WO1996037066A1 - Doubly orthogonal code and frequency division multiple access communication system - Google Patents

Doubly orthogonal code and frequency division multiple access communication system Download PDF

Info

Publication number
WO1996037066A1
WO1996037066A1 PCT/US1996/006874 US9606874W WO9637066A1 WO 1996037066 A1 WO1996037066 A1 WO 1996037066A1 US 9606874 W US9606874 W US 9606874W WO 9637066 A1 WO9637066 A1 WO 9637066A1
Authority
WO
WIPO (PCT)
Prior art keywords
orthogonal
signal
code
ocdma
communication system
Prior art date
Application number
PCT/US1996/006874
Other languages
French (fr)
Inventor
Francis D. Natali
Original Assignee
Stanford Telecommunications, Inc.
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 Stanford Telecommunications, Inc. filed Critical Stanford Telecommunications, Inc.
Priority to EP96916463A priority Critical patent/EP0829155B1/en
Priority to AU59204/96A priority patent/AU710269B2/en
Priority to DE69632954T priority patent/DE69632954T2/en
Priority to JP53498196A priority patent/JP2003505005A/en
Priority to BR9608879A priority patent/BR9608879A/en
Priority to AT96916463T priority patent/ATE271739T1/en
Publication of WO1996037066A1 publication Critical patent/WO1996037066A1/en

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/30—Systems using multi-frequency codes wherein each code element is represented by a combination of frequencies
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/204—Multiple access
    • H04B7/216—Code division or spread-spectrum multiple access [CDMA, SSMA]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
    • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
    • H04B7/2628—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA]
    • H04B7/2634—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] for channel frequency control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/02—Channels characterised by the type of signal
    • H04L5/023—Multiplexing of multicarrier modulation signals
    • H04L5/026—Multiplexing of multicarrier modulation signals using code division

