM) as the underlying physical layer, it is possible that both the primary and backup paths traverse the same physical links and would fail simultaneously in the event of a link failure. It is, therefore, critical that lightpaths are routed in such a way that a single link failure would not disconnect the network. We call such a routing survivable and develop algorithms for survivable routing of a logical topology. First, we show that the survivable routing problem is NP-complete. We then prove necessary and sufficient conditions for a routing to be survivable and use these conditions to formulate the problem as an integer linear program (ILP). Due to the excessive run-times of the ILP, we develop simple and effective relaxations for the ILP that significantly reduces the time required for finding survivable routings. We use our new formulation to route various logical topologies over a number of different physical topologies and show that this new approach offers a much greater degree of protection than alternative routing schemes such as shortest path routing and a greedy routing algorithm. Finally, we consider the special case of ring logical topologies for which we are able to find a significantly simplified formulation. We establish conditions on the physical topology for routing logical rings in a survivable manner.

Predictive location-based QoS routing in mobile ad hoc networks

Abstract: In mobile ad hoc networks, the locations and resource-richness of mobile nodes vary dynamically. The information used for routing by traditional routing protocols becomes obsolete due to node mobility. To overcome this problem, a predictive location-based QoS routing scheme is needed. We present a location-delay prediction scheme, based on a location-resource update protocol, which assists a QoS routing protocol. Simulation results show that our approach can predict the location at a given instant in the future with a high degree of accuracy.

Performance comparison of two location based routing protocols for ad hoc networks

Abstract: Many location based routing protocols have been developed for ad hoc networks. This paper presents the results of a detailed performance evaluation on two of these protocols: location-aided routing (LAR) and distance routing effect algorithm for mobility (DREAM). We compare the performance of these two protocols with the dynamic source routing (DSR) protocol and a minimum standard (i.e., a protocol that floods all data packets). We used NS-2 to simulate 50 nodes moving according to the random waypoint model. Our main goal for the performance investigation was to stress the evaluated protocols with high data loads during both low and high speeds. Our performance investigation produced the following conclusions. First, the added protocol complexity of DREAM does not appear to provide benefits over a flooding protocol. Second, promiscuous mode operation improves the performance of DSR significantly. Third, adding location information to DSR (i.e., similar to LAR) increases both the network load and the data packet delivery ratio; our results conclude that the increase in performance is worth the increase in cost. Lastly, our implementation of DREAM provides a simple location service that could be used with other ad hoc network routing protocols.

Wireless routing protocol for ad-hoc networks

Abstract: Method for selecting a route within a wireless ad-hoc routing protocol using a QoS metric. The method begins by dynamically defining a routing zone that encompasses at least two of the network nodes. A communications link is established between the source node and a destination node. If the destination node is within the routing zone of the source node, the route is determined by a proactive routing protocol. If, however, the destination node is outside the routing zone, the route is determined using a reactive routing protocol. A QoS metric for each route is calculated by combining the individual QoS metrics for each hop within the particular route. Finally, the route with the best QoS metric is selected to use as the communications link between the source node and the destination node.

Location information services in mobile ad hoc networks

Abstract: In previous years, many location based routing protocols have been developed for ad hoc networks. Some of these protocols assume a location service exists which provides location information on all the mobile nodes in the network. We evaluate three location service alternatives. One is a reactive protocol; the other two are proactive protocols. Of the proactive protocols, one sends location tables to neighbors and the other sends location information to all nodes. In our evaluation, one proactive protocol proved to have the best performance overall. Thus, we also evaluate the main input parameter associated with this protocol for optimal performance.

