Okay, next one we like to see the so-called the long distance cellular networks. Basically, popular wireless network system. Basically it’s the cellular systems. So we first look at the idea of the cellular systems, then we look at the next slide. Okay, next slide is going to talk about cellular mobile communication for long distance propagations. Okay, so this is the cellular systems. We have mobile users. For example we have sensors that will be mobile users. Sometimes sensors will be equipped on the mobile devices. Or sensor it can move itself. The signal basically send to a base station. So in a cellular system the “base station” is the key components.
Base station play a role of transmit or receive signals between the mobile devices. We see the forward link means the data will be come from the base station. Reverse link means the data is out of the mobile devices. Sometimes we call the direction from the mobile devices to base station as “uplink.” And from mobile base station to the devices is called the “downlink.” So you can see the uplink / downlink, it play the same role, same meaning of forward and reverse. Okay, then the mobile base station will be through some switching that means the networking can connect to another mobile station. That’s why we can make a phone call from the caller to callee.
Okay, so for mobile devices communicates in a cellular systems, both ends has to connect to base stations. Then the base station will be set up connection path between the two base stations among networks. And also, if we talk about the application on the digitized packet switching, that means we can transmit the data. In short, the purpose, the figures here means we are making a voice call, but also we can transmit the data like we talk about the IOT. Sensing will be a data. The data will not be pronounced. The data have been transmitted in the digital form, 0101 format. Okay, so this signal will be in packet which is format of the data.
The data will be transmitted through a same systems through the internet and send to the backend system. Okay here, this is the basic idea, but the key things we have to know is what uplink, what is downlink, what is base station. Okay, so then we look at the cellular mobile communication systems. We have four generations. First generation, second generation, but they are all low speeds for data transmissions in terms of data rate. So we look at from the third generation, 3G, up to 4G so far. In between we have 3.5, 3.75 and 3.9 and 4G. Okay so last one, 4G, means the long term evolution LTE.
We’re not going to address the detail, so just put a very short summary as a comparison for the idea of showing the difference between these different generation technologies. So the key difference is the data rates. As you see, if we look at the downlink for 3G, it maybe 384 kbits per seconds, but for 4G it will be 1 gigabits per second. This K, kilobit means 1000 bit per seconds, which is not a big number, but gigabit means 10 to the 9, power of 9 bits per second. There will be a huge number. It will be a huge number. So you can see the difference between rates. This is only for your references.
You may google the internet to see more comparisons between different generation of technologies. But basically all of this will be standardized by the standard organization called the 3GPP, the 3rd Generation Partnership Project. Last one, we will look at short distance wireless communication. This is called the “bluetooth,” so I think this one you will see a lot. This is the basically, proposed by bluetooth forums for short distance. It can be equipped on devices to exchange data and also can provide some kind of applications for IOTs. So bluetooth basically, means, it transmits low power. That’s why we can only transmit for a short distance and..but low power imply low power consumption. It imply low cost.
So with a small battery we can operate longer. These are the versions for bluetooth. We have .01, .1, 1.2. In short, we say 1.X and 2.X, 3. , and 4.X. And last one, to be announced by 2017, which is bluetooth 5. So this is version from 1 to 5. Okay, again 1 and 2, with those speeds, we will know it. So we talk about, we will focus on the 3, 4, 5 different versions. Bluetooth 4.0 is the current measure standard technology for bluetooth application or bluetooth devices since bluetooth 4.0 represents low energy. Means it consumes a little bit of powers. It possess the capability of low power consumption, and power saving capability.
Okay so with a small batteries, it can use for very long time. This is bluetooth we call BLE 4.0. Okay, in terms of bluetooth, we look at again, how fast, how long, what will be the distance for the communication between by applying the bluetooth technology? And what will be the data rate when we transmit the data out. Data rate in terms of how many bits can be transmitted, the digital signal in bits per second. Okay so here we see, in most case, we talk about bluetooth. The data rate will be in 1 to 2 megabits per second and the distance will be confined into 10 meters around.
But from TIVO we have something like 25 mbits per seconds, 50 mbits per seconds. For the distance we have like 60 meters. It is for another standard. Basically for bluetooth technology, we have class 1, 2, 3, 4, four different classes. Class 1 is basically for industrial. 25 to 50 megabits per second is class 1 devices, for industrial application. 1 to 2 megabits is class 2 standard. Basically it is for commercial use. Okay this is the overview of bluetooth. Okay, so all you have to know is basically so far, it represents the low power, low cost, and short distance wireless transmission technology.
You see, okay, all we have exams, WIFI 3G, 4G, bluetooth, they are all operates in wireless, basically in IOT.