IEEE802.11n (Wi-Fi4)

IEEE802.11n (Wi-Fi4)

IEEE802.11n is a wireless LAN standard that remained in draft for a long time but was officially approved in September 2009.

　IEEE802.11n was in production even while it was still a draft, and IEEE802.11n itself was familiar even before it was officially approved. However, when it first went on sale, due to restrictions imposed by the Radio Law in Japan, it was only possible to use a bandwidth of 20MHz and only one channel.

　However, in June 2007, part of the Radio Law was amended, and the bandwidth that can be used simultaneously in wireless communication was raised from 20MHz to 40MHz, enabling channel bonding and increasing the theoretical maximum transmission speed to 300Mbps. I was.

　IEEE802.11n uses a frequency band of 2.4GHz/5GHz and achieves a maximum transfer speed of 300Mbps. As a standard, it achieves a maximum transmission speed of 600Mbps (40MHz channel bonding, when using 4 streams).

　With the ability to achieve communication speeds that greatly exceed those of the conventional IEEE802.11a/g, and the cost of compatible devices being reduced, it is now widely used and becoming the mainstream.

　Since IEEE802.11n can be interconnected with IEEE 802.11a, IEEE 802.11b, and IEEE 802.11g, it can be used in a mixed environment with conventional wireless devices, which is another factor in its spread.

　Compared to IEEE 802.11a and IEEE 802.11g, the transfer speed is dramatically improved by about 5 times, but this is achieved by a technology called channel bonding and a technology called MIMO (Multiple Input Multiple Output). doing.

IEEE802.11n (channel bonding)

　IEEE802.11n has dramatically improved transfer speed compared to IEEE 802.11a and IEEE 802.11g. This achieves high speed with a technology called channel bonding and a technology called MIMO (Multiple Input Multiple Output).