Basic data on IEEE 802.16 Standards

Attributes	802.16	802.16d-2004	802.16e-2005
Status	Completed December 2001	Completed June 2004	Completed December 2005
Frequency band	10GHz–66GHz	2GHz–11GHz	2GHz–11GHz for fixed; 2GHz–6GHz for mobile applications
Application	Fixed LOS	Fixed NLOS	Fixed and mobile NLOS
MAC architecture	Point-to-multipoint, mesh	Point-to-multipoint, mesh	Point-to-multipoint, mesh
Transmission scheme	Single carrier only	Single carrier, 256 OFDM or 2048 OFDM	Single carrier, 256 OFDM or scalable OFDM with 128, 512, 1024, or 2048 subcarriers
Modulation	QPSK, 16 QAM, 64 QAM	QPSK, 16 QAM, 64 QAM	QPSK, 16 QAM, 64 QAM
Gross data rate	32 Mbps – 134.4 Mbps	1 Mbps–75 Mbps	1 Mbps–75 Mbps
Multiplexing	Burst TDM/TDMA	Burst TDM/TDMA/ OFDMA	Burst TDM/TDMA/ OFDMA
Duplexing	TDD and FDD	TDD and FDD	TDD and FDD
Channel bandwidth	20MHz, 25MHz, 28MHz	1.75MHz, 3.5MHz, 7MHz, 14MHz, 1.25MHz, 5MHz, 10MHz, 15MHz, 8.75MHz	1.75MHz, 3.5MHz, 7MHz,14MHz, 1.25MHz, 5MHz, 10MHz,15MHz, 8.75MHz
WiMAX implementation	None	256 - OFDM as Fixed WiMAX	Scalable OFDMA as Mobile WiMAX

SALIENT FEATURES OF WiMAX

WiMAX is a wireless broadband solution that offers a rich set of features with a lot of flexibility in terms of deployment options and potential service offerings. Some of the salient features that deserve highlighting are:

1. OFDM-based physical layer
2. Very high peak data rates
3. Scalable bandwidth and data rate support
4. Adaptive Modulation and Coding (AMC)
5. Link-layer retransmissions
6. Support for Time Division Duplex (TDD) and Frequency Division Duplex (FDD)
7. Orthogonal Frequency Division Multiple Access (OFDMA)
8. Flexible and dynamic per user resource allocation
9. Support for advanced antenna techniques
10. Quality of Service (QoS) support
11. Robust security
12. Support for mobility
13. IP-based architecture