Abstract: A communications system of the present invention includes a transmitter that is operative for combining an orthogonal Walsh modulation with a minimum shift keying or Gaussian minimum shift keying waveform to form a hybrid communications signal that carries communications data over a constant amplitude waveform that is spread in time and frequency. This communications signal can be transmitted to a RAKE receiver that has a plurality of correlators with output weights formed for processing this hybrid communications signal.

Abstract: A system and method is disclosed for evaluating a data group of oversampled bits to detect edge transitions and for improving use of information available from a sampled data while maintaining acceptable noise rejection. An edge detection system for receiving a serial data stream includes a sampler for collecting a sample pattern from the serial data stream, the sample pattern including a succession of a plurality of data samples from the data stream with the plurality of data samples including multiple samples during a bit time associated with the data stream; a memory, coupled to the sampler, for storing one or more successive sample patterns; and a correlator, coupled to the memory, for producing a sample condition signal using a set of predefined patterns by comparing the stored sampled patterns to the predefined patterns.

Abstract: A method and apparatus for reducing power consumption within a wireless receiver is provided herein. Particularly, the use of partial chip sequence correlation to reduce the average power consumption of a direct sequence spread spectrum (DSSS) wireless transceiver is provided herein. During operation, the receiver will attempt to correlate, or de-spread, less than all chips that constitute a symbol. A partial correlation may be performed on M chips, where M may be much less than N, the number of chips that represent a whole symbol. In a preferred embodiment, the M chips are the first M chips in the symbol.

Abstract: A system and method are provided for determining whether a chipping code from a group of codes is used in a signal. In one embodiment of the invention, a signal is received and each code from the group is correlated with the received signal. The ratio of the highest correlation value to the second highest correlation value is calculated. If the ratio exceeds a threshold, the chipping code may be determined as the chipping code used in the signal. In another embodiment, the ratio of the highest correlation value and the total received power of the signal is calculated. If the ratio exceeds a threshold, the chipping code may be determined as the chipping code used in the signal.

Abstract: A method, system, and computer program product are provided for detecting at least one signal of interest within an input signal. At least one set of samples from the input signal is multiplied by at least one set of samples representing a complex conjugate of the input signal to obtain a series of correlation samples. Sets of one or more consecutive correlation samples are summed to obtain a series of pulse sums. A plurality of non-consecutive pulse sums are integrated to obtain a search value.

Abstract: A method for generating a data signal for synchronizing one or more electrically coupled digital receivers is disclosed. A data signal having a data rate is modulated with a pseudo-noise (PN) code having a data rate greater than the data rate of the data signal. The modulated data signal is demodulated by a receiver using the PN code. A correlation value is generated and is compared to a predetermined value to indicate phase synchronization. If the receiver is in phase synchronization with the transmitter, the received demodulated data signal is passed.

Abstract: Disclosed is a method for performing fast distributed sample acquisition (DSA). A spreader generates a data signal by spreading an incoming data stream over a range of spectrum according to a locally generated first main sequence, and samples the state sample of the main sequence. A sample spreader outputs a first state signal by spreading a symbol according to a locally generated first subsequence. A sample despreader reconstructs the transmitted binary orthogonal symbols by despreading the first state signal obtained from the sample spreader according to a locally generated second subsequence to detect the first main sequence state sample. A despreader compares the state sample obtained from the sample despreader with a locally generated state sample and makes correction on a local SRG to generate a second main sequence having new state. An incoming data stream is reconstructed by despreading the data signal obtained from the spreader according to the second main sequence.

Abstract: In order to perform synchronization detection with high speed, high precision and high reliability and to measure communication quality (propagation characteristics) at high precision and high efficiency, a mobile station (202) includes synchronization detecting portion (221) for detecting synchronization chip timing of channel to be measured, a synchronization chip timing information portion accumulating information of detected synchronization chip timing, a correlation detecting portion (222) deriving a correlation value between spreading code of the channel to be measured and a received signal for performing communication with a base station and measurement of communication quality with taking the detected synchronization chip timing as a reception chip timing, a time series generating portion (223) for generating a time series data of received signal vector after correlation detection, and a communication quality calculating portion (224) for calculating communication quality from generated time series da

Abstract: An apparatus of sequentially decoding CCK codes includes a series of received signal registers used to respectively temporarily save the received signals, a phase selector used to select one numeral from 1, ?1, j or ?j respectively for CCK code of each chip to multiple with the signal register, a series of adders used to sequentially complete adding operation, a series of sequential operation registers used to save values obtained from the sequential selecting operation of the phase selectors and the sequential adding operation of the adders, and a comparing device used to select a maximal value from those saved in the operation registers. The comparing device includes a comparator and a maximum register. According to the invention, the data processing speeds up while the hardware complexity is reduced.

