WO1996004716A1 - Method and apparatus for performing code acquisition in a cdma communications system - Google Patents

Method and apparatus for performing code acquisition in a cdma communications system Download PDF

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Publication number
WO1996004716A1
WO1996004716A1 PCT/US1995/008659 US9508659W WO9604716A1 WO 1996004716 A1 WO1996004716 A1 WO 1996004716A1 US 9508659 W US9508659 W US 9508659W WO 9604716 A1 WO9604716 A1 WO 9604716A1
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Prior art keywords
despread
sequences
signal
output
values
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Application number
PCT/US1995/008659
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French (fr)
Inventor
Todd R. Sutton
Original Assignee
Qualcomm Incorporated
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Filing date
Publication date
Application filed by Qualcomm Incorporated filed Critical Qualcomm Incorporated
Priority to MX9601211A priority Critical patent/MX9601211A/en
Priority to AU30958/95A priority patent/AU687228B2/en
Priority to BR9506273A priority patent/BR9506273A/en
Priority to JP8506511A priority patent/JP3040481B2/en
Priority to DE69533540T priority patent/DE69533540T2/en
Priority to EP95926654A priority patent/EP0721703B1/en
Priority to AT95926654T priority patent/ATE277458T1/en
Priority to CA002172370A priority patent/CA2172370C/en
Publication of WO1996004716A1 publication Critical patent/WO1996004716A1/en
Priority to FI961294A priority patent/FI114593B/en
Priority to HK98116179A priority patent/HK1015197A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H04B1/7073—Synchronisation aspects
    • H04B1/7075—Synchronisation aspects with code phase acquisition
    • H04B1/70754—Setting of search window, i.e. range of code offsets to be searched
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H04B1/7073—Synchronisation aspects
    • H04B1/7075—Synchronisation aspects with code phase acquisition
    • H04B1/70755—Setting of lock conditions, e.g. threshold
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H04B1/7073—Synchronisation aspects
    • H04B1/7075—Synchronisation aspects with code phase acquisition
    • H04B1/7077—Multi-step acquisition, e.g. multi-dwell, coarse-fine or validation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B2201/00—Indexing scheme relating to details of transmission systems not covered by a single group of H04B3/00 - H04B13/00
    • H04B2201/69—Orthogonal indexing scheme relating to spread spectrum techniques in general
    • H04B2201/707—Orthogonal indexing scheme relating to spread spectrum techniques in general relating to direct sequence modulation
    • H04B2201/70701—Orthogonal indexing scheme relating to spread spectrum techniques in general relating to direct sequence modulation featuring pilot assisted reception

Definitions

  • Figure 4 is an illustration of the energy versus chip offset for the zoom window of the present invention.
  • searcher controller 18 may be implemented in hardware using a microprocessor or micro-controller or alternatively in software.
  • Block 92 the calculated energy values for the small window are compared to the validation threshold value (THV). If in Block 92, there are calculated energy values in the small window which exceed the validation threshold then the flow proceeds to block 94 where a counter variable is set to zero and then the flow proceeds back to block 88 and the flow continues as previously described. If in Block 92, there are no calculated energy values in the small window which exceed the validation threshold then the flow proceeds to block 96 where a counter variable is incremented and then the flow proceeds back to block 98 which checks if the validation test has failed twice in a row. If the validation test has failed Vf times in a row, then the flow proceeds to block 80 and a new large window is scanned. If the validation test has not failed twice in a row, then the flow proceeds to block 88 and the operation continues as described previously.
  • TSV validation threshold value

Abstract

A novel and improved method of acquisition in a spread spectrum communication system is presented. In the present invention, a large window of PN chip offset hypotheses are searched which are generated by a PN sequence generator (20) under the control of a searcher controller (18). The energy of the despread sequence which is despread by a despreader (6) is found that might indicate the presence of the pilot signal in a threshold comparer (16) having one of the chip offsets of the large search window, then a search of a subset of offset hypotheses, or small window, is searched under the control of searcher controller (18).

