摘要:
Methods and systems for soft-decision non-binary low-density parity-check (LDPC) coding for ultra-long-haul optical transoceanic transmissions are provided. A receiver includes one or more maximum a posteriori (MAP) equalizers configured to decode one or more symbols of an encoded input stream to provide one or more symbol log-likelihood ratios (LLRs). One or more LLR estimators are configured to estimate the log-likelihood ratios of the one or more symbol LLRs to provide one or more bit LLRs. One or more non-binary LDPC decoders are configured to decode the input stream using the one or more bit LLRs to recover an original input stream.
摘要:
An inventive method for multi-symbol polarization switching for differential detection optical systems includes modulating a laser source by a DQPSK modulator, driving the DQPSK modulator with a data block configured for generating multi-symbol polarization-switched DQPSK differential-encoded signals, and polarizing the multi-symbol polarization-switched DQPSK signals with a polarizing modulator whose modulation speed is based on how often polarization states vary, wherein the data block provides a bits manipulation to provide the multi-symbol polarization switching thereby enabling differential detection for recovering correct original data by a receiver.
摘要:
A method for optical chirp-free optical polarization modulation includes dividing a data modulated optical signal into a first optical path and a second optical path, using a Mach-Zehnder intensity modulator in the first optical path for imparting a π phase difference between adjacent symbols of the data modulated optical signal in the first optical path, adjusting a delay and amplitude of symbols of the data modulated optical signal in the second path so that the symbols in the first path and the symbols in the second path are synchronized and have substantially equal power levels, and combining the first and second optical paths so that symbols from the first and second optical paths are in orthogonal polarizations.
摘要:
An inventive method for coherent interleaved polarization-multiplexing PolMux optical communications with a single IQ modulator includes modulating a light source to generate a 50% return-to-zero RZ signal pulse at a frequency Rs, driving a single IQ modulator with inphase I and quadrature phase Q data at a bit rate of sais Rs to introduce phase modulation on said 50% RZ signal pulse to produce a QPSK pulse signal with all symbols being in a same polarization state without any time overlapping; and polarization modulating said QPSK signal to alternatively convert said QPSK signal into two orthogonal polarizations states enabling an interleaving PolMux signal with a symbol rate of Rs/2.
摘要:
An inventive method for multi-symbol polarization switching for differential detection optical systems includes modulating a laser source by a DQPSK modulator, driving the DQPSK modulator with a data block configured for generating multi-symbol polarization-switched DQPSK differential-encoded signals, and polarizing the multi-symbol polarization-switched DQPSK signals with a polarizing modulator whose modulation speed is based on how often polarization states vary, wherein the data block provides a bits manipulation to provide the multi-symbol polarization switching thereby enabling differential detection for recovering correct original data by a receiver.
摘要:
An optical method for generating an optical quadrature duobinary QDB signal includes receiving a quadrature phase-shift-keying QPSK signal, and adding a delay to the received quadrature phase-shift-keying QPSK signal to generate an optical quadrature duobinary signal.
摘要:
A method for optical chirp-free optical polarization modulation includes dividing a data modulated optical signal into a first optical path and a second optical path, using a Mach-Zehnder intensity modulator in the first optical path for imparting a π phase difference between adjacent symbols of the data modulated optical signal in the first optical path, adjusting a delay and amplitude of symbols of the data modulated optical signal in the second path so that the symbols in the first path and the symbols in the second path are synchronized and have substantially equal power levels, and combining the first and second optical paths so that symbols from the first and second optical paths are in orthogonal polarizations.
摘要:
Methods and systems for transmitting and receiving data include reverse concatenated encoding and decoding. Reverse concatenated decoding includes inner decoding the encoded stream with an inner decoder that uses a low-complexity linear-block code to produce an inner-decoder output stream, outer decoding the inner-decoder output stream with an outer decoder that uses a low-density parity-check code to produce an information stream, and iterating extrinsic bit reliabilities from the outer decoding for use in subsequent inner decoding to improve decoding performance.
摘要:
Methods and systems for reduced-complexity decoding of low-density parity-check (LDPC) information. An encoded input stream is received. The received stream is decoded with one or more reduced-complexity min-sum or a posteriori probability LDPC decoders. A v-node update rule in the reduced complexity decoder is omitted.
摘要:
A method of encoding for optical transmission of information includes encoding information with a generalized low-density parity-check (GLDPC) code for providing coding gains, and constructing the GLDPC code with a Reed-Muller RM code as a component code, the component code being decodable using a maximum posterior probability (MAP) decoding. In a preferred embodiment, the GLDPC code includes a codeword length of substantially 4096, an information word length of substantially 3201, a lower-bound on minimum distance of substantially greater than or equal to 16, a code rate of substantially 0.78 and the RM component code includes an order of substantially 4 and an r parameter of substantially 6.