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Wireless networks make IOT happen

Wireless networks make IOT happened.
Okay, the last one (example), we look at the RFID. Probably lots of people here heard about the RFID. It represents the radio frequency identification. You see the words “identification.” Again, it is used to identify devices. That means if we have devices attached with RFID, it will be traceable. It will be uniquely traceable.
The first figure represents the basic operational principle of RFID. You can see to the left we have so-called the RFID tag. Basically, this is the small devices containing data. If we have sensors equipped, that means, if we have sensors equipped with tags. Then sensors sensing data will be through the tags. To the right of the figure we will see the antenna and reader. Basically, we can call it a “reader.” The reader will be transmit to the electromagnetic fields which is EM wave. Containing energies which is wireless signals through antennas to the tag. So this is electronic-magnetic fields based on electric and magnetic interactions. So the electric EM fields received by the RFID tag will be converted into electronic energy.
So based on this electronic energy, it makes the tags get energy to send the data out. So every time when the reader try to read the data of the tag, just emit signals. Once the tag receives the signals, then the data will be sent out. The energy will be basically provide by the reader. So that means the tag is basically no power. This is called the RFID. Basically this kind of operation is so-called the “passive RFID,” no power. If we have battery equipped with the RFID tag, they will be called “active.” The major difference between these two is the distance. So for RFID tag, passive, the distance between the tag and the reader can only be 1 to 3 centimeters.
But for active, it can be 10 meters to 30 meters or even longer. Okay, this is difference between RFIDs. Okay this is basic operation. Down below we have some examples. So you can see, we have basic examples and the passive readers we amplify the last one here is something like a circuitry. We see lots of copper loops. It represents antenna. A reader’s EM fields will be induced electricity powers, based on this antenna on the tag. Okay so the tag receives the EMF. The signal’s energy converts to electricity then get energy to trigger the circuit on the tag. The signal, the data, can then be transmitted. To the right is active one.
Okay we look at the system operations from the viewpoint of application. Okay so you see, we have basic, basic RFID systems which is tag and reader. On the right, lower bottom, of the figures. Here we see the readers gather data. It will send the data to the processing unit. Here we call it central computer. Then the data will be collected and through the network, maybe store in some secondary devices. So we see the RFID, the sensing, and we see the computing and also we see the big data or even in the cloud. This is the whole system of RFID. So we see the operation of RFID and we also look at the over..the whole picture of RFID applications.
Okay the next part we talk about the networking layer which is means how data can propagate it to the backend. Okay so we call it data propagation in IOT. This basically talk about the communication or networking technologies. Since once we have look at the technologies, in general we have lots of representation samples, so that’s why we have forensics says technologies equals to the standards. Basically we can apply the wired and wireless, two major category. Wired, so far, include ethernet and recommendation standard 232. Wireless will be covered a lot. Okay, so for general wireless network, people talk about the wireless it means wi-fi. Which means wireless, local area network or Wi-Fi direct, but we’ve seen Wi-Fi a lot.
And the next one is public cellular networks. This is basically, what we mean, the mobile communication is for long distance. Include the 3G, 4G and future, the 5G. And the last one is so called the short distance of like bluetooth, RFID, the example we just explained it and ZigBee, Z-wave and so forth. So you will see the three technologies
here: WIFI, mobile, and bluetooth will be underlined in the following three slides you will explain. We will make a brief summary of these three, to look at a bit detail about the difference between these three. Last one we talk about the industrial applications. So we have industrial wireless sensor network. What is “wireless sensor network”? Basically, we talk about networks means lots of devices connect together. Sensor networks is dedicated for sensors connected together. Wireless means the connection will be in wireless formats, no wired connected. Industrial means it’s dedicated designed for industrial applications, for factory. Okay, so this is so-called the wireless sensor network. We put the one “I” industrial wireless network, or industrial IOT. Okay, so this is some standards.
Basically, they are all wireless. Like IEEE 802.15.4., IEEE 802.15.4e, and so forth. We are not going to look at the detail about this one. Just mention, for IOT, we have two similar terms. One is the wireless sensor network. So in many case, when we talk about the wireless sensor network, it basically is the IOT already. Another one is so called the cyber physical system, CPAs. This is the basic technology applied for industrial 4.0. But there will be out of the range of this course, so we just mention about a little bit. So, keep in mind when we talk about the IOT, basically WSN and IOT will be the same in most cases.
Okay, look at the first one, the Wi-Fi technology, basically this is the short distance local area network. It means we have devices connected together within same building. Okay, or among buildings within a few kilometers. This is what we mean local area network. But these devices basically communicates to each other in a wireless through the antenna. This is so called the wireless local area network. People like to use the term “Wi-Fi” fidelity. Means wireless fidelity. This is what you mean wi-fi. We just look at the latest technique, technology or the standard. All of the wifi technologies will be standardized by IEEE, as you heard about it “I-E-E-E,” which is the abbreviation of Institute of Electrical and Electronics Engineer.
Okay that means WiFi standards are defined by the IEEE.
We look at three technologies: 11.n , 802, and 802 If you have an access-points equipped at your office, or at your house, you will see they are all 11N 11AC ready or even 11AD. The difference is the speed. Okay, so we will only look at the first two. One is how fast the data can be transmitted on the difference standards or technologies. So look at 11N, there will be 600 megabits per second. AC will be 3.2 gigabits and 11AD will be up to 7 gigabits. So 7 gigabits per second, in this rate we can propagate the high definition video without compressions in original forms through the wireless. This is very high speed.
The coverage will be basically less than 100 meter. Of course it depends on the strength of the emitting signals, the transmission power, which can be adjusted. And also it depends on the environment. Since once you will have a block, furniture, or walls, it will be blocked wireless signal a lot. So the coverage or the distance of the wireless signals is basically a references. 100 meters is basically theoretical values for your references. Okay, this is WiFi technology.

After sensors get signals, how does the electronic brain know?

In the Internet of Things, it is the wireless network which makes it happen. In this video, Prof. Ke will talk about several network technologies that are involved, such as RFID, WIFI, and Bluetooth.

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