Abstract: Cell search synchronization in spread spectrum communications systems using primary and second synchronization codes with symbol partitioning for shorter coherent combinations (despreading) which are combined non-coherently, and Fourier transform analysis automatically adjusts for phase rotation of the despread sub-symbols.

Abstract: An orthogonal frequency division multiplexed signal transmitting apparatus executes a time-division multiplexing process that inserts a reference signal at a predetermined interval based on reference signal position information into an information signal to be transmitted. The transmitting apparatus generates an orthogonal frequency division multiplexed signal by digital-modulating the time-division multiplexed signal to radiate into a spatial transmission line. An orthogonal frequency division multiplexed signal receiving apparatus receives the signal from the transmitting apparatus to get the reference signal by demodulating the signal.

Abstract: A multi-pass frequency hop timing acquisition correlator that produces a more accurate time estimate from the fast acquisition frequency hop signal is disclosed. The time estimate produced by the multi-pass acquisition correlator is more accurate than the ¼ hop estimate produced by single-pass fast acquisition correlators. The multi-pass frequency hop timing acquisition correlator uses a time estimate generated by a previous pass through the multi-pass frequency hop timing acquisition correlator as a starting point for computing a new, more accurate, time estimate. Thus, the second pass through the multi-pass frequency hop timing acquisition correlator produces a time estimate that is relatively more accurate than the time estimate produced by the first pass. The more accurate time estimate produced by the multi-pass acquisition correlator reduces the hardware and time needed by the direct acquisition process to acquire the M-code.

Abstract: A weight vector of a precedent frame calculated by a weight vector calculator (4) and stored in a memory (3) is applied to a signal received through a plurality of antennas (ANT1, . . . ANTn) for removing an interference wave component. A synchronous position is detected from the signal subjected to removal of the interference wave component by a method of correlation synchronization, and supplied to the weight vector calculator (4). The weight vector calculator (4) executes calculation of a weight vector with the detected synchronous position as a start position. Thus, when signals of the same frequency are received in a CS in an overlapping manner, the synchronous position of a signal received from a desired PS can be correctly specified.

Abstract: A mobile wireless communications device and methods therefore, including receiving a signal (710), storing a portion of the received signal (730), identifying all possible pilot signals by determining slot boundary information for the stored signal portion (720), determining frame boundary information and/or scrambling code information (760) of the stored signal portion by correlating the stored signal portion with the scrambling codes based on the slot boundary information. In other embodiments, the search is performed in real-time without storing the signal.

Abstract: Signals sent from a sender by a code division multiple access communication system are input respectively into first to Mth delay units which are disposed parallel to one another. The correlation is examined in each correlator, and the results of a predetermined number of times of correlation are averaged in each averaging section. Based on this, path detection is carried out in each path detector. The results of path detection are input into a correlator control unit which performs control in such a manner that the number of times of averaging in an averaging section is smaller for a higher correlation value.

Abstract: An incident pulse signal of the ultra wideband type conveys digital information that is coded using pulses having a known theoretical shape. A decoding device includes an input for receiving the incident signal, and for delivering a base signal. A comparator receives the base signal and delivers an intermediate signal representative of the sign of the base signal with respect to a reference. A sampling circuit samples the intermediate signal for delivering a digital signal. A digital processing circuit correlates the digital signal with a reference correlation signal corresponding to a theoretical base signal arising from the reception of a theoretical pulse having the known theoretical shape.

Abstract: A method and system for synchronizing the PN phase of a pseudo-noise (PN) coded signal with a phase of a master PN decade-code is provided. The method includes the steps of associating the master PN decade-code initialization t0 with a first time zone reference date and time and determining an elapsed time t1. The next steps equate the elapsed time t1 to a corresponding phase of the master PN code and synchronize the phase of the PN coded signal with the corresponding phase of the master PN decade-code.

Abstract: A synchronization establishing and tracking circuit for a CDMA base station is composed of a first spreading code generator, a first correlator, a second spreading code generator, a second correlator, and a phase determining circuit. The first spreading code generator generates a first spreading code sequence. The first correlator calculates first correlation between the first spreading code sequence and a first quasi-coherent signal corresponding to a first received signal received by the CDMA base station. The second spreading code generator generates a second spreading code sequence. The second correlator calculates second correlation between the second spreading code sequence and a second quasi-coherent signal corresponding to a second received signal received by the CDMA base station. The phase determining circuit determines a first phase of the first spreading code sequence based on an added quasi-coherent signal to which the first and second quasi-coherent signals are added.

