Abstract: The present invention relates to an ultra-wideband signal receiver comprising: at least a first set of sampling cells for sampling the waveform of a received signal; at least a second set of sampling cells for sampling the waveform of the received signal, with a predefined delay ?; and at least one correlator for delivering information depending on the correlation between the waveforms thus sampled.

Abstract: An apparatus for processing spread spectrum signals is disclosed. The apparatus includes an intermediate frequency (IF) signal preprocessing unit, which includes a first set of multiply-accumulator (MAC) units and a second set of MAC units. The IF signal preprocessing unit generates a first and a second set of data streams using a digitized signal and a first and second local reference signals respectively. Each data stream is generated every predetermined time period, and each data stream includes pre-integration results generated at a predetermined rate.

Abstract: A low complexity RACH preamble detector is described herein. The RACH preamble detection algorithm uses the peak detection of the time domain correlation function through frequency domain processing. The frequency domain processing considers the reference signals generated directly from frequency domain CAZAC sequence or time domain CAZAC sequence with DFT conversion. A low-complexity poly-phase LPF along with down sampling is implemented before the FFT to reduce the required length of the long FFT operation N-folded.

Abstract: Systems (100) and methods (700) for processing a data signal in a communications system. The methods involve generating a first chaotic sequence at a transmitter (102). The methods also involve performing first basis function algorithms using the first chaotic sequence to generate first statistically orthogonal chaotic sequences. At least one sequence is selected from the first statistically orthogonal chaotic sequences for combining with a first data signal. The selected sequence is combined with a second data signal to obtain a modulated chaotic communication signal. The modulated chaotic communication signal is transmitted to a receiver (104). At the receiver, the received modulated chaotic communication signal is processed to obtain data therefrom. Notably, the signal processing generally involves performing a deterministic process (e.g., a Hidden Markov Model deterministic process).

Abstract: An adaptive transversal filter having tap weights Wj which are products of corresponding tap coefficients Cj and tap gains Mj is provided. A filter control loop controls all of the tap coefficients Cj such that an error signal derived from the filter output is minimized. One or more tap control loops controls a tap gain Mk such that the corresponding tap coefficient Ck satisfies a predetermined control condition. For example, |Ck| can be maximized subject to a constraint |Ck| Cmax, where Cmax is a predetermined maximum coefficient value. In this manner, the effect of quantization noise on the coefficients Cj can be reduced. Multiple tap control loops can be employed, one for each tap. Alternatively, a single tap control loop can be used to control multiple taps by time interleaving.

Abstract: An interference detector receives a data stream including predetermined symbols that include a first data and a second data, between which is a frequency offset. The interference detector includes a correlation apparatus that generates a first correlation result and a second correlation result according to the data stream; a power searching unit, coupled to the correlation apparatus, that generates a first maximum correlation result and a first neighboring power according to the first correlation result, and generates a second maximum correlation result and a second neighboring power according to the second correlation result; and a determining unit, coupled to the power searching unit, that generates a determination result according to the first maximum correlation result, the first neighboring power, the second maximum correlation result and the second neighboring power to indicate existence of interferences.

Abstract: A method of evaluating the usage in a received signal of codes from a tree of codes that can be used to orthogonalise communications signals, the method including testing to determine if a given code is in use in the received signal and deducing from the result and from the tree structure the need to test in the received signal for the use of the codes in the portion of the tree depending from said given code. The invention also includes corresponding apparatus and software.

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: The present invention includes a method of determining a phase estimate for an input signal having pilot symbols. The method includes receiving a plurality of pilot symbols, and then multiplying two or more pilot symbol slots by corresponding correlator coefficients to correct a phase estimate of the input signal.

Abstract: Described herein are code-modulated multi-signal systems. In one embodiment, a multi-signal system receives multiple input signals and code-modulates each input signal with a unique code to distinguish the input signal from the other input signals. The input signals may come from multiple antennas, multiple sensors, multiple channels, etc. The code-modulated signals are then combined into a combined signal that is sent through shared blocks and/or transmitted across a shared medium in a shared path. After shared processing and/or shared transmission, the individual signals are recovered using matched filters. Each matched filter contains a code corresponding to one of the unique codes for recovering the corresponding signal from the combined signal. The recovered signals may then be inputted to additional processors for further processing.

