State metrics memory reduction in a turbo decoder implementation
US9077384B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 15, 2012 |
| Grant date | Jul 7, 2015 |
| Priority date | — |
| Expiry date | Oct 24, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M13/6505
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Methods and apparatus are described for reducing memory storage cells in a turbo decoder by storing only half the state metrics generated during a scan process. States associated with each bit transmission may be divided into couples and only one state from every state couple may be stored. In one example embodiment, only the state metric for a losing state of every state couple is saved, along with a single bit, e.g., 1 or 0, indicating whether the upper state or lower state of the state couple was the winner. The winning state may be reconstituted at a later stage. In this manner, for a code rate 1/3 and constraint length 3 turbo code, instead of storing 8*10=80 bits of state metrics for each systematic bit, only (4*10)+(4*1)=44 bits of scan state metrics data need be stored, a savings of nearly 50% regardless of the transistor technology used.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.