Abstract: A fiber optic system includes a transmitter configured to utilize a plurality of modulation formats and a receiver communicatively coupled to the transmitter and configured to utilize a plurality of modulation formats. The transmitter and the receiver are cooperatively configured to set a modulation format of the plurality of modulation formats based upon optical signal-to-noise ratio associated therewith. A flexible bandwidth adaptation method includes monitoring at least one aspect of an optical link at a network element, responsive to the at least one aspect, computing a new modulation scheme for the optical link, and, if a solution is found for the new modulation scheme, changing to the new modulation format.

Abstract: A system and method including a parity bit encoder for encoding bits of data to be transmitted with first and second parity check bits to produce successive block of bits. Each of the blocks of bits are Gray mapped to a plurality of associated QAM symbols that are modulated onto an optical wavelength and transmitted to a receiver. A de-mapper corrects for 90 degree and 180 degree cycle slip using parity indicated by the first and second parity bits.

Abstract: An apparatus and a method for operating a transmission end in a wireless communication system that supports Frequency and Quadrature-Amplitude Modulation (FQAM) are provided. The method includes dividing an information bit stream into a plurality of portions, encoding each of the plurality of portions using different encoding schemes, and generating an FQAM symbol by combining result values of the encoding of each of the plurality of portions, wherein the encoding schemes are different according to at least one of an encoding order, an encoding rate, an input size, and an encoding technique.

Abstract: In a coherent receiver of an optical communication system, a method of processing a detected symbol estimate to determine a most likely value of a corresponding transmitted data word, the transmitted data word comprising one or more data bits encoded in a transmitter using a predetermined constellation of at least two symbols. A set of two or more virtual constellation points are define in a decision region corresponding to a possible value of the data word. The detected symbol estimate is processed to find a most likely virtual constellation point given the detected symbol estimate. The most likely value of the corresponding transmitted data word is determined based on the most likely virtual constellation point.

Abstract: A transmission module is provided that includes a transmitter, a loopback receiver, and a QEC controller. In a first state, the QEC controller calibrates the loopback receiver to remove quadrature imbalance in the loopback receiver. In a second state, a communication pathway is provided between the transmitter and the loopback receiver, and the QEC controller identifies quadrature imbalance in the transmitter based at least one a comparison of the data signals at the output of the loopback receiver with data signals at the input of the transmitter. Based on the comparison, the QEC controller can adjust one or more characteristics of the transmitter to correct quadrature errors in the transmitter.

Abstract: The present invention relates to method for communicating in a network, said network comprising a primary station and at least one secondary station having a plurality of antennas, the method comprising the step of the primary station transmitting to a first secondary station an indication of a first receive combining matrix that the first secondary station should use to combine the signals received at its said plurality of antennas from a first subsequent transmission from the primary station.

Abstract: A method of encoding data for transmission from a source to a destination over a communications channel is provided. The method operates on an ordered set of input symbols and includes generating a plurality of redundant symbols from the input symbols based on linear constraints. The method also includes generating a plurality of output symbols from a combined set of symbols including the input symbols and the redundant symbols based on linear combinations, wherein at least one of the linear constraints or combinations is over a first finite field and at least one other of the linear constraints or combinations is over a different second finite field, and such that the ordered set of input symbols can be regenerated to a desired degree of accuracy from any predetermined number of the output symbols.

Abstract: A method for decoding data symbols modulated with a corresponding codeword from a constellation set of codewords expands the constellation set of codewords with a set of basis functions to produce a basis-expanded constellation set and projects projecting a received modulated data symbol onto orthogonal complements of the basis expanded constellation set to obtain a set of distance metric of a generalized likelihood ratio test (GLRT) for each codeword of the constellation set. The set of basis functions includes a Fourier exponential basis function in a frequency domain, a Legendre polynomial basis function in a time domain, and a Fourier-Legendre product basis function in the frequency domain. The method selects a codeword corresponding to a minimal distance metric or a maximal correlation metric and decodes the data symbol from the received modulated data symbol using the codeword.

