Wi-Fi
Wi-Fi (which stands for “Wireless Fidelity”, sometimes incorrectly abbreviated WiFi) is the name of the certification granted by the Wi-Fi Alliance, formerly WECA (Wireless Ethernet Compatibility Alliance), a group that guarantees compatibility between devices that use the 802.11 standard
The IEEE 802.11 specification (ISO/IEC 8802-11) is an international standard that defines the characteristics of a WLAN
Due to improper use of the terms (and for marketing reasons) the name of the standard is confused with the name of the certification
A Wi-Fi network is actually a network that complies with the 802.11 standard
To devices certified by the Wi-Fi Alliance they are allowed to use this logo:
With Wi-Fi you can create high-speed wireless local area networks as long as the equipment to be connected is not too far from the access point
In practice, Wi-Fi supports laptops, desktops, personal digital assistants (PDAs), or any other type of high-speed device with high-speed connection properties (11 Mbps or faster) within a radius of several dozens of meters indoors (20 to 50 meters generally) or within a radius of hundreds of meters outdoors
Wi-Fi providers are beginning to cover areas with a high concentration of users (such as train stations, airports, and hotels) with wireless networks. These areas are called “local coverage zones”
The 802.11 standard sets the lower levels of the OSI model for wireless connections that use electromagnetic waves, for example:
- The physical layer (sometimes abbreviated "PHY" layer) offers three types of information encoding
- The data binding layer consisting of two sublayers: Logical Binding Control (LLC) and Media Access Control (MAC)
The physical layer defines the modulation of radio waves and signaling characteristics for data transmission while the data link layer defines the interface between the computer bus and the physical layer, in particular an access method similar to that used in the Ethernet standard, and the rules for communication between network stations. Actually, the 802.11 standard has three physical layers that set alternative transmission modes:
| Data Binding Layer (MAC) | 802.2 | ||
| 802.11 | |||
| Physical cover (PHY) | DSSS | FHSS | Infrared |
Any higher level protocol can be used on a Wi-Fi wireless network in the same way it can be used on an Ethernet network
Wifi standards
The original 802.11 standard, which allows 1 to 2 Mbps bandwidth, has been modified to optimize bandwidth (including 802.11a, 802.11b, and 802.11g standards, called 802.11 physical standards) or to specify components better to ensure greater security or compatibility. The table below shows the various modifications to the 802.11 standard and its meanings:
| Name of the standard | Name | Description |
| 802.11-1997 | 802.11 | The 802.11-1997 standard is the original version of the 802.11 standard, specifying two "theoretical" transmission rates of 1 and 2 Mbps that are transmitted over infrared (IR) signals. It also defines the carrier sense multiple access with collision avoidance (CSMA/CA) protocol as an access method. Many of his weaknesses were corrected in the 802.11b standard |
| 802.11a | Wi-fi 5 | The 802.11a standard (called Wi-Fi 5) supports higher bandwidth (the maximum total throughput is 54 Mbps although in practice it is 30 Mbps). The 802.11a standard provides eight radio channels in the 5 GHz frequency band |
| 802.11b | Wi-fi 1 | The 802.11 standard offers a maximum total throughput of 11 Mbps (6 Mbps in practice) and has a range of up to 300 meters in an open space. Uses the 2.4 GHz frequency range with three radio channels available |
| 802.11c | Combination of 802.11 and 802.1d | The combined standard 802.11c offers no interest to the general public. It is only a modified version of the 802.1d standard that allows you to combine the 802.1d with 802.11 compatible devices (at the data binding level) |
| 802.11d | Internationalization | The 802.11d standard is a complement to the 802.11 standard that is intended to allow international use of local 802.11 networks. Allows different devices to exchange information in frequency ranges based on what is allowed in the device's home country |
| 802.11e | Improvement of the quality of the service | The 802.11e standard is intended to improve quality of service at the data binding layer level. The goal of the standard is to define the requirements of different packets in terms of bandwidth and transmission delay to allow better audio and video transmissions |
| 802.11f | Roaming | 802.11f is a recommendation for access point vendors that makes products more compatible. It uses the IAPP protocol that allows a roaming user to clearly switch from one access point to another while on the move regardless of the branding of access points used in the network infrastructure. This property is also known simply as roaming |
| 802.11g | The 802.11g standard offers high bandwidth (with a maximum total throughput of 54 Mbps but 30 Mbps in practice) in the 2.4 GHz frequency range. The 802.11g standard is compatible with the above standard, the 802.11b, which means that devices that support the 802.11g standard can also work with the 802.11b | |
| 802.11h | The 802.11h standard aims to combine the 802.11 standard with the European standard (HyperLAN 2; 802.11h h) and comply with European regulations related to frequency use and energy performance | |
| 802.11i | The 802.11i standard is intended to improve security in data transfer (by managing and distributing keys, and by implementing encryption and authentication). This standard is based on the AES (Advanced Encryption Standard) and can encrypt transmissions running on 802.11a, 802.11b and 802.11g technologies | |
