Data transmission
US4829526A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 4, 1986 |
| Grant date | May 9, 1989 |
| Priority date | — |
| Expiry date | Nov 4, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L1/188
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An adaptive system for binary data compression incorporating a coding scheme which is simple to implement, which limits codeword length and which can be implemented by software. Data compression is achieved by assigning four bit codes to the eight most frequently occurring characters in the data and eight or nine bit codes to the remaining characters wherein the code assignment is made according to a continuously updated evaluation of character frequency distribution. Run length encoding may be used in conjunction with this technique, to achieve further data compression. For transmission, error control protocols are applied to the compressed data where such protocols may include the use of forward error correcting (FEC) coding and an automatic repeat request (ARQ) system. The data may be transmitted using a burst error control system based on interleaving so that a single error correcting FEC coding can corrects bursts of errors characteristic of a telephone system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.