Abstract: The present invention discloses a transmitter, a receiver, and a method for receiving and transmitting a radio frequency signal, and relates to the field of radio communications technologies, which can perform carrier recovery and generation at a front end of a radio frequency circuit, thereby reducing a running cost of a baseband chip. The method includes: generating, by an amplitude discriminator/phase detector according to an intermediate-frequency analog signal, a signal amplitude pulse signal/signal phase pulse signal that is not corrected; generating, by a bit error matrix corrector, an amplitude/phase correction control signal; correcting, by the amplitude discriminator/phase detector, the signal amplitude pulse signal/signal phase pulse signal according to the amplitude/phase correction control signal; and converting, by an amplitude code generator/phase code generator, a corrected pulse signal into a corresponding digital code.

Abstract: An optical system may include an optical transmitter or an optical receiver. The optical transmitter may include a laser to provide an input signal, a first digital signal processor (DSP) to receive a data signal, provide non-rotated and rotated symbols corresponding to the data signal, and provide digital signals corresponding to the non-rotated and the rotated symbols to cause one or more digital to analog converts to convert the digital signals to analog signals. The optical transmitter may further provide a modified 5 quadrature amplitude modulation (5QAM) signal based on the analog signals and the input signal. A constellation map of the modified 5QAM signal may include all constellation points of a 16QAM signal. The optical receiver may include a second DSP to receive components associated with the 5QAM signal, filter the components, reduce phase noise of the 5QAM signal, and provide data associated with the 5QAM signal.

Abstract: A radio transmitting/receiving device uses a channel interleaver with turbo codes serving as error-correcting codes to convert burst errors into random errors. The radio transmitting/receiving device, in Code Block Concatenation (15), when dividing a Transport Block into a plurality of Code Blocks, performs channel coding so that burst errors that occur during transmission are distributed to all the Code Blocks. Therefore, when burst errors occur, the errors can be uniformly distributed to all Code Blocks in a Transport Block so that no unevenness occurs in error resilience between the Code Blocks.

Abstract: Wireless uplink communication is disclosed which includes dividing information bits into first and second sets of information bits. The first set of information bits is encoded into a first set of coded bits, while the second set of information bits is encoded into a second set of coded bits. The first and second sets of coded bits are rate matched into a defined number of bits generating first and second sets of rate-matched coded bits. The first and second sets of rate-matched coded bits are interleaved using various interleaving methods to generate an interleaved set of coded bits.

Abstract: A modulating device including: a first convertor configured to generate a converted analog signal by analog conversion on a input digital signal, a modulator configured to generate a modulated signal by quadrature modulation, a phase shifter configured to generate a phase shift signal by phase rotation, a demodulator configured to generate a demodulated signal by quadrature demodulation, a second convertor to generate a converted digital signal by digital conversion, a calculating circuit configured to estimate a the first direct current offset based on the input digital signal and the converted digital signal, the first direct current offset being a noise of digital current component generated between the input digital signal inputted to the first convertor and the output signal inputted to the demodulator, and a correcting circuit configured to correct at least one among from the input digital signal to the output signal based on the first direct current offset.

Abstract: A numerically controlled oscillator includes a phase accumulator configured to output a phase word, a clock configured to periodically output a clock signal in accordance with a delay interval, and a clock controller configured to adjust the delay interval. The phase accumulator is configured to output a new phase word in response to receiving the clock signal. An example method includes receiving a plurality of frequency control words, calculating a delay interval, accumulating the frequency control words in accordance with the delay interval to generate a phase word, and converting the phase word to a waveform.

Abstract: The present invention discloses a method for correcting an IQ signal. includes: saving an I signal of a last frame and a Q signal of the last frame that are output by a receiving front end; eliminating a direct-current offset of an I signal of a current frame and a direct-current offset of a Q signal of the current frame according to the I signal of the last frame and the Q signal of the last frame; and geometrically correcting an I signal of the current frame after direct-current offset elimination and a Q signal of the current frame after direct-current offset elimination according to an I signal of the last frame after direct-current offset elimination and a Q signal of the last frame after direct-current offset elimination to obtain a corrected I signal of the current frame and a corrected Q signal of the current frame.

