Pulse or digital communications – Systems using alternating or pulsating current – Plural channels for transmission of a single pulse train
Patent
1997-09-23
1999-12-21
Pham, Chi H.
Pulse or digital communications
Systems using alternating or pulsating current
Plural channels for transmission of a single pulse train
370468, 375240, H04K 110, H04L 2728
Patent
active
060058935
ABSTRACT:
A communications system employing the Discrete Multitone (DMT) line code divides the used frequency band W into a large number of subchannels, each with a bandwidth .DELTA.f=W/N. The signal in each subchannel is independently modulated at the symbol rate 1/.DELTA.f. Because of noise and the non-ideal characteristics of the transmission channel, the signal-to-noise ratio (SNR) varies for different subchannels across the frequency band. Each subchannel is used to transmit an integer number of bits in a two-dimensional signal constellation, the susceptibility to noise increasing with the size of the constellation assuming that the same signal energy is used. In order to use the transmission channel optimally, subchannels are assigned different numbers of bits depending on their specific SNR values, i.e., a subchannel with a high SNR value is assigned a large number of bits and vice versa. An optimal bit allocation is determined that ensures a certain bit error rate (BER) is obtained for all subchannels. In order to simplify numerical computations, thresholding is employed to make initial bit assignments. Further simplification of the bit loading procedures is obtained by ending bit allocation optimization efforts after a targeted BER is achieved.
REFERENCES:
patent: 5479447 (1995-12-01), Chow et al.
patent: 5497398 (1996-03-01), Tzannes et al.
patent: 5519730 (1996-05-01), Jasper et al.
patent: 5613035 (1997-03-01), Kim
patent: 5627937 (1997-05-01), Kim
patent: 5812599 (1998-09-01), Van Kerckhove
patent: 5852633 (1998-12-01), Levin et al.
IEEE Communications Magazine, May 1990, pp. 5-14, John A.C. Bingham, "Multicarrier Modulation for Data Transmission: An Idea Whose Time Has Come".
IEEE Transactions on Communications, vol. 43, No. 2/3/4, Feb./Mar./Apr. 1995, pp. 773-775, Peter S. Chow et al, "A Practical Discrete Multitone Transceiver Loading Algorithm for Data Transmission over Spectrally Shaped Channels".
Corrielus Jean B
Pham Chi H.
Telefonaktiebolaget LM Ericsson
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