Pulse or digital communications – Systems using alternating or pulsating current – Plural channels for transmission of a single pulse train
Patent
1995-03-21
1997-06-03
Chin, Stephen
Pulse or digital communications
Systems using alternating or pulsating current
Plural channels for transmission of a single pulse train
375279, 375308, 370203, 370483, 348388, H04K 110
Patent
active
056362471
ABSTRACT:
A system for transmitting information over an OFDM channel using phase shift keying encoding employs a bit mapping encoder to reduce the crest factor (ratio of peak voltage to RMS voltage). For a 16 subchannel OFDM system using QPSK encoding, a first set of four symmetrically positioned pairs of subchannels is used to encode two bits of information on each subchannel. A second set of four symmetrically positioned pairs of subchannels is used to encode only one bit of information on each subchannel, with the resultant phasor for each pair of the second set of pairs of subchannels being orthogonal to the resultant phasor for one of the pairs of the first set of subchannels. With this arrangement, the crest factor is reduced.
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"Analysis and Simulation of a Digital Mobile Channel Using Orthogonal Frequency Division Multiplexing", by Leonard J. Cimini, Jr., IEEE Transactions on Communications, pp. 665-675, vol. COM-33, No. 7, Jul. 1985.
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"The Effect of Modulation on the Power Rating of Multi-Channel Linear Amplifiers", by D. W. Bennett, et al., pp. 322-333, University of Bristol, Lecture Notes in Computer Science 783.
Kamerman Adriaan
Krishnakumar Anjur S.
Chin Stephen
Le Amanda T.
Lucent Technologies - Inc.
Malvone Christopher N.
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