Abstract: A receiving device for spread spectrum communication includes a phase determining unit and a data demodulating unit. The receiving device receives a signal spread and modulated with first spreading code. The phase determining unit calculates a cross correlation between the received signal and a second spreading code and determines a phase P(0) of the received signal based on the cross correlation. The data demodulating unit synchronizes the phase P(0) and the first spreading code and despreads and demodulates the received signal with the first spreading code. The number of components in each of the first spreading code and the second spreading code is an integer greater than or equal to 2.

Abstract: A CDMA receiving apparatus includes a path searcher which outputs path timing that corresponds to sample timing where a correlation value between a received data sequence and a reference code sequence reaches a peak, and outputs the correlation value calculated at a sample timing adjacent to the path timing as an adjacent timing correlation value; an interpolation adjuster; and a despreader which despreads an output of the interpolation adjuster at the path timing, wherein the interpolation adjuster includes an interpolator for generating an interpolating data sequence which is a data sequence displaced in time by a specified fraction of one sample period with respect to the received data sequence, and outputs the received data sequence or the interpolating data sequence by switching therebetween based on a result of a comparison between the correlation value calculated at the path timing and the adjacent timing correlation value.

Abstract: A two-dimensional filter arithmetic device comprises a picture memory, a line memory, a vertical filtering unit which includes nine first filter modules installed in parallel, a buffer for timing adjustments, and a horizontal filtering unit which includes four second filter modules installed in parallel. From the line memory, the pixel values of nine full pels per line are inputted in parallel to the vertical filtering unit, nine vertically-filtered values of half pels are generated and inputted to the horizontal filtering unit; thereby, four two-dimensionally-filtered values of half pels are generated.

Abstract: The present invention relates a system and method for mitigating impairment in a communication system. In one embodiment, the system comprises a transmitter adapted to transmit at least one signal and a receiver adapted to receive the at least one signal and mitigate inter code interference in the signal using at least one inter code interference coefficient.

Abstract: In a wireless communications system which hops from frequency to frequency, rather than hopping according to a fixed dwell interval and a pre-determined pseudo-random hop sequence, a quality-based frequency hopping methodology is defined in which a new frequency is hopped to when the channel quality on the current frequency degrades based on the measured value or values of one or more predetermined metrics that are associated with channel quality. When triggered to hop to a next frequency, the hop-to-frequency may be the next frequency in the pseudo-random hop sequence known to both the transmitter and receiver or, in order to improve the reliability of communications, may be determined based on channel quality measurements on different potential hop-to-frequencies.

Abstract: The invention relates to the acquisition of a code modulated signal, wherein a first set of correlation results for correlations between the code modulated signal and a first replica code with different code phases and a second set of correlation results for correlations between the code modulated signal and a second replica code with different code phases are available. In order to achieve a high sensitivity, results from both sets of correlation results are combined, wherein correlation results used in the combination are selected based on information on a relative difference between a correct code phase for both replica codes. Then, it is determined based on the combination whether at least one of the sets of correlation results comprises a correlation result representing the correct code phase for the first replica code or the second replica code, respectively.

Abstract: An apparatus and method for processing a signal using a single correlator are provided. The apparatus may include a first storage unit storing satellite signal samples, a correlator receiving the satellite signal samples stored in the first storage unit in units of at least two satellite signal samples and performing correlation, and a controller storing the satellite signal samples received from an RF terminal in the first storage unit and controlling the correlator based on a predetermined control value. Accordingly, it is possible to ensure speed and performance even when tracking a plurality of satellite signals using a single correlator.

Abstract: Methods and apparatus are provided for use in devices operatively enabled to perform waveform correlation result processing.

