Abstract: A technique involves using a fast Fourier transform (FFT) module to transform multiple different types of signals. This may be accomplished using one or more of three techniques: logic within the FFT module can enable different processing depending upon a processing state, the FFT module can be called iteratively to transform a signal that is larger than the FFT implemented in the FFT module, the FFT module can be used for parallel transformation of multiple signals that are smaller than the FFT implemented in the FFT module. Thus, a single FFT module can be used to transform a first type of signal (e.g., WIFI) and a second type of signal (e.g., GPS) if configured according to the technique.

Abstract: Communication systems are described that use signal constellations, which have unequally spaced (i.e. ‘geometrically’ shaped) points. In many embodiments, the communication systems use specific geometric constellations that are capacity optimized at a specific SNR. In addition, ranges within which the constellation points of a capacity optimized constellation can be perturbed and are still likely to achieve a given percentage of the optimal capacity increase compared to a constellation that maximizes dmin, are also described. Capacity measures that are used in the selection of the location of constellation points include, but are not limited to, parallel decode (PD) capacity and joint capacity.

Abstract: An RF unit receives multicarrier signals via a plurality of antennas. A division unit divides the multicarrier signals received into a plurality of groups in the frequency domain. The division unit acquires the channel quality for each subcarrier, contained in the multicarrier signal, in the frequency domain, and defines the plurality of groups according to the channel quality. The processing unit performs adaptive array signal processing for each of the divided groups.

Abstract: A reception apparatus including: a detection unit detecting extrinsic information based on a tentative symbol decision signal, a channel estimation signal, a noise variance estimation signal, and a received signal that are obtained from a previous iteration process; a Cyclic Redundancy Check (CRC) aided channel decoding unit outputting an interleaved bit or a posteriori information thereof based on the extrinsic information; a tentative symbol decision unit determining a tentative transmission symbol based on an output of the CRC aided channel decoding unit; a channel estimation unit estimating a channel based on an output of the tentative symbol decision unit; and a noise variance estimation unit estimating a noise variance based on the output of the tentative symbol decision unit and an output of the channel estimation unit is provided.

Abstract: Provided is a maximum likelihood decoding method of separating and estimating multiple transmitted signals transmitted by multiple transmitter antennas from multiple received signals received by multiple receiver antennas, comprising: a first step of generating a channel matrix based on channel impulse responses corresponding to the received signals; a second step of dividing the generated channel matrix into multiple sub-matrices, of identifying parts of the received signals corresponding to the sub-matrices obtained through the division, and of transforming the sub-matrices obtained through the division, by using inverse matrices of the sub-matrices obtained through the division; a third step of applying QR decomposition to the transformed sub-matrices to obtain triangular matrices, and of transforming the received signals of the parts by using the obtained triangular matrices; and a fourth step of determining one combination candidate for the parts of the transmitted signals corresponding to the transforme

Abstract: An apparatus for trellis-based detection in a communication system including a processor and memory having computer program code configured to construct a trellis representing a transmitted signal formed from a plurality of symbols, each having a constellation size, transmitted by a number of transmit antennas, and form a log likelihood ratio at nodes of the trellis as a log-sum of a number of exponential terms including a priori information corresponding to a hypothesized transmitted bit value of the plurality of symbols. The number of exponential terms is limited by a number of most likely paths of the trellis extending from each node of the trellis and the constellation size. The processor and memory including computer program code are configured to form a list at each node of the trellis of a size limited to the number of the most likely paths of the trellis extending from each node.

Abstract: A User equipment selecting first user equipment in a mode of precoding transmission and second user equipment in a mode of diversity transmission; a parameter determining a modulation mode, the number of transmission layers and a precoding matrix according to channel quality information, precoding matrix information and number of transmission layers sent from the first user equipment and channel quality information and number of transmission layers sent from the second user equipment; according to the modulation mode and the number of transmission layers, generating first and second symbol sequence from first and second source data; hierarchically modulating the first and the second symbol sequence to generate a mixed symbol sequence; layer mapping and precoding for the mixed symbol sequence to generate transmission signals; and transmitting the precoding matrix and the number of transmission layers to the second user equipment; sending the transmission signals to the first and second user equipments.

