Energy-aware Dual-path Geographic Routing to Bypass Routing Holes in Wireless Sensor Networks

This is the author accepted manuscript. The final version is available from IEEE via the DOI in this record.Geographic routing has been considered as an attractive approach for resource-constrained wireless sensor networks (WSNs) since it exploits local location information instead of global topology information to route data. However, this routing approach often suffers from the routing hole (i.e., an area free of nodes in the direction closer to destination) in various environments such as buildings and obstacles during data delivery, resulting in route failure. Currently, existing geographic routing protocols tend to walk along only one side of the routing holes to recover the route, thus achieving suboptimal network performance such as longer delivery delay and lower delivery ratio. Furthermore, these protocols cannot guarantee that all packets are delivered in an energy-efficient manner once encountering routing holes. In this paper, we focus on addressing these issues and propose an energy-aware dual-path geographic routing (EDGR) protocol for better route recovery from routing holes. EDGR adaptively utilizes the location information, residual energy, and the characteristics of energy consumption to make routing decisions, and dynamically exploits two node-disjoint anchor lists, passing through two sides of the routing holes, to shift routing path for load balance. Moreover, we extend EDGR into three-dimensional (3D) sensor networks to provide energy-aware routing for routing hole detour. Simulation results demonstrate that EDGR exhibits higher energy efficiency, and has moderate performance improvements on network lifetime, packet delivery ratio, and delivery delay, compared to other geographic routing protocols in WSNs over a variety of communication scenarios passing through routing holes. The proposed EDGR is much applicable to resource-constrained WSNs with routing holes.This work has been partially supported by the National Natural Science Foundation of China (No. 61402343, No. 61672318, No. U1504614, No. 61631013, and No. 61303241), the National Key Research and Development Program (No. 2016YFB1000102), the Natural Science Foundation of Suzhou/Jiangsu Province (No. BK20160385), the EU FP7 QUICK Project (No. PIRSESGA- 2013-612652), and the projects of Tsinghua National Laboratory for Information Science and Technology (TNList)

Position-based routing and MAC protocols for wireless ad-hoc networks

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This thesis presents the Forecasting Routing Technique (FORTEL), a routing protocol for Mobile Ad-Hoc Networks (MANETs) based on the nodes’ Location Information. FORTEL stores the nodes’ location information in the Location Table (LT) in order to construct routes between the source and the destination nodes. FORTEL follows the source routing strategy, which has rarely been applied in position-based routing. According to the source routing strategy, the end-to-end route is attached to the packet, therefore, the processing cost, in regards to the intermediate nodes that simply relay the packet according to route, is minimized. FORTEL’s key mechanisms include: first, the location update scheme, employed to keep the LT entries up-to-date with the network topology. Besides the mobility variation and the constant rate location update schemes applied, a window location update scheme is presented to increase the LT’s information accuracy. Second, the switching mechanism, between “Hello” message and location update employed, to reduce the protocol’s routing overhead. Third and most important is the route computation mechanism, which is integrated with a topology forecasting technique to construct up-to-date routes between the communication peers, aiming to achieve high delivery rate and increase the protocol robustness against the nodes’ movement. FORTEL demonstrates higher performance as compared to other MANET’s routing protocols, and it delivers up to 20% more packets than AODV and up to 60 % more than DSR and OLSR, while maintaining low levels of routing overhead and network delay at the same time. The effectiveness of the window update scheme is also discussed, and it proves to increase FORTEL’s delivery rate by up to 30% as compared to the other update schemes. A common and frequently occurring phenomenon, in wireless networks, is the Hidden Terminal problem that significantly impacts the communication performance and the efficiency of the routing and MAC protocols. Beaconless routing approach in MANETs, which delivers data packets without prior knowledge of any sort `of information, suffers from packet duplication caused by the hidden nodes during the contention process. Moreover, the throughput of the IEEE MAC protocol decreases dramatically when the hidden terminal problem occurs. RTS/CTS mechanism fails to eliminate the problem and can further degrade the network’s performance by introducing additional overhead. To tackle these challenges, this thesis presents two techniques, the Sender Suppression Algorithm and the Location-Aided MAC, where both rely on the nodes’ position to eliminate packet duplication in the beaconless routing and improve the performance of the 802.11 MAC respectively. Both schemes are based on the concept of grouping the nodes into zones and assign different time delay to each one. According to the Sender Suppression Algorithm, the sender’s forwarding area is divided into three zones, therefore, the local timer, set to define the time that the receiver has to wait before responding to the sender’s transmission, is added to the assigned zone delay. Following the first response, the sender interferes and suppresses the receivers with active timer of. On the other hand, the Location-Aided MAC, essentially a hybrid MAC, combines the concepts of time division and carrier sensing. The radio range of the wireless receiver is partitioned into four zones with different zone delays assigned to each zone. Channel access within the zone is purely controlled by CSMA/CA protocol, while it is time-based amongst zones. The effectiveness of the proposed techniques is demonstrated through simulation tests. Location-Aided MAC considerably improves the network’s throughput compared to CSMA/CA and RTS/CTS. However, remarkable results come when the proposed technique and the RTS/CTS are combined, which achieves up to 20% more throughput as compared to the standalone RTS/CTS. Finally, the thesis presents a novel link lifetime estimation method for greedy forwarding to compute the link duration between two nodes. Based on a newly introduced Stability-Aware Greedy (SAG) scheme, the proposed method incorporates the destination node in the computation process and thus has a significant advantage over the conventional method, which only considers the information of the nodes composing the link