Definitions

  • Orthogonal code division multiple access has been proposed (see U.S. Patent No. 5,375,140 "WIRELESS DIRECT SEQUENCE SPREAD SPECTRUM DIGITAL CELLULAR TELEPHONE SYSTEM", and U.S. Serial No. 08/257,324, filed June 7, 1994, incorporated herein by reference) as an effective technique for improving the capacity, i.e., bandwidth efficiency, of the more conventional quasi- orthogonal CDMA.
  • PN codes are quasi- orthogonal, i.e. they have relatively low but nonzero cross- correlation values with each other.
  • each user is assigned a code which is orthogonal to all of the other user codes (i.e. the orthogonal codes have a cross-correlation value of zero with each other).
  • the orthogonal code period is chosen such that the code repeats an integer number of times (usually once) in data symbol time.
  • the code epoch is synchronized with the symbol transitions so that no data transitions occur within the code.
  • the number of users is limited by the number of orthogonal functions available, which for binary codes is equal, at most, to the length of the code.
  • An example is the set of Radamacher- ⁇
  • n is a positive integer. Note that the chipping rate is equal to the maximum number of orthogonal users times the symbol rate. This implies that a high data rate requires a much higher chipping rate.
  • OCDMA systems are designed such that all signals are received in time and frequency synchronism. Thus all users remain orthogonal to each other and,in an ideal world, any user can be recovered with no multiple access noise from other users. This is most practical in a star configured network where a multiplicity of users transmit to and receive from a single hub station. This configuration is often used in satellite networks.
  • multiple OCDMA signals be transmitted on orthogonally spaced carriers (i.e. spaced at the chipping rate) and the data from a single user is demultiplexed onto the multiple carriers. In this way, the chipping rate is reduced by the number of carriers.
  • Serial No. in that it employs multiple OCDMA signals transmitted on orthogonally spaced frequencies.
  • a single user transmits on only a single orthogonal function on a single frequency. That is, the system can accommodate a total number of users equal to the product of the number of orthogonal functions and the number of carriers.
  • Another way to view this is that the system utilizes both time and frequency orthogonal properties of waveforms, thus the name "Doubly Orthogonal CDMA (DOCDMA)".
  • DOCDMA Doubly Orthogonal CDMA
  • the chipping rate is reduced by the number of carries compared to strict OCDMA. This has several benefits including:
  • Multipath delay spread causes less access noise due to longer chip period.
  • an orthogonal code division multiple access (OCDMA) terrestrial or satellite based communication system having at least one base station and a plurality of remote subscriber terminals, the sensitivity of OCDMA to access noise due to time base error and multipath delay spread is reduced by reducing the size of the orthogonal signal set on a single carrier (and thus the number of subscribers that can be assigned to that frequency) and employing additional carriers with orthogonal frequency spacing for additional subscriber capacity. This produces a doubly orthogonal code and frequency division multiple access communication system.
  • OCDMA orthogonal code division multiple access
  • FIG. 1A is a block diagram of a satellite based OCDMA communication system incorporating the invention
  • FIG. IB is a block diagram of a terrestrial based OCDMA communication system incorporating the invention.
  • FIG. 2 is a block diagram of a transmitter for a doubly orthogonal code multiple access system (DOCDMA) incorporating the invention
  • FIG. 3 illustrates the composite spectrum for DOCDMA signals
  • FIG. 4 is a functional block diagram for a DOCDMA receiver incorporating the invention.
  • this invention is an extension of the OCDMA multicarrier scheme of U.S. Patent Application Serial No. , , in that it employs multiple OCDMA signals transmitted on orthogonally spaced frequencies.
  • a single user transmits on only a single orthogonal function on a single frequency.
  • FIG. 2 An embodiment of the transmitter is shown in Fig. 2.
  • the input data from source 10 is buffered and formatted 11 and then is modulated on a carrier using MPSK modulation, where M is >.2.
  • M is >.2.
  • FEC Forward Error Correction
  • the signal is then BPSK modulated with a binary sequence which is the Mod-2 sum 16 of a PN sequence from PN generator 14 and one member of a set of binary sequences which are orthogonal over a symbol period.
  • RW Radamacher-Walsh
  • the same PN code is employed by each of the members of a single "cell" or orthogonal set.
  • the PN clock rate from timing logic circuit 17 which is drive by clock 18 is usually selected to be the same as the RW chip rate, although this is not necessary.
  • a system synchronizing signal to timing logic circuit 17 and a frequency select signal to conventional carrier synthesizer 19 The signal waveform from BPSK modulator is up-converted 20, power amplifier 21 and broadcast by antenna 22.
  • each user is assigned a code which is orthogonal to all of the other user codes (i.e. the orthogonal codes have a cross-correlation value of zero with each other) .
  • the orthogonal code period is chosen such that the code repeats an integer number of times (usually once) in a data symbol time.
  • the code epoch is synchronized with the symbol transitions so that no data transitions occur within the code.
  • the RAW chipping rate is equal to the maximum number of orthogonal users times the symbol rate.
  • the modulated carrier frequency is selected from one of N frequencies which are orthogonal over a RW chip interval,i.e. the carrier frequencies are spaced by the RW chipping rate.
  • the composite signal is up-converted to the appropriate frequency band for transmission.
  • the individual transmissions are synchronized to arrive at the base station in time and frequency synchronism.
  • the resulting received spectrum is as shown in Fig. 3 for the case where the chipping rate is 166.4 kHz and five orthogonal carriers are employed.
  • a block diagram of the DOCDMA receiver is shown in Fig. 4.
  • the signals received on antenna 23 signals are down converted 24 to I,Q baseband and converted from analog to digital samples 251, 25Q and for processing.
  • Tracking loops are employed to estimate received carrier frequency and code phase.
  • the code phase tracking loop includes code phase discriminator 30, filter 31, number controlled oscillator 32, which controls PN generator 34 and RW generator 35 which generate the respective PN and RW functions.
  • Receiver controller CR provides an RW select signal to RW generator 35 to select a particular RW function.
  • the PN and RW functions are combined 36 and applied to mixer 37.
  • the carrier tracking loop incorporates a carrier frequency discriminator 38, filter 39.
  • the carrier frequency select from receiver controller CR is selected 40, the carrier frequency via number controller oscillator 41.
  • the quadrative (cos, sin) signals from NCO 41 are applied to complex multiplier 28 to close the carrier tracking loop.
  • QPSK demodulation 42 is performed in the usual way employing either coherent or differentially

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Radio Relay Systems (AREA)
  • Reduction Or Emphasis Of Bandwidth Of Signals (AREA)
  • Transmitters (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
  • Selective Calling Equipment (AREA)

Abstract

In an orthogonal code division multiple access (OCDMA) radio communication system having at least one base station and a plurality of remote subscriber terminals, the improvement comprising the method of reducing the sensitivity of OCDMA to access noise due to time base error and multipath delay spread comprising reducing the size of the orthogonal signal set on a single carrier (15), and providing additional carriers with orthogonal frequency spacing for additional subscriber capacity (12, 19).

