Abstract: A pilot structure, a method, and a receiver for multi-carrier cellular communications defining a specific Time Division Multiplexer/Multiplexing pilot pattern and pilot sequence for a sub-frame with short system information. A primary synchronization sequence is configured to be transmitted every predetermine number of sub-frames in a defined bandwidth. A primary common pilot is configured to be transmitted for each sub-frame. Short system information is configured to be transmitted once per frame to define the pilot structure of sub-frames in a frame period to define a structure of a frame period.

Abstract: A circuit is designed with a matched filter circuit including a plurality of fingers (700, 702, 704) coupled to receive a data symbol. Each finger corresponds to a respective path of the data symbol. Each finger produces a respective output signal. A plurality of decoder circuits (706, 708, 710) receives the respective output signal from a respective finger of the plurality of fingers. Each decoder circuit produces a respective output signal. A joint detector circuit (1310) is coupled to receive each respective output signal from the plurality of decoder circuits. The joint detector circuit produces an output signal corresponding to a predetermined code.

Abstract: In a method of forming a beam, data signals and pilot signals are generated by despreading signals that are received by a plurality of antennas, the received signals including a modulated data signal and a modulated pilot signal, respectively. A first covariance matrix is calculated for the pilot signals. A second covariance matrix is calculated for averages of the pilot signals. A weight vector is calculated based on the first and second covariance matrices. A beam forming output signal for forming a beam is generated based on the data signals and the weight vectors. Therefore, an optimal beam may be accurately formed.

Abstract: A closed-loop signalling method controls multiple transmit beams. The method also includes transmitting a plurality of beams from a first transceiver via a plurality of transmission channels to a second transceiver, evaluating, at the second transceiver, characteristics of the plurality of transmitted beams received at the second transceiver. The method also includes deriving, at the second transceiver, beamforming information for being fed back from the second transceiver to the first transceiver based on the evaluated characteristics. The beamforming information is usable for controlling, at the first transceiver, the transmitting of the plurality of beams. The method also includes selecting, at the second transceiver, at least one set of beamforming information for being fed back from the second transceiver via a feedback path to the first transceiver.

Abstract: Demodulator architectures for processing a received signal in a wireless communications system. The demodulator includes a number of correlators coupled to a combiner. Each correlator typically receives and despreads input samples (which are generated from the received signal) with a respective despreading sequence to provide despread samples. Each correlator then decovers the despread samples to provide decovered “half-symbols” and further demodulates the decovered half-symbols with pilot estimates to generate correlated symbols. The decovering is performed with a Walsh symbol having a length (T) that is half the length (2T) of a Walsh symbol used to cover the data symbols in the transmitted signal. The combiner selectively combines correlated symbols from the assigned correlators to provide demodulated symbols. One or more correlators can be assigned to process one or more instances of each transmitted signal.

Abstract: The disclosed embodiments may relate to a method and apparatus for performing a correlation with respect to a received signal. A first correlator may correlate for a real part of a first characteristic of the received signal to produce a first real correlated signal. A second correlator may correlate for an imaginary part of the first characteristic of the received signal to produce a first imaginary correlated signal. A third correlator may correlate for a real part of a second characteristic of the received signal to produce a second real correlated signal. A fourth correlator may correlate for an imaginary part of the second characteristic of the received signal to produce a second imaginary correlated signal.

Abstract: Implementation of an improved matched filter system for despreading a PN code from a spread spectrum signal utilizes a matched filter system that may be broadly conceptualized as a system that optimizes the number of multipliers and adders utilized by the system in despreading a PN code from a spread spectrum signal. This lowers the power consumption of the improved matched filter system and increases the speed at which the system despreads the PN code from the spread spectrum signal.

Abstract: A system and method for detecting a presence and frequency offset of a spread spectrum radio frequency signal is disclosed. The method comprises receiving the spread spectrum radio signal. The signal can be sampled to form a plurality of signal samples. Each signal sample can be multiplied by a complex conjugate of a proximate signal sample to form a plurality of signal sample pairs. The signal sample pairs can be summed over a predetermined dwell time period to form a data vector having a magnitude and angle offset to enable detection of the signal and to enable a frequency offset between the spread spectrum radio frequency signal and a receiver frequency reference to be determined.

