Abstract: A low-cost communication system utilizing a code division multiple access, which controls scale-up of an apparatus due to the provision of an interference suppressing function in a base transceiver station, prevents the reduction of channel utilization efficiency, and enables a high-quality communication. Conventionally, a signal obtained through an interference cancellation stage process has been processed at subsequent cascade-connected stages. The interference cancellation stage process has been carried out by cascade-connecting several circuits performing the same process in a multi-stage interference-canceling device. However, in the present invention, by performing a demodulation process for generating replica signals, feeding back the replica signals to a correlation circuit for another demodulation process, and repeating the same signal process, the interference cancellation stage process is carried out. Such a configuration enables reduction of hardware.

Abstract: A closed-loop transmitting antenna diversity method, and a base station and mobile station apparatus therefore in a next generation mobile telecommunications system, the closed-loop transmitting antenna diversity method having a plurality of antennas in a mobile telecommunications system, including the steps of (a) measuring the changed amount per unit time of the phase difference between antennas for each of the plurality of antennas which are used in a base station; (b) transmitting the result of measuring as feedback information for adjusting transmitting antenna diversity; (c) receiving and interpreting feedback information in the base station; (d) calculating the weighted value of array antennas for each antenna, using the interpreted feedback information; and (e) multiplying data which is to be transmitted from the base station to a mobile station by the array antenna weighted value, and outputting the result through a corresponding antenna.

Abstract: An apparatus and method are described in which a corrected signal-to-interference ratio (SIR) is determined in a cellular telephone receiver. First the estimated signal strength at the receiver is measured, then the estimated interference level is measured. The signal strength and the interference values are separately corrected in accordance with an algorithm. Thereafter, a corrected SIR value is obtained by dividing the corrected signal strength and the corrected interference values.

Abstract: A path detector (140) detects a plurality of multi-path waves that have satisfied a predetermined standard from reverse spread signals, a plurality of adders (161) form beams on the basis of a path, a plurality of transfer path estimating sections (170) and complex conjugate calculators (163) calculate a transfer path estimation value, and based upon the result of the estimation, carry out a weighting process in accordance with the signal amplitude and a removing process of the phase variations. Moreover, a plurality of interference amount estimating sections (171) extract the amount of interference, a plurality of normalizing sections (172) normalize the signals that have been subjected to the phase variation removing process based upon the amount of interference, an adder (185) combines all the signals that have been normalized, and a data determining section (190) determines the signal that have been combined.

Abstract: A receiver for the third-generation (“3G”) CDMA wireless system is disclosed. The receiver is adapted to mitigate the correlated interference by adaptive antenna process which will maximize the signal-to-interference-plus-noise ratio. After the mitigation of correlated interference from first step space process, the second step is to counter fading with MRC which is optimum after the mitigation of correlated interference. After these first two steps of interference mitigation by adaptive antennas and fading compensation through MRC, the decision signal for the first stage of MPIC will have the strongest desired part and least interference compared to any MPIC available. As can be appreciated, the first stage BER of the present receiver will be the lowest. Then, this low BER will result in a more accurate MAI regeneration, which will further cause a lower BER for the next stage and any subsequent stages.

Abstract: The present invention relates to an adaptive algorithm and device for the same, for calculating a weight vector to be applied to an adaptive array antenna system, suggesting an adaptive algorithm suitable for calculating an autocovariance matrix of signal vectors of signals received from antennas before despreading in a known channel code, and an autocovariance matrix of signal vectors of signals received from antennas after being despread in the known channel code. Particularly, the calculation is carried out with the autocovariance matrix of the signal vector before the despread divided into diagonal components and non-diagonal components.

Abstract: An object of the present invention is to estimate and compensate more accurately transmission channels in CDMA signal decoding. Memory means stores received despread data. Slot position detection means detects positions of pilot symbols. Pilot symbol averaging means obtains transmission channel estimation value per pilot block, by averaging a plurality of reception channels in each pilot block. The transmission channel estimation values are delayed by delay means, multiplied by their weight and added by multi-pilot block transmission channel estimation means. Here, the weighs are controlled adaptively by weight determination means in accordance with the state of the channel. Channel compensation means compensate m-th information symbol in the n-th slot including the pilot block on the basis of the estimation values obtained by the multi-pilot block transmission channel estimation means.

