Abstract: A communication device for W-CDMA signal transmission and reception includes a W-CDMA transmitter having at least one of a RAM and registers, a W-CDMA receiver having at least one of a RAM and registers, and a signal acquisition circuit. The communication device is software reconfigurable and further includes a digital circuit for phase unbalance precompensation in the W-CDMA transmitter. The digital circuit includes an input register holding a compensation angle and a section performing arithmetic calculations to acquire a change of an I, Q angle by the compensation angle. A method of operating a W-CDMA communication device includes the acts of configuring the device for a specific use, and performing at least one of transmitting, receiving and acquiring waveform signals. The configuring is preferably done by a processor.

Abstract: Method and apparatus for demodulation in a system having known frequency offsets. First and second signals from two users occupy substantially the same bandwidth and use substantially the same carrier frequency, while the relative frequencies of the signals on different transmit antennas associated with a base station are adjusted to have known, specific frequency offsets. These known frequency offsets are used at the receiver to aid in estimating any known frequency errors and to demodulate the multiple transmitted signals. In addition to being useful for demodulation, known frequency offsets can be assigned to each of a plurality of base stations to facilitate identification of a particular base station. The approach can be used for any type of time domain multiple access (TDMA) system, including Global System for Mobile (GSM), or for code division multiple access (CDMA) systems.

Abstract: Disclosed herein is a method and apparatus used to measure the number of time a multi-valued data signal transmitted from either a communication device of subsystem deviates across and into one or more bounded areas or zones as defined by an eye mask that is overlaid onto an eye diagram. The present invention employs an iterative process to accumulate and display mask violation that might result from a data signal transmitted from a target device or communications subsystem that deviates across the boundaries either above or below or into the center of the eye diagram. In addition, the present invention also has the ability to isolate particular threshold voltage-delay points along the boundaries above or below and around the perimeter of the mask polygon of the eye diagram where mask violations have occurred. This provides the ability to supply additional information and feedback about the behavior and performance of the targeted device or subsystem being tested.

Abstract: A splicer/transcoder 21 interfaces with a material archiver/server using a stream. The splicer/transcoder 21 interfaces with an editor and switcher 22 using a base band signal. In a predetermined region including at least an edit point, a transcoding process is performed. In an input stream, two programs to be edited have been multiplexed. The editor and switcher 22 receives base band signals Sa and Sb of which respective programs have been encoded. As with a conventional editing device, the editor and switcher 22 edits the base band signals and returns the edited result as a base band signal Sc to the splicer/transcoder 21. The splicer/transcoder 21 re-encodes the base band signal Sc into an output stream using codec information obtained in the decoding process.

Abstract: An embodiment of the present invention described in the specification and the drawings is an apparatus and method for code correlation in spread spectrum communication systems. The apparatus receives a data sequence, and offsets the data sequence with a fixed sub-chip delay. The data sequence and the offset data sequence are each despread with a locally generated code sequence. The despread results are summed and accumulated. The accumulated results may then be used to achieve a lower “miss” probability during code correlation.

Abstract: A multi-user detection method and device for a receiver in a multi-carrier code division multiple access telecommunication system, each communication to or from a user of the system being coded with a signature, the signal received by said receiver being decomposed into a first plurality of frequency components The frequency components are subjected to a first filtering matched to the respective signatures of a second plurality of users and to the common or respective responses of the transmission channels associated to said communications to or from said users. The output of the first filtering is subjected to a forward filtering followed by an estimation of the symbols transmitted to or by the users. The estimated symbols are subjected to a backward filtering, the output of said backward filtering being subtracted from the output of the forward filtering prior to the estimation.

Abstract: An improved method and apparatus for Viterbi Algorithm calculations for maximum likelihood sequence estimators in communication receivers is disclosed. The calculations for the maximum likelihood sequence estimator, in accordance with the invention, utilizes a variant of the Viterbi algorithm developed by Ungerboeck in which the associated branch metric calculations for the trellis require the computation of a set of branch metric parameters. An embodiment of the present invention provides for an improved recursive method and apparatus for calculation of the branch metric parameters that reduces the number of processor clock cycles required per state metric calculation. This enables real time computation of the branch metric parameters during execution of the Viterbi Algorithm.

