Abstract: A method of decoding a signal transmitted via a multiple input multiple output (MIMO) communication channel. The method includes receiving a data symbol vector having a plurality of data symbols received via a plurality of spatial streams. The received data symbol vector corresponds to a transmitted data symbol vector having a plurality of transmitted data symbols corresponding to the plurality of data symbols. The method also includes estimating, using a hard-decision technique, one or more respective values for one or more first transmitted data symbols in a first set of one or more spatial streams. The method additionally includes calculating, using a soft-decision technique and based on the estimated one or more respective values for the one or more first transmitted data symbols, likelihood values for bits corresponding to one or more second transmitted data symbols in a second set of one or more spatial streams.

Abstract: Among other things, the present invention addresses timing issues related to a polarity control scheme in DFE implementation. Multiplexing that may be necessary for implementing a polarity control scheme is incorporated into multiplexing that may be required to convert half rate data into full rate data in a delay element of a DFE. Clocking signals are provided to a multiplexer that are encoded with polarity information. The various clock signals are generated using a clock generation circuit that incorporates polarity control.

Abstract: A Manchester code receiving circuit includes an analog circuit configured to convert an analog signal received through a communication transmission path, to a digital signal based on a Manchester code, and a characteristic compensating unit configured to compensate at least one of rise delay characteristics in which a rising time of the digital signal is longer than a falling time, and fall delay characteristics in which the falling time of the digital signal is longer than the rising time.

Abstract: A method includes identifying a signal peak from an input signal. The signal peak may be detected with peak detection circuitry. A serial division operation may be performed on the identified signal peak value with serial division circuitry to obtain a scaling factor. The peak detection circuitry may identify an additional signal peak from the input signal concurrently with the serial division operation. The serial division operation may be halted if the additional identified signal peak is greater than the previous identified signal peak. Another serial division operation may be performed based on the additional identified signal peak.

Abstract: An outdoor radio communication system housed in a single enclosure comprises a first transceiver, a second transceiver, a communication interface unit, an RF in-phase transmit combiner, an antenna coupling unit and a receive filter. The first transceiver includes a first receiver and a first transmitter. The second transceiver includes a second receiver and a second transmitter. The two transceivers are communicatively coupled with the communication interface unit. The RF in-phase transmit combiner, communicatively coupled to the first transmitter and the second transmitter, receives a phase-aligned RF signal from each transmitter, to create a third RF signal with enhanced signal gain. The two phase-aligned RF signals originate from the same source in the communication interface unit. The antenna coupling unit is communicatively coupled to the RF in-phase transmit combiner and the first receiver, and the receive filter is communicatively coupled to the second receiver.

Abstract: A method for reducing far-end crosstalk in an xDSL system is provided. The method includes transmitting, by a first DSL transceiver over a first line to a second DSL transceiver, a noise statistic related value that reflects a signal-to-noise ratio of the first line and receiving, by the first DSL transceiver over the first line from the second DSL transceiver, a synthesized signal pre-coded on the second DSL transceiver using filtering parameters associated with the noise statistic related value. The method further includes transmitting, by the first DSL transceiver over the first line to the second DSL transceiver in response to the reception of the synthesized signal, an updated noise statistic related value. A corresponding device for remote crosstalk cancellation is also provided.

Abstract: Good transmission characteristics are achieved in the presence of fading with a transmitter that employs a trellis coder followed by a block coder. Correspondingly, the receiver comprises a Viterbi decoder followed by a block decoder. Advantageously, the block coder and decoder employ time-space diversity coding which, illustratively, employs two transmitter antennas and one receiver antenna.

Abstract: An adaptive coding and modulation (ACM) apparatus and method for a forward link in satellite communication is provided. The ACM apparatus may include a receiving unit to receive a signal-to-noise ratio (SNR) of a received signal, a determination unit to determine whether the SNR of the received signal is less than or equal to a threshold value, and a processing unit to execute a channel prediction algorithm when the SNR of the received signal is determined to be less than or equal to the threshold value.