Mobile agents based routing protocol for mobile ad hoc networks

Abstract: A novel routing scheme for mobile ad hoc networks (MANETs), which combines the on-demand routing capability of Ad Hoc On-Demand Distance Vector (AODV) routing protocol with a distributed topology discovery mechanism using ant-like mobile agents is proposed in this paper. The proposed hybrid protocol reduces route discovery latency and the end-to-end delay by providing high connectivity without requiring much of the scarce network capacity. On the one side the proactive routing protocols in MANETs like Destination Sequenced Distance Vector (DSDV) require to know, the topology of the entire network. Hence they are not suitable for highly dynamic networks such as MANETs, since the topology update information needs to be propagated frequently throughout the network. These frequent broadcasts limit the available network capacity for actual data communication. On the other hand, on-demand, reactive routing schemes like AODV and Dynamic Source Routing (DSR), require the actual transmission of the data to be delayed until the route is discovered. Due to this long delay a pure reactive routing protocol may not be applicable for real-time data and multimedia communication. Through extensive simulations in this paper it is proved that the proposed Ant-AODV hybrid routing technique, is able to achieve reduced end-to-end delay compared to conventional ant-based and AODV routing protocols.

Position optimized wireless communication

Abstract: A wireless communication base station consistent with certain embodiments of the present invention collects user transmissions and creates and maintains a database storing data that relates communication parameters to a geographic location. A base station receiver receives data packets containing data describing a geographic location of a mobile communication node. The base station predicts a future geographic location of the mobile communication node, and transmits communication parameters to the mobile communication node associated with the predicted future geographic location. The mobile communication node consistent with certain embodiments of the invention has a GPS positioning device that determines a geographic location of the communication node. A transceiver transmits data representing the geographic location and receives data representing communication parameters determined as a function of the data representing the geographic location. The mobile communication node adjusts its communication parameters in response thereto for the predicted geographic location.

Efficient flooding with Passive Clustering (PC) in ad hoc networks

Abstract: An ad hoc network is a fast deployable self-configuring wireless network characterized by node mobility, dynamic topology structure, unreliable media and limited power supply. Nodes in an ad hoc network must cooperate and carry out a distributed routing protocol in order to make multi-hop communications possible. On Demand Routing is one of the most popular routing styles in ad hoc networks. In On Demand Routing, "flooding" is used to find a feasible route from source to destination. The function of flooding is to deliver a packet from one source to every other node in the system. Conventional flooding can be very costly in On Demand networks in terms of network throughput efficiency as well as node energy consumption. The main reason is that the same packet is rebroadcast unnecessarily several times (redundant rebroadcast). Indeed, the penalty of redundant rebroadcast increases when the size of network grows and the density of network increases. In this paper we introduce a novel clustering scheme, call Passive Clustering that can reduce the redundant rebroadcast effect in flooding. We demonstrate the efficiency of the proposed scheme in the AODV (Ad hoc, On demand Distance Vector) routing scheme.

A comparison of routing strategies for vehicular ad-hoc networks

Abstract: On this paper we investigate the use of ad-hoc routing algorithms for the exchange of data between vehicles There are two main aspects that are of interest in this context: the specific characteristics of ad-hoc networks formed by vehicles and the applicability of existing ad-hoc routing schemes to networks that display these characteristics In order to address both aspects we generate realistic vehicular movement patterns of highway traffic scenarios using a well validated traffic simulation tool Based on these patterns we show that the characteristics of vehicular ad-hoc networks are quite different from the frequently used random waypoint model We then proceed to evaluate the performance of a reactive ad-hoc routing protocol (DSR) and of a position-based approach (greedy forwarding as done in GPSR) in combination with a simple reactive location service Our analysis suggests that for vehicular networks where communication spans more than 2 or 3 hops position-! based ad-hoc routing has significant advantages over reactive non-position-based approaches both in the number of successfully delivered packets and in routing overhead

A constrained shortest-path energy-aware routing algorithm for wireless sensor networks

Abstract: While traditional routing protocols try to minimize the end-to-end delay or maximize the throughput, most energy-aware routing protocols for wireless sensor networks try to extend the life time of the network by minimizing the energy consumption sacrificing other performance metrics. We introduce a new energy-aware routing protocol that tries to minimize the energy consumption and, at the same time, maintain good end-to-end delay and throughput performance. The new algorithm is based on a constrained shortest-path algorithm. We compare the new algorithm with some traditional routing and energy-aware routing algorithms. The results show that the new algorithm performance is acceptable under all performance metrics and presents a performance balance between the traditional routing algorithms and the energy-aware routing algorithms. The constraint value can be chosen to achieve different performance objectives for different sensor network missions.