Description

DOUBLY ORTHOGONAL CODE AND FREQUENCY DIVISION MULTIPLE ACCESS COMMUNICATION SYSTEM
BACKGROUND OF THE INVENTION;
Spread spectrum communications is being used for a number of commercial applications and is proliferating at a rapid rate. Orthogonal code division multiple access (OCDMA) has been proposed (see U.S. Patent No. 5,375,140 "WIRELESS DIRECT SEQUENCE SPREAD SPECTRUM DIGITAL CELLULAR TELEPHONE SYSTEM", and U.S. Serial No. 08/257,324, filed June 7, 1994, incorporated herein by reference) as an effective technique for improving the capacity, i.e., bandwidth efficiency, of the more conventional quasi- orthogonal CDMA.
In conventional direct sequence (DS) spread spectrum CDMA systems, the individual users transmit on the same frequency using different pseudo-noise (PN) codes. The PN codes are quasi- orthogonal, i.e. they have relatively low but nonzero cross- correlation values with each other.
In an OCDMA system, each user is assigned a code which is orthogonal to all of the other user codes (i.e. the orthogonal codes have a cross-correlation value of zero with each other). Further, the orthogonal code period is chosen such that the code repeats an integer number of times (usually once) in data symbol time. The code epoch is synchronized with the symbol transitions so that no data transitions occur within the code. The number of users is limited by the number of orthogonal functions available, which for binary codes is equal, at most, to the length of the code. An example is the set of Radamacher- μ
Walsh functions for which there are 2"' orthogonal functions of length 2" where n is a positive integer. Note that the chipping rate is equal to the maximum number of orthogonal users times the symbol rate. This implies that a high data rate requires a much higher chipping rate.
OCDMA systems are designed such that all signals are received in time and frequency synchronism. Thus all users remain orthogonal to each other and,in an ideal world, any user can be recovered with no multiple access noise from other users. This is most practical in a star configured network where a multiplicity of users transmit to and receive from a single hub station. This configuration is often used in satellite networks.
There are, of course, a number of practical considerations and real-world effects that cause OCDMA performance to degrade from ideal. For example, multipath returns that are delayed a significant portion of a chip are no longer truly orthogonal and cause access noise. This is a problem for high data rate systems, since the chipping rate is correspondingly higher, and the multipath delay spread becomes increasingly significant. A technique for combating this effect is disclosed in Magill U.S. Patent Application Serial No. 08/352,313, filed December 8, 1994 entitled "ORTHOGONAL CODE DIVISION MULTIPLE ACCESS COMMUNICATION SYSTEM HAVING MULTICARRIER MODULATION", also incorporated herein by reference. In this application, it is disclosed that multiple OCDMA signals be transmitted on orthogonally spaced carriers (i.e. spaced at the chipping rate) and the data from a single user is demultiplexed onto the multiple carriers. In this way, the chipping rate is reduced by the number of carriers.
OBJECTS OF THE INVENTION:
The invention described below is an extension of the OCDMA multicarrier invention disclosed in U.S. Patent Application
Serial No. , in that it employs multiple OCDMA signals transmitted on orthogonally spaced frequencies. In this case, however, a single user transmits on only a single orthogonal function on a single frequency. That is, the system can accommodate a total number of users equal to the product of the number of orthogonal functions and the number of carriers. Another way to view this is that the system utilizes both time and frequency orthogonal properties of waveforms, thus the name "Doubly Orthogonal CDMA (DOCDMA)". For a given number of users, the chipping rate is reduced by the number of carries compared to strict OCDMA. This has several benefits including:
• Much easier to acquire due to the lower chipping rate.
• Multipath delay spread causes less access noise due to longer chip period.
• More uniform power spectral density.
• Higher bandwidth efficiency. • Lower receiver power dissipation due to lower clocking rates.
The above attributes made multicarrier OCDMA very attractive for satellite networks with a multiplicity of mobile users, such as those that support personal communications.
SUMMARY OF THE INVENTION:
According to the invention, an orthogonal code division multiple access (OCDMA) terrestrial or satellite based communication system is provided having at least one base station and a plurality of remote subscriber terminals, the sensitivity of OCDMA to access noise due to time base error and multipath delay spread is reduced by reducing the size of the orthogonal signal set on a single carrier (and thus the number of subscribers that can be assigned to that frequency) and employing additional carriers with orthogonal frequency spacing for additional subscriber capacity. This produces a doubly orthogonal code and frequency division multiple access communication system.