Abstract: A communication device including a per finger interference reducer adapted to remove an interference effect of at least one pilot signal from the output of a despreader of the finger.

Abstract: A single-user detection method operates to reduce the effects of interference in multi-user detection systems. Based upon a number of received user codes, a receiver defines a frame of symbols containing at least one window. A symbol amplitude of a single-user in a multi-user system is approximated over the window of the frame and a perturbative correction value is calculated based upon a correlation or decorrelation matrix, which is determined by the delay spread of the signals. An estimation of the symbol amplitude of the single-user signal is calculated over one or a number of windows of the frame. The single-user signal is detected when the symbol amplitudes of the entire signal within the frame has been calculated.

Abstract: A multipath mitigation method consists of locating a multipath-invariant (MPI) point of an ideal autocorrelation function and measuring the distance between the MPI point and DLL. The same MPI point is located in a received correlation function, and the distance between the point and the DLL, now affected by multipath, is measured. The difference between the ideal distance and the actual distance is the code tracking error resulting from multipath. The error is subtracted from the computed pseudorange or used to control the DLL. The method can be used to reduce the effects of all types of tracking error sources, such as signal transmission failure or code noise.

Abstract: An ultra-wide band (UWB) waveform receiver with noise cancellation for use in a UWB digital communication system. The UWB receiver uses a two-stage mixing approach to cancel noise and bias in the receiver. Self-jamming is prevented by inverting a portion of the received signal in the first mixer and then coherently detecting the partially and synchronously inverted signal in the second mixer. Since the drive signals on both mixers are not matched to the desired signal, leakage of either drive signal does not jam the desired signal preventing the receiver from detecting and decoding a weak signal.

Abstract: Power control bit generation for forward link power control in a spread spectrum communication system is accomplished through modification of a set point threshold. Modification of the set point reduces the number of squaring and division mathematical operations, thus more efficiently utilizing limited system resources in a mobile receiver used in forward link power control.

Abstract: The present invention relates to systems and methods that facilitate compensating for intersymbol interference (e.g. due to non-nyquist filtering) in Code Division Multiple Access (CDMA) systems (e.g., IS 95 and IS2000 systems). The subject invention employs equalization filters (e.g., T-spaced equalizers) at fingers of a RAKE receiver. By effecting such equalization filtering at a downstream point in a receiving system, e.g., at the fingers of the RAKE receiver, the filters can be run so as to operate at lower rates as compared to conventional systems where filtering is effected upstream where time is not necessarily known thus requiring equalization filters to operate at significantly faster rates (e.g., 2× or 4× expected chip rate). Accordingly, as compared to conventional systems where the matching filters often are of substantial complexity (e.g., >80 taps) the present invention provides for less complex equalization filters thereby reducing overall system complexity and cost.

Abstract: A method and apparatus for processing a received signal containing a desired burst and a co-channel interferer burst are disclosed. The invention includes receiving the received signal from a front end receiver. A time offset between the desired burst and the co-channel interferer burst is detected. A detection procedure is then selected based on the time offset between the desired burst and the co-channel interferer burst. Preferably, one of three detection procedures is selected based on the time offset detected and optionally the signal strength of the co-channel interferer burst. If a first or second time offset is detected, then a joint detection or an iterative detection procedure is selected and performed, respectively. Finally, if a third time offset is detected or if the co-channel interferer has a low signal strength, then a conventional detection procedure is selected and performed.

Abstract: A digital receiver detects symbols in a baseband signal in a DS-CDMA network. The receiver includes multiple spaced apart antennas. A time-frequency rake receiver is connected to each of the antennas. An interference canceller is connected to each output of each of the rake receiver. Each interference canceller produces a contributing symbol in parallel. A diversity combiner determines a decision symbol corresponding to the baseband signal from the contributing symbols.