Abstract: A data processing apparatus able to start decoding at a timing earlier than the conventional timing and able to reduce the storage capacity required for a storing means for storing the encoded data until a decoding side decodes the input encoded data in comparison with the conventional storage capacity, which apparatus selects frame data from frame data f(5) having the last decoding order to frame data f(0) having the first decoding order for processing for calculating a delay time min_delay and calculates the delay time min_delay. It calculates the delay time min_delay indicating the delay time from when the decoding side starts to receive input of the frame data to when the data is decoded based on the specified size and the bit rate of the input of the frame data to the decoding side for each of the frame data for processing.

Abstract: Provided is a correlation apparatus based on symmetry of a correlation coefficient that can reduce complexity of hardware by reducing the number of adders and multipliers. Accordingly, when values of a real number part and an imaginary number part are exchanged with respect to a middle point of a correlation coefficient sequence and divided into two parts of left and right by the middle point of the correlation coefficient sequence, the values of the real number part and the imaginary number part are even-symmetrical with respect to the middle point of the divided two parts. Therefore, the number of the adders required for forming the correlation apparatus is reduced by at least 20% and the number of the multipliers is reduced by at least 70% in comparison with the 62 adders and the 64 multipliers required for a conventional correlation apparatus.

Abstract: Embodiments of an adaptive in-phase (I) and/or quadrature-phase (Q) imbalance correction for multicarrier wireless communication systems is generally described.

Abstract: A rake receiver for DS-CDMA UWB system and a DS-CDMA receiver having the same are provided. The rake receiver includes: a channel estimator for estimating a channel having a predetermined chip duration by using a synchronization acquisition sequence; a tracking module for detecting a channel variation and adjusting a synchronization position value when the channel variation is detected; a first switch for selecting one of an output value of an analog-to-digital converter and an output value of a correlator and outputting the selected value; a second switch for selecting one of the output value of the analog-to-digital converter and the output value of the correlator; and a plurality of demodulators having a parallel processing structure to demodulate received signals by using the channel estimation value inputted from the channel estimator, the synchronization position value stored by the tracking module, and an output value of the second switch.

Abstract: A method of ameliorating channel effects present in a signal received through a channel, wherein the signal conveys at least first and second information streams and the method comprises the steps of determining from the first stream activation of the second stream and processing the signal to ameliorate channel effects, when the second stream is present, in a first manner comprising filtering the signal through filter means to ameliorate channel dispersion and then processing the signal through Rake receiver means or, when the second stream is absent, in a second manner comprising processing the signal through the Rake receiver means without prior amelioration of channel dispersion by the filter means.

Abstract: Wireless communication receiver with hybrid equalizer and RAKE receiver. The receiver compares performance of the system for RAKE only and RAKE in combination with equalizer estimates. The receiver enables or disables the equalizer accordingly.

Abstract: The present invention discloses a method for detecting orthogonal code CDMA signal implemented mainly through the following steps: estimating the total power of interference to the multi-path signals; performing matched filtering on the multi-path signals and performing maximum ratio combining on the multi-path signals by utilizing the total power of interference to the multi-path signals, to obtain the optimized matched filtering result; and performing joint detection on the optimized matched filtering result. There are two schemes for implementing: if the optimized matched filtering detection scheme is used, only the first two main steps are executed; if the joint detection scheme is used, all of the three steps are executed. In either of above two schemes, the interference code channels involved in the estimation of total power of interference to the multi-path signals are need to be selected, i.e.

Abstract: A system and method for detecting a spread spectrum encoded message within a received signal is described. The spread spectrum encoded message has an unknown code phase, unknown code frequency offset, and unknown carrier frequency offset. A plurality of code phase hypotheses, code frequency offset hypotheses, and carrier frequency offset hypotheses are searched in parallel. The unknown code phase, unknown code frequency offset, and unknown carrier frequency offset may also be estimated.

Abstract: A Node-B/base station has an access burst detector. The access burst detector comprises at least one antenna for receiving signals from users and a pool of reconfigurable correlators. Each correlator correlates an inputted access burst code at an inputted code phase with an inputted antenna output. An antenna controller selectively couples any output of the at least one antenna to an input of any of the correlators. A code controller provides to an input of each correlator an access burst code. The code controller controls the inputted code phase of each controller. A sorter/post processor sorts output energy levels of the correlators.