Abstract: Aspects of a method and system for predicting CQI values for ML detection in a 2×2 MIMO system are presented. In one aspect of the system, a CQI value for a MIMO communication system may be computed based on a computed channel realization by reverse mapping the computed channel realization to a corresponding CQI value. Based on the computed CQI value, a coding rate may be selected. The coding rate may be selected from a lookup table, wherein the computed CQI value is utilized as an index to the lookup table. The reverse mapping may utilize a function, which is computed using radial basis function networks. In another aspect of the system, a joint mutual information value may be computed for the MIMO communication system. The joint mutual information value may be computed based on a Shannon mutual information value and a matched filter mutual information value.

Abstract: Embodiments of the present invention provide a method, an apparatus, and a system for signal transmission. The method includes: obtaining, by a base station, a high-power precoding matrix and a low-power precoding matrix according to channel quality information, precoding a corresponding high-power signal stream according to the high-power precoding matrix respectively to obtain a first signal stream, precoding a corresponding low-power signal stream according to the low-power precoding matrix respectively to obtain a second signal stream, superimposing the first signal stream and the second signal stream to obtain one or more superimposed signal streams and transmitting the one or more superimposed signal streams to user terminals; decoding, by the user terminals, the received one or more superimposed signal streams by using receiving matrices, and obtaining signal streams that the user terminals need.

Abstract: A method for communication includes receiving a communication signal conveying multiple encoded bits of an Error Correction Code (ECC). Respective N-bit soft decoding metrics are computed with respect to the bits of the ECC. A scaling factor is computed based on at least one characteristic of the N-bit soft decoding metrics and on at least one property of the received communication signal. The N-bit soft decoding metrics are scaled by the scaling factor. The scaled N-bit soft decoding metrics are quantized to produce respective K-bit metrics, K<N. The ECC is decoded using the scaled and quantized soft decoding metrics.

Abstract: At a node of a wireless network, equalization operations performed on signals received from a transmitter are adaptively switched to be equalized by an iterative turbo receiver or a linear receiver. A theoretical expression of a post-equalization SINR of a capacity-achieving receiver is used to estimate the post-equalization SINR performance of the turbo receiver. The estimated post-equalization SINR performance is then used as a basis to determine whether the received signal is to be equalized by the turbo receiver or the linear receiver.

Abstract: A mobile terminal with smart antennas, comprises a plurality of groups of radio frequency signal processing modules (300), for transforming received multi-channel radio frequency signals to multi-channel baseband signals; a smart antenna processing module (306), for smart antenna baseband processing said multi-channel baseband signals output from said plurality of groups of radio frequency signal processing module so as to combine said multi-channel baseband signals into single-channel baseband signals, according to control information received one-off as said smart antenna processing module is enabled; and a baseband processing module (303-305), for providing said control information to said smart antenna processing module according to data from said smart antenna processing module, and baseband processing said single-channel baseband signals outputted from said smart antenna processing module.

Abstract: Techniques for performing detection and decoding at a receiver are described. In one scheme, the receiver obtains R received symbol streams for M data streams transmitted by a transmitter, performs receiver spatial processing on the received symbols to obtain detected symbols, performs log-likelihood ratio (LLR) computation independently for each of D best data streams, and performs LLR computation jointly for the M?D remaining data streams, where M>D?1 and M>1. The D best data streams may be selected based on SNR and/or other criteria. In another scheme, the receiver performs LLR computation independently for each of the D best data streams, performs LLR computation jointly for the M?D remaining data streams, and reduces the number of hypotheses to consider for the joint LLR computation by performing a search for candidate hypotheses using list sphere detection, Markov chain Monte Carlo, or some other search technique.

