WO1995012924A1 - Spread spectrum spectral density techniques - Google Patents

Spread spectrum spectral density techniques Download PDF

Info

Publication number
WO1995012924A1
WO1995012924A1 PCT/US1994/012465 US9412465W WO9512924A1 WO 1995012924 A1 WO1995012924 A1 WO 1995012924A1 US 9412465 W US9412465 W US 9412465W WO 9512924 A1 WO9512924 A1 WO 9512924A1
Authority
WO
WIPO (PCT)
Prior art keywords
pseudo
chip sequence
random
sequence
data bits
Prior art date
Application number
PCT/US1994/012465
Other languages
French (fr)
Inventor
Robert C. Dixon
Scott R. Bullock
Original Assignee
Omnipoint Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Omnipoint Corporation filed Critical Omnipoint Corporation
Priority to JP7513326A priority Critical patent/JPH09504670A/en
Priority to KR1019960702228A priority patent/KR960706233A/en
Priority to EP95901086A priority patent/EP0727111A4/en
Publication of WO1995012924A1 publication Critical patent/WO1995012924A1/en

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J13/00Code division multiplex systems
    • H04J13/10Code generation
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J13/00Code division multiplex systems
    • H04J13/10Code generation
    • H04J13/102Combining codes
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B1/00Details 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
    • H04B1/69Spread spectrum techniques
    • H04B1/707Spread spectrum techniques using direct sequence modulation

Definitions

  • This invention relates to spectral density techniques for use with spread-spectrum modulation.
  • a data stream may be modulated with a pseudo-random code, so that the energy of the modulated signal is spread over a bandwidth which is larger than the bandwidth of the data stream.
  • Present regulations for communication in a band of electromagnetic spectrum in which spread-spectrum communication is allowed, generally require all parts of the modulated signal to be no more than +8 db power over the signal average, measured over a 3 KHZ resolution bandwidth.
  • the modulated signal may at times not be sufficiently random to meet the regulatory requirement. Accordingly, it would be advantageous to generate a spread-spectrum signal using relatively short pseudo-random codes which meets the regulatory require ⁇ ment.
  • the invention provides a spread-spectrum communication system in which the energy output is more smoothly dis- tributed than the length of the pseudo-random code would otherwise indicate.
  • the invention provides a spread-spectrum communication system in which the code sequence is pseudo-randomly inverted on data-bit bound ⁇ aries, so that the code sequence appears longer, for energy spreading, than it otherwise would appear.
  • Figure 1 shows a block diagram of a spread-spectrum communication transmitter and receiver.
  • Figure 2 shows a block diagram for a pseudo-random code generator for use in a spread-spectrum communication system.
  • FIG. 1 shows a block diagram of a spread-spectrum communication transmitter and receiver.
  • a spread-spectrum transmitter 101 may comprise an input port 102 for input data 103, a chip sequence trans ⁇ mitter generator 104, a modulator 105, and a transmitting antenna 106 for transmitting a spread-spectrum signal 107.
  • a spread-spectrum receiver 108 may comprise a receiver antenna 109, a chip sequence receiver generator 110, a demodulator 111, and an output port 112 for output data 113.
  • a single chip sequence 114 is identically generated by both the transmitter generator 104 and the receiver generator 110, and appears essentially random to others not knowing the spreading code upon which it is based.
  • Figure 2 shows a block diagram for a pseudo-random code generator for use in a spread-spectrum communication system.
  • the transmitter generator 104 and the receiver genera ⁇ tor 110 may comprise a code generator 201, having an output 202 for the chip sequence 114.
  • the chip sequence 114 may comprise a 63-chip maximal-length pseudo-random chip sequence, which is pseudo-randomly inverted by XOR-ing with a second chip sequence at each data bit boundary.
  • the code generator 201 comprises a first generator 203 which generates a first code 204.
  • the first code 204 may comprise a 63-chip linear maximal-length code.
  • An output from the first generator 203 is coupled to a first input of an XOR gate 205.
  • a second generator 206 is clocked at the same rate as the data stream, and generates a second code 207, which is coupled to a second input of the XOR gate 205.
  • the output of the XOR gate 205 is coupled to the output 202 for the code generator 201.
  • the code generator 201 thus generates a complete sequence of the first code 204 for each data bit, but pseudo-randomly inverts the first code 204 by XOR-ing it with the second code 207 at each data bit boundary (i.e., each full data bit is modulated either with the full length of the first code 204 or with the full length of the inverse of the first code 204) .
  • the effect of pseudo-randomly inverting the first code 204 at each data bit boundary is to more smoothly distribute the energy of the modulated signal over the bandwidth it occupies.
  • the first code 204 is 2" - 1 chips long, e.g., 63 chips long
  • the second code 207 is 2 P - 1 chips long, e.g., 63 chips long
  • the modulated signal has about 4 to 7 db maximum power over the signal average, measured in a 3 KHz resolution bandwidth.
  • data information which is transmitted from transmitter to receiver
  • data information which is transmitted from transmitter to receiver
  • data could comprise both data and error-correcting codes, control information, or other signals, and that this would be within the scope and spirit of the invention.

