# US 2017/0012666 A1 · Method for estimating a cyclostationary transmission channel, and corresponding receiver > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0012666 A1 - Document ID: US20170012666A1 - Status: Published application - Kind: A1 - Application number: 15/042,509 - Filed: 2016-02-12 - Published: 2017-01-12 - Earliest claimed: 2015-07-09 - Assignees: STMicroelectronics (Rousset) SAS - Applicants: Stmicroelectronics (Rousset) SAS - Inventors: Pierre Demaj; Yoann Bouvet - Web page: https://patentgrep.com/patent/US20170012666A1 ## CPC - H04B 3/54: Systems for transmission via power distribution lines - H04L 1/0041: {Arrangements at the transmitter end} - H04L 1/0045: {Arrangements at the receiver end} - H04L 1/0059: {Convolutional codes} - H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT} - H04L 5/0044: {Allocation of payload; Allocation of data channels, e.g. PDSCH or PUSCH} - H04L 27/2601: {Multicarrier modulation systems} - H04L 27/2647: {Arrangements specific to the receiver only (equalisation H04L27/01)} - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method is for processing an analog channel signal from a transmission channel. The analog channel signal conveys frames, the transmission channel being linear and cyclostationary for a duration of a frame. The method may include converting of the analog channel signal into a digital channel signal, and performing channel estimations for the frame based upon the digital channel signal to generate a sequence of N transfer functions of the transmission channel. Each of the sequence of N transfer functions may be respectively associated with N successive time slices. The method may include decoding at least some symbols of the frame using, for each of the symbols, a transfer function associated with a successive time slice including a respective symbol. ## Claims ### Claim at position 1 1-28. (canceled) ### Claim 29 A method for processing an analog channel signal from a transmission channel, the analog channel signal conveying a plurality of frames, the transmission channel being linear and cyclostationary for a duration of at least one frame, the method comprising: converting of the analog channel signal into a digital channel signal; performing a plurality of channel estimations for the at least one frame based upon the digital channel signal to generate a sequence of N transfer functions of the transmission channel; each of the sequence of N transfer functions being respectively associated with N successive time slices; a duration of the N successive time slices being equal to or less than a cyclostationary period of the transmission channel; and decoding at least some symbols of the at least one frame using, for each of the at least some symbols, a transfer function associated with a successive time slice including a respective symbol. ### Claim 30 (depends on 29) The method according to claim 29 wherein the generation of the sequence of N transfer functions comprises generating an initial sequence of M base transfer functions respectively associated with M successive reference symbols of the at least one frame, the M successive reference symbols temporally covering a period equal to or greater than the cyclostationary period, the sequence of N transfer functions being derived from the initial sequence of M base transfer functions. ### Claim 31 (depends on 30) The method according to claim 30 wherein the analog channel signal is from a digital-analog conversion of an initial digital signal; and wherein when a sampling frequency of the digital channel signal is different from a sampling frequency of the initial digital signal, the plurality of channel estimations comprises: estimating the initial sequence of M base transfer functions respectively performed based upon the M successive reference symbols of the at least one frame; and correcting the initial sequence of M base transfer functions with a phase shift corresponding to a shift of sampling frequency to generate the initial sequence of M base transfer functions. ### Claim 32 (depends on 30) The method according to claim 30 wherein the sequence of N transfer functions comprises averages of successive groups of at least some of the initial sequence of M base transfer functions. ### Claim 33 (depends on 30) The method according to claim 30 wherein the M successive reference symbols of the at least one frame correspond to a plurality of known symbols of the at least one frame, the M successive reference symbols being decoded without knowing a transfer function of the transmission channel. ### Claim 34 (depends on 33) The method according to claim 33 wherein each channel estimation is based upon a received decodable symbol and comprises: decoding of the received decodable symbol; re-encoding of the received decodable symbol to generate a re-encoded symbol; and determining the transfer function of the transmission channel based upon the re-encoded symbol and the received decodable symbol. ### Claim 35 (depends on 29) The method according to claim 29 wherein the channel analog signal is modulated based upon an orthogonal frequency-division multiplexing (OFDM) modulation. ### Claim 36 (depends on 29) The method according to claim 29 wherein the transmission channel comprises an electrical power line, the channel analog signal being conveyed via power-line communication; and wherein the cyclostationary period of the transmission channel is half of a period of an alternating current flowing on the electrical power line. ### Claim 37 (depends on 35) The method according to claim 35 wherein the channel analog signal is based upon a power-line communication (PLC) PLC-G3 standard. ### Claim 38 (depends on 33) The method according to claim 33 wherein each frame comprises a preamble sequence, a header following the preamble sequence, and a payload following the header; and wherein the M successive reference symbols is in the header and the payload. ### Claim 39 (depends on 32) The method according to claim 32 wherein M is equal 15; wherein N is equal to 7; and wherein the sequence of N transfer functions is averages taken two by two of fourteen successive transfer functions of the initial sequence of M base transfer functions. ### Claim 40 (depends on 29) The method according to claim 29 wherein decoding of symbols following a last reference symbol uses, successively and cyclically, the sequence of N transfer functions. ### Claim 41 (depends on 40) The method according to claim 40 wherein when the duration of the N successive time slices is different from the cyclostationary period, the decoding of the symbols following the last reference symbol also periodically comprises a shift of transfer function in the successive and cyclical use of the sequence of N transfer functions. ### Claim 42 (depends on 29) The method according to claim 29 wherein the channel analog signal is conveyed via power-line communication, the cyclostationary period of the transmission channel being half of a period of an alternating current flowing on an electrical power line; wherein a reference signal is delivered at each zero crossing of the alternating current; and wherein a value of the cyclostationary period of the transmission channel is adjusted based upon an occurrence of the reference signal. ### Claim 43 A receiver comprising: an input stage to be coupled to a transmission channel and configured to receive an analog channel signal; a converter stage configured to convert the analog channel signal to a digital channel signal, the analog channel signal conveying a plurality of frames, the transmission channel being linear and cyclostationary for a duration of at least one frame; and a processor configured to perform a plurality of channel estimations for the at least one frame based upon the digital channel signal to generate a sequence of N transfer functions of the transmission channel, each of the sequence of N transfer functions being respectively associated with N successive time slices, a duration of the N successive time slices being equal to or less than a cyclostationary period of the transmission channel, and decode at least some symbols of the at least one frame using, for each of the at least some symbols, a transfer function associated with a successive time slice including a respective symbol. ### Claim 44 (depends on 43) The receiver according to claim 43 wherein said processor is configured to generate the sequence of N transfer functions comprising: generating an initial sequence of M base transfer functions respectively associated with M successive reference symbols of the at least one frame, the M successive reference symbols temporally covering a period equal to or greater than the cyclostationary period, the sequence of N transfer functions being derived from the initial sequence of M base transfer functions. ### Claim 45 (depends on 44) The receiver according to claim 44 wherein the analog channel signal is from a digital-analog conversion of an initial digital signal; and wherein when a sampling frequency of the digital channel signal is different from a sampling frequency of the initial digital signal, said processor is configured to perform the plurality of channel estimations comprising: estimating the initial sequence of M base transfer functions respectively performed based upon the M successive reference symbols of the at least one frame; and correcting the initial sequence of M base transfer functions with a phase shift corresponding to a shift of sampling frequency to generate the initial sequence of M base transfer functions. ### Claim 46 (depends on 44) The receiver according to claim 44 wherein said processor is configured to generate the sequence of N transfer functions comprising averaging successive groups of at least some of the initial sequence of M base transfer functions. ### Claim 47 (depends on 44) The receiver according to claim 44 wherein the M successive reference symbols of the at least one frame correspond to a plurality of known symbols of the at least one frame, the M successive reference symbols being decoded without knowing a transfer function of the transmission channel. ### Claim 48 (depends on 47) The receiver according to claim 47 wherein said processor is configured to perform each channel estimation is based upon a received decodable symbol and comprising: decoding