What Is WiFi?
WiFi, also known as Wi-Fi, is a trademark owned by the Wi-Fi Alliance (WFA). It is a WLAN technology based on the IEEE 802.11 family of standards. Since the release of the first-generation IEEE 802.11 standard in 1997, it has been evolved to the latest 6th-generation 802.11ax standard (Wi-Fi 6). Before the release of Wi-Fi 6, Wi-Fi standards were identified by versions from 802.11b to 802.11ac. Later, the WFA decided to make the Wi-Fi standards easier to understand and remember for Wi-Fi users and device vendors, and therefore renamed the standards using generational numbering.
What Does Wi-Fi Stand For?
When it comes to Wi-Fi, there are two major organizations you may have already heard of: IEEE and WFA.
The IEEE established the 802.11 Working Group to develop WLAN standards in 1990, and released the first 802.11 standard (802.11-1997) for WLAN in 1997. Since then, the IEEE releases a new standard every four to five years, the latest being the 6th-generation 802.11ax standard.
802.11 standard evolution
- Standard origin: 802.11-1997 defeats other standards and is first used as the WLAN standard in the industry.
- Standard enhancement: 802.11b makes the large-scale commercial use of WLAN possible by delivering a rate of 11 Mbit/s. 802.11a further increases the rate to 54 Mbit/s by first introducing orthogonal frequency division multiplexing (OFDM) technology to the 802.11 standard on the 5 GHz frequency band.
- Standard extension and compatibility: 802.11g extends the use of OFDM technology to the 2.4 GHz frequency band and is backward compatible with 802.11b.
- High throughput (HT) standard based on MIMO-OFDM: 802.11n supports single-user MIMO (SU-MIMO) and OFDM, and delivers a rate of 600 Mbit/s.
- Very high throughput (VHT) standard: 802.11ac supports downlink multi-user MIMO (DL MU-MIMO), provides channel bandwidth of up to 160 MHz, and delivers a rate of 6933.33 Mbit/s.
- High efficiency WLAN (HEW) standard: 802.11ax introduces technologies such as orthogonal frequency division multiple access (OFDMA), uplink MU-MIMO (UL MU-MIMO), basic service set (BSS) coloring, and target wake time (TWT), further improving the throughput in high-density scenarios and increasing the rate to up to 9607.8 Mbit/s.
The WFA is a commercial organization that promotes and markets IEEE 802.11 standards as well as certifies the interoperability of 802.11 products worldwide. The WFA was originally founded to promote the formulation of the IEEE 802.11b standard. In 2000, the WFA announced its official name and adopted the term "Wi-Fi" as its trademark.
What does Wi-Fi mean? Currently, there are two arguments. One is that Wi-Fi stands for Wireless Fidelity, which is similar to High Fidelity (Hi-Fi) — a category of audio equipment. The other is that Wi-Fi has no specific meaning or full name. No organization has officially stated that Wi-Fi stands for Wireless Fidelity. Additionally, the name Wi-Fi is often written as WiFi or wifi, but these are not approved by the WFA.
Wi-Fi vs. 802.11
The IEEE has developed and released 802.11 standards, but it does not test equipment for compliance with the standards. IEEE 802.11 standards are theoretical. Upon productization, 802.11 products provided by different manufacturers may be diversified. In such case, the WFA addresses the production and device compatibility issues of these products. The WFA certifies 802.11 products under the Wi-Fi CERTIFIED logo. Manufacturers of 802.11 products may use the Wi-Fi trademark owned by the WFA to brand their certified products.
Wi-Fi and IEEE 802.11 are so closely related that the two systems are often mixed up. Generally speaking, IEEE 802.11 is a WLAN standard, while Wi-Fi is a product implementation of IEEE 802.11. Besides Wi-Fi, there are other IEEE 802.11 standard implementations, such as WiGig. Wi-Fi is one of the best developed implementations.
Wi-Fi vs. WLAN
Wi-Fi is a trademark of the WFA, and is also a wireless network communication technology based on IEEE 802.11. The WFA has announced the use of Wi-Fi to improve the interoperability of products in compliance with IEEE 802.11 standards.
WLAN is short for wireless local area network. Quite simply, WLANs provide network communication using radio waves such as lasers and infrared signals, instead of physical connections. They provide wireless network communication using high-frequency radio waves (such as those on the 2.4 GHz and 5 GHz frequency bands) and comply with IEEE 802.11 standards. WLAN in our daily life refers to that implemented based on IEEE 802.11 standards. During the evolution and development of WLAN, various technical standards have emerged, such as Bluetooth, Wi-Fi, and HyperLAN2. Among them, Wi-Fi is now most commonly used due to its advantages such as simple implementation, reliable communication, high flexibility, and low implementation costs. Gradually, Wi-Fi becomes a synonym of WLAN.
Simply put, WLAN is a network system, while Wi-Fi is a technology in this network system. Therefore, WLAN includes Wi-Fi.
How to Deploy a Wi-Fi Network
A Wi-Fi network generally consists of at least one AP and one or more STAs. The AP allows STAs to connect to the Wi-Fi network. This function is also supported by other Wi-Fi devices such as wireless routers (integrated with the AP function).
In home scenarios, home wireless routers are most commonly used to achieve Wi-Fi connections. In enterprise scenarios, Wi-Fi connections can be set up in the following modes:
- Independent Fat AP deployment
A Fat AP can provide Wi-Fi coverage independently without the need of an additional management and control device. However, because the Fat AP controls STA access independently, STAs cannot roam between Fat APs. The STAs can use the Wi-Fi network only within the coverage area of the connected Fat AP.
Therefore, Fat APs are typically deployed to provide small-scale Wi-Fi coverage in home or SOHO environments. In enterprise scenarios, the "AC + Fit AP" and "cloud management platform + cloud AP" networking modes are typically used.
- Centralized AC + Fit AP deployment
The AC + Fit AP architecture is widely used for Wi-Fi network deployment in large and midsize campuses, such as shopping malls, supermarkets, hotels, and enterprise offices. The AC manages and controls all Fit APs connected to it through CAPWAP tunnels. The AC delivers configurations to Fit APs in batches, eliminating the need to configure APs one by one. This greatly reduces WLAN management and maintenance costs. Additionally, STAs can roam between Fit APs because their access authentication is centrally managed by the AC.
In small-scale Wi-Fi coverage scenarios, only a few APs are required. If an additional AC is deployed, the WLAN cost is increased. In such a scenario, Fat APs are recommended if STA roaming is not required. If STA roaming is required, cloud APs are recommended.
- Cloud-based deployment
Cloud APs provide similar functions as Fat APs, and can be deployed to build small WLANs in home or SOHO environments. Similar to the AC + Fit AP architecture, the cloud management platform + cloud AP architecture allows cloud APs to be centrally managed and controlled by the cloud management platform. Therefore, this architecture is also applicable to large and midsize networks.
Cloud APs are plug-and-play and are easy to deploy. They can be flexibly expanded out of space restrictions. Therefore, cloud APs are widely used in multi-branch scenarios.
- Author： Han Jian
- Updated on： 2021-09-02
- Views： 1099
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