A number of geolocation-based Delay Tolerant Networking (DTN) routing protocols have been shown to perform well in selected simulation and mobility scenarios. However, the suitability of these mechanisms for vehicular networks utilizing widely-available inexpensive Global Positioning System (GPS) hardware has not been evaluated. We propose a novel geolocation-based routing primitive (Centroid Routing) that is resilient to the measurement errors commonly present in low-cost GPS devices. Using this notion of Centroids, we construct two novel routing protocols and evaluate their performance with respect to positional errors as well as traditional DTN routing metrics. We show that they outperform existing approaches by a significant margin.
Our routing primitive design takes inspiration from a number of location-based routing protocols developed for mobile ad-hoc networks, including Vector, APRAM, DREAM, SIFT, and GRID @cite_1 @cite_15 @cite_4 @cite_13 @cite_10 @cite_2 . Vector maximizes message spreading by preferentially transferring messages to neighbors traveling in a direction orthogonal to the node's own direction of travel. It calculates the trajectory vectors from repeated GPS samples. APRAM @cite_14 utilizes GPS coordinates to discover the geographically shortest path to the destination, while DREAM uses the cached node locations to make local forwarding decisions that forward packets in the direction of the destination. Similarly, AeroRP @cite_21 1sp @cite_6 1sp @cite_17 uses both the coordinates and velocity of neighbors to locally determine the best next hop. LAR @cite_20 uses location information to bound the area of the route discovery phase, thus reducing overhead. Beaconless geographic routing @cite_11 exploits the broadcast nature of wireless channels to overhead the location of neighboring nodes, and use this information to discover the best route. Other protocols such as IGF @cite_19 , BOSS @cite_9 , and BLR @cite_5 have been proposed that vary in the algorithm used to select the forwarding node.
@cite_14 @cite_4 @cite_11 @cite_10 @cite_9 @cite_21 @cite_1 @cite_6 @cite_19 @cite_2 @cite_5 @cite_15 @cite_13 @cite_20 @cite_17
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Geographic routing has emerged as one of the most efficient and scalable routing solutions for wireless sensor networks. In traditional geographic routing protocols, each node exchanges periodic one-hop beacons to determine the position of its neighbors. Recent studies proved that these beacons can create severe problems in real deployments due to the highly dynamic and error-prone nature of wireless links. To avoid these problems, new variants of geographic routing protocols that do not require beacons are being proposed. In this article we review some of the latest proposals in the field of beacon-less geographic routing and introduce the main design challenges and alternatives. In addition, we perform an empirical study to assess the performance of beacon-based and beacon-less routing protocols using a real WSN deployment. We present an overview of ad hoc routing protocols that make forwarding decisions based on the geographical position of a packet's destination. Other than the destination's position, each node need know only its own position and the position of its one-hop neighbors in order to forward packets. Since it is not necessary to maintain explicit routes, position-based routing does scale well even if the network is highly dynamic. This is a major advantage in a mobile ad hoc network where the topology may change frequently. The main prerequisite for position-based routing is that a sender can obtain the current position of the destination. Therefore, previously proposed location services are discussed in addition to position-based packet forwarding strategies. We provide a qualitative comparison of the approaches in both areas and investigate opportunities for future research. Geographic routing (GR) algorithms, require nodes to periodically transmit HELLO messages to allow neighbors know their positions (beaconing mechanism). To reduce the control overhead due to theses messages, beacon-less routing algorithms have recently been proposed. However, existing beacon-less algorithms have not considered realistic physical layers. Therefore, those algorithms can not work properly in realistic scenarios. In this paper we present a new beacon-less routing protocol called BOSS. Its design is based on the conclusions of our open-field experiments using Tmote-sky sensors. BOSS is adapted to error-prone networks and uses a new delay function to reduce collisions and duplicate messages produced during the phase of selecting the next forwarder. Through extensive simulations we compare BOSS with BLR and CBF and show that our scheme is able to achieve almost perfect packet delivery ratio (like BLR) while having a low bandwidth consumption (even lower than CBF). With the increasing importance of networked systems for telemetry, there is a need for efficient routing algorithms in aeronautical environments. Unlike traditional mobile networks, the highly dynamic nature of airborne networks results in extremely short-lived paths, especially for multi-hop scenarios thereby necessitating domain-specific protocols. In this paper, we present the detailed design and evaluation of AeroRP, a cross-layered routing protocol designed specifically for airborne telemetry applications. AeroRP exploits the broadcast nature of the wireless medium along with the physical node location and trajectory to improve the data delivery in Mach-speed mobile scenarios. We present a multi-modal protocol that addresses various operational scenarios of test and telemetry networks. Preliminary simulation results show that AeroRP significantly outperforms traditional MANET routing protocols while limiting the overhead. Highly-dynamic wireless environments present unique challenges to end-to-end communication networks, caused by the time-varying connectivity of high-velocity nodes combined with the unreliability of the wireless communication channel. Such conditions are found in a variety of networks, including those used for tactical communications and aeronautical telemetry. Addressing these challenges requires the design of new protocols and mechanisms specific to this environment. We present a new domain-specific architecture and protocol suite, including cross-layer optimizations between the physical, MAC, network, and transport layers. This provides selectable reliability for multiple applications within highly mobile tactical airborne networks. Our contributions for this environment include the transmission control protocol (TCP)-friendly transport protocol, AeroTP; the IP-compatible network layer, AeroNP; and the geolocation aware routing protocol AeroRP. Through simulations we show significant