Abstract: An apparatus and method for canceling pilot signals from neighbor base stations is disclosed. The present invention cancels unnecessary pilot signals transmitted from the neighbor base stations by detecting, analyzing a PN signal in a pilot signal of each base station, generating estimated interference signal according to analyzed information from the detected PN signal and subtracting estimated interference signal from the received signal. Therefore, the present invention increases a bandwidth of downlink transmission channel and improves the demodulator to be operatable in low signal-to-noise ratio (Eb/No).

Abstract: Techniques for polling fingers on a channel (which are fingers for which symbols are to be combined) to determine the last finger on the channel. As each finger is polled, the polled finger compares its state information with the state information for the channel to determine whether or not it is the last finger on the channel. The polled finger may be deemed as the last finger if (1) the polled finger is the current last finger, (2) the polled finger is later than the current last finger, or (3) all fingers on the channel have been polled and none of the fingers indicated that it is the last finger. If the polled finger is deemed as the last finger then, (1) the channel state information is updated with the polled finger state information, and (2) the symbols provided by the polled finger may be marked as being ready for subsequent processing.

Abstract: Iterative parallel interference cancellation estimations for signals received from multiple coded sources or a source with multiple coded outputs with updated estimates of interfering signals used during an iteration.

Abstract: In a mobile communication system, the tracking of synchronization is conducted in a stable state even in a multipath environment. A delay profile detector calculates a delay profile a(n) using a despread signal for each processing unit n. A delay profile averaging unit averages a(n) to produce Ave(|a(n)|2). A data symbol detector conducts rake combining of the despread signal using a(n) and Ave(|a(n)|2). According to a(n) and Ave(|a(n)|2, a weighting function unit calculates a representative value representing delay waves. A loop filter generates a control signal in response to the representative value. A clock controller controls a spread code generator according to the control signal.

Abstract: A method and system for canceling interference in a code division multiple access (CDMA) network. A transmitted signal is spread using a specific spreading sequence. The signal includes a plurality of symbols having a specific spreading factor that differs from the length of the spreading sequence. The transmitted signal is received and filtered using a plurality of despreading sequences to recover the transmitted signal, wherein each despreading sequence corresponds to a particular part of the spreading sequence and is used to despread a portion of the received signal that was spread using the corresponding part of the spreading sequence. Each despreading sequence is adapted to cancel interference caused by other signals, wherein such interference is associated with the part of the spreading sequence that corresponds to the despreading sequence.

Abstract: A multicast communication method in a CDMA mobile communication system which is capable of reducing a transmission power in a base station system, and is capable of performing an efficient multicast operation for a large number of mobile subscribers is provided. The starting of information distribution by a multicast operation and identification information indicating a content of the information thereof are notified through a broadcast channel to a mobile subscriber. Further, through the broadcast channel, information such as a spread code or the like to be used at this time, which is necessary for actual reception of communication data, is notified. Then, in the mobile subscriber, a surround environment of the mobile subscriber is checked to determine the possibility of simultaneous receiving from a plurality of other base station systems. If possible, similar notified information is also received from other base station systems.

Abstract: A Node-B/base station receiver comprises at least one antenna for receiving signals. Each finger of a pool of reconfigurable Rake fingers recovers a multipath component of a user and is assigned a code of the user, a code phase of the multipath component and an antenna of the at least one antenna. An antenna/Rake finger pool interface provides each finger of the Rake pool an output of the antenna assigned to that Rake finger. A combiner combines the recovered multipath components for a user to produce data of the user.

Abstract: Techniques to process a number of “received” symbol streams in a Multiple-Input Multiple-Output (MIMO) system with multipath channels such that improved performance may be achieved when using successive interference cancellation (SIC) processing. In an aspect, metrics indicative of the quality or “goodness” of a “detected” symbol stream are provided. These metrics consider the frequency selective response of the multipath channels used to transmit the symbol stream. For example, the metrics may relate to (1) an overall channel capacity for all transmission channels used for the symbol stream, or (2) an equivalent signal-to-interference noise ratio (SNR) of an Additive White Gaussian Noise (AWGN) channel modeling these transmission channels. In another aspect, techniques are provided to process the received symbol streams, using SIC processing, to recover a number of transmitted symbol streams.

