Abstract: A direct conversion multi-band TV tuner includes: a plurality of RF (radio frequency) paths for processing the RF signal and for generating a plurality of processed RF signals, respectively; and a TSC (tri-state chopper) based quadrature frequency converter for receiving one of said processed RF signals and converting the received processed RF signal into a in-phase baseband signal and a quadrature baseband signals; wherein the TSC based quadrature frequency converter operates in accordance with a first set of periodic three-state control signals and a second set of periodic three-state control signals that are approximately 90 degrees offset from the first set of periodic three-state control signals.

Abstract: A mixer circuit accumulates I signal (digital signal of first channel) having its band limited by low-pass filter and first carrier signal to perform two-phase shift keying modulation thereon. An adder adds fundamental-wave component of bit clock signal BCK into Q signal (digital signal of second channel) having its band limited by the another low-pass filter to obtain a resultant added-up signal. Another mixer circuit accumulates the added-up signal and second carrier signal to perform two-phase shift keying modulation thereon. Output signals of the mixer circuits are input to another adder so that they may be added up to obtain a QPSK signal as a modulated quadrature signal. The QPSK signal contains frequency signals whose frequencies are a sum of bit clock frequency and carrier frequency and a difference between them. When demodulating, the carrier signal and the bit clock signal are reproduced using the frequency signals.

Abstract: A system and method to optimize the quality of a modulated signal. In one aspect, an AM demodulator is used in conjunction with proper bandwidth selection of an FM signal. For example, the AM demodulator can be used to generate an instantaneous absolute value of the FM signal. The average value of the FM signal over a period of time is subtracted from the instantaneous absolute value in order to determine a variance in amplitude in the FM signal. In another aspect, several filters may be tested and the one having the lowest variance in amplitude may be used in order to select the filter having the desirable bandwidth.

Abstract: A decoder includes a sample rate conversion module, a decoding module, and an error sensing module. The sample rate conversion module is operably coupled to convert, based on an error feedback signal, rate of an encoded signal from a first rate to a second rate to produce a rate adjusted encoded signal. The decoding module is operably coupled to decode the rate adjusted encoded signal to produce a decoded signal. The error sensing module is operably coupled to produce the error feedback signal based on the decoded signal.

Abstract: Frequency demodulation of a signal is disclosed. A first edge event and a second edge event are detected in a signal. The second edge event is an edge event subsequent in time to the first edge event. A data bit based at least in part on a timing interval between the first edge event and the second edge event is determined.

Abstract: In general, this disclosure describes techniques for demodulating wireless signals. In particular, the techniques of this disclosure dynamically select between two or more demodulators based on channel quality information measured over a plurality of measurement periods. For example, a wireless communication device (WCD) may switch from a first demodulator to a second demodulator when the channel quality information associated with the demodulators indicates a better channel quality for the second demodulator than the first demodulator for a consecutive number of measurement periods. As another example, the WCD may compute, for each measurement period, the difference between the channel quality information associated with each of the demodulators, sum the differences, and switch demodulators when the total accumulation of the differences exceeds a threshold.

Abstract: An m-code GPS receiver receives m-code GPS communication signals having a multimodal autocorrelation, using an m-code mode identifier unambiguously determining a mode value of one of the m-code modal peaks coherently aligned to a coherent unimodal detected envelope, based on sequential probability estimation in an m-code envelope tracking filter using filter residual estimation or with a coherent m-code and c/a-code tracking filter also based on filter residual estimation, for generating m-code phase errors, for unambiguous and precise m-code code phase tracking in closed feedback loops, for preferred use in navigation systems.

Abstract: The present invention is directed to a quick, low-distortion and efficient reduction in sample rate requiring minimal logic. An IF signal is passed into an analog-to-digital converter. The converted signal is mixed with the combination of an in-phase and a quadrature component. The mixed signal is then split into an in-phase signal and a quadrature signal. The quadrature signal is interpolated to form a new signal aligned in time to the in-phase signal. Alternatively, the in-phase signal is interpolated to form a new signal aligned in time to the quadrature signal. The interpolation may comprise linear interpolation or parabolic interpolation. The simplified signal processing reduces the sample rate of the signal and the interpolation reduces aliasing introduced by the simplification. One advantage of this approach is that only half of the signal needs to be processed.