Abstract: Systems and methodologies are described that provide low-complexity soft-output detection for MIMO communication systems. Looping can be performed over a set of constellation points per spatial stream to obtain distance metrics for each of a series of transmitted streams, for which values for the other transmitted streams can be estimated using a MIMO channel matrix and a sub-optimal MIMO algorithm. Examples of MIMO algorithms that can be utilized include Per-Stream List Detection (PSLD), Lattice-Reduced Detection (LRD), and a Guided-M Algorithm. Performance can be further improved by pre-processing the MIMO channel matrix and/or by utilizing techniques for Enhanced Metric Usage (EMU).

Abstract: A system and method for receiving a RF signal, comprising a device for digitizing, without prior alteration of frequency, an analog RF representation of each of a plurality of RF signals to produce a respective plurality of digital RF signals having a respective associated RF digital clock, the plurality of digital RF signals having a sufficiently high respective associated clock rate to preserve an information content of an information communication present in the analog RF representation; a switch matrix adapted to concurrently switch the plurality of digital RF signals and associated digital RF clock to ones of a plurality of digital signal processors; and a control adapted to selectively automatically control the concurrent switching of a plurality of digital signals and associated digital clock to the respective plurality of digital signal processors; wherein the digital signal processors produce processed representations of information contained in respective analog RF representations.

Abstract: A method and system are provided for minimizing errors by retransmitting packets in a multiple-input-multiple-output (MIMO) space-time coded packet radio. A packet is transmitted using a first STC code mapping, the mapping including well-known symbol operations, and optional signal weighting. When transmission errors are detected the packet is re-transmitted using STC code mappings selected in turn from a deterministic sequence of STC code mappings. The STC code mappings are chosen in accordance with one or more principles.

Abstract: A non-linear detector for detecting signals with signal-dependent noise is disclosed. The detector may choose a data sequence that maximizes the conditional probability of detecting the channel data. Since the channel may be time-varying and the precise channel characteristics may be unknown, the detector may adapt one or more branch metric parameters before sending the parameters to a loading block. In the loading block, the branch metric parameters may be normalized and part of the branch metric may be pre-computed to reduce the complexity of the detector. The loading block may then provide the branch metric parameters and any pre-computation to the detector. The detector may then calculate the branch metric associated with the input signal and output the channel data.

Abstract: Methods of transmitting an receiving symbols by a Mobile Subscriber Station (MSS) and a Base Station (BS) are provided. The method for receiving symbols by the MSS includes receiving symbols from the BS, wherein the symbols are mapped onto data sub-carriers using a sequence, wherein the sequence includes result values, the result values being generated by applying, to a basic sequence, an offset and a number of cyclic shifting, the basic sequence having a length identical to the number of data sub-carriers. The method for transmitting symbols by the MSS includes transmitting symbols to the BS, wherein the symbols are mapped onto data sub-carriers using a sequence, wherein the sequence includes result values, the result values being generated by applying, to a basic sequence, an offset and a number of cyclic shifting, the basic sequence having a length identical to the number of data sub-carriers.

Abstract: Embodiments of the present invention provide a read channel including a front end to receive an optical image, convert the optical image into multi-bit soft information, and to serially transmit the multi-bit soft information to other components of the read channel. Other embodiments may be described and claimed.

Abstract: A radio communication apparatus includes a receiving unit configured to receive signals, an obtaining unit configured to obtain a reference amplitude that depends on a modulation scheme for a received signal received by the receiving unit, and on amplitude fluctuations of the received signal in a propagation path, a demodulating unit configured to demodulate the received signal to obtain an in-phase component and a quadrature component of each received symbol included in the received signal, a calculating unit configured to calculate a likelihood ratio for each of bits mapped to each received symbol using the reference amplitude and the in-phase or quadrature component, and a decoding unit configured to perform error correction decoding on the received signal using the calculated likelihood ratios.

Abstract: Techniques for transmitting signaling with localized spreading are described. In one design, a transmitter (e.g., a base station) spreads multiple signaling symbols to obtain multiple sets of output symbols and further maps the multiple sets of output symbols to multiple time frequency blocks. The spreading may be localized to each time frequency block. Prior to the spreading, the transmitter may scale the multiple signaling symbols with multiple gains determined based on the transmit power for these signaling symbols. The transmitter may scramble the scaled signaling symbols to obtain scrambled symbols and may spread the scrambled symbols to obtain the multiple sets of output symbols. The transmitter may map each set of output symbols to a respective time frequency block.

