WLAN (WiFi-802. 11x) chgaiuedrbents 802.11k 802.11a 802.11e Radio roule 5 GHz 54 Mbps Quality of Service 10eabpamebbve MAC) 1999 2001 2003 2005 2007 802.11b 80211802i 2.4 GHz 盘GH把 ed Security 11 Mbps 54 MbpsWLAN (WiFi-802.11x) 802.11n 100 Mbps (above MAC) 802.11a 802.11b 802.11g 54 Mbps 5 GHz 11 Mbps 2.4 GHz 54 Mbps 2.4 GHz 802.11e Quality of Service 1999 2001 2003 2005 2007 802.11i Enhanced Security 802.11k Radio Resource Measurement ◼ Physical Layer Enhancements