Sensor Network Simulator Research Articles

Design and Implementation of Digital Sensor Simulator

With the rapid development of sensor technology recently, sensors have been applied to various fields for detecting object states, e.g. intelligent agriculture, intelligent power, intelligent city, the Internet of Things, etc., and have becoming more and more critical for dynamic data acquisition. Due to detection environment, detection technology, costs and other factors, access to actual sensors for developing or debugging a sensor application may cause additional costs and time. Meanwhile, testing new sensor applications and protocols needs appropriate feasible ways with low costs and short time. Therefore, it is fairly urgent for designing and developing a simulation environment of sensors and sensor applications. This paper parsed the general structure of digital sensors, and then designed domain-based high level architecture of digital sensor simulator. Finally, the prototype of digital sensor simulator was developed and demonstrated the proper performance. Results show that digital sensor simulator would provide an effective way for testing novel sensors and protocols and also play an important role for constituting sensor network simulation environment.

Enhancing the Simulation Speed of Sensor Network Applications by Asynchronization of Interrupt Service Routines

Sensor network simulations require high fidelity and timing accuracy to be used as an implementation and evaluation tool. The cycle-accurate and instruction-level simulator is the known solution for these purposes. However, this type of simulation incurs a high computation cost since it has to model not only the instruction level behavior but also the synchronization between multiple sensors for their causality. This paper presents a novel technique that exploits asynchronous simulations of interrupt service routines (ISR). We can avoid the synchronization overheads when the interrupt service routines are simulated without preemption. If the causality errors occur, we devise a rollback procedure to restore the original synchronized simulation. This concept can be extended to any instruction-level sensor network simulator. Evaluation results show our method can enhance the simulation speed up to 52% in the case of our experiments. For applications with longer interrupt service routines and smaller number of preemptions, the speedup becomes greater. In addition, our simulator is 2 to 11 times faster than the well-known sensor network simulator.

Adaptive Scheduling and Routing Scheme for Delay Guarantee in Wireless Sensor Networks

In wireless sensor networks (WSNs), periodical sleeping scheme on sensor nodes is an effective way to save energy. However, it will hinder the capability of the network to provide real-time data reporting due to relay node being sleep. Motivated by this, we propose an adaptive scheduling and routing scheme for guaranteeing dynamic end-to-end delay requirement while minimizing the energy consumption. First of all, we utilize an optimal wake-up scheduling algorithm to achieve the initial wake-up schedules and routes and design an adaptive adjustment algorithm. When the end-to-end delay requirement of a region changes, our proposed adaptive adjustment algorithm can locally adjust the wake-up schedules or the routing tables of the nodes which are the nearest ones to the source node, so as to minimize energy consumption and the impact on other regions while guaranteeing the new end-to-end delay requirement of the region. Through experiments in a real wireless sensor network and extensive simulations, we can get that the proposed scheme can conserve at least 20% energy consumption comparing to other existing adjustment algorithms, and its performance approaches that of the optimal solution.

Towards efficient dynamic surface gateway deployment for underwater network

In underwater acoustic sensor network, deploying multiple surface-level radio capable gateways is an efficient way to alleviate the burdens of high propagation delay and high error probability during transmission. However, the locations of gateways need to be carefully selected to maximize the benefit in a cost-effective way. In this paper, we present our formulation of the surface gateway deployment problem as an integer linear programming (ILP) and we solve the problem with heuristic approaches to provide a realtime solution for large scale deployment problems. By applying the proposed heuristic algorithms to a variety of deployment scenarios, we show that they are nearly optimal for practical cases, which opens the door for dynamic deployment. Therefore, we extend our solution to a dynamic case and propose a modified framework that integrates Aqua-sim, a NS2-based underwater wireless sensor network simulator. Our simulation result shows the benefits of dynamic gateway redeployment over static deployment.

Design Issues on Software Aspects and Simulation Tools for Wireless Sensor Networks

In this paper, various existing simulation environments for general purpose andspecific purpose WSNs are discussed. The features of number of different sensor network simulators and operating systemsare compared. We have presented an overview of the mostcommonly used operating systems that can be used in different approaches to address the common problems of WSNs . For different simulation environments there are different layer, componentsand protocols implemented so that it is difficult to compare them. When same protocol is simulated usingtwo different simulators still each protocol implementation differs, since their functionality is exactly not the same.Selection of simulator is purely based on the application, since each simulator has a varied range of performance depending on application.