| 802.11Ir | The 802.11Ir standard was developed so that you can use infrared signals. This standard has become technologically obsolete | |
| 802.11j | The 802.11 standard j it is for the regulation of japanese what the 802.11 h is to european regulation | |
| 802.11k | The 802.11k standard allows wireless switches and access points to calculate and assess the radio frequency resources of clients in a WLAN network, improving their management. It is designed to be implemented by software, simply updating computers, as long as both clients (adapters and WLAN cards) and infrastructure (access points and WLAN switches) are supported | |
| 802.11n | Wi-Fi 4 | The 802.11n standard (called Wi-Fi 4) was a proposed modification to the 802.11-2007 standard to significantly improve network performance beyond previous standards, such as 802.11b and 802.11g, with a significant increase in speed. maximum transmission rate of 54 Mbps to a maximum of 600 Mbps. Currently the physical layer supports a speed of 300 Mbps, using two streams on a 40 MHz channel. Depending on the environment, the user could obtain a throughput of 100 Mbps |
| 802.11p | The 802.11p standard operates on the 5.90 GHz and 6.20 GHz frequency spectrum, designed with the idea of using it for communication between vehicles and with on-road infrastructure. It is the basis of dedicated short-range communications (DSRC). It also adds wireless access in vehicle environments (WAVE). This improvement is widely used in the implementation of Intelligent Transport Systems (SIT) | |
| 802.11r | Fast Basic Service Set Transition | The 802.11r standard (called Fast Basic Service Set Transition) allows you to set security protocols that identify a device on the new access point before it leaves the current one and passes to it. This feature, which once enunciated seems obvious and indispensable in a wireless data system, allows the transition between nodes to take less than 50 milliseconds. This time lapse is short enough to maintain communication via VoIP without noticeable outages |
| 802.11v | The 802.11v standard is used to allow remote configuration of client devices by allowing centralized (cellular network-like) or distributed station management through a data link layer (Layer 2) mechanism. This includes, for example, the network's ability to monitor, configure, and upgrade client stations. It also provides us with:
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| 802.11w | The 802.11w standard is based on the 802.11i protocol and serves to protect WLAN networks against subtle attacks on WLAN frames. Not finished yet. TGw is working on improving the IEEE 802.11 media access control layer to increase the security of authentication and encoding protocols. Attempts are made to extend the protection provided by the 802.11i standard beyond data to management frames, responsible for the main operations of a network. These extensions will have interactions with IEEE 802.11r and IEEE 802.11u | |
| 802.11ac | Gigabit Wi-Fi | The 802.11ac standard (called Gigabit Wi-Fi or Wi-Fi 5) was a modification of the 802.11n standard that consisted of improving transfer rates up to 433 Mbps, theoretically achieving rates of 1.3 Gbitps using 3 antennas. It operates within the 5 GHz band, expanding the bandwidth up to 160 MHz (in 802.11n networks it was 40 MHz), uses up to 8 MIMO streams and includes high-density modulation (256 QAM) |
| 802.11ax | Wi-Fi 6 | The 802.11ax standard (called Wi-Fi 6 or Wi-Fi 6th Generation by the Wi-Fi Alliance) is designed to operate in the existing 2.4 GHz and 5 GHz spectrums. It introduces OFDMA to improve overall spectral efficiency |
| 802.11be | Wi-fi 7 | The 802.11be standard (called Wi-Fi 7 or Extremely High Throughput (EHT) by the IEEE). It operates in all three bands (2.4 GHz, 5 GHz and 6 GHz) to fully utilize spectrum resources. While Wi-Fi 6 was created in response to the growing number of devices in the world, the goal of Wi-Fi 7 is to deliver amazing speeds to every device with greater efficiency. Wi-Fi 7 features 320 MHz ultra-wide bandwidth, 4096-QAM, Multi-RU and Multi-Link operation to provide speeds 4.8 times faster than Wi-Fi 6 and 13 times faster than Wi-Fi 5 |
It is also important to mention the existence of a standard called "802.11b+". This is a patented standard that contains improvements over data flow. On the other hand, this standard has some interoperability gaps because it is not an IEEE standard
Range and data flow
The 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.11ax, 802.11be standards, called “physical standards”, are modifications of the 802.11 standard and operate in different modes, which allows them to achieve different transfer speeds of data according to their ranges
| Date | IEEE Standard | Vel. max data | Bands | Channel size | Modulation | Antennas |
| 1997 | 802.11b (WI-FI 1) | 1 o 2 Mbps | 2.4 GHz | 20 MHz | ||
| 1999 | 802.11a (WI-FI 2) | 54 Mbps | 5 GHz | 20 MHz | 2003 | 802.11g (WI-FI 3) | 54 Mbps | 2.4 GHz | 20 MHz | 2009 | 802.11n (WI-FI 4) | 600 Mbps | 2.4 y 5 GHz | 20, 40 MHz | 2013 | IEEE 802.11ac (WI-FI 5) | 3.5 Gbps | 2.4 y 5 GHz | 20, 40, 80, 80+80, 160 MHz | OFDM 256-QAM | 4×4 MIMO DL MIMO | 2019 | 802.11ax (WI-FI 6) | 9.6 Gbps | 2.4 y 5 GHz | 20, 40, 80, 80+80, 160 MHz | 1024-QAM OFDMA | 8×8 UL/DL MU-MIMO | 2021 | 802.11ax (WI-FI 6E) | 9.6 Gbps | 2.4, 5 y 6 GHz | 20, 40, 80, 80+80, 160 MHz | 1024-QAM OFDMA | 8×8 UL/DL MU-MIMO | 2024 (possibly) | 802.11be (WI-FI 7) | 46 Gbps | 2.4, 5 y 6 GHz | Up to 320MHz | 4096-QAM OFDMA (with extensions) |
16×16 UL/DL MU-MIMO |