Description

Method and Apparatus for Performing Code Acqui sition i n a CDMA Communications System
BACKGROUND OF THE INVENTION
I. Field of the Invention
The present invention relates to spread spectrum communications. More particularly, the present invention relates to a novel and improved method and apparatus for acquisition in spread spectrum communication environment.
II. Description of the Related Art
The use of code division multiple access (CDMA) modulation techniques is one of several techniques for facilitating communications in which a large number of system users are present. Other multiple access communication system techniques, such as time division multiple access (TDMA) and frequency division multiple access (FDMA) are known in the art. However, the spread spectrum modulation technique of CDMA has significant advantages over these modulation techniques for multiple access communication systems. The use of CDMA techniques in a multiple access communication system is disclosed in U.S. Patent No. 4,901,307, issued February 13, 1990, entitled "SPREAD SPECTRUM MULTIPLE ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERS", assigned to the assignee of the present invention, of which the disclosure thereof is incorporated by reference herein.
CDMA by its inherent nature of being a wideband signal offers a form of frequency diversity by spreading the signal energy over a wide bandwidth. Therefore, frequency selective fading affects only a small part of the CDMA signal bandwidth.
Space or path diversity is obtained by providing multiple signal paths through simultaneous links from a mobile user through two or more cell- sites. Furthermore, path diversity may be obtained by exploiting the multipath environment through spread spectrum processing by allowing a signal arriving with different propagation delays to be received and processed separately. Examples of the utilization of path diversity are illustrated in U.S. Patent No. 5,101,501, issued March 31, 1992, entitled "SOFT HANDOFF IN A CDMA CELLULAR TELEPHONE SYSTEM", and U.S. Patent No. 5,109,390, issued April 28, 1992, entitled "DIVERSITY RECEIVER IN A CDMA CELLULAR TELEPHONE SYSTEM", both assigned to the assignee of the present invention and incorporated by reference herein. The deleterious effects of fading can be further controlled to a certain extent in a CDMA system by controlling transmitter power. A system for cell-site and mobile unit power control is disclosed in U.S. Patent No. 5,056,109, issued October 8, 1991, entitled "METHOD AND APPARATUS FOR CONTROLLING TRANSMISSION POWER IN A CDMA CELLULAR MOBILE TELEPHONE SYSTEM", Serial No. 07/433,031, filed November 7, 1989, also assigned to the assignee of the present invention. The use of CDMA techniques in a multiple access communication system is further disclosed in U.S. Patent No. 5,103,459, issued April 7, 1992, entitled "SYSTEM AND METHOD FOR GENERATING SIGNAL WAVEFORMS IN A CDMA CELLULAR TELEPHONE SYSTEM", assigned to the assignee of the present invention, of which the disclosure thereof is incorporated by reference herein.
The aforementioned patents all describe the use of a pilot signal used for acquisition. The use of a pilot signal enables the mobile station to acquire local base station communication system in a timely manner. The mobile station gets synchronization information and relative signal power information from the received pilot -signal.
In an ideal system where the hardware set up time is zero, a search window of one hypothesis would be ideal. However, because it takes time to set up the hardware to conduct searches windows of hypotheses are tested. The longer the time required to set up the hardware, the larger the necessary window size. In complex systems a searcher is required to search a window of many hypotheses and upon finding a candidate synchronized sequence, will repeat the search over the window a predetermined number of times to verify the synchronization. This process requires an unacceptably long acquisition time. The present invention provides a method and apparatus for accelerating the time required to acquire a the pilot signal in a mobile communications system.
SUMMARY OF THE INVENTION
The present invention is a novel and improved method and apparatus that reduces the mobile unit forward link acquisition time. It is an advantage of the present invention to minimize the total time for acquisition by speeding up the search methodology without incurring excessive penalties for false acquisition.
A method for determining and verifying the phase of a pilot channel in a spread spectrum communication system comprising the steps of determining a set of calculated energy values for a first predetermined large window set of PN sequence hypotheses; comparing the set of calculated energy values against a first threshold value; determining a second set of calculated energy values for a predetermined small window set of PN sequence hypotheses wherein the small window PN sequence hypotheses are a subset of the large window set of PN sequence hypotheses when at least one energy value of the set of calculated energy values exceeds the first threshold value; and determining the phase of the pilot channel in accordance with the second set of calculated energy values.
BRIEF DESCRIPTION OF THE DRAWINGS
The features, objects, and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters identify correspondingly throughout and wherein:
Figure 1 is a block diagram of the present invention; Figure 2 is an illustration of the energy versus chip offset for a fixed window;
Figure 3 is a flowchart illustrating a fixed window size implementation of the searcher algorithm;
Figure 4 is an illustration of the energy versus chip offset for the zoom window of the present invention; and
Figure 5 is an illustration of the energy versus chip offset for the zoom window implementation of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In a spread spectrum communication system, a pilot signal is used to synchronize a mobile station in phase and frequency to the transmissions of a base station. In the exemplary embodiment, the spread spectrum communication system is a direct-sequence spread spectrum communication system. Examples of such systems are discussed in U.S. Patent No. 5,056,109 and U.S. Patent No. 5,103,459. In a direct-sequence spread spectrum communication system, the transmitted signals are spread over a frequency band greater than the minimum bandwidth necessary to transmit the information by modulating a carrier wave by the data signal, then modulating the resulting signal again with a wideband spreading signal. In a pilot signal, the data can be looked at as an all ones sequence.
The spreading signal is typically generated by a linear feedback shift register, the implementation of which is described in detail in the aforementioned patents. The spreading signal can be viewed as a rotating phasor of the form:
s(t) = Ae"**- (1)
In order to acquire, the mobile station must synchronize to the received signals from the base station in both phase, φ, and in frequency, ω. The object of the searcher operation is to find the phase of the received signal, φ. After finding the phase of the spreading signal, φ, the frequency is found in using a demodulation element that has hardware for both phase and frequency tracking. The method by which a mobile finds the phase of the received signal is by testing a set of phase hypotheses, referred to as a window and determining if one of the hypothetical phase hypotheses, also referred to as offset hypotheses, is correct.
Turning now to the drawings, Figure 1 illustrates the apparatus of the present invention. Upon power up, a spread spectrum signal is received at antenna 2. The objective of the apparatus is to gain synchronization between pseudorandom noise (PN) sequences generated by PN sequence generator 20 and the received spread spectrum signal which is spread by identical PN sequences of unknown phase.
In the exemplary embodiment, both the modulator that spreads the pilot signal and PN generator 20 are a maximal length shift register which generate the PN code sequences for spreading and despreading the pilot signal respectively. Thus, the operation of obtaining synchronization between the codes used to despread the received pilot signal and the PN spreading code of the received pilot signal involves determining the time offset of the shift register.
The spread spectrum signal is provided by antenna 2 to receiver 4. Receiver 4 downconverts the signal and provides the signal to despreading element 6. Despreading element 6 multiplies the received signal by the PN code generated by PN generator 20. Due to the random noise like nature of the PN codes the product of the PN code and the received signal should be essentially zero except at the point of synchronization.
However, due to a lack of synchronization on a chip level and due to introduced noise this is not the case, which gives rise to false alarm situations where the mobile station may believe that it has successfully acquired the pilot signal but in realty it has not. In order to give higher certainty to the determined condition of successful lock, the test is repeated a number of times. The number of times the test is repeated is determined by searcher controller 18. Searcher controller 18 may be implemented in hardware using a microprocessor or micro-controller or alternatively in software.
Searcher controller 18 provides an offset hypothesis to PN generator 20. In the exemplary embodiment, the received signal is modulated by quadrature phase shift keying (QPSK), so PN generator provides a PN sequence for the I modulation component and a separate sequence for the Q modulation component to despreading element 6. Despreading element 6 multiplies the PN sequence by its corresponding modulation component and provides the two output component products to coherent accumulators 8 and 10. Coherent accumulators 8 and 10 sum the product over the length of the product sequence. Coherent accumulators 8 and 10 are responsive to signals from searcher controller 18 for resetting, latching and setting the summation period. The sums of the products are provided from summers 8 and 10 to squaring means 14. Squaring means 14 squares each of the sums and adds the squares together.
The sum of the squares is provided by squaring means 12 to non¬ coherent combiner 14. Noncoherent combiner 14 determines an energy value from the output of squaring means 12. Noncoherent accumulator 14 serves to counteract the effects of a frequency discrepancy between the base station transmit clocks and the mobile station receive clock and aids in the detection statistic in a fading environment. If one knows that the frequency of the two clocks are exactly the same and that there is no deep fades then the ideal approach is to integrate the sequence over the entire accumulation period in the form:
Figure imgf000007_0001
(2) , where PNI (n) and PNQ(n) can be ±1.
If, however, there is a probability of frequency mismatch or fading, then the correlator sacrifices some of its detection statistic in order to have a more robust correlation technique of the form:
Figure imgf000008_0001
(3)
Searcher controller 18 provides the value M to noncoherent accumulator 14.
Noncoherent accumulator 14 provides the energy signal to comparison means 16. Comparison means 16 compares the energy value to predetermined thresholds supplied by searcher controller means 18. The results of each of the comparisons is then fedback to searcher controller 18. Search controller 18 examines the comparisons and determines whether the window contains likely candidates for the correct offset then the widow is rescanned in accordance with the method of using a zoom window.
In order to illustrate the benefits of using the zoom window technique an example of the method using a fixed window size is provided. Figure 2 illustrates a graph of the energy values versus the chip time hypothesis. In the exemplary embodiment a window contain 56 chip hypotheses. The window illustrates the use of a two level threshold test. The thresholds denoted are detection threshold, and validation threshold.
Figure 3 illustrates a conventional method used for scanning windows of a fixed number of hypotheses. The flow starts in block 40, where the operation described in relation to Figure 1 is performed to give comparison results indicated in Figure 2. If the window is "swept" and no hypothesis's energy exceeds the detection threshold (THM) block 42, then searcher controller 18 would begin sweeping the next window blocks 47 and block 40.
However, if there are points on the calculated energy curve which do exceed the detection threshold (THM), then the flow proceeds to the validation phase in block 44. In block 44, the same large window is swept again, and this time the calculated energy is compared against the lower threshold value, validation threshold (THV). If in block 42 the maximum energy detected does not exceed the threshold, then a next large window is swept in blocks 47 and 40. The flow proceeds to block 48 which determines if validation for twenty consecutive windows has occurred. If fewer than N validation tests, where for example N equals twenty, have been conducted then the flow proceeds to block 44 and the large window is swept again. However, after N consecutive successful validation tests then the pilot is determined to be acquired. Now turning to Figure 4, the calculated energy curve is illustrated and the use of the zoom window of the present invention is illustrated. When a peak is detected, the searcher controller zooms in on that peak and tests hypotheses in a smaller set close to the hypothesis that gave rise to the detected peak. Turning to Figure 5, a flowchart illustrating the method by which the searcher of the present invention operates. In the improved method of the present invention a three stage acquisition technique is used. In block 80, the large window is swept. Searcher controller 18 examines the comparison results to determine if there is a peak greater than Detection Threshold (THM). If no peak is detected greater than THM then the flow returns to block 80 and a new window is swept.