Abstract

A spread-spectrum communication system in which the energy output is more smoothly distributed than the length of the pseudo-random code would otherwise indicate. A spread-spectrum communication system in which the code sequence is pseudo-randomly inverted (205) on data-bit boundaries, so that the code sequence (204) appears longer, for energy spreading, that it otherwise would appear.

Description

DESCRIPTION
Spread Spectrum Spectral Density Techniques
Background of the Invention 1. Field of the Invention
This invention relates to spectral density techniques for use with spread-spectrum modulation.
2. Description of Related Art
In direc -sequence spread-spectrum communication, a data stream may be modulated with a pseudo-random code, so that the energy of the modulated signal is spread over a bandwidth which is larger than the bandwidth of the data stream. Present regulations, for communication in a band of electromagnetic spectrum in which spread-spectrum communication is allowed, generally require all parts of the modulated signal to be no more than +8 db power over the signal average, measured over a 3 KHZ resolution bandwidth. In a spread-spectrum system which uses rela¬ tively short pseudo-random codes, the modulated signal may at times not be sufficiently random to meet the regulatory requirement. Accordingly, it would be advantageous to generate a spread-spectrum signal using relatively short pseudo-random codes which meets the regulatory require¬ ment.
Summary of the Invention
The invention provides a spread-spectrum communication system in which the energy output is more smoothly dis- tributed than the length of the pseudo-random code would otherwise indicate. In particular, the invention provides a spread-spectrum communication system in which the code sequence is pseudo-randomly inverted on data-bit bound¬ aries, so that the code sequence appears longer, for energy spreading, than it otherwise would appear. Brief Description of the Drawings
Figure 1 shows a block diagram of a spread-spectrum communication transmitter and receiver.
Figure 2 shows a block diagram for a pseudo-random code generator for use in a spread-spectrum communication system.
Description of the Preferred Embodiment
Figure 1 shows a block diagram of a spread-spectrum communication transmitter and receiver. A spread-spectrum transmitter 101 may comprise an input port 102 for input data 103, a chip sequence trans¬ mitter generator 104, a modulator 105, and a transmitting antenna 106 for transmitting a spread-spectrum signal 107. A spread-spectrum receiver 108 may comprise a receiver antenna 109, a chip sequence receiver generator 110, a demodulator 111, and an output port 112 for output data 113. In a preferred embodiment, a single chip sequence 114 is identically generated by both the transmitter generator 104 and the receiver generator 110, and appears essentially random to others not knowing the spreading code upon which it is based. An extensive discussion of spread-spectrum communication, spreading codes, and chip sequences, may be found in R. Dixon, SPREAD SPECTRUM SYSTEMS (1984) . Figure 2 shows a block diagram for a pseudo-random code generator for use in a spread-spectrum communication system.
The transmitter generator 104 and the receiver genera¬ tor 110 may comprise a code generator 201, having an output 202 for the chip sequence 114. In a preferred embodiment, the chip sequence 114 may comprise a 63-chip maximal-length pseudo-random chip sequence, which is pseudo-randomly inverted by XOR-ing with a second chip sequence at each data bit boundary. The code generator 201 comprises a first generator 203 which generates a first code 204. In a preferred embodi- ment, the first code 204 may comprise a 63-chip linear maximal-length code. An output from the first generator 203 is coupled to a first input of an XOR gate 205. A second generator 206 is clocked at the same rate as the data stream, and generates a second code 207, which is coupled to a second input of the XOR gate 205. The output of the XOR gate 205 is coupled to the output 202 for the code generator 201.
The code generator 201 thus generates a complete sequence of the first code 204 for each data bit, but pseudo-randomly inverts the first code 204 by XOR-ing it with the second code 207 at each data bit boundary (i.e., each full data bit is modulated either with the full length of the first code 204 or with the full length of the inverse of the first code 204) .
It will be clear to those of ordinary skill in the art, after perusal of this application, that the effect of pseudo-randomly inverting the first code 204 at each data bit boundary is to more smoothly distribute the energy of the modulated signal over the bandwidth it occupies. In a preferred embodiment, the first code 204 is 2" - 1 chips long, e.g., 63 chips long, the second code 207 is 2P - 1 chips long, e.g., 63 chips long, and the modulated signal has about 4 to 7 db maximum power over the signal average, measured in a 3 KHz resolution bandwidth.
Alternative Embodiments
While preferred embodiments are disclosed herein, many variations are possible which remain within the concept and scope of the invention, and these variations would become clear to one of ordinary skill in the art after perusal of the specification, drawings and claims herein.
For example, information which is transmitted from transmitter to receiver is referred to herein as "data", but it would be clear to those of ordinary skill in the art that these data could comprise both data and error- correcting codes, control information, or other signals, and that this would be within the scope and spirit of the invention.