Abstract: A system and method for communicating wirelessly from a mobile device to a remote receiver station is disclosed. The system includes a controller configured to monitor a status of the mobile device and, upon an initiation event, initiate a data transfer process to wirelessly communicate data to the remote receiver station. The system also includes a voice-band modem that, upon initiation of the data transfer process is configured to receive data for transfer to the remote receiver station, divide the source data into a collection source packets, and encode the data using a fountain code encoding protocol to form a series of encoded packets. The voice band modem is also configured to transmit the series of encoded packets to the remote receiver station as a burst including all of the source data and repeatedly transmit the encoded packets until receiving an indication that the series of packets including all of the source data has been received at the receiving station.

Abstract: An apparatus and method is disclosed with embodiments of a: 1. digital to analog and reference time converter; 2. analog and reference time to digital converter; 3. Sheahan non-linear time-varying, analog and digital control system; and 4. Sheahan Communication Channel are described in detail herein. Some embodiments use time stamp having 72 bits of time data sufficient to identify each clock pulse of a 9.192631770 GHz clock signal plus an additional 8 bits representing 28=256 interpolated clock phases in order reach a resolution of approximately 0.425 picoseconds per clock phase. Thus an 80 bit time stamp is generated and used as described herein.

Abstract: A phase excursion compensation circuit of a phase modulation signal demodulator detects occurrence of a slip of a received signal from a change in a phase compensation amount that is formed into the received signal by a phase excursion compensation unit, and corrects the phase compensation amount of the received signal after the slip is generated.

Abstract: Wireless communication wherein channel estimation accuracy is improved while keeping the position of each bit in a frame, even when a modulation system having a large modulation multiple value is used for a data symbol. An encoding operation encodes and outputs transmitting data (bit string) and a bit converting operation converts at least one bit of a plurality of bits constituting a data symbol to be used for channel estimation, among the encoded bit strings, into ‘1’ or ‘0’. A modulating operation modulates the bit string inputted from the bit converting operation by using a single modulation mapper and a plurality of data symbols are generated.

Abstract: Transmitter apparatus to broadcast coded orthogonal frequency-division multiplexed (COFDM) radio-frequency carriers conveying low-density parity-check (LPDC) coding transmits the same coded DTV signals twice some time apart. The coded DTV signals of initial transmissions and of final transmissions are mapped to quadrature amplitude modulation (QAM) of the COFDM carriers according to first and second patterns, respectively. Bits that map to lattice points in the first mapping pattern more likely to experience error are mapped to lattice points in the second mapping pattern less likely to experience error. Bits that map to lattice points in the second mapping pattern more likely to experience error are mapped to lattice points in the first mapping pattern less likely to experience error. Receiver apparatus combines the earlier and later transmissions of twice-transmitted COFDM signals as part of iterative procedures for de-mapping QAM and decoding the LDPC coding of the DTV signals.

Abstract: A method of transmitting a data signal using an optical transmitter of an optical communications system. The optical transmitter is configured to modulate an optical carrier in successive signalling intervals to generate an optical signal. A modulation scheme is provided which comprises a multi-dimensional symbol constellation. The modulation scheme is designed such that an average degree of polarization of a modulated optical signal output from the optical transmitter has a first value when averaged across a first signaling interval, and has a second value when averaged across more than one and fewer than 100 signaling intervals. The second value is less than 10 percent of the first value. During run-time, an encoder of the optical transmitter encoding a data signal to be transmitted as symbols of the constellation, and a modulator of the optical transmitter modulating available dimensions of the optical carrier in accordance with the symbols.

Abstract: The present technique relates to a data processing device and a data processing method that enable resistance to error of data to be improved. In the case in which an LDPC code having a code length of 16200 bits and an encoding rate of 8/15 is mapped to 16 signal points, if (#i+1)-th bits from most significant bits of sign bits of 4×2 bits and symbol bits of 4×2 bits of two consecutive symbols are set to bits b#i and y#i, respectively, a demultiplexer performs interchanging to allocate b0, b1, b2, b3, b4, b5, b6, and b7 to y0, y4, y3, y1, y2, y5, y6, and y7, respectively. The present technique can be applied to a transmission system or the like transmitting an LDPC code.