Abstract: A communication apparatus includes an antenna which receives data frames from transmitters; at least one correlator, each of which is associated with a single identification code and detects a frame corresponding to the identification code from the data frames; and a reserved correlator which detects an acknowledge (ACK) frame from the transmitters corresponding to at least one correlator.

Abstract: For each user in a multi-user detection arrangement in a CDMA communications system, a detector (80) provides a limiting function (88) responsive to a combined signal to produce a detection signal, having any of at least three possible values, for supply to a signal regenerator, regenerated signals being subtracted from a received signal in successive detection iterations of the multi-user detection arrangement. A code correlated signal is supplied via an inverse hyperbolic tangent function (84), or is multiplied by a multiplier inverse to an iteration index, to produce a derived signal. The derived signal is added (86) to a representation of a detection result stored from a previous iteration to produce the combined signal. The limiting function can comprise a hyperbolic tangent function.

Abstract: The invention provides methods and apparatus for multiple user detection (MUD) processing that have application, for example, in improving the capacity CDMA and other wireless base stations. One aspect of the invention provides a multiprocessor, multiuser detection system for detecting user transmitted symbols in CDMA short-code spectrum waveforms. A first processing element generates a matrix (hereinafter, “gamma matrix”) that represents a correlation between a short-code associated with one user and those associated with one or more other users. A set of second processing elements generates, e.g., from the gamma matrix, a matrix (hereinafter, “R-matrix”) that represents cross-correlations among user waveforms based on their amplitudes and time lags. A third processing element produces estimates of the user transmitted symbols as a function of the R-matrix.

Abstract: System and method for performing symbol boundary aligned searches of signals. A preferred embodiment comprises a search control unit (such as search control unit 725) that can determine a start and stop condition for a correlation based on a hypothesis, a searcher (such as searcher 705) which includes a multiplexer that can select a subset of samples of a received sequence based on the hypothesis and start and stop conditions. The search control unit can then wait for the occurrence of the start condition and assign the hypothesis to a correlator, which will correlate the subset of samples with a locally generated pseudo-random number sequence based upon the hypothesis.

Abstract: The present invention is directed to a method, program product, and apparatus that determines a signal quality associated with a symbol modulated signal based on a scalar relationship based on at least one of a comparison of plural correlation candidates for a symbol in the modulated signal or a comparison of the vector corresponding to a decided symbol against a reference. In accordance with one aspect of the present invention, a method and apparatus are disclosed which involve determining maximum and next-maximum correlation candidates for a symbol perceived in the modulated signal, calculating the scalar relationship between the maximum and next-maximum correlation candidates, and deriving a signal quality associated with the modulated signal based on the scalar relationship.

Abstract: The present invention is related to a flexible distribution architecture and method for rake receiver of communication system, comprising: a plurality of processing units, further, each processing unit comprises: a plurality of rake receivers, wherein each rake receiver can receive a multi-path signal from its environment and, through a recovery process, outputs a recovered signal therefrom; an combiner, which connects with the plurality of rake receivers and receives a plurality of recovered signals, then further integrates the plural recovered signals which are originated from a same source by an integration process and, consequently, outputs an integrated signal therefrom; a master processing unit, which connects with the plural processing units and, through detecting the signal received, assigns an appropriate number of rake receivers to receive signals, and further the plural integrated signals originated from a same source are integrated by an integration process and, consequently, outputs a compound si

Abstract: In a method and arrangement for detecting a random access channel preamble in a received uplink signal, the uplink signal is received at one or more receive antennas and contains data related to a random access channel preamble. The received uplink signal is subjected to spatial processing and temporal processing in order to detect the random access channel preamble. A best cell portion for communicating with a user may also be determined based on the detected preamble. The best cell portion represents a portion of a cell where a received uplink signal from a user has a highest signal to interference ratio. The detected random access channel preamble is indicative of the best cell portion for communicating with the user.

