2 Generation Broadband Systems

Second-generation broadband wireless systems were able to overcome the LOS issue and to pro-vide more capacity. This was done through the use of a cellular architecture and implementation of advanced-signal processing techniques to improve the link and system performance under multipath conditions. Several start-up companies developed advanced proprietary solutions that provided significant performance gains over first-generation systems. Most of these new sys-tems could perform well under non-line-of-sight conditions, with customer-premise antennas typically mounted under the eaves or lower.

Many solved the NLOS problem by using such tech-niques as orthogonal frequency division multiplexing (OFDM), code division multiple access (CDMA), and multiantenna processing. Some systems, such as those developed by SOMA Net-works and Navini Networks, demonstrated satisfactory link performance over a few miles to desktop subscriber terminals without the need for an antenna mounted outside. A few megabits per second throughput over cell ranges of a few miles had become possible with second-generation fixed wireless broadband systems.