System and method for improved pointing accuracy
First Claim
1. A method for transmitting data on a communication link between a first transceiver and a second transceiver in a free space optical communication network, the method comprising:
- transmitting on the communication link a plurality of data packets from the first transceiver;
transmitting from the first transceiver via in-band signaling a status packet comprising data indicative of an azimuth angle of the second transceiver;
receiving the plurality of data packet at the second transceiver;
retrieving the status packet from the plurality of data packets;
adjusting a characteristic of at least one transceiver based on the retrieved status packet.
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Accused Products
Abstract
A system and method for controlling the power of a transmitter helps to ensure that the transmitted signal is within the dynamic range of the intended receiver. The transmitted signal is received by the receiver. The received signal strength is measured to determine its power level in relation to the dynamic range of the receiver. Where the signal strength is too high, the transmitter is slewed to effectively decrease its pointing accuracy, thereby causing a lower-power portion of the transmitted signal to impinge upon the receiver. Similarly, where the signal strength falls below a desired level, the transmitter is slewed back toward the center-pointing position, effectively increasing its pointing accuracy, and thereby increasing the signal strength received at the receiver.
75 Citations
26 Claims
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1. A method for transmitting data on a communication link between a first transceiver and a second transceiver in a free space optical communication network, the method comprising:
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transmitting on the communication link a plurality of data packets from the first transceiver;
transmitting from the first transceiver via in-band signaling a status packet comprising data indicative of an azimuth angle of the second transceiver;
receiving the plurality of data packet at the second transceiver;
retrieving the status packet from the plurality of data packets;
adjusting a characteristic of at least one transceiver based on the retrieved status packet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for automatically aligning optical transceivers in a free space optical communication network including a first transceiver and a second transceiver aligned generally towards one another, the method comprising:
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determining at the second transceiver a characteristic of an optical communication signal received from the first transceiver;
transmitting from the second transceiver via in-band signaling a second optical communication signal including the characteristic of the optical communication signal and user data; and
adjusting one of an azimuth angle, an elevation angle, and a power level of the first transceiver based on the characteristic of the optical communication signal received from the second transceiver. - View Dependent Claims (13, 14, 15, 16, 17)
determining at the first transceiver a characteristic of a third optical communication signal received from the second transceiver;
transmitting from the first transceiver via in-band signaling a fourth optical communication signal including the characteristic of the third optical communication signal and user data; and
adjusting a characteristic of the second transceiver based on the characteristic of the third optical communication signal received from the first transceiver.
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18. A method for automatically tracking the movements of optical transceivers in a free space optical communication network including a first transceiver and a second transceiver aligned generally towards one another, the method comprising:
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transmitting from the first transceiver an optical communication signal;
receiving at the second transceiver the optical communication signal;
measuring at the second transceiver a signal strength of the optical communication signal;
transmitting from the second transceiver, via in-band signaling, a second optical communication signal comprising a status packet and user data, wherein the status packet includes an indication of the signal strength; and
adjusting an alignment of the first transceiver based on the status packet received from the second transceiver, wherein the act of adjusting an alignment comprises adjusting one of an elevation angle and an azimuth angle of the first transceiver. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
moving the first transceiver in a first direction;
re-measuring at the second transceiver the signal strength of the received optical communication signal;
transmitting from the second transceiver, via in-band signaling, an updated second optical communication signal including the re-measured signal strength;
moving the first optical transceiver in the first direction if the re-measured signal strength is determined to be higher than the measured signal strength; and
moving the first optical transceiver in a second direction if the re-measured signal strength is determined to be lower than the measured signal strength.
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21. The method of claim 20, wherein the act of moving the first optical transceiver in the first direction comprises adjusting an elevation angle of the first optical transceiver.
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22. The method of claim 21, wherein the act of moving the first optical transceiver in the second direction comprises adjusting an elevation angle of the first optical transceiver, wherein the second direction is opposite the first direction.
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23. The method of claim 20, wherein the act of moving the first optical transceiver in the first direction comprises adjusting an azimuth angle of the first optical transceiver.
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24. The method of claim 21, wherein the act of moving the first optical transceiver in the second direction comprises adjusting an azimuth angle of the first optical transceiver, wherein the second direction is opposite the first direction.
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25. The method of claim 20, further comprising:
repeating the acts of re-measuring, transmitting, determining, and moving the first optical transceiver.
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26. A free space optical communication system comprising:
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a first transceiver;
a second transceiver;
means for transmitting from the first transceiver an optical communication signal;
means for receiving at the second transceiver the optical communication signal;
means for measuring at the second transceiver a signal strength of the optical communication signal;
means for transmitting from the second transceiver, via in-band signaling, a second optical communication signal comprising a status packet and user data, wherein the status packet includes an indication of the signal strength; and
means for adjusting an alignment of the first transceiver based on the status packet received from the second transceiver, wherein the act of adjusting an alignment comprises adjusting one of an elevation angle and an azimuth angle of the first transceiver.
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Specification