of the received decodable symbol; re-encoding of the received decodable symbol to generate a re-encoded symbol; and determining a transfer function of the transmission channel based upon the re-encoded symbol and the received decodable symbol. ### Claim 49 (depends on 43) The receiver according to claim 43 wherein the channel analog signal is modulated based upon an orthogonal frequency-division multiplexing (OFDM) modulation. ### Claim 50 (depends on 43) The receiver according to claim 43 wherein the transmission channel comprises an electrical power line, the channel analog signal being conveyed via power-line communication; and wherein the cyclostationary period of the transmission channel is half of a period of an alternating current flowing on the electrical power line. ### Claim 51 (depends on 50) The receiver according to claim 50 wherein the channel analog signal is based upon a power-line communication (PLC) PLC-G3 standard. ### Claim 52 (depends on 47) The receiver according to claim 47 wherein each frame comprises a preamble sequence, a header following the preamble sequence, and a payload following the header; and wherein the M successive reference symbols is in the header and the payload. ### Claim 53 (depends on 46) The receiver according to claim 46 wherein M is equal 15; wherein N is equal to 7; and wherein said processor is configured to generate the sequence of N transfer functions as averages taken two by two of fourteen successive transfer functions of the initial sequence of M base transfer functions. ### Claim 54 (depends on 43) The receiver according to claim 43 wherein decoding of symbols following a last reference symbol uses, successively and cyclically, the sequence of N transfer functions. ### Claim 55 (depends on 54) The receiver according to claim 54 wherein when the duration of the N successive time slices is different from the cyclostationary period, said processor is configured to decode the symbols following the last reference symbol periodically comprising a shift of transfer function in the successive and cyclical use of the sequence of N transfer functions. ### Claim 56 (depends on 54) The receiver according to claim 54 wherein the channel analog signal is conveyed via power-line communication, the cyclostationary period of the transmission channel being half of a period of an alternating current flowing on an electrical power line; wherein said input stage is configured to generate a reference signal at each zero crossing of the alternating current; and wherein said processor is configured to adjust a value of the cyclostationary period of the transmission channel based upon an occurrence of the reference signal. ### Claim 57 An electronic device comprising: an input stage to be coupled to a transmission channel and configured to receive an analog channel signal; a converter stage configured to convert the analog channel signal to a digital channel signal, the analog channel signal conveying a plurality of frames; and a processor configured to perform a plurality of channel estimations for the at least one frame based upon the digital channel signal to generate a sequence of N transfer functions of the transmission channel, each of the sequence of N transfer functions being respectively associated with N successive time slices, a duration of the N successive time slices being equal to or less than a cyclostationary period of the transmission channel, and decode at least some symbols of the at least one frame using, for each of the at least some symbols, a transfer function associated with a successive time slice including a respective symbol. ### Claim 58 (depends on 57) The electronic device according to claim 57 wherein said processor is configured to generate the sequence of N transfer functions comprising: generating an initial sequence of M base transfer functions respectively associated with M successive reference symbols of the at least one frame, the M successive reference symbols temporally covering a period equal to or greater than the cyclostationary period, the sequence of N transfer functions being derived from the initial sequence of M base transfer functions. ### Claim 59 (depends on 58) The electronic device according to claim 58 wherein the analog channel signal is from a digital-analog conversion of an initial digital signal; and wherein when a sampling frequency of the digital channel signal is different from a sampling frequency of the initial digital signal, said processor is configured to perform the plurality of channel estimations comprising: estimating the initial sequence of M base transfer functions respectively performed based upon the M successive reference symbols of the at least one frame; and correcting the initial sequence of M base transfer functions with a phase shift corresponding to a shift of sampling frequency to generate the initial sequence of M base transfer functions. ### Claim 60 (depends on 58) The electronic device according to claim 58 wherein said processor is configured to generate the sequence of N transfer functions comprising averaging successive groups of at least some of the initial sequence of M base transfer functions.