When a peak greater than THM is found in a large window, then the flow proceeds to block 84. This time only a sweep in the smaller set of hypotheses around the detected peak is performed. This smaller set of hypotheses is illustrated in Figure 4 as the small window. The use of the small window for the second verification is to reduce the acquisition time by greatly reducing the time to test for false alarm, the state wherein the mobile initially believes it has narrowed in on the phase, but in reality has not. The time it takes to perform this second test is reduced proportionally to the ratio between the number of hypotheses in the small window versus the number of hypotheses in the large window. Noncoherent accumulations are performed in on the data from this small window search in order to have a better operating characteristic.
Then in block 86, if there is energy greater than Detection threshold 2 (THM2), the search enters the validation phase. If no energy greater than the threshold THM2 is found then the flow returns to block 80 and a new large window is searched.
If in block 86, it is determined that there is a calculated energy value greater than threshold 2 (THM2), then the flow proceeds to block 88. There are three conditions under which validation is stopped: (1) the sweep fails Vf in a row, (2) the frequency estimate doubles back on itself from on 100ms sample to the next, or (3) determine that the pilot has been acquired. In validation, the signal at the peak is demodulated. In block 88, the received signal is demodulated in accordance with the hypothesis of the peak. The results of the demodulated signal are analyzed to determine if they are in lock, and if so then acquisition is complete. If the demodulated results indicate that the signal is not in lock, then the flow proceeds to block 92.
' In Block 92, the calculated energy values for the small window are compared to the validation threshold value (THV). If in Block 92, there are calculated energy values in the small window which exceed the validation threshold then the flow proceeds to block 94 where a counter variable is set to zero and then the flow proceeds back to block 88 and the flow continues as previously described. If in Block 92, there are no calculated energy values in the small window which exceed the validation threshold then the flow proceeds to block 96 where a counter variable is incremented and then the flow proceeds back to block 98 which checks if the validation test has failed twice in a row. If the validation test has failed Vf times in a row, then the flow proceeds to block 80 and a new large window is scanned. If the validation test has not failed twice in a row, then the flow proceeds to block 88 and the operation continues as described previously.
The previous description of the preferred embodiments is provided to enable any person skilled in the art to make or use the present invention. The various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without the use of the inventive faculty. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. In a direct sequence spread spectrum communication system, a method for determining PN sequence synchronization, comprising the steps of: calculating a first set of signal correlation energy values for a first set of temporally offset PN sequences; comparing said first set of signal correlation energy values against a first threshold value; selecting a second set of PN sequences in accordance with said first set of signal correlation energy values; calculating a second set of signal correlation energy values for said second set of PN sequences, wherein said second set of PN sequences are a subset of said first set of PN sequences; and selecting said synchronized PN sequence from said second set of PN sequences in accordance with said second set of signal correlation energy values.
2. The method of Claim 1 further comprising the step of comparing said second set of signal correlation energy values against a second threshold value.
3. The method of Claim 2 further comprising the step of demodulating a received signal in accordance with said selected synchronized PN sequence.
5. The method of Claim 1 further comprising the step of receiving and downconverting a broadcast signal to provide a received signal.
6. The method of Claim 5 wherein said step of calculating a first set of signal correlation energy values comprises the steps of: despreading said received signal in accordance with each PN sequence of said first set of PN sequences to provide a first set of despread signals; and calculating a signal correlation energy value for each of said despread signals.
7. The method of Claim 1 further comprising the step of generating said first set of PN sequences. 8. The method of Claim 7 wherein said the step of generating said first set of PN sequences, comprises the steps of: providing a control signal; and generating a PN sequence of said first set of PN sequences in accordance with said control signal.
9. The method of Claim 8 wherein said control signal is a temporal offset and said step of generating a PN sequence comprises outputting said PN sequence from a shift register in accordance with said temporal offset.
10. The method of Claim 1 wherein said first set of PN sequences comprise quadrature PNj and PNQ sequences.
11. The method of Claim 10 wherein said step of calculating said signal correlation energy value for each of said despread signals comprises the steps of: generating said PNj. and PNQ sequences; despreading an I component of a received signal and a Q component of a received signal by said PNi and PNQ sequences to provide corresponding despread I and Q components of said received signal; coherently accumulating said despread I components of said received signal to provide an accumulated I component; coherently accumulating said despread Q components of said received signal to provide an accumulated Q component; squaring each of said accumulated I component and said accumulated
Q component and summing said squares of said accumulated I component and said accumulated Q component; and noncoherently combining said sum of said squares of said accumulated I component and said accumulated Q component.
12. An apparatus for selecting a synchronized demodulation sequence comprising: sequence generator means for receiving a first control signal for providing a plurality of demodulation sequences in response to said first control signal; demodulator means for receiving a received signal and demodulating a received signal in accordance with said plurality of demodulation sequences to provide a plurality of despread signals; correlator means for receiving said plurality of despread signals and calculating signal correlation energy values for said plurality of despread signals; searcher controller means for receiving said signal correlation energy values and for providing said first control signal and for providing a second control signal in accordance with said signal correlation energy values; and wherein said sequence generator means is further for receiving said second control signal and for providing a second plurality of demodulation sequences in response to said second control signal and wherein said second plurality of demodulation sequences are a subset of said first plurality of demodulation sequences.
13. The apparatus of Claim 12 wherein said correlator means comprises accumulator means for receiving said plurality of despread signals and for summing the despread signals over the length of the demodulation sequences.
14. The apparatus of Claim 12 wherein said received signal comprises a first received signal component and a second received signal component and wherein said demodulator means is for receiving said first received signal component and said second received signal component and for demodulating said first received signal component in accordance with a first plurality of demodulation sequences to provide a first plurality of despread signals and for demodulating said second received signal component in accordance with a second plurality of demodulation sequences to provide a second plurality of despread signals and wherein said sequence generator means is for generating said first plurality of demodulation sequences and said second plurality of demodulation sequences.
15. The apparatus of Claim 14 wherein said correlator means comprises: first accumulator means for receiving said first plurality of despread signals and for summing each of said plurality of despread signals over the length of the demodulation sequences to provide a first plurality of despread sum values; second accumulator means for receiving said second plurality of despread signals and for summing each of said plurality of despread signals over the length of the demodulation sequences to provide a second plurality of despread sum values; combiner means for receiving said first plurality of despread sum values and for receiving said second plurality of despread sum values and for combining said first plurality of despread sum values and said second plurality of despread sum values to provide said signal correlation energy values.
16. The apparatus of Claim 15 wherein said combiner means comprises: squaring means for receiving said first plurality of despread sum values and for receiving said second plurality of despread sum values and for squaring each of said first plurality of despread sum values and each of said second plurality of despread sum values and adding each of said first plurality of squared despread sum values to a corresponding one of said second plurality of squared despread sum values to provide a plurality of energy magnitude values; and noncoherent combiner for receiving said plurality of energy magnitude values and computing said signal correlation energy values in accordance with said plurality of energy magnitude values.
17. The apparatus of Claim 16 wherein said searcher controller means is further for providing a combination signal and wherein said noncoherent combiner is responsive to said combination signal.
18. A system for selecting a synchronized demodulation sequence comprising: a sequence generator having an input for receiving a first control signal and having an output; a demodulator having an input coupled to said sequence generator output and having an output; a correlator having an input coupled to said demodulator output and having an output; and searcher controller having an input coupled to said correlator output.
19. The system of Claim 18 wherein said correlator is a coherent accumulator. 20. The system of Claim 18 wherein said sequence generator has a second output and wherein said demodulator has a second input coupled to said sequence generator second output.
21. The system of Claim 18 wherein said demodulator has a second output and wherein said correlator comprises: a first coherent accumulator having an input coupled to said demodulator output and having an output; a second coherent accumulator having an input coupled to said second demodulator output and having an output; a sum of the squares calculator having a first input coupled to said first coherent accumulator output and having a second input coupled to said second coherent accumulator output and having an output; a noncoherent accumulator having an input coupled to said sum of the squares calculator output.
PCT/US1995/008659 1994-07-29 1995-07-10 Method and apparatus for performing code acquisition in a cdma communications system WO1996004716A1 (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
MX9601211A MX9601211A (en) 1994-07-29 1995-07-10 Method and apparatus for performing code acquisition in a cdma communications system.
AU30958/95A AU687228B2 (en) 1994-07-29 1995-07-10 Method and apparatus for performing code acquisition in a CDMA communications system
BR9506273A BR9506273A (en) 1994-07-29 1995-07-10 Method for determining the synchronization of the pn sequence in a spread spectrum communication system by direct sequence and apparatus and system for selecting a synchronized demodulation sequence
JP8506511A JP3040481B2 (en) 1994-07-29 1995-07-10 Method and apparatus for performing search acquisition in a CDMA communication system
DE69533540T DE69533540T2 (en) 1994-07-29 1995-07-10 METHOD AND DEVICE FOR EXECUTING THE CODE DETECTION IN A CDMA TRANSMISSION SYSTEM
EP95926654A EP0721703B1 (en) 1994-07-29 1995-07-10 Method and apparatus for performing code acquisition in a cdma communications system
AT95926654T ATE277458T1 (en) 1994-07-29 1995-07-10 METHOD AND APPARATUS FOR PERFORMING CODE DETECTION IN A CDMA TRANSMISSION SYSTEM
CA002172370A CA2172370C (en) 1994-07-29 1995-07-10 Method and apparatus for performing code acquisition in a cdma communications system
FI961294A FI114593B (en) 1994-07-29 1996-03-20 Developed procedure and apparatus for conducting search identification in a CDMA telecommunication system
HK98116179A HK1015197A1 (en) 1994-07-29 1998-12-28 Method and apparatus for performing code acquisition in a cdma communications system.

