Jay M Jacobsmeyer

US Patent:

55419550, Jul 30, 1996

Filed:

Apr 28, 1995

Appl. No.:

8/430268

Inventors:

Jay M. Jacobsmeyer - Colorado Springs CO

Assignee:

Pericle Communications Company - Colorado Springs CO

International Classification:

H04B 138

US Classification:

375222

Abstract:

An adaptive data rate modulator/demodulator (modem) (102), particularly useful for transmitting data over fading communications channels, uses an adaptive data rate technique which supports multiple data rates in the same device. The modem incorporates an adaptive data rate encoder (104) and an adaptive data rate decoder (105) using adaptive, parallel-branch decoding to translate received symbols into corresponding data bits. Significantly, the soft decision metrics of the decoder are also used to provide an estimate W of the signal-to-noise ratio. An optional predictor (232) receives W from the adaptive data rate decoder (105) and predicts the future signal-to-noise ratio to determine the desired data rate for the modem. The data rate is changed automatically and dynamically without interrupting the decoding process. A constant channel symbol rate and a single signal set simplify signal acquisition and synchronization.