IEEE 802.16 is designed to support the following services:

• Digital audio/video multicast: Transports one-way digital audio/video streams to subscribers. The principal example of this service is a broadcast radio and video similar to digital broadcast cable TV and digital satellite TV. A special case of this service is two-way video such as in teleconferencing. In this latter case, delay requirements are stringent because of the interactivity involved.

• Digital telephony: Supports multiplexed digital telephony streams. This service is a classic WLL service that provides a replacement for wired access to the public telephone network.

• ATM: Provides a communications link that supports the transfer of ATM cells as part of an overall ATM network. The 802.16 link must support the various QoS services defined for ATM.

  Internet protocol: Supports the transfer of IP datagrams. The 802.16 link must provide efficient timely service. In addition, a variety of QoS services are now defined for IP-based networks, and 802.16 should support these.

• Bridged LAN: Similar to the IP-based support. A bridge LAN service enables transfer of data between two LANs with switching at the MAC layer.

• Back-haul: For cellular or digital wireless telephone networks. An 802.16 system may be a convenient means to provide wireless trunks for wireless telephony base stations.

• Frame relay: Similar to ATM. Frame relay uses variable-length frames in con- trast to the fixed-length cells of ATM.