# US 10,484,131 B2 · Communications with conditional chain decoding > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,484,131 B2 - Document ID: US10484131B2 - Status: Granted - Kind: B2 - Application number: 15/841,988 - Filed: 2017-12-14 - Published: 2019-06-20 - Granted: 2019-11-19 - Earliest claimed: 2017-12-14 - Assignees: Ciena Corporation - Applicants: Shahab Oveis Gharan; Mohammad Ehsan Seifi; Masoud Ebrahimi Tazeh Mahalleh; Kim B. Roberts - Inventors: Shahab Oveis Gharan; Mohammad Ehsan Seifi; Masoud Ebrahimi Tazeh Mahalleh; Kim B. Roberts - Web page: https://patentgrep.com/patent/US10484131B2 ## CPC - H04L 1/0042: {Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape (H04L1/0067 takes precedence)} - H04L 1/0041: {Arrangements at the transmitter end} - H04L 1/0048: {in conjunction with detection of multiuser or interfering signals, e.g. iteration between CDMA or MIMO detector and FEC decoder (for spatial equalizer H04L25/03286)} - H04L 1/0057: {Block codes (H04L1/0061, H04L1/0064 take precedence)} - H04L 1/0058: {Block-coded modulation} - H04L 27/362: {Modulation using more than one carrier, e.g. with quadrature carriers, separately amplitude modulated (H04L27/366 takes precedence)} - H04L 2027/0057: {quadrature phase} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Client data bits, including first client data bits and second client data bits, are communicated from a transmitter to a receiver. At the transmitter, the first client data bits are processed to generate processed values, where each processed value is more likely to be a first element than a second element. Forward Error Correction ‘FEC’ encoding is applied to the second client data bits to generate FEC-encoded values. Symbols are created by mapping the FEC-encoded values to first positions in the symbols and by mapping the processed values to second positions in the symbols. The symbols are modulated onto a communications channel using a modulation scheme with a code that assigns a lower average energy to symbols containing the first elements in the second positions than to symbols containing the second elements in the second positions. At the receiver, client data bits are decoded using conditional chain decoding. ## Claims ### Claim 1 A method performed at a transmitter for communicating client data bits over a communications channel to a receiver, the client data bits comprising first client data bits and second client data bits, each first client data bit and each second client data bit having a substantially equal probability of being zero and being one, the method comprising: processing the first client data bits to generate processed values, wherein each processed value has a substantially higher probability of being one or more first elements than of being one or more second elements; applying first forward error correction ‘FEC’ encoding to the processed values to generate first FEC-encoded values consisting of FEC-encoded processed values and redundant values; applying second FEC encoding to at least the second client data bits to generate second FEC-encoded values; creating symbols by mapping the second FEC-encoded values to one or more first positions in the symbols and by mapping the FEC-encoded processed values to one or more second positions in the symbols; and modulating the symbols onto the communications channel using a modulation scheme with a code that assigns a lower average energy to symbols containing the one or more first elements in the one or more second positions than to symbols containing the one or more second elements in the one or more second positions. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein the second FEC encoding is applied to the second client data bits and to the redundant values to generate the second FEC-encoded values. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein an information rate of the first FEC encoding is higher than an information rate of the second FEC encoding. ### Claim 4 (depends on 1) The method as claimed in claim 1, wherein the first FEC encoding comprises systematic FEC encoding. ### Claim 5 (depends on 1) The method as claimed in claim 1, wherein the code comprises one or more of a non-Gray code and a contrast code. ### Claim 6 (depends on 5) The method as claimed in claim 5, wherein the non-Gray code comprises a natural code. ### Claim 7 (depends on 1) The method as claimed in claim 1, wherein the modulation scheme comprises one of a pulse-amplitude modulation ‘FAM’ modulation scheme and a quadrature-amplitude modulation ‘QAM’ modulation scheme. ### Claim 8 (depends on 1) The method as claimed in claim 1, wherein the processing is performed using a tree code. ### Claim 9 (depends on 1) The method as claimed in claim 1, wherein the processed values, the first-FEC-encoded values, and the second FEC-encoded values are bits. ### Claim 10 A method performed at a receiver for decoding client data bits from a signal received over a communications channel from a transmitter, the client data bits comprising first client data bits and second client data bits, each first client data bit and each second client data bit having a substantially equal probability of being zero and being one, the method comprising: determining estimates of transmitted symbols from the signal received over the communications channel based on a modulation scheme implemented at the transmitter; determining, from the estimates of the transmitted symbols, first value estimates for one or more first positions in the transmitted symbols based on a code implemented at the transmitter; determining, from the estimates of the transmitted symbols, two or more conditional second value estimates for one or more second positions in the transmitted symbols, wherein each conditional second value estimate corresponds to a different value or combination of values in the one or more first position; applying second forward error correction ‘FEC’ decoding to the first value estimates to generate corrected first values, wherein the corrected first values consist of the second client data bits and redundant values; using the corrected first values to select second value estimates from the conditional second value estimates; applying first FEC decoding to at least the selected second value