Abstract: Methods, systems, and apparatuses are described for compensating for impairments of a wireless device. In accordance with a disclosed method, a set of equalizer taps for an analog pipeline of the wireless device is determined. A first set of complex filter taps and a second set of complex filter taps are also determined, by modifying the set of equalizer taps according to an estimated imbalance of the analog pipeline of the wireless device. A signal associated with the analog pipeline is processed with a complex filter according to the first set of complex filter taps and the second set of complex filter taps. The processing provides a combined imbalance compensation and equalization of the signal. The complex filter may include a first complex half-filter associated with the first set of complex filter taps and a second complex half-filter associated with the second set of complex filter taps.

Abstract: Provided is a communication device which can handle variation in transmission power accompanying switching of a modulation system.

Abstract: A method may be provided to detect and correct data errors in a data system where a data message has been encoded with outer parity bits based on the data message using an outer encoding technique to provide an outer codeword and with inner parity bits based on the outer codeword using an inner encoding technique different than the outer encoding technique to provide an inner codeword. The method may include using the inner parity bits and an inner decoding technique corresponding to the inner encoding technique to perform inner decoding of the inner codeword. Responsive to performing inner decoding of the inner codeword without error, the data message may be extracted from a result of inner decoding the inner codeword without using the outer parity bits to decode the result of inner decoding the inner codeword. Related systems are also discussed.

Abstract: A unified frame structure for filter bank multi-carrier (FBMC) and orthogonal frequency division multiplexed (OFDM) waveforms may allow FBMC and OFDM frames to be communicated over a common channel without significant inter-frame gaps. The unified frame structure may set an FBMC frame duration to an integer multiple of an OFDM frame element duration to enable alignment of FBMC frames and OFDM frames in the time domain. The unified frame structure may also map control channels in the FBMC and OFDM frames to common resource locations so that the respective control channels are aligned in the time and/or frequency domains. The unified frame structure may also share synchronization channels between FBMC and OFDM frames. Additionally, overhead in an FBMC time division duplexed (TDD) communications channel can be reduced by overlapping time windows appended to FBMC blocks.

Abstract: Apparatuses and methods are provided for generating a plurality of redundancy versions using various rate matching algorithms. In some embodiments, a rate matcher is provided that allocates systematic and parity bits to the redundancy versions in a manner that allows all of these bits to be transmitted in at least one redundancy version. In some embodiments, the rate matcher uses a first puncturing algorithm to generate both a first redundancy version and a third redundancy version, but allocates a different proportion of the systematic bits to these redundancy versions. In these embodiments, the second redundancy version may include only bits that were not transmitted in the first redundancy version.

Abstract: Provided are a transmitter and a method for transmitting a data block in a wireless communication system. The method comprises the following steps: deciding the number of bits (s) and encoders (NES) to allocate to one axis of a signal constellation; encoding an information bit based on the s and the NES and generating a coded block; parsing the coded block based on the s and the NES and generating a plurality of frequency sub-blocks; and transmitting the plurality of frequency sub-blocks to a receiver.

Abstract: A method of transmitting control information from a wireless communication terminal to an access network includes generating control information comprising a plurality of control bits. The method also includes encoding the control bits using a block code that outputs an encoded bit sequence comprising encoded bits b(0), b(1), . . . , b(19) and dividing the encoded bits into a first group and a second group. The first group includes the encoded bits {b(0), b(1), b(2), b(3), b(4), b(6), b(7), b(8), b(13), b(19)} and the second group includes the encoded bits {b(5), b(9), b(10), 6(11), b(12), b(14), b(15), b(16), b(17), b(18)}. The method further includes transmitting the first group of encoded bits on a first set of carriers and transmitting the second group of encoded bits on a second set of carriers having different frequencies from the first set of carriers.

Abstract: An apparatus of transmitting data in a multi-carrier system includes: a plurality of pulse-shaping filters for performing pulse shaping of incoming data symbols during a set pulse-shaping period; and a plurality of frequency converters convert signals that are pulse-shaped by the plurality of pulse-shaping filters into signals with frequency bands for a plurality of subcarriers.