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US28330494A 1994-07-29 1994-07-29
US283,304 1994-07-29

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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0952750A2 (en) * 1998-04-24 1999-10-27 Lucent Technologies Inc. Channel search scheme for receivers in CDMA mobile communication systems
EP1028564A1 (en) * 1999-02-11 2000-08-16 Motorola, Inc. Estimation of carrier and sampling frequency offsets in multicarrier receivers
US6154487A (en) * 1997-05-21 2000-11-28 Mitsubishi Denki Kabushiki Kaisha Spread-spectrum signal receiving method and spread-spectrum signal receiving apparatus
WO2001017125A1 (en) * 1999-08-31 2001-03-08 Qualcomm Incorporated Method and apparatus for reducing pilot search times utilizing mobile station location information
WO2001026243A1 (en) * 1999-10-06 2001-04-12 Nec Corporation Cdma receiver, and reception method
WO2001047136A1 (en) * 1999-12-22 2001-06-28 Qualcomm Incorporated Method and apparatus for performing search acquisition in a multi-carrier communication system
WO2001089109A2 (en) * 2000-05-18 2001-11-22 Telefonaktiebolaget Lm Ericsson (Publ) Radio reciever and channel estimator
CN1080962C (en) * 1996-03-22 2002-03-13 松下电器产业株式会社 Synchronizer for receiver of spectrum spreading communication apparatus
EP1220482A1 (en) * 1999-09-24 2002-07-03 NEC Corporation Search method in cdma mobile communication receiving system and receiving device
EP1263149A2 (en) * 2001-05-31 2002-12-04 Fujitsu Limited CDMA receiver
GB2383925A (en) * 2002-01-04 2003-07-09 Ubinetics Ltd Pilot signal detection using varying window sizes
KR100806094B1 (en) * 1999-12-22 2008-02-21 퀄컴 인코포레이티드 Method and apparatus for performing search acquisition in a multi-carrier communication system
EP2229026A1 (en) * 1997-02-18 2010-09-15 Qualcomm Incorporated Method of and apparatus for avoiding lost communication with a mobile station
DE10102709B4 (en) * 2001-01-22 2014-02-06 Rohde & Schwarz Gmbh & Co. Kg Method and apparatus for synchronization to a pilot sequence of a CDMA signal

