USRE37802E1 - Multicode direct sequence spread spectrum - Google Patents

Multicode direct sequence spread spectrum Download PDF

Info

Publication number
USRE37802E1
USRE37802E1 US09/151,604 US15160498D USRE37802E US RE37802 E1 USRE37802 E1 US RE37802E1 US 15160498 D US15160498 D US 15160498D US RE37802 E USRE37802 E US RE37802E
Authority
US
United States
Prior art keywords
data symbols
transceiver
code
modulated data
transform
Prior art date
Legal status (The legal status 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 status listed.)
Expired - Lifetime
Application number
US09/151,604
Inventor
Michel T. Fattouche
Hatim Zaghloul
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Quarterhill Inc
Original Assignee
WiLAN 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
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=57048653&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=USRE37802(E1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Priority claimed from US07/861,725 external-priority patent/US5282222A/en
Priority claimed from US08/186,784 external-priority patent/US5555268A/en
Application filed by WiLAN Inc filed Critical WiLAN Inc
Application granted granted Critical
Publication of USRE37802E1 publication Critical patent/USRE37802E1/en
Assigned to WI-LAN, INC. reassignment WI-LAN, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ENSEMBLE COMMUNICATIONS, INC.
Assigned to WI-LAN, INC. reassignment WI-LAN, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: FATTOUCHE, MICHAEL, ZAGHLOUL, HATIM
Anticipated expiration legal-status Critical
Assigned to QUARTERHILL INC. reassignment QUARTERHILL INC. MERGER AND CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: QUARTERHILL INC., WI-LAN INC.
Assigned to WI-LAN INC. reassignment WI-LAN INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: QUARTERHILL INC.
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J11/00Orthogonal multiplex systems, e.g. using WALSH 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
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J13/00Code division multiplex systems
    • H04J13/0077Multicode, e.g. multiple codes assigned to one user
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00Modulated-carrier systems
    • H04L27/26Systems using multi-frequency codes
    • H04L27/2601Multicarrier modulation systems
    • H04L27/2602Signal structure
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00Modulated-carrier systems
    • H04L27/26Systems using multi-frequency codes
    • H04L27/2601Multicarrier modulation systems
    • H04L27/2626Arrangements specific to the transmitter only
    • H04L27/2627Modulators
    • H04L27/2628Inverse Fourier transform modulators, e.g. inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00Modulated-carrier systems
    • H04L27/26Systems using multi-frequency codes
    • H04L27/2601Multicarrier modulation systems
    • H04L27/2647Arrangements specific to the receiver only
    • H04L27/2649Demodulators
    • H04L27/265Fourier transform demodulators, e.g. fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/02Channels characterised by the type of signal
    • H04L5/023Multiplexing of multicarrier modulation signals
    • H04L5/026Multiplexing of multicarrier modulation signals using code division
    • 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
    • H04B1/709Correlator structure
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B2201/00Indexing scheme relating to details of transmission systems not covered by a single group of H04B3/00 - H04B13/00
    • H04B2201/69Orthogonal indexing scheme relating to spread spectrum techniques in general
    • H04B2201/707Orthogonal indexing scheme relating to spread spectrum techniques in general relating to direct sequence modulation
    • H04B2201/70703Orthogonal indexing scheme relating to spread spectrum techniques in general relating to direct sequence modulation using multiple or variable rates

Definitions

  • the invention deals with the field of multiple access communications using Spread Spectrum modulation.
  • Multiple access can be classified as either random access, polling, TDMA, FDMA, CDMA or any combination thereof.
  • Spread Spectrum can be classified as Direct Sequence, Frequency-Hopping or a combination of the two.
  • DSSS Direct Sequence Spread Spectrum
  • CDMA Code Division Multiple Access
  • DSSS is a communication scheme in which information bits are spread over code bits (generally called chips). It is customary to use noise-like codes called pseudo random noise (PN) sequences.
  • PN sequences have the property that their auto-correlation is almost a delta function and their cross-correlation with other codes is almost null.
  • the transmitted signal can be buried in noise and thus has a low probability of intercept.
  • the receiver can recover the signal from interferers (such as other transmitted codes) with a jamming margin that is proportional to the spreading code length.
  • DSSS codes of duration longer than the delay spread of the propagation channel can lead to multipath diversity implementable using a Rake receiver.
  • the FCC and the DOC have allowed the use of unlicensed low power DSSS systems of code lengths greater than or equal to 10 in some frequency bands (the ISM bands).
  • CDMA Code Division Multiple Access
  • Synchronization of the receiver and the transmitter is complex (especially) if the receiver does not know in advance which code is being transmitted.
  • MC-DSSS Multi-Code Direct Sequence Spread Spectrum
  • MC-DSSS When viewed as DSSS, MC-DSSS requires up to N correlators (or equivalently up to N Matched Filters) at the receiver with a complexity of the order of N 2 operations. When N is large, this complexity is prohibitive.
  • ICI InterCode Interference
  • a nonideal communication channel can cause InterCode Interference (ICI), i.e., interference between the N DSSS codes at the receiver.
  • MC codes InterCode Interference
  • Such codes allow the information in a MC-DSSS signal to be decoded in a sequence of low complexity parallel operations while reducing the ICI.
  • our implementation of MC-DSSS using the MC codes has the following advantages:
  • FIG. 8 is a schematic showing the Randomizer Transform (RT) where a (1) a (2) . . . a (N) are complex constants chosen randomly.
  • FIG. 9 is a schematic showing the Permutation Transform (PT).
  • FIG. 10 is a schematic showing (a) the shaping of a MC-DSSS frame and (b) the unshaping of a MC-DSSS frame
  • v(k) [v(1,k) v(2,k) . . .
  • FIG. 11 is a schematic showing (a) Description of the alias/window operation (b) Description of dealias/dewindow operation, where 1/T is the symbol rate.
  • FIG. 12 is a schematic showing the frame structure for data transmission from source (Node A) to destination (Node B).
  • FIG. 14 is a schematic showing the baseband receiver for the received request frame
  • v′ [v′(1) v′((1+ ⁇ ) MI)], ⁇ (0,1)
  • FIG. 15 is a schematic showing the baseband transmitter for one address frame
  • v [v(1) v(2) . . . v(1+ ⁇ ) MI)]
  • l′ is the length of the CDMA code.
  • FIG. 17 is a schematic showing the baseband transmitter for Ack.
  • FIG. 18 is a schematic showing the baseband receiver for the ack. frame
  • c [c(1) c(2) . . . c(I′′)] is the DSSS code for the Ack. frame
  • d′ [d(1) d(2) . . . d′(I′′)] is the received Ack. frame
  • FIG. 19 is a schematic showing the passband transmitter for a packet where f o is the IF frequency and f o +f c is the RF frequency.
  • FIG. 20 is a schematic showing the passband receiver for a packet where f o is the IF frequency and f o +f c is the RF frequency.
  • FIG. 1 illustrates the transmitter of the MC-DSSS modulation technique generating the kth MC-DSSS frame bearing N symbols of information.
  • the symbols can be either analog or digital.
  • a converter 10 converts a stream of data symbols into plural sets of N data symbols each.
