X Development LLC

Bruce Moision

Baris Ibrahim Erkmen

Devin Brinkley

Edward Allen Keyes

Paul Csonka

Oliver Edward Bowen

Travis Lantz

An optical communication system includes an optical transmitter and one or more processors. The optical transmitter is configured to output an optical signal, and includes an average-power-limited optical amplifier, such as an erbium-doped fiber amplifier (EDFA). The one or more processors are configured to receive optical signal data related to a received power for a communication link from a remote communication system and determine that the optical signal data is likely to fall below a minimum received power within a time interval. In response to the determination, the one or more processors are configured to determine a duty cycle of the optical transmitter based on a minimum on-cycle length and a predicted EDFA output power and operate the optical transmitter using the determined duty cycle to transmit an on-cycle power that is no less than the minimum required receiver power for error-free operation of the communication link.

Optical amplifier burst mode communication with variable duty cycle

The disclosure provides a communication system that includes sensors, a plurality of components, and processors. The sensors receive measurements related to a state of the communication system. The processors receive an indication of an amount of received power at a remote communication system and estimate a state of the plurality of components based on the received one or more measurements and the received indication. Using the indication and the estimated state, the processors determine whether the amount of received power is likely to fall below a minimum received power within a given time interval. When it is likely, the processors select an adjustment technique of a plurality of adjustment techniques for adjusting a data rate of the outbound signal and adjust a given component of the communication system using the selected adjustment technique to change the data rate of the outbound signal.

Adaptive rate modem

The disclosure provides for a communication system that includes one or more sensors and one or more processors. The one or more processors are configured to receive, during a first timeframe, a first indication of an error rate of a communication link, a second indication of an amount of received power at a remote communication system, and one or more measurements related to the state of the communication system. The one or more processors are then configured to estimate a plurality of disturbance values to the communication system according to the one or more measurements and the second indication. Each disturbance value is associated with a set of components of the communication system. The one or more processors are configured to adjust a beam divergence of a beacon beam or a communication beam transmitted from the communication system based on the plurality of disturbance values and the first indication.

Beam divergence adjustment of a communication beam based on state disturbance estimations

The disclosure may provide for a communication method and system. A transmitter of the communication system may include an interleaver and a first encoder for determining parity bits. The transmitter also may include a multiplexer for joining the parity bits with the data. A second encoder may be positioned after the multiplexer for implementing an error correcting code. A receiver of the communication system may include a decoder followed by an interleaver. When errors are detected in received data at the decoder, one or more processors of the receiver may be configured to correct portions of the received data and combine the corrected portions with the received data.

Communication method and system with on demand temporal diversity

Aspects of the disclosure provide techniques for automatic repeat request (ARQ) in a free-space optical communication (FSOC) architecture. These techniques, including block-selective ARQ, adaptive retransmission delay, and random seed scrambling, can be used individually or in combination to combat problems involving frame loss or corruption. These techniques enable the system to rapidly recover by streamlining the retransmission process. For instance, block-selective ARQ acknowledges variable length blocks of frames in the return stream from the receiver to the transmitter. Adaptive retransmission delay allows the retransmission delay to grow in the absence of feedback by the receiver, up to some defined limit. And with random seed sampling, a scrambling sequence is incorporated to aid with frame syncing, which avoids the need for a line code. These aspects of the technology provide a robust communication process, and also reduce overhead costs associated with unnecessary retransmissions.

Efficient automatic repeat request for free space optical communication

A data rate at which data can be transmitted is adapted in real-time to power fluctuations. Bits of data to be sent by a transmitter are mapped to physical symbols, where a first modulation uses a first number of bits per pulse and a second modulation uses a second number of bits per pulse. Both modulations are sent, with one nested inside the other. A receiver decodes one or both bit streams, depending on a signal to noise ratio (SNR). In this regard, the data rate traces the received power, and higher data rates may be used despite periods of power fluctuations. This technique enables rapid, or even instantaneous, changes by using nested modulation. Moreover, a fast feedback mechanism is used to inform the transmitter when to change its modulation and to retransmit bits lost during an initial transmission.

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Palo Alto, CA, United States of America

Bruce Moision