Abstract: Spreading factor (SF) estimation in a code division multiple access (CDMA) spread spectrum system where the SF of the data channel may change on a frame-by-frame basis to reflect a change in the data rate for each corresponding frame. The SF estimation methods despread the data channel for all possible SF values, perform maximal ratio combining (MRC) when resolved multipaths occur, take the absolute value of the MRC results, and average these absolute values over many symbol periods to obtain decision statistics for the various SF's. The SF estimation methods then post-process these decision statistics and make a SF decision.

Abstract: A transmission circuit includes a baseband circuit, spreading section, multiplier, digital modulator, quadrature modulator, and antenna. The baseband circuit generates and outputs at least one transmission data constituted by first and second channel data. The spreading section spreads the transmission data with a spreading code that differs for each transmission channel. The multiplier respectively weights the amplitudes of the first and second channel data by using a combination of two gain factors determined by a transmission data rate. The digital modulator digitally modulates the first and second channel data whose amplitudes are weighted by the multiplier. The quadrature modulator quadrature-modulates the digitally modulated first and second channel data and outputs the data as a transmission signal. The antenna emits the transmission signal output from the quadrature modulator as a radio wave.

Abstract: Briefly, in accordance with an embodiment of the invention, a method and apparatus to transfer information is provided, wherein the method includes transferring information between at least two wireless devices using a waveform that includes a first sinusoidal signal and a second sinusoidal signal, wherein the second sinusoidal signal has more zero-crossings than the first signal and wherein a duration of the first sinusoidal signal is less than a duration of the second sinusoidal signal.

Abstract: A method and system for downlink channelization code allocation or assignment in a Universal Mobile Telecommunication System (UMTS) are presented. The method and system generate an optimal channelization or Orthogonal Variable Spreading Factor Orthogonal Variable Spreading Factor (OVSF) code to be assigned to a new channel through a route having the minimum influence while maintaining the existing or assigned OVSF codes. The inventive method and system leave reserved codes by managing generation and release of the OVSF codes. This prevents situations where the new channel cannot be assigned an OVSF code due to a lack of OVSF codes, even though there is enough available power and enough available channels.

Abstract: A method for assigning codes in an uplink of a synchronous code division multiple access (CDMA) telecommunication system is disclosed. The method for assigning a code in a reverse channel of a synchronous wireless telecommunication system, comprising the steps of: a) at a mobile station, receiving time matching information of a scrambling code from a base station; b) at the mobile station, spreading data frame to be transmitted by an orthogonal code, thereby generating a spread data; and c) at the mobile station, multiplying the spread data by a scrambling code based on the time matching information of the scrambling code, thereby generating an encoded data.

Abstract: A method and apparatus for mitigating multipath interference in a digital signal correlator forms values representative of magnitude or power of a correlation response between a digital signal and a pseudorandom reference code. The earliest peak in the correlation response is then selected as the correct peak to compute a time delay.

Abstract: A spreading system according to an embodiment of the invention spreads two data signals. The system produces a filtered signal that is based on one of the data signals and an output signal that is based on both of the data signals. In one example, a spreading system is used to perform QPSK spreading of two data signals, including separate processing of the two data signals, in a practical manner. Such separate control may include filtering and/or gain control.

Abstract: Described is a system and method for providing a synchronization pattern in a communication system. The method includes generating a synchronization pattern with good randomness properties; packing a signal for transmission with m headers, each header consisting of the synchronization pattern 1/m symbol-time shifted from the previous header; and transmitting the signal. A further method provides for the sampling the transmitted signal with m headers of symbol-time shifted synchronization patterns; and determining symbol timing offset by computing and reordering correlation peaks from the synchronization patterns. A system includes a transmitting system, a receiving system, and a data channel. The transmitted signal includes m headers with 1/m symbol-time shifted synchronization patterns. The receiving system undersamples the transmitted signal with m synchronization patterns to simulate an oversampled synchronization pattern.

Abstract: An improvement for a method and system for tracking a spreading code, used in a code division multiple access (CDMA) system. An input signal has spread-spectrum modulation. The spreading code embedded in the spread-spectrum modulation has a plurality of chips. The input signal is sampled, and half-chip offset samples are formed from the sampled input signal. An even set of the half-chip offset samples are grouped into an early set of samples, and an odd set of the half-chip offset samples are grouped into a late set of samples. Each early set of samples is multiplied by the spreading code c(n+1), c(n+2), . . . , c(n+L), to generate a first plurality of products. L is approximately equal to the number of chips of delay between the earliest and latest multipath signals. A first plurality of sums and magnitudes are computed from the first plurality of products. The first plurality of magnitudes are summed to generate an early signal-energy value.