Abstract: A signal processing unit and a wireless communication device are provided for making it possible to detect a frequency by means of a small scale operation circuit in a short time.

Abstract: Direct detection of wireless interferers in a communication device for multiple modulation types. One or more radios implemented within a communication device is/are operative to receive and process wireless communications. A wireless communication signal is processed to extract symbols there from. Various symbols groups are processed in accordance with correlation processing to identify potential interferers (e.g., other communication devices using common portions of frequency spectra). Alternatively, matched filter processing (e.g., using a Barker matched filter in some embodiments) operates on the various symbol groups to identify some potential interferers. Various combinations of correlation processing and matched filter processing may be employed in other instances (e.g., using any of a desired means of comparison, combining, etc.) in considering interferers identified in accordance with each of these two means.

Abstract: In one embodiment, a method for demodulating and searching for a preamble signal containing a complex phasor signal is disclosed. The complex phasor is demodulated using a phasor-rotated fast transformer. A received signal is correlated with a spreading code to produce a correlated signal. The correlated signal is coherently accumulated to produce a coherently accumulated signal. A first phasor-rotated signal transformation is performed on a real component of the coherently accumulated signal, and a second phasor-rotated signal transformation is performed on an imaginary component of the coherently accumulated signal. Finally, the signal power of the transformed real and imaginary components of the coherently accumulated signal is determined.

Abstract: A wireless transmission device enabled to improve an error rate performance at a receiver, by acquiring at least one of frequency diversity effect and a time diversity effect while keeping the interference resistance which is acquired by diffusion. In this transmission device, a modulation unit (101) modulates data to create a modulation symbol having in-phase components and quadrature components. An IQ individual spreading unit (102) arranges the diffusion chips, which are obtained by spreading the modulation symbol, of the in-phase components and the quadrature components, in areas extending in diffusion domains set individually for the in-phase components and the quadrature components. An IQ combining unit (103) combines the arranged spreading chips of the in-phase components and the quadrature components.

Abstract: Methods, systems, and apparatuses, and combinations and sub-combinations thereof, for down-converting an electromagnetic (EM) signal are described herein. Briefly stated, in embodiments the invention operates by receiving an EM signal and recursively operating on approximate half cycles (½, 1½, 2½, etc.) of the carrier signal. The recursive operations can be performed at a sub-harmonic rate of the carrier signal. The invention accumulates the results of the recursive operations and uses the accumulated results to form a down-converted signal. In an embodiment, the EM signal is down-converted to an intermediate frequency (IF) signal. In another embodiment, the EM signal is down-converted to a baseband information signal. In another embodiment, the EM signal is a frequency modulated (FM) signal, which is down-converted to a non-FM signal, such as a phase modulated (PM) signal or an amplitude modulated (AM) signal.

Abstract: Adaptation convergence in an adaptive dispersion compensation engine (ADCE) of a high-speed serial interface is detected by monitoring the output of the error amplifier of one or more adjustment loops of the ADCE. Adaptation convergence is considered to have been detected upon detection of a predetermined number of transitions in the error amplifier output, each of which occurs within a preselected interval following the previous transition. The detector may be implemented with a timer that times the preselected interval and a counter that counts transitions in the error amplifier output. The timer restarts each time a transition occurs, and the counter outputs a convergence signal when it reaches the predetermined number, but is reset each time the timer reaches the preselected interval. The serial interface may be part of a programmable integrated circuit device and in any case the preselected interval and the predetermined number may be programmable.

Abstract: The present invention relates to a method and a device for detecting active spreading codes for a signal in a communication system and estimating power of the active spreading codes. Further, the present invention ensures efficient interference cancellation. Multiple correlations are performed at a single level of a spreading code tree, the produced output samples are then observed at this level during a defined period, and a decision for the activity and power is met for all existing codes via extracting and processing information from these samples. At the correlation step, unitary fast Walsh Hadamard transformation is performed at practically the highest spreading factor in the system.