Families Citing this family (135)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3444001B2 (en) * 1995-02-10 2003-09-08 ソニー株式会社 Sign detection circuit
US5627835A (en) * 1995-04-04 1997-05-06 Oki Telecom Artificial window size interrupt reduction system for CDMA receiver
JPH0983429A (en) * 1995-09-18 1997-03-28 Toshiba Corp Mobile station equipment and spread code synchronization method for cdma cellular radio system
JPH09148980A (en) * 1995-11-22 1997-06-06 Sony Corp Detection of pilot signal, pilot signal detection device and moving station reception device
US5778022A (en) * 1995-12-06 1998-07-07 Rockwell International Corporation Extended time tracking and peak energy in-window demodulation for use in a direct sequence spread spectrum system
US5715240A (en) * 1996-05-03 1998-02-03 Motorola, Inc. Communication device capable of estimating signal quality without synchronization pattern
US5781543A (en) * 1996-08-29 1998-07-14 Qualcomm Incorporated Power-efficient acquisition of a CDMA pilot signal
US5889768A (en) * 1996-08-30 1999-03-30 Motorola, Inc. Method of and apparatus for pilot channel acquisition
US6233247B1 (en) * 1998-03-12 2001-05-15 Nortel Networks Limited Method and system for avoiding communication failure in CDMA systems
JP2856198B2 (en) * 1997-06-11 1999-02-10 日本電気株式会社 Spread spectrum receiver
JP2861985B2 (en) * 1997-06-16 1999-02-24 日本電気株式会社 High-speed cell search method for CDMA
JP3274388B2 (en) * 1997-07-25 2002-04-15 株式会社東芝 RAKE receiver and spread spectrum communication apparatus provided with the RAKE receiver
US5872774A (en) * 1997-09-19 1999-02-16 Qualcomm Incorporated Mobile station assisted timing synchronization in a CDMA communication system
US5960329A (en) * 1997-09-26 1999-09-28 Gte Laboratories Incorporated System and method for determining guard zone and guard bands in a digital cellular dual mode network
US6531982B1 (en) 1997-09-30 2003-03-11 Sirf Technology, Inc. Field unit for use in a GPS system
US6144691A (en) * 1997-09-30 2000-11-07 Nokia Mobile Phones Limited Method and apparatus for synchronizing to a direct sequence spread spectrum signal
DE69841326D1 (en) 1997-10-10 2010-01-07 Qualcomm Inc MULTIPLE PN CODE SPREADING IN A MULTI-USER COMMUNICATION SYSTEM
US6058136A (en) * 1997-12-11 2000-05-02 Gte Laboratories Incorporated System and method for PN offset index planning in a digital CDMA cellular network
US6618432B1 (en) 1997-12-11 2003-09-09 Verizon Laboratories Inc. Systems and methods for minimizing interference and optimizing PN planning in CDMA networks
US6154455A (en) * 1997-12-24 2000-11-28 Nokia Mobile Phones Limited Prioritizing pilot set searching for a CDMA telecommunications system
KR100268135B1 (en) 1998-02-17 2000-10-16 이병기 Apparatus and method for performing fast acquisition of pn sequence by transferring distributed samples
US6327471B1 (en) 1998-02-19 2001-12-04 Conexant Systems, Inc. Method and an apparatus for positioning system assisted cellular radiotelephone handoff and dropoff
US6101173A (en) * 1998-03-16 2000-08-08 Qualcomm Incorporated Adaptive reacquisition time in a slotted paging environment
US6668009B2 (en) 1998-03-23 2003-12-23 Lg Information & Communications, Ltd. Apparatus and method for performing fast acquisition of PN sequences by transferring distributed samples
US6243584B1 (en) 1998-03-30 2001-06-05 Verizon Laboratories Inc. System and method for increasing CDMA capacity by frequency assignment
KR100268677B1 (en) * 1998-04-04 2000-10-16 윤종용 Device and method for acquiring phase of spreading code in cdma communication system
US6348744B1 (en) 1998-04-14 2002-02-19 Conexant Systems, Inc. Integrated power management module
KR100291477B1 (en) * 1998-06-02 2001-07-12 윤종용 A sequential searching method on the variable data rate transmission environment in mobile telecommunication systems
KR100277761B1 (en) * 1998-06-25 2001-01-15 윤종용 Estimation method of the window size of mobile station in a cellular system
US6310856B1 (en) 1998-08-07 2001-10-30 Motorola, Inc. CDMA communications system having a searcher receiver and method therefor
US5991285A (en) * 1998-08-10 1999-11-23 Motorola, Inc. Method and apparatus for communicating signals of various channel types in CDMA communication system
KR100268872B1 (en) 1998-08-28 2000-10-16 김영환 Anti-theft circuit for potable device.
US7545854B1 (en) 1998-09-01 2009-06-09 Sirf Technology, Inc. Doppler corrected spread spectrum matched filter
US7711038B1 (en) 1998-09-01 2010-05-04 Sirf Technology, Inc. System and method for despreading in a spread spectrum matched filter
US6275483B1 (en) * 1998-09-03 2001-08-14 Texas Instruments Incorporated Fast and accurate identification of spread spectrum signals
US6765953B1 (en) * 1998-09-09 2004-07-20 Qualcomm Incorporated User terminal parallel searcher
US6201827B1 (en) 1998-09-09 2001-03-13 Qualcomm Incorporated System and method for probability based lock detection
US6693953B2 (en) 1998-09-30 2004-02-17 Skyworks Solutions, Inc. Adaptive wireless communication receiver
CA2282800C (en) * 1998-11-09 2007-07-31 Lucent Technologies Inc. A coherent combining/noncoherent detection (ccnd) method and apparatus for detecting a pilot signal in a wireless communication system
US6421371B1 (en) 1998-11-17 2002-07-16 Ericsson Inc. Modulation sequence synchronization methods and apparatus employing partial sequence correlation
US6229841B1 (en) 1998-12-11 2001-05-08 Qualcomm Incorporated Method and apparatus for energy estimation in a wireless receiver capable of receiving multiple instances of a common signal
US6130923A (en) * 1998-12-11 2000-10-10 Qualcomm Incorporated Lock detection for multipath wireless receiver
US6448925B1 (en) 1999-02-04 2002-09-10 Conexant Systems, Inc. Jamming detection and blanking for GPS receivers
US6606349B1 (en) 1999-02-04 2003-08-12 Sirf Technology, Inc. Spread spectrum receiver performance improvement
US6577271B1 (en) 1999-03-30 2003-06-10 Sirf Technology, Inc Signal detector employing coherent integration
US6304216B1 (en) * 1999-03-30 2001-10-16 Conexant Systems, Inc. Signal detector employing correlation analysis of non-uniform and disjoint sample segments
US6363108B1 (en) * 1999-03-31 2002-03-26 Qualcomm Inc. Programmable matched filter searcher
US6925067B2 (en) * 1999-04-23 2005-08-02 Qualcomm, Incorporated Configuration of overhead channels in a mixed bandwidth system
US6704348B2 (en) * 2001-05-18 2004-03-09 Global Locate, Inc. Method and apparatus for computing signal correlation at multiple resolutions
JP3322240B2 (en) 1999-05-10 2002-09-09 日本電気株式会社 CDMA receiver
US6850507B1 (en) * 1999-05-12 2005-02-01 Samsung Electronics Co., Ltd. Apparatus and method for acquiring PN sequence in multicarrier CDMA mobile communication system
US7031271B1 (en) * 1999-05-19 2006-04-18 Motorola, Inc. Method of and apparatus for activating a spread-spectrum radiotelephone
US7085246B1 (en) * 1999-05-19 2006-08-01 Motorola, Inc. Method and apparatus for acquisition of a spread-spectrum signal
US6351486B1 (en) * 1999-05-25 2002-02-26 Conexant Systems, Inc. Accelerated selection of a base station in a wireless communication system
KR100513710B1 (en) 1999-05-25 2005-09-07 삼성전자주식회사 Method and apparatus for performing code acquisition in CDMA communications system
US6430170B1 (en) 1999-05-27 2002-08-06 Qualcomm Inc. Method and apparatus for generating random numbers from a communication signal
US6519237B1 (en) * 1999-05-28 2003-02-11 Koninklijke Philips Electronics N.V. Apparatus and method for parallel searching and correlating for CDMA system
US6640236B1 (en) 1999-08-31 2003-10-28 Qualcomm Incorporated Method and apparatus for generating multiple bits of a pseudonoise sequence with each clock pulse by computing the bits in parallel
US6778507B1 (en) 1999-09-01 2004-08-17 Qualcomm Incorporated Method and apparatus for beamforming in a wireless communication system
US6829290B1 (en) * 1999-09-28 2004-12-07 Texas Instruments Incorporated Wireless communications system with combining of multiple paths selected from correlation to the primary synchronization channel
US6831956B1 (en) 1999-09-28 2004-12-14 Texas Instruments Incorporated Wireless communications system with combining of multiple paths selected from sub-windows in response to the primary synchronization channel
US6377615B1 (en) * 1999-09-30 2002-04-23 Ericsson Inc. Apparatus and methods for receiving information using variable length accumulation searchers
US6683924B1 (en) * 1999-10-19 2004-01-27 Ericsson Inc. Apparatus and methods for selective correlation timing in rake receivers
KR100317339B1 (en) * 1999-11-12 2001-12-24 이병기 Parallel Distributed Sample Acquisition System and Method for spread spectrum signal acquisition using the same
US6822999B1 (en) * 1999-11-13 2004-11-23 Lg Electronics Inc. High-speed cell searching apparatus and method for communication system
US6490313B1 (en) 1999-12-11 2002-12-03 Verizon Laboratories Inc. System and method for PN offset index planning in a digital CDMA cellular network
KR100390404B1 (en) * 1999-12-18 2003-07-07 김병훈 high speed cell searching method using DDSA, and apparatus for the same
