DEVELOPMENT OF WIRELESS SENSOR NETWORK TESTBED

1.1 Introduction

Wireless network is a system that provides the agility needed to adapt to different teaching methods, research requirements, and student needs. Wireless sensor network testing can be a challenging task. It takes several iterations to re-program dozens of nodes, place them in a way that creates intriguing radio architecture, and instrument them to gather performance and debugging information before deploying a network into a real-world setting (Levis et al., 2003; Shnayder et al., 2004). Since the introduction of wireless networks, a great deal has changed in the world. Wireless networks have advanced significantly, and their uses have grown. These days, mobile phones are a typical instrument that individuals utilize for communication and information sharing. Large wireless network systems require them as a necessary component. The wireless interface of an access station can provide wireless coverage for a small geographical area approximately 50 meters in diameter.

As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Limitation of the study and Definition of technical terms.

1.2 Background of Study

Wireless networks have made location easier in recent years, making location-based services available to customers. Many measures, usually available during regular network and terminal activities, mainly for resource management and synchronization, can be utilized to pinpoint the user's position. This research will focus on resource sharing on a dedicated network due to the vast array of uses that wireless networks have. ALOHAnet, the world's first wireless computer communication network, was developed by University of Hawaii professor Norman Abramson using low-cost ham-like radios.

The network went online in 1971. The system consisted of seven computers located on four different islands connected by phone lines to the central computer on Oahu Island. WLAN hardware was first so expensive that it was limited to use as a cabling-difficult or impossible alternative to wired LAN in locations. Initially, industry-specific solutions and proprietary protocols were used in development; however, by the end of the 1990s, these were superseded by standards, mainly the different IEEE 802.11 versions (found in products bearing the Wi-Fi marquee). The faster 54 Mbit/s 802.11a (5 GHz) and 802.11g (2.4 GHz) standards make it even less likely that HiperLAN/2, an alternative ATM-like 5 GHz standardized technology, will ever succeed in the market. HiperLAN/2 has not yet proven successful in anything.

Eighty-two was enhanced with 802.11n in 2009. A maximum data transfer rate of 600 Mbit/s is achieved while operating in the 2.4 GHz and 5 GHz bands. Known as dualband, the majority of modern routers can make use of both wireless bands. In addition to being shared by Bluetooth devices and microwave ovens, the crowded 2.4 GHz band can now be avoided for data communications. An increased number of devices can share the space in the 5 GHz band due to its wider bandwidth and additional channels compared to the 2.4 GHz band. Some regions do not have access to every channel.

It is possible to gradually grow the network by adding more devices or putting complex settings into place. In addition to offering substantial installation cost savings, wireless sensor networks can adapt quickly to changing circumstances. Network topologies can alter, and adaptation mechanisms can cause the network to respond by changing between drastically different modes of operation. For example, an embedded network in a chemical plant used for leak monitoring could be reconfigured to follow the movement of hazardous gases and find the leak's source. The safest emergency escape path may then be disclosed to staff by the network.

The potential that arise from the integration of low-power communication, sensing, energy storage, and computation are only partially realized by current wireless systems. in the next generation of the internet, wireless connectivity will play an increasingly significant role, according to recent innovations and market trends toward portable computing and communication devices. The large-scale embedded computer device adoption is primarily dependent on the performance of short-range wireless sensor networks. At the periphery of the internet, wireless, mobile and sensor network situations should increase quickly.

An instrument to propel their future ideas is needed by researchers in order to contribute to the development of the next generation internet, which will comprise wireless and sensor network devices. Although they require a facility to assess them, researchers are looking into next-generation network architecture and protocols. Measurements, high-fidelity settings, or analytical modeling can all be used for the evaluation. The best understanding of the impacts of different parameters and how they interact comes from analytical modeling. Despite its versatility, analytical modeling is not as commonly utilized as simulation or measurements due to its complexity. Analytical modeling's oversimplified mathematical modeling methods, which fail to account for sensor network irregularities, represent another drawback.

1.3 Statement of Problem

Investigation revealed that building an environmental physical quantity monitoring system will help us manage and maintain the environment intelligently, taking into account the effects of environmental quantities on both nature and humans. A variety of physical circumstances should be supported by this system. Not requiring excavation or the construction of overhead structures, it should be inexpensive, simple to install, and require little upkeep.

The goal of our physical quantity monitoring system construction is to minimize or eliminate human error in readings. Therefore, the foundation of our efforts is the reporting of temperature, humidity, light intensity, and gases (smoke).

The testbed will be controlled by PC-end with different commands which can collect data from all sensor nodes easily and report failure or abnormity to users in time.

1.4 Aim / Purpose of the Study

The aim of the study is to develop a wireless sensor network (WSN) testbed for realization of an environmental condition monitoring system.

1.5 Objectives of the Study

In achieving the above stated aim, the following specific objectives were laid out as follows:

1. To implement the designed sensory node that measures different environmental quantities selected;
2. To design a WSN based environmental monitoring system;
3. To review the existing WSN testbeds with their respective goals; and
4. To identify the components to be used for the design of the sensory nodes.

1.6 Significance of Study

The primary use of wireless sensor networks is in habitat and environmental monitoring, where a large number of sensor nodes collect data and forward it to one or more sink nodes. They are unable to interact directly with the sink since all of these nodes are often dispersed over a large area. Because of this, we intend to create two prototypes that will communicate via a receiver that needs to be built for efficient environmental study and monitoring.

The documentation of the proposed system will be of immense benefit to other researchers who intend to know more on this study and can also be used by non-researchers to build more on their research work. This study contributes to knowledge and could serve as a guide for other study.

1.7 Scope of Study

The scope of the research is focused on the Development of Wireless Sensor Network Testbed. The proposed solution of this project is limited to two nodes and a server. The two nodes can communicate with the server by sending signal to the server as well as receiving processed signal from the server. The transmitter can only transmit through a distance ranging from 90m to 110m.

The two nodes are arranged using star topology network in which the signal sent from each node is being transmitted straight to the server and reply from the server can be received from the node from which the signal is received. The design is to be modelled and simulated for measuring physical environmental quantities using WSN.

1.8 Limitations of the Study

During the course of this study, many things militated against its completion, some of which are:

1. Time Constraint:The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
2. Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet).

1.9 Definition of Terms

Library:

This entails the use of several textbooks, journals, past projects that have discussed previously the subject matters and have shed light to the subject.

Internet Browsing:

This requires surfing through various websites to get latest information and insight into the project work.

Field Survey:

This includes preliminary and reconnaissance survey of the research area to get basic information about the area for data collection.

Laboratory works:

This has to do with circuitry design, storage, querying and system analysis.

Test:

This involves the implementation of the design and testing it for data collection.

Router:

It is a specialized network device that determines the next network point to which to forward a data packet toward its destination.

Internet Protocol Address (IP Address):

It is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication.

An IP address serves two principal functions: host or network interface identification and location addressing. Its role has been characterized as follows: “A name indicates what we seek. An address indicates where it is. A route indicates how to get there.