Exalt Communications Inc.

Exalt Wireless, Inc.

Scientific Drilling International, Inc.

Proxim Corporation

Peter Smidth

Yongmin Zhang

Jean-Laurent Plateau

Venkateswara Rao Sattiraju

Jungji Yu

Matthew A White

Douglas Ridgway

Brian Daniel Gleason

Timothy Whitacre

Larry Joseph Schoennauer

Craig Solis

Stephen D Morrow

A method may include drilling a section of a first wellbore and casing a section of a first wellbore. The method may include lowering a downhole receiving system into the first wellbore to a first wellbore depth and drilling at least one section of a second wellbore. In addition, the method may include positioning an EM telemetry system in the at least one section of the second wellbore and transmitting an EM telemetry signal from the EM telemetry system. The method may include receiving the EM telemetry signal with the downhole receiving system.

Sub-surface electromagnetic telemetry systems and methods

A signal method may include obtaining a first set of signal measurements, processing the first set of signal measurements into a phase reference obtaining a second set of signal measurements, the second set of signal measurements varying as a function of the phase reference, detecting an item of interest using the second set of signal measurements and the phase reference, and using the item of interest.

Coherent measurement method for downhole applications

When a signal-to-noise ratio affecting radio communication becomes sufficiently low, then the data transmission rate is responsively decreased in compensation. The signal-to-noise ratio of the communication link is thereby increased. Data for multiple different services is transmitted in data packets between two radios. By allocating one part, or time slot, of the data packet's payload to one service, and allocating another part, or time slot, of the data packet's payload to another service, communications sessions for multiple services can be maintained concurrently. Services are prioritized relative to each other. In case the signal-to-noise ratio becomes too low, data packet portions that are related to lower-priority services can be omitted from some data packets before those data packets are transmitted. Data remaining in the packet can be sent at a reduced data transmission rate without causing the quality of service for the remaining packets to fall below the minimum required level.

Adaptive multi-service data framing

Techniques for minimizing latency and latency jitter in communication transmission systems are provided. In some embodiments, a first communication transmission system in a chain is configured to operate in accordance with a particular signal processing mode. Operating in accordance with the particular signal processing mode causes user data received in a first wireless signal to bypass a first set of one or more processing modules in an upstream receiver and a second set of one or more processing modules in a downstream transmitter. After the user data has bypassed the first and second set of processing modules, a second wireless signal that includes the user data is transmitted to a third communication transmission system in the chain. In other embodiments, the signal processing mode may be adaptively changed based on one or more conditions that are monitored along the chain.

Data communication over a frame synchronized digital transmission network

A multi-radio device system includes a set of sending radio devices and a set of receiving radio devices. Among the sending radio devices is a load-balancing radio device that receives data packets from an originating network. The load-balancing radio device labels data packets with sequence numbers and distributes the labeled data packets among the sending radio devices based on the relative capacities and statuses of those sending radio devices. The sending radio devices transmit the labeled data packets to the receiving radio devices. The receiving radio devices send the labeled data packets to an aggregating radio device within the set of receiving radio devices. The aggregating radio device uses the sequence numbers to ensure that the data packets are forwarded to a destination network in the correct order, extracting original data packets from the labeled data packets before forwarding the original data packets on toward the destination network.

Apparatus for Ethernet traffic aggregation of radio links

When a signal-to-noise ratio affecting radio communication becomes sufficiently low, the data transmission rate is responsively decreased in compensation. The signal-to-noise ratio of the communication link is thereby increased. Data for multiple different services is transmitted in data packets between two radios. By allocating one part, or time slot, of the data packet's payload to one service, and allocating another part, or time slot, of the data packet's payload to another service, communications sessions for multiple services can be maintained concurrently. Services are prioritized relative to each other. In case the signal-to-noise ratio becomes too low, data packet portions that are related to lower-priority services can be omitted from some data packets before those data packets are transmitted. Data remaining in the packet can be sent at a reduced data transmission rate without causing the quality of service for the remaining packets to fall below the minimum required level.