performance improvement over the traditional TCP IP MANET protocol stack. Wireless Sensor Networks (WSNs) are being designed to solve a gamut of interesting real-world problems. Limitations on available energy and bandwidth, message loss, high rates of node failure, and communication restrictions pose challenging requirements for these systems. Beyond these inherent limitations, both the possibility of node mobility and energy conserving protocols that power down nodes introduce additional complexity to routing protocols that depend on up to date routing or neighborhood tables. Such state-based protocols suffer excessive delay or message loss, as system dynamics require expensive upkeep of these tables. Utilizing characteristics of high node density and location awareness, we introduce IGF, a location-aware routing protocol that is robust and works without knowledge of the existence of neighboring nodes (state-free). We compare our work against established routing protocols to demonstrate the efficacy of our solution when nodes are mobile or periodically sleep to conserve energy. We show that IGF far outperforms these protocols, in some cases delivering close to 100 of the packets transmitted while alternate solutions fail to even find a path between a source and destination. Specifically, we show that our protocol demonstrates a vast improvement over prior work using metrics of delivery ratio, control overhead, and end-to-end delay. Routing in ad hoc networks is a complicated task because of many reasons. The nodes are low-memory, low-powered, and they cannot maintain routing tables large enough for well-known routing protocols. Because of that, greedy forwarding at intermediate nodes is desirable in ad hoc networks. Also, for traffic engineering, multi-path capabilities are important. So, it is desirable to define routes at the source like in source based routing (SBR) while performing greedy forwarding at intermediate nodes. We investigate trajectory-based routing (TBR) which was proposed as a middle-ground between SBR and greedy forwarding techniques. In TBR, source encodes trajectory to be traversed and embeds it into each packet. Upon the arrival of each packet, intermediate nodes decode the trajectory and employ greedy forwarding techniques such that the packet follows its trajectory as much as possible. In this paper, we address various issues regarding implementation of TBR. We also provide techniques to efficiently forward packets along a trajectory defined as a parametric curve. We use the well-known Bezier parametric curve for encoding trajectories into packets at source. Based on this trajectory encoding, we develop and evaluate various greedy forwarding algorithms Routing of packets in mobile ad hoc networks with a large number of nodes or with high mobility is a very difficult task and current routing protocols do not really scale well with these scenarios. The beacon-less routing algorithm (BLR) presented in this paper is a routing protocol that makes use of location information to reduce routing overhead. However, unlike other position-based routing protocols, BLR does not require nodes to periodically broadcast Hello-messages (called beaconing), and thus avoids drawbacks such as extensive use of scarce battery-power, interferences with regular data transmission, and performance degradation. BLR selects a forwarding node in a distributed manner among all its neighboring nodes with having information neither about their positions nor even about their existence. Data packets are broadcasted and the protocol takes care that just one of the receiving nodes forwards the packet. Optimized forwarding is achieved by applying a concept of dynamic forwarding delay. Consequently, the node that computes the shortest forwarding delay relays the packet first. This forwarding is detected by the other nodes and suppresses them to relay the same packet any further. Analytical results and simulation experiments indicate that BLR provides efficient and robust routing in highly dynamic mobile ad hoc networks. A mobile ad hoc network (MANET) is one consisting of a set of mobile hosts capable of communicating with each other without the assistance of base stations. One prospective direction to assist routing in such an environment is to use location information provided by positioning devices such as global positioning systems (GPS). In this paper, we propose a new routing protocol called GRID, which tries to exploit location information in route discovery, packet relay, and route maintenance. Existing protocols, as compared to ours, are either not location-aware or partially location-aware in that location knowledge is not fully exploited in all these three aspects. One attractive feature of our protocol is its strong route maintenance capability --- the intermediate hosts of a route can perform a "handoff" operation similar to that in cellular systems when it roams away to keep a route alive. This makes routes in the MANET more stable and insensitive to host mobility. Simulation results show that our GRID routing protocol can reduce the probability of route breakage, reduce the number of route discovery packets used, and lengthen routes' lifetime. Geographic forwarding is an emerging paradigm for communications between nodes in sensor networks. No exchange of location information is required, and nodes only have to know their own coordinates and those of the destination. Due to the device's limited processing and storage capabilities, a simplified protocol architecture should be designed so as to make communications in these networks efficient and simple at the same time. Moreover, sensor nodes are battery supplied and, thus, protocol design should be aimed at reducing energy consumption in order to increase network lifetime. In this perspective, one sensor feature recently regarded as of key importance, is the ability to tune the transmission power. This allows the communication range to be varied according to node density and connectivity constraints. In this paper we propose an integrated cross-layer protocol, called MACRO, which integrates MAC and routing layer functionalities in order to support geographic forwarding in wireless sensor networks. In MACRO, a competition is triggered to select the best next relay node while forwarding information to the destination. The competition is based on the evaluation of a weighted progress factor representing the progress towards the destination per unit of transmission power. An analytical paradigm facilitating the most appropriate choice of the next relay is proposed. The proposed solution is assessed through both analysis and ns-2 simulations. Performance results show the advantages of the proposed solution when compared to other geographic forwarding protocols which do not exploit cross-layer features.