DESCRIPTION OF THE INVENTION:
The above and other objects, advantages and features of the invention will become more apparent when considered with the following specification and accompanying drawings wherein: FIG. 1A is a block diagram of a satellite based OCDMA communication system incorporating the invention,
FIG. IB is a block diagram of a terrestrial based OCDMA communication system incorporating the invention,
FIG. 2 is a block diagram of a transmitter for a doubly orthogonal code multiple access system (DOCDMA) incorporating the invention,
FIG. 3 illustrates the composite spectrum for DOCDMA signals, and
FIG. 4 is a functional block diagram for a DOCDMA receiver incorporating the invention.
DETAILED DESCRIPTION OF THE INVENTION:
As mentioned above, this invention is an extension of the OCDMA multicarrier scheme of U.S. Patent Application Serial No. , , in that it employs multiple OCDMA signals transmitted on orthogonally spaced frequencies. In the present invention, however, a single user transmits on only a single orthogonal function on a single frequency.
An embodiment of the transmitter is shown in Fig. 2. The input data from source 10 is buffered and formatted 11 and then is modulated on a carrier using MPSK modulation, where M is >.2. One would typically use M=4, i.e. QPSK modulation. Forward Error Correction (FEC) coding and interleaving may also be employed, depending on the application. The signal is then BPSK modulated with a binary sequence which is the Mod-2 sum 16 of a PN sequence from PN generator 14 and one member of a set of binary sequences which are orthogonal over a symbol period. The Radamacher-Walsh (RW) functions 15, for which there are 2 orthogonal functions of length 2*' where n is a positive integer, will be assumed here for illustrative purposes. An RW function select signal from controller C selects the desired member of the set of RW sequences for Mod-2 summing with the selected PN code.
The same PN code is employed by each of the members of a single "cell" or orthogonal set. The PN clock rate from timing logic circuit 17 which is drive by clock 18 is usually selected to be the same as the RW chip rate, although this is not necessary.
A system synchronizing signal to timing logic circuit 17 and a frequency select signal to conventional carrier synthesizer 19. The signal waveform from BPSK modulator is up-converted 20, power amplifier 21 and broadcast by antenna 22.
As mentioned above, each user is assigned a code which is orthogonal to all of the other user codes (i.e. the orthogonal codes have a cross-correlation value of zero with each other) . Further, the orthogonal code period is chosen such that the code repeats an integer number of times (usually once) in a data symbol time. The code epoch is synchronized with the symbol transitions so that no data transitions occur within the code. Note that the RAW chipping rate is equal to the maximum number of orthogonal users times the symbol rate.
The modulated carrier frequency is selected from one of N frequencies which are orthogonal over a RW chip interval,i.e. the carrier frequencies are spaced by the RW chipping rate. The composite signal is up-converted to the appropriate frequency band for transmission.
The individual transmissions are synchronized to arrive at the base station in time and frequency synchronism. The resulting received spectrum is as shown in Fig. 3 for the case where the chipping rate is 166.4 kHz and five orthogonal carriers are employed.
A block diagram of the DOCDMA receiver is shown in Fig. 4. The signals received on antenna 23 signals are down converted 24 to I,Q baseband and converted from analog to digital samples 251, 25Q and for processing. Tracking loops are employed to estimate received carrier frequency and code phase. The code phase tracking loop includes code phase discriminator 30, filter 31, number controlled oscillator 32, which controls PN generator 34 and RW generator 35 which generate the respective PN and RW functions. Receiver controller CR provides an RW select signal to RW generator 35 to select a particular RW function. The PN and RW functions are combined 36 and applied to mixer 37. The carrier tracking loop incorporates a carrier frequency discriminator 38, filter 39. The carrier frequency select from receiver controller CR is selected 40, the carrier frequency via number controller oscillator 41. The quadrative (cos, sin) signals from NCO 41 are applied to complex multiplier 28 to close the carrier tracking loop. QPSK demodulation 42 is performed in the usual way employing either coherent or differentially coherent detection to provide the data to a utilization device 43.
While preferred embodiments of the invention have been shown and illustrated, it will be appreciated that other embodiments will be readily apparent to those skilled in the art and be encompassed by the claims appended hereto.
WHAT IS CLAIMED IS:

Claims

1. An orthogonal code division multiple access (OCDMA) radio communication system having at least one base station and a plurality of remote subscriber terminals and modulator, a source of orthogonal function code sets, means for reducing the size of the orthogonal signal set on a single carrier and means for employing additional carriers with orthogonal frequency spacing for additional subscriber capacity to reduce the sensitivity of OCDMA to access noise due to time base error and multipath delay spread.
2. The radio communication system defined iri claim 1 wherein said at least one base station is located terrestrially.
3. The radio communication system defined in claim 1 including a communications satellite and wherein said at least one base station communicates with said remote subscriber terminals via said communications satellite.
4. An orthogonal code division multiple access (OCDMA) radio communication system having at least one base station and a plurality of subscriber/user terminals, for communicating data, a transmitter means including:
MPSK modulator means connected to receive said data, a biphase modulator (BPSK) means connected to said MPSK modulator. a carrier frequency synthesizer connected to said MPSK modulator generating selectable carrier frequencies which are spaced by the RW chipping rate, an RW function set generator having means to select a given RW function set, a PN code generator to provide a selected PN code signal, means for summing a selected given RW function signal set with said PN code signal, said selected RW function set being one member of a set binary sequences which are orthogonal over a symbol period, and means to up-convert the composite signal from said biphase modulator to a broadcast frequency band for transmission.
5. The system defined in claim 4 including receiver means for receiving and demodulating said composite signal to recover said data.
6. The system defined in claim 5 wherein said receiver means includes: second PN generator means to provide a second PN code signal, second RW function generator means to provide a second RW function signal set, means to sum said second PN code and RW function set signals to provide despreading and decoding signal. a code phase tracking loop having an NCO controlling said second PN generator means and said second RW function generator means, mixer means for receiving said composite signal and said despreading and decoding signal to produce a despreading and decoded output signal, and a carrier frequency tracking loop having an NCO and means for selecting a specific carrier frequency.
7. In an orthogonal code division multiple access (OCDMA) radio communication system having at least one base station and a plurality of remote subscriber terminals, the improvement comprising the method of reducing the sensitivity of OCDMA to access noise due to time base error and multipath delay spread comprising (1) reducing the size of the orthogonal signal set on a single carrier, and (2) providing additional carriers with orthogonal frequency spacing for additional subscriber capacity.
PCT/US1996/006874 1995-05-19 1996-05-17 Doubly orthogonal code and frequency division multiple access communication system WO1996037066A1 (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
EP96916463A EP0829155B1 (en) 1995-05-19 1996-05-17 Doubly orthogonal code and frequency division multiple access communication system
AU59204/96A AU710269B2 (en) 1995-05-19 1996-05-17 Doubly orthogonal code and frequency division multiple access communication system
DE69632954T DE69632954T2 (en) 1995-05-19 1996-05-17 Radio communication system with multiple access in orthogonal code division multiplex technology
JP53498196A JP2003505005A (en) 1995-05-19 1996-05-17 Double orthogonal code and frequency division multiple access communication system
BR9608879A BR9608879A (en) 1995-05-19 1996-05-17 Multiple access communication system by frequency division and double orthogonal code
AT96916463T ATE271739T1 (en) 1995-05-19 1996-05-17 DOUBLE ORTHOGONAL CODE AND MULTIPLE ACCESS SWITCHING SYSTEM THROUGH FREQUENCY DISTRIBUTION

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US08/444,749 1995-05-19
US08/444,749 US5623487A (en) 1995-05-19 1995-05-19 Doubly orthogonal code and frequency division multiple access communication system