Abstract: A receiver circuit controls a power source of a front-end circuit and a demodulator using a first power source control signal. Upon receiving data of a plurality of receiving slots having a guard bit provided between receiving slots adjacent to each other, the first power source control signal becomes a power source ON signal before starting receiving of the data, then becomes a power source OFF signal within the guard bit, and becomes a power source OFF signal after completing the receiving of the data. The receiver circuit controls a power source of an active filter circuit using a second power source control signal, which becomes a power source OFF signal after completing the receiving of the data after becoming a power source ON signal before starting the receiving of the data.

Abstract: The present invention is directed to a method, apparatus and system for detecting the mode and the guard interval of a received orthogonal frequency division multiplexing (OFDM) symbol, which includes a guard interval with length Ng, and a useful part with length Nu. Mode is detected by searching for the maximum correlation or statistics value based on one (for example, the shortest one) guard interval length. Further, guard interval is detected by searching for the maximum correlation value based on all guard interval lengths.

Abstract: In-phase (I) and quadrature-phase (Q) signals are corrected for both amplitude and phase imbalances by passing the I and Q signals successively through a first amplitude correction stage, a sum-difference stage, and a second amplitude correction stage. The first amplitude correction stage balances the signal levels of the I and Q signals. The sum-difference stage produce a sum of the input I and Q signals, and a difference of the input I and Q signals, resulting in ideal quadrature in the outputs produced. The second amplitude correction stage corrects the amplitude differences from the sum-difference stage. Circuit configurations are used that minimize errors produced by the signal processing stages.

Abstract: A wireless apparatus includes: an A/D converter which samples an in-phase signal component and a quadrature signal component from a quadrature-modulated signal of analog form alternately; a digital quadrature demodulation unit which applies digital quadrature demodulation to an output signal of the A/D converter and outputs an in-phase signal and a quadrature signal; and an error detection unit which, based on the in-phase and quadrature signals output from the digital quadrature demodulation unit, detects a time difference error between the sample timing of the in-phase signal component and the sample timing of the quadrature signal component.

Abstract: A method for demapping dual carrier modulated COFDM signals comprises normalizing an estimated channel state information signal to obtain a normalized channel state information signal, determining a Y-domain weighting factor from the normalized channel state information signal, determining an X-domain weighting factor from the normalized channel state information signal, performing equalization on a received data OFDM signal to obtain an equalized data signal, weighting an equalized data signal using the Y-domain weighting factor and the X-domain weighting factor to generate a weighted input signal of a demapper and performing linear demapping of the weighted input signal in the demapper. There is also disclosed an apparatus for demapping dual carrier modulated COFDM signals and a receiver comprising such an apparatus.

Abstract: A receiver may comprise a complex mixer for converting the modulated signal to a complex modulated signal comprising a first in-phase component and a first quadrature component. The receiver may further comprise a digital demodulator. The digital demodulator may comprise at least one processor circuit programmed for applying a phase differencer for generating an output function in terms of a phase difference of the complex modulated signal. Applying the phase differencer may comprise converting the first in-phase component to a function of a phase difference of the first in-phase component expressed in digital time, and converting the first quadrature component to a function of the phase difference of the first quadrature component expressed in digital time. The at least one processor circuit of the digital demodulator may also be programmed for applying a four quadrant inverse tangent to the output function to generate the information signal.

Abstract: A delay-line demodulator for demodulating a differential quadrature phase shift keying (DQPSK) signal is provided. The demodulator includes two Mach-Zehnder interferometers individually comprising two waveguides having different lengths therebetween and through which a light signal branched from the DQPSK signal propagates, respectively. A phase of the light signal propagating at one of the waveguides is delayed as compared to a phase of the light signal propagating at another one of the waveguides, wherein a divergence amount of polarization is adjusted by driving sets of heaters that are facing each other and sandwiching a half wavelength plate therebetween.