Abstract: A channel equalization scheme is provided. A linear equalizer using a continuous-time linear equalization and a decision feedback equalizer using a discrete-time decision feedback equalization are integrated together from a hybrid receiver equalizer. The continuous-time linear equalization scheme and the discrete-time decision feedback equalization scheme are blended using a joint adaptation algorithm to form an equalization scheme for inter-symbol interference cancellation in the hybrid receiver equalizer. The hybrid receiver equalizer controls crosstalk while maintaining signal bandwidth and linearity of a signal by the high-order high frequency roll-off of the linear equalizer used. Using this configuration, the hybrid receiver equalizer eliminates the need for adaptive bandwidth controller used in conventional low-pass receiver equalization schemes. The hybrid receiver equalizer can be used in receivers for dual-speed simultaneous transmission on the same physical link.

Abstract: Disclosed herein are a method and apparatus for generating multiband Radio Frequency (RF) signals in maritime wireless communication. The apparatus includes a baseband conversion unit, a phase compensation unit, a Direct Current (DC) offset compensation unit, and an RF transmission unit. The baseband conversion unit converts RF signals corresponding to a baseband modulation signal having a negative frequency and a baseband modulation signal having a positive frequency into baseband signals, respectively. The phase compensation unit eliminates the images of multiband signals so as to correspond to the baseband signals. The DC offset compensation unit compensates the baseband modulation signals for DC offsets using the multiband signals from which the images have been eliminated. The RF transmission unit generates the RF signals using the signals which have been compensated for the DC offsets, and sends the RF signals via an antenna.

Abstract: Methods and systems to vary an erasure slicer threshold based on a measure computed from prior soft and/or hard symbol decisions, identify reliable symbol estimates based on the threshold, identify unreliable symbol estimates for erasure based on the threshold, modify the identified symbol estimates, output the reliable symbol estimates and the modified symbol estimates as erasure slicer decisions, and filter the decisions in a feedback filter of a decision feedback equalizer (DFE). The erasure slicer threshold may be based on signal-to-noise ratio (SNR) or mean-squared-error (MSE). A symbol estimate may be identified for erasure when a coordinate of the corresponding soft decision is within an erasure area defined by the threshold. Symbol modification may include replacing a corresponding coordinate of the symbol estimate with a coordinate of a decision boundary associated with the erasure area.

Abstract: Techniques are provided to support soft handoff in a frequency hopping OFDMA system. Each sector concurrently supports “non-handoff” users and “soft-handoff” users. A non-handoff user communicates with only one sector, and a soft-handoff user communicates with multiple sectors simultaneously. Non-handoff users are assigned traffic channels by their sole sectors, and soft-handoff users are assigned traffic channels by their “serving” sectors. For each sector, the traffic channels assigned to the non-handoff users are orthogonal to one another and may or may not be orthogonal to the traffic channels assigned to the soft-handoff users. Each sector processes its received signal and recovers the data transmissions from the non-handoff users of that sector. Each sector then estimates the interference due to the non-handoff users and cancels the interference from the received signal. Each sector further processes its interference-canceled signal to recover the data transmissions from the soft-handoff users.

Abstract: A system and method are provided for implementing a soft Reed-Solomon (RS) decoding scheme, technique or algorithm to improve physical layer performance in cable modems and cable gateways. The algorithm is implemented in a forward error correction (FEC) module connected to a QAM demodulator. The RS decoding scheme is implemented without significantly complicating hardware or processing overhead. The soft Reed-Solomon (RS) decoding scheme extracts candidate RS symbols and their Log Likelihood Ratios (LLRs) from QAM symbols. The set of highest probable candidate blocks are then chosen and these are decoded using a variant of the Chase algorithm until a valid codeword is detected at the decoder output.

