My FYP

Wireless Sensor Networks (WSN) consists of numerous sensor nodes which densely deployed in a spatially distributed region. It is a multi-hop ad hoc network system where each sensor is fitted with a small amount of processing, computing and communication capabilities. When each node is coordinated with the information from other nodes, they have the ability to measure the provided physical environment in great details or to execute a task with complex functions. Hence, a sensor network can be classified as a collection of sensor nodes that coordinate with each other to perform some specific actions.

Since each sensor node is equipped with an on-board processor, sensor nodes use their processing abilities to find out simple computations and transmit only the required data. Through this wireless communication, the sensor can sense, collect and process the objects in sensor region and send the data back to the user. There are many potential applications of sensor networks such as military, security, environmental and health related areas. Thus, many academe and industry pay more attention in this field because of its benefits in future.

Nowadays, WSN network has become more complex and in the large scales. The study of WSN is much challenging because it requires a deep knowledge of network simulation technology. Through the simulation, researches can study the wireless sensor network in the environment which can be controlled by observing the mutual function of the nodes caused by the disturbance or the noise. With the result, researches can improve the network success ratio and reduce the network maintenance works through the gained nodes details.

Basically, computer simulation, analyzing methods, and physical measurement are the three main techniques used for analyzing the performance of WSN. However, in WSN, they contain a lot of constrains, such as energy limitation, decentralized collaboration, and fault tolerance. These limitations cause many unresolved design and implementation problems, thus measurements are practically impossible. It appears that simulation is currently the primary feasible approach for analyzing the behaviors of sensor network and reducing the development lifetime.

Generally, WSN comprise of large number of nodes. To develop an excellent simulator, the following requirements should be followed:

1)    The simulation programs usually have a long debugging periods. Thus, the simulation software should emphasis on ability to trace and debug the simulation models to enhance researcher’s working efficiency and the error correction ability.

2)    Since WSN uses hierarchical structure, we need a large number of modules to construct models, the module relations must defined in hierarchical to built reusable components. This can reduce researcher’s work time and the usage of memory.

3)    WSN needs to integrate with other software to achieve the target. Thus, the software itself needs definition, customizable and open data interfaces to generate and process input and output files with commonly available software tools to allow embedding simulation models into larger applications. Embedding brings additional requirements about the memory management and reusability.

The objective of the project is to do simulation on WSN based on the routing protocol. Since each node in WSN is only powered by a battery, thus it has a limitation and will die due to energy loss. If the numbers of nodes die increases, it will gradually affect the performance of WSN. Therefore, by doing a simulation, we can decide which routing protocol suitable for the WSN devices so that it will work efficiently, save a lot of energy and last longer. The objective can be achieved by dividing the work into four stages:

1)    Studying how OMNET++ is used as simulator.

2)    Defining the structure of wireless sensor networks.

3)    Implementation of sensor network in the OMNET++ environment.

4)    Extension to simulate in specific applications.

In the first stage, we need to study how OMNET++ is used in programming and create some simple wireless network simulations, while in the second stage, we define the structure of wireless sensor networks and in the third stage, we implement OMNET++ by adding some components to use in the sensor network. Finally, our simulator is extended to simulate the specific applications.