Abstract: A wireless communication apparatus receives an quadrature modulated signal, generate a local signal having a frequency different from a center frequency of the quadrature modulated signal, performs quadrature demodulation on the quadrature modulated signal by using the local signal, to obtain an I channel signal and a Q channel signal, performs Fourier transform on the I channel signal and the Q channel signal, to obtain signals in a frequency domain, and calculates a first correction coefficient for correcting phase distortion and amplitude distortion caused by the quadrature demodulation by using pairs of signals among the signals, each of the pairs are located at symmetrical frequency positions with respect to the frequency of the local signal.

Abstract: A reception quality notifying method improves upstream-line throughput by reducing the data amount of reception quality data of downstream multicarrier signals to be transmitted in the upstream line. A low-power consumption base station apparatus and a wireless communication terminal apparatus may employ the reception quality notifying method. When a wireless communication terminal apparatus receives a downstream multicarrier signal and then notifies a base station apparatus of a subcarrier having a desirable reception quality for the downstream multicarrier signal, the wireless communication terminal apparatus produces reception quality data of a plurality of formats, then selects, from among the produced reception quality data, one having the lowest data mount. The selected reception quality data is transmitted to the base station apparatus by use of an upstream multicarrier signal subcarrier designated by the base station apparatus.

Abstract: Methods and apparatus to compensate for I/Q mismatch in quadrature receivers are disclosed. An example apparatus disclosed herein comprises a correction engine using first filter coefficients to compensate for I/Q mismatch present in a received quadrature signal; an adaptation engine to adapt second filter coefficients based on I/Q mismatch present in the received quadrature signal; and coefficient controller to occasionally adjust the first filter coefficients based on the second filter coefficients.

Abstract: Various embodiments are described herein for a system and method of detecting Automatic Identification System (AIS) signals in space and decoding these signals. In one aspect, a system for performing this function is described which includes a receiver configured to receive the plurality of AIS signals and pre-process the plurality of AIS signals to produce digital input data, and a processing unit configured to process the digital input data to identify one or more candidate AIS message signals based on Doppler offsets associated with the digital input data, determine corresponding Doppler offset estimates and time estimates of the one or more candidate AIS message signals, decode the one or more candidate AIS message signals to obtain corresponding message segments and validate the decoded message segments for proper AIS formatting.

Abstract: A system comprises a correlation module that receives modulated signals from R antennas, that correlates each of the modulated signals with Y preamble sequences, and that generates Y correlation values for each of the R antennas, where R and Y are integers greater than or equal to 1. A control module generates correlation sums by adding each of the Y correlation values for one of the R antennas to corresponding ones of the Y correlation values for others of the R antennas, that selects a largest correlation sum from the correlation sums, and that detects one of the preamble sequences in the modulated signals when a magnitude of the largest correlation sum is greater than or equal to a first predetermined threshold.

Abstract: Provided are a frequency modulation/demodulation apparatus using a frequency selective baseband and a transmitting/receiving apparatus using the same. In a frequency selective baseband transmission technique or an FS-CDMA technique, a transmission rate is controlled according to communication channel environment, spread code groups are repeatedly selected in a receiving side so as to obtain a frequency diversity gain. Accordingly, it is possible to reduce interference between users. In addition, even in a case where strong interference induced from electronic exists, it is possible to implement low-power, stable human-body communication and to ensure a communication quality.

Abstract: An approach is provided for clock-pulse synchronization between an amplitude-modulated or phase-modulated received signal and a transmitted signal by estimating the timing offset between the received signal and the transmitted signal by maximum-likelihood estimation, wherein the maximum-likelihood estimation is realized through a pre-filtering dependent upon the transmission characteristic, a subsequent nonlinear signal-processing function and an averaging filtering. The received signal is an offset quadrature-phase-modulated received signal, and the nonlinear signal-processing function maintains the alternating components in the spectrum of the pre-filtered offset quadrature-phase-modulated received signal.

