SIGNAL TRANSMISSION APPARATUS AND OPTICAL MODEM MODULATION METHOD
First Claim
1. A modulation method for an optical modem comprising:
- providing, by an optical interface, a signal to a light source;
receiving, by a photo detector, light reflected by an optical link when light output from the light source based on the provided input signal is reflected by the optical link;
determining, by the photo detector, an characteristic of the optical link using the reflected light; and
determining, by the optical modem, a power level and a modulation method for each subcarrier based on the determined characteristic of the optical link.
1 Assignment
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Accused Products
Abstract
A modulation method of an optical modem and a signal transmission apparatus performing the method are disclosed. The modulation method of the optical modem includes an optical interface providing a signal to a light source, a photo detector receiving reflected light by an optical link when output light from the light source based on the provided signal is reflected by the optical link, the photo detector measuring and determining characteristics of the optical link using the reflected light, and the optical modem determining a power level and a modulation method for each subcarrier based on the characteristics of the optical link.
6 Citations
17 Claims
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1. A modulation method for an optical modem comprising:
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providing, by an optical interface, a signal to a light source; receiving, by a photo detector, light reflected by an optical link when light output from the light source based on the provided input signal is reflected by the optical link; determining, by the photo detector, an characteristic of the optical link using the reflected light; and determining, by the optical modem, a power level and a modulation method for each subcarrier based on the determined characteristic of the optical link. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A signal transmission apparatus comprising:
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a light source to emit an output light; an optical interface to provide a signal so that the light source emits the output light; an optical splitter to change an optical path of light reflected by an optical link when the output light emitted from the light source is reflected by the optical link; a photo detector to receive the light reflected by the optical link, transmitted from the optical splitter and to determine characteristics of the optical link; and an optical modem to determine a power level and a modulation method for each OFDM subcarrier based on the characteristics of the optical link. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A modulation method of an optical modem included in an optical line terminal (OLT) or an optical network unit (ONU) consisted of an orthogonal frequency division multiple access-passive optical network (OFDMA-PON), the modulation method comprising:
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emitting, by a light source, an output light; determining, by a photo detector, a length and a loss characteristic of an optical fiber included in an optical link through which the output light is transmitted; and controlling, by an optical modem, a power level and a bit allocated to a subcarrier for an optical OFDM signal based on the length and the loss characteristic of the optical fiber. - View Dependent Claims (16, 17)
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Specification