Abstract: The present invention is directed to a de-spreading method for a noncoherent receiver including: obtaining an output signal from a matched filter of a noncoherent receiver, which is PSK modulated and is at least two times upsampled; performing a noncoherent demodulation step including performing a differential operation on an in-phase and quadrature-phase components of the output signal of the matched filter to obtain a demodulated signal; and performing a de-spreading step on the demodulated signal with a PN table corresponding to the demodulated signal to obtain the de-spreaded data, wherein the PN table corresponding to the demodulated data contains chips which are either logic 1 or logic ?1. A noncoherent receiver is also provided.

Abstract: A matched filter and receiver is provided to delete the tap coefficients of a matched filter used in an OFDM receiver. In the matched filter and receiver, a transmitting signal is generated by using a symmetric series (Y) obtained from C[k]=exp[j*?*M/N*(k+0.5)^2], where X=[0, C[N/2], C[N/2+1], . . . , C[N?1], 0, 0, . . . , 0, C[0], C[1], . . . , C[N/2?1]], and Y=inverse FFT (X) as a base symbol. The matched filter, which detects the signal, reduces the number of multipliers by using the coefficient symmetric property.

Abstract: Provided is an apparatus for channel equalization in frequency domain, including: a channel estimation unit for estimating a channel on received signal from outside, a channel matched filter for changing channel characteristic of the channel estimated by the channel estimation unit and the received signal to channel characteristic to meet condition required for noncausal filtering, a noncausal filter for changing the channel characteristic changed by the channel matched filter from nonminimum phase channel to minimum phase channel, a reverse channel calculation unit for calculating a reverse of the channel changed by the noncausal filter in frequency domain, and a frequency domain equalization unit for performing channel equalization with respect to the channel changed by the noncausal filter in the frequency domain by using the reverse obtained by the reverse channel calculation unit as coefficients of the frequency domain equalization apparatus.

Abstract: Embodiments related to cross-talk mitigation are described and depicted.

Abstract: Provided is a matched filter whose circuit scale can be made significantly smaller by reducing the number of multipliers for a despreading process and the number of adders for an accumulating process. For each in-phase/orthogonal component, the matched filter includes a dual-port RAM that separates written samples into 128 groups each of 32 samples which are collectively read out group by group in order at a speed faster than a write speed in write mode, a bit separating section that separates data read group by group into 32 samples and simultaneously outputs the 32 samples, and 32 despreading/accumulating circuits that, with 16 samples sequentially input from 16 groups being taken as one block, sequentially despread individual samples, accumulate despreading results, and output accumulated values for each block.

Abstract: A method and apparatus are disclosed for modulating a communication signal in a code division multiple access (CDMA) environment using orthogonal N by N Hadamard spread spectrum codes Orthogonal spreading codes are used that have lengths that are not a power-of 2 to provide additional channel variability for various multimedia applications and increase the flexibility of the number of channels/bandwidth relationship. The Hadamard codes are multiples of 4 (4n) and demonstrate a good cross-correlation property, making them very useful in the flexible design of code division multiple access (CDMA) systems. A transmitter encodes each of N data streams (N not being a power of 2), to be transmitted using a 4n codeword, Ni. The received signal is passed through a filter matched to the characteristics of the appropriate codeword, Ni, and PN spreading sequence.

Abstract: A satellite signal receiver apparatus by which the hardware scale can be suppressed while high speed synchronization is assured. A carrier frequency component is removed from a satellite signal. Then, adding those of signals obtained after every period interval of spread spectrum codes and signals stored in a memory which have a same phase at the period intervals and writing an addition result back into the memory are repeated by a number of times corresponding to plural periods thereby to accumulate signals corresponding to sums of the signals added over the plural periods at the period intervals into the memory. Then, correlation calculation is performed between the signals for the one period of the spread spectrum codes corresponding to the plural periods and a spread spectrum code of the receiver side to detect a correlation point between the satellite signal and the receiver side spread spectrum code.

