Abstract: Methods, systems, and devices are described for formatting of data streams to be transmitted over fiber optic channels, and for processing received optical signals. A data transmission device may include a digital coding and modulation module that encodes a digital data stream, inserts unique words into the digital data stream, and modulates the encoded data stream and unique words onto optical channels for transmission over an optical fiber. A demodulation and decoding device may include a unique word identification module that identifies the unique words inserted in each optical channel stream, determines one or more characteristics of the plurality of optical channels based on the unique words, and provides the one or more characteristics to one or more other modules in the demodulator and decoding device.

Abstract: Methods, systems, and devices are described for a digital demodulator device for processing received optical signals. The device may include a quadrature error filter that receives a digitized version of an optical signal, and removes quadrature errors to generate a filtered series of data samples. The device may also include a frequency offset removal module for performing frequency rotation on the filtered series of data samples. The device may include a chromatic dispersion compensation module which removes chromatic dispersion from horizontal and vertical polarization channels. The device may include a polarization mode dispersion (PMD)/polarization dependent loss (PDL) compensation module which compensates for interference caused by PMD and PDL. The device may also include a phase recovery module configured to track and correct phase.

Abstract: Methods, systems, and devices are described for forward error correction for flash memory. Encoded data from flash memory may be used to generate a number of data streams. At each of a number of error detection sub-modules operating in parallel, a different one of the data streams is processed. Each error detection sub-module may detect whether a portion of the respective received stream contains an error, and forward the portion to an error correction module. The error correction module, physically separate from the error detection sub-modules, may correct the forwarded portions of the respective received streams containing an error. The age and error rate associated with the flash memory may be monitored, and a coding rate or other aspects may be dynamically adapted to account for these factors.

Abstract: A decoder may perform node data reordering for bit node processing and node data reordering for bit node to check node interconnections. The decoder may also utilize a single barrel shifting operation on data read from an edge memory for bit node processing or check node processing during a memory read operation. The decoder may also utilize a single format conversion on data read from an edge memory for bit node processing or check node processing. The decoder may also utilize a simplified check node process for check node processing.

Abstract: A method of turbo decoding using soft input-soft output information. A vector of data is sampled from a channel of data. The vector of data is then processed to output a final code word of bits. A final reliability vector of reliability values associated with the final code word is generated, such that each bit of the final code word of bits has a corresponding reliability value in the final reliability vector. Corresponding reliability values for one or more bit positions of the final code word are determined by a difference of distance metrics, and corresponding reliability values for one or more bit positions of the final code word are determined utilizing a numerical approximation.

Abstract: A decoder may perform node data reordering for bit node processing and node data reordering for bit node to check node interconnections. The decoder may also utilize a single barrel shifting operation on data read from an edge memory for bit node processing or check node processing during a memory read operation. The decoder may also utilize a single format conversion on data read from an edge memory for bit node processing or check node processing. The decoder may also utilize a simplified check node process for check node processing.

Abstract: A method of turbo decoding using soft input-soft output information. A vector of data is sampled from a channel of data. The vector of data is then processed to output a final code word of bits. A final reliability vector of reliability values associated with the final code word is generated, such that each bit of the final code word of bits has a corresponding reliability value in the final reliability vector. Corresponding reliability values for one or more bit positions of the final code word are determined by a difference of distance metrics, and corresponding reliability values for one or more bit positions of the final code word are determined utilizing a numerical approximation.