| 摘要 |
A modem employing feedback control coding to dynamically control signal-to-noise ratios and to identify errored codewords for retransmission. The receive path components of the modem include a signal-to-noise estimator, a feedback controller and a dynamic demapper. The signal-to-noise estimator repeatedly determines a difference between a target signal-to-noise ratio (SNR) and actual SNR in communications received from an opposing modem. A feedback controller responds to each determination by the signal-to-noise controller to send to the opposing modem a set of modified transmit control parameters for reducing the difference between the target and actual SNRs. The dynamic demapper dynamically alters constellation size or power spectral density for demapping communications received from the opposing modem responsive to a change in transmission parameters thereof resulting from the modified set of transmit control parameters.
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