Claims

Claims
1. A method, comprising the steps of receiving a plurality of data bits; generating a pseudo-random chip sequence and an inverse of said pseudo-random chip sequence; pseudo-randomly selecting one or the other of said pseudo-random chip sequence or its inverse; generating a new chip sequence in response to said selection; and modulating each one of said plurality of data bits with said new chip sequence.
2. A method as in claim 1, wherein said step of pseudo-randomly selecting comprises the steps of generating a second pseudo-random chip sequence, said second pseudo-random chip sequence comprising one chip for each data bit; and generating said new chip sequence in response to a boolean operation performed on said original pseudo¬ random chip sequence and said second pseudo-random chip sequence.
3. A method, comprising the steps of receiving a plurality of data bits; receiving a pseudo-random chip sequence; and generating a spread-spectrum signal in response to said plurality of data bits and said pseudo-random chip sequence, said spread-spectrum signal having a smoother spectral energy density than that of a spread-spectrum signal generated by direct-sequence modulation of said plurality of data bits with said pseudo-random chip sequence.
4. A method as in claim 3, wherein said pseudo¬ random chip sequence is a 63-chip maximal length code.
5. A method, comprising the steps of receiving a plurality of data bits; receiving a pseudo-random chip sequence; and generating a spread-spectrum signal in response to said plurality of data bits and a transformation of said pseudo-random chip sequence, said spread-spectrum signal having a smoother spectral energy density than that of a spread-spectrum signal generated by direct-sequence modulation of said plurality of data bits with said pseudo-random chip sequence.
6. A method as in claim 5, wherein said pseudo¬ random chip sequence is a 63-chip maximal length code.
7. A method as in claim 5, wherein said transforma¬ tion of said pseudo-random chip sequence is an inverse of said pseudo-random chip sequence.
8. A method, comprising the steps of receiving a plurality of data bits; generating a first pseudo-random chip sequence at a rate of more than one chip per bit; generating a second pseudo-random chip sequence at a rate of no more than one chip per bit; generating a signal in response to said first and second pseudo-random chip sequences; and spread-spectrum modulating said plurality of data bits with said signal.
9. A method as in claim 8, wherein said step of generating a signal comprises XOR-ing said first and second pseudo-random chip sequences.
10. A method as in claim 8, wherein said first pseudo-random chip sequence is a 63-bit maximal length code.
11. A method as in claim 8, wherein said second pseudo-random chip sequence has a rate of exactly one chip per bit.
12. A code generator for use in a spread spectrum communication system comprising: a first pseudo-noise generator having as an output a first chip sequence, a second pseudo-noise generator having as an output a second chip sequence, an XOR gate, said XOR gate having as inputs said first chip sequence and said second chip sequence, and having as an output either said first chip sequence or an inverse of said first chip sequence in response to said second chip sequence.
