Fade-resistant forward error correction method for free-space optical communications systems
US7277644B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 2003 |
| Grant date | Oct 2, 2007 |
| Priority date | — |
| Expiry date | Jun 24, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L1/0045
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Free-space optical (FSO) laser communication systems offer exceptionally wide-bandwidth, secure connections between platforms that cannot other wise be connected via physical means such as optical fiber or cable. However, FSO links are subject to strong channel fading due to atmospheric turbulence and beam pointing errors, limiting practical performance and reliability. We have developed a fade-tolerant architecture based on forward error correcting codes (FECs) combined with delayed, redundant, sub-channels. This redundancy is made feasible though dense wavelength division multiplexing (WDM) and/or high-order M-ary modulation. Experiments and simulations show that error-free communications is feasible even when faced with fades that are tens of milliseconds long. We describe plans for practical implementation of a complete system operating at 2.5 Gbps.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.