Method and system for multirate multiuser modulation
US7139237B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 2001 |
| Grant date | Nov 21, 2006 |
| Priority date | — |
| Expiry date | Jul 10, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2201/70703
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A multi-rate interleaved frequency division multiple access (IFDMA) modulation scheme permits users to transmit at different data rates or to vary their data rates while providing frequency diversity and preserving low peak-to-average power ratios and orthogonality between users at different data rates. The modulation scheme allows user-specific data block and repetition sizes, as well as user-specific modulation codes. Code assignment rules are provided for maintaining orthogonality between users having different data rates. Block and phase ramp modulation codes can be used. Asynchronous transmissions by users are supported by ensuring that the length of the cyclic extension is sufficiently long to tolerate worst case relative signal arrival delays between users and the channel pulse response duration over the communication medium. The modulation scheme can be employed in wireless communication systems, such as cellular or paging systems.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.