EP0281306A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A technique for repelling carriers in optical communications to minimize mutual interference
Assignee: AT&T Inc
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Filing: 1988-02-24
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Granted: —
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Expires: 2008-02-24
Abstract
Abstract The present invention relates to a technique for repelling carriers in a Frequency Division Multiplexed (FDM) lightwave communication system to minimize mutual interference between signals. The system comprises a plurality of transceivers (20), each comprising a transmitter section (30) and a receiver section (40) which is coupled to a separate user of the system on one side, and on the other side to a lightwave communication arrangement (21-23) that interconnects the plurality of transceivers. Each of the transmitter sections of the system uses a separate carrier (10-14) for transmitting an associated users' information signal, and, during each sequential test cycle period, slowly dithers this carrier in random order to a first nearby frequency (50), on one side of the nominal carrier frequency, and then to a second nearby frequency (51) on the other side of the nominal carrier frequency. Each receiver section monitors and measures the background interference at each of the first and second nearby side frequencies of the desired channel and sends a control signal back to the associated transmitter section to move the frequency of its carrier to the nearby side frequency indicating the least noise for the next testing cycle where the above technique is repeated.
Inventors
- 👤 Gerard Joseph Foschini
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 07:29
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/50; H04B10/501; H04B10/503; H04B10/504; H04B10/40; H04B10/505; H04B10/506; H04B10/516; H04B10/572; H04L; H04L5/00; H04L5/02; H04L5/06
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
138 words
A transceiver for use in a frequency division multiplexing (FDM) lightwave communication system, the transceiver comprising: a transmitter section (30) including; means (31) for generating a predetermined nominal lightwave carrier signal; and means (33-35) for modulating the nominal lightwave carrier signal from the generating means with an information signal to be transmitted from the transmitter section to a remote transceiver; CHARACTERIZED IN THAT the transceiver further comprises: means (32) for generating control signals to the generating means for causing said generating means to slowly dither the nominal lightwave carrier signal to a first nearby carrier frequency on one side of the nominal carrier signal in a manner that enables the collective background interference to be sensed by a received for deriving a control signal to reposition the carrier and situate the carrier more favorably amid the background interference.
Claim 2
Dependent Claim
138 words
A transceiver for use in a frequency division multiplexing (FDM) lightwave communication system, the transceiver comprising: a transmitter section (30) including; means (31) for generating a predetermined nominal lightwave carrier signal; and means (33-35) for modulating the nominal lightwave carrier signal from the generating means with an information signal to be transmitted from the transmitter section to a remote transceiver; CHARACTERIZED IN THAT the transceiver further comprises: means (32) for generating control signals to the generating means for causing said generating means to slowly dither the nominal lightwave carrier signal to a first nearby carrier frequency on one side of the nominal carrier signal in a manner that enables the collective background interference to be sensed by a received for deriving a control signal to reposition the carrier and situate the carrier more favorably amid the background interference.
Claim 3
Dependent Claim
157 words
A transceiver according to claim 1 wherein the transceiver further comprises: a receiver section CHARACTERIZED IN THAT the receiver section comprises: a receiver, responsive to a lightwave information signal transmitted by the remote transceiver which modulated a second nominal lightwave carrier signal with an information signal destined for the receiver section while slowly dithering the second lightwave carrier signal, for demodulating the received lightwave information signal for transmission to an assoicated user of the system and operating on the demodulated information signal for generating a separate output signal from which corrective movement of the carrier can be effected, and a processor responsive to the output signals from the receiver for determining an indicator of the interference level and for generating a control signal to effect corrective movement to a frequency with a lower interference level for transmission to the modulating means of the transmitter section for transmission back to the remote transceiver in the modulated information signal.
Claim 4
Independent Claim
182 words
A method of transmitting signals in a frequency division multiplexed (FDM) lightwave communication system, the method comprising the steps of: at a first transceiver associated with a first user of the system, (a) generating a nominal lightwave carrier signal and; (b) modulating the nominal carrier lightwave signal with an information signal received from the first user; CHARACTERIZED IN THAT the method comprises the further steps of: (c) slowly dithering the nominal carrier lightwave signal generated in step (a) in a neighborhood of the nominal lightwave carrier signal of the first user; and at a remote second transceiver associated with a second user, (d) demodulating the modulated information signal received from the first transceiver for transmission to the second user, and sequentially sampling the demodulated information signal so as to generate control signals promoting favorable repositioning of the carrier; and (e) transmitting a carrier control signal back to the first transceiver for moving the nominal carrier frequency generated in step (a) to a nearby carrier frequency derivable from the carrier control signal before reiterating steps (b) to (e) during a next cycle period.
Claim 5
Independent Claim
182 words
A method of transmitting signals in a frequency division multiplexed (FDM) lightwave communication system, the method comprising the steps of: at a first transceiver associated with a first user of the system, (a) generating a nominal lightwave carrier signal and; (b) modulating the nominal carrier lightwave signal with an information signal received from the first user; CHARACTERIZED IN THAT the method comprises the further steps of: (c) slowly dithering the nominal carrier lightwave signal generated in step (a) in a neighborhood of the nominal lightwave carrier signal of the first user; and at a remote second transceiver associated with a second user, (d) demodulating the modulated information signal received from the first transceiver for transmission to the second user, and sequentially sampling the demodulated information signal so as to generate control signals promoting favorable repositioning of the carrier; and (e) transmitting a carrier control signal back to the first transceiver for moving the nominal carrier frequency generated in step (a) to a nearby carrier frequency derivable from the carrier control signal before reiterating steps (b) to (e) during a next cycle period.
References Cited (Backward Citations)
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