Robust routing in wireless ad hoc networks

Abstract: A wireless ad hoc network is a collection of mobile nodes with no fixed infrastructure. The absence of a central authorization facility in dynamic and distributed environments requires collaboration among nodes. When a source searches for a route to a destination, an intermediate node can reply with its cached entry. To strengthen correctness of such a routing discovery process, we propose a method in which the intermediate node requests its next hop to send a confirmation message to the source. After receiving both a route reply and confirmation message, the source determines the validity of a path according to its policy. As a result, this strategy discourages malicious nodes from intercepting packets. Simulation results show a remarkable improvement in throughput (30% higher delivery ratio and 10% less data transmission overhead) with a moderate increase of control messages.

Link stability and route lifetime in ad-hoc wireless networks

Abstract: Many routing algorithms, proposed for ad-hoc wireless networks, are based on source routing scheme. When a route is broken in source routing, route recovery and maintenance procedures are executed. However these procedures consume many resources. To minimize route breaking, it important to find a route that endures longer time. Shortest path route has short lifetime especially in highly dense ad-hoc wireless networks, and it due to the edge effect discovered in this paper Some routing protocols such as SSA and ABR are considering the link stability and try finding more stable route. In this paper, we will focus on the link stability and the lifetime of a route, and propose link stability comparison models for previously proposed routing algorithms. We will show properties of these models and compare them with local optimal algorithm that finds longest lifetime route at a given time. Finally, we will propose an enhanced link stability estimation model to find a route with longer lifetime.

A Reactive Location Service for Mobile Ad Hoc Networks

Abstract: We present and analyze a reactive location service RLS for mobile ad hoc networks. RLS provides a mobile node in a wireless ad-hoc network with the means to inquire the current geographical position of another node on-demand and can be used as a building block for location-based routing. We provide a comparison of RLS to an ideal omniscient location service as well as to the complex Grid Location Service (GLS). In addition, we compare the performance of greedy location-based routing in combination with RLS to the performance of a non-location-based ad hoc routing approach, namely Dynamic Source Routing (DSR). DSR was chosen for the comparison since RLS can be considered an adaptation of DSR\'s route discovery mechanisms to the location-based domain. We also introduce and study possible optimizations for RLS, in particular caching, random re-broadcast jitter, and re-broadcast suppression. The quantitative results of our NS-2 simulation study show a very good perform! ance of RLS combined with greedy routing, outperforming GLS and DSR for scenarios with high mobility and high node density.

MPR-based hybrid routing for mobile ad-hoc networks

Abstract: This paper describes the design and performance of a routing protocol for mobile ad-hoc networks. Our routing protocol is named "hybrid routing" in that it attempts to take advantage of both proactive and reactive approaches. The protocol is based on the concept of multipoint relaying (MPR) to minimize flooding traffic. For most applications over mobile ad-hoc networks, it is expected that a major portion of communication will be done in the two-hop region. Therefore, when a node needs a route to a destination in the two-hop region, it consults with the routing table as the proactive approach to find the route directly. Outside this region, on the other hand, it discovers a route on demand as the reactive approach through the use of MPR flooding. The proposed protocol has been validated using the ns network simulator with wireless and mobility extensions. The simulation results show that our MPR-HR protocol provides higher efficiency in terms of routing overhead compared to AODV one of the most efficient routing protocols released for mobile ad-hoc networks.

Method and system for routing packets through a network by employing geographical position data

Abstract: A geographic position dependent routing method and system for ad hoc networks, where are least one of the nodes of the ad hoc network can change its location. A position determination module is provided for determining the position of the current node. A communication mechanism is provided for communicating messages with other nodes in the ad hoc network. A geographic position dependent routing mechanism is coupled to the position determination module and communication mechanism for receiving messages, the position of the current node, and based thereon for one of transmitting the message and discarding the message.