Wifi is nowadays present everywhere. Whether in our smartphones, tablets, connected watches or TVs, wifi is everywhere. Moreover, even on microwaves and refrigerators, it is now available.
Thus, almost all of our electronic devices have a wifi module, although they are not all the same. Yes indeed since its advent, wifi has undergone many changes and therefore several standards have been used.
We will see here a set of the different solutions offered by the manufacturers of wifi modules on our smartphones as well as for our other devices.
Today, the wireless transmission technologies used range from Bluetooth to communication satellites, including 4G and soon 5G. In the local area network sector, wifi technology is essential.
The different variants of wifi are grouped together in the 802.11 standard. This standard defines the part of the radio frequency bands (UHF and SHF bands) used by wifi to limit interference with other equipment.
For this reason, a number of wifi channels are therefore defined by States and standardization bodies. Although not strictly similar throughout the world, the frequencies of the ISM bands (2.4 GHz and 5 GHz) authorized for wifi in the different countries are nevertheless quite homogeneous.
The current wifi (802.11 standard) covers many different standards, all of which are prefixed by 802.11. Then a suffix in the form of a letter that allows these standards to be distinguished from each other. Overall, we are talking about seven different generations (802.11a/b/g/n/ac/ad/ad/ax). Each of which represents a significant change from the previous one. This time we will take a closer look at their specificities!
General Standards 802.11.
Dating back to the late 1980s, the first wifi standard has constantly evolved to incorporate technical advances. But also the constantly improving performance.
The table below lists the main features of wifi in the different standards contained in 802.11.
||Max theoretical throughput
|20 ou 40 MHz
||5 300 Mbps
||20, 40, 80 or 160 MHz
||6 757 Mbps
|| very low
||2 160 MHz
||2,4 & 5GHz
||10 530 Mbps
||20, 40, 80 or 160 MHz
From the table above, we can see that there are a multitude of Standards, all with specific theoretical flows. These rates can be maximised if the number of antennas is affected.
Note: MIMO (Multiple-Input Multiple-Output) is the multiplexing technique using several antennas to improve the S/N ratio and throughput. Each antenna is responsible for a flow. For example, the 802.11ac standard allows to manage up to 8 flows of 866 Mb/s for a theoretical d´bit of 6.7Gb/s.
The different 802.11n wifi Standards.
The 802.11n wifi standards.
IEEE 802.11n is a major revision that literally increases the theoretical maximum flow rate tenfold. The standard brings two evolutions to this end: MIMO technology and a doubled bandwidth.
The 802.11ac wifi standards.
IEEE 802.11nac is the IEEE 802.11 standard published in January 20144; it allows a higher bandwidth in the 5 GHz band.
The IEEE 802.11g standards.
The 802.11g wifi standards, published in June 2003, specifies a wireless data transmission mode at data rates up to 54 Mbit/s in the 2.4 GHz frequency band.
IEEE 802.11b allows point-to-multipoint transmission in line of sight over a distance of up to 300 meters with signal quality-dependent data rates of 1, 2, 5.5 or 11 Mbit/s.
The IEEE 802.11n standards.
The 802.11n wifi standards, ratified in September 2009, allows a theoretical bandwidth of up to 450 Mbit/s (in MIMO 3×3 : 3 antennas) in each of the usable frequency bands (2.4 GHz and 5 GHz). It improves on previous standards
The IEEE 802.11ac standards.
The 802.11ac wifi standards, which is a wireless transmission standard of the wifi family, standardized by the IEEE on January 8, 2014, allows high-speed wireless connection to a local network and uses exclusively a frequency band between 5 and 6 GHz2, with variations according to countries3.
The IEEE 802.11ad standards.
The 802.11ad wifi standards, also called WiGig, is a wifi standard that uses the 60 GHz frequency band. Its transmission power should be 16 times lower than that of 802.11ac wifi, for a range not exceeding 10 meters, but for a data rate of up to 4.6 Gbit/s on a single carrier1.
The 802.11ah standards.
The 802.11ah wifi standards is better penetration through obstacles (walls and partitions) and energy savings compared to conventional wifi standards operating in the 2.4 GHz and 5 GHz bands.
This item thus comes to an end and is by no means exhaustive because many aspects have not been addressed. The simple objective was to present the basics and main standards of wifi.
Wireless transmission has become an obvious part of our daily lives, but it is still an extremely sophisticated technology. The security of WiFi networks is controversial. I would like to remind you that it is quite possible to create a secure wifi architecture.