Abstract: Apparatus and methods of ultra-wideband (UWB) communication are provided. In one embodiment, an ultra-wideband receiver receives a serial data stream comprising a plurality of ultra-wideband pulses. A serial to parallel converter then converts the serial data stream into a plurality of parallel data streams, which are then matched. A combiner then combines the data streams, which are then fed to an equalizer that includes a hard decision element, a past decision element and a future decision element. This Abstract is provided for the sole purpose of complying with the Abstract requirement rules that allow a reader to quickly ascertain the subject matter of the disclosure contained herein. This Abstract is submitted with the explicit understanding that it will not be used to interpret or to limit the scope or the meaning of the claims.

Abstract: A method and apparatus for data communication in a variety of communication systems using spread spectrum techniques and multilevel sequences in which distinct multilevel sequences used contain binary subsequences that interfere constructively such that synchronous cross-correlation values add constructively. By adding two subsequences from different sets, it is ensured that neither subsequence belongs to the same set. This, in combination with use of correlators, reduces complexity and facilitates increasing the order of a modulation scheme, thus enhancing the bandwidth efficiency.

Abstract: A communication channel delivers a binary signal representing a data sequence by a pattern of high and low logic levels (symbols) from a transmitter to a receiver. The communication channel low-pass filters the transmitter output signal (VX) so that the signal (VR) arriving at the receiver is a distorted version of the transmitted signal. A receiver processes the received signal to produce an output first data signal (Z) representing the sequence of symbols conveyed by the transmitted signal. The receiver filters the received signal with a transfer function controlled by a control signal to produce a compensated signal (X). The receiver responds to trailing edges of the sampling clock signal by driving the first data signal to a succession of first states, wherein each first state corresponds to a separate leading edge of the sampling clock signal and represents a magnitude of the compensated signal on occurrence of the first state's corresponding sampling clock signal leading edge.

Abstract: A system for mitigating noise associated with information communication includes means for determining when a first set of information is transmitted by a transmitter. The system includes a receiver for receiving a second set of information in response to the first set of information. The system also includes control means for temporarily suspending at least one process when the determining means determines that the first set of information is being transmitted and for continuing the at least one process after the second set of information has been received by the receiver. The at least one process produces noise that interferes with an integrity of the second set of information received by the receiver.

Abstract: A method and apparatus for reducing an amount of bits of data at at least two stages of data transfer in a communications reception data path between a rake receiver and a channel decoder.

Abstract: A system includes first unit, a processor and a transmitter. The processor is located in the first unit to generate data to be communicated to a second unit that is physically separated from the first unit. The transmitter includes an antenna, a first circuit and a push-pull amplifier. The first circuit generates signals that are indicative of the data, and the push-pull amplifier drives the antenna with a signal that is indicative of the data in response to the signals generated by the first circuit. The amplifier also establishes an output power from the amplifier to the antenna to less than about one hundred milliwatts.

Abstract: A fast-tracking discrimination approach provides rapid acquisition useful for direct-sequence spread spectrum applications. In one example embodiment, the present invention is directed to a communication system receiver that operates a linearly normalizing discrimination process on a signal modulated by a waveform having a bit rate defined in terms of a bit-pulse duration (chip). For at least one reference code, correlation results are obtained from several timing offsets of the signal, where each timing offset is separated by a fixed chip offset. Using at least three consecutive ones of these correlation results, assuming that the correlation energy of band-limited signals is approximately quadratic, an accurate phase error is obtained for synchronizing the received signal.

Abstract: Disclosed is a predistorter for preliminarily compensating a distortion caused in a circuit comprising a modulator, a variable gain amplifier, and a non-linear amplifier, the predistorter comprising: an amplitude detector for detecting an amplitude of an input signal; a gain detector for detecting a gain of the variable gain amplifier; a first multiplier for multiplying the amplitude of the input signal with the gain of the variable gain to output a product therebetween; a generator for generating a predistortion function corresponding to the product; and a second multiplier for multiplying the input signal with the predistortion function to output a product therebetween to the modulator.