13. The code generator of claim 12 further comprising a modulator comprising a first and second input, said output of said XOR gate coupled to said first input, and a data signal coupled to said second input.
14. The code generator of claim 13 wherein said data signal comprises a series of data bits clocked at a predefined rate, and said second chip sequence comprises a series of chips, wherein said second chip sequence is clocked at said predefined rate.
15. The code generator of claim 13 wherein a signal output from said modulator is coupled to a transmitter, and said transmitter transmits said modulator signal over a communication channel.
16. A method of generating a spread spectrum signal comprising the steps of receiving a plurality of data bits; generating a first pseudo-random chip sequence, generating at selected intervals either a second pseudo-random chip sequence or an inverse of said second pseudo-random chip sequence in response to said first pseudo-random chip sequence, and forming a modulation signal thereby; modulating each one of said plurality of data bits with said modulation signal.
17. A method as in claim 16, wherein said selected intervals correspond to boundaries of said data bits.
18. A spread spectrum code generator comprising: a first pseudo-noise generator capable of outputting a first chip sequence, a second pseudo-noise generator capable of outputting a second chip sequence, means for selecting either said first chip sequence or an inverse of said first chip sequence in response to said second chip sequence, and generating an output signal thereby.
19. A spread spectrum code generator as in claim 18, wherein said means for selecting comprises and XOR gate having as inputs said first chip sequence and said second chip sequence.
20. A spread spectrum code generator as in claim 18 wherein said output signal is modulated with a data signal comprising data bits clocked at a predefined rate, and said second chip sequence has a chip rate equal to said predefined rate.
PCT/US1994/012465 1993-11-01 1994-10-31 Spread spectrum spectral density techniques WO1995012924A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP7513326A JPH09504670A (en) 1993-11-01 1994-10-31 Spread spectrum spectral density technology
KR1019960702228A KR960706233A (en) 1993-11-01 1994-10-31 Spread Spectrum Spectral Density Techniques
EP95901086A EP0727111A4 (en) 1993-11-01 1994-10-31 Spread spectrum spectral density techniques

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US08/146,499 1993-11-01
US08/146,499 US5436941A (en) 1993-11-01 1993-11-01 Spread spectrum spectral density techniques

Publications (1)

Publication Number Publication Date
WO1995012924A1 true WO1995012924A1 (en) 1995-05-11

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US (2) US5436941A (en)
EP (1) EP0727111A4 (en)
JP (1) JPH09504670A (en)
KR (1) KR960706233A (en)
CA (1) CA2174647A1 (en)
IL (1) IL111470A (en)
WO (1) WO1995012924A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2340700A (en) * 1998-08-13 2000-02-23 Ramar Technology Ltd A technique to extend the jamming margin of a DSSS communication system
EP1029398B1 (en) * 1997-10-10 2009-11-25 QUALCOMM Incorporated Multi-layered pn code spreading in a multi-user communications system