Publications (1)

Publication Number Publication Date
WO1996037066A1 true WO1996037066A1 (en) 1996-11-21

Family

ID=23766196

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1996/006874 WO1996037066A1 (en) 1995-05-19 1996-05-17 Doubly orthogonal code and frequency division multiple access communication system

Country Status (10)

Country Link
US (1) US5623487A (en)
EP (1) EP0829155B1 (en)
JP (1) JP2003505005A (en)
KR (1) KR100426543B1 (en)
AT (1) ATE271739T1 (en)
AU (1) AU710269B2 (en)
BR (1) BR9608879A (en)
CA (1) CA2221101A1 (en)
DE (1) DE69632954T2 (en)
WO (1) WO1996037066A1 (en)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2320660A (en) * 1996-12-20 1998-06-24 Dsc Telecom Lp Processing data transmitted and received over a wireless link connecting a central terminal and a subscriber terminal of a wireless telecommunication system
GB2320661B (en) * 1996-12-20 2001-10-03 Dsc Telecom Lp Processing data transmitted and received over a wireless link connecting a central terminal and a subscriber terminal of a wireless telecommunications system
WO2004004269A1 (en) * 2002-06-27 2004-01-08 Nortel Networks Limited Dual-mode shared ofdm methods/transmitters, receivers and systems
JP2008062072A (en) * 2001-01-02 2008-03-21 Abbott Diabetes Care Inc Analyte monitoring device, manufacturing method of analyte monitoring device, and method of transmitting digital signal
EP1919152A3 (en) * 2002-06-27 2009-07-08 Nortel Networks Limited Dual-mode shared OFDM methods/transmitters, receivers and systems
US8880137B2 (en) 1998-04-30 2014-11-04 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US8915850B2 (en) 2005-11-01 2014-12-23 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US8920319B2 (en) 2005-11-01 2014-12-30 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US8974386B2 (en) 1998-04-30 2015-03-10 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US9066695B2 (en) 1998-04-30 2015-06-30 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US9078607B2 (en) 2005-11-01 2015-07-14 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US10478108B2 (en) 1998-04-30 2019-11-19 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use

Families Citing this family (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5832035A (en) 1994-09-20 1998-11-03 Time Domain Corporation Fast locking mechanism for channelized ultrawide-band communications
US7321611B2 (en) 1994-09-20 2008-01-22 Alereen, Inc. Method and transceiver for full duplex communication of ultra wideband signals
US5677927A (en) 1994-09-20 1997-10-14 Pulson Communications Corporation Ultrawide-band communication system and method
US5790588A (en) * 1995-06-07 1998-08-04 Ntt Mobile Communications Network, Inc. Spread spectrum transmitter and receiver employing composite spreading codes
US6330291B1 (en) * 1996-03-29 2001-12-11 Qualcomm Inc. Frequency tracking for communication signals using M-ary orthogonal walsh modulation
US5825812A (en) * 1996-06-06 1998-10-20 Wireless Logic, Inc. Suppressed side lobe direct-sequence-spread-spectrum radio communication method and device
US5930309A (en) * 1997-02-27 1999-07-27 Thomson Consumer Electronics, Inc. Receiver signal processing system for cap signals
US5953327A (en) * 1996-10-29 1999-09-14 Stanford Telecommunications, Inc. Class of low cross correlation non-palindromic synchronization sequences for code tracking in synchronous multiple access communication systems
US7539237B2 (en) 1996-12-06 2009-05-26 Alereon, Inc. Fast locking mechanism for channelized ultrawide-band communications
US6104708A (en) * 1997-08-11 2000-08-15 Bbn Corporation Wireless data communications system
KR100365346B1 (en) * 1997-09-09 2003-04-11 삼성전자 주식회사 Apparatus and method for generating quasi-orthogonal code of mobile communication system and diffusing band by using quasi-orthogonal code
JP3364419B2 (en) 1997-10-29 2003-01-08 新キャタピラー三菱株式会社 Remote radio control system, remote control device, mobile relay station and wireless mobile work machine
US6075781A (en) * 1997-12-12 2000-06-13 Stanford Telecommunications, Inc. Flux density reduction in OCDMA satellite communication system
US6570844B1 (en) 1997-12-29 2003-05-27 Alcatel Usa Sourcing, L.P. System and method for providing redundancy in a telecommunications system
US6408019B1 (en) 1997-12-29 2002-06-18 Georgia Tech Research Corporation System and method for communication using noise
US6512755B1 (en) 1997-12-29 2003-01-28 Alcatel Usa Sourcing, L.P. Wireless telecommunications access system
US7027484B1 (en) 1998-07-10 2006-04-11 Qualcomm Incorporated Method and apparatus for transmitting and receiving high speed data using code division multiple access channels
US6711120B1 (en) * 1999-03-11 2004-03-23 Flarion Technologies, Inc. Orthogonal frequency division multiplexing based spread spectrum multiple access
KR100306083B1 (en) * 1999-06-29 2001-11-01 김대기 Apparatus and method for changing carrier for mobile communication with switching function
US7092440B1 (en) * 2000-09-27 2006-08-15 Ut-Battelle Llc Hybrid spread-spectrum technique for expanding channel capacity
US7315563B2 (en) * 2003-12-03 2008-01-01 Ut-Battelle Llc Multicarrier orthogonal spread-spectrum (MOSS) data communications
US7340001B2 (en) * 2003-12-03 2008-03-04 Ut-Battelle Llc Multidimensional signal modulation and/or demodulation for data communications
US7656931B2 (en) 2003-12-31 2010-02-02 Ut-Battelle, Llc Hybrid spread spectrum radio system