Abstract: A communication system and method of communicating signals to a plurality of different types of receivers is provided. At least one transmitter transmits hierarchically modulated high priority and low priority signals as a single frequency network. At least one satellite re-transmits the high priority signal in a first circularly polarized direction and the low priority signal in a second circularly polarized direction. At least one of a first receiver having a single antenna is configured to receive the high priority signal in the first circularly polarized direction and switched to receive the low priority signal in the second circularly polarized direction, and a second receiver having a first antenna is configured to receive the high priority signal in the first circularly polarized direction, and a second antenna is configured to receive the low priority signal in the second circularly polarized direction substantially simultaneously.

Abstract: A solution for signal detection in a radio receiver receiving multicarrier signals is disclosed. According to the provided solution, the radio receiver receives a radio signal and converts the received radio signal into digital samples. Since a desired signal being detected occupies only a portion of subcarriers of a signal the radio receiver is configured to receive, the received signal is heavily oversampled. A detection procedure may be simplified by utilizing this oversampling. A relation between the known total bandwidth of the desired signal and the total bandwidth of the received radio signal may be calculated, and utilized in the actual signal detection. The signal detection is based on sliding correlation in which the samples of the received signal are correlated with a reference signal with different phase shifts between the two signals. As the result of the correlation, the received signal is determined to be either the desired signal or noise.

Abstract: A method and a device for determining, in a signal, a value of the frequency of a carrier and a value of the frequency of symbols carried by the carrier. A band of the signal is analyzed at three points and the relations between the powers at these points enable determining values of the carrier frequency and of the symbol frequency.

Abstract: An apparatus and a method for cancelling an interference of each of a plurality of received signals are provided. The apparatus comprises an estimation module, an ordering module, a selection module, an equalizer, and a cancellation module. The estimation module estimates a plurality of estimated channels according to a first predetermined number of pilot-tones. The ordering module decides a decision order for processing. The selection module selects a second predetermined number of the received signals as the second predetermined number of processing signals. The equalizer estimates the estimated values, wherein each of the estimated values corresponds to a processing signal. The decision module decides a decided value for each of the estimated values. The cancellation module cancels the interference for each of the processing signals according to the corresponding decided value and the corresponding channel.

Abstract: A method and apparatus is disclosed to compensate for an in-phase/quadrature phase (I/Q) imbalance in a communications receiver. The communications receiver may utilize information gained from observing one or more observational interferers to adjust one or more sequence parameters, such as gain and/or phase to provide some examples. The one or more observational interferers including one or more images outside of a desired frequency band of interest. The communications receiver provides one or more sequence parameter values to allow for real-time adjustment of the sequence parameters to compensate for the I/Q imbalances.

Abstract: A D-PSK demodulator utilizes a two-layer coherent approach to estimate the phase shift of adjacent symbols. There is generated a probability set of each received symbol being one of possible constellation values. There is also generated a probability set of each of possible phase difference between two adjacent symbols. This probability set is then converted into soft bit information according to specific mathematical operation.

Abstract: Disclosed are hybrid heterodyne transmitters and receivers for use in communications systems, or other systems, and the corresponding methods for hybrid heterodyne transmitting and receiving. A heterodyne receiver for converting a continuous time modulated signal to a discrete time digital baseband signal includes a sigma-delta modulator. The sigma-delta modulator is a sigma-delta analog-to-digital converter constructed and arranged to receive a modulated signal at an RF carrier frequency and provide a quantized output at a first intermediate frequency. The heterodyne receiver may also include a digital mixer constructed and arranged to receive a data stream quantized by the sigma-delta analog-to-digital converter and receive a signal at a second mixing frequency. The digital mixer then provides digital signals representative of a baseband signal suitable for digital signal processing.

Abstract: System and method for signaling control information in a multi-carrier communications system to transmit data. A preferred embodiment comprises demodulating a first carrier that is used for transmitting a control channel transmission, determining a second carrier that is used for transmitting a data channel transmission based upon the demodulated control channel transmission, and demodulating the second carrier to obtain the data channel transmission. Additionally, designs for multi-carrier receivers are provided.

