Synchronization sequence decoder for a digital radiotelephone system
US4649543A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 30, 1985 |
| Grant date | Mar 10, 1987 |
| Priority date | — |
| Expiry date | Aug 30, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/10
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A decoding system and method is disclosed for a radiotelephone system carrying digital messages. A set of multibit high auto-correlation, low cross-correlation synchronization words and their ones complement inverses are employed for message synchronization and supervisory functions. System state communication is achieved by utilizing a sequence of normal synchronization words and their ones complement inverses. Reliability of the coding is achieved by detecting normal or inverse words as binary levels when fewer than a predetermined number of bit errors exist in the bit sequence. If the predetermined number of bit errors is exceeded, a selected binary one or zero is substituted. This selected sequence of binary levels is decoded and the Hamming distance between a masked decoded sequence and a masked selected sequence is calculated. If the Hamming distance calculated yields a number less than or equal to a number equal to the synchronization error correction capability of the coding function, the decoded sequence is accepted as correct. If the Hamming distance calculation yields a number greater than the error correction capability value, a new set of substituted binary levels is t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.