Surface-level path loss modeling for sensor networks in flat and irregular terrain

Many wireless sensor network applications require sensor nodes to be deployed on the ground or other surfaces. However, there has been little effort to characterize the large- and small-scale path loss for surface-level radio communications. We present a comprehensive measurement of path loss and fading characteriztics for surface-level sensor nodes in the 400 MHz band in both flat and irregular outdoor terrain in an effort to improve the understanding of surface-level sensor network communications performance and to increase the accuracy of sensor network modeling and simulation. Based on our measurement results, we characterize the spatial small-scale area fading effects as a Rician distribution with a distance-dependent K-factor. We also propose a new semi-empirical path loss model for outdoor surface-level wireless sensor networks called the Surface-Level Irregular Terrain (SLIT) model. We verify our model by comparing measurement results with predicted values obtained from high-resolution digital elevation model (DEM) data and computer simulation for the 400 MHz and 2.4 GHz band. Finally, we discuss the impact of the SLIT model and demonstrate through simulation the effects when SLIT is used as the path loss model for existing sensor network protocols.

Petri net based evaluation of energy consumption in wireless sensor nodes

Wireless Sensor Networks have proven their capability to deal with problems where wide and hardly accessible areas need to be monitored. Among the other systems there are also sensor networks in which nodes can voluntarily modify their positions to better adapt to changes of monitored phenomenon. One of the major issues arising in these situations is the energy consumption: as all the movements affect the batteries lifetime, the life of a sensor can be extended by equipping the device with power generators that exploit renewable sources, albeit this solution does not always avoid a full battery discharge. In this paper a Fluid Stochastic Petri Net modelling framework is presented to provide a wide evaluation of all the factors that contribute to the energy dissipation in mobile wireless sensor nodes. The framework allows the generation of extensible and composable models capable to evaluate the energy consumption due to sensing, communication and movement functions as well as the impact of power saving mechanisms on the energetical balance of the node. The approach is applied to a marine sensing problem and is validated by comparing the model analysis results with experimental results achieved through an existing off-the-shelf sensor network simulator.

Adequacy of wireless sensor network models in simulation environments

The paper gives the analysis of existing tools for wireless sensor networks (WSN) simulation and verification of the obtained models. The objective of the research is verification of the WSN model obtained in simulation environment OMNET ++. Each of the analyzed simulation systems of wireless sensor networks allows: -increasing the WSN development efficiency; -conducting an experiment without real deployment of sensor network; -carrying out researches of WSN; -significant costs reduction for network development and deployment. The model adequacy depends on the purpose of modeling and accepted criteria. WSN simulation models development based on the simulation system OMNET++ provides adequate models. This is confirmed by the obtained results

A Simple Energy Harvesting Algorithm for Wireless Sensor Networks

Harvesting energy from the environment is essential for many applications to slow down the deterioration of energy of the devices in sensor networks and in general, the network itself. Energy from the environment is an inexhaustible supply which, if properly managed and harvested from the sources, can allow the system to last for a longer period - more than the expected lifetime at the time of deployment, or even last indefinitely. The goal of this study is to develop a simple algorithm for ns-2 to simulate energy harvesting in wireless sensor network simulations. The algorithm is implemented in the energy module of the simulator. Energy harvesting algorithms have not yet been developed for ns-2. This study will greatly contribute to the existing knowledge of simulating wireless sensor networks with energy harvesting capabilities in ns-2. This paper will also serve as a basis for future research papers that make use of energy harvesting.

A mobility model for shopping mall environments founded on real traces

Simulations of mobile ad-hoc, sensor, and mesh networks strongly rely on mobility models because they have a major influence on the performance of protocols. Results obtained with an unrealistic model may not reflect the true performance of protocols, applications and algorithms in real environments. In this paper, we present a mobility model for shopping mall environments based on real traces. Such environments offer all of the elements required to build large-scale people-centric ad-hoc networks. In many cases, shopping malls are tens of thousands of square metres in area and crowded much of the time. We ran a field trial to collect Bluetooth contact data from shop employees and clerks in a shopping mall over six days. We analysed the collected contact traces to guide the design of our Shopping Mall mobility model. Unlike the majority of existing synthetic mobility models our Shopping Mall mobility model captures heterogeneous behaviour of nodes and several different mobility characteristics at a lower level of abstraction. We show that our synthetic mobility model produces contact traces distributions which approximate those of the collected traces.

