Lsi Logic Corporation

Lsi Logic Corporatino

Dariush Daribi

Advait Madhav Mogre

Daniel A Luthi

A method and system for compensating for code invariancies in a digital communication receiver is performed on demodulated signal data. A pre-Viterbi invariancy compensation is performed on the demodulated signal data to reverse a selected one of a number of possible transformations to create compensated signal data. The compensated signal data is then depunctured. The depunctured data is then decoded. An encoder encodes the decoded data. The encoded data and the depunctured data are then compared to determine equivalence. The pre-Viterbi invariancy compensation is performed to reverse a different one of the number of possible transformations to create the compensated signal data when the encoded data and the depunctured data are determined not to be equivalent. A post-Viterbi invariancy compensation is then performed on the decoded data to produce a set of compensated outputs. Thus, the post-Viterbi invariancy compensation reverses each one of the number of possible transformations on the decoded data. An output is then selected from between the set of compensated outputs and the decoded data in response to detection of a sync byte.

Method and system for automatic invariancy compensation in digital

A digital variable rate demodulator within a receiver operates close to the Nyquist rate. This serves to recover correct timing and filter adjacent channels. The samples of an incoming data signal are divided into phases and combined into phase vectors. Intermediate points within a given phase vector are determined by interpolation. The data is then converted into a weighted sum for the purpose of decimating down to the baud rate. The signal-to-noise ratio is then optimized by estimating the likelihood of occurrence of a given symbol within the waveform and filtering the near Nyquist data rate down to a one sample per symbol data rate.

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Fremont, CA, United States of America

Dariush Daribi