estimates to generate corrected second values, wherein each corrected second value has a substantially higher probability of being one or more first elements than of being one or more second elements; and processing the corrected second values to generate the first client data bits. ### Claim 11 (depends on 10) The method as claimed in claim 10, wherein the first FEC decoding is applied to the second value estimates and to the redundant values to generate the second corrected values. ### Claim 12 (depends on 10) The method as claimed in claim 10, wherein the code assigns a lower average energy to symbols containing the one or more first elements in the one or more second positions than to symbols containing the one or more second elements in the one or more second positions. ### Claim 13 (depends on 10) The method as claimed in claim 10, wherein the code comprises one or more of a non-Gray code and a contrast code. ### Claim 14 (depends on 10) The method as claimed in claim 10, wherein the modulation scheme comprises one of a pulse-amplitude modulation ‘FAM’ modulation scheme and a quadrature-amplitude modulation ‘QAM’ modulation scheme. ### Claim 15 (depends on 10) The method as claimed in claim 10, wherein the corrected first values and the corrected second values are bits. ### Claim 16 A receiver electronic device configured for decoding client data bits from a signal received over a communications channel from a transmitter electronic device, the client data bits comprising first client data bits and second client data bits, each first client data bit and each second client data bit having a substantially equal probability of being zero and being one, the receiver electronic device comprising: a processor; and a memory storing computer-executable code which, when executed by the processor, causes the receiver electronic device to determine estimates of transmitted symbols from the signal received over the communications channel based on a modulation scheme implemented at the transmitter; to determine, from the estimates of the transmitted symbols, first value estimates for one or more first positions in the transmitted symbols based on a code implemented at the transmitter; to determine, from the estimates of the transmitted symbols, two or more conditional second value estimates for one or more second positions in the transmitted symbols, wherein each conditional second value estimate corresponds to a different value or combination of values at the one or more first positions; to apply second forward error correction ‘FEC’ decoding to the first value estimates to generate corrected first values, wherein the corrected first values consist of the second client data bits and redundant values; to use the corrected first values to select second value estimates from the conditional second value estimates; to apply first FEC decoding to the selected second value estimates to generate corrected second values, wherein each corrected second value has a substantially higher probability of being one or more first elements than of being one or more second elements; and to process the corrected second values to generate the first client data bits. ### Claim 17 (depends on 16) The receiver electronic device as claimed in claim 16, wherein the first FEC decoding is applied to the second value estimates and to the redundant values to generate the second corrected values. ### Claim 18 (depends on 16) The receiver electronic device as claimed in claim 16, wherein the code assigns a lower average energy to symbols containing the one or more first elements in the one or more second positions than to symbols containing the one or more second elements in the one or more second positions. ### Claim 19 (depends on 16) The receiver electronic device as claimed in claim 16, wherein the code comprises one or more of a non-Gray code and a contrast code. ### Claim 20 (depends on 16) The receiver electronic device as claimed in claim 16, wherein the modulation scheme comprises one of a pulse-amplitude modulation ‘FAM’ modulation scheme and a quadrature-amplitude modulation ‘QAM’ modulation scheme. ### Claim 21 A transmitter electronic device configured for communicating client data bits over a communications channel to a receiver electronic device, the client data bits comprising first client data bits and second client data bits, each first client data bit and each second client data bit having a substantially equal probability of being zero and being one, the transmitter electronic device comprising: a processor; and a memory storing computer-executable code which, when executed by the processor, causes the transmitter electronic device to process the first client data bits to generate processed values, wherein each processed value has a substantially higher probability of being one or more first elements than of being one or more second elements; to apply first forward error correction TEC' encoding to the processed values to generate first FEC-encoded values consisting of FEC-encoded processed values and redundant values; to apply second FEC encoding to at least the second client data bits to generate second FEC-encoded values; to create symbols by mapping the second FEC-encoded values to one or more first positions in the symbols and by mapping the FEC-encoded processed values to one or more second positions in the symbols; and to modulate the symbols onto the communications channel using a modulation scheme with a code that assigns a lower average energy to symbols containing the one or more first elements in the one or more second positions than to symbols containing the one or more second elements in the one or more second positions. ### Claim 22 (depends on 21) The transmitter electronic device as claimed in claim 21, wherein the second FEC encoding is applied to the second client data bits and to the redundant values to generate the second FEC-encoded values. ### Claim 23 (depends on 21) The transmitter electronic device as claimed in claim 21, wherein an information rate of the first FEC encoding is higher than an information rate of the second FEC encoding. ### Claim 24 (depends on 21) The transmitter electronic device as claimed in claim 21, wherein the code comprises one or more of a non-Gray code and a contrast code.