Mobile WiMAX Home

Mobile WiMAX, or IEEE 802.16e-2005, has emerged as a potential alternative to cellular technology for wide-area wireless networks. Based on OFDMA and approved by the International Telecommunications Union (ITU) as an IMT-2000 (3G technology) under the name OFDMA TDD WMAN (Wireless Metropolitan Area Network), mobile WiMAX has gained its greatest traction in developing countries as an alternative to wireline deployment.

Like GSM/UMTS, WiMAX is not a single technology; it is a family of interoperable technologies. Unlike GSM/UMTS, mobile WiMAX networks are not backward-compatible.

Mobile WiMAX employs many of the same mechanisms as HSPA to maximize throughput and spectral efficiency, including high-order modulation, efficient coding, adaptive modulation and coding, and Hybrid Automatic Repeat Request (HARQ). The principal differences from HSDPA are that mobile WiMAX uses OFDMA and is only standardized for TDD spectrum bands.

OFDM provides a potential implementation advantage for wide radio channels (for example, 20 MHz). In 5 to 10 MHz radio channels, there is no evidence indicating that mobile WiMAX will have any significant performance advantage on the downlink. Also, HSPA is commercially deployed in FDD spectrum bands, whereas mobile WiMAX’s is not standardized or deployed for TDD spectrum bands.

Although mobile WiMAX exploits significant radio innovations, it faces challenges like spectrum, economies of scale, and technology. Very few operators have access to 20 MHz of TDD spectrum for WiMAX that would permit them to provide widespread coverage. While GSM/UMTS/HSPA subscriptions today number in the billions, even by 2010, the number of WiMAX subscriptions is likely to be low.

Additional Resources

Questions and Answers

EDGE, HSPA, LTE: The Mobile Broadband Advantage (White paper written by Rysavy Research for 3G Americas, Sept 2007. PDF - 1 MB)