ATLeS-SN

As wireless sensor network platforms become increasingly more complex to design and optimize due to the multitude of interdependent parameters that must be considered, computer simulations have emerged as the primary solution to feasibly analyze the long-term effects of design changes within a deployed system. Although several successful wireless sensor network simulators have already been developed, to our knowledge, none provide the modularity necessary to model sensor nodes and/or environmental components at differing levels of abstraction. In this paper, we present the Arizona Transaction-Level Simulator for Sensor Networks (ATLeS-SN), which by virtue of its implementation language--SystemC--allows application developers to easily specify interchangeable component models in order to achieve the desired simulation correctness, performance, and scalability. We provide an overview of our proposed simulation framework and highlight its benefits using a sound ranging application.

Effect of Channel Fading on the Performance of Wireless Ad Hoc Network Routing Protocols

In this paper the application spectrum of wireless ad hoc network is a typical battle field monitoring system for the public safety purpose and military sector where the sensor network simulator architecture is used to provide support for sensing capabilities in network nodes for different mobility conditions. Rayleigh and Rician fading (K=3) model is used for the effect of channel fading in the network scenario. The channel fading incurs extra network overhead in the PHY, MAC and Network layer. A comprehensive study on the performance of ad hoc network routing protocols under realistic network scenarios with the effect of channel fading models is presented.

Liowsn Project: An Operating System Remastered for Works with Simulation of Wireless Sensor Networks

Since the last decade, the area of Wireless Sensor Networks (WSN) is a field search on the rise. Due to its high mobility and scalability in several areas, acting on functions of sensing, monitoring, tracking, control and maintenance, WSNs are increasingly attracting researchers for the study. With the advent of computer simulations, it has been eliminated, in part by the necessity of obtaining real sensors, which because of its implementation cost, eventually disabling the initial analysis and further tests with these networks. Considering that most of these simulator programs are native from GNU/Linux, expertises are needed to implement these tools in the operating system, which can be a problem. This paper presents the Liowsn project, which is a GNU/Linux operating system remastered with several classic tools of literature already installed and configured, and it has been proposed in order to achieve a higher speed in the implementation process of the simulation environment to study this type of network.

EAR: An Energy and Activity-Aware Routing Protocol for Wireless Sensor Networks in Smart Environments

Sensor network, unlike traditional communication network, is deeply embedded in physical environments and its operation is mainly driven by the event activities in the environment. In long-term operations, the event activities usually show certain patterns which can be learned and exploited to optimize network design. However, this has been underexplored in the literature. One work related to this is using ATPG for radio duty cycling ([1]). In this paper we present a novel Energy and Activity aware Routing (EAR) protocol for sensor networks. As a case study, we have evaluated EAR with the data trace of real Smart Environments. In EAR an Activity Transition Probability Graph (ATPG) is learned and built from the event activity patterns. EAR is an online routing protocol, which chooses the next-hop relay node by utilizing: activity pattern information in the ATPG graph and a novel index of energy balance in the network. EAR extends network lifetime by maintaining an energy balance across the nodes in the network, while meeting application performance with desired throughput and low data delivery latency. We theoretically prove that: (a) the network throughput with EAR achieves a competitive ratio (i.e., the ratio of the performance of any offline algorithm that has knowledge of all past and future packet arrivals to the performance of our online algorithm) which is asymptotically optimal, and (b) EAR achieves a lower bound in network lifetime. Extensive experimental results from: (a) 82 node Motelab sensor network testbed [2] and (b) varying size network (20-100) in sensor network simulator TOSSIM, validate that EAR outperforms the existing methods both in terms of network performance (network lifetime, network energy consumption) and application performance (low latency, desired throughput) for an energy-constrained sensor network.

Desynchronization with an artificial force field for wireless networks

Desynchronization is useful for scheduling nodes to perform tasks at different time. This property is desirable for resource sharing, TDMA scheduling, and collision avoiding. Inspired by robotic circular formation, we propose DWARF (Desynchronization With an ARtificial Force field), a novel technique for desynchronization in wireless networks. Each neighboring node has artificial forces to repel other nodes to perform tasks at different time phases. Nodes with closer time phases have stronger forces to repel each other in the time domain. Each node adjusts its time phase proportionally to its received forces. Once the received forces are balanced, nodes are desynchronized. We evaluate our implementation of DWARF on TOSSIM, a simulator for wireless sensor networks. The simulation results indicate that DWARF incurs significantly lower desynchronization error and scales much better than existing approaches.