Abstract: An apparatus and a method for tracking a sampling clock of a multi-carrier communication system are disclosed, the apparatus including a data removal module, a phase estimation module, and a sampling clock offset computation module. The data removal module is for generating a plurality of first and second data removal symbols by removing predetermined transmitted data from a plurality of first and second received symbols, respectively. The phase estimation module for generating a first and a second phase shifts according to correlations of the plurality of first and second data removal symbols. The sampling clock offset computation module for generating a control signal utilized to compensate the sampling clock of a plurality of received symbols according to the first and a second phase shifts.

Abstract: A method for estimating the speed of a mobile device in a network is provided that includes selecting a correlation length from a plurality of possible correlation lengths. A correlation result is generated based on the selected correlation length. A speed estimate is generated for the mobile device based on the correlation result.

Abstract: Apparatus, and an associated method, for designing codes to be used to code data that is communicated in a multi-access communication system. A selected code is designed, based upon an initial code. The selected code that is designed is of characteristics that best optimize channel differentiation to minimize interference between concurrently-communicated data coded by different codewords of the selected code.

Abstract: A multiuser detector system with correlation based pruning including a parameter estimation module adapted to receive complex signals, and to produce estimated signature waveforms for each of K co-channel interfering signals. Pre-processing the estimated signature waveforms using an S-matrix module and producing a more valid set of hypotheses, wherein the S-matrix module uses apriori knowledge of an unnormalized cross correlation matrix, and processing the more valid set of hypotheses for pruning with an M-algorithm in a multiuser detector module. An improvement to the M-algorithm in which the interference structure based on the signal correlation matrix used during the optimization process aids in selecting a better subset of hypotheses to test. This approach has the benefit of reducing computational complexity and improving performance over the existing M-algorithm.

Abstract: A parallel correlator and method includes temporarily storing in a series of P sequence registers, each of length R1, serial bit-sequences of a code of length N=P*R1. In a first-level of processing, certain unique bit sequences are inverted to reduce the number of unique bit sequences by half. Identical bit-sequences are then combined and temporarily stored in a first-level sub-accumulation register. Alternatively, bit sequences differing by only one bit may be combined in a common first-level sub-accumulation register. Further levels of similar processing may be imposed, where each subsequent level taps and inverts only a portion of the bits in the above level of processing, thereby reducing the number of unique bit sequences. Finally, all negative energy is combined in one register position, inverted, and added to all positive energy in the other register positions.

Abstract: The present invention relates to a filter apparatus and method having a fixed aspect for providing a predetermined selectivity and having an adaptive aspect for determining the frequency response of said filter apparatus. The adaptive aspect is controlled to change the frequency response. Predetermined zero values of the filter characteristic are set to provide a predetermined filter selectivity; and at least one filter parameter is controlled to change pole values of the filter characteristic so as to provide frequency response adaptation. Thereby, the frequency response of the filter operation can change while the filter selectivity can be maintained. The filter apparatus is thus able to cope with advanced system requirements while keeping the complexity and power consumption low.

Abstract: A system and method for determining a fine frequency offset of a composite code spread spectrum signal is disclosed. The method includes despreading at least one component of the composite spread spectrum signal to form a partially despread composite spread spectrum signal. A set of on-time samples are selected from the signal. The set of on-time samples are rotated by a predetermined frequency amount. The set of rotated samples are placed into a plurality of frequency bins, with each frequency bin representative of a different frequency estimate. An energy for the signal in each frequency bin is determined to find the bin having the greatest energy.

Abstract: A correlator despreads a P/N long code constructed from two or more constituent codes A, B, C having N, M and L elements respectively. In a third stage, L filter taps decorrelate elements of the third constituent code from the input received signal, leaving elements of code AB. The outputs of the third stage delay line are summed and input into a second stage delay line having M filter taps to decorrelate the elements of the second constituent code from the input to the second stage, leaving elements of code A. The outputs of the second stage delay line are summed and input to a first stage delay line having N filter taps. The output of the first stage delay line is summed and input into a shift register. An energy peak in the shift register indicates the phase of the P/N elements in the register is proper.

