Power and time saving initial tracebacks
US5490178A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 16, 1993 |
| Grant date | Feb 6, 1996 |
| Priority date | — |
| Expiry date | Nov 16, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/03178
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A digital communication system including a Viterbi decoder for tracing a path through a trellis of individual state information and method of operation are disclosed. The traceback determines a decoded symbol. A trellis of branch origin data is stored in an array of registers. The branch origin data associated with a symbol instant is a cell. Each cell of data is generated by execution of an update instruction form a digital signal process (DSP) to the coprocessor. A first predetermined traceback length is written to a traceback length register. The first predetermined traceback length is small to minimize tracebacks cycling into branch origin data from a previous transmission burst. A traceback is initiated by the DSP providing the coprocessor a single traceback instruction. The Viterbi decoder alternates between update and traceback instructions. At a predetermined symbol instant, the traceback length is increased to a second predetermined length by over-writing the traceback length register. The second predetermined length is selected relative to the predetermined symbol instant to assure tracebacks do not cycle into branch origin data from a previous transmission burst. After a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.