Abstract: A transmission power control method includes a step (a) of receiving by a receiver a radio wave signal, a step (b) of judging whether a first identification signal is included in the received radio wave signal, a step (c) of detecting a reception electric field intensity of the radio wave signal included in the radio wave signal in the case where the first identification signal is included in the radio wave signal, a step (d) of obtaining a radio wave propagation state between a home station and the station to communicate with by using the reception electric field intensity detected at the step (c) and determining transmission power of the transmission radio wave signal based upon the radio wave propagation state, a step (g) of invalidating the radio wave propagation state obtained upon the previous reception in the case where the interval between an end of communication and a restart of communication is longer than a time determined in advance, a step (e) of superimposing a second identification signal on th

Abstract: The frame words of the preferred embodiment are especially suitable for frame synchronization and/or channel estimation. By adding the autocorrelation and cross-correlation functions of frame words, double maximum values equal in magnitude and opposite polarity at zero and middle shifts are obtained. This property can be used to slot-by-slot, double-check frame synchronization timing, single frame synchronization and/or channel estimation and allows reduction of the synchronization search time. Further, the present invention allows a simpler construction of a correlator circuit for a receiver.

Abstract: A dynamic matched filter bank consists of a plurality of matched filters with either the reference signal for each matched filter changes with the time or the input signal to a matched filter is the received signal modified by a different way for a different matched filter. A receiver employed a set of dynamic matched filter banks in a multi-channel spread spectrum communication system consists of a signal register, a block PN generator, a plurality of spreading sequence generators, a plurality of register arrays, a plurality of multiplier arrays, a plurality of matched filters, a plurality of signal combiners, and a controller. The block PN generator generates a section of PN sequence at the end of every symbol period with feedback logic to shift a block of chips each time. A register array captures each section of PN sequence from the block PN generator and delays it for a symbol period. The rest register arrays are in cascade and delay the section of sequence at each of their inputs by one symbol period.

Abstract: System and method for managing finger and path resources. A preferred embodiment comprises receiving a delay profile, processing paths from the delay profile, placing the processed paths into a plurality of sets based on path criteria, and assigning the placed processed paths to demodulating fingers. A preferred embodiment further comprises the use of historical information on paths in the placing.

Abstract: A method of partial interference cancellation of a received signal that includes a first data component and a second data component is disclosed. The method includes the steps of determining a characteristic of the communication channel, estimating a factor based upon the characteristic, using the factor to cancel the second data component from the signal, and recovering the first data component from the signal.

Abstract: A mobile communication system 1 according to the present invention comprises base station 30 and mobile station 10. The base station 30 sends a pilot symbol sequence known to the mobile station 10, to the mobile station 10, using a plurality of carriers for downward channels, and performs communication with the mobile station 10 while multiplying the channels by frequencywise same scrambling codes every symbol period. The mobile station 10 is provided with a peak detector 17 for calculating cross correlation allowing for a phase difference of the scrambling codes, between frequencywise pilot symbol sequences received from the base station 30, thereby detecting a radio frame boundary.

Abstract: A CDMA demodulation circuit to be adapted to fluctuation of arrival path timing and to obtain good reception characteristics, can be provided. A despreading timing correction control portion controls number of despreading timing correction candidates depending upon result of comparison in a correction value difference calculating portion. An effective path timing judgment portion makes judgment of an effective path timing on the basis of correlation peak information detected by the correlation value difference calculating portion. Respective despreading portions perform despreading at a plurality of timings including a path timing set from the effective path timing judgment portion and despreading timing correction candidates of M points before and after the set path timing.

Abstract: A flexible Fast Walsh Transform circuit provides configurable FWT sizes, and is suitable for use in radio receivers where the received signal may be generated using varying spreading codes and/or varying numbers of multi-codes. Such signal types are commonly encountered in wireless communication systems like those based on the Wideband CDMA (W-CDMA) or IS-2000 (cdma2000) standards, and particularly with the higher data rate provisions of those standards. In one application, a RAKE receiver includes RAKE fingers that each include one of the flexible FWT circuits, such that each finger despreads the received signal using variably sized FWTs in accordance with the characteristics of the received signal. The flexibility in FWT sizing may derive from, for example, the inclusion of separately selectable but differently sized FWT circuits, or from the inclusion of a configurable FWT circuit capable of generating different sizes of FWTs.

Abstract: A parameter estimator for estimating one or more parameter(s) from a signal is described. A correlation function is derived from the signal, and the correlation function analyzed to determine if one or more first peak(s) are present, and, if so, distinguishable from the sidelobe(s) of a second peak. If the one or more first peak(s) are present and distinguishable from the sidelobe(s) of the second peak, the one or more parameter(s) are estimated from the one or more first peak(s). If the one or more first peak(s) are not present, or, if present, are not distinguishable from the sidelobe(s) of the second peak, the one or more parameter(s) are estimated from the second peak. The parameter estimator may be employed in a subscriber station to estimate a parameter such as the time of arrival of one or more base station or sector pilot signals in a wireless communication system.