Abstract: A technique for wirelessly transmitting management data without cables in a data center is provided. Management data is obtained at a device in the data center. A wireless management data signal is generated from the management data. The wireless management data signal is configured to be transmitted at frequencies matching an ambient electromagnetic noise emitted by the data center, such that the wireless management data signal is masked in the ambient electromagnetic noise emitted by the data center. The wireless management data signal is wirelessly transmitted to another device.

Abstract: A method for receiving a broadcasting signal and a broadcasting signal receiver are disclosed. Even when a cell is changed while an emergency alert is output, the emergency alert can be continuously output using emergency alert table information included in the broadcasting signal and channel information of the cell. The emergency alert table information may include a cell identifier and the channel information of the cell may include virtual channel information of the cell.

Abstract: A method for detecting validity of downlink control information in telecommunication user equipment and a decoder and baseband receiver to perform the method are provided. The object of avoiding falsely detecting payload data and misinterpreting them is achieved by reverse encoding a bit output sequence of a Viterbi decoder; determining hard bits from a soft-bit input sequence of the decoder; determining a bit count of real received bits; comparing the reverse encoded bit stream to the determined hard bit stream and counting the number of mismatches to obtain an error count; comparing a bit error rate which is defined as a quotient of the error count and the bit count against a predefined threshold value; and rejecting the payload as invalid if said bit error rate is above said threshold value, even if a cyclic redundancy check of the payload gives a correct result.

Abstract: A method and apparatus for transmitting data having time diversity and data having time-frequency diversity, and a pattern generating method for the same are disclosed. The apparatus enables Tx data to have time diversity or time frequency diversity using a predetermined pattern multiplied by Tx data of a time domain or Tx data of time and frequency domains. The apparatus makes a cyclic delay diversity (CDD) scheme to have the diversity of time and frequency domains, and may acquire an additional diversity gain by a combination of the above-mentioned methods.

Abstract: An impulse radio communication device includes a short pulse generator configured to change a shape of an impulse to be output; a bandpass filter configured to receive the impulse and output the impulse as a wave packet; an amplifier configured to amplify an output from the bandpass filter; and an antenna configured to output the wave packet, output from the amplifier, as a wireless signal, the short pulse generator includes a control section configured to change the shape of the impulse to be output, in response to an environmental condition of a transmission path for wireless communication.

Abstract: A signal demultiplexing method and apparatus are provided, for determining a likelihood of each bit included in a second signal, which is spatially multiplexed with and received with a first signal, based on a maximum likelihood detection (MLD) method using QR decomposition, wherein the first signal excludes the second signal to be calculated only in a final stage of the MLD method.

Abstract: An integrated circuit includes logic configured to encode one or more first data symbols in one or more first sub-carriers as one or more second data symbols in one or more second sub-carriers of a smart-utility-network communication.

Abstract: A communication apparatus carries out multicarrier communication with another communication apparatus through a transmission channel. The communication apparatus includes a first communication unit which carries out communication using a subcarrier at a first frequency band; a second communication unit which carries out communication using a subcarrier at a second frequency band higher than the first frequency band; and a third communication unit which carries out communication by synchronizing the first communication unit with the second communication unit and concurrently using the first and second frequency bands.

Abstract: A transmitting terminal includes a signal processing unit, MS RF units, MT transmit antennas and a switch unit. The signal processing unit has K precoders for precoding K data streams corresponding to K receiving terminals. The MS RF units output MS up-converted transmit signals based on the precoded K data streams. The switch unit is coupled between the RF units and the transmit antennas and controlled by the signal processing unit for selection of the transmit antennas. The signal processing unit sets the MT transmit antennas as a universal set, calculates a plurality of sum rates corresponding to a plurality of subsets, each subset excluding an ith transmit antenna, according to channel state information, selects the subset with a maximum sum rate as the universal set of a next iteration, and then repeats the calculating and selecting steps until the subset with the maximum sum rate remaining MS transmit antennas.