Abstract: An apparatus comprising a circuit configured to generate a spread spectrum clock signal. The circuit may comprise a voltage controlled oscillator with a gain that may be automatically controlled.

Abstract: Coherent phase-shift keying (“PSK”) radio frequency (“RF”) systems locate a differential decoder (“DE”) close to the transmitter of a first transceiver for transmitting a message to a second transceiver that includes a receiver having has a differential decoder (“DDE”) close to the receiver to aid in the rapid recovery of remnant data of a message hit by a jamming (“J”) pulse received at the receiver of the second transceiver.

Abstract: A radio transmission system including many radio transmitters using frequency hopping carriers to intermittently transmit very short messages indicative of status of stimuli associated with the transmitters. The transmitters transmit transmissions independently of a receiver receiving the transmissions and independent of each other. In operation, radio transmitters transmit messages at varying frequencies at time intervals that can be varied as well. The frequency and time intervals are varied according to patterns that can be determined individually for each transmitter. A receiver holds data indicative of the future transmission frequency and time for each transmitter and updates the data based on the time and the content of the received messages. In addition, a simple method is provided to generate a very large number of orthogonal frequency-time hopping sequences that are individual for each transmitter and based on the transmitter ID.

Abstract: An interleaved coding method can be used in a transmitter, in which the two or more pseudonoise (PN) codes are interleaved to form a longer interleaved code. The method can be used in a transmitter that includes a first code generator generating a first code of n symbols, and a second code generator generating a second code of m symbols, where n and m can be mutually prime, such as m=n+1. An interleave unit is coupled to the first and second code generators, and interleaves the symbols of the first code with the symbols of the second code to output an interleaved code. The interleaved code has a period longer than either of the constituent PN codes, providing for much increased noise tolerance over using the short codes alone, and can be detected at a much lower hardware and time cost than if using a single PN code of equal length.

Abstract: A synchronization establishing method of a mobile station in a mobile communication system is proposed which can reduce the effect of noise or interference, and achieve higher accuracy than conventional method. To enable the mobile station to detect a signal transmitted from a base station, and to establish synchronization to the signal in a mobile communication system in which a synchronization channel is multiplexed periodically into the downlink signal, the mobile station averages, in phase and in complex numbers, correlation values of the synchronization channel over a plurality of periods, followed by detecting the power of them to carrying out peak detection.

Abstract: Burst transmissions in a burst-type communication system include a preamble synchronization sequence which allows detection and synchronization a burst transmission while at the same time providing information to a receiver, for example, on the subsequent burst payload data. Each burst transmission includes a preamble synchronization sequence which is one of a plurality of predetermined allowed preamble sequences in the system, according to the information desired to be transmitted. The system may also use differential encoding and decoding to eliminate the effects of frequency uncertainty. In that case, the allowed preamble sequences may be such that, after differential decoding, they differ from one another only by a polarity inversion such that a single matched filter may be used to detect two preamble sequences.

Abstract: In one embodiment, the invention is directed toward methods for estimating the power of a received signal encoded with both pilot and non-pilot symbols. The method may include separately accumulating the pilot symbols and the non-pilot symbols and then estimating signal power by calculating a weighted sum of the accumulated pilot and non-pilot symbols. In this manner, a more accurate estimate of the power of the received signal can be obtained.

Abstract: A GPS receiver receives GPS spread spectrum communication signals subject to carrier demodulation and code phase autocorrelation using tightly coupled Kalman filter residual estimation based on Ricatti matrix computation for generating code phase errors and carrier phase errors for improved code phase tracking and carrier phase tracking in feedback loops for use in navigation systems.

Abstract: The invention relates to a method for acquiring a receiver (1) into a code modulated spread spectrum signal received by the receiver (1). In the method at least one replica code (r) is used which corresponds to a code used with the modulation having a pre-determined number of chips, and an examination phase is performed, in which a frequency shift of the signal within a selected frequency area is examined, and a code phase of the code used with the modulation is examined. In the method the frequency shift examination is divided into a first estimation phase and a second estimation phase, wherein in the first estimation phase the selected frequency area is divided into a first set of frequencies, and in the second estimation phase a second set of frequencies is examined nearby each frequency of the first set of frequencies.

