Reduced search symbol estimation algorithm
US6597743B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 7, 1999 |
| Grant date | Jul 22, 2003 |
| Priority date | — |
| Expiry date | Dec 7, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M13/3955
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A reduced search symbol estimation algorithm includes a forward recursion, a backward recursion, and a combining step. To reduce complexity, during the forward and backward recursions, the number of survivor states retained at each stage is less than the total number of states of the trellis. The survivor states are selected from a group of candidate states, that are connected by branches to survivors from the previous stage of the recursion. The decoder compares the accumulated path metrics for each candidate state and retains a specified number of states that is less than the total possible number of states. For the forward recursion, the retained states or survivor states, denoted as Qk, are stored along with the corresponding state metrics. For the backward recursion, the retained states, denoted as Rk, are stored along with the corresponding state metrics. During the combining step, the computation of a soft value is restricted to branches (s′,s) connecting survivor states s′ and s in the forward and backward recursions respectively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.