Downhole telemetry system having discrete multi-tone modulation with QAM fallback
US7443312B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 8, 2004 |
| Grant date | Oct 28, 2008 |
| Priority date | — |
| Expiry date | Jul 28, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2601
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Improved communication systems and methods are disclosed. In one embodiment, a downhole communications system comprises a downhole transceiver and a surface transceiver. The surface transceiver receives a discrete multi-tone (DMT) modulated uplink signal from the downhole transceiver, and transmits a downlink signal to the downhole transceiver using a modulation method determined by the transceivers as communications are initiated. The downlink modulation methods supported by the surface transceiver may include DMT modulation and quadrature amplitude modulation (QAM). The modulation mode selection may be based on measured channel characteristics, on proposed data rates, or on other predetermined parameters. The uplink and downlink signals may be communicated over a shared transmission mode on multiconductor cable or wired pipe, and alternatively the uplink and downlink signals may be communicated over separate transmission modes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.