Abstract: A synchronization data detecting unit is provided in a communication system for detecting predetermined synchronization data. The synchronization data are sent in a transmission frame in a communication signal of the communication system. The synchronization data include a sequence of identical binary symbols which are transmitted after scrambling. The synchronization detection unit comprises a descrambler for descrambling the received communication and for producing an output data sequence having multi-level signal values. The multi-level signal values of the descrambler output are smoothed in a filter unit. The smoothed signal is compared with a predetermined threshold value. If the smoothed signal exceeds the predefined threshold value, a detection of said synchronized data is indicated.

Abstract: A method of optimizing the search for cells in a mobile telecommunication network comprising a plurality of cells, each cell accommodating one base station exchanging synchronization data with a mobile device UE via a channel SCH, so as to allow subscribers' mobile devices to perform measurements on at least one cell adjacent to the current cell for retrieving a scrambling code specific to the adjacent cell. The method has a step of applying a digital filtering to measurement samples collected in a plurality of time windows so as to give a major weight to measurements performed in the most recent time windows.

Abstract: A method and apparatus for computing a convolution between an input GPS signal and a C/A code reference by generating the convolution result in real time without storing unprocessed signal samples. The apparatus comprises a vector multiplier running at high speed to achieve the same result as a vector multiplier sized to process an entire epoch. Additionally, the input samples to, and the output samples of, the vector multiplier can be quantized to reduced circuit complexity.

Abstract: According to the present invention a received Direct Sequence Code Division Multi-Access (DS-CDMA) signal is differentially decoded at the chip level. A number of signaling schemes can be used in the invention including (1) an ON/OFF signaling scheme in which a pseudo noise number (PN) code is sent only in response to one data bit value, and no signal is sent in response to the other bit value; (2) a Two Code signaling scheme in which bit values of 1 triggers a first PN code to transmitted, and a bit value of 0 triggers a second PN code to be transmitted; and (3) an M-ary signaling method in which a plurality of data bit patterns respectively, trigger a plurality of PN codes to be transmitted. After differential decoding the received signal is despread using one or more PN codes, that can be vector sums of two or more PN codes.

Abstract: A receiver for a spread spectrum communication system includes an acquiring circuit that periodically acquires a plurality of signals received via a plurality of paths from a transmitter. The receiver also includes a plurality of tracking circuits that track the synchronization of a predetermined number of signals among the plurality of signals acquired by the acquiring circuit. The receiver additionally includes a judging circuit that judges whether present and past propagation conditions of the predetermined signals tracked by the plurality of tracking circuits are good or bad. A selecting circuit is included in the receiver to select the predetermined number of signals from the plurality of signals acquired by the acquiring circuit, based upon the present and past propagation conditions of the signals judged by the judging circuit, to allow the plurality of tracking circuits to track the predetermined number of signals selected by the selecting circuit.

Abstract: A synchronizing circuit synchronizes a predetermined code with first and second codes different in phase, include: a code generating part outputting phase-shifted code shifted in phase by a predetermined number of chips from the predetermined code; a first correlation detecting part detecting a correlation between the phase-shifted code from the code generating part and the first code; a second correlation detecting part detecting a correlation between the phase-shifted code from the code generating part and the second code; and a code shifting part shifting the phase of the phase-shifted code from the code generating part by a predetermined number of chips according to the detection results of the first and second correlation detecting parts.

Abstract: A PN sequence acquisition device for a multicarrier CDMA mobile communication system including M (where M is a natural number) despreaders, each for multiplying BS generated PN sequences included in M carrier receiving signals by a local PN sequence of an nth (1?n?N, where n and N are natural numbers) time hypothesis in a predetermined integrating period; M correlators, each corresponding to a corresponding one of the M despreaders and each for calculating detection energies depending on correlations between the BS generated PN sequences of the corresponding one of M carrier receiving signals and the local PN sequence of the nth time hypothesis; a combiner for combining the detection energies corresponding to the local PN sequence of the nth time hypothesis for the M carrier receiving carriers; a controller for comparing the combined detection energy of the M carrier receiving signals, output from the combiner, with a threshold value; and N acquisition circuits including an nth local PN generator for providin

Abstract: A multiple phase shift keying (MPSK) spread spectrum communications receiver uses weighted correlation techniques for carrier recovery and tracking. The receiver includes three subsystems: a synchronization system, a carrier tracking system, and a data demodulation system. To demodulate the received signal, the receiver requires a carrier frequency that matches the frequency of an associated transmitter as well as the sampling (or chip) and symbol clocks that are synchronized with those of the transmitter. In the disclosed receiver, the carrier tracking subsystem continually tracks the carrier frequency of the received signal using a tracking scheme that uses weighted correlation techniques. The weighted correlation technique combines signals from two correlator modules, an R-correlator module and a W-correlator module, to generate the correlation output. The R-correlator is similar to conventional correlators. The W-correlator, however, is unlike conventional correlators.