Abstract: The invention relates to a method, a processing unit and a system for determining the correlation between samples of a received code modulated signal and samples of replica code sequences. In order to simplify and accelerate the process, it is proposed that the received samples and the replica samples are aligned to each other and that the positions of the samples in the received signal and in the replica code sequences are grouped, each group comprising all positions at which the composition of the values of the samples of all of the replica code sequences is similar. The values of the received samples which are associated to a respective group are combined separately for each group to obtain a respective preliminary result. Then, a correlation value is determined for each replica code sequence by combining the preliminary results obtained for all groups separately for each replica code sequence, taking into account the values of the samples of the replica sequences in the respective group.

Abstract: A method is provided for defining a pulse function shape for acting on a data stream for transmission in a telecommunication system which compensates for distortion by a component of the transmitter. The method comprises defining desired cost parameters (e.g., error functions for amplitude, BER, bandwidth, energy, AFC) and defining the shape of the pulse function in dependence of the desired cost parameters and the distortion to be compensated for. A pulse generator, modulator and communications device providing such a pulse function are also provided. Application in dual mode TDMA/CDMA system.

Abstract: In a wireless communication system, a method for estimating a transmitted signal is disclosed. A wireless signal is received that includes a pilot channel and at least one other channel. A transmitted signal is estimated using an equalizer and the received wireless signal. The equalizer includes a filter with a plurality of taps that are adapted through use of an adaptive algorithm that uses an estimated pilot estimated from the received wireless signal. The pilot channel is transmitted in the wireless signal that included the at least one other channel. The estimated pilot is extracted and provided to the adaptive algorithm.

Abstract: The invention relates to a method, a processing unit and a system for determining the correlation between consecutive sets of samples of a received, code modulated signal and replica samples. In order to reduce the computational load, the positions of samples in said replica code sequence are grouped, each of these positions and a predetermined number of respective subsequent positions forming a subgroup and each group comprising the respective first position of all subgroups with positions associated with a similar composition of consecutive replica samples. The method combines those values of samples of the first set of samples, which are associated by their position to a respective group, separately for each group to obtain a respective preliminary result. Determining a correlation value for each of the sets of samples then comprises combining the obtained preliminary results for all groups separately for each of the sets of samples.

Abstract: A complex symbol sequence (13), which is a product of an orthogonally detected complex demodulated symbol sequence (1) and a conjugate complex number of a known symbol sequence (2), is applied to phase rotating units (4a, 4b, 4c) which change the phase of the complex symbol sequence (13) based on frequency offsets (fa, fb, fc). N-symbol adders (5a, 5b, 5c) each add N symbol values supplied from the phase rotating units (4a, 4b, 4c), while M-power adders (6a, 6b, 6c) each calculate the power of a value supplied from the N-symbol adders (5a, 5b, 5c), and add the power M times. A frequency offset control unit (7) controls frequency offsets applied to the phase rotating units (4a, 4b, 4c) based on three power sums supplied from the M-power adders (6a, 6b, 6c), and delivers a power offset estimate (8).

Abstract: A hybrid data frame is presented for a time division multiple access frequency hopping communications system. The frame includes uplink and downlink subframes, and each subframe includes a plurality of frequency hops. First frequency hops in each subframe have at least one time slot, and the first hops follow default non-adaptive frequency hopping patterns, such that unsynchronized communicating units can synchronize with the communications system during the first hops using the predetermined default pattern. The second frequency hop also includes at least one time slot, and employs an adaptive frequency hopping pattern. Once a communicating unit is synchronized to the communications system via the first frequency hop, it can be assigned to a time slot within the second hop and adaptive frequency hopping interference avoidance techniques can be implemented.

Abstract: An apparatus and method provides efficient parallel processing for use with a single-bit sampler that provides single-bit samples at a high sample rate. A serial-to-parallel converter converts the single-bit samples into parallel single-bit samples at a reduced sample rate. A digital quadrature mix performs a frequency shift to the parallel single-bit samples and simultaneously performs a real-to-complex conversion of the parallel single-bit samples from the serial-to-parallel converter to provide parallel I and Q output values at an intermediate frequency. The serial-to-parallel converter has shift register stages that provide a memory for use in functional realization of a boxcar filter and decimation-by-two in the digital quadrature mix. The digital quadrature mix utilizes logic to route and invert the parallel single-bit samples resulting in the parallel I and Q single-bit output values. Additional filter and decimate stages may be used to process the parallel I and Q single-bit output values.

