Hello, welcome to Cellular Communication class. I am Professor Daesik Hong at Yonesi University, Seoul, Korea. In this course, you will study how the cellular communication works. You must have a cell phone or a smart phone. What do you do with the cell phone? Voice call, SNS, email, games, video streaming? I'm sure that you are familiar with these words. These services are available with the help of the mobile communication technology. Then, how much do you know about the cellular communication system or technologies? Are you familiar with these words? Data rate, bandwidth, BER, RSRP, SINR? If you know more than half of these, I could say you are a specialist in the area of a mobile communications system. None of this? Don't worry about that. If you take our courses, then you will become familiar with this. These words are basic parameters in mobile communication systems. Actually, you can see these parameters easily in your own phone. Please pick up your phone. I'll tell you how we can see those parameters in your phone. This short video is an example of a Samsung device. Please type *#0011#, then you will see this screen. This information tells you communication parameters of your phone. If you have a Huawei or a Xiaomi device, try typing this code, *#*#7262626#*#*. Wow, long right? Or the bottom, the longer one. If you are using an Android phone in Korea, try this one. *123456#, then you will see the same information. If that doesn't work, you can try all of these two apps in your phone. Network Cell Info Lite And LTE discovery. Actually, you can download these applications from the Google Play easily. Then, you will also be able to see the same information. Finally, if you have an iPhone, type this code. Then, you will also be able to see this information. Okay, then let's talk about with this screen. Have you ever seen this information before? I think you haven't. UARFCN, bandwidths, band, cell ID. Actually, this screen shows the wireless communication information for your cell phone, as I already told you. Among them, I'll explain three basic parameters. The first one is bandwidth or BW. Your cell phone shows how much bandwidth you are using now. If you are using the LTE system, it may show 10 or 15 or 20 megahertz bandwidth. In the yellow box in the figure, you can see that the bandwidth is 20 megahertz. If the bandwidth of your phone is 20 MHz, you can send twice as much data as a 10 MHz bandwidth. That is if your phone shows a bigger number in the yellow box I mean the bandwidth, you are using wider bandwidth. And that means you can send more data. The second one is the frequency band indicator. Typically, the frequency band is fixed by the mobile network operator. In Korea, there are three operators, SKT, KT, and LGU+. And SKT telecom uses band 1, 3, and 5. If you are using band 1, that means your phone is using 2100 MHz frequency. I'm in Korea now, and I'm using SK Telecom, so my phone shows that I'm using band number 3. You can see this in the yellow box. That is my phone is using the 1800 MHz frequency. If you are in the United States and using Verizon, the band will be 2, 4, 13. So if you are using band 13, your phone is using 700 MHz frequency. The last one is the ID of a base station. Every base station has an address. In order to assign a different address to each base station, we are using two parameters, PLMN. That means Public Land Mobile Network, and the Physical Cell ID. PLMN presents the operator and the physical cell ID is the local base station ID. Let's go to the figure. Please see the Android case. In the first yellow box, the PLMN is 45005. This number is assigned to SKT in Korea. And the second box physical cell ID is 16378354. With these two information, we can recognize to which base station I'm now connected to. If I move one mile from here but still stay in Korea, then physical cell ID would be changed but the PLMN would not, because I'm still in Korea even though the base station is changed. Well, I have just explained these basic parameters for wireless communication in my cellphone. Do you understand what I explained? Bandwidth, frequency indicator, cell ID. I hope you say yes. The goal of this lecture series is to provide you with basic knowledge about mobile communication technology. After you have finished taking this series, come back and take another look at this. I'm sure that you will know many of the parameters in this slide. This is the outline of our lecture series. You're watching my course, the first one. In my course, as an introduction, you will get a brief history of mobile communication systems from 1G to 5G. Okay, now let's move on to the first generation mobile communication systems.