Basis for Pure ALOHA Slotted ALOHA Comparison Introduced by Norman Abramson and his Introduced associates at the University of Hawaii in Introduced by Roberts in 1972. 1970. The user can transmit the data frame Frame The user has to wait till the next time whenever the station has the data to be Transmission slot start, to transmit the data frame. transmitted. In Slotted ALOHA the time is Time In Pure ALOHA the time is continuous. discrete. The probability of successful transmission The probability of successful Successful of the data frame is: transmission of the data frame is: Transmission S= G* e^-2G S= G*e^-G The time here is globally Synchronization The time is not globally synchronized. synchronized. The maximum throughput occurs at G = The maximum throughput occurs at G Throughput 1/2 which is 18%. = 1 which is 37%.

Name Description Note IEEE 802.1 Higher Layer LAN Protocols (Bridging) active IEEE 802.2 LLC disbanded IEEE 802.3 active IEEE 802.4 Token bus disbanded IEEE 802.5 MAC layer disbanded IEEE 802.6 MANs (DQDB) disbanded IEEE 802.7 Broadband LAN using Coaxial Cable disbanded IEEE 802.8 Fiber Optic TAG disbanded IEEE 802.9 Integrated Services LAN (ISLAN or isoEthernet) disbanded IEEE 802.10 Interoperable LAN Security disbanded Wireless LAN (WLAN) & Mesh (Wi-Fi IEEE 802.11 active certification) IEEE 802.12 100BaseVG disbanded Reserved for IEEE 802.13 Unused[2] development[3] IEEE 802.14 Cable modems disbanded IEEE 802.15 Wireless PAN active IEEE certification active 802.15.1 IEEE IEEE 802.15 and IEEE 802.11 coexistence Hibernating [4] 802.15.2 IEEE High-Rate wireless PAN (e.g., UWB, etc.) 802.15.3 IEEE Low-Rate wireless PAN (e.g., ZigBee, active 802.15.4 WirelessHART, MiWi, etc.) IEEE Mesh networking for WPAN 802.15.5 IEEE Body area network active 802.15.6 IEEE Visible light communications 802.15.7 IEEE 802.16 Broadband Wireless Access (WiMAX certification) hibernating IEEE Local Multipoint Distribution Service 802.16.1 IEEE Coexistence wireless access 802.16.2 IEEE 802.17 hibernating IEEE 802.18 Radio Regulatory TAG IEEE 802.19 Coexistence TAG IEEE 802.20 Mobile Broadband Wireless Access hibernating IEEE 802.21 Media Independent Handoff IEEE 802.22 Wireless Regional Area Network IEEE 802.23 Emergency Services Working Group IEEE 802.24 Smart Grid TAG New (November, 2012) IEEE 802.25 Omni-Range Area Network