y bands serve as excellent candidates for broadband deployment. The most promising bands include 25GHz to 29.5GHz and 36GHz to 43.5GHz. In Europe, 3GHz of continu- ous bandwidth in the 40GHz to 43.5GHz band is reserved for Multimedia Wireless System (MWS). High-frequency BFWA requires line of sight, and the range is greatly affected by atmospheric conditions. The air interface standards for high- frequency BFWA include IEEE 802.16, ETSI HiperAccess, and DVB-Return Channel for Local Multipoint Distribution Service (LMDS). Mass-market penetration is hindered by the high cost of equipment (both base stations and user radio terminals), but the technology is available, and costs can be reduced. Low-frequency BFWA-Low-frequency BFWA is used mainly for data communications. These systems operate on frequencies between 2GHz and 11GHz. Lower frequencies, specifically around 2.4GHz, 3.5GHz, 5GHz, and 5.8GHz, use both licensed and unlicensed spectrum. Standards for low- frequency BFWA have developed procedures to allocate spectrum in a more efficient manner, introducing Orthogonal Frequency Division Multiplexing (OFDM) under non-line-of-sight conditions. This allows for more simulta- neous users, increased average throughput, security, and mobility. The main standards for low-frequency BFWA include IEEE 802.16a revised, IEEE 802.16e, WiBro, and ETSI HiperMAN. BFWA systems are serious competitors for full-service broadband access tech- nology. For an incumbent operator, high-frequency BFWA complements wired alternatives. For a new operator, it presents the opportunity to rapidly deploy an alternative broadband infrastructure. BFWA has numerous positive attributes. A radio multipoint network naturally supports broadcasting and multicasting ser- vices. It offers the flexibility of easy and rapid deployment, particularly with non- line-of-sight systems. BFWA requires low upfront investment because most of the cost lies in the user terminal. As traffic grows, the network can easily be expanded. BFWA can serve as a backup solution