A Tabu Search WSN Deployment Method for Monitoring Geographically Irregular Distributed Events

In this paper, we address the Wireless Sensor Network (WSN) deployment issue. We assume that the observed area is characterized by the geographical irregularity of the sensed events. Formally, we consider that each point in the deployment area is associated a differentiated detection probability threshold, which must be satisfied by our deployment method. Our resulting WSN deployment problem is formulated as a Multi-Objectives Optimization problem, which seeks to reduce the gap between the generated events detection probabilities and the required thresholds while minimizing the number of deployed sensors. To overcome the computational complexity of an exact resolution, we propose an original pseudo-random approach based on the Tabu Search heuristic. Simulations show that our proposal achieves better performances than several other approaches proposed in the literature. In the last part of this paper, we generalize the deployment problem by including the wireless communication network connectivity constraint. Thus, we extend our proposal to ensure that the resulting WSN topology is connected even if a sensor communication range takes small values

VNR Algorithm: A Greedy Approach For Virtual Networks Reconfigurations

6 pagesInternational audienceIn this paper we address the problem of virtual network reconfiguration. In our previous work on virtual network embedding strategies, we found that most virtual network rejections were caused by bottlenecked substrate links while peak resource use is equal to 18%. These observations lead us to propose a new greedy Virtual Network Reconfiguration algorithm, VNR. The main aim of our proposal is to 'tidy up' substrate network in order to minimise the number of overloaded substrate links, while also reducing the cost of reconfiguration. We compare our proposal with the related reconfiguration strategy VNA-Periodic, both of them are incorporated in the best existing embedding strategies VNE-AC and VNE-Greedy in terms of rejection rate. The results obtained show that VNR outperforms VNA-Periodic. Indeed, our research shows that the performances of VNR do not depend on the virtual network embedding strategy. Moreover, VNR minimises the rejection rate of virtual network requests by at least ' 83% while the cost of reconfiguration is lower than with VNA-Periodic

Architecture of low duty-cycle mechanisms

We describe the principles of low duty WSN architectures and we summarize the main WSN asynchronous MAC low duty-cycle schemes found in the literature. They are mainly two schemes, the first technique is sender-oriented and the second technique is receiver oriented. We explain how MAC low duty-cycle schemes and opportunistic routing algorithms can be combined in cross-layer approach. We propose two low duty WSN architectures: one is based on B-MAC (Sender-oriented), the second on RI-MAC (Receiver-oriented). We depict several variants for each cross-layer scheme. Depending on the transmission range, we evaluate the average i) packet delivery probability, ii) delay at each hop, iii) number of hops to reach the sink and iv) end-to-end delivery delay. We compare the simulation results, for each scheme, with those obtained by a simple analytical model using a Poisson point process. We study the energy consumed when no event is detected and the additional energy to convey a packet to the sink. We show that the gain in energy obtained with a low duty-cycle is very significant

A New Opportunistic Routing Scheme in Low Duty-Cycle WSNs for Monitoring Infrequent Events

We address opportunistic routing in low-duty cycle wireless sensor networks. A low duty-cycle consists in alternating active and sleep cycles asynchronously in order to save energy. In multihop networks, such a design must take an opportunistic approach in order to cope with the unpredictable appearance of wireless links. In fact, topology-based routing approaches are ineffective in this context. Our main objective is to maximize the network lifespan while guaranteeing i) the routing of packets to the sink and ii) acceptable end-to-end delays. We propose a new geographical opportunistic cross-layer scheme based on an asynchronous sender-oriented MAC protocol. The proposal sets the priority of selecting the next hop, among all potential candidates, according to its closeness to the sink. The next hop is elected through a selection process based on signalling bursts. The performance evaluation of our proposal is carried out both by an analytical model and simulations. The approach is evaluated in terms of i) probability of packet delivery to the sink, ii) number of hops per path and iii) end-to-end packet delay from the source to the sink

A Mesh-Based Sensors Deployment Method For Water Quality Monitoring

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A gradient approach for differentiated wireless sensor network deployment

International audienceIn this paper, we propose a new sensor deployment strategy by considering both a probabilistic sensor detection model and a monitored area with geographical irregularity requirement of the sensed events. In this case, each point in the deployment field needs a specific minimum guarantee in event detection probability. The main objective is to find the minimum number of senors and their positions, in order to guarantee the requirement event detection threshold. Thus, we propose a new scalable deployment strategy based on virtual forces. The fundamental idea of our proposal is to adjust the number and the position of sensors according to virtual forces that must be computed for each sensor. The performance evaluation shows that our proposal obtained the best results compared to several other sensor deployment strategies founded in the literature

Heuristic Deployment to Achieve Both Differentiated Detection and Connectivity in WSN

International audienceIn this paper, we extend the differentiated deployment method which we have proposed in our previous paper by adding the connectivity constraint. We assume a fixed communication ray and a probabilistic detection model. We also consider that to each point in the deployment area is associated a detection probability threshold, which must be satisfied by our deployment method. Finally, we suppose that the detection probabilities thresholds of the area are geographically nonuniformly distributed. Our differentiated deployment problem is modeled as multi-objectives optimization problem, which we resolve using our proposed Tabu Search-based algorithm. A comparison is made with the methods found in the literature. The performances obtained by our method are much better in term of required number of sensors, generated detection probabilities, while ensuring the network connectivity

Multi-Objective WSN Deployment: Quality of Monitoring, Connectivity and Lifetime

International audienceIn this paper, we will address a WSN deployment problem. The main objectives are i) reduce the cost of deployment, ii) ensure the requested event detection probabilities, iii) guarantee the network connectivity, and iv) maximize the lifetime of the network. We will formalize the problem as multi-objective combinatorial optimization problem. To resolve the problem, we will propose a new deployment algorithm named MODA. It will be based on evolutionary and neighborhood search algorithms. The obtained results are better than the deployment strategies found in the literature

Deployment in Wireless Sensor Networks

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Potential Field Approach to Ensure Connectivity and Differentiated Detection in WSN Deployment

International audienceThis paper addresses the issue of wireless sensor network (WSN) deployment. We investigate this problem in the case where the monitored area is characterized by a geographical irregularity of the sensed events. Precisely, we consider that each point of the deployment area requires a minimum threshold guarantee on the event detection probability. Our proposed scalable deployment method, named potential field-based deployment algorithm (PFDA), is based on the potential field and the virtual force approaches. Our proposal is able to (1) satisfy the required event detection probability threshold for each point, in a large-scale area, while minimizing the number of deployed sensors and (2) to ensure the network connectivity. The results and evaluation analysis show that PFDA outperforms the other strategies proposed in literatur