Abstract: The present invention is related to integrated multi-datastream transmission technology, more particularly, to integrated multi-datastream modulation technology. According to one aspect of the present invention, there is provided a modulation equipment (10), including: a symbol integration means (101), configured to combine a first bit stream with a second bit stream to form a symbol to be modulated; a symbol mapping means (102), configured to map the symbol to be modulated into a QAM modulation symbol according to a set of predetermined mapping rules; wherein, in the set of predetermined mapping rules, multiple constellations corresponding to any first bit stream are located in at least two quadrants in the constellation diagram, while multiple constellations corresponding to any second bit stream are located in at least two quadrants in the constellation diagram. The integrated transmission of a first service data and a second service data (e.g.

Abstract: A precoding codebook matrix/vector of length 2L is generated by the selection of two matrices/vectors, each from one of a predetermined set of L×L matrices and multiplying each column of one of the matrices/vectors by a complex coefficient.

Abstract: A receiving device including: a demodulation circuit configured to generate first likelihood data of reception symbols based on a transmission format of the reception symbols, the transmission format being selected from transmission formats and including a modulation scheme applied to the reception symbols, the modulation scheme being one of amplitude modulation schemes, a processor configured to estimate a scale ratio of an implementation scale to a theoretical scale, the implementation scale being a scale of the first likelihood data, the theoretical scale being a scale of second likelihood data of the reception symbols, the second likelihood data being defined by a theory and not depending on an implementation of the receiving device, and to generate the second likelihood data based on the first likelihood data and the scale ratio, and a decoding circuit configured to decode the second likelihood data based on the transmission format.

Abstract: A precoding method, a precoding apparatus, a Frequency Domain Equalization (FDE) method, and an FDE apparatus are provided in the embodiments of the present invention. The precoding method includes: performing offset modulation for a transmitting signal vector; calculating a precoding matrix according to the offset-modulated transmitting signal vector and a receiver decision signal vector, where the precoding matrix is used for performing precoding for the transmitting signal vector; and performing precoding for the transmitting signal vector according to the precoding matrix. Linear precoding is performed by using the offset-modulated signal on the transmitter, and therefore, the interference caused by multiple antennas and multipath propagation is reduced, the system BER is reduced, and the complexity of implementation is low.

Abstract: A system, method and node for modulation and coding scheme adjustment for a Long Term Evolution (LTE) shared Data Channel. The method determines an actual number of orthogonal frequency division multiplexing (OFDM) symbols, NOS utilized for the shared Data Channel. A modulation order for transmission of data on the shared Data Channel is increased when the actual number of OFDM symbols NOS is less than 11 and decreased when NOS is more than 11. A modulation and coding scheme field (IMCS) of a downlink control information of the shared Data Channel may also be determined. If 0?IMCS+11?NOS?28, the modulation order is modified by utilizing a factor of (IMCS+11?NOS) in a standardized modulation scheme. If it is determined that IMCS+11?NOS<0, the modulation order is set to Quadrature Phase Shift Keying (QPSK). If it is determined that IMCS+11?NOS>28, the modulation order is set to 64 Quadtrative Amplitude Modulation (64QAM).

Abstract: Disclosed is a method for generating and transmitting a reference signal in a clustered DFT-spread OFDM transmission scheme. A method for generating and transmitting a DM-RS in a clustered DFT-spread-OFDM scheme comprises: a step of generating DM-RS sequences corresponding to the number of clusters allocated for an uplink transmission; and a step of mapping the generated DM-RS sequences to the relevant DM-RS symbol positions for each cluster. Accordingly, the method for generating and transmitting a reference signal according to the present invention, in which DM-RS sequences are allocated and transmitted on a cluster basis, uses a complete DM-RS sequence for each cluster, and therefore inter-cell interference can be weakened, and problems which might occur when applied to a multi-user MIMO (MU-MIMO) scheme can be solved.

Abstract: A receiver front end circuit includes a low-noise amplifier including: a first receiver path having: a first low-noise transconductor to amplify a received signal and output the amplified received signal; and a first mixer to down-convert the amplified received signal. A second receiver path includes: an auxiliary receiver having: a second transconductor to output an amplified received signal; a baseband amplifier having an input port and an output port; a first resistance coupling the input port to the output port of the baseband amplifier and to convert the amplified received signal from current to voltage and set a voltage gain of the second receiver path; and a second resistance coupled from the output port of the baseband amplifier to the first mixer output. In some examples, frequency-upconversion feedback path includes a third mixer to frequency up-convert the amplified received signal at an output of the second receiver path.

