Pulse or digital communications – Transceivers – Modems
Patent
1995-07-24
1997-06-17
Chin, Stephen
Pulse or digital communications
Transceivers
Modems
375261, 375324, 375340, 379 98, 329304, H04B 138
Patent
active
056404174
ABSTRACT:
A cellular subscriber modem for receiving CCITT-type quadrature amplitude modulated (QAM) signals. The cellular modem includes a novel symbol detector that converts received symbol information to polar notation. The detector's constellation thresholds include a circular threshold having a radius greater than the magnitude of the innermost symbols, but less than the magnitude of the outermost symbols, and radially spaced thresholds, which further discriminate between the outermost symbols. As a result, special cellular-compatible modem equipment need not be connected between the public-access switched telephone network and the computer equipment at the other end, which means that a CCITT-compatible cellular subscriber modem can then be treated as any other type of CCITT-modem. The detector may be implemented in the software of a standard modem processor, or as several analog comparator circuits.
REFERENCES:
patent: 3878468 (1975-04-01), Falconer et al.
patent: 4679227 (1987-07-01), Hughes-Hartogs
patent: 4697281 (1987-09-01), O'Sullivan
patent: 4731816 (1988-03-01), Hughes-Hartogs
patent: 4811363 (1989-03-01), Hoffmann
patent: 4837800 (1989-06-01), Freeburg et al.
patent: 4849996 (1989-07-01), Kamerman
patent: 4912728 (1990-03-01), Deguchi
patent: 4912756 (1990-03-01), Hop
patent: 4984219 (1991-01-01), Brown et al.
patent: 4991197 (1991-02-01), Morris
patent: 5020090 (1991-05-01), Morris
patent: 5103459 (1992-04-01), Gilhousen et al.
patent: 5128934 (1992-07-01), Jasuski
patent: 5157693 (1992-10-01), Lemersal, Jr. et al.
patent: 5265151 (1993-11-01), Goldstein
patent: 5535244 (1996-07-01), Nakatsu et al.
Patrick Dryden, "PCs Phone Home: Cellular, Radio Links", Feb. 19, 1990 pp. 31 and 39.
Narayan, McLane, "Fractionally Spared Equalization for Analog Cellular Data Modems", IEEE, May 9, 1991.
Webb, "QAM: the Modulation Scheme for Future Mobile Radio Communications", Electronics & Communication Engineering Journal, Aug. 1992.
Taub & Schilling, "Principles of Communication Systems" 1986, pp. 272-276.
Sampei, S., "Rayleigh Fading Compensation Method for 16QAM MODEN in Digital Land Mobile Radio Systems," Electronics and Communications in Japan, Part I, vol. 73, No. 2, 1990, pp. 99-108
Wood, S.L., Larimore, M.G. and Treichler, J.R., "Modem Constellation Identification: A Performance Comparison of Two Methods," Institute of Electrical and Electronic Engineers, 2847-2/90/0000-1651, 1990.
Liu, C. and Feher, K., "Performance of Non-Coherent .pi./4-QPSK in a Frequency-Selective Fast Rayleigh Fading Channel," IEEE International Conference on Communication (ICC 1990), Part IV, Apr. 16-19,1990, pp. 1369-1373.
Journal, 1990 (Exact date unknown), p. B1.
Barabash Darrell W.
McGrath Alan D.
McRory John G.
Chin Stephen
Harris Canada Inc.
Le Amanda T.
LandOfFree
QAM detector which compensates for received symbol distortion in does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with QAM detector which compensates for received symbol distortion in, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and QAM detector which compensates for received symbol distortion in will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2163600