The IEEE 802.16 Standard for Broadband Wireless Access

The IEEE 802.16 standard for broadband wireless access was recently approved . It defines a physical layer for systems operating at frequency bands between 10 and 66 GHz, a medium access control (MAC) protocol and the convergence layers for carrying protocols such as IP, ATM and Ethernet. An IEEE 802.16 system consists of a base station and one or more subscriber stations. The duplexing scheme is either TDD or FDD. In the FDD case there is seamless support of half-duplex subscriber stations. The transmissions in the downlink direction are done in a TDM fashion, with the possibility of introducing re-synchronization preambles to improve the statistical multiplexing in a deployment with half-duplex FDD terminals. The uplink operates in a TDMA fashion. Adaptive modulation is employed both in the uplink and the downlink. The MAC protocol is connection oriented and is capable of providing QoS. The MAC protocol utilizes variable length PDUs and is thus optimized to carry connectionless traffic such as IP and Ethernet while not sacrificing efficiency when carrying ATM. This paper discusses the main features of the standard with emphasis on the MAC protocol.