Abstract: An apparatus and method for demodulating signals transmitted from one or more Node-Bs using transmit diversity methods determined on a Node-B basis in a mobile communication system based on code division multiple access (CDMA). In the apparatus, a plurality of fingers assigned on a path-by-path basis discriminates among multipath signals received from the one or more Node-Bs. A combiner selectively combines signals output from the fingers according to the use of transmit diversity. A transmit diversity signal processor demodulates the signals combined by the combiner on the basis of one transmit diversity method determined by a transmit diversity controller. The transmit diversity controller determines the transmit diversity method through transmit diversity information received from the Node-Bs, and controls the transmit diversity signal processor according to the determined transmit diversity method.

Abstract: A method reduces interference adaptively in a CDMA receiver. A baseband signal is demodulated to determine target symbols. The baseband signal is also demodulated to estimate interfering symbols. The interfering symbols are modulated to generate a cancellation signal, and the cancellation signal is subtracted from the base band signal to reduce interference in the target symbols.

Abstract: A code multiplexing transmitting apparatus spread-spectrum modulates transmission data of a plurality of channels by spreading codes that differ from one another, combines the spread-spectrum signals of each of the channels and transmits the resultant spread-spectrum modulated signal. A spread-spectrum modulating unit for each channel includes a phase shifter for shifting, by a predetermined angle channel by channel, the phase of a position vector of the spread-spectrum modulated signal of each channel. As the result of such phase control, the phases of pilot signal portions of the spread-spectrum modulated signals of the respective channels are shifted relative to one another so that the peak values of the code-multiplexed signal can be suppressed.

Abstract: The invention relates to a method for reducing the effect of multipath propagation in a receiver (1) in which a code-modulated spread spectrum signal is received. In the method, at least one reference code (r(x)) corresponding to a code used in modulation is used to form at least two reference signals with different phases. Correlation between a received signal and each reference signal is performed to form correlation values. The method also comprises the steps of forming a divider function and performing at least a deconvolution step, in which a first time-to-frequency transformation is performed on the corelation results to form first transform results, and the first transform results are divided by the values of the divider function to form a division result. The invention also relates to a receiver (1) for receiving a code modulated spread spectrum signal, and an electronic device (24) comprising at least a positioning receiver (1) with count (2) for receiving a code modulated spread spectrum signal.

Abstract: A novel and improved method and apparatus in a communication system (100) provides for efficient processing of received signals. The method and apparatus includes converting an encoded and spectrum spread received signal to received samples, determining a first channel estimate based on a first set of pilot signal samples. The first set of pilot signal samples are included in the received samples. The received samples are passed through a correlation and decoding process in accordance with the first channel estimate to produce decoded received samples. The decoded received samples are re-encoded and re-spreaded to produce re-encoded and re-spread samples. The re-encoded and re-spread samples are modified based on the first channel estimate to produce channel modified re-encoded and re-spread samples. The received samples pass through an interference cancellation that uses the channel modified re-encoded and re-spread samples to produce a new set of received samples.

Abstract: A Node-B/base station receiver comprises at least one antenna for receiving signals. Each finger of a pool of reconfigurable Rake fingers recovers a multipath component of a user and is assigned a code of the user, a code phase of the multipath component and an antenna of the at least one antenna. An antenna/Rake finger pool interface provides each finger of the Rake pool an output of the antenna assigned to that Rake finger. A combiner combines the recovered multipath components for a user to produce data of the user.

Abstract: A code division multiple access communication system transmits a pilot and traffic signal over a shared spectrum. The pilot and traffic signal have an associated code. Signals are received over the shared spectrum. The received signals are sampled. The samples are delayed to produce a window. The window has evenly time spaced samples. Each window sample is despread with a pilot code. A weight for each despread pilot code window sample is determined using an adaptive algorithm. Each window sample is despread with a traffic code. Each despread traffic code window sample is weighted with a corresponding weight of the determined weights. The despread traffic code window sample are combined as data of the traffic signal.

