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Coding and Modulation for LMDS and Analysis of the LMDS Channel



J E. Hakegard


During the last two to three years, there has been considerable activity aimed towards deploying broadband wireless access systems. The U. S. Local Multipoint Distribution Services (LMDS) auctions in February-March 1998 of 1.3 GHz of spectrum between 27.5 GHz and 31.3 GHz triggered efforts to develop system solutions and standards, whose objective is to render LMDS systems competitive to other broadband, and primarily wireline, technologies. The modem design must be matched to the channel characteristics of LMDS systems, which are very different from those of coax and even lower frequency wireless communications systems. In addition, the cost factor is a key issue to face the competition from other technologies. A modem design meeting these two constraints is described in this paper, together with an analysis of the main impairments characterizing the LMDS channel. The modem includes fully rotational invariant trellis coded modulation (TCM), amplitude phase modulation (APM), equalization and predistortion.
Journal of Research (NIST JRES) -
105 No. 5


co-channel interference, Ka-band channel, LMDS, modem design, non-linear HPA, pragmatic TCM


Hakegard, J. (2000), Coding and Modulation for LMDS and Analysis of the LMDS Channel, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD (Accessed July 22, 2024)


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Created October 1, 2000, Updated February 19, 2017