802.16 is part of the 802 local and metropolitan area standards series of the IEEE. Other important network technologies in this series include the 802.3 fixed-line ‘Ethernet’ standard and the 802.11 WLAN standard. While the fixed-line and WLAN standards share concepts concerning how the network is managed and how packets are transferred between the devices, 802.16, as a metropolitan area network standard has taken a fundamentally different approach. There are important differences on layer 1 (physical layer, PHY) and layer 2 (data link layer, MAC) of 802.16 compared to 802.11 WLAN. The most important ones are the following:
- An 802.16 network can be operated in several modes. In the point-to-point mode, 802.16 is used to build a bridge between two locations. A second mode, the point-to-multipoint mode, is used to offer Internet access and telephony services to private customers and businesses. As this is the main application for the technology in the years to come, this chapter focuses mainly on this mode.
- In 802.16 point-to-multipoint mode, access to the network by client devices, also referred to as subscriber stations (SSs), is managed from a central authority. In 802.11 (WLAN) in comparison, clients can access the network whenever they detect that the air interface is not being used.
- SSs do not receive individual frames. In the downlink direction (network to SS), data is embedded in much larger frames. During transmission of the frame, the network can dynamically ...