Abstract: A system for inhibiting a potential interference source in a communications system. The system includes a first mechanism for incorporating a code within a signal. A second mechanism employs the code to decode the signal. A third mechanism for selectively prevents detection by the second mechanism of a subsequent signal employing the code. In a specific embodiment, the third mechanism incorporates a predetermined delay after receipt of the signal by the second mechanism. The predetermined delay is sufficient to prevent detection by the second mechanism of the subsequent signal employing the code. The code is a function of a time value associated with the signal. The subsequent signal incorporates the code and lacks a corresponding accurate time value due to the predetermined delay. Consequently, rebroadcast of the subsequent signal, which is a delayed signal, is less likely to interfere with the system communications.

Abstract: A bus system includes multiple devices and a bus. The bus is connected to each device. Each device may include a type of input/output (I/O) device, such as a random access memory (RAM) or a microprocessor. The bus transfers data between devices. Data of each device may be encoded with a unique orthogonal code. Encoded data of each device may be superimposed onto a bus so as to permit substantially concurrent communication on the bus by each of the devices. Data of each device is decoded by correlating the encoded data with the unique code used to form the encoded data.

Abstract: A method and apparatus for channel estimation in a spread spectrum receiver include processing that begins by despreading a received spread spectrum complex baseband sample utilizing a pseudorandom spreading sequence to produce a despread baseband symbol. The processing continues by filtering the despread baseband symbol to attenuate adverse channel effects based on a channel response estimate to produce a filtered despread baseband symbol. The processing then continues by decoding the filtered despread baseband symbol to produce recaptured data. The processing continues by modulating the recaptured data to produce a remodulated symbol. The processing then continues by producing a reconstructed spread spectrum complex baseband sample from the remodulated symbol based on the pseudorandom spreading sequence.

Abstract: This disclosure is generally directed to communication systems, devices used in communication systems and associated methods which may implement parallel hypothesis search techniques. The disclosed parallel hypothesis search techniques may permit a hypothesis to be dismissed early (i.e., before hypotheses in other searchers have completed their evaluation). Early hypothesis dismissal permits a new hypothesis to be loaded into the searcher while other searchers advantageously continue to evaluate their hypotheses.

Abstract: Systems and techniques are disclosed wherein a gated pilot signal can be acquired by producing a plurality of product values for each of a first and second signal and a generated signal, coherently combining portions of the product values produced from the first signal and noncoherently combining those coherently combined portions to produce a first value, coherently combining portions of the product values produced from the second signal and noncoherently combining those coherently combined portions to produce a second value, and noncoherently combining the first and second values.

Abstract: A power supply system. The power supply system may have a power circuit having a switch and adapted to generate a first output voltage and a second output voltage, depending on the state of the switch. It also includes an output connector coupled to the power circuit, where the output connector includes a plurality of electrical contacts including a first electrical contact and a second electrical contact. A voltage output indicator device is coupled to the first and second electrical contacts. The voltage output indicator device indicates that the power circuit is producing the first output voltage or the second output voltage, so that the user is aware of the voltage being output by the power supply system.

Abstract: One embodiment of the present invention provides a system that facilitates aligning a first signal with a second signal in a manner that optimizes a correlation between the first signal and the second signal. The system starts by receiving a set of signals, including the first signal and the second signal. The system then determines a correlation between the first signal and the second signal. Next, the system adjusts an alignment between the first signal and again determines a correlation between the first signal and the second signal. If the correlation is greater with the alignment adjustment, the system adjusts the alignment between the first signal and the second signal. This process of adjusting the alignment is repeated for different alignments to find an optimal alignment. Hence, the present invention operates effectively for signal sources which may be independently speeding up and slowing down with respect to each other while under surveillance.

Abstract: A channel estimator for determining channel weighting coefficients for a finger of the RAKE receiver. The channel estimator comprises: 1) a first correlator for receiving a first pilot channel signal and correlating the first pilot channel signal with a first pilot channel chip pattern associated with the first pilot channel signal to produce an output comprising a first pilot channel symbol sequence; and 2) a first channel estimation filter capable of receiving the first pilot channel symbol sequence and generating first channel weighting coefficients. The first channel estimation filter minimizes the mean squared error of the channel estimate in the first channel weighting coefficients caused by additive noise and Doppler effects, wherein the mean squared error is minimized across a range of Doppler frequencies from 0 Hz up to a predetermined maximum Doppler frequency.