Supporting dynamic simulations with Simulation Modeling Architecture (SiMA): a Discrete Event System Specification-based modeling and simulation framework

In this paper, we present our approach to introduce dynamism support to simulation environments, which adopts a Discrete Event System Specification (DEVS)-based modeling and simulation approach and builds upon previous work on Simulation Modeling Architecture (SiMA), a DEVS-based simulation framework developed at TUBITAK UEKAE. In the relevant literature there are already proposed solutions to the dynamism support problem. One particular contribution offered in this study over previous approaches is the systematic framework support for post-structural-change state synchronization among models with related couplings, in a way that benefits from the strongly typed execution environment SiMA provides. In addition to introducing theoretical extensions to basic SiMA, we report the results of performance measurements to illustrate the added value of dynamism extensions over the basic version, using a sample wireless sensor network simulation.

MSNS: mobile sensor network simulator for area coverage and obstacle avoidance based on GML

Abstract A mobile sensor network is a distributed collection of sensors, each of which has sensing, computation, communication, and locomotion capabilities. In particular, locomotion facilitates the ability to self-deployment. In such a network of self-deployable mobile sensors, it is difficult to evaluate the effectiveness of mobile sensor network deployment in a given target area because we cannot predict the coverage rate for the target area. The coverage rate will be changed due to the number of sensor required in the target area, connectivity degree to be maintained and unknown obstacles. In this article, we develop mobile sensor network simulator (MSNS) in order to visualize (1) coverage secured by mobile sensors and (2) avoidance of obstacle objects (building, road and wall, and so on) on the real map drawn by GML (Geography Markup Language). From a user, MSNS receives the number of mobile sensor nodes, connectivity degree, sensor node's sensing range, communication range, and supersonic wave range. And then it visualizes the location information of sensor nodes, connectivity degree, and sensing coverage, all of which change with simulation time. Thereby we can estimate how many nodes are required in a given target area, and also calculate coverage rate of the target area in advance to the real deployment of mobile sensors.

BeeSensor: An energy-efficient and scalable routing protocol for wireless sensor networks

Design and development of power-aware, scalable and performance-efficient routing protocols for wireless sensor networks (WSNs) is an active area of research. In this paper, we show that insect-colonies-based-intelligence – commonly referred to as Swarm Intelligence (SI) – serves as an ideal model for developing routing protocols for WSNs because they consist of minimalist, autonomous individuals that through local interactions self-organize to produce system-level behaviors that show life-long adaptivity to changes and perturbations in an external environment. In this paper, we propose bee-inspired BeeSensor protocol that is energy-aware, scalable and efficient. The important contribution of this work is a three phase protocol design strategy: (1) we first take inspiration from biological systems to develop a distributed, decentralized and simple routing protocol, (2) we formally model important performance metrics of our protocol to get an analytic insight into its behavior, and (3) we improve our protocol on the basis of our analysis in phase 2. We then evaluate its performance in a sensor network simulator. The results of our experiments demonstrate the utility of this three phase protocol engineering, which helped BeeSensor in achieving the best performance with the least communication and processing costs – two main sources of energy consumption in sensor networks – as compared to other SI based WSN routing protocols.

Comparative Performance Evaluation of MAC Layer Protocols for Underwater Wireless Sensor Networks

Underwater Acoustic Wireless Sensor Networks (UAWSN) use acoustic communication for transmitting data. High bit error rate, long propagation delay and limited bandwidth in underwater harsh environment are big issues for designing wireless sensor networks for many applications including ocean monitoring. Another consideration in UWASN is energy constraint. Similar to other wireless sensor networks the design process of energy and efficient bandwidth and also propagation-delay-aware MAC protocols are great challenges in UWASN. In this paper, the performance of three underwater MAC protocols for underwater environment, R-MAC, Slotted FAMA and UWAN-MAC are evaluated. Throughput, energy consumption and packet drop rate are those parameters which are considered for evaluating their performances. These protocols are implemented in Aqua-Sim, an NS-2 based simulator for underwater sensor networks. The simulation results show the effectiveness of the proposed method.

Formula omitted]: Activity-aware sensor network in smart environments

A sensor network, unlike a traditional communication network, provides high degree of visibility into environmental physical processes. Therefore its operation is driven by the activities in the environment. In long-term operations, these activities usually show certain patterns which can be learned and utilized to optimize network design. However, this has been almost unexplored in the literature. In this paper we present the design and validation of ActiSen system, an activity-aware sensor network in smart environments. ActiSen consists of three components: activity-aware sensing, activity-aware radio duty-cycling, and activity-aware and energy balanced routing. Experimental results from real testbed experiments and sensor network simulator TOSSIM validate that the activity-aware design of ActiSen outperforms existing methods in terms of resource utilization (energy efficiency, lifetime etc.) and system performance (data delivery throughput, delivery latency etc.).