Abstract: A code division multiple access (CDMA) radio system uses an adaptive filter in a receiver to mitigate multipath radio propagation and to filter out interfering signals. Characteristics of an initial stage of the filter preferably are determined by cross correlation of a generated pilot signal and the input signal with the integration of the correlation performed over a time period selected to be an integral number of symbol periods. The integration causes the portions of the cross correlation corresponding to the user subchannels to average substantially to zero, so that the pilot channel signal correlation is the primary contribution to the signal used to characterize the channel to establish the coefficients of the adaptive filter for the receiver.

Abstract: A multimode communication device with a shared signal path programmable filter and a method for utilizing a shared signal path programmable filter in a multimode communication device. Various aspects of the present invention comprise a first module adapted to receive a first communication signal (e.g., corresponding to a first communication protocol) and a second module adapted to receive a second communication signal (e.g., corresponding to a second communication protocol). A shared filter, communicatively coupled to the first and second modules, may be adapted to filter the first and/or second communication signals in accordance with a plurality of selectable sets of filter response characteristics (e.g., associated with the first and second communication protocols). A filter control module may be adapted to select a set of filter response characteristics from a plurality of such sets and program the shared filter to filter a communication signal in accordance with the selected set.

Abstract: The frame of data is partitioned into a plurality of portions of data symbols. A plurality of channel elements is assigned to demodulate data symbols of correspondingly the plurality of portions of data symbols. The number of the plurality of portions of data symbols is higher in a case at high data rate than a case at low data rate.

Abstract: An apparatus and method for tracking a sampling clock are disclosed. The apparatus includes a compensating circuit compensating phases of a first and a second received symbols according to a compensating signal and thereby generating a first and a second compensated symbols; a data removal circuit removing a first predetermined transmitted data from the first compensated symbol, and a second predetermined transmitted data from the second compensated symbol and thereby generating a first and a second data removal symbols; and a computing circuit generating a sampling clock offset according to the first and the second data removal symbols, and adjusting the sampling clock signal according to the sampling clock offset.

Abstract: A Kerdock decoder of the present invention generates correlation reliability from a relation between correlation values to output together with a Kerdock-decoded map data. A map deciding unit receives a field sync signal, a field identifying signal, the Kerdock-decoded map data and the correlation reliability to identify whether a current field is an odd or even field and whether there is a map change in case of the even field. And, the map deciding unit decides a current map data by performing map acquisition and tracking according to the corresponding result.

Abstract: A packet detector for a multi-band orthogonal frequency division multiplexing system includes a plurality of packet detection units each corresponding to a time frequency code for detecting packets according to a spreading sequence of the time frequency code, a comparison unit for comparing correlation values provided by division units of the plurality of packet detection units, and a packet decision module for determining a time frequency code and size of a fast Fourier transform sampling window according to output signals of the comparison unit, allowing a frequency band to be selected and synchronization to be executed.

Abstract: The invention discloses a method of applying a long cell-code in a joint detection system. At transmitters, multiples of the spreading code (spreading factor) is taken as the length of the long cell-code to scramble the signal, and at receivers, the method still takes the multiuser detection to process the received signal.

Abstract: Combinations of correlation results are used to achieve detection of multiple coded signals at a receiver in a wireless communications system. The code applied to signals includes a lower rate code and a higher rate code. The lower rate code is a nested or tiered code such that it comprises at least two code sequences of the higher rate code. The received coded signal is correlated with the higher rate code using a single higher rate correlator to provide a higher rate code correlation result. The higher rate code correlation results are fed to two or more lower rate code correlators that combine multiple higher rate code correlation results, each using a different lower rate code, to provide corresponding lower rate code correlation results. The presence of at least one coded signal or mutually exclusive coded signals can be determined from the lower rate code correlation results.

Abstract: A novel UWB communications method and system that provides self-organization for wireless sensor networks is introduced. The self-organization is in terms of scalability, power conservation, channel estimation, and node synchronization in wireless sensor networks. The UWB receiver in the present invention adds two new tasks to conventional TR receivers. The two additional units are SNR enhancing unit and timing acquisition and tracking unit.

Abstract: A method and apparatus for a spread spectrum matched filter with Doppler correction suitable for using in a radio frequency receiver. The system includes a signal sampler operable to receive signal data and a Doppler shift system operable to provide a Doppler shift correction value. The system also includes a time domain signal processor in signal communication with the signal sampler, the Doppler shift system and the code signal input, the time domain signal processor operable to shift the signal data by the Doppler shift correction value and to determine a correlation between the shifted signal data and the code signal input. The system reduces a waveform representing Doppler correction values into a Boolean combination that may selectively represent the waveform and be implemented by the processing of a matched filter.

