Abstract: Systems and methods for estimating channel response in the presence of interference. Interference and/or noise present on received training symbols is estimated. Based on the measured noise and/or interference, a weighting among training symbols is developed. Channel response is then estimated based on a weighted least squares procedure.

Abstract: A method for measuring with a maximum error E the phase of a substantially sinusoidal signal, of angular frequency ?=2?/T, sampled with a sampling period T/r, in which the phase is calculated as the time at which a straight line crossing two consecutive samples located on either side of a median value of the signal reaches said value, including the step of selecting number r from a range included between a value r0 and a value equal to from two to three times value r0, such that: E ? max t ? [ - T r0 , 0 ] ? [ t - T r0 · round ? ( G · sin ? ? ? ? ? t ) round ? ( sin ? [ G · ? · t + 2 ? ? r0 ] ) - round ? ( G · sin ? ? ? ? ? t ) ] round(x) being the integer closest to a real number x and G being equal to 2iG1, where i is the number of bits on which are coded the samples and where G1 is a term of correction of the amplitude of the sampled signal.

Abstract: In a method and device for recovering the high frequency content of a wideband signal previously down-sampled, and for injecting this high frequency content in an over-sampled synthesized version of the wideband signal to produce a fill-spectrum synthesized wideband signal, a random noise generator produces a noise sequence having a given spectrum. A spectral shaping unit spectrally shapes the noise sequence in relation to linear prediction filter coefficients related to the down-sampled wideband signal. A signal injection circuit finally injects the spectrally-shaped noise sequence in the over-sampled synthesized signal version to thereby produce the full-spectrum synthesized wideband signal.

Abstract: A multi-tone modulation method is provided which reduces a peak average power ratio. The method involves defining a respective signal constellation for each center frequencies having redundant mappings for each set of input elements, and then selecting a particular permutation of mappings having a reduced peak power for the multi-tone signal. A method of shaping is also employed in which a hierarchy of blocks are defined, each layer having fewer blocks than each previous layer. The hierarchy is used to select a particular subset of an expanded constellation.

Abstract: An equalizer includes at least two first mutually interfering equalizer sections, and at least two second interference-correcting equalizer sections, arranged in series. Each of the second equalizer sections corresponds with one first equalizer section, such that although each corresponding equalizer section has the same center frequency, the second equalizer sections have an equalization response opposite the interference effect, and the gain of the corresponding second equalizer section at the respective common center frequency contains the negative gain of at least one first equalizer section adjacent to the corresponding first equalizer section at the center frequency of the corresponding first equalizer section.

Abstract: A signal processing apparatus preferably suitable for implementation as an integrated circuit, that is arranged and constructed to be shared for processing a plurality of signals without interference between the signals and method thereof, the signal processing apparatus comprising: an input multiplexer for sequentially selecting from among the plurality of signals to provide a sequence of selected signals; a processing unit for processing the sequence of selected signals to provide a sequence of processed signals, the processing unit having an input coupled to the input multiplexer and a delay stage including a plurality of series coupled delay elements with one delay element corresponding to each of the plurality of signals; and an output de-multiplexer for sequentially selecting from the sequence of processed signals to provide a plurality of processed signals corresponding one to one with the plurality of signals.

Abstract: A method of controlling a communication device that is operable to transmit digital data over a plurality of frequency channels. The method includes selecting an initial transmission power and a corresponding data rate for each channel. The method also includes identifying in a first channel a first ratio of a first decrement in transmission power to a first data rate decrement that is greater than a second ratio of a second decrement in transmission power to a second data rate decrement. Then, the initial transmission power allocation of the first channel is reduced by the first decrement. The method also includes reallocating the decremented initial transmission power of the first channel to one or more other channels.

Abstract: A method and system for reducing the power to average ratio (PAR) at the transmitter after the up sampling and interpolation filter. In the time domain, Side Tone Packets Injection (STPI) system and method detects the optimal peaks that will result in having a low PAR at a sampling rate of T/K and combines an optimal binary and a PAR-lowering sequence and an upsampled, interpolated original discrete time signal at the scale of one extended symbol for multi-carrier modulation and at the scale M of symbols for single-carrier modulation. STPI does not require peaks search and processing at the scale of many time samples, does not require iterative Fast Fourier Transform (FFT) and Inverse Fast Fourier Transform (IFFT) processing thus, allowing the receiver not to perform extra demodulation.

Abstract: A method and system for encoding and decoding an input signal in relation to the most perceptually relevant aspects of the input signal. A two-dimensional (2D) transform is applied to the input signal to produce a magnitude matrix and a phase matrix that can be inverse quantized by a decoder. A first column of coefficients of the magnitude matrix represents a mean spectral density (MSD) function of the input signal. Relevant aspects of the MSD function are encoded at a beginning of a data packet. The MSD function is also processed through a core perception model to determine bit allocation. The matrices are then quantized and priority ordered into a data packet, with the least perceptually relevant information at the end of the packet so that it may be ignored or truncated for scalability to the channel data rate capacity.

Abstract: A method and apparatus are provided which detects distortion in a received FM signal caused by amplitude modulating and phase transition of two combined FM signals. A method corrects and modifies the distortion by detecting a distorted sample, replacing the distorted sample with an appropriate sample, and applying a smoothing process to the sample.

