Wireless LAN type

Wireless LAN type

 There are several standards for wireless LAN. Currently popular standards include IEEE802.11b, IEEE802.11g, IEEE802.11a, and IEEE802.11n.

 Depending on the standard, the radio frequency band to be used and the transfer speed are different. Some wireless LAN devices support multiple standards. Wireless LAN standards include IEEE802.11b, IEEE802.11g, IEEE802.11n (Wi-Fi4), IEEE802.11ac (Wi-Fi5), and IEEE802.11ax (Wi-Fi5). We will now briefly describe the characteristics of each standard.

IEEE802.11b

 The IEEE802.11b standard is compatible with the existing IEEE802.11 standard. The wireless frequency uses the 2.4 GHz band, and the transmission speed can be increased from 2 Mbps to a theoretical maximum of 11 Mbps. Data communication is possible in a wide range even in the house, and it can be used stably because there is little interference with other devices that use radio waves.

 Like IEEE802.11g, it can be used in public spaces (stations, public institutions, lodging facilities, cafes, etc.) with wireless LAN access points called free spots.

*The maximum transfer speed is a theoretical speed. Depending on the communication procedure, etc., the effective speed will be slower.

IEEE802.11g

 IEEE802.11g is an upward compatible method of IEEE802.11.b and can also support the IEEE802.11.b method. Therefore, if IEEE802.11.b is used to build a wireless LAN, IEEE802.11g can be used for smooth migration.

The radio frequency uses the same 2.4GHz band as IEEE802.11.b, and the theoretical maximum transmission speed is 54Mbps.

*The maximum transfer speed is a theoretical speed. Depending on the communication procedure, etc., the effective speed will be slower.

IEEE802.11a

 The IEEE802.11b standard was designed to be compatible with the existing IEEE802.11 standard, but this one was standardized using the latest technology at the time without being bound by compatibility.

 The radio frequency uses the 5GHz band, and the theoretical maximum transmission speed is 54Mbps. If you use it only in the room, the radio waves are easy to reach and you can use it stably, but if you are in different rooms or on different floors, the radio waves are difficult to reach and the exchange of data becomes unstable.

 The center frequency of the channel used for IEEE802.11a has become an international standard, replacing the 4-channel allocation of J52 (5.15 to 5.25 GHz) used in Japan due to the revision of the ministerial ordinance in May 2005. W52 has been changed to 4 channels, and W53 has added 4 channels.

This makes a total of 8 channels available.

 In January 2007, an amendment to the ministerial ordinance added 11 W56 channels that can be used outdoors, bringing the total number of channels available to 19.

This added channel is also available outdoors.

 Due to the change in channel allocation, even if you are using a product that supports 802.11a, there is a possibility that you will not be able to connect between devices manufactured at different times.

The appeal of IEEE802.11a is that it can be used outdoors and has a large number of available channels.

IEEE802.11n (Wi-Fi4)

Draft version 1.0 of this standard was established in March 2006, draft version 2.0 was formulated in August 2007, and was approved as an official standard in September 2009.

 It is a standard that allows data communication at a maximum transmission speed of 600 Mbps and an effective speed of 100 Mbps or more using the 2.4 GHz/5 GHz radio frequency band. Higher speed data communication is possible than the conventional method.

High-speed data communication is possible, so you can enjoy high-definition images such as digital high-definition broadcasting.

Wireless broadband routers typically support multiple wireless standards.

IEEE802.11ac (Wi-Fi5)

 IEEE802.11ac is a Wi-Fi standard that was officially established in January 2014, and is the fifth-generation standard that succeeds IEEE802.11n. IEEE802.11ac achieves a theoretical high-speed communication of 6.93 Gbps by extending the technology of IEEE802.11n.

 Expanding the IEEE802.11n communication technology, expanding the frequency band (40MHz → 80MHz), using multi-level modulation (64QAM → 256QAM), and using frame aggregation to increase the data frame size by 16 times. It is ready to handle.

Compared to IEEE802.11n (theoretical speed 600Mbps), it achieves high-speed communication about 11.5 times faster.

 Looking at the figure of 6.93 Gbps, you may think that it has become extremely fast, but it is only theoretical and the communication speed varies depending on the product. You may have seen home broadband routers with a maximum speed of 1300Mbps.

IEEE802.11ax (Wi-Fi6)

 IEEE802.11ax is the next-generation Wi-Fi standard following IEEE802.11ac (2014), and is also called Wi-Fi6. The maximum communication speed (theoretical value) is 9.6 Gbps, about 1.4 times faster than IEEE802.11ac (Wi-Fi5).

 Compared to IEEE802.11ac, it may seem that the communication speed has not improved so much, but with the previous standard, when many child devices are connected at the same time, the communication speed drops drastically There was a drawback that it could not be done.

 Therefore, IEEE802.11ax is devised so that communication performance does not deteriorate even when many slave devices are connected and communicate at the same time.

 IEEE802.11ac could only use the 5GHz band, but 802.11ax can use both the 5GHz band and the 2.4GHz band. *It is possible to combine with 2.4GHz of IEEE802.11n.