# US 9,520,951 B2 · Signal transmission method, transmitter, and signal transmission system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,951 B2 - Document ID: US9520951B2 - Status: Granted - Kind: B2 - Application number: 14/569,417 - Filed: 2014-12-12 - Published: 2015-04-09 - Granted: 2016-12-13 - Earliest claimed: 2012-06-14 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Zhaohui Li; Linghao Cheng; Ke Wang - Web page: https://patentgrep.com/patent/US9520951B2 ## CPC - H04B 10/564: Power control - H04B 10/0775: {Performance monitoring and measurement of transmission parameters} - H04B 10/0779: {Monitoring line transmitter or line receiver equipment} - H04L 25/022: {of frequency response} - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Embodiments of the present invention relate to a signal transmission method, transmitter, and signal transmission system. The method includes: obtaining, by a sending end, information about a power fading point of a fiber channel between the sending end and a receiving end; determining, by the sending end and according to the information about the power fading point, a subcarrier that is used to send a service signal to the receiving end on the fiber channel, where a frequency of the determined subcarrier is different from that of the power fading point; and sending, by the sending end, a service signal to the receiving end by using the determined subcarrier. According to the embodiments of the present invention, validity of a signal spectrum is ensured, and therefore it is ensured that transmitted data can be effectively recovered at a receiving end. ## Claims ### Claim 1 A signal transmission method comprising: obtaining, by a sending end, information about a power fading point of a fiber channel between the sending end and a receiving end, wherein the obtaining, by a sending end, information about a power fading point of a fiber channel between the sending end and a receiving end comprises: obtaining, by the sending end, a frequency domain response of the fiber channel between the sending end and the receiving end, and determining, by the sending end, the power fading point of the fiber channel according to the frequency domain response; determining, by the sending end and according to the information about the power fading point, a subcarrier that is used to send a service signal to the receiving end on the fiber channel, wherein a frequency of the determined subcarrier is different from that of the power fading point; and sending, by the sending end, a service signal to the receiving end by using the determined subcarrier. ### Claim 2 (depends on 1) The method according to claim 1, wherein the obtaining, by the sending end, a frequency domain response of the fiber channel between the sending end and the receiving end specifically comprises: obtaining, by the sending end, a frequency domain response of each of the fiber channel with multiple kinds of transmission distances. ### Claim 3 (depends on 2) The method according to claim 2, wherein the determining, by the sending end, the power fading point of the fiber channel according to the frequency domain response specifically comprises: determining, by the sending end, a power fading point of each of the fiber channel with a corresponding transmission distance according to a frequency domain response of the fiber channel with the corresponding transmission distance. ### Claim 4 (depends on 1) The method according to claim 1, wherein after the determining a subcarrier that is used to send a service signal to the receiving end on the fiber channel, the method further comprises: sending, by the sending end, a test signal on determined subcarriers by using at least two kinds of modulation schemes; and determining, by the sending end and in the determined subcarriers, a subcarrier applicable to each kind of modulation scheme according to a performance indicator, of the test signal, that is corresponding to its respective modulation scheme at the receiving end. ### Claim 5 A transmitter comprising: a processor; a memory storing program instructions to be executed in the processor, the program instructions comprising instructions that cause the processor to: obtain a frequency domain response of a fiber channel between the transmitter and a receiving end, determine a power fading point of a fiber channel according to the frequency domain response, obtain information about the power fading point of the fiber channel between the transmitter and the receiving end, and determine, according to the information about the power fading point, a subcarrier that is used to send a service signal to the receiving end on the fiber channel, wherein a frequency of the determined subcarrier is different from that of the power fading point; and a sender configured to send a service signal to the receiving end by using the determined subcarrier. ### Claim 6 (depends on 5) The transmitter according to claim 5, wherein the sender is further configured to send a test signal on determined subcarriers by using at least two kinds of modulation schemes, and wherein the processor is configured to determine, in the determined subcarriers, a subcarrier applicable to each kind of modulation scheme according to a performance indicator, of the test signal, that is corresponding to its respective modulation scheme at the receiving end. ### Claim 7 (depends on 5) The transmitter according to claim 5, wherein the program instructions comprise further instructions that cause the processor to obtain the power fading point of the fiber channel according to the frequency domain response comprises determining a power fading point of the fiber channel with a corresponding transmission distance according to the frequency domain response of the fiber channel with the corresponding transmission distance. ### Claim 8 (depends on 5) The transmitter according to claim 5, wherein the frequency domain response of the fiber channel comprises a frequency domain response of each of the fiber channel with multiple kinds of transmission distances. ### Claim 9 A signal transmission system comprising a transmitter and a receiver, wherein the transmitter comprises: a processor a processor; a memory storing program instructions to be executed in the processor, the program instructions comprising instructions that cause the processor to: obtain a frequency domain response of a fiber channel between the transmitter and a receiving end, determine a power fading point of the fiber channel according to the frequency domain response obtain information about the power fading point of the fiber channel between the transmitter and the receiving end, and determine, according to the information about the power fading point, a subcarrier that is used to send a service signal to the receiving end on the fiber channel, wherein a frequency of the determined subcarrier is different from that of the power fading point; and a sender configured to send a service signal to the receiving end by using the determined subcarrier. ### Claim 10 (depends on 9) The signal transmission system according to claim 9, wherein the sender is further configured to send a test signal on determined subcarriers by using at least two kinds of modulation schemes, and wherein the processor is configured to determine, in the determined subcarriers, a subcarrier applicable to each kind of modulation scheme according to a performance indicator, of the test signal, that is corresponding to its respective modulation scheme at the receiving end. ### Claim 11 (depends on 9) The signal transmission system according to claim 9, wherein the program instructions further comprise instructions that cause the processor to determine the power fading point of the fiber channel according to the frequency domain by determining a power fading point of the fiber channel with a corresponding transmission distance according to a frequency domain response of the fiber channel with the corresponding transmission distance. ### Claim 12 (depends on 9) The signal transmission system according to claim 9, wherein the frequency domain response of the fiber channel comprises a frequency domain response of each of the fiber channel with multiple kinds of transmission distances.