Abstract: A transmitter outputs a radio signal formed from a first baseband signal incorporating a synchronization signal. The recipient obtains a second baseband signal from the received radio signal, detects the synchronization signal in a portion of the second baseband signal in order to compute synchronization parameters and/or parameters for estimating a radio transmission channel, and uses the computed parameters to demodulate another portion of the second baseband signal and extract the transmitted information from it. The synchronization signal contains a synchronization pattern selected by the transmitter on the basis of signalling information to be supplied to the second station. The receiver searches several patterns in the second baseband signal in order to obtain the signalling information depending on the detected pattern.

Abstract: In a radiocommunications system having physical channels each including at least one logical channel, the invention proposes transmitting both the means for acquiring and tracking synchronization and the system information addressed to user stations in a single logical channel referred to as the “synchronization” channel. For this purpose, the synchronization channel carries a repeated detection word (1) together with system information (2) between repeats of the detection word. The system information is subjected to spreading prior to being transmitted over the synchronization channel. The invention makes it possible to limit the amount of system resources that are devoted to providing the functions of synchronization and of broadcasting system information.

Abstract: A vestigial side band (VSB) synchronization (sync) signal detection circuit and method of generating a VSB sync signal is described. The circuit may include means for generating a first control signal related to sync signal generation, based on receipt of a selected one of an input first data signal and input second data signal, and means for generating a position signal containing information regarding positions of a next field sync and segment sync signals. The circuit may also include a correlator for generating a sign signal to determine a sign of the field sync signal, and a generator for generating a plurality of distinct types of sync signals based on the control signal, position signal and sign signal.

Abstract: A subscriber unit receives a plurality of first spread spectrum signals. Each first spread spectrum signal has a first code. An impulse response of multipath components of each received first spread spectrum signal are analyzed to determine a first received component of that received first spread spectrum signal. In one embodiment, for each received first spread spectrum signal, a second spread spectrum signal having a second chip code time synchronized to the first received component of that received first spread spectrum signal is transmitted. In another embodiment, a code timing difference is determined between the first received components of the received first spread spectrum signals. The code timing difference is transmitted.

Abstract: A threshold tracking loop (TTL) (400) for detecting the time of arrival of a spread spectrum wireless communication signal includes a pseudo-noise (PN) generator (440) for generating a receive PN code for use in spread spectrum decoding and a series of time delay units (401-408) for adjusting a phase offset of the PN code. A first PN despreader (423) is coupled to the time delay units and PN generator for despreading an early pilot signal (413). A second despreader (425) is coupled to the time delay units and PN generator for despreading a late pilot signal (415). A first comparison circuit (443) is coupled to the first PN despreader for comparing a signal value of the early pilot signal with a preselected threshold value (322) and for advancing the PN code phase offset if the early signal value is greater than the threshold value.

Abstract: A method and a device are provided for acquiring synchronization to a received digital signal. The signal consists of consecutive frames with a frame synchronization pattern distributed over a significant part of a frame. A number of blocks of constant length (303) are received (302) and a passage is selected (304) from the same location within each received block. A regularly occurring bit value is observed (305, 306) at a constant bit position within the selected passages. As a response to an observed regularly occurring bit value, the corresponding position in the received digital signal is used (308, 309) as a starting point, and the rest of the distributed frame synchronization pattern is located within the received digital signal.

Abstract: A device and a method for equalizing data delays in a multiplicity of serial input data streams switched by a switching network in a telecommunication switching system, wherein the multiplicity of data word synchronization units are used for synchronizing a multiplicity of input data streams at a data word level into a multiplicity of synchronized parallel input data streams.

