Data symbol estimation
US5185747A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 6, 1992 |
| Grant date | Feb 9, 1993 |
| Priority date | — |
| Expiry date | May 6, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/03318
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A method of estimating a digitized data signal transmitted as a sequence of data symbols. The received signal is generally distorted by transmission through a dispersive communications channel. The received symbols can exist in a plurality of different states depending on the number of symbols in the data alphabet and the extent of intersymbol interference. In the present method a near-instaneous soft decision is made (without the need for memory storage) for each estimated symbol using the following main steps. 1) Determine for each state at a given time increment k the respective partial path metric (M.sub.A) in respect of the state transition corresponding to the transmission of a first symbol type (A). 2) Determine for each state at the same time increment k the respective partial path metric (M.sub.B) in respect of the state transition corresponding to the transmission of a second symbol type (B). 3) Select the maximum value (M.sub.Amax and M.sub.Bmax) of the first and second symbol type partial path metrics. 4) Difference the two maximum values at step 3 to yield an estimate of the transmitted data symbol in the form of a soft decision. The soft decision has the advantage tha…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.