Abstract: Exemplary received signal processing may be based on maintaining a model of received signal impairment correlations, wherein each term of the model is updated periodically or as needed based on measuring impairments for a received signal of interest. An exemplary model comprises an interference impairment term scaled by a first model fitting parameter, and a noise impairment term scaled by a second model fitting parameters. The model terms may be maintained based on current channel estimates and delay information and may be fitted to measured impairment by adapting the model fitting parameters based on the measured impairment. The modeled received signal impairment correlations may be used to compute RAKE combining weights for received signal processing, or to compute Signal-to-Interference (SIR) estimates. Combined or separate models may be used for multiple received signals. As such, the exemplary modeling is extended to soft handoff, multiple antennas, and other diversity situations.

Abstract: Method and apparatus for packet detection is described. More particularly, a signal having sub-signals is received. The signal is quantized (“re-quantized”) to provide a quantized signal to processing units, where the quantized signal is a sequence of samples. A cross-correlation is done between the sequence of samples and a reference template, including totaling partial results from the processing units to provide a result. The result is a symbol timing synchronization responsive to the cross-correlation, which is provided in part by combining by addition or subtraction a regression vector obtained from the sequence of samples and a coefficient term vector obtained from the reference template.

Abstract: A scrambling code generating apparatus of a downlink transmitter in a UMTS mobile communication system, which uses one primary scrambling code for separation of base stations and multiple secondary scrambling codes for channel separation. The apparatus includes a first m-sequence generator for generating a first m-sequence and a second m-sequence generator for generating a second m-sequence. A first summer adds the first and second m-sequences to generate the primary scrambling code. A plurality of first masking sections each shift the first m-sequence, and a plurality of second masking sections corresponding to the respective first masking sections each shifts the second m-sequence. A plurality of second summers each adds one of the first shifted m-sequences with the second m-sequence corresponding to the first m-sequence. The output of the second summers thus generates the multiple secondary scrambling codes.

Abstract: The invention generally relates to improved correlators for spread spectrum receivers, particularly for third generation mobile communications systems. A Golay correlator with a plurality of delay structures is described. At least one of these delay structures includes a plurality of memory elements sharing a common input bus; and a circular shift register having a plurality of bit positions, one for each of the memory elements, each bit position storing a single bit and having an associated bit position output, each bit position output being coupled to corresponding memory elements for enabling writing of data into the memory element when the bit position output is active; and wherein, in use, only one of the bit positions in the circular shift register is active, the active bit position moving circularly through the shift register to select the memory element into which data on the common bus is written.

Abstract: A autocorrelation peak detector (54) and a interference-reducing timing generator (55) decide interference-reducing timings ?±(?2??1) for eliminating interference components that arrive from an adjacent base station, and a path searcher (53) decides the path timing ? of multipath from a base station with which communication is currently in progress. A despreading timing decision unit (56) decides a plurality of despreading timings ?, ?±(?2??1) from the above-mentioned timings, fingers (571 to 573) despread a receive spread-spectrum signal at respective ones of the despreading timings, and a RAKE combiner (58) weights and combines a plurality of results of despreading to thereby diminish interference components.

Abstract: A composite code is made for example by exclusive-OR'ing each real element of a first constituent code A with each element of a second constituent code B to obtain a basic composite code. To suppress autocorrelation, differing numbers of doping code elements are inserted between code segments made from combining each element of code A with an element of code B. A matched filter first stage removes from its input the A code and any doping code added to it, summing the elements of code A. A matched filter second stage removes from its input the B code and any doping code added at the second level. The summed elements of code B are the input to the first stage. Optionally, the summed elements of the doping code at any level may be delayed and summed with the elements of the A code in the first stage.

Abstract: A digital broadcasting receiver, a driving method, and a self-diagnosis method thereof, are provided. The digital broadcasting receiver includes: a digital demodulator for demodulating a digital broadcasting signal; a lock detector for detecting lock signals from the digital demodulator; and a lock processor for controlling the digital demodulator according to the detected lock signal.

