Hello
Today, under the name of Wifi, there are dozens of different standards that all share the same prefix: 802.11. You can find the most important information in the table below.
If most share some common points, each also represents a significant evolution compared to its previous one.
802.11b WiFi
We should rather say Wifi 802.11a and 802.11b. We are in 1999, the first WiFi networks arrive, the first standard is intended for companies, the second for individuals. However, they have a first real difference. The first uses the 5 GHz band and has an ODFM modulation that allows it to reach 54 Mb / s. The second operates on the 2.4 GHz band but its ODSS modulation caps it at 11 Mb / s.
802.11g wifi
In 2003, we witness the first change. The two previous standards are united under a single standard: 802.11g. It's a mix of the two. We recover the ODFM modulation from the private sector by associating it with the 2.4 GHz frequency. The objective is to combine power (in 54 Mb / s and range for all users. On the positive side, backward compatibility is ensured with the two old standards.
802.11n wifi
With Wifi n, we see the emergence of MIMO which stands for Multiple Input Multiple Output. As its name suggests, this technology allows Wi-Fi to operate multiple streams simultaneously. We speak for example of MIMO 2 × 2 for two antennas in transmission and two in reception, which doubles the speed compared to a configuration without MIMO, that is to say 300 Mb / s with 40 MHz. Wifi N can achieve 4 × 4 MIMO, an absolute maximum of 600 Mb / s.
802.11ac WiFi
The first wave, or first generation of the standard, offered a maximum throughput of 3.47Gbps, while the second wave offers a maximum throughput of 6.93Gbps. In addition to a strong increase in speed, the main novelty brought by this second wave is the appearance of MU-MIMO (Multiple-user multiple input / multiple output) technology.
This allows Wifi to use multiple streams simultaneously. With 802.11ac WiFi, these can be up to 8 simultaneously. This standard only works on the 5 GHz frequency, the waves are oriented thanks to beamforming and "Multi-User" allows the same terminal to manage several users at the same time.
802.11ad WiFi
The new 802.11ad standard offers a radically different approach to WiFi. This standard sacrifices range for extreme speed. It is based on the 60 GHz frequency band, which allows it to reach an impressive speed of 7Gbps. On the other hand, its range is very short and the connection cannot pass through walls and other obstacles.
Good choice for your deployment
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