Many friends don't know much about the two frequency bands of WiFi wireless signal. Today, wavelink will give you a detailed explanation.
Firstly, the history of wireless WiFi is reviewed
The first generation 802.11 was formulated in 1997, only running at 2.4GHz, with the fastest speed of 2Mbit / s
The second generation 802.11b, in 1999, only runs at 2.4GHz, with the fastest speed of 11mbit / S (also known as WiFi).
The third generation 802.11g/a, in 2002, runs at 2.4GHz and 5GHz respectively, with the fastest speed of 54mbit / s
The fourth generation 802.11n, in 2007, can run at 2.4GHz or 5GHz, from 150mbit / s, the fastest 300mbit / s, or even 450mbit / s
The fifth generation 802.11ac, in 2012, only runs at 5GHz and can provide at least 1Gbps bandwidth for multi station wireless LAN communication.
Difference between 2.4G and 5.8G wireless WiFi signal:
Wireless WiFi uses these two frequency bands, which are 2.4G and 5.8G, respectively. The same point is that they are assigned to wireless WiFi as frequency bands, and they belong to civil frequency bands, so there is no need to apply to the Commission for filing. The specific differences are as follows:
1. 2.4G frequency range: 2412-2472mhz, about 60MHz; 5.8G frequency range: 5725-5850mhz, about 125MHz
2. 2.4G band wireless WiFi signal is our usual sense of wireless WiFi, which can directly connect with our computer or mobile phone to access the Internet.
3. 5.8G is also a WiFi signal, but our computers and mobile phones generally use 2.4G WiFi, so 5.8G is marginalized.
4. The latest 802.11ac standard has only 5g band, mainly because the 2.4G band is too crowded.
5. The number of mobile phones supporting 5.8G wireless WiFi is gradually increasing, which is called dual band, because 2.4G support is necessary.
The difference between 2.4G and 5.8G signal transmission characteristics:
1. Compared with 2.4G, 5.8G signal is less interfered by the same frequency band, but its penetration is not as strong as 2.4G, and it is easy to be absorbed by metal or other obstacles.
2. 2.4G wireless WiFi has better diffraction ability than 5.8G. For example, if you install a WiFi device at home, you can receive your signal next door or a little farther away.
3. Because WiFi, microwave oven and Bluetooth are used in 2.4G band, many home wireless routers use this band, so 2.4G is easy to cause channel interference.
4. The 5.8G frequency band is relatively wide, and the corresponding equipment is relatively less, so the 5.8G frequency band is not easy to cause interference（ There will also be interference, but relatively less)
5. The transmission distance of 5.8G device is longer than that of 2.4G device, and the rain attenuation is smaller and the stability is better.
About the latest 802.11ac 5GHz wireless WiFi:
1. In 2014, Apple's iPhone 6 and other high-end flagship phones began to be equipped with 802.11ac WiFi module as standard
2. In 2016, 1000 yuan mobile phones began to be equipped with 802.11ac wireless WiFi module as standard
3. Wireless routers supporting 802.11ac Gigabit 5g are more expensive.
4. China's 5.725-5.825ghz: 4 channels, the mobile phones bought in Japan can't be used in China's 5g router (Japan's 5.15-5.25ghz: 4 channels)
5. 5g attenuation is too strong, there is no signal in every 1-2 walls, 2.4G can pass through about 3-5 walls.
6. 802.11ac Gigabit wireless WiFi has little meaning for Internet access, and home broadband is still at the level of 10m.
7. It supports 802.11ac Gigabit wireless WiFi, 2.4G and 5.8G at the same time