Abstract: Terminal transmission method and the received signal model are used to develop two methods that estimate the starting time vicinity associated with a random access channel (RACH). First of said methods, called In*Qn RACH starting time vicinity estimation (STVE), multiplies the In and Qn branches of a sample and exacts the starting time of a preamble signal from the peak output of the phase metrics expression (for both even and odd periodicity). The second method, called (In+jQn)2 RACH STVE, performs a square operation on the received complex signal and calculates the peak output of the corresponding phase metric to extract the exact starting time of a preamble signal.

Abstract: A sychronization circuit comprising an analog feedback shift register for generating an internal sequence which is synchronized with an external sequence containing repetitions of a fundamental sequence has a feedback circuit which, for the formation of a new value of a fundamental sequence, combines at least two values (x1,x2) stored in the shift register according to a feedback function (f(x1,x2)), which is then scaled with a factor k, 0.9<k<0.99. The synchronization behaviour is improved, especially in the case of signals with strong background noise, by using a feedback function which is substantially linear in the sectors defined by the signs of the arguments and whose sign corresponds to that of the negative of the product of the negative arguments and whose magnitude is 1 if the magnitudes of the arguments are each 1. A function which meets these requirements and has proved useful is f(x1, . . . ,xm)=−sig((−x1)· . . .

Abstract: A GPS receiver comprises, for each satellite, synchronization circuits for local generation of an internal sequence corresponding to the external sequence derived from the received signal and synchronized with said sequence, which circuits each comprise an analog shift register (25), fed back via a feedback circuit (26), a gain block (27) and an adder (24), for generating the first of m-sequences generating a Gold sequence, and a memory (29) which contains the elements of the second generating m-sequence, which can be read out with a determinative set derived from the values stored in the shift register (25) as address. In a logic element (23), the value read out is logically combined with the next element of the external sequence for generating a value substantially corresponding to the next element of the first m-sequence, and the result is superposed with the feedback value in the adder (24).

Abstract: A method and system for frame synchronization in a digital data transmission. A synchronization word is selected that is suitable for good correlation in a receiver detector. Either traffic bits or control bits are interleaved within the synchronization word in a predetermined pattern that is fixed for consecutive frames. The position of the sync word is varied from frame-to-frame. Also, the interleaved bits that are either traffic or control bits varies substantially between consecutive frames.

Abstract: A loop error detector for use in a Pseudo Noise (PN) code timing tracking loop is disclosed. A first multiplexer receives an early I-channel signal and an early Q-channel signal, and alternately selects the received early I and Q-channel signals at a ½-chip period. A first accumulator accumulates the early I and Q-channel signals multiplexed by the first multiplexer for a specific chip period. A second multiplexer receives a late I-channel signal and a late Q-channel signal, and alternately selects the received late I and Q-channel signals at a ½-chip period. A second accumulator accumulates the late I and Q-channel signals multiplexed by the second multiplexer for the specific chip period. An operator calculates a sum and a difference of the early and late I-channel signals accumulated by the first and second accumulators, calculates a sum and a difference of the early and late Q-channel signals, and multiplies the sums by the differences.

Abstract: A base station transmits a first spread spectrum signal having a first code. It receives and analyzes an impulse response of multipath components of a second spread spectrum signal having a second code to determine a first received component. The second signal is time synchronized with the first spread spectrum signal. A distance determination is made based on in part a timing difference between the second code of the received second signal and the first code of the base station's transmitted first signal and the determined first received components for that base station's received second signal.

Abstract: A device tracks multipath components of a spread-spectrum signal. The spread-spectrum signal has an associated chip code sequence. The device receives multipath components of the spread-spectrum signal. A first and second plurality of multipath components are despread about a center code phase. The first plurality is a sequence of multipath components prior to the center code phase and the second plurality is a sequence of multipath components after the center code phase. A first and second combined energy is determined from the first and second plurality of multipath components. A tracking delay is calculated based on a difference between the first and the second combined energies. The center code phase is adjusted by said tracking delay.

Abstract: Methods for generating code sequences that have rapid acquisition properties and apparatus which implement the methods by processing spreading codes on in-phase and quadrature channels. A first method combines two or more short codes to produce a long code. This method may use many types of code sequences, one or more of which are rapid acquisition sequences of length L that have average acquisition phase searches r=log2L. Two or more separate code sequences are transmitted over the complex channels. If the sequences have different phases, an acquisition may be done by acquisition circuits in parallel over the different code sequences when the relative phase shift between the two or more code channels is known. When the received length L codes or the length L correlation codes used to find the phase of the received codes have a mutual phase delay of L/2, the average number of tests to find the code phase of the received code is L/4.