Abstract: A timestamp-based clock synchronization technique is employed for CES in packet networks. The technique is based on a double exponential filtering technique and a linear process model. The linear process model is used to describe the behavior of clock synchronization errors between a transmitter and a receiver. The technique is particularly suitable for clock synchronization in networks where the transmitter and receiver are not driven from a common timing reference but the receiver requires timing reference traceable to the transmitter clock.

Abstract: A system and method communicates and generates a Coded Orthogonal Frequency Division Multiplexed (COFDM) communications signal as a plurality of subcarriers. Selected subcarriers are turned ON and OFF while also frequency hopping and spreading the selected ON subcarriers over the frequency domain based on a fixed or variable sample rate to reduce average power for enhanced Low Probability of Interception/Low Probability of Detection (LPI/LPD) and also allow for more transmit power within a spectral mask.

Abstract: The invention provides a method for implementing demodulation of quadrature layered modulation (QLM) communications using maximum likelihood (ML) demodulation algorithms which limit the demodulation loss. QLM layers communications channels over the same bsndwidth and with a differentiating parameter for each layer which enables a demodulation algorithm to recover the data symbols in each layer. QLM supports higher data rates than allowed by the Shannon bound. QLM demodulation algorithms are trellis symbol algorithms, trellis bit algorithms, ML algorithms, and other equivalent algorithms. Trellis algorithms rapidly increase in complexity with the number of layers of communications and with the order of the modulation. ML algorithms are less complex but have demodulation losses which rapidly increase with the number of data symbols. ML demodulation architectures disclosed in this invention limit these losses and are suitable to implement QLM for higher order modulations and for more layers of communications.

Abstract: A method and system for digital baseband receiver with digital RF/IF/VLIF support in GSM/GPRS/EDGE compliant handsets. The method may comprise receiving an input signal which may be a digital RF signal, IF or VLIF signals, and the input signal may comprise of I and Q components. The serial digital RF signal may be converted to a parallel digital formatted signal, the latter of which may be transferred to an input of a multiplexer. The received IF signal or VLIF signal may be filtered and transferred to the input of the DU which may convert the VLIF signal to a baseband signal by processing the VLIF signal with a CORDIC algorithm. The DU may bypass processing the IF signal. The output of the DU may be transferred to the input of the multiplexer, such that the multiplexer may select the parallel digital formatted signal or the output of the DU.

Abstract: A signal receiving apparatus includes: an acquisition section configured to acquire an Orthogonal Frequency Division Multiplexing signal resulting from combination of a plurality of signals transmitted by a plurality of signal transmitting apparatus by adoption of an Orthogonal Frequency Division Multiplexing method; and a demodulation section configured to carry out partial processing of processing to demodulate the Orthogonal Frequency Division Multiplexing signal acquired by the acquisition section by making use of either first pilot signals or second pilot signals where the first pilot signals are pilot signals extracted from the Orthogonal Frequency Division Multiplexing signal acquired by the acquisition section as signals having the same phase for all the signal transmitting apparatus, and the second pilot signals are pilot signals extracted from the Orthogonal Frequency Division Multiplexing signal acquired by the acquisition section as signals having different phases depending on the signal transmitt

Abstract: The invention relates to methods for adaptive clock reconstruction and decoding in audio frequency. The method includes the steps of: receiving a modulated signal, wherein the modulated signal is modulated by RC-FSK (Return to Carrier Frequency Shifting Keying); performing a spectrum analysis to the modulated signal to obtain a plurality of frequency envelopes; storing the frequency envelopes; searching the peak values of the frequency envelopes and the time points corresponding to the peak values to modify an estimated period; and generating a clock period for the RC-FSK demodulation and a clock phase for the RC-FSK demodulation according to the estimated period.

Abstract: A radio receiving apparatus wherein the interference can be minimized and the power and bands can be effectively used in the process of receiving a signal comprising a combination of an impulse signal and an OFDM signal. In this apparatus, a transmission path equalizing part (205) performs a transmission path equalizing process of a signal comprising a combination of an OFDM signal and an impulse signal of UWB-IR system, and a signal separating part (208) uses a constant (C) to clip the amplitude level for a signal (Y1) demodulated as the OFDM signal, and substantially clips only the signal components of the impulse signal. Further, only when a signal (Y2) demodulated as the impulse signal exhibits an amplitude level greater than the constant (C), it is outputted, while most of the signal power of the combined OFDM signal is removed.