Graph embeddings for low-stretch greedy routing

The simplest greedy geometric routing forwards packets to make most progress in terms of geometric distance within reach. Its notable advantages are low complexity, and the use of local information only. However, two problems of greedy routing are that delivery is not always guaranteed, and that the greedy routes may take more hops than the corresponding shortest paths. Additionally, in dynamic multihop networks, routing elements can join or leave during network operation or exhibit intermittent failures. Even a single link or node removal may invalidate the greedy routing success guarantees. Greedy embedding is a graph embedding that makes the simple greedy packet forwarding successful for every source-destination pair. In this dissertation, we consider the problems of designing greedy graph embeddings that also yield low hop stretch of the greedy paths over the shortest paths and can accommodate network dynamics. In the first part of the dissertation, we consider embedding and routing for arbitrary unweighted network graphs, based on greedy routing and utilizing virtual node coordinates. We propose an algorithm for online greedy graph embedding in the hyperbolic plane that enables incremental embedding of network nodes as they join the network, without disturbing the global embedding. As an alternative to frequent reembedding of temporally dynamic network graphs in order to retain the greedy embedding property, we propose a simple but robust generalization of greedy geometric routing called Gravity--Pressure (GP) routing. Our routing method always succeeds in finding a route to the destination provided that a path exists, even if a significant fraction of links or nodes is removed subsequent to the embedding. GP routing does not require precomputation or maintenance of special spanning subgraphs and is particularly suitable for operation in tandem with our proposed algorithm for online graph embedding. In the second part of the dissertation we study how topological and geometric properties of embedded graphs influence the hop stretch. Based on the obtained insights, we synthesize embedding heuristics that yield minimal hop stretch greedy embeddings. Finally, we verify their effectiveness on models of synthetic graphs as well as instances of several classes of real-world network graphs

New techniques for geographic routing

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 141-148).As wireless sensor networks continue to grow in size, we are faced with the prospect of emerging wireless networks with hundreds or thousands of nodes. Geographic routing algorithms are a promising alternative to tradition ad hoc routing algorithms in this new domain for point-to-point routing, but deployments of such algorithms are currently uncommon because of some practical difficulties. This dissertation explores techniques that address two major issues in the deployment of geographic routing algorithms: (i) the costs associated with distributed planarization and (ii) the unavailability of location information. We present and evaluate two new algorithms for geographic routing: Greedy Distributed Spanning Tree Routing (GDSTR) and Greedy Embedding Spring Coordinates (GSpring). Unlike previous geographic routing algorithms which require the planarization of the network connectivity graph, GDSTR switches to routing on a spanning tree instead of a planar graph when packets end up at dead ends during greedy forwarding. To choose a direction on the tree that is most likely to make progress towards the destination, each GDSTR node maintains a summary of the area covered by the subtree below each of its tree neighbors using convex hulls.(cont.) This distributed data structure is called a hull tree. GDSTR not only requires an order of magnitude less bandwidth to maintain these hull trees than CLDP, the only distributed planarization algorithm that is known to work with practical radio networks, it often achieves better routing performance than previous planarization-based geographic routing algorithms. GSpring is a new virtual coordinate assignment algorithm that derives good coordinates for geographic routing when location information is not available. Starting from a set of initial coordinates for a set of elected perimeter nodes, GSpring uses a modified spring relaxation algorithm to incrementally adjust virtual coordinates to increase the convexity of voids in the virtual routing topology. This reduces the probability that packets will end up in dead ends during greedy forwarding, and improves the routing performance of existing geographic routing algorithms. The coordinates derived by GSpring yield comparable routing performance to that for actual physical coordinates and significantly better performance than that for NoGeo, the best existing algorithm for deriving virtual coordinates for geographic routing. Furthermore, GSpring is the first known algorithm that is able to derive coordinates that achieve better geographic routing performance than actual physical coordinates for networks with obstacles.by Ben Wing Lup Leong.Ph.D