Abstract: Over a channel, a signal including a desired portion associated with a desired channel and an undesired portion mixed with said desired portion may be received. Based on prior knowledge and/or empirical estimation of the desired channel and an empirical estimate of the signal cross-covariance, the desired portion from the received signal may be recovered by adaptively equalizing the channel. In one embodiment, a receiver, such as a mobile device (e.g., a cellular phone) includes a processor operably coupled to a communication interface including at least two antennas to receive the signal. The receiver may further include a MODEM that may be operably coupled to the processor, that includes an adaptive equalizer capable of detecting the signal in the presence of co-channel interference from several independent sources, inter-symbol interference and fading, for recovering the desired portion in a cellular environment with time division multiple access (TDMA) to enable digital transmission of the signal.

Abstract: A frequency synchronization apparatus and method for OFDM systems. The frequency synchronization apparatus is comprised of a digital mixer, a first synchronizer and a second synchronizer. The digital mixer acquires a baseband signal by means of a local frequency and adjusts the local frequency in response to an integer frequency offset and a fractional frequency offset. The first synchronizer takes a sequence of received samples derived from the baseband signal in a time domain to estimate the fractional frequency offset. The fractional frequency offset is fed back to the digital mixer. After that, the second synchronizer takes a sequence of demodulated symbols derived from the baseband signal in a frequency domain. The second synchronizer yields the integer frequency offset through a coarse search stage and a fine search stage. Then, the integer frequency offset is fed back to the digital mixer.

Abstract: A high data transmitter and a high data receiver that uses both Walsh codes and quasi orthogonal functions in spreading and despreading transmitted and received signals.

Abstract: A performance indicator for wireless digital signal reception is disclosed. In particular, a method for indicating the reception quality of a wireless digital signal at an electronic device is disclosed. The method includes a series of steps, starting with a first step of receiving the wireless digital signal at the electronic device. In the next step, the wireless signal is demodulated. Then, an error rate associated with the digital data portion of the wireless signal is determined. In the next step, a quality level of reception of the wireless signal is indicated. Specifically, the quality level of reception is directly proportional to the error rate of the digital data portion of the signal.

Abstract: Disclosed is provided a method and apparatus for mapping a stream of bits output from an encoder to a stream of bits for 2m-ary modulation. The method and apparatus divides the stream of bits from the encoder into a first period and a second period. The first period includes bits with higher priority in the stream of the bits output from the encoder, and the second period includes bits with lower priority. The method and apparatus maps the bits existing in the first period to bit positions with higher reliability in a stream of m bits representing each of the bits for 2m-ary modulation, and maps the bits existing in the second period to bit positions with lower reliability in the stream of m bits.

Abstract: A system and a method for multiplying data throughput in a SCSI bus includes identifying multiple frequencies within a bandwidth of a SCSI bus. A binary value is assigned to each one of the multiple frequencies. One of the multiple frequencies is selected. The assigned binary value of the selected frequency corresponds to a set of bits to be transmitted during a first sampling cycle. The selected frequency is transmitted on the SCSI bus during the first sampling cycle.

Abstract: Disclosed is a method and apparatus for synchronizing data. In one embodiment, the apparatus includes a first communication link for transmitting first data and a second communication link for transmitting second data. A circuit coupled to the first and second communication links. The circuit is configured to receive the first and second data. The circuit is configured to synchronously output the first and second data when the first and second data are received by the circuit out of synchronization.

Abstract: A data channel includes a data detector that approximates both inter-symbol-interference (ISI) and random timing perturbations using a single finite-state hidden Markov model. The ISI is approximated by a finite impulse response and the timing perturbations are approximated by a first order random walk. The data signal, which is subject to inter-symbol interference and timing perturbations, is sampled periodically over a succession of time epochs without regard to timing perturbations. Timing perturbation values and data states are then assigned for each epoch, and each timing perturbation value is paired with each data state to arrive at a set of composite states. Probabilities are then assigned between composite states in successive epochs to arrive at the most probable composite state sequence corresponding to the sequence of detected data values from the sampled data. A Viterbi algorithm is then applied to find the maximum likelihood sequence of composite states.

Abstract: A data modulation method and a data modulation device and a communication device are disclosed. The present invention relates to the synchronization and training preamble. The reference symbol optimized in order to contain the structure of “IA-A-IA-A-A-IA-A-IA-IA” is allocated to sub-carriers of the OFDM symbol. More specifically, by designing the structure of the preamble of the time domain, distinction from the other communication system can be certainly conducted holding the correctness of the clock synchronization. Also, we have adopted the series having low peak average ratio and dynamic range of sync symbol using the OFDM. Since the generation and the detection processings can be conducted in utilizing the generation device and the detection device of the sync preamble used in the convention system, this system has an advantage in increasing the common use of the LSI chip. We have made the sync series divided into 2 parts A and B before to one B region and made this to have simple construction.

Abstract: A register controlled delay locked loop (DLL) includes a clock divider, a shift controller, a delay unit and a delay model to synchronize an external clock signal with an internal clock. The register controlled DLL further includes a reset signal generator to generate a reset signal used to initialize the delay locked loop (DLL), a phase comparator to initialize a phase comparison signal in which the phase of a feedback clock signal delayed by a reference clock signal and the delay model is compared and outputted into a predetermined signal by using a comparison enable signal having an inverse phase to that of the reset signal, and a shift register to block an electric current running on a first latch of a plurality of latches with the reset signal during the initialization.