Abstract: Matched filters 102-1 to 102-n extract channel estimated values corresponding to users 1 to n by finding correlation with the reception signal. Threshold processing sections 103-1 to 103-n perform threshold processing on estimated power values obtained based on the channel estimated values corresponding to users 1 to n. JD section 104 performs matrix calculations using channel estimated values subjected to threshold processing. Multiplication section 105 performs a multiplication between the matrix calculation result and the reception signal. Identifier 106 performs hard decision on the multiplication result.

Abstract: In a mobile communication system, independent versions of a signal are transmitted over plural antennas. The antennas are either spatially separated or orthogonally polarized with respect to each other so that the independent versions of the signal are not subjected to correlated fading. Each independent version of the signal is transmitted from a respective antenna a fixed delay after transmission of a previous version of a signal from a different antenna. The fixed delay is at least one information bit of the signal. Received versions of the signal are equalized in an equalizer or RAKE architecture to provide a composite signal. The equalizer has respective sets of equalizer taps that are separated from adjacent sets of equalizer taps by the fixed delay. The RAKE architecture has respective sets of RAKE fingers that are separated from adjacent sets of RAKE fingers by the fixed delay.

Abstract: A transmitting side separates a transmission signal into a first information signal by a combination of spread codes and a second information signal except the first information signal, selects a combination of the spread codes corresponding to the first information signal, and performs spread modulation processing to the second information signal using the spread codes of the selected combination, and a receiving side performs despread processing to a received signal by the spread codes used on the transmitting side, selects a combination of the spread codes used on the transmitting side by use of a despread signal, and obtains the first information signal by the combination of the spread codes from the combination of the spread codes.

Abstract: A novel adaptive Bayesian multi-user receiver demodulating multi-user symbols in an HSDPA/TDD system in the presence of additive white Gaussian noise, unknown inter-cell interference (ICI), multi-access interference (MAI) and inter-symbol interference (ISI).

Abstract: A digital communication system comprises a transmitter for sequentially transmitting predetermined format data; and a plurality of receivers 102 each including a data selecting apparatus 104 for selecting required data from received data group and outputting selected data. The transmitter transmits data to the receivers in one of a first transmission mode having group destination directing information indicating that the data is to be transmitted to a receiving group consisting of predetermined receivers of the plurality of receivers, group specifying information for specifying a receiving group of receiving groups to which the data is to be transmitted, and in-group identification information for identifying a receiver in an arbitrary receiving group to which the data is to be transmitted, a second transmission mode having the group destination directing information and the group specifying information are included in the data, and a third transmission mode having the group destination directing information.

Abstract: A received signal averaging apparatus which includes an average operating section which averages input signals and outputs a filtered data, a data encoding section which encodes data lower than a threshold level and generates an encoded data, and an encoded data storing section which stores therein the encoded data outputted from the data encoding section, and the received signal averaging apparatus further includes a filtered data storing section for storing therein the filtered data and a data decoding section for decoding the encoded data stored in the encoded data storing section and outputs the data to the filtered data storing section.

Abstract: A system and method for transmitting a plurality of spread-spectrum signals over a communications channel having fading. The plurality of spread-spectrum signals are radiated by a plurality of antennas, with each antenna preferably spaced by one-quarter wavelength. A plurality of receiver antennas receive the plurality of spread-spectrum signals and a plurality of fading spread-spectrum signals. Each receiver antenna is coupled to a plurality of matched filters having a respective plurality of impulse responses matched to the chip-sequence signals of the plurality of spread-spectrum signals. A RAKE and space-diversity combiner combines, for each respective chip-sequence signal, a respective plurality of detected spread-spectrum signals and a respective multiplicity of detected-multipath-spread-spectrum signals, to generate a plurality of combined signals. The symbol amplitudes can be measured and erasure decoding employed to improve performance.

