# US 10,389,447 B1 · Dimensional transformation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,389,447 B1 - Document ID: US10389447B1 - Status: Granted - Kind: B1 - Application number: 16/003,736 - Filed: 2018-06-08 - Granted: 2019-08-20 - Earliest claimed: 2018-06-08 - Assignees: Ciena Corporation - Applicants: Amir Khandani; Shahab Oveis Gharan; Michael Andrew Reimer; Maurice O'Sullivan; Kim B. Roberts - Inventors: Amir Khandani; Shahab Oveis Gharan; Michael Andrew Reimer; Maurice O'Sullivan; Kim B. Roberts - Web page: https://patentgrep.com/patent/US10389447B1 ## CPC - H04B 10/2543: due to fibre non-linearities, e.g. Kerr effect - H04B 10/516: Details of coding or modulation - H04B 10/541: {Digital intensity or amplitude modulation} - H04B 10/614: {comprising one or more polarization beam splitters, e.g. polarization multiplexed [PolMux] X-PSK coherent receivers, polarization diversity heterodyne coherent receivers (H04J14/06 takes precedence)} - H04B 10/6165: {Estimation of the phase of the received optical signal, phase error estimation or phase error correction} - H04J 14/06: Polarisation multiplex systems - H04L 25/03006: {Arrangements for removing intersymbol interference} - H04B 10/40: Transceivers - H04B 10/50: Transmitters - H04B 10/60: Receivers - H04L 1/0041: {Arrangements at the transmitter end} - H04L 1/203: {Details of error rate determination, e.g. BER, FER or WER} - H04L 2025/03636: {Algorithms using least mean square [LMS]} - H04B: TRANSMISSION - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A receiver may receive an optical signal over an optical communications channel established between the receiver and a transmitter, the received optical signal comprising a degraded version of a modulated optical signal generated at the transmitter. The receiver may determine received digital signals corresponding to a plurality of first dimensions of the received optical signal, wherein the first dimensions correspond to dimensions of an optical carrier modulated at the transmitter to represent a multi-bit symbol, and wherein the first dimensions are distributed over two or more timeslots. The receiver may determine preliminary digital drive signal estimates using an inverse dimensional transformation and the received digital signals, the preliminary digital drive signal estimates corresponding to a plurality of second dimensions. The receiver may determine an estimate of the multi-bit symbol using the preliminary digital drive signal estimates. The inverse dimensional transformation may average signal degradations in the received digital signals. ## Claims ### Claim 1 A method performed at an optical receiver comprising a polarizing beam splitter, an optical hybrid, photodetectors, analog-to-digital converters, and a processor, the method comprising: receiving an optical signal over an optical communications channel established between the optical receiver and an optical transmitter, wherein the received optical signal comprises a degraded version of a modulated optical signal generated at the optical transmitter; the polarizing beam splitter splitting the received optical signal into polarized components; the optical hybrid processing the polarized components to generate processed components; the photodetectors converting the processed components into received analog signals; the analog-to-digital converters converting the received analog signals into received digital signals corresponding to a plurality of first dimensions of the received optical signal, wherein the first dimensions correspond to dimensions of an optical carrier modulated at the optical transmitter to represent a multi-bit symbol, and wherein the first dimensions are distributed over two or more timeslots; the processor applying an inverse dimensional transformation to the received digital signals to generate preliminary digital drive signal estimates corresponding to a plurality of second dimensions; and the processor processing the preliminary digital drive signal estimates to generate an estimate of the multi-bit symbol. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein the plurality of second dimensions is less than the plurality of first dimensions. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein the two or more timeslots are non-consecutive. ### Claim 4 (depends on 1) The method as claimed in claim 1, wherein the first dimensions are distributed over two polarizations. ### Claim 5 (depends on 1) The method as claimed in claim 1, wherein the first dimensions are distributed over in-phase (I) and quadrature (Q) components of at least one polarization. ### Claim 6 (depends on 1) The method as claimed in claim 1, wherein the inverse dimensional transformation averages signal degradations in the received digital signals, the signal degradations caused by one or more of noise, nonlinear effects, polarization dependent loss or gain (PDL), and analog imperfections. ### Claim 7 (depends on 1) The method as claimed in claim 1, wherein the inverse dimensional transformation comprises a matrix, and wherein the matrix is substantially linear and substantially unitary. ### Claim 8 (depends on 1) The method as claimed in claim 1, wherein the first dimensions of the optical carrier are modulated at the optical transmitter based on transformed digital drive signals, the transformed digital drive signals having been determined at the optical transmitter using a dimensional transformation and preliminary digital drive signals. ### Claim 9 (depends on 8) The method as claimed in claim 8, wherein the dimensional transformation comprises a first matrix, wherein the inverse dimensional transformation comprises a second matrix, wherein the first and second matrices are substantially linear and substantially unitary, and wherein the second matrix is substantially the inverse of the first matrix. ### Claim 10 (depends on 1) The method as claimed in claim 1, the method comprising processing the received optical signal using an adaptive equalization circuit to compensate for linear impairments in the optical communications channel. ### Claim 11 An optical receiver configured to receive an optical signal over an optical communications channel established between the optical receiver and an optical transmitter, wherein the received optical signal comprises a degraded version of a modulated optical signal generated at the optical transmitter, the optical receiver comprising: a polarizing beam splitter configured to split the received optical signal into polarized components; an optical hybrid configured to process the polarized components to generate processed components; photodetectors configured to convert the processed components into received analog signals; analog-to-digital converters configured to convert the received analog signals into received digital signals corresponding to a plurality of first dimensions of the received optical signal, wherein the first dimensions correspond to dimensions of an optical carrier modulated at the optical transmitter to represent a multi-bit symbol, and wherein the first dimensions are distributed over two or more timeslots; a processor; and a memory storing computer-executable instructions which, when executed by the processor, cause the processor to apply an inverse dimensional transformation to the received digital signals to generate preliminary digital drive signal estimates corresponding to a plurality of second dimensions, and to process the preliminary digital drive signal estimate to generate an estimate of the multi-bit symbol. ### Claim 12 (depends on 11) The optical receiver as claimed in claim 11, wherein the plurality of second dimensions is less than the plurality of first dimensions. ### Claim 13 (depends on 11) The optical receiver as claimed in claim 11, wherein the two or more timeslots are non-consecutive. ### Claim 14 (depends on 11) The optical receiver as claimed in claim 11, wherein the first dimensions are distributed over two polarizations. ### Claim 15 (depends on 11) The optical receiver as claimed in claim 11, wherein the first dimensions are distributed over in-phase (I) and quadrature (Q) components of at least one polarization. ### Claim 16 (depends on 11) The optical receiver as claimed in claim 11, wherein the inverse dimensional transformation averages signal degradations in the received digital signals, the signal degradations caused by one or more of noise, nonlinear effects, polarization dependent loss or gain (PDL), and analog imperfections. ### Claim 17 (depends on 11) The optical receiver as claimed in claim 11, wherein the inverse dimensional transformation comprises a matrix, and wherein the matrix is substantially linear and substantially unitary. ### Claim 18 (depends on 11) The optical receiver as claimed in claim 11, wherein the first dimensions of the optical carrier are modulated at the optical transmitter based on transformed digital drive signals, the transformed digital drive signals having been determined at the optical transmitter using a dimensional transformation and preliminary digital drive signals. ### Claim 19 (depends on 18) The optical receiver as claimed in claim 18, wherein the dimensional transformation comprises a first matrix, wherein the inverse dimensional transformation comprises a second matrix, wherein the first and second matrices are substantially linear and substantially unitary, and wherein the second matrix is substantially the inverse of the first matrix. ### Claim 20 (depends on 11) The optical receiver as claimed in claim 11, wherein execution of the computer-executable instructions cause the optical receiver to process the received optical signal using an adaptive equalization circuit to compensate for linear impairments in the optical communications channel.