Abstract: A receiver includes a polar decoder for decoding an encoded codeword transmitted over a communication channel The receiver includes a front end to receive over a communication channel a codeword including a sequence of bits modified with noise of the communication channel and a soft decoder operated by a processor to produce a soft output of the decoding. The codeword is encoded by at least one polar encoder with a polar code. The processor is configured to estimate possible values of the bits of the received codeword using a successive cancelation list (SCL) decoding to produce a set of candidate codewords, determine a distance between each candidate codeword and a soft input to the soft decoder, and determine a likelihood of a value of a bit in the sequence of bits using a difference of distances of the candidate codewords closest to the received codeword and having opposite values at the position of the bit.

Abstract: A transmitter for transmitting an encoded codeword over a communication channel includes a source to accept source data, an irregular polar encoder operated by a processor to encode the source data with at least one polar code to produce the encoded codeword, a modulator to modulate the encoded codeword, and a front end to transmit the modulated and encoded codeword over the communication channel. The polar code is specified by a set of regular parameters including one or combination of parameters defining a number of data bits in the codeword, a parameter defining a data index set specifying locations of frozen bits in the encoded codeword, and a parameter defining a number of parity bits in the encoded codeword.

Abstract: When writing information to the IC tag of a medium, the control unit 54 of a printer 1 determines if a specific area in the storage space of the IC tag is in an initialized state, and writes to the IC tag if the IC tag is in the specific state.

Abstract: A transmitter includes a plurality of antennas for beamforming with different angles of departure (AoD), an information interface to receive a sequence of symbols including a first symbol and a second symbol and a modulator to cause the plurality of antennas to form a transmission beam with an AoD selected according to a value of the first symbol and modulated according to a value of the second symbol.

Abstract: The processor of a printer prints a setting value settable in a setting item of one in which a setting value is set on a print medium on the basis of input to an input section in a setting mode for setting a setting value in the setting item of one. If the first setting value of the setting item of one is stored in a memory, the processor causes a printing mechanism to print a first image in association with the setting value corresponding to the first setting value of the setting item of one out of the setting values to be printed. If the first setting value is not stored, the processor causes the printing mechanism to print the first image in association with the setting value corresponding to a second setting value of the setting item of one out of the setting values to be printed.

Abstract: A method decodes an optical signal transmitted over an optical channel from a transmitter to a receiver. The receiver receives the transmitted optical signal to produce a digital signal which is filtered in the frequency domain for compensating static effects and/or dynamic effects. The filtering is performed in the frequency domain, while the frequency coefficients of the filter are updated in the time domain by updating at least some of time coefficients of the filter and transforming the time coefficients into the frequency domain.

Abstract: Methods and systems for decoding symbols transmitted over an optical channel having a cross-polarization modulation (XPolM) impairment, wherein an optical signal is polarized to encode the symbols on an x-polarization and an y-polarization before transmitted. The method including receiving the optical signal transmitted over the optical channel. Sampling the optical signal to produce a sequence of digital samples, wherein each digital sample includes a measurement of each polarization of the optical signal at an instance of time. Selecting a subset of the sequence of digital samples that includes a digital sample and neighboring digital samples on the sequence. Repeating the selecting and the determining for each digital sample remaining in the sequence of digital samples to produce a sequence of cross-talk coefficients; and decoding some of the symbols from the sequence of digital samples using cross-talk models with corresponding cross-talk coefficients, wherein method steps are performed using a processor.

Abstract: Methods and systems for decoding symbols transmitted over an optical channel having a cross-polarization modulation (XPolM) impairment, wherein an optical signal is polarized to encode the symbols on an x-polarization and an y-polarization before transmitted. The method including receiving the optical signal transmitted over the optical channel. Sampling the optical signal to produce a sequence of digital samples, wherein each digital sample includes a measurement of each polarization of the optical signal at an instance of time. Selecting a subset of the sequence of digital samples that includes a digital sample and neighboring digital samples on the sequence. Repeating the selecting and the determining for each digital sample remaining in the sequence of digital samples to produce a sequence of cross-talk coefficients; and decoding some of the symbols from the sequence of digital samples using cross-talk models with corresponding cross-talk coefficients, wherein method steps are performed using a processor.

Abstract: An optical waveguide interferometer that includes a first optical section, a second optical section, and a set of optical waveguides configured to connect the first and second optical sections, such that light propagating between the first optical section and the second optical section passes through each optical waveguide in the set, wherein the set of optical waveguides includes a first optical waveguide having a first length and a first width and a second optical waveguide having a second length and a second width, wherein the second length is greater than the first length, and the second width is greater than the first width.

Abstract: To use resources effectively and run appropriate processes in a configuration having multiple communication interfaces, a print control processor 201 switches a target buffer for processing data between a first receive buffer 24 that stores data received from a POS terminal 10, and a second receive buffer 26 that stores data received from a tablet terminal 13. The print control processor 201 controls a print mechanism 21 based on data stored in the receive buffer that is currently selected as the target buffer, changes the target buffer selection from the first receive buffer 24 to the second receive buffer 26 when control of the print mechanism 21 based on receipt print data stored in the first receive buffer 24 goes to a specific control state, and resets the target buffer selection to the first receive buffer 24 when control of the print mechanism based on the data stored in the second receive buffer 26 ends.