Abstract: A signal separator overcomes co-linear interference encountered in a wireless communication system base station by exploiting generally flat fading multipath characteristics of incoming signals. For this purpose, the invention employs diversity gained through the use of antenna array elements having different polarizations. An RF downconverter provides a signal separator with baseband, discrete-time digital samples of signal waveforms, received at one or more pairs of diverse polarization antenna elements. The signal separator weights and combines the baseband signals from the vertically and horizontally polarized received signals produced by the RF downconverter to estimate which signals emanate from which users. The signal separator uses polarization coefficients supplied by a coefficient calculator. To generate the polarization coefficients, the coefficient calculator is coupled to receive a set of channel fading coefficients from a channel estimator.

Abstract: A method and apparatus for preventing dropped calls in a wireless communication device. In one embodiment, the present invention is comprised of a method including the step of determining a characteristic of a first finger. Next, the present embodiment compares a characteristic of the first finger to a characteristic threshold. In this embodiment, provided the characteristic of the first finger does not meet the characteristic threshold, the present invention then determines if a second finger is present. Provided it is determined that a second finger is not present, the present invention prevents the first finger from being deassigned such that the first finger is not deassigned when only the first finger is present. In so doing, the present embodiment ensures that first finger is utilized (i.e. not dropped) even when the first finger does not meet a given characteristic threshold.

Abstract: An n-dimensional direct sequence spread spectrum modulator (10) comprises a spreading sequence generator (21) for generating a set of n/2 substantially mutually orthogonal spreading sequences. The spreading sequences each comprises combinations of the real and imaginary parts of complex sequences. A first frequency spreading arrangement (24,26) comprises a first input (24.1,26.1) for a first set of n/2 parallel input data streams (d1(t) d2(t)), a second input (24.2, 26.2) for the set of spreading sequences and an output (24.3, 26.3). Respective input data streams are associated with respective spreading sequences in the set of spreading sequences. A second frequency spreading arrangement (28,30) comprises a first input (28.1, 30.1) for a second set of n/2 parallel input data streams (d3(t), d4(t)), a second input (28.2, 30.2) for the set of spreading sequences and an output (28.3, 30.3). Respective input data streams being associated with respective spreading sequences in the set of spreading sequences.

Abstract: An adaptive weighted parallel interference cancellation system for CDMA that decreases MAI (multiple access interference) and thereby increases general performance, including K stages for iterative cancellation of MAI in a received signal of a user. Each stage includes a detector, a regenerator, and a subtractor. The detector is configured to determine a tentative bit decision from a despread signal. The regenerator that is connected with the detector in parallel is configured to spread an unmodulated signal, multiply a channel phase, and multiply by the output of the detector. The subtractor uses weighted signals that are adjusted user by user and according to changing environments.

Abstract: An improved multi-antenna receiver is realized for detecting signals transmitted by a multi-antenna transmitter by summing signals received at the plurality of receiver antennas after multiplying each by a respective constant. The summed signal is applied to a maximum likelihood detector. The respective constants, &lgr;j, where j is an index designating a particular receiver antenna, are determined by evaluating the largest eigenvector of the matrix A, where &Lgr; is a vector containing the values &lgr;j, and A is a matrix containing elements &agr;ij, which is the transfer function between the ith transmitter antenna to the jth receiver antenna. The &agr;ij terms are determined in the receiver in conventional ways.

Abstract: An automatic frequency control (AFC) loop circuit (1A, 1B) includes a mixer (2) for mixing a local oscillator signal (3) with a received signal to generate a result signal; a frequency detector (5) coupled to the result signal and outputting a loop error signal; a combiner circuit (9) for combining error signals output from a plurality of fingers (12, 14, 16) of a rake receiver (220) with the loop error signal output from the frequency detector to generate a combined loop error signal; a sign detector (10) having an input coupled to an output of said combiner circuit for outputting a sign detector output signal for indicating a sign of the combined loop error signal; control circuitry (7, 8) for controlling a frequency of the local oscillator signal in accordance with the sign detector output signal and a loop filter (6) partitioned into a first loop filter (6A) coupled between the output of the frequency detector and an input to the sign detector, and a second loop filter (6B) coupled between an output of th

