Method to minimize compatibility error in hierarchical modulation
US7215713B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 22, 2004 |
| Grant date | May 8, 2007 |
| Priority date | — |
| Expiry date | Jan 17, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/3488
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
The present invention involves a method and system for transmitting two levels of data in a hierarchical transmission schema. A first modulated signal is generated based on first input. A second modulation signal is generated based on a second input that has a data rate that is a fraction of the data rate of the first modulated signal. The second modulation signal has known instances where the second modulation signal has no energy. In a system where the first modulation is quadrature phase shift keying (QPSK), the second modulation signal can be a secondary phase offset. A receiver in the system that has a priori knowledge about the timing relationship between the first data signal and the instances when the second data signal is present will be able to detect both data signals optimally.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.