Abstract: The present invention relates to clipping thresholds adjustment for Crest Factor Reduction CFR in a radio unit, wherein the radio unit comprises one or more clipping stages that apply respective clipping thresholds to clip input signals, comprising: determining a target threshold for the clipping stages based on a target PAR and the amplitudes or powers of the input signals, estimating the direction in which original PAR of the input signals changes by comparing amplitudes of the clipped signals from the clipping stages with the target threshold, and adjusting the clipping thresholds based on the estimated direction. The present invention also relates to dynamic stage control. With the present invention, clipping thresholds and clipping stages are adaptively changes with dynamic original PAR of input signals and the efficiency of power amplifier is increased with a low implementation cost.

Abstract: Methods and apparatus are provided for reducing Peak to Average Power Ratio (PAPR) in Orthogonal Frequency-Division Multiplexing (OFDM) modulation. A set of low complexity transformations is applied to an OFDM signal to generate a plurality of differently transformed OFDM signals. One of the plurality of differently transformed OFDM signals having a lowest PAPR is selected. The selected one of the plurality of differently transformed OFDM signals is transmitted.

Abstract: A method includes receiving signals transmitted over a communication channel in multiple blocks transmitted in respective frequency bins during respective time intervals. An estimate of the communication channel, for a given block transmitted during a respective time interval, is computed by (i) computing respective interim filtering results for the blocks transmitted in the respective time interval in the respective frequency bins belonging to the predefined subset, by filtering a first group of the reference signals that are transmitted in odd-order frequency bins and in a first set of symbols, so as to produce odd-order interim filtering results, and filtering a second group of the reference signals that are transmitted in even-order frequency bins and in a second set of symbols that does not overlap the first set, so as to produce even-order interim filtering results; and (ii) combining the odd-order interim filtering results and the even-order interim filtering results.

Abstract: Methods, apparatuses, and systems are provided for generating a candidate search set for ML detection of 2n-QAM signals transmitted on two or more MIMO spatial streams. A method includes estimating an initial solution yq for a received 2n-QAM symbol value b0b1 . . . bn-1, wherein all possible 2n-QAM symbol values are Gray-mapped constellation points; and performing an iteration for each hypothetical value of each bit position i of the initial solution yq, wherein each iteration comprises: determining a search center as: if ith bit of the initial solution equals the hypothetical value assumed for the current iteration, the initial solution yq; or if ith bit of the initial solution does not equal the hypothetical value assumed for the current iteration, a mirror constellation point yqc to the initial solution yq; and searching outward from the determined search center for candidate constellation points.

Abstract: Symbol detection and soft demapping methods and systems are provided. Individual subset symbol detection according to one or more embodiments involves identifying a search subset of a transmission symbol set for a transmission symbol. For each other transmission symbol in communication signals, multiple search subsets of the transmission symbol set are identified. The multiple search subsets include respective search subsets based on each transmission symbol in either the search subset for the first identified one of the transmission symbols or each of the multiple search subsets identified for a different one of the other transmission symbols. Symbol detection errors may be detected by identifying competing symbols and computing competing distances. Soft demapping may be provided by calculating soft decision results based on detected symbols and weighting the soft decision result.

Abstract: When a UE (12) is configured with MF-HSDPA and HARQ-ACK information associated with cells (14, 16) (characterized by potentially different downlink timing) is jointly encoded, only part of the existing Rel-9 HARQ-ACK codebook is reused. In one embodiment, only the codebook conflict arising from reuse of encodings is resolved. This is achieved by introducing a new codeword for at least one of the HARQ-ACK code words that are used multiple times in the existing Rel-9 codebook. In another embodiment, all codewords in the Rel-9 HARQ-ACK codebook having a Hamming distance smaller than a predetermined value (but not all codewords) are replaced. In yet another embodiment, all codewords in the Rel-9 HARQ-ACK codebook having a Hamming distance smaller than a predetermined value (but not all codewords) that would cause ambiguity at the NodeB receiver (i.e. where the interpretation of the HARQ-ACK information for one cell (14) depends on the number of streams transmitted at the other cell (16)) are replaced.