Abstract: A method is provided for mitigating the multipath interference experienced by a present CCK symbol. This method first obtains a set of initial candidates for the present CCK symbol and a set of initial candidates for the next CCK symbol based on the ICI-corrected correlation outputs for the present and next CCK symbols, respectively. The method then obtains, for each of the candidates for the present CCK symbol, first ISI-mitigated correlation outputs where both the ICI due to the present CCK symbol and the ISI due to the next CCK symbol have been corrected. Thereafter, for each of the candidates for the present CCK symbol, and based on the first ISI-mitigated correlation outputs, the method obtains second ISI-mitigated correlation outputs where the ISI due to the previous CCK symbol has also been corrected. The present CCK symbol is then decoded based on the second ISI-mitigated correlation outputs.

Abstract: In a wireless communication system comprising an effective ray detector, a method for detecting and assigning a mobile station signal including receiving a plurality of search metrics, the plurality of search metrics including a plurality of offset energy values at corresponding time offsets, sorting the plurality of search metrics in order of their offset energy values, calculating a plurality of decoding success predictors, and selecting the decoding success predictor having the maximum value. The method also includes forwarding an acknowledgment message declaring signal detection to the mobile station if the maximum decoding success predictor has a value greater than zero. The method further includes assigning receiver demodulation at the time offsets associated with the maximum decoding success predictor if the maximum decoding success predictor has a value greater than zero.

Abstract: A direct sequence spread spectrum system in which a plurality of substantially redundant second blocks are derived from a first block of data. Each of the second blocks is spread using a distinct spreading sequence, and one or more signals representing each of the spread blocks is modulated and transmitted over a wireless interface. The transmitted one or more signals are received, and estimates of one or more of the second blocks derived therefrom. The first block is then estimated from one or more of the estimated second blocks.

Abstract: System and method for providing interference resistance in communications systems using closed-loop transmit diversity (CLTD). A preferred embodiment comprises: at a receiver, computing a CLTD weighting vector from a received signal, providing the CLTD weighting vector to a transmitter, and using the CLTD vector to suppress interference in the received signal, and at a transmitter, transmitting a signal, receiving the CLTD weighting vector from the receiver, and applying the CLTD weighting vector to all subsequent transmissions.

Abstract: A communication device includes at least one of path search means for detecting respective timings of path components included a signal received via a multipath propagation path using pilot symbols of a known phase included in said received signal and channel estimation means for estimating channel variation using the pilot symbols. The path search means includes a first path search part for detecting respective timings of path components using pilot symbols and a second path search part for detecting respective timings of path components using information symbols derived from a signal demodulated according to the timings detected in the first path search part and pilot symbols. The channel estimation means includes a pilot symbol acquiring part for acquiring pilot symbols included in the received signal and a channel estimation part for implementing channel estimation using the acquired pilot symbols.

Abstract: A receiver for a CDMA mobile radiocommunication system, receiving a signal which is a superposition of different signals, or path signals, corresponding to different propagation paths of a transmitted signal, which in turn is a superposition of different signals, or channel signals, corresponding to different channels carrying different transmitted informations, said receiver comprising, prior to the recovering of the transmitted information carried by a given channel, by exploiting said different propagation paths: means (6, 9) for estimating at least one received channel signal, or interferer signal, which is a superposition of different path signals corresponding to different propagation paths of a transmitted channel signal corresponding to at least one channel different of said given channel, means (10) for substracting said at least one estimated interferer signal, from said received signal.

Abstract: A radio apparatus includes a plurality of antennas, a plurality of spreading sections, a synthesizing section a converting section, a plurality of inverse spreading sections and a control unit. The plurality of antennas are provided at different physical positions to receive a radio wave signal, respectively. The plurality of spreading sections are provided for the plurality of antennas to spread the radio wave signal received by the plurality of antennas with spreading codes provided for the plurality of antennas to produce spread signals, respectively. The synthesizing section synthesizes the spread signals into an analog synthetic signal. The converting section converts the analog synthetic signal into a digital signal with a frequency such that a digital process can be applied to the digital signal.