Abstract: A method select a codebook for transmit beamforming. The method constructs an estimated channel matrix based on a codebook, selects a channel submatrix from the estimated channel matrix, calculates a selection matrix from the channel submatrix; and assigns a steering matrix based on the selection matrix. There may be multiple codebooks and the method may construct an estimated channel matrix, select a channel submatrix, and calculate a selection matrix for each of the codebooks, then select an optimal codebook. The steering matrix is assigned based on the optimal codebook. The steering matrix may be used in steering a transmitted packet. The method may also calculate a post-MIMO equalizer signal-to-noise ratio for a data stream, based on the estimated channel matrix and the selected codebook. A related system is also disclosed. Other embodiments are provided, and each of the embodiments described herein can be used alone or in combination with one another.

Abstract: A method for QR-maximum likelihood detection (QR-MLD) demodulation is provided. The method includes determining a transmission reception mode, receiving symbols represented by a received symbol vector, generating a channel matrix, and performing QR decomposition on the channel matrix to compute a unitary matrix and an upper triangular matrix. The method further includes the steps of processing the received symbol vector by multiplying the received symbol vector by the Hermitian of the unitary matrix, determining whether a conjugate calculation will be required to set a conjugate flag, computing a first distance metric by performing a conjugate or non-conjugate first distance metric calculation depending on the conjugate flag, and computing an estimated symbol by performing a conjugate or non-conjugate estimated symbol calculation depending on the conjugate flag.

Abstract: A network controller receives data substantially simultaneously from multiple client nodes. The network controller assigns to each client node one or more sub-carriers of an orthogonal frequency-division multiplexing access frequency spectrum. The client nodes transmit substantially simultaneously M LDPC codewords that are encoded in a parity check matrix so that the number of rows m? depend on the code rate and are mapped on its assigned sub-carriers. The network controller computes a bit log-likelihood ratio for each received bit of the codewords and arranges the bit LLR by codeword to align with an equivalent parity check matrix. The network controller decodes the codewords with the equivalent parity check matrix.

Abstract: Two decoding algorithms are introduced for the decoding of multi-level coded modulation and other types of coded modulation involving component codes and interleaving operations. An improved hard iterative decoding (IHID) algorithm is presented that improves upon a hard iteration decoding technique by adding a stopping criterion. Also, a list Viterbi hard iteration decoding (LV-IHID) algorithm is presented that employs list decoding in conjunction with the IHID algorithm. Both of these decoding algorithms improve upon conventional multi-stage decoding by reducing the effective error multiplicity that is observed at the lowest coding level. It is demonstrated that the LV-IHID algorithm performs close to soft iterative decoding. The computational and delay complexity of the proposed decoding algorithms compare favorably with soft iterative decoding strategies. Also, a novel labeling strategy for MLC design is presented.

Abstract: A communication system includes a transmitter which generates transmit phase points defined to be the vector sum of two or more QPSK signals. Forward error correction encoding is performed independently for the QPSK signals. In a receiver, alternate hypotheses are formed about the potential values that might have been transmitted for all the QPSK signals, and offset phase points are defined for each hypothesis. For the correct hypothesis, the offset phase point has the effect of canceling all the two or more QPSK signals from the combined communication signal leaving only circuit and channel noise added during transmission. Branch metrics are responsive to Euclidean distances between the received signal and the hypothesized transmitted signal. A decoder is configured to accept and reject the hypotheses based on the noise statistics and desired communication application symbol error rate.

Abstract: A plurality of received data symbols is received, and a first received data symbol is selected from the plurality of received data symbols. A plurality of global optimum candidate values of a first estimated transmitted data symbol corresponding to the first received data symbol is determined for different given candidate values of second estimated transmitted data symbols corresponding to second received data symbols. Likelihood values for bits corresponding to the second estimated transmitted data symbols are calculated using the plurality of global optimum candidate values. All possible values of the first estimated transmitted data symbol are grouped into two or more bit groups, and a plurality of local optimum candidate values are determined for different bit groups. Likelihood values for bits corresponding to the first estimated transmitted data symbol are calculated using the plurality of global optimum candidate values and the plurality of local optimum candidate values.