Energy-efficient multi-criteria packet forwarding in multi-hop wireless networks

Reliable multi-hop packet forwarding is an important requirement for the implementation of realistic large-scale wireless ad-hoc networks. However, packet forwarding methods based on a single criterion, such as the traditional greedy geographic forwarding, are not sufficient in most realistic wireless settings because perfect-reception-within-rangecannot be assumed. Furthermore, methods where the selection of intermediate relaying nodes is performed at the transmitter-side do not adapt well to rapidly changing network environments. Although a few link-aware geographic forwarding schemes have been reported in the literature, the tradeoffs between multiple decision criteria and their impact on network metrics such as throughput, delay and energy consumption have not been studied. This dissertation presents a series of strategies aimed at addressing the challenges faced by the choice of relay nodes in error-prone dynamic wireless network environments. First, a single-criterion receiver-side relay election (RSRE) is introduced as a distributed alternative to the traditional transmitter-side relay selection. Contrary to the transmitter- side selection, at each hop, an optimal node is elected among receivers to relay packets toward the destination. Next, a multi-criteria RSRE, which factors multiple decision criteria in the election process at lower overhead cost, is proposed. A general cost metric in the form of a multi-parameter mapping function aggregates decision criteria into a single metric used to rank potential relay candidates. A two-criteria RSRE case study shows that a proper combination of greedy forwarding and link quality leads to higher energy efficiency and substantial improvement in the end-to-end delay. Last, mesh multi-path forwarding methods are examined. A generalized mesh construction algorithm in introduced to show impact of a mesh structure on network performance

New Techniques for Geographic Routing

PhD thesisAs wireless sensor networks continue to grow in size, we are facedwith the prospect of emerging wireless networks with hundreds orthousands of nodes. Geographic routing algorithms are a promisingalternative to tradition ad hoc routing algorithms in this new domainfor point-to-point routing, but deployments of such algorithms arecurrently uncommon because of some practical difficulties.This dissertation explores techniques that address two major issues inthe deployment of geographic routing algorithms: (i) the costsassociated with distributed planarization and (ii) the unavailabilityof location information. We present and evaluate two new algorithmsfor geographic routing: Greedy Distributed Spanning Tree Routing(GDSTR) and Greedy Embedding Spring Coordinates (GSpring).Unlike previous geographic routing algorithms which require theplanarization of the network connectivity graph, GDSTR switches torouting on a spanning tree instead of a planar graph when packets endup at dead ends during greedy forwarding. To choose a direction on thetree that is most likely to make progress towards the destination,each GDSTR node maintains a summary of the area covered by the subtreebelow each of its tree neighbors using convex hulls. This distributeddata structure is called a hull tree. GDSTR not only requires an orderof magnitude less bandwidth to maintain these hull trees than CLDP,the only distributed planarization algorithm that is known to workwith practical radio networks, it often achieves better routingperformance than previous planarization-based geographic routingalgorithms.GSpring is a new virtual coordinate assignment algorithm that derivesgood coordinates for geographic routing when location information isnot available. Starting from a set of initial coordinates for a set ofelected perimeter nodes, GSpring uses a modified spring relaxationalgorithm to incrementally adjust virtual coordinates to increase theconvexity of voids in the virtual routing topology. This reduces theprobability that packets will end up in dead ends during greedyforwarding, and improves the routing performance of existinggeographic routing algorithms.The coordinates derived by GSpring yield comparable routingperformance to that for actual physical coordinates and significantlybetter performance than that for NoGeo, the best existing algorithmfor deriving virtual coordinates for geographic routing. Furthermore,GSpring is the first known algorithm that is able to derivecoordinates that achieve better geographic routing performance thanactual physical coordinates for networks with obstacles