Abstract: A composite baseband signal includes a desired signal component modulated according to a first modulation scheme and an interfering signal component modulated according to a second modulation scheme. Information is recovered from the composite signal by applying a phase rotation associated with the second modulation scheme to the composite signal to generate a rotated signal. Based on the rotated signal, a channel model associated with the desired signal component and interference cancelling filter coefficients associated with the interfering signal component are generated. The rotated signal is filtered according to the interference cancelling filter coefficients to suppress the interfering signal component from the rotated signal. The filtered signal is equalized based on branch metrics derived from the channel model and symbol hypotheses rotated in accordance with a difference in phase rotations associated with the first and second modulations to recover information from the desired signal component.

Abstract: A communication apparatus capable of improving the spectrum usage rate of a system, especially, the spectrum usage rate in connection with both a fast fading and a channel estimation error as compared with the conventional sub-band adaptive method, while reducing the degree of the difficulty in achieving the adaptation, and further reducing the feedback overhead. In this apparatus, a sub-band group AMC parameter selecting part (318) selects an AMC parameter of each sub-band. An adaptive reception control part (503) must control an adaptive demodulating/decoding part (311), while controlling a parallel/serial converter (312) in a stage preceding the adaptive demodulation and decoding processes, and combining received symbols in the same sub-band group for demodulation and decoding.

Abstract: A demodulator is provided for demodulating a phase-modulated data signal. The demodulator includes a phase frequency detector to output a voltage representing a phase difference between a received phase-modulated data signal and a reference clock signal. The voltage is input to first and second phase change detectors, which are provided to measure the phase difference of the phase-modulated data signal during first and second time periods, respectively.

Abstract: A carrier frequency in a filtered received M-ary phase-shift keyed (MPSK) modulated signal having in-phase and quadrature components is detected by processing the filtered received signal to remove modulation components and thereby generate a test signal at the carrier frequency; processing the test signal to provide an amplitude spectrum of samples at different test frequencies; and processing the amplitude spectrum to detect the carrier frequency in accordance with the test frequency at which there is a test statistic of the highest magnitude. The magnitude of the test statistic is determined by processing a signal statistic in relation to a noise statistic. The signal statistic is the amplitude of the largest-amplitude sample. The filtered received signal is processed to provide approximate values of the modulus of the received signal and the phase of the received signal; and the approximate modulus and phase values are processed to generate the test signal.

Abstract: A method and an arrangement for processing a received signal which comprises phase-shift modulated or amplitude-quadrature modulated part-signals which are transmitted in a plurality of different frequency bands, wherein the received signal is processed in a plurality of stages in succession, by multiplying all the input signals to each of the stages by two mutually orthogonal signals in each case to form two intermediate signals in each case, wherein the intermediate signals from one stage in each case act as the input signals to whichever is the succeeding stage in the particular case and the received signal acts as the input signal to the first stage, and wherein an in-phase and/or an quadrature component of the individual part-signals in the different frequency bands are determined from the intermediate signals from the last stage. Parallel, simultaneous reception of a plurality of frequency bands can be implemented relatively easily in this way.

Abstract: A method of determining a metric for evaluating an error probability of a data frame includes receiving, at a radio receiving device, the data frame encoded according to a coding method and transmitted through a radio communication channel by a radio transmitting device. The data frame includes a plurality of symbols. The method also includes performing a channel equalization of the data frame received at the radio receiving device to produce a channel equalized data frame, performing a symbol de-mapping of symbols in the channel equalized data frame to produce a de-mapped data frame, obtaining soft bits based on the de-mapped data frame and characteristics of the coding method, and calculating the metric from at least one moment, having an order strictly greater than one, of quantities that characterize an equivalent communication channel for the soft bits.

