Localized Minimum Spanning Tree Based Multicast Routing with Energy-Efficient Guaranteed Delivery in Ad Hoc and Sensor Networks

We present a minimum spanning tree based energy aware multicast protocol (MSTEAM), which is a localized geographic multicast routing scheme designed for ad hoc and sensor networks. It uses locally-built minimum spanning trees (MST) as an efficient approximation of the optimal multicasting backbone. Using a MST is highly relevant in the context of dynamic wireless networks since its computation has a low time complexity (O(n log n)). Moreover, our protocol is fully localized and requires nodes to gather information only on 1-hop neighbors, which is common assumption in existing work. In MSTEAM, a message split occurs when the MST over the current node and the set of destinations has multiple edges originated at the current node. Destinations spanned by each of these edges are grouped together, and for each of these subsets the best neighbor is selected as the next hop. This selection is based on a cost over progress metric, where the progress is approximated by subtracting the weight of the MST over a given neighbor and the subset of destinations to the weight of the MST over the current node and the subset of destinations. Since such greedy localized scheme may lead the message to a void area (i.e., there is no neighbor providing positive progress toward the destinations), we also propose a completely new multicast generalization of the well-know face recovery mechanism. We provide a theoretical analysis proving that MSTEAM is loop-free and always achieves delivery of the multicast message, as long as a path exists between the source node and the destinations. Our experimental results demonstrate that MSTEAM is highly energy-efficient, outperforms the best existing localized multicast scheme and is almost as efficient as a centralized scheme in high densities

Greedy Routing Recovery Using Controlled Mobility in Wireless Sensor Networks

International audienceOne of the most current routing families in wireless sensor networks is geographic routing. Using nodes location, they generally ap- ply a greedy routing that makes a sensor forward data to route to one of its neighbors in the forwarding direction of the destination. If this greedy step fails, the routing protocol triggers a recovery mechanism. Such re- covery mechanisms are mainly based on graph planarization and face traversal or on a tree construction. Nevertheless real-world network pla- narization is very difficult due to the dynamic nature of wireless links and trees are not so robust in such dynamic environments. Recovery steps generally provoke huge energy overhead with possibly long inefficient paths. In this paper, we propose to take advantage of the introduction of controlled mobility to reduce the triggering of a recovery process. We propose Greedy Routing Recovery (GRR) routing protocol. GRR en- hances greedy routing energy efficiency as it adapts network topology to the network activity. Furthermore GRR uses controlled mobility to relocate nodes in order to restore greedy and reduce energy consuming recovery step triggering. Simulations demonstrate that GRR successfully bypasses topology holes in more than 72% of network topologies avoid- ing calling to expensive recovery steps and reducing energy consumption while preserving network connectivity

Surveying Position Based Routing Protocols for Wireless Sensor and Ad-hoc Networks

A focus of the scientific community is to design network oriented position-based routing protocols and this has resulted in a very high number of algorithms, different in approach and performance and each suited only to particular applications. However, though numerous, very few position-based algorithms have actually been adopted for commercial purposes. This article is a survey of almost 50 position-based routing protocols and it comes as an aid in the implementation of this type of routing in various applications which may need to consider the advantages and pitfalls of position-based routing. An emphasis is made on geographic routing, whose notion is clarified as a more restrictive and more efficient type of position-based routing. The protocols are therefore divided into geographic and non-geographic routing protocols and each is characterized according to a number of network design issues and presented in a comparative manner from multiple points of view. The main requirements of current general applications are also studied and, depending on these, the survey proposes a number of protocols for use in particular application areas. This aims to help both researchers and potential users assess and choose the protocol best suited to their interest

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

MFACE: A Multicast Backbone-Assisted Face Traversal Algorithm for Arbitrary Planar Ad Hoc and Sensor Network Topologies

Face is a well-known localized routing protocol for ad hoc and sensor networks which guarantees delivery of the message as long as a path exists between the source and the destination. This is achieved by employing a left/right hand rule to route the message along the faces of a planar topology. Although face was developed for the unicast case, it has recently been used in combination with multicasting protocols, where there are multiple destinations. Some of the proposed solutions handle each destination separately and lead thus to increased energy consumption. Extensions of face recovery to the multicast case described so far are either limited to certain planar graphs or do not provide delivery guarantees. A recently described scheme employs multicast face recovery based on a so called multicast backbone. A multicast backbone is a Euclidean spanning tree which contains at least the source and the destination nodes. The idea of backbone assisted routing it to follow the edges of the backbone in order to deliver a multicast message to all spanned destination nodes. The existing backbone face routing scheme is however limited to a certain planar graph type and a certain backbone construction. One of the key aspects of the multicast face algorithm MFACE we propose in this work is that it may be applied on top of any planar topology. Moreover, our solution may be used as a generic framework since it is able to work with any arbitrary multicast backbone. In MFACE, any edge of the backbone originated at the source node will generate a new copy of the message which will be routed toward the set of destination nodes spanned by the corresponding edge. Whenever the message arrives at a face edge intersected by a backbone edge different from the initial edge, the message is split into two copies, both handling a disjoint subset of the multicast destinations which are defined by splitting the multicast backbone at that intersection point

A Distributed Geo-Routing Algorithm for Wireless Sensor Networks

Geographic wireless sensor networks use position information for greedy routing. Greedy routing works well in dense networks, whereas in sparse networks it may fail and require a recovery algorithm. Recovery algorithms help the packet to get out of the communication void. However, these algorithms are generally costly for resource constrained position-based wireless sensor networks (WSNs). In this paper, we propose a void avoidance algorithm (VAA), a novel idea based on upgrading virtual distance. VAA allows wireless sensor nodes to remove all stuck nodes by transforming the routing graph and forwarding packets using only greedy routing. In VAA, the stuck node upgrades distance unless it finds a next hop node that is closer to the destination than it is. VAA guarantees packet delivery if there is a topologically valid path. Further, it is completely distributed, immediately responds to node failure or topology changes and does not require planarization of the network. NS-2 is used to evaluate the performance and correctness of VAA and we compare its performance to other protocols. Simulations show our proposed algorithm consumes less energy, has an efficient path and substantially less control overheads