Abstract: A GPS receiver acquires carrier frequency and Gold code phase using short segments of a received GPS signal. In one embodiment, a 1-ms segment of the GPS signal is transformed to the frequency domain. This is multiplied by a frequency representation of the Gold code. The resulting product is converted to the time domain, and a peak is detected. The location of the peak corresponds to the code phase. If no peak is located, the carrier frequency is changed. Full- and half-bin steps in carrier frequency are considered. Processing gain is achieved by using longer segments of the input signal, for example 4 or 16 ms and integrating 1-ms segments. Considerations are provided for compensating for the effects of a transition, should it occur in the short segment of the GPS signal being processed. Integrations can be performed using non-coherent and coherent techniques. Adjustments are made for non-integral millisecond segment lengths.

Abstract: Providing a noise signal comprises providing a first signal corresponding to a first band of a frequency spectrum of the noise signal and providing a first signal low corresponding to the first band of the freguency spectrum of the noise signal. Next, providing a noise signal comprises providing a second signal corresponding to a second band of the frequency spectrum of the noise signal, the second signal based on the first signal low. And finally, the first signal and the second signal are summed to provide the noise signal.

Abstract: A novel method and apparatus for improving transmit antenna weight tracking using channel vector element to element correlations in a wireless communication system is disclosed. The present channel autocorrelation tracking technique utilizes the observation that tracking can be improved when a channel gain vector contains correlated elements. In a first embodiment of the autocorrelation tracking technique, the present invention extracts a coarse gradient estimate by utilizing a perturbation vector autocorrelation matrix estimate and a perturbation autocorrelation matrix to update TxAA weight vectors accordingly. In a second embodiment of the channel autocorrelation tracking technique, the present invention extracts a coarse gradient estimate by utilizing eigendecompositions, perturbation vector autocorrelation matrix estimates, and perturbation autocorrelation matrices to update TxAA weight vectors accordingly.

Abstract: Multi-phase clocks are used to encode and decode signals that are phase-modulated. The input signal is phase-compared with a feedback clock. Phase differences increment or decrement an up/down counter. The count value from the up/down counter is applied to a phase rotator, which selects one clock phase from a bank of multi-phase clocks. The multi-phase clocks have the same frequency, but are offset in phase from each other. An output divider divides the selected multi-phase clock to generate a phase-modulated output. A feedback divider divides a fixed-phase clock from the multi-phase clocks to generate the feedback clock. An analog or a digital front-end may be used to convert analog inputs to digital signals to increment or decrement the counter, or to encode multiple digital bits as phase assignments. For a de-modulator, a digital-to-analog converter (DAC) or a digital decoder produces the final output from the count of the up/down counter.

Abstract: A Spread Spectrum system acquires signals with frequency uncertainty. The present invention independently computes the number of frequency bands necessary to cover the carrier frequency uncertainty and the chip rate uncertainty and uses the largest of the two quantities in the acquisition process. A receiver cycles through pseudonoise code phases until a matched filter output exceeds a threshold. The local code is adjusted based on that code phase and the signal is processed for carrier acquisition, where an FFT estimates the carrier frequency. The code phase and nearest neighbors are used to determine the presence of a false alarm. When a false alarm is absent, the detection is examined for an alias or noise spur. If an alias is absent, the signal search is complete. Otherwise, processing continues to search for a pseudonoise code. The process continues by examining all code phases for each band until a signal is detected.

Abstract: A method for compensating a baseline wander of a transmission signal and related circuit are provided. The transmission signal includes a plurality of first pulses and a plurality of second pulses for representing digital data coded in the transmission signal. The method includes generating an accumulation result according to a number of the first pulses and a number of the second pulses for estimating the baseline wander of the transmission signal, and compensating the baseline wander of the transmission line according to the accumulation result.