US 6,154,871 A · Error detection and correction system for a stream of encoded data

Abstract

The invention provides a decoder of symbols of received data, the data being encoded according to a convolutional encoding scheme and transmitted through a communications channel. The data is punctuated according to a puncturing matrix, and has a plurality of state values which describe a sequence of state transitions. The decoder has a generation unit that accepts the received data for calculating metrics of the transitions thereof. A selector responsive to the generation unit selects a path of transitions corresponding to the path produced by a transmitter of the data stream. A traceback unit maintains historical information representative of sequential decision operations of the selector. A counter is provided for counting illegal state transitions of the path selected by the selector, and a control unit, responsive to the counter, determines a puncture rate and adjusts a puncture phase of the received data. The decoder can be used in a VLSI receiver circuit which is adapted to the reception of QPSK modulated data.

Claims9

Dependent claims

A decoder for received data symbols that are encoded according to a convolutional encoding scheme, the data being punctuated according to a puncturing matrix, the data having a plurality of state values and describing a sequence of state transitions from a first state to a succeeding state, wherein a path is defined by the sequence of state transitions, the decoder comprising:

a generation unit accepting said received data for calculating metrics of the transitions thereof from the first state to the succeeding state, wherein said metrics correspond to a likelihood that a measured path follows a path produced by an encoder of the data;
a selector responsive to said generation unit for selecting a path corresponding to the path produced by a transmitter of the data stream;
a traceback unit for maintaining historical information representative of sequential decision operations of said selector;
a resealing unit for resealing the metrics calculated in said generation unit to a non-negative number;
and
a control unit for determining a puncture rate and adjusting a puncture phase of the received data.

3 more elements

Dependencies are inferred from the claim text.

Error detection and correction system for a stream of encoded data

Life of this patent

Error detection and correction system for a stream of encoded data

Life of this patent

Abstract

Claims9