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

Abstract: Determination of the impulse position in a multipath channel in a noisy environment includes dynamically adjusting a threshold value when making comparisons against a signal property level.

Abstract: A single, common correlation filter (CF) core is provided in a wireless system using CDMA. A plurality of channels with different data rates are provided in the wireless system. The channels provided in the wireless system include the access channel, the maintenance channel, and the traffic channel in which information (e.g., pilot or data symbols or both) is transmitted at the tier 1, tier 2 and tier 3 rates. The data rate for transmitting the information is programmable by digital signal processor (DSP). A user-unique code, such as a PN code, is applied to the information being transmitted in the channels of the wireless system. The information is QPSK modulated and transmitted in any one of the channels at any data rate. The transmitted information is correlated at the smallest data rate (i.e., the tier 1 rate) in the correlation filter (CF) of the wireless system by time multiplexing delayed versions of the PN code to the correlation filter core.

Abstract: A method and device for estimating a target chip index value in a code-division multiple access receiver. The receiver receives signals from a transmitter that uses a plurality of transmitted chips for data transmission through a plurality of multipath channels. As each channel is expressible as a channel impulse response at a given instant in time, the impulse response can be sampled and the samples indexed by a plurality of delay sample indices. The target chip index value can be determined based on the first moment of the delay sample indices over an impulse response.

Abstract: A low data rate wireless channel (control channel) is associated with a high speed wireless channel (data channel). The data channel is divided into discrete code or time slots (access slots), that are unassigned to any particular recipient or user until requested. In the event that a particular user requires a particular resource, access slots are requested through the control channel, allocated to the user, and allocation information is passed back to the requesting user through the control channel. Direction and/or location information associated with the user is ascertained, through messaging with the user or by antenna sensing. This direction/location information is utilized to directionally broadcast requested resources toward the user to increase signal to noise ratios, reduce interference, and enable spectrum reuse within a cell. Optionally, the location information may also be used to adjust the transmitted power to further reduce interference in the cellular network.

Abstract: The present invention provides a method and system for operating a wireless communication system in which received signals from a plurality of antennas are weighted and combined with a beam forming operation to form an output signal. The beam forming operation determines weights adjusted to increase a desired signal power in the output signal while reducing the power in the output signal of out-of-band components. In an embodiment of the present invention, beam forming operations are performed with maximal ratio combining (MRC). Alternatively, a constant modulus algorithm (CMA) can be used for beam forming operations. In an alternate embodiment, improved interference suppression is performed with a novel algorithm referred to as an interference nulling algorithm (INA). The INA receives an error signal which is 180° out of phase with a combination of the channels for individual antennas, referred to as the SUM channel.

Abstract: A technique for receiving an error state in a single chip sequence in a wireless communications network is disclosed. The error state may comprise a Viterbi error state. The error state may be identified as a target code encoded in the single chip sequence, the target code comprising either a code or the complement of the code. The code may comprise a PN-Code. The error state may be identified using a previous mapping of error states from a set of error states to a group of codes, the group of codes comprising a plurality of codes and their complements. The error states in the set of error states in the previous mapping may be uniquely mapped to plurality of codes and their complements in the group of codes.

Abstract: A method of frequency tracking based on recovered data, for use in an automatic frequency control subsystem at the receiver of a mobile station, is disclosed. The frequency tracking mechanism derives frequency error information from the recovered data to determine the adjustment needed at the mobile station's local voltage controlled oscillator in order to track the frequency of the base station.

Abstract: A Rake receiver suitable for receiving, for example, direct sequence CDMA signals, in which the pilot code used to correlate the received signal in each Rake finger (RF1, RF2, RFN) is interpolated prior to the correlation.

Abstract: Dynamic Time Metered Delivery (DTMD) is a unique physical layer communication Method. DTMD uses enhanced time-based techniques to enable and control the flow of more data/Hertz through a variety of transmission media including existing and new copper phone lines, coaxial cable, fiber optic, powerline and wireless RF, Optical and Acoustic, to and from a comprehensive, multi-function customer data gateway. The system measures the transmission parameters as viewed from the “end of the line” and then sends these numerics back to the source which alters the shape of the basic signal structure such that when received at the far end, it will have maximum recognition attributes against interferers and noise. The present system and method add the adaptivity to the line conditions and set a maximum allowable data rate within the subscribed levels of performance.