Abstract: The present invention relates to a method for detecting the presence or the absence of a spread spectrum signal in a frequency band of interest of a received signal, wherein: the autocorrelation function of said received signal is calculated for a set (S*) of non-zero time shift values (m); at least one cyclic correlation coefficient on (Rek?(m)) of the autocorrelation function is determined for said time shift values; the energy of the autocorrelation function is estimated from the quadratic sum of the values assumed by said cyclic correlation coefficient for said time shift values; the thereby estimated energy is compared with a predetermined threshold value and the presence or absence of said spread spectrum signal in the received signal is inferred from the result of the comparison.

Abstract: A wireless device (24) receives a reference signal over a radio channel (21). The reference signal may be Positioning Reference Signals (PRS) and/or Common Referencing Signals (CRS), and may be transmitted from a transmitter (22). The wireless device (24) comprises a correlator (100); a reference signal detector (102); a threshold selector (106); and a reference signal analyzer (108). The correlator (100) use a signal received from the radio channel (21) and a replica of the reference signal to provide a correlator output value. The reference signal detector (102) compares the correlator output value with a threshold value to detect presence of a reference signal, and to estimate an arrival time of the reference signal. The threshold selector (106) adapts the threshold value to at least an estimate of a relative amount of noise and interference power in the received signal.

Abstract: A rake receiver having a rake receiver finger operated in a time multiplexed manner to perform the task a plurality of fingers, each of these fingers being a virtual finger allocated to a time slot in an operation cycle of the rake receiver finger, and wherein a buffer is provided for buffering at least one received chip of data, and where a spare virtual finger is provided such that any virtual finger may request extra processing within an operation cycle of the time multiplexed rake receiver finger.

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: A method and apparatus are disclosed for canceling cross-talk in a frequency-division multiplexed communication system. The disclosed frequency-division multiplexed communication system employs multiple carriers having overlapping channels and provides an improved cross-talk cancellation mechanism to address the resulting interference. Bandwidth compression is achieved using n level amplitude modulation in each frequency band. An FDM receiver is also disclosed that decomposes the received broadband signal into each of its respective frequency bands and returns the signal to basehand in the analog domain. Analog requirements are relaxed by removing cross-talk from adjacent R-F channels, from image bands, and minimizing the performance degradation caused by In-phase and Quadrature-phase (I/Q) phase and gain mismatches in modulators and demodulators. The disclosed transmitter or receiver (or both) can be fabricated on a single integrated circuit.

Abstract: Direct sequence spread spectrum communications can use composite codes and can operate at a plurality of different chipping rates. The composite codes can be formed using a plurality of component codes, wherein the component codes can be relatively prime and at least one of the nominal lengths of the component codes can include a plurality of prime number multiplicands. The chipping rate and code length can be reduced by dividing a master rate by one or more of the prime number multiplicands. Symbol timing and time division multiple access timing can be tied to epochs of the component codes.

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: A communications device includes pre-processing circuitry for processing a received wideband complex signal including an undesired narrowband interference component therein, and for determining a frequency of the undesired narrowband interference component. A filter is downstream from the pre-processing circuitry and operable to generate a received wideband complex signal with at least one frequency notch therein to suppress the undesired narrowband interference component. The filter includes a finite impulse response (FIR) filter with L taps to generate N output values, with L>N. A Fast Fourier Transform (FFT) block is downstream from the FIR filter and has a length N so that filter transition regions occur between frequency bins of the FFT block. A notching block is downstream from the FFT block to generate the frequency notch. An Inverse Fast Fourier Transform (IFFT) block is downstream from the notching block and has the length N.

Abstract: In a method of detecting a signal, a control channel associated with a physical channel may be decoded to produce at least one decoding metric. A control channel signal on the control channel may then be detected based on the decoding metric.

Abstract: An adaptive transversal filter having tap weights Wj which are products of corresponding tap coefficients Cj and tap gains Mj is provided. A filter control loop controls all of the tap coefficients Cj such that an error signal derived from the filter output is minimized. One or more tap control loops controls a tap gain Mk such that the corresponding tap coefficient Ck satisfies a predetermined control condition. For example, |Ck| can be maximized subject to a constraint |Ck|?Cmax, where Cmax is a predetermined maximum coefficient value. In this manner, the effect of quantization noise on the coefficients Cj can be reduced. Multiple tap control loops can be employed, one for each tap. Alternatively, a single tap control loop can be used to control multiple taps by time interleaving.