Abstract: A radio receiver includes a processing unit that may generate a respective phase value corresponding to each of a plurality of digital samples of a received complex frequency modulation (FM) signal. The receiver also includes an impulse unit that may detect whether a linear combination of a phase value of a current sample and a phase value of one or more previous samples will produce an impulse at an output of an FM demodulator. If the impulse unit detects that an impulse will be produced at the output, the impulse unit may replace the output of the FM discriminator with a predetermined value.

Abstract: A simplified architecture is disclosed for use in wireless receiver applications, particularly for ADC conversion of received in-phase I and quadrature Q signals. Circuit area is substantially reduced by sharing a single ADC to convert both signals, switching the ADC input alternately between the i and q signals. In an embodiment, the ADC is clocked at an increased sample rate, and the digital output signals are aligned to compensate for the phase difference resulting from the implementation of a single ADC.

Abstract: A method and apparatus are provided for measuring channel quality over which has been transmitted a sequence of symbols produced by encoding and constellation mapping a source data element sequence. The method includes receiving a sequence of received symbols over the channel whose quality is to be measured. The sequence of received symbols is de-mapped based on a first channel quality indicator previously transmitted to a transmitter of the sequence of symbols. The method also includes decoding the de-mapped symbols to produce a decoded output sequence. In some embodiments, the decoding may be based on the first channel quality indicator. The method also includes re-encoding the decoded output sequence to produce a re-encoded output sequence. The method also includes correlating the de-mapped symbols with the re-encoded output sequence to produce a second channel quality indicator.

Abstract: A compensator unit compensates frequency-dependent imbalance between a sampled in-phase and a sampled quadrature phase signal. The compensator unit includes a delay channel (381) and a filter channel (382). The delay channel (381) delays an intermediate signal x(t), which is obtained by superposition of the sampled in-phase and quadrature phase signals, by an integer multiple greater than zero. The filter channel (382) includes a filter (320) with a complex conjugated block (321) and with variable filter coefficients determined on base of autocorrelation function values of the intermediate signal x(t). The filter coefficients are determined such that the complementary autocorrelation of a compensator output signal y(t) is minimized for the filter span.

Abstract: A reception quality estimating apparatus, a wireless communication system and a reception quality estimating method wherein the communication qualities in a case where different communication schemes are used to have communication can be artificially estimated without switching the communication schemes to be used for the communication. A wireless communication apparatus (100) comprises a reception processing part (110), an artificially decoded error estimating part (120), and an upper-order layer processing part (130). An orthogonal vector data sequence (152), which is generated by a demodulating part (111) from a received signal (150), for each symbol in the current modulation scheme is used to artificially generate a likelihood metric value (155) obtained in a case of using a second communication scheme, which has a larger number of modulation multi-values than the current communication scheme, to perform a signal point arrangement.

Abstract: The present invention relates to a method for transmitting data in the form of at least one pulse sequence Tsgk (for k=1 to K). The method according to the invention includes at least one symbol decoding step in the course of which at least one modulation value Pwk representative of an amount of power carried by each pulse sequence Tsgk is computed and compared to at least one predetermined threshold value Thvk, which will be computed beforehand by equating a first and a second probability density function representing a likelihood for the transmitted signal to carry a first symbol and a likelihood for the transmitted signal to carry a second symbol, respectively. The method according to the invention enables to limit the processing time and power needed for performing the demodulation of a power-modulated UWB signal.

Abstract: A receiver comprises a demodulator to estimate channel impulse response and timing synchronization information for the received signal and to select a modulation technique for demodulating the received signal; and a channel decoder to produce a binary sequence from the received signal demodulated according to the selected modulation technique; wherein the demodulator: demodulates the received signal according to a first modulation technique and a second modulation technique to produce a first demodulated signal and a second demodulated signal, respectively; calculates a minimum distance between a first reconstructed signal including the training sequence and the first demodulated signal to estimate the channel impulse response and timing synchronization information; calculates a minimum distance between a second reconstructed signal including the training sequence and the second demodulated signal to estimate the channel impulse response and timing synchronization information; compares the minimum distance co