Coding and modulation for LMDS and analysis of the LMDS channel

Local Multipoint Distribution Service (LMDS) has the potential to become a viable alternative to coaxial cable, fiber and other wired and wireless tec hnologies providing "last mile" communication services. A major obstacle, h owever, is the high equipment cost. While for example cable modems supporti ng two-way services are available for $200 to $300, LMDS modem providing si milar services will cost over $1000. The major cost driver of LMDS equipmen t is the radio frequency (RF) unit, as Ka-band technology still is quite ex pensive. The modem design must minimize the overall architecture cost, and low-cost modems requiring an expensive architecture should not be used. The channel characteristics of LMDS systems are very different from those of f iber, coaxial cable, and lower frequency wireless links, major channel impa irments being non-linear high power amplifier (HPA), high phase noise and h igh co-channel interference. Modems should therefore be developed specifica lly for LMDS systems. This report deals with the choice of coding and modul ation schemes, the LMDS channel, and how the channel impairments should be overcome by digital signal processing algorithms.