Abstract: There is provided a demodulation device including: a first noise elimination circuit eliminating a noise in an output signal of IQ coordinates from a demodulation unit demodulating an input signal, in which the first noise elimination circuit includes: a first subtracter subtracting a first noise replica signal from the signal of the IQ coordinates that is output from the demodulation unit; an error information generation unit calculating error information of an output signal of the first subtracter to an ideal signal point of the IQ coordinates; a first frequency detection unit detecting a frequency of the noise based on the error information; and a first amplitude adjusting unit adjusting an amplitude of the first noise replica signal based on the error information and the frequency of the noise detected in the first frequency detection unit to output the first noise replica signal to the first subtracter.

Abstract: Techniques for rotating and transmitting multidimensional constellations are disclosed. A method for rotating a multidimensional constellation may include constructing a first rotation matrix, constructing a second rotation matrix, applying orthogonality constraints to the first and second rotation matrices; selecting an optimizing rotation matrix from the first and second rotation matrices; and rotating the multidimensional constellation using the optimizing rotation matrix. Constructing the first rotation matrix and second rotation matrices may include constructing a first column that includes first matrix elements based on the number of axes in the multidimensional constellation, and additional columns that include permutations of the first matrix elements.

Abstract: A transmitting apparatus transmits signals in a digital telecommunication system and a synchronising method is used for synchronizing such signals at a receiving apparatus. The transmitting apparatus prepares for transmission a reference symbol having at least two repetition patterns, whereby one of the at least two repetition patterns is phase-shifted in relation to the other repetition pattern, and a synchronizing mechanism in the digital telecommunication system uses the reference symbol once received for synchronization. The synchronizing mechanism uses a cross-correlation mechanism to cross-correlate at least one of the two repetition patterns within a correlation window having a predetermined length.

Abstract: A method for mapping data in a wireless communication system. The method includes generating a precoding matrix for multi-antenna transmission based on a precoding matrix indicator (PMI) feedback from at least one remote receiver where the PMI indicates a choice of precoding matrix derived from a matrix multiplication of two matrices from a first code book and a second codebook. The method further includes precoding one or more layers of a data stream with the precoding matrix and transmitting the preceded layers of data stream to the remove receiver.

Abstract: An reception device includes: a fast-fourier-transform (FFT) circuit to FFT a first Orthogonal Frequency Division Multiplexing (OFDM) signal including a plurality of first symbols with a guard interval and a valid symbol using a plurality of FFT windows that includes different timings within a symbol length period; a propagation channel estimation circuit to extract pilot signals from the fast-fourier-transformed first OFDM signal, and estimate a plurality of propagation channel characteristics of the plurality of first symbols based on the pilot signals; and a propagation channel compensation circuit to obtain a propagation channel characteristic of a second symbol without a pilot signal based on the plurality of propagation channel characteristics and remove the propagation channel characteristic of the second symbol from a second OFDM signal obtained by fast-fourier-transforming the second symbol.

Abstract: One embodiment of the present invention relates to a communications system. The system includes a Highway-Addressable Remote Transducer (HART) transmitter comprising a direct memory access (DMA) module configured to access at least one transmitter lookup table (LUT) using DMA transfers to modulate a HART data packet into a frequency-shift keying (FSK) data signal. The system also includes a HART receiver configured to demodulate a received FSK data signal into a demodulated HART data packet.

Abstract: Provided is a communication apparatus which calculates a CQI indicating reception quality of a reception signal in a receiver and feeds back the CQI to a transmitter, the CQI containing information obtained by averaging SNRs of a plurality of subbands, which are generated by dividing a reception band into a predetermined number, in the reception band, the communication apparatus including a CQI/PMI/RI estimation unit directly uses an initial value in a predetermined approximation method as an approximation calculation result obtained by the predetermined approximation method to thereby simplify the calculation, when the predetermined approximation method is used for calculation in the averaging in place of root calculation and when values of the SNRs are high.