Abstract: The present invention provides a synchronization establishing device and method for establishing synchronization at a high speed in a receiver. This synchronization establishing device includes a storage unit that accumulates reception data, and a matched filter that reads out the reception data accumulated in the storage unit in parallel and determines a correlation value by obtaining correlation between a common code and the reception data in parallel.

Abstract: A receiving system dynamically searches the communications band for transmissions of messages having the same nominal communications parameters, including the use of the same spreading code, but having potentially different specific frequencies and code-phases. The receiver, which is independent of the transmitters, samples the communications band at each code-phase of the spreading code over a span of downconverted transmission frequencies. When a message element is detected at a particular code-phase and frequency, it is forwarded to a demodulator that demodulates the message and sends it to its intended destination. In a preferred embodiment, a progressive Fourier Transform is used to incrementally determine the power level at each successive code-phase at a given frequency, thereby substantially reducing the time required to search for transmissions at each discrete code-phase.

Abstract: A communication apparatus and method that includes generating a series of successive spread-spectrum signals formed through the concatenation of a direct sequence spread spectrum code with a Doppler Tolerant Polyphase Code (DTPC) is herein disclosed. By transmitting concatenated codes, it is possible to demodulate received sequences that are very long compared to the inverse of the Doppler frequency and/or the local oscillator drift. The method and apparatus may be applied to implement a wireless telecommunication system that efficiently transfers small quantities of data, such as status/telemetry, identification information and/or establishes device location at a low data rate over long distance in challenging radio environments and with low power consumption.

Abstract: Signal processing architectures for direct acquisition of spread spectrum signals using long codes. Techniques are described for achieving a high of parallelism, employing code matched filter banks and other hardware sharing. In one embodiment, upper and lower sidebands are treated as two independent signals with identical spreading codes. Cross-correlators, in preferred embodiments, are comprised of a one or more banks of CMFs for computing parallel short-time correlations (STCs) of received signal samples and replica code sequence samples, and a means for calculating the cross-correlation values utilizing discrete-time Fourier analysis of the computed STCs. One or more intermediate quantizers may optionally be disposed between the bank of code matched filters and the cross-correlation calculation means for reducing word-sizes of the STCs prior to Fourier analysis. The techniques described may be used with BOC modulated signals or with any signal having at least two distinct sidebands.

Abstract: A method and apparatus for multi-path channel characterization in a Direct Sequence Spread Spectrum based wireless communication system is provided. The multipath channel is modeled as a tapped delay line FIR filter with L taps corresponding to L paths. A pre-defined training sequence is transmitted over the multipath channel. The received signal is sampled and cross correlations are computed between the samples obtained and the spreading sequence for various time lags to obtain the symbol boundary. Thereafter, a desired set of L cross correlations for L time lags around the symbol boundary is estimated. For this, all the L possible sets of L cross correlations for L time lags around the symbol boundary are considered. The energy in the cross correlations corresponding to each considered set is calculated. The set of L cross correlations having the maximum energy is selected for tap computation. The tap coefficients are estimated by solving a set of L simultaneous linear equations.

Abstract: Techniques for segmented CDMA searching are disclosed. In one aspect, a searcher comprises a plurality of storage elements selectable for performing a plurality of segmentable search tasks, each storage element operable for storage of and access to state information for one of the plurality of search tasks. In another aspect, a first search task is interrupted in progress, the state information for the first task is stored, a second search task is performed, and the first search task is continued using the stored state information. In yet another aspect, a search task is segmented into smaller search segments, sized to fit within contiguous available time in the searcher. Various other aspects of the invention are also presented. These aspects have the benefit of circuit area and search-time efficiency which translate into reduced costs, increased standby time, increased acquisition speed, higher quality signal transmission, increased data throughput, decreased power, and improved overall system capacity.

Abstract: Clock and data recovery circuitry includes an interleaved sampler having multiple integrators, where at least one of the integrators integrates the input data for at least two unit intervals (UIs). One embodiment includes a four-way interleaved sampler, where each integrator in the sampler integrates the input data for two UIs, where each integrator is sampled at or near the middle of its two-UI integration cycle. In an exemplary 10-GHz system, the reset cycle of each integrator may begin many tens of picoseconds after the data is sampled. Since the signal is sampled near the center of the integration cycle and is not highly proximate to the time of the integrator reset, the latch signal has a window of uncertainty extending into the length of a data bit cell with little possibility of latching erroneous data. The sensitivity of the clock recovery circuitry may be optimized by centering the latch function over the time of highest signal level, thereby maximizing signal-to-noise ratio.