Apparatus and method for efficient two-way optical communication where transmitter may interfere with receiver

• US 9,413,463 B2
• Filed: 09/02/2014
• Issued: 08/09/2016
• Est. Priority Date: 08/30/2013
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Bruneau, Jonathan S., Mathews, Jeffrey P., Taylor, Lee R.
• Primary Examiner(s): CURS, NATHAN M
• Application Number:
  US14/474,926
• Publication Number:
  US 20150063821A1
• Time in Patent Office: 707 Days
• US Class Current: 1/1
• CPC Class Codes: H04B 10/1143 Bidirectional transmission
• CPC Class Codes: H04B 10/116 Visible light communication
• CPC Class Codes: H04B 10/2507 for the reduction or elimination of distortion or dispersion
• CPC Class Codes: H04B 10/25891 Transmission components H04B10/40 takes precedence
• CPC Class Codes: H04B 10/40 Transceivers
• CPC Class Codes: H04B 10/502 LED transmitters

Abstract

An two-way optical communication apparatus, including a transmit element, a receive element, and a transceive processor. The transmit element is coupled to a light pipe, and transmits a first signal. The receive element is coupled to the light pipe, and receives a second signal. The transceive processor directs the transmit element to pause and then resume transmitting the first signal during first intervals, and directs the receive element to sample for the second signal during one or more second intervals within each of the first intervals, where the each of the first intervals is less than a first value and the first intervals occur at a duty cycle no greater than a second value, and where the first and second values are controlled by the transceive processor such that a user perceives the first optical signal as having a constant state for a third interval.

Claims

1. An apparatus for providing two-way optical communication, the apparatus comprising:

a transmit element, coupled to a light pipe, configured to transmit a first optical signal through said light pipe;

a receive element, also coupled to said light pipe, configured to receive a second optical signal through said light pipe;

an optical barrier, coupled to the light pipe, configured to at least partially isolate transmit and receive optical paths within split portions of the light pipe; and

a transceive processor, coupled to said transmit and receive elements, configured to direct said transmit element to suspend transmitting said first optical signal during a plurality of reception periods, and configured to direct said receive element to sample for said second optical signal during one or more sampling intervals within each of said reception periods,

wherein said each of the plurality of reception periods last for a duration of time no greater than 40 milliseconds, and the plurality of reception periods occur in the first optical signal at a duty cycle no greater than 10 percent.

2. The apparatus as recited in claim 1, wherein said first and second optical signals are at wavelengths in a range comprising the visible, ultraviolet, and infrared spectrums.

3. The apparatus as recited in claim 1, wherein said transmit element comprises a light emitting diode.

4. The apparatus as recited in claim 1, wherein said receive element comprises a phototransistor.

5. The apparatus as recited in claim 1, wherein the receive element is configured to sense an ambient light level of the surrounding environment during the reception periods, and the transceive processor employs an analog intensity value to adjust the durations of time and the duty cycles of the reception periods according to the sensed ambient light level.

6. The apparatus as recited in claim 1, wherein said transceive processor directs said transmit element to transmit optical data in the first optical signal during periods outside of the plurality of reception periods, and wherein said optical data is transmitted at a bit rate faster than a threshold optical data bit rate.

7. The apparatus as recited in claim 1, wherein said transceive processor directs said transmit element to transmit optical data in the first optical signal at a bit rate faster than a threshold optical data bit rate, but slower than that of said second optical signal.

14. The apparatus as recited in claim 7, wherein said transceive processor directs said transmit element to transmit optical data in the first optical signal at a bit rate faster than a threshold optical data bit rate.

8. An apparatus for providing two-way optical communication, the apparatus comprising:

a light pipe, configured to transport illumination from optical signals between ends of said light pipe;

a transmit element, coupled to a first one or said ends, configured to transmit a first optical signal through said light pipe to a second one of said ends;

a receive element, coupled to said light pipe, configured to receive a second optical signal transported through said light pipe from said second one of said ends;

an optical barrier, coupled to the light pipe, configured to at least partially isolate transmit and receive optical paths within split portions of the light pipe; and

a transceive processor, coupled to said transmit and receive elements, configured to direct said transmit element to suspend transmitting said first optical signal during a plurality of reception periods, and configured to direct said receive element to sample for said second optical signal during one or more sampling intervals within each of said reception periods,

wherein said each of the plurality of reception periods last for a duration of time no greater than 40 milliseconds, and the plurality of reception periods occur in the first optical signal at a duty cycle no greater than 10 percent.

9. The apparatus as recited in claim 8, wherein said first and second optical signals are at wavelengths in a range comprising the visible, ultraviolet, and infrared spectrums.

10. The apparatus as recited in claim 8, wherein said transmit element comprises a light emitting diode.

11. The apparatus as recited in claim 8, wherein said receive element comprises a phototransistor.

12. The apparatus as recited in claim 8, wherein the receive element is configured to sense an ambient light level of the surrounding environment during the reception periods, and the transceive processor employs an analog intensity value to adjust the durations of time and the duty cycles of the reception periods according to the sensed ambient light level.

13. The apparatus as recited in claim 8, wherein said transceive processor directs said transmit element to transmit optical data in the first optical signal during periods outside of the plurality of reception periods, and wherein said optical data is transmitted at a bit rate faster than a threshold optical data bit rate.

15. A method for providing two-way optical communication in a shared light pipe, the method comprising:

while, via a transmit element, transmitting a first optical signal through the shared light pipe;

suspending said transmitting during a plurality of reception periods, wherein said each of the plurality of reception periods last for a duration of time no greater than 40 milliseconds, and the plurality of reception periods occur in the first optical signal at a duty cycle no greater than 10 ; and

via a receive element, receiving a second optical signal through the shared light pipe during one or more sampling intervals within each of said reception periods, wherein an optical barrier is coupled to the light pipe, and configured to at least partially isolate transmit and receive optical paths within a split portion of the light pipe.

16. The method as recited in claim 15, wherein the first and second optical signals are at wavelengths in a range comprising the visible, ultraviolet, and infrared spectrums.

17. The method as recited in claim 15, wherein the transmit element comprises a light emitting diode.

18. The method as recited in claim 15, wherein the receive element comprises a phototransistor.

19. The method as recited in claim 15, wherein the receive element is configured to sense an ambient light level of the surrounding environment during the reception periods, and the transceive processor employs an analog intensity value to adjust the durations of time and the duty cycles of the reception periods according to the sensed ambient light level.

20. The method as recited in claim 15, further comprising:

transmitting optical data in the first optical signal during periods outside of the plurality of reception periods, and wherein said optical data is transmitted at a bit rate faster than a threshold optical data bit rate.

21. The method as recited in claim 15, further comprising:

transmitting said transceive processor directs said transmit element to transmit optical data in the first optical signal at a bit rate faster than a threshold optical data bit rate, but slower than that of said second optical signal.