Abstract: A multi-user MIMO downlink beamforming system with limited feedback (200) is provided to enable precoding for multi-stream transmission, where a channel codeword (ui) and one or more channel quality indicator values (CQIA, CQIB) are computed at the user equipment (201.i) on the basis of maximizing a predetermined SINR performance metric (?i) which estimates the receive signal-to-noise-ratio (SINR) at the user equipment (201.i). The computed codeword (ui) and CQI values (or differential values related thereto) are quantized and fed back to help the base station (210) which applies a correction to the appropriate CQI value in the course of designing the transmit beamforming vectors w and determining the appropriate modulation and coding level to be used for downlink data transmission.

Abstract: In various aspects, the disclosure describes systems and methods for decoding of convolutionally encoded signals representing, for example, telecommunications signals such as command or content signals used in digital telecommunications. In various embodiments such aspects of the disclosure provide systems and methods for improving the efficiency, speed, and power consumption of such processes by providing architectures and methods for processing various parts of the encoded data records in parallel, using multiple and optionally specially-designed, dedicated memory registers and multiplexers.

Abstract: A method for processing a plurality of data streams from a transmitter, includes: receiving symbols via the plurality of data streams; generating a channel matrix; sorting the channel matrix to provide a sorted channel matrix; performing QR decomposition on the sorted channel matrix and a column-row-swapped-sorted-channel matrix; performing QR equalization on a sorted received symbol vector and a swapped received symbol vector to provide a equalized-sorted vector and a equalized-swapped-sorted vector; processing first and second portions of the equalized-sorted vector and the equalized-swapped-sorted vector via a QR-MLD demodulation scheme to determine soft bits and soft symbols; and rearrange soft bits in the above steps to provide an output vector.

Abstract: A MIMO receiver is provided with a preprocessor for performing QR decomposition of a channel matrix H wherein the factored reduced matrix R is used in place of H and Q*y is used in place of the received vector y in a maximum likelihood detector (“MLD”). The maximum likelihood detector might be a hard-decision MLD or a soft-decision MLD. A savings of computational complexity can be used to provide comparable results more quickly, using less circuitry, and/or requiring less consumed energy, or performance can be improved for a fixed amount of time, circuitry and/or energy. Where the MLD uses approximations, such as finite resolution calculations (fixed point or the like) or L1 Norm approximations, the reduced number of operations resulting from using the reduced matrix results in improved approximations as a result of the finite resolution operations. Other methods of reducing the channel matrix might be used for suitable and/or cumulative advantages.

Abstract: A system for compensating for in-phase and quadrature (I/Q) imbalances for multiple antenna systems (MAS) with multi-user (MU) transmissions (defined with the acronym MU-MAS), such as distributed-input distributed-output (DIDO) communication systems, comprising multicarrier modulation, such as orthogonal frequency division multiplexing (OFDM).

Abstract: Systems and methods for reconstructing digital information in a multiple-input receiver from signals transmitted by a multiple-output transmitter, in a multiple-input multiple-output (MIMO) communications channel are provided. A plurality of signal streams are obtained from a plurality of transmitted signals and a first candidate signal value is selected for each of the plurality of signal streams. A plurality of additional candidate signal values are also selected for each of the plurality of signal streams in response to selecting the first candidate signal value. A log-likelihood ratio (LLR) is computed from the plurality of signal streams based on all of the selected candidate signal values. Digital information may then be estimated based on the computed LLR.

Abstract: Provided is a multi-antenna transmission device (400) which can perform MLD by using a simple configuration of a reception device in a MIMO-AMC system. The multi-antenna transmission device (400) includes common signal point mapping units (401, 402) for mapping data transmitted from different antennas (111, 112) in transmission scheme using MIMO spatial multiplexing, to common signal points shared by respective modulation methods. Thus, the arrangement of baseband signal points obtained by mapping a code word after channel encoding onto an IQ plane can be shared as common signal points shared by modulation methods. Accordingly, the reception device need not prepare a particular circuit for performing MLD calculation in accordance with a combination of the methods for modulating the signals which have been MIMO-space multiplexed. This can reduce the circuit size of the MLD calculation circuit.

