Second Generation Broadband Systems

Second-generation broadband wireless systems were able to overcome the LOS issue and to provide
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 systems
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 techniques
as orthogonal frequency division multiplexing (OFDM), code division multiple access
(CDMA), and multiantenna processing. Some systems, such as those developed by SOMA Networks
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 secondgeneration
fixed wireless broadband systems.