DE19961594B4 (en) * 1999-12-21 2013-08-14 Ipcom Gmbh & Co. Kg Method for the transmission of data signals between a transmitting station and several receiving stations, transmitting station and receiving station
JP2001244849A (en) * 2000-02-29 2001-09-07 Matsushita Electric Ind Co Ltd Communicaiton terminal and cell search method
US6397068B1 (en) 2000-03-17 2002-05-28 Verizon Laboratories Inc. System and method for optimally selecting guard bands in a dual mode network
US6556621B1 (en) 2000-03-29 2003-04-29 Time Domain Corporation System for fast lock and acquisition of ultra-wideband signals
US6775252B1 (en) * 2000-03-31 2004-08-10 Qualcomm, Inc. Dynamic adjustment of search window size in response to signal strength
US7224719B1 (en) 2000-03-31 2007-05-29 Qualcomm, Incorporated Fast acquisition of a pilot signal in a wireless communication device
US6931055B1 (en) 2000-04-18 2005-08-16 Sirf Technology, Inc. Signal detector employing a doppler phase correction system
US6714158B1 (en) 2000-04-18 2004-03-30 Sirf Technology, Inc. Method and system for data detection in a global positioning system satellite receiver
US6952440B1 (en) 2000-04-18 2005-10-04 Sirf Technology, Inc. Signal detector employing a Doppler phase correction system
US6788655B1 (en) 2000-04-18 2004-09-07 Sirf Technology, Inc. Personal communications device with ratio counter
US7885314B1 (en) 2000-05-02 2011-02-08 Kenneth Scott Walley Cancellation system and method for a wireless positioning system
US6778136B2 (en) 2001-12-13 2004-08-17 Sirf Technology, Inc. Fast acquisition of GPS signal
GB2368238B (en) * 2000-10-17 2004-04-14 Ubinetics Ltd A method of searching a code space
US20020060998A1 (en) * 2000-11-22 2002-05-23 Hunzinger Jason F. CDMA search processing load reduction
JP3695316B2 (en) * 2000-11-24 2005-09-14 株式会社日本自動車部品総合研究所 Spread spectrum receiver correlation detector
JP2002164811A (en) * 2000-11-24 2002-06-07 Toshiba Corp Time identification method, time identification unit and time identification system
US6985516B1 (en) 2000-11-27 2006-01-10 Qualcomm Incorporated Method and apparatus for processing a received signal in a communications system
WO2002043264A2 (en) * 2000-11-27 2002-05-30 Telefonaktiebolaget Lm Ericsson (Publ) Code synchronization in a mobile communication device
US6954644B2 (en) 2000-12-04 2005-10-11 Telefonaktiebolaget Lm Ericsson (Publ) Using geographical coordinates to determine mobile station time position for synchronization during diversity handover
US6907245B2 (en) 2000-12-04 2005-06-14 Telefonaktiebolaget Lm Ericsson (Publ) Dynamic offset threshold for diversity handover in telecommunications system
US6980803B2 (en) * 2000-12-04 2005-12-27 Telefonaktiebolaget Lm Ericsson (Publ) Using statistically ascertained position for starting synchronization searcher during diversity handover
KR100488078B1 (en) * 2000-12-21 2005-05-09 엘지전자 주식회사 Pilot Signal Detector of Mobile Communication System and Method thereof
US20020136234A1 (en) * 2001-02-14 2002-09-26 Hakan Eriksson Tuning the fingers of rake receiver
US6700922B2 (en) * 2001-04-09 2004-03-02 Raghu Challa System and method for acquiring a received signal in a spread spectrum device
US7190712B2 (en) * 2001-05-18 2007-03-13 Global Locate, Inc Method and apparatus for performing signal correlation
US7995682B2 (en) * 2001-05-18 2011-08-09 Broadcom Corporation Method and apparatus for performing signal processing using historical correlation data
US7006556B2 (en) 2001-05-18 2006-02-28 Global Locate, Inc. Method and apparatus for performing signal correlation at multiple resolutions to mitigate multipath interference
US6891880B2 (en) * 2001-05-18 2005-05-10 Global Locate, Inc. Method and apparatus for performing signal correlation
US7769076B2 (en) 2001-05-18 2010-08-03 Broadcom Corporation Method and apparatus for performing frequency synchronization
US7567636B2 (en) * 2001-05-18 2009-07-28 Global Locate, Inc. Method and apparatus for performing signal correlation using historical correlation data
US8611311B2 (en) 2001-06-06 2013-12-17 Qualcomm Incorporated Method and apparatus for canceling pilot interference in a wireless communication system
US20050013350A1 (en) * 2001-06-06 2005-01-20 Coralli Alessandro Vanelli Method and apparatus for canceling pilot interference in a wireless communication system
US7190749B2 (en) * 2001-06-06 2007-03-13 Qualcomm Incorporated Method and apparatus for canceling pilot interference in a wireless communication system
US6959053B2 (en) * 2001-07-13 2005-10-25 Koninklijke Philips Electronics N.V. Method and apparatus for searching for a pre-defined code in a bit stream
US6795489B2 (en) 2001-08-09 2004-09-21 Qualcomm Inc. Acquisition of a gated pilot
JP3719175B2 (en) 2001-08-22 2005-11-24 日本電気株式会社 Synchronous tracking circuit
US6738438B2 (en) 2001-10-29 2004-05-18 Qualcomm Incorporated Parameter estimator with dynamically variable search window size and/or placement
US7729412B2 (en) * 2001-10-29 2010-06-01 Qualcomm Incorporated Parameter estimator with dynamically variable integration time
US7308022B2 (en) * 2001-11-01 2007-12-11 Rick Roland R Parameter estimator configured to distinguish between peaks and sidelobes of correlation function
US7558534B2 (en) 2001-11-02 2009-07-07 Qualcomm Incorporated Reliability metrics for parameter estimates which account for cumulative error
US7298776B2 (en) * 2001-12-14 2007-11-20 Qualcomm Incorporated Acquisition of a gated pilot signal with coherent and noncoherent integration
KR100426621B1 (en) * 2001-12-20 2004-04-13 한국전자통신연구원 Small-window-sized preamble search apparatus and method to search preamble signal of terminal
KR100775346B1 (en) * 2001-12-26 2007-11-12 엘지전자 주식회사 Apparatus for searching neighboring cell
CN1292261C (en) * 2002-01-24 2006-12-27 华为技术有限公司 Localization measurement method of mobile station
US6724343B2 (en) * 2002-04-30 2004-04-20 The Johns Hopkins University Weak signal and anti-jamming Global Positioning System receiver and method using full correlation grid
US7233624B2 (en) * 2002-06-11 2007-06-19 Interdigital Technology Corporation Method and system for all digital gain control
US7295857B2 (en) * 2002-10-30 2007-11-13 Qualcomm Incorporated Method and apparatus for performing acquisition in power save mode for wireless communication systems
EP1422831A1 (en) * 2002-11-22 2004-05-26 Siemens Aktiengesellschaft Method for the processing in the receiver of a CDMA signal in a radio communication system
US7995926B2 (en) 2003-02-21 2011-08-09 Northrop Grumman Systems Corporation Scanned acquisition using pre-track data
WO2004107599A1 (en) * 2003-05-27 2004-12-09 Telefonaktiebolaget L M Ericsson (Publ) Positioning a multipath search window
ATE317606T1 (en) * 2003-05-27 2006-02-15 POSITIONING A RESEARCH SLIDING WINDOW FOR MULTI-WAY SIGNAL RECEIPT
US7330452B2 (en) * 2003-06-13 2008-02-12 Qualcomm Incorporated Inter-frequency neighbor list searching
US7412012B2 (en) * 2003-07-08 2008-08-12 Nokia Corporation Pattern sequence synchronization
US20050085230A1 (en) * 2003-10-16 2005-04-21 Motorola, Inc. Circuit and method for producing a pilot strength measurement message
US20050209762A1 (en) * 2004-03-18 2005-09-22 Ford Global Technologies, Llc Method and apparatus for controlling a vehicle using an object detection system and brake-steer
US7907671B2 (en) * 2004-12-03 2011-03-15 Motorola Mobility, Inc. Method and system for scaling a multi-channel signal
US8406695B2 (en) 2004-12-23 2013-03-26 Qualcomm Incorporated Joint interference cancellation of pilot, overhead and traffic channels
US8422955B2 (en) 2004-12-23 2013-04-16 Qualcomm Incorporated Channel estimation for interference cancellation
US8442441B2 (en) * 2004-12-23 2013-05-14 Qualcomm Incorporated Traffic interference cancellation
US8099123B2 (en) 2004-12-23 2012-01-17 Qualcomm Incorporated Adaptation of transmit subchannel gains in a system with interference cancellation
KR20060085132A (en) * 2005-01-22 2006-07-26 삼성전자주식회사 Apparatus and method for obtaining pilot synchronous in code division multiplex system
US8472877B2 (en) * 2005-10-24 2013-06-25 Qualcomm Incorporated Iterative interference cancellation system and method
US8385388B2 (en) * 2005-12-06 2013-02-26 Qualcomm Incorporated Method and system for signal reconstruction from spatially and temporally correlated received samples
US8920343B2 (en) 2006-03-23 2014-12-30 Michael Edward Sabatino Apparatus for acquiring and processing of physiological auditory signals
US8228971B2 (en) 2008-07-29 2012-07-24 Agere Systems Inc. Technique for searching for a preamble signal in a spread spectrum signal using a fast Hadamard transform
FR2943192B1 (en) * 2009-03-13 2011-06-03 St Wireless Sa METHOD FOR ASSIGNING A FINGER FOR A RAKE TYPE RECEIVER AND DEVICE FOR CARRYING OUT THE METHOD
US8300675B2 (en) * 2009-05-13 2012-10-30 Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of Industry, Through The Communications Research Centre Canada Spreading code acquisition for direct sequence spread spectrum signals
KR101106164B1 (en) 2009-09-01 2012-01-20 세종대학교산학협력단 System and method for acquiring initial synchronization using multiple threshold level

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992000639A1 (en) * 1990-06-25 1992-01-09 Qualcomm Incorporated System and method for generating signal waveforms in a cdma cellular telephone system
US5177765A (en) * 1991-06-03 1993-01-05 Spectralink Corporation Direct-sequence spread-spectrum digital signal acquisition and tracking system and method therefor

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3715508A (en) * 1967-09-15 1973-02-06 Ibm Switching circuits employing orthogonal and quasi-orthogonal pseudo-random code sequences
US4052565A (en) * 1975-05-28 1977-10-04 Martin Marietta Corporation Walsh function signal scrambler
US4301530A (en) * 1978-12-18 1981-11-17 The United States Of America As Represented By The Secretary Of The Army Orthogonal spread spectrum time division multiple accessing mobile subscriber access system
US4730340A (en) * 1980-10-31 1988-03-08 Harris Corp. Programmable time invariant coherent spread symbol correlator
US4472815A (en) * 1982-09-27 1984-09-18 The United States Of America As Represented By The Secretary Of The Army Pulse interference cancelling system for spread spectrum signals
US4460992A (en) * 1982-11-04 1984-07-17 The United States Of America As Represented By The Secretary Of The Army Orthogonal CDMA system utilizing direct sequence pseudo noise codes
JPS6090222A (en) * 1983-10-21 1985-05-21 Hitachi Cable Ltd Method for treating high polymer with radiation
US4635221A (en) * 1985-01-18 1987-01-06 Allied Corporation Frequency multiplexed convolver communication system
US4901307A (en) * 1986-10-17 1990-02-13 Qualcomm, Inc. Spread spectrum multiple access communication system using satellite or terrestrial repeaters
NL8700930A (en) * 1987-04-17 1988-11-16 Hollandse Signaalapparaten Bv SYSTEM OF ORTHOGONALLY OPERATING CODE GENERATORS, RADIOS EQUIPPED WITH A CODE GENERATOR AND CODE GENERATORS OF SUCH A SYSTEM.
FR2629931B1 (en) * 1988-04-08 1991-01-25 Lmt Radio Professionelle ASYNCHRONOUS DIGITAL CORRELATOR AND DEMODULATORS COMPRISING SUCH A CORRELATOR
JPH06103873B2 (en) * 1988-09-01 1994-12-14 三菱電機株式会社 Orthogonal sequence generation method
US5101501A (en) * 1989-11-07 1992-03-31 Qualcomm Incorporated Method and system for providing a soft handoff in communications in a cdma cellular telephone system
US5363401A (en) * 1993-02-25 1994-11-08 Harris Corporation Mechanism for extracting hybrid (fh/ds) spread spectrum signals within multi-signal type environment

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992000639A1 (en) * 1990-06-25 1992-01-09 Qualcomm Incorporated System and method for generating signal waveforms in a cdma cellular telephone system
US5177765A (en) * 1991-06-03 1993-01-05 Spectralink Corporation Direct-sequence spread-spectrum digital signal acquisition and tracking system and method therefor

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1080962C (en) * 1996-03-22 2002-03-13 松下电器产业株式会社 Synchronizer for receiver of spectrum spreading communication apparatus
EP2229026A1 (en) * 1997-02-18 2010-09-15 Qualcomm Incorporated Method of and apparatus for avoiding lost communication with a mobile station
US6154487A (en) * 1997-05-21 2000-11-28 Mitsubishi Denki Kabushiki Kaisha Spread-spectrum signal receiving method and spread-spectrum signal receiving apparatus
CN1104116C (en) * 1997-05-21 2003-03-26 三菱电机株式会社 Spread-spectrum signal receiving method and spread-spectrum signal receiving apparatus
US6526029B1 (en) 1998-04-24 2003-02-25 Lucent Technologies Inc. Search scheme for receivers in mobile communication systems
EP0952750A2 (en) * 1998-04-24 1999-10-27 Lucent Technologies Inc. Channel search scheme for receivers in CDMA mobile communication systems
EP0952750A3 (en) * 1998-04-24 2001-10-04 Lucent Technologies Inc. Channel search scheme for receivers in CDMA mobile communication systems
EP1028564A1 (en) * 1999-02-11 2000-08-16 Motorola, Inc. Estimation of carrier and sampling frequency offsets in multicarrier receivers
US6198782B1 (en) 1999-02-11 2001-03-06 Motorola, Inc. Estimation of frequency offsets in OFDM communication systems
US7236796B2 (en) 1999-08-31 2007-06-26 Qualcomm Incorporated Method and apparatus for reducing pilot search times utilizing mobile station location information
WO2001017125A1 (en) * 1999-08-31 2001-03-08 Qualcomm Incorporated Method and apparatus for reducing pilot search times utilizing mobile station location information
AU770480B2 (en) * 1999-08-31 2004-02-19 Qualcomm Incorporated Method and apparatus for reducing pilot search times utilizing mobile station location information
US6542743B1 (en) 1999-08-31 2003-04-01 Qualcomm, Incorporated Method and apparatus for reducing pilot search times utilizing mobile station location information
EP1501205A1 (en) * 1999-08-31 2005-01-26 QUALCOMM Incorporated Method and apparatus for reducing pilot search times utilizing mobile station location information
EP1220482A1 (en) * 1999-09-24 2002-07-03 NEC Corporation Search method in cdma mobile communication receiving system and receiving device
US7079569B1 (en) 1999-09-24 2006-07-18 Nec Corporation Search method in CDMA mobile communication receiving system and receiving device
EP1220482A4 (en) * 1999-09-24 2003-01-29 Nec Corp Search method in cdma mobile communication receiving system and receiving device
WO2001026243A1 (en) * 1999-10-06 2001-04-12 Nec Corporation Cdma receiver, and reception method
US6466606B1 (en) 1999-12-22 2002-10-15 Qualcomm, Incorporated Method and apparatus for performing search acquisition in a multi-carrier communication system
KR100806094B1 (en) * 1999-12-22 2008-02-21 퀄컴 인코포레이티드 Method and apparatus for performing search acquisition in a multi-carrier communication system
CN100388638C (en) * 1999-12-22 2008-05-14 高通股份有限公司 Method and apparatus for performing search acquisition in multi-carrier communication system
WO2001047136A1 (en) * 1999-12-22 2001-06-28 Qualcomm Incorporated Method and apparatus for performing search acquisition in a multi-carrier communication system
WO2001089109A3 (en) * 2000-05-18 2003-12-31 Ericsson Telefon Ab L M Radio reciever and channel estimator
US7054353B2 (en) 2000-05-18 2006-05-30 Telefonaktiebolaget Lm Ericsson (Publ) Radio receiver and channel estimator
WO2001089109A2 (en) * 2000-05-18 2001-11-22 Telefonaktiebolaget Lm Ericsson (Publ) Radio reciever and channel estimator
DE10102709B4 (en) * 2001-01-22 2014-02-06 Rohde & Schwarz Gmbh & Co. Kg Method and apparatus for synchronization to a pilot sequence of a CDMA signal
EP1263149A3 (en) * 2001-05-31 2005-01-26 Fujitsu Limited CDMA receiver
EP1263149A2 (en) * 2001-05-31 2002-12-04 Fujitsu Limited CDMA receiver
GB2383925A (en) * 2002-01-04 2003-07-09 Ubinetics Ltd Pilot signal detection using varying window sizes

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