According to techniques described herein LO leakage may be automatically minimized in a transmitter chain, even though the leakage may be varying in nature. In an embodiment a target signal for transmission is received. An offset for reducing the effects of the LO leakage is applied to the target signal. After the offset is applied, the target signal is converted to a transmission signal using the LO. A power associated with the transmission signal is determined. The offset is then adjusted based on the power associated with the transmission signal. In another embodiment, the offset signal is adjusted in a manner that minimizes the power associated with the transmission signal.

Method and apparatus for minimizing local oscillator leakage in a transmitter

Apparatus for ethernet traffic aggregation of radio links

A method and apparatus for decoding a baseband signal of a radio signal removes, from the baseband signal, low-frequency and long-term noise that increases the possibility of decoding errors. The removal of low-frequency and long-term noise is performed by accumulating differences between the actual signal levels of the baseband signal and the expected signal levels for the baseband signal and subtracting the accumulated difference from the baseband signal before decoding. In one scheme, the baseband signal contains a predetermined training sequence of signal levels, where the differences between the actual signal levels of the baseband signal and the expected signal levels for the predetermined training sequence are accumulated. At the end of the training sequence, the accumulated training sequence difference is used as the accumulated difference and subtracted from the baseband signal, thereby providing stable operation for decoding signal levels that follow the training sequence.

Decision directed DC offset removal

The present invention provides methods and systems for allowing a receiver in a (wireless) communication system to synchronize its timing and frequency subsystems in accordance with a received signal. In accordance with one aspect, a method is provided in which a relative time of arrival of sync values provided in a received signal are determined and used to align the receiver's reference signal(s) accordingly. Other aspects of the invention will become apparent from the detailed description of exemplary embodiments that follows.

Method and apparatus for timing and/or frequency synchronization in an RF receiver

Radios synchronize their timing mechanisms using a timing signal that those radios propagate from one radio to another. Radios that are close to each other transmit only during times that none of the other nearby radios is trying to receive. In one scheme, a 'master' radio initiates communication while another 'slave' radio responds in a pre-determined manner. The master generates and propagates an inverted timing signal to the slave, which propagates approximately the same inverted timing signal to other radios in the slave's cluster. Each radio can be in one of three different modes: &#x201c;source,&#x201d; &#x201c;auto,&#x201d; and &#x201c;recipient&#x201d; modes. A &#x201c;source&#x201d; radio generates a timing signal independently. A &#x201c;recipient&#x201d; radio uses a received timing signal and forwards it to other radios. An &#x201c;auto&#x201d; radio behaves as a &#x201c;recipient&#x201d; radio while a timing signal is detectable, but behaves as a &#x201c;source&#x201d; radio if the timing signal is lost.

Automatic timing synchronization for wireless radio networks

A method and apparatus are provided that performs timing acquisition for multiple radio terminals. According to one aspect of the present invention the invention includes receiving a sequence of symbols modulated onto a carrier frequency over a channel and demodulating the symbols using a clock frequency. The invention further includes determining a frequency offset of the received symbols with respect to the clock frequency and applying the determined frequency offset to adjust the clock frequency.

Fast timing acquisition for multiple radio terminals

The present invention provides for cooling a plurality of racked electronic devices having a first electronic device having at least one cooling vent at a first end and a plurality of cooling holes at a top, each of the cooling vents having a cooling fan, means for flowing air through the cooling vent, means for outputting the air flow through a plurality of cooling holes on the top of the first electronic device. The present invention further provides for a second electronic device having a plurality of heat sink fins on the bottom. The bottom of the second electronic device coupled to the top of said first electronic device, means for aligning the plurality of cooling holes under the plurality of heat sink fins, and means for outputting the air through an output of the heat sink fins.

Growing community of inventors

San Luis Obispo, CA, United States of America

Peter Smidth