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5103459A (en) * 1990-06-25 1992-04-07 Qualcomm Incorporated System and method for generating signal waveforms in a cdma cellular telephone system

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5375140A (en) * 1992-11-24 1994-12-20 Stanford Telecommunications, Inc. Wireless direct sequence spread spectrum digital cellular telephone system
US5375146A (en) * 1993-05-06 1994-12-20 Comsat Corporation Digital frequency conversion and tuning scheme for microwave radio receivers and transmitters

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5103459A (en) * 1990-06-25 1992-04-07 Qualcomm Incorporated System and method for generating signal waveforms in a cdma cellular telephone system
US5103459B1 (en) * 1990-06-25 1999-07-06 Qualcomm Inc System and method for generating signal waveforms in a cdma cellular telephone system

Cited By (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2320660A (en) * 1996-12-20 1998-06-24 Dsc Telecom Lp Processing data transmitted and received over a wireless link connecting a central terminal and a subscriber terminal of a wireless telecommunication system
US6222819B1 (en) 1996-12-20 2001-04-24 Airspan Networks, Inc. Processing data transmitted and received over a wireless link connecting a central terminal and a subscriber terminal of a wireless telecommunications system
GB2320661B (en) * 1996-12-20 2001-10-03 Dsc Telecom Lp Processing data transmitted and received over a wireless link connecting a central terminal and a subscriber terminal of a wireless telecommunications system
US6381211B1 (en) 1996-12-20 2002-04-30 Airspan Networks Inc. Processing data transmitted and received over a wireless link connecting a central terminal and a subscriber terminal of a wireless telecommunications system
US9066697B2 (en) 1998-04-30 2015-06-30 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US9066694B2 (en) 1998-04-30 2015-06-30 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US10478108B2 (en) 1998-04-30 2019-11-19 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US9072477B2 (en) 1998-04-30 2015-07-07 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US8880137B2 (en) 1998-04-30 2014-11-04 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US9066695B2 (en) 1998-04-30 2015-06-30 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US9011331B2 (en) 1998-04-30 2015-04-21 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US8974386B2 (en) 1998-04-30 2015-03-10 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US9014773B2 (en) 1998-04-30 2015-04-21 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US9498159B2 (en) 2001-01-02 2016-11-22 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US9011332B2 (en) 2001-01-02 2015-04-21 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
JP2008062072A (en) * 2001-01-02 2008-03-21 Abbott Diabetes Care Inc Analyte monitoring device, manufacturing method of analyte monitoring device, and method of transmitting digital signal
US9610034B2 (en) 2001-01-02 2017-04-04 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US7551546B2 (en) 2002-06-27 2009-06-23 Nortel Networks Limited Dual-mode shared OFDM methods/transmitters, receivers and systems
WO2004004269A1 (en) * 2002-06-27 2004-01-08 Nortel Networks Limited Dual-mode shared ofdm methods/transmitters, receivers and systems
EP1919152A3 (en) * 2002-06-27 2009-07-08 Nortel Networks Limited Dual-mode shared OFDM methods/transmitters, receivers and systems
US11911151B1 (en) 2005-11-01 2024-02-27 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US8915850B2 (en) 2005-11-01 2014-12-23 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US8920319B2 (en) 2005-11-01 2014-12-30 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US10231654B2 (en) 2005-11-01 2019-03-19 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US10201301B2 (en) 2005-11-01 2019-02-12 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US9326716B2 (en) 2005-11-01 2016-05-03 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US10952652B2 (en) 2005-11-01 2021-03-23 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US11103165B2 (en) 2005-11-01 2021-08-31 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US11272867B2 (en) 2005-11-01 2022-03-15 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US11363975B2 (en) 2005-11-01 2022-06-21 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US11399748B2 (en) 2005-11-01 2022-08-02 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use
US9078607B2 (en) 2005-11-01 2015-07-14 Abbott Diabetes Care Inc. Analyte monitoring device and methods of use