Abstract: A rake receiver for processing a multi-path input signal received from a communications channel, wherein each multi-path component of the multi-path input signal comprises one or more symbols, comprises a plurality of fingers and a demodulator. Each of the plurality of fingers is adapted to receive the multi-path input signal and provide a sequence of input samples corresponding to a multi-path component of the multi-path input signal. The demodulator is adapted (i) during a single clock period, to receive and process one or more input samples corresponding to only one of the fingers, (ii) for each of the fingers, to accumulate multiple processed input samples to form a symbol, and (iii) to provide the formed symbols for all fingers.

Abstract: A system and method for acquiring a transmitted spread-spectrum signal uses a matched filter configuration that is preferably employed as a Stage 2 filter in the second phase of an initial signal acquisition procedure performed in the receiver. In operation, a Stage 1 filter matches a sequence which is repeated a number of times according to a second sequence within a secondary synchronization sub-channel of the spread-spectrum signal. The Stage 2 filter of the invention then filters the output of the Stage 1 filter in order to recover a secondary synchronization code. The Stage 2 filters the output of the Stage 1 filter using three matched filters of its own. The first and second filters sample different taps of a sequence output from the Stage 1 filter. The third filter samples a predetermined number of taps overlapping taps for the first and second filters in a way that resolves ambiguities with respect to the identification of the sequence.

Abstract: A system and method for fast synchronization of an incoming signal with a UWB receiver. The present invention synchronizes a UWB receiver with an incoming signal. The present invention correlates a local pulse generated at the receiver with the incoming signal, finds the value in the correlation function that would correspond to a high signal to noise ratio, thereby matching the receiver to the incoming signal phase, and operates the receiver at that phase. Exemplary options of fast synchronization include a maximum peak detector.

Abstract: Provided are a pulse signal generator for UWB radio transception and a radio transceiver having the same. The pulse signal generator includes: an envelope generator generating a plurality of envelope signals; a local oscillator array composed of a plurality of high frequency oscillators, each outputting two oscillation signals having a phase difference from each other; a multiplier array receiving the envelope signals and the oscillation signals and outputting signals obtained by respectively multiplying the envelope signals by the oscillation signals; and an I channel adder and a Q channel adder outputting an I channel pulse signal and a Q channel pulse signal by adding output signals having the same phase components among the signals output from the multiplier array, respectively.

Abstract: A matched filter for implementing the correlation of an input signal and a reference signal. The matched filter comprises N parallel M-sample long shift registers for receiving an equal number of input signals at the sampling frequency of the input signal, wherein N?2, and then multiplexes one of the input signals and one of the reference signals at a time to calculation logic by applying alternately at least one combination of the input signals and the reference signals to the calculation logic. The calculation logic may then calculate the correlation time-dividedly for each combination of an input signal and a reference signal so that correlation results calculated from different signals appear at the output of the calculation means as a sequence.

Abstract: A method for synchronization of a mobile radio receiver having a time slot structure for a radio signal is disclosed. A data stream received by the mobile radio receiver is filtered in a filter, thereby producing a decision sequence of received data as a set of maximum possible determined time slot boundaries. The decision sequence is processed in a two-step method such that, in a first method step, a subset is selected from the decision sequence and, then, in a second method step, the elements of said subset are averaged over time, with the time slot boundary which is used for synchronization being obtained as the result of this averaging process. In this case, the subset is selected using statistical characteristics of those signal sample values that are associated with a time slot boundary, and of those signal sample values which are not associated with a time slot boundary.

Abstract: A method and an apparatus is disclosed for efficient cross correlation of a plurality of signal vectors. Incoming data is partitioned into several segments and processed according to an algorithm where data rotation is a function of post-correlation memory size.

Abstract: A receiver for transmission and parallel interference has multiple access interference suppression stages having K channels, each comprising a correlation device corresponding to a particular pseudorandom sequence and interference generation and suppression device. Each stage delivers to the following stage signals at least partly freed from multiple access interferences. A decision stage receives the signals from the channels of the preceding suppression stage. Each decision stage has a correlation device corresponding to one of the pseudorandom sequences and decision device to deliver data. Devices for producing synchronization signals can control the interference suppression and the decision device. The devices producing the synchronization signals have components placed in the channels of the final stage.