Abstract: A method for transmitting and receiving a signal and an apparatus for transmitting and receiving a signal are disclosed. The method includes receiving the signal from a first frequency band in a signal frame including at least one frequency band, demodulating the received signal by an orthogonal frequency division multiplexing (OFDM) method and parsing the signal frame, acquiring a symbol stream of a service stream from the at least one frequency band included in the parsed signal frame, demapping symbols included in the symbol stream and outputting the demapped symbols to sub streams, multiplexing the output sub streams and outputting one bit stream, and deinterleaving and error-correction-decoding the output bit stream.

Abstract: A method implemented in a multicarrier transmission system, the method comprising generating a plurality of constellation points by using one or more constellation mappers to map a plurality of special data sequences for an idle data transmission unit (IDTU), wherein the plurality of special data sequences are computed prior to the mapping such that the plurality of constellation points are essentially inner constellation points, wherein each of the inner constellation points resides in a constellation diagram that corresponds to one of a plurality of subcarriers used by the IDTU, and wherein the constellation diagram comprises a number of inner constellation points and a number of outer constellation points, with the inner constellation points being closer from an origin of the constellation diagram than the outer constellation points, and transmitting the plurality of constellation points.

Abstract: Described are systems and methods of estimating a Signal-to-Noise (S/N) ratio of an input channel carrying a QAM signal. A Modulation Error Ratio (MER) is calculated for the input QAM signal, but uses only the centermost error values of a constellation of the input QAM signal in generating this modified MER. The modified MER accurately represents the S/N ratio of the input channel carrying the QAM signal. In this way the S/N ratio may be accurately determined using only the received I and Q components of the modulated QAM input signal itself.

Abstract: A DMT system for a half-duplex two-way link carries Internet protocol encoded video stream on a coaxial cable that also carries a baseband rendition of the same video stream. A plurality of downlink symbols modulated on a subband of subcarriers in a downlink signal are decoded. The symbols may carry data encoded on a subband using a constellation of QAM symbols assigned to the subband. Other subbands may be associated with different QAM constellations. Lower-order constellations of QAM symbols may be assigned to subbands that include higher-frequency subcarriers and higher-order constellations of QAM symbols may be assigned to subbands that include lower-frequency subcarriers. A block error correction decoder may be synchronized based on an identification of the first constellation of QAM symbols and information identifying boundaries between the plurality of downlink symbols.

Abstract: Provided are a soft demapping apparatus and method that may cancel interference included in a rotated quadrature amplitude modulation (QAM) signal, using at least one interference cancellation unit, and may perform one-dimensional (1D) soft demapping of the interference-cancelled rotated QAM signal.

Abstract: A method and a system for calculating a JCMA constellation for use in a JCMA communication system where the method includes a step of using maximum sum-rate mutual information criterion to select an optimal JCMA constellation for the number of transmitters N, SNR and modulation schemes used by the transmitters.

Abstract: A method for transmitting to a UE control information comprising: channelization-code-set information (xccs,1, xccs,2, . . . , xccs,7); modulation-scheme and number of transport blocks information (xms,1, xms,2, xms,3, xms,4, xms,5); and precoding weight information (xpwipb,1, xpwipb,2, xpwipb,3, xpwipb,4). The method includes: multiplexing the channelization-code-set information, the modulation-scheme and number of transport blocks information and the precoding weight information to give a sequence of sixteen bits x1,1, x1,2, . . . , x1,16, where x1,i=xccs,i for i=1, 2, . . . , 7; x1,i=xms,i-7 for i=8, 9, 10, 11, 12; and x1,i=xpwipb,i-12 for i=13, 14, 15, 16; applying rate 1/2 convolutional coding to the sequence of bits x1,1, x1,2, . . . , x1,16 to obtain bit sequence z1,1, z1,2, . . . , z1,48; and puncturing the bits z1,1, z1,2, z1,4, z1,8, z1,42, z1,45, z1,47, z1,48 from sequence z1,1, z1,2, . . . , z1,48 to obtain an output sequence r1,1, r1,2 . . . r1,40.