With its promise of a target transmission

range of up to 30 miles and a

target transmission rate of more

than 100 Mbps, WiMAX—the

commercialization of the evolving IEEE 802.16

standard—is the latest hot technology. A recent

amendment boosted the protocol’s mobility support,

making it even more attractive to roaming users.

The standard specifies both a common physical

layer and a media access control (MAC) layer

for WiMAX networks, but to make such networks

more usable and reliable, several security issues

must be addressed first. In this article, we introduce

the security protocols used in WiMAX networks

and discuss the problems they confront