Radiotelephone system employing digitized speech/data signalling
US4876740A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 13, 1989 |
| Grant date | Oct 24, 1989 |
| Priority date | — |
| Expiry date | Feb 13, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/10
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A cellular radiotelephone system is disclosed in which the signalling protocol for the system is embedded in the frame synchronization of the digital messages transmitted on the system. Multiple functions are accomplished by the synchronization signal and include call supervision, mode definition, and data frame synchronization. The synchronization signal is a high auto correlation, low cross correlation sequence of a predetermined number of data bits. Different bit sequences may be employed as a synchronization signal while conveying call supervision information defining the serving fixed site. Additionally, the logical inverse of the synchronizing signal may be utilized interchangably with the synchronizing signal to define the fixed site. A repetitive pattern of synchronizing signals and logical inverse synchronizing signals convey system mode information without increasing signalling overhead or losing the correlation performance of the full synchronization word.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.