A survey on gas leakage source detection and boundary tracking with wireless sensor networks

Gas leakage source detection and boundary tracking of continuous objects have received a significant research attention in the academic as well as the industries due to the loss and damage caused by toxic gas leakage in large-scale petrochemical plants. With the advance and rapid adoption of wireless sensor networks (WSNs) in the last decades, source localization and boundary estimation have became the priority of research works. In addition, an accurate boundary estimation is a critical issue due to the fast movement, changing shape, and invisibility of the gas leakage compared with the other single object detections. We present various gas diffusion models used in the literature that offer the effective computational approaches to measure the gas concentrations in the large area. In this paper, we compare the continuous object localization and boundary detection schemes with respect to complexity, energy consumption, and estimation accuracy. Moreover, this paper presents the research directions for existing and future gas leakage source localization and boundary estimation schemes with WSNs

Position-based routing and MAC protocols for wireless ad-hoc networks

This thesis presents the Forecasting Routing Technique (FORTEL), a routing protocol for Mobile Ad-Hoc Networks (MANETs) based on the nodes' Location Information. FORTEL stores the nodes' location information in the Location Table (LT) in order to construct routes between the source and the destination nodes. FORTEL follows the source routing strategy, which has rarely been applied in position-based routing. According to the source routing strategy, the end-to-end route is attached to the packet, therefore, the processing cost, in regards to the intermediate nodes that simply relay the packet according to route, is minimized. FORTEL's key mechanisms include: first, the location update scheme, employed to keep the LT entries up-to-date with the network topology. Besides the mobility variation and the constant rate location update schemes applied, a window location update scheme is presented to increase the LT's information accuracy. Second, the switching mechanism, between "Hello" message and location update employed, to reduce the protocol's routing overhead. Third and most important is the route computation mechanism, which is integrated with a topology forecasting technique to construct up-to-date routes between the communication peers, aiming to achieve high delivery rate and increase the protocol robustness against the nodes' movement. FORTEL demonstrates higher performance as compared to other MANET's routing protocols, and it delivers up to 20% more packets than AODV and up to 60 % more than DSR and OLSR, while maintaining low levels of routing overhead and network delay at the same time. The effectiveness of the window update scheme is also discussed, and it proves to increase FORTEL's delivery rate by up to 30% as compared to the other update schemes. A common and frequently occurring phenomenon, in wireless networks, is the Hidden Terminal problem that significantly impacts the communication performance and the efficiency of the routing and MAC protocols. Beaconless routing approach in MANETs, which delivers data packets without prior knowledge of any sort `of information, suffers from packet duplication caused by the hidden nodes during the contention process. Moreover, the throughput of the IEEE MAC protocol decreases dramatically when the hidden terminal problem occurs. RTS/CTS mechanism fails to eliminate the problem and can further degrade the network's performance by introducing additional overhead. To tackle these challenges, this thesis presents two techniques, the Sender Suppression Algorithm and the Location-Aided MAC, where both rely on the nodes' position to eliminate packet duplication in the beaconless routing and improve the performance of the 802.11 MAC respectively. Both schemes are based on the concept of grouping the nodes into zones and assign different time delay to each one. According to the Sender Suppression Algorithm, the sender's forwarding area is divided into three zones, therefore, the local timer, set to define the time that the receiver has to wait before responding to the sender's transmission, is added to the assigned zone delay. Following the first response, the sender interferes and suppresses the receivers with active timer of. On the other hand, the Location-Aided MAC, essentially a hybrid MAC, combines the concepts of time division and carrier sensing. The radio range of the wireless receiver is partitioned into four zones with different zone delays assigned to each zone. Channel access within the zone is purely controlled by CSMA/CA protocol, while it is time-based amongst zones. The effectiveness of the proposed techniques is demonstrated through simulation tests. Location-Aided MAC considerably improves the network's throughput compared to CSMA/CA and RTS/CTS. However, remarkable results come when the proposed technique and the RTS/CTS are combined, which achieves up to 20% more throughput as compared to the standalone RTS/CTS. Finally, the thesis presents a novel link lifetime estimation method for greedy forwarding to compute the link duration between two nodes. Based on a newly introduced Stability-Aware Greedy (SAG) scheme, the proposed method incorporates the destination node in the computation process and thus has a significant advantage over the conventional method, which only considers the information of the nodes composing the link.EThOS - Electronic Theses Online ServiceGBUnited Kingdo