Abstract: A method for decoding a codeword transmitted over a channel demodulates data received over the channel to produce an initial estimate of belief messages for bits of the codeword and decodes the codeword using a belief propagation (BP) decoding that iteratively passes the belief messages between a set of variable nodes representing the bits of the codeword and a set of check nodes representing parity-check constraints on the bits of the codeword until a termination condition is met. The BP decoding selects a look-up table based on a probability of the belief messages and maps, using the look-up table, values of at least two incoming belief messages to values of at least one outgoing belief message that forms an incoming belief message in a subsequent iteration of the BP decoding.

Abstract: An optical data coding method includes at least steps of selecting a modulation scheme comprising an X-polarization constellation format having first and second amplitude rings with circular grids corresponding to predetermined phase angles and a Y-polarization constellation format having the first and second amplitude rings with the circular grids corresponding to the predetermined phase angles, arranging a first part of the symbol on a first circular grid of the first amplitude ring on the X-polarization constellation format, and arranging a second part of the symbol on a second circular grid of the second amplitude ring on the Y-polarization constellation format.

Abstract: A method decodes an optical signal transmitted over an optical channel from a transmitter to a receiver. The receiver receives the transmitted optical signal to produce a digital signal which is filtered in the frequency domain for compensating static effects and/or dynamic effects. The filtering is performed in the frequency domain, while the frequency coefficients of the filter are updated in the time domain by updating at least some of time coefficients of the filter and transforming the time coefficients into the frequency domain.

Abstract: A power encoder includes a pulse width modulator for modulating a signal according to a set of thresholds to produce a pulse width modulated (PWM) signal and a switch mode power amplifier for amplifying the PWM signal by switching states of switching devices according to amplitudes of the PWM signal. At least one or combination of a distribution of values of the voltage thresholds in the set and a distribution of values of a current generated by different switching devices are non-uniform. The set of voltage thresholds includes at least two positive voltage thresholds.

Abstract: A method receives the symbol transmitted over a channel, selects, from a constellation of codewords, a first codeword neighboring the received symbol and a set of second codewords neighboring the first codeword, and determines a relative likelihood of each second codeword being the transmitted symbol with respect to a likelihood of the first codeword being the transmitted symbol. Next, the method determines an approximation of a log-likelihood ratio (LLR) of each data bit in the received symbol as a log of a ratio of a sum of the relative likelihoods of at least some of the second codewords having the same value of the data bit to a sum of the relative likelihoods of at least some of the second codewords having different value of the data bit and decodes the received symbol using the LLR of each data bit.

Abstract: In an advanced adaptive modulation and coding (AMC) scheme, the code rate and the parity-check matrix (PCM) for low-density parity-check (LDPC) codes are adapted according to modulation formats and variable-iteration receivers. The degree distribution for the PCM adaptation is designed by heuristic optimization to minimize the required SNR via an extrinsic information transfer (EXIT) trajectory analysis for finite-iteration decoding. The method uses dynamic window decoding by generating spatially coupled PCM for quasi-cyclic LDPC convolutional coding. The method also provides a way to jointly optimize labeling and decoding complexity for high-order and high-dimensional modulations.

Abstract: The data are communicated from a transmitter to a receiver in a wireless communications network. Data symbols are modulated using a coded modulation to produce modulated symbols and the modulated symbols are precoded using a precoder matrix to produce precoded symbols. The precoder matrix is formed using a rotation matrix including phase angles for at least some elements of the rotation matrix with values determined according to a parametric function of indices of the elements storing the phase angles. Next, the data packets are formed using the precoded symbols and the data packets are transmitted over the wireless network. Multi-stage parametric phase precoding provides full-diversity and full-rate transmissions by using fast-transformable unitary matrices and deterministic diagonal phase rotation, whose phase angles are pre-determined to minimize the union bound for time-selective and frequency-selective fading channels.

Abstract: A method for decoding a codeword transmitted over a channel demodulates data received over the channel to produce an initial estimate of belief messages for bits of the codeword and decodes the codeword using a belief propagation (BP) decoding that iteratively passes the belief messages between a set of variable nodes representing the bits of the codeword and a set of check nodes representing parity-check constraints on the bits of the codeword until a termination condition is met. The BP decoding selects a look-up table based on a probability of the belief messages and maps, using the look-up table, values of at least two incoming belief messages to values of at least one outgoing belief message that forms an incoming belief message in a subsequent iteration of the BP decoding.

Abstract: A method receives the symbol transmitted over a channel, selects, from a constellation of codewords, a first codeword neighboring the received symbol and a set of second codewords neighboring the first codeword, and determines a relative likelihood of each second codeword being the transmitted symbol with respect to a likelihood of the first codeword being the transmitted symbol. Next, the method determines an approximation of a log-likelihood ratio (LLR) of each data bit in the received symbol as a log of a ratio of a sum of the relative likelihoods of at least some of the second codewords having the same value of the data bit to a sum of the relative likelihoods of at least some of the second codewords having different value of the data bit and decodes the received symbol using the LLR of each data bit.

Abstract: A method generates constant modulus multi-dimensional modulations for coherent optical communications by first projecting points in a constellation of the code onto a Poincare sphere or its higher-dimensional hyper-sphere. By using meta-heuristic procedures, nonlinear programming and gradient search methods, constellation points in the hyper-sphere are optimized in certain criteria, such as maximizing the minimum Euclidean distance, minimizing the union bound, minimizing the bit-error rate, minimizing the required signal-to-noise ratio, maximizing the nonlinear fiber reach, maximizing the phase noise tolerance, and maximizing the mutual information. Some methods use parametric unitary space-time block codes such as Grassmannian packing, and filter impulse response as well as unitary rotation over adjacent code blocks to generate near-constant modulus waveform, not only at the symbol timing, but also over the entire time.