Many people will find that the wireless Internet access of the computer used at home is WLAN, and the Internet access of mobile phones or tablets is also called WIFI. They are all the same wireless Internet access. How come there are two different names, so what do wlan and wifi mean? Where is the difference between wlan and wifi? Here we introduce the specific meaning of these two Internet access methods and the difference between wlan and wifi.
What is WLAN
wlan (Wireless Local Area Networks) means wireless local area network and is a data transmission system. It uses radio frequency (RF) technology for data transmission to achieve a smooth network without network cables and distance restrictions. WLAN uses ISM (Industrial, ScienTIfic, Medical) radio broadcast frequency band communication. The 802.11a standard of WLAN uses the 5 GHz frequency band and supports a maximum speed of 54 Mbps, while the 802.11b and 802.11g standards use the 2.4 GHz frequency band and supports speeds of up to 11 Mbps and 54 Mbps, respectively. At present, the protocol standards included in WLAN are: IEEE802.11b protocol, IEEE802.11a protocol, IEEE802.11g protocol, IEEE802.11E protocol, IEEE802.11i protocol, wireless application protocol (WAP). 
wlan technical requirements:
Since the wireless local area network needs to support high-speed, bursty data services, indoor use also needs to solve the problems of multipath fading and crosstalk between subnets. Specifically, the wireless LAN must meet the following technical requirements:
(1) Reliability: The system packet loss rate of the wireless LAN should be lower than 10-5, and the bit error rate should be lower than 10-8.
(2) Compatibility: For the wireless LAN used indoors, it should be compatible with the existing wired LAN in network operating system and network software as much as possible.
(3) Data rate: In order to meet the needs of LAN traffic, the data transmission rate of wireless LAN should be above 1Mbps.
(4) Communication secrecy: Since data is transmitted in the air through wireless media, wireless LAN must take effective measures at different levels to improve communication secrecy and data security performance.
(5) Mobility: support full mobile network or semi-mobile network.
(6) Energy-saving management: when no data is sent and received, the site machine is put into a sleep state, and activated when data is sent and received, so as to achieve the purpose of saving power consumption.
(7) Miniaturization and low price: This is the key to the popularization of wireless LAN.
(8) Electromagnetic environment: Wireless LAN should consider the influence of electromagnetic on human body and surrounding environment.
wlan hardware equipment (1) wireless network card. The function of the wireless network card is basically the same as that of the Ethernet network card. It serves as the interface of the wireless local area network and can realize the connection and communication between the clients of the wireless local area network.
(2) Wireless AP. AP is the abbreviation of Access Point, and wireless AP is the access point and wireless gateway of the wireless local area network. Its function is similar to the hub in the wired network.
(3) Wireless antenna. When the network devices in the wireless network are far apart, as the signal weakens, the transmission rate will drop significantly so that the normal communication of the wireless network cannot be achieved. In this case, it is necessary to enhance the received or sent signal by means of a wireless antenna
What is WIFI
WIFI (WirelessFidelity, wireless fidelity) technology is a brand of wireless network communication technology based on the IEEE 802.11 series of standards, the purpose is to improve the interoperability between wireless network products based on the IEEE 802.11 standard, by the Wi-Fi Alliance (Wi-Fi Alliance) holds, in simple terms WIFI is a wireless networking technology, used to connect computers through the network, but now is connected to the Internet through radio waves. The Wi-Fi Alliance (also known as: Wireless Local Area Network Standardization Organization WECA) was established in 1999. The name at that time was called Wireless Ethernet CompaTIbility Alliance (WECA). In October 2002, it was officially renamed Wi-Fi Alliance. 
Like Bluetooth technology, wifi belongs to the short-range wireless technology used in offices and homes. The technology uses a frequency band around 2.4GHz, which is currently an unlicensed wireless frequency band. There are currently two standards available, namely IEEE802.11a and IEEE802.11b. In the case of weak signals or interference, the bandwidth can be adjusted to 5.5Mbps, 2Mbps, and 1Mbps. The automatic adjustment of the bandwidth effectively guarantees the stability and reliability of the network. This technology is favored by manufacturers due to its own advantages.
Since the implementation of IEEE 802.11b, wireless networks have made great progress, so products based on this technology have gradually increased, and it is very necessary to solve the compatibility problems between products of various manufacturers. Because IEEE is not responsible for testing the compatibility of IEEE 802.11b wireless products, this work is undertaken by the non-profit organization spontaneously formed by manufacturers: the Wi-Fi Alliance. This alliance includes the major wireless LAN equipment manufacturers, such as Intel and Broadcom, as well as familiar Chinese manufacturers ASUS and BenQ. All products that pass the WiFi Alliance compatibility test are approved to be marked with "Wi-Fi CERTIFIED". Therefore, when we buy IEEE 802.11b wireless products, it is best to buy products with Wi-Fi marks to ensure compatibility between products
The official name of Wi-Fi (WirelessFidelity, wireless compatibility certification) is "IEEE802.11b", and like Bluetooth, it belongs to the short-range wireless technology used in offices and homes. Although the technology is worse than Bluetooth technology in terms of data security, it is slightly better in terms of radio coverage. Wi-Fi coverage can reach about 300 feet (about 90 meters), the office needless to say, it can also be used in a smaller building.
The difference between WLAN and WIFI
1. In fact, WIFI is a trademark of WLAN (Wireless Local Area Network Alliance). This trademark only guarantees that the products using this trademark can cooperate with each other. It has nothing to do with the standard itself, but because WIFI mainly uses the 802.11b protocol, people Gradually used to use WIFI to call 802.11b protocol. In terms of inclusion, WIFI is a standard of WLAN. WIFI is included in WLAN, which belongs to a new technology adopting WLAN protocol. The coverage of WiFi can reach about 300 feet (about 90 meters), and the maximum of WLAN (plus antenna) can reach 5KM.
2. WIFI (Wireless Fidelity), also known as 802.11b standard, its biggest advantage is its high transmission speed, which can reach 11Mbps, and its effective distance is also very long, and it is also compatible with various existing 802.11DSSS equipment. Wireless Internet has become a reality. The coverage of radio waves is wide. The coverage of radio waves based on Bluetooth technology is very small. The radius is only about 50 feet or about 15 meters, while the radius of Wi-Fi is about 300 feet or about 90 meters. Needless to say, the office It can be used even in the whole building. However, with the development of wifi technology, the future coverage of wifi signals will be wider.
Introduced here, I believe everyone should understand the difference between WIFI and WLAN. For most friends, we mainly know that WIFI and WLAN are all technologies that realize wireless Internet access, and WLAN wireless Internet access actually includes WIFI wireless Internet access, WLAN and WIFI The difference lies in the wider coverage of WLAN wireless Internet access, and WIFI wireless Internet access is more suitable for smart small digital products such as smart phones, tablet computers and so on.
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