OPNET is a network simulation tool which can simulate various elements in a network. It is able to analyze traffics and even can simulate security events recently. System designers can identify vulnerabilities or find an efficient algorithm/protocol that could reduce costs if simulations are performed prior to actual implementation/construction of a large-scale system. Thus, this chapter includes the method of simulating a PLC-system, designing a PLC-based vertical fish farm and an expandable simulation test bed with which students or researchers will be able simulate their implementation methods. With these methods, it will be possible to perform large-scale simulations.
Top1. Introduction
In recent years, the systems related to the Vertical Farm and Internet of Things (IoT) are being studied widely. Although there are some useful technological means (e.g., RS-232, Zigbee and Wifi) to establish these systems, we are concentrating our book on the Power Line Communication technology. Communications utilizing existing power line are generally called the Power Line Communication and this technology uses high-frequency signals to transmit or store data through power lines, during which frequency signals are separated with the dedicated power line modem(s) as low or high frequency signals before reaching to a terminal device. Two different speed levels are available for the Power Line Communications: high-speed and low-speed. The former uses frequency bands between 0.5 and 30MHz reaching speeds of 14Mbps to 1Gbps (as of 2015) while the latter relies on the bands between 10 and 450KHz achieving a maximum speed of 9.6Kbps normally used for electric equipment or devices. In fact, the Power Line Communication media are originally designed for power transmissions.
It’s been assumed that the channel characteristics of Power Line Communications are unsuitable for a data communication purpose due to rather heavy noises and serious signal attenuation. One way to improve reliability of the Power Line Communication is to enhance its physical layer associated with channel estimation and selection, filtering design, power distribution or others.
Meanwhile, China is one of the major producers of aquaculture products and their production volume is the largest among these countries. In this country, the aquafarms distant from the cities are attempting to surmount high costs of internet installation by constructing the internet network through existing power lines. Since the problem of silent node often appears in the long-distance Power Line Communications, this book targeted the fishing villages where the internet service is not available.
The Power Line Communication technology is being applied to the home-network construction or factory automation nowadays but due to the improvements made in transmission speed and stability achieved with recent digital power line technology, its applicability is still growing and getting much attentions (Tsuzuki, Areni & Lehnert, 2012). One of the main reasons for such interest is because of the feasibility of low-cost implementation using existing power line distribution and smart meter networks. Meanwhile, the situation-specific simulations and modeling of Power Line Communication-based solution will be needed to implement Power Line Communication system in a noise-filled channel environment to improve both the stability and reliability. Although many studies have been carried out for modeling Power Line Communication’s physical characteristics with a variety of simulation tools so far, they many more are yet to come (Huh & Seo, 2014; Gao et al., 2008; Sabolic, 2003).
Figure 1. The mechanism of PLC and PLC Slient node problem
The Figure 1 shows a structure where data is sent through power line by installing two Power Line Communication adapters in the wall outlet. Using the power line installed at the time of construction, the electricity is supplied with the low frequency band of 60Hz and the data will be transmitted with the remaining high frequency bands available. New product lines of adapters with the maximum speed of 1Gb/bps have been released recently.
The Power Line Communication technology is increasingly accepted in the fields of building automation, security control and others as it enables convenient and cost-effective communication system. One such system is the Automatic Meter Reading (AMR) system where meter readings can be sent over to a power company through the power lines available in most of the industrial and public sectors. Not requiring separate or additional infrastructures is a very strong advantage and quite suitable for establishing the low-cost AMR network.