Abstract: Following arrangement of an adaptive equalizer with a direct filter structure according to the least mean square error architecture, look ahead conversion of modifying a tap coefficient of the next cycle utilizing the tap coefficient of a predetermined preceding cycle is carried out and then a retiming process of adjusting the timing of tap coefficients and signals is carried out to arrange delay elements, whereby a transposition filter is realized. A high-speed adaptive equalizer is provided that can have the critical path reduced without increasing the hardware amount and that is superior in expansionability.

Abstract: In a matched filter, a spread data path unit holds inputted spread data, a multiplier unit multiplies an output of the spread data path unit by a spreading replica code, and an adder unit adds results of the multiplication and outputs an added result. The spread data path unit comprises a first selector being able to selectively output the spread data, a plurality of sub spread data path units each having a plurality of latch circuits temporarily holding the spread data from the first selector, and a second selector being able to selectively output outputs from the sub spread data path units, whereby a circuit scale of the spread data path unit is decreased.

Abstract: To estimate the channel characteristics on the basis of the time differences of the sample points, and to reduce memory capacity and processing steps required for the estimation. The first adder sums up detected pilot signals slot by slot, while the second adder sums up ((sample number n)×pilot signals) slot by slot. The output from the first adder multiplied by (4N−2)/(N(N+1)) and the output from the second adder multiplied by (−6)/(N(N+1)) are added in the third adder. The output from the first adder multiplied by (−6)/(N(N+1)) and the output from the second adder multiplied by (12)/(N(N−1)(N+1)) are added in the forth adder. The output from the forth adder is filtered by LPF to obtain output b (k) which is an inclination value of the channel characteristics of a slot, while the output from the third adder is compensated by FLT to obtain a (k) which is a bias value of the channel characteristics.

Abstract: The invention aims at adaptive array diversity reception of high convergence speed of combined weight by a simple signal processing, in a receiver by time division transmission system. Signals received by antennas (branches) are converted into base band signals in a receiving circuit, and are combined by a complex multiplying section and complex adder. The weight of the complex multiplying section is calculated by a weight calculating section. In the weight update algorithm of the weight calculating section, the step size in the least mean square is variable. That is, the initial value is set at a large value, and is decreased according to the lapse of time in each time slot, and is initialized at every change of time slot. As a result, by the same amount of calculation as in ordinary least mean square, the convergence speed of weight updating can be enhanced.

Abstract: A simplified method for sampling timing adjustment and frequency offset estimation in a TDMA cellular PCS environment using &pgr;/4 - shifted DQPSK comprises the steps of oversampling a received signal resulting from transmission of sequences of complex-valued symbols at a rate N times the symbol rate thereof so as to produce N sets of samples, comparing for each set of samples the differential phase angle between successively received complex-valued symbols, and determining which set of the N sets of samples has differential phase angles closest to ideal values to thereby obtain an optimal sampling timing. The differential phase angles are measured by multiplying a complex conjugate of a received complex-valued symbol and a succeeding symbol to produce a comparison vector having an angle equal to the differential phase angle between the received complex-valued symbol and the succeeding symbol. The differential phase angles are optionally rotated so that the angle thereof is between 0° and 90°.

Abstract: To improve a capacity of coherent detection of the spread spectrum (SS) signal, when interference and noise can not be neglected. Amplitude phase estimation unit outputs transmission line estimation value including fluctuations in the transmission lines, using known pilot signals of which transmission sequences are known. The pilot signal is extracted from the despread signal through despreading filter. Reliability measurement unit pursues a reliability value of transmission line estimation value. Interpolation unit generates vectors for compensating the phase, by deciding a method of interpolation on the basis of the reliability. Coherent detection unit compensates the amplitude and phase of information symbol to execute the coherent detection.

Abstract: A method is provided for transmitting control information in a digital audio broadcasting system. The method comprises the steps of transmitting a plurality of control bits in each of a plurality of control frames, wherein a first sequence of the control bits represents a transmission mode, and a second sequence of the control bits represents a control data synchronization word. The plurality of control bits can further include a third sequence of bits representative of an interleaver synchronization word. A method performed in a radio receiver for determining transmission mode and synchronization for a digital audio broadcasting signal is also provided. The method comprises the steps of receiving a plurality of interleaver frames containing digital information, wherein each of the interleaver frames includes a plurality of control frames.