Abstract: A disclosed base station apparatus is capable of communicating with a user equipment terminal in a multi-input multi-output (MIMO) mobile communication system using Pre-coding. The base station apparatus includes a receiving unit receiving a Pre-coding Matrix Indicator (PMI) indicating a specific Pre-coding matrix, a determination unit determining a value of a flag indicator indicating whether the Pre-coding matrix specified in the PMI is to be used for downlink communications, a control signal generation unit generating a downlink control signal including at least the flag indicator, and a transmission unit transmitting a signal including the downlink control signal in downlink.

Abstract: A method is provided for decoding a signal received by a receiver including at least one reception antenna. The method includes: selecting, among at least two techniques available in the receiver, a decoding technique representative of a space/time encoding implemented upon transmission; and decoding the signal using the selected decoding technique. The selecting step takes into account at least one selection criterion.

Abstract: A base station allowing mobile stations to efficiently remove interference signals. In this base station, an encoding part performs an error correction encoding of transport data to generate a bit sequence comprising systematic bits and parity bits; a repetition part repeats, as a repetition subject, only the parity bits out of the plurality of bits included in the bit sequence, which is generated by the encoding part, so as to perform a rate matching; a modulating part modulates, after the repetition, the bit sequence to generate symbols; an S/P part parallel converts the symbols serially inputted from the modulating part (103) and then outputs them to an IFFT part; and the IFFT part performs an IFFT processing of the symbols inputted from the S/P part and then maps them onto subcarriers in accordance with a predetermined mapping pattern, thereby generating OFDM symbols.

Abstract: A discrete cosine transform (DCT)-based orthogonal frequency-division multiplexing (OFDM) system is provided with a zero-padding guard interval and MMSE reception. The performance of the DCT-OFDM system with the zero-padding guard interval scheme and the minimum mean-square error (MMSE) receiver over time-varying multipath Rayleigh fading channels is investigated. The results show that employing the proposed DCT-OFDM system rather than the conventional DFT-OFDM system can provide better bit error rate performance in practical systems, by as much as 6 dB in signal-to-noise ratio.

Abstract: A technique for wirelessly transmitting management data without cables in a data center is provided. Management data is obtained at a device in the data center. A wireless management data signal is generated from the management data. The wireless management data signal is configured to be transmitted at frequencies matching an ambient electromagnetic noise emitted by the data center, such that the wireless management data signal is masked in the ambient electromagnetic noise emitted by the data center. The wireless management data signal is wirelessly transmitted to another device.

Abstract: Crest factor reduction algorithms described herein may be used to improve power amplifier efficiency during low signal power conditions compared to traditional static threshold techniques. Techniques described herein insure that the signal power level at the output of the crest fact reduction block is held constant relative to the input power level under all signal power level conditions. Two different solutions may be implemented together or separately to achieve the desired conditions. The first technique provides constant ratio between input power and output power. Constant ratio of peak and average output levels keeps the amount of crest factor reduction applied to the signal constant, irrespective of the signal power level. A second technique is to hold signal power level constant in respect to the amount of crest factor reduction applied.

Abstract: The semiconductor integrated communication circuit includes: a low-noise amplifier; a receive mixer; a receive VCO; a demodulation-processing circuit; a modulation-processing circuit; a transmit mixer; a transmit VCO; a second-order-distortion-characteristic-calibration circuit; a quadrature-receive-signal-calibration circuit; and a test-signal generator. The test-signal generator generates first and second test signals using the transmit VCO. In the second-order-distortion-characteristic-calibration mode, the second-order-distortion-characteristic-calibration circuit variably changes an operation parameter of the receive mixer thereby to calibrate the second-order distortion characteristic to achieve its best condition while the first test signal is supplied to the receive mixer.