Also Published As

Publication number Publication date
KR19990014914A (en) 1999-02-25
KR100426543B1 (en) 2004-06-16
ATE271739T1 (en) 2004-08-15
MX9708913A (en) 1998-06-30
US5623487A (en) 1997-04-22
EP0829155A1 (en) 1998-03-18
EP0829155A4 (en) 2003-01-22
AU5920496A (en) 1996-11-29
DE69632954T2 (en) 2005-07-28
AU710269B2 (en) 1999-09-16
BR9608879A (en) 1999-07-06
EP0829155B1 (en) 2004-07-21
DE69632954D1 (en) 2004-08-26
CA2221101A1 (en) 1996-11-21
JP2003505005A (en) 2003-02-04

Similar Documents

Publication Publication Date Title
US5623487A (en) Doubly orthogonal code and frequency division multiple access communication system
US5687166A (en) Modulation system for spread spectrum CDMA communication
US5414728A (en) Method and apparatus for bifurcating signal transmission over in-phase and quadrature phase spread spectrum communication channels
CA2194659C (en) Multipath resistant, orthogonal code-division multiple access system
EP0727116B1 (en) Variable rate signal transmission in a spread spectrum communication system using coset coding
US5729570A (en) Orthogonal code division multiple access communication system having multicarrier modulation
RU2313176C2 (en) Client block and method for using it in a wireless communication system
US5920551A (en) Channel structure with burst pilot in reverse link
EP1040590B1 (en) Increased capacity in an ocdma system by frequency isolation
US9467200B2 (en) Method and apparatus for orthogonally overlaying variable chip rate spread spectrum signals
EP0878077A4 (en) Forward link carrier recovery in an ocdma spread spectrum communication system without a pilot tone
US5668795A (en) Modulation system for spread spectrum CDMA communiction
JP2000514992A (en) Time switching transmission diversity apparatus and method for mobile communication system
US7433385B1 (en) Code division multiple access communication
EP0838105B1 (en) Multipath resistant, orthogonal code-division multiple access system
EP1708377B1 (en) Reduced peak-to-average amplitude multichannel
MXPA97008913A (en) Multiple access communication system frequency condivision and double-earth code
Zhang et al. A sequency multiplexing technique for mobile communication systems

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: PA/a/1997/008913

Country of ref document: MX

AK Designated states

Kind code of ref document: A1

Designated state(s): AU BR CA JP KR MX

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
ENP Entry into the national phase

Ref document number: 2221101

Country of ref document: CA

Ref country code: CA

Ref document number: 2221101

Kind code of ref document: A

Format of ref document f/p: F

WWE Wipo information: entry into national phase

Ref document number: 1996916463

Country of ref document: EP

WWE Wipo information: entry into national phase

Ref document number: 1019970708260

Country of ref document: KR

WWP Wipo information: published in national office

Ref document number: 1996916463

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 1019970708260

Country of ref document: KR

WWG Wipo information: grant in national office

Ref document number: 1019970708260

Country of ref document: KR

WWG Wipo information: grant in national office

Ref document number: 1996916463

Country of ref document: EP