WLAN
Introduction
WLAN is the local area network without using any wire or transmission cables in connection. It uses radio waves as the transmission media to transmit data under hundred meters. With the broadband technology installed in backend, multiple users are able to access the internet through wireless access points.
WLAN technology is widely used in many areas such as commercial site, universities, and public areas. It stands on IEEE 802.11 standards to follow the specification defined by Wi-Fi alliance. Wi-Fi alliance established in 1999, there are many Wi-Fi certified products already deployed in the market such as PC, NB, Game device, Video player, Smart phone, Printer…etc.
Standard
- 802.11,1997,2Mbps @2.4GHz
- 802.11a,1999,54Mbps @5GHz
- 802.11b,1999,11Mbps @2.4GHz
- 802.11g,54Mbps @2.4GHz
- 802.11n,MIMO and 40Mbit channel width technology(HT40)
- 802.11ac,1×1 MIMO,433Mbps @5GHz,80Mbit channel width。
- 802.11ad,Very High Throughput @60 GHz, WiGig.
- 802.11ax,based on 802.11ac, target for 4x times transmission rate
Application
WLAN is mainly defined for LAN replacement, internet connection, data or even voice transmission,802.11g/802.11a supported both 2.4GHz and 5GHz dual band to provide maximum 54Mbps data rates, 5 times higher rate compare to 802.11b continuously improve the quality of data/voice transmission. The new generation used MIMO technology even twice the transmission rate up to 108Mbps.
IEEE802.11n used multiple MIMO technology to improve the problems of flow decreasing in the network from 11a and 11g in order to achieve higher data rate (600Mbps) and longer transmission distance.
IEEE802.11ac success from 11n with more RF bandwidth, more MIMO spatial streams, it supports multiple users in downstream and higher density modulation (256QAM).
IEEE802.11ax is backward compatible to previous standard, target to pull up the average data rate in high density population area, with both MU-MIMO and OFDMA technology; it improves the distortion issue among multiple transmission path environments and brings even lower power consumptions than previous products.
Architecture