Circuit for decoding convolutional codes for executing the survivor path storage and reverse scanning stage of a Viterbi algorithm
US5257263A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 26, 1991 |
| Grant date | Oct 26, 1993 |
| Priority date | — |
| Expiry date | Jun 26, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M13/41
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
In a circuit for decoding convolutional codes for executing the survivor path storage and reverse scanning stage of a Viterbi algorithm, decoding consists in reverse scanning a plurality of paths of a trellis representing a diagram of the possible transitions resulting from encoding by an encoder comprising .nu. flip-flops, each node of the trellis being represented by a word on N=2.sup..nu. bits. The circuit selects from a plurality of possible survivor paths that which has the lowest metric, so as to reconstitute the trellis path actually determined by the encoding process and to recover the sequence of information bits that caused this path to be adopted. The circuit comprises a memory storing a plurality of said words of N=2.sup..nu. bits and, connected to the output of said memory, a cascade of .nu. groups of 2-in-1 multiplexers progressively combining the 2.sup..nu. outputs of the memory into a single output, a D flip-flop being provided at the output of each multiplexer. The final single flip-flop delivers sequentially the information bits representing the required path and the select signal of each multiplexer is the output signal of said final flip-flop.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.