Patent ID: 7061932
Filing Date: 2006-06-13
Classification: E21B,H04B

Abstract:
1. A downhole telemetry system that comprises: a first downhole transmitter that transmits a first uplink signal, wherein the first uplink signal is generated using amplitude modulation of a first uplink data stream onto a first code word signal; a second downhole transmitter that transmits a second uplink signal, wherein the second uplink signal is generated using amplitude modulation of a second uplink data stream onto a second code word signal, wherein the first and second code word signals are orthogonal; and an uphole receiver that receives a composite uplink signal including the first and second uplink signals in combined form, wherein the receiver is configured to extract the first and second uplink data streams from the composite uplink signal, wherein the first and second downhole transmitters are configured to adjust timing of the first and second code word signals, respectively, so as to provide synchronization of the first and second uplink signals at the uphole receiver.