Abstract: Multipath components of transmitted data symbols are received with individual delays and processed by a RAKE having a number of fingers. A delay profile indicating magnitudes for a first number of delay values is provided. Estimated magnitudes for a second number of delay values located between the first number of delay values are calculated by interpolation, and a combined delay profile is provided by combining the magnitudes for the first and second number of delay values. Delay values for peaks in the combined delay profile are determined, and a number of peak delay values (P1, P2, P) comprising the largest peak are selected from the combined delay profile. At least some of the selected peak delay values are provided to the RAKE and assigned to the fingers. This allows a reduction of current consumption and dye area, while still providing delay values with sufficient resolution for the RAKE.

Abstract: System and method for filtering a data packet using a combined filter are disclosed. In one aspect, the method includes receiving a data packet and N filters each comprising a mask and value. The method includes receiving a data packet and N (wherein N is an integer and N>1) filters, each filter comprising a bit mask and corresponding bit values. The method further includes generating a common filter mask and the corresponding bit values by taking the overlapping mask bits among portions of the N filters corresponding to the common filter, the common filter being of a length smaller than each filter. The method further includes applying the common filter mask to the data packet to determine whether there is a match between the filtered data packet and each of the N filters.

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: A method of processing positioning signal constituted by a superposition of individual signals generated by a plurality of emitters, in particular satellite emitters, comprising:—a first step of coarse acquisition of said individual signals, comprising correlation of the received positioning signal with locally generated replicas of said individual signals;—a step of identifying spurious correlation peaks induced by interferences; and—a step of estimating the code delays and the carrier frequency shifts of the acquired individual signals which are not affected by said interferences. According to preferred embodiments of the invention, the method can also comprise:—a refining step of determining more accurate estimates of said code delays and carrier frequency shifts; and—a step of interference cancellation. The method of the invention is particularly suitable to indoor positioning applications.

Abstract: A wireless communication system is provided that detects a frequency burst (FB) through analysis of the autocorrelation function of received signals. The system can accommodate the relatively large frequency offsets that are associated with less expensive reference frequency crystals. The system employs a multi-mode filter including an FB filter and a channelization filter. In one embodiment, the FB filter is employed until an FB is located and then, once the FB is located, the channelization filter is employed to receive signals.

Abstract: An apparatus for detecting an OFDM symbol encoded with a transmitted sequence including a filter having coefficients based on a simplified version of the transmitted sequence is disclosed. A computer program product having code and a wireless communications apparatus for performing the method are also described herein.

Abstract: Exemplary combining weight generation is based on estimating received signal impairment correlations using a weighted summation of interference impairment terms, such as an interference correlation matrix associated with a transmitting base station, and a noise impairment term, such as a noise correlation matrix, the impairment terms scaled by fitting parameters. The estimate is updated based on adapting the fitting parameters responsive to measured signal impairment correlations. The interference matrices are calculated from channel estimates and delay information, and knowledge of the receive filter pulse shape. Instantaneous values of the fitting parameters are determined by fitting the impairment correlation terms to impairment correlations measured at successive time instants and the fitting parameters are adapted at each time instant by updating the fitting parameters based on the instantaneous values.

Abstract: Certain aspects of a method and system for achieving space and time diversity gain are disclosed. Aspects of one method may include modifying a generalization code of at least one pilot channel, to measure signal strengths for each of a plurality of received multipath signals. A portion of the plurality of received multipath signals may be combined based on the measured signal strengths. The signal strengths of the plurality of received multipath signals may be measured on a primary pilot channel by assigning its generalization code to zero. The signal strengths of the plurality of received multipath signals on a secondary pilot channel may measured by assigning its generalization code to a non-zero value.