Families Citing this family (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5436941A (en) * 1993-11-01 1995-07-25 Omnipoint Corporation Spread spectrum spectral density techniques
US6356607B1 (en) 1995-06-05 2002-03-12 Omnipoint Corporation Preamble code structure and detection method and apparatus
US5745484A (en) * 1995-06-05 1998-04-28 Omnipoint Corporation Efficient communication system using time division multiplexing and timing adjustment control
JP3707165B2 (en) * 1996-11-01 2005-10-19 ソニー株式会社 Video transmission method, video processing method, video transmission device, and video processing device
US6141373A (en) 1996-11-15 2000-10-31 Omnipoint Corporation Preamble code structure and detection method and apparatus
GB9700854D0 (en) * 1997-01-16 1997-03-05 Scient Generics Ltd Sub-audible acoustic data transmission mechanism
US6408019B1 (en) 1997-12-29 2002-06-18 Georgia Tech Research Corporation System and method for communication using noise
GB9917985D0 (en) 1999-07-30 1999-09-29 Scient Generics Ltd Acoustic communication system
WO2001097395A2 (en) * 2000-06-12 2001-12-20 Time Domain Corporation A method and apparatus for applying codes having predefined properties
JP2004511172A (en) * 2000-09-29 2004-04-08 株式会社東芝 Code detection circuit and code detection method
EP1928109B1 (en) * 2000-11-30 2012-05-23 Intrasonics S.A.R.L. Cellular telephone for collecting audience survey data
AU2211102A (en) * 2000-11-30 2002-06-11 Scient Generics Ltd Acoustic communication system
US7339605B2 (en) * 2004-04-16 2008-03-04 Polycom, Inc. Conference link between a speakerphone and a video conference unit
WO2003061285A2 (en) * 2001-12-24 2003-07-24 Scientific Generics Limited Captioning system
AU2002308114A1 (en) * 2002-03-29 2003-10-13 Innogenetics N.V. Hbv drug resistance drug resistance detection methods
US8199791B2 (en) * 2005-06-08 2012-06-12 Polycom, Inc. Mixed voice and spread spectrum data signaling with enhanced concealment of data
GB2460306B (en) 2008-05-29 2013-02-13 Intrasonics Sarl Data embedding system
KR101007339B1 (en) * 2008-11-06 2011-01-14 주식회사 텔레칩스 Scrambler device by generating array of pseudo random binary number
WO2020152739A1 (en) * 2019-01-21 2020-07-30 三菱電機株式会社 Transmission device and transmission method

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4774715A (en) * 1987-03-11 1988-09-27 Telesystems Slw Inc. Device for demodulating a spread spectrum signal
US5150377A (en) * 1990-11-02 1992-09-22 At&T Bell Laboratories Direct sequence spread spectrum (dsss) communications system with frequency modulation utilized to achieve spectral spreading

