04-06-2012, 12:16 PM
Simulating Wireless Sensor Networks with OMNeT++
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Abstract:
Wireless sensor networks have the potential to become significant subsystems of engineering applications. Before relegating important and safety-critical tasks to such subsystems, it is necessary to understand the dynamic behavior of these subsystems in simulation environments. There is an urgent need to develop simulation platforms that are useful to explore both the networking issues and the distributed computing aspects of wireless sensor networks.
Introduction
Wireless Sensor Networks (WSN) [2] comprises of numerous tiny sensors that are deployed in spatially distributed terrain. These sensors are endowed with small amount of computing and communication capability and can be deployed in ways that wired sensor systems couldn’t be deployed. For example, sensors can be deployed in environments that are inaccessible for humans or sensor networks can be deployed in environments that are changing such as a chemical cloud. Despite the prolific conceptualization of sensor networks as being useful for large-scale military applications, the reality is that the best migration path for sensor networks research into non-academic applications is via integration with
existing engineering applications infrastructure. For example, sensor networks have the potential to offer fresh solutions to fault diagnosis, health monitoring and innovative human-machine interaction paradigms.
Currently available Simulators
ns2 is a well-established discrete event simulator that provides extensive support for simulating TCP/IP, routing and multicast protocols over wired and wireless networks [4]. Radio propagation model based on two ray ground reflection approximation and a shared media model in the physical layer, an IEEE 802.11 MAC protocol in the link layer and an implementation of dynamic source routing for the network layer were developed in the Monarch project [8].
The OMNeT++ Framework
Objective Modular Network Test-bed in C++ (OMNeT++) is a public-source, component-based, modular simulation framework [16]. It is has been used to simulate communication networks and other distributed systems. The OMNeT++ model is a collection of hierarchically nested modules as shown in Figure 1. The top-level module is also called the System Module or Network. This module contains one or more sub-modules each of which could contain other sub-modules. The modules can be nested to any depth and hence it is possible to capture complex system models in OMNeT++. Modules are distinguished as being either simple or compound. A simple module is associated with a C++ file that supplies the desired behaviors that encapsulate algorithms. Simple modules form the lowest level of the module hierarchy. Users implement simple modules in C++ using the OMNeT++ simulation class library.