Family Cites Families (52)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4247942A (en) * 1961-03-01 1981-01-27 Ford Aerospace & Communications Corp. Jam resistant communication system
US3934203A (en) * 1974-05-24 1976-01-20 The United States Of America As Represented By The Secretary Of The Navy Spread spectrum modem
US4163944A (en) * 1976-12-22 1979-08-07 Ncr Corporation Compensation circuit for an electrical signal mixer
US4131484A (en) * 1978-02-13 1978-12-26 Western Electric Company, Inc. Frequency adjusting a piezoelectric device by lasering
US4425661A (en) * 1981-09-03 1984-01-10 Applied Spectrum Technologies, Inc. Data under voice communications system
US4479226A (en) * 1982-03-29 1984-10-23 At&T Bell Laboratories Frequency-hopped single sideband mobile radio system
CA1191905A (en) * 1982-06-30 1985-08-13 Canadian Patents And Development Limited/Societe Canadienne Des Brevets Et D'exploitation Limitee Spread spectrum modem
US4561089A (en) * 1984-03-23 1985-12-24 Sangamo Weston, Inc. Correlation detectors for use in direct sequence spread spectrum signal receiver
US4567588A (en) * 1984-03-23 1986-01-28 Sangamo Weston, Inc. Synchronization system for use in direct sequence spread spectrum signal receiver
US4601047A (en) * 1984-03-23 1986-07-15 Sangamo Weston, Inc. Code division multiplexer using direct sequence spread spectrum signal processing
DE3511430A1 (en) * 1985-03-29 1986-10-02 Philips Patentverwaltung Gmbh, 2000 Hamburg METHOD FOR SYNCHRONIZING THE RECEIVING DEVICES IN A DIGITAL MULTIPLEX TRANSMISSION SYSTEM
US4630283A (en) * 1985-07-17 1986-12-16 Rca Corporation Fast acquisition burst mode spread spectrum communications system with pilot carrier
AU593564B2 (en) * 1985-07-24 1990-02-15 Nec Corporation Spread spectrum power line communications
US4672658A (en) * 1985-10-16 1987-06-09 At&T Company And At&T Bell Laboratories Spread spectrum wireless PBX
US4724435A (en) * 1985-11-06 1988-02-09 Applied Spectrum Technologies, Inc. Bi-directional data telemetry system
US4703474A (en) * 1986-02-28 1987-10-27 American Telephone And Telegraph Company, At&T Bell Laboratories Spread spectrum code-division-multiple-access (SS-CDMA) lightwave communication system
US4837786A (en) * 1986-08-07 1989-06-06 Comstream Corporation Technique for mitigating rain fading in a satellite communications system using quadrature phase shift keying
US4807222A (en) * 1986-08-25 1989-02-21 American Telephone And Telegraph Company At&T Bell Laboratories Cordless accessed high-speed high-capacity local area networks
US4901307A (en) * 1986-10-17 1990-02-13 Qualcomm, Inc. Spread spectrum multiple access communication system using satellite or terrestrial repeaters
US4804938A (en) * 1986-10-24 1989-02-14 Sangamo Weston, Inc. Distribution energy management system
US4759034A (en) * 1986-12-02 1988-07-19 General Research Of Electronics, Inc. Multi-step spread spectrum communication apparatus
US4811357A (en) * 1988-01-04 1989-03-07 Paradyne Corporation Secondary channel for digital modems using spread spectrum subliminal induced modulation
US4805208A (en) * 1988-01-15 1989-02-14 Niravoice, Inc. Modem compression system for telephone network
GB2220824A (en) * 1988-07-13 1990-01-17 Philips Electronic Associated Transmission system for sending two signals simultaneously on the same communications channel
CH676179A5 (en) * 1988-09-29 1990-12-14 Ascom Zelcom Ag
JP2718978B2 (en) * 1989-03-02 1998-02-25 株式会社トキメック Data transmission method
US5146471A (en) * 1989-03-23 1992-09-08 Echelon Systems Corporation Correlator for spread spectrum communications systems
US4943973A (en) * 1989-03-31 1990-07-24 At&T Company Spread-spectrum identification signal for communications system
AU619105B2 (en) * 1989-04-21 1992-01-16 Kokusai Denshin Denwa Co. Ltd. Hybrid modulation satellite communication system
US5022047A (en) * 1989-08-07 1991-06-04 Omnipoint Data Corporation Spread spectrum correlator
US5016255A (en) * 1989-08-07 1991-05-14 Omnipoint Data Company, Incorporated Asymmetric spread spectrum correlator
US5025452A (en) * 1990-03-20 1991-06-18 Andrew Corporation Full-duplex, sub-band spread spectrum communications system
US5166952A (en) * 1990-05-24 1992-11-24 Cylink Corporation Method and apparatus for the reception and demodulation of spread spectrum radio signals
US5157686A (en) * 1990-05-24 1992-10-20 Cylink Corporation Method and apparatus for the modulation of spread spectrum radio signals
US5253268A (en) * 1990-05-24 1993-10-12 Cylink Corporation Method and apparatus for the correlation of sample bits of spread spectrum radio signals
US5103459B1 (en) * 1990-06-25 1999-07-06 Qualcomm Inc System and method for generating signal waveforms in a cdma cellular telephone system
US5081642A (en) * 1990-08-06 1992-01-14 Omnipoint Data Company, Incorporated Reciprocal saw correlator method and apparatus
US5093840A (en) * 1990-11-16 1992-03-03 Scs Mobilecom, Inc. Adaptive power control for a spread spectrum transmitter
US5299226A (en) * 1990-11-16 1994-03-29 Interdigital Technology Corporation Adaptive power control for a spread spectrum communications system and method
EP0486834B1 (en) * 1990-11-22 1995-11-22 Ascom Tech Ag Multi-access method and mobile radiocommunication system implementing said multi-access method
DE59104600D1 (en) * 1990-11-22 1995-03-23 Ascom Tech Ag Receiver for a DSSS signal.
US5228056A (en) * 1990-12-14 1993-07-13 Interdigital Technology Corporation Synchronous spread-spectrum communications system and method
US5274665A (en) * 1990-12-14 1993-12-28 Interdigital Technology Corporation Polyopoly overlapping spread spectrum communication system and method
WO1992021195A1 (en) * 1991-05-13 1992-11-26 Omnipoint Corporation Dual mode transmitter and receiver
US5177766A (en) * 1991-06-03 1993-01-05 Spectralink Corporation Digital clock timing generation in a spread-spectrum digital communication system
US5179571A (en) * 1991-07-10 1993-01-12 Scs Mobilecom, Inc. Spread spectrum cellular handoff apparatus and method
JP2554219B2 (en) * 1991-11-26 1996-11-13 日本電信電話株式会社 Digital signal superposition transmission method
ZA931077B (en) * 1992-03-05 1994-01-04 Qualcomm Inc Apparatus and method for reducing message collision between mobile stations simultaneously accessing a base station in a cdma cellular communications system
US5299227A (en) * 1993-04-13 1994-03-29 American Electronics, Inc. Individual beacon identification system
MY112371A (en) * 1993-07-20 2001-05-31 Qualcomm Inc System and method for orthogonal spread spectrum sequence generation in variable data rate systems
US5436941A (en) * 1993-11-01 1995-07-25 Omnipoint Corporation Spread spectrum spectral density techniques
US5383219A (en) * 1993-11-22 1995-01-17 Qualcomm Incorporated Fast forward link power control in a code division multiple access system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4774715A (en) * 1987-03-11 1988-09-27 Telesystems Slw Inc. Device for demodulating a spread spectrum signal
US5150377A (en) * 1990-11-02 1992-09-22 At&T Bell Laboratories Direct sequence spread spectrum (dsss) communications system with frequency modulation utilized to achieve spectral spreading

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP0727111A4 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1029398B1 (en) * 1997-10-10 2009-11-25 QUALCOMM Incorporated Multi-layered pn code spreading in a multi-user communications system
GB2340700A (en) * 1998-08-13 2000-02-23 Ramar Technology Ltd A technique to extend the jamming margin of a DSSS communication system
GB2340700B (en) * 1998-08-13 2000-07-12 Ramar Technology Ltd A technique to extend the jamming margin of a DSSS communication system
US6442191B1 (en) 1998-08-13 2002-08-27 Advanced Technology Ramar Ltd. Technique to extend the jamming margin of a DSSS communication system

Also Published As

Publication number Publication date
KR960706233A (en) 1996-11-08
US5604767A (en) 1997-02-18
CA2174647A1 (en) 1995-05-11
EP0727111A1 (en) 1996-08-21
JPH09504670A (en) 1997-05-06
EP0727111A4 (en) 1998-01-07
US5436941A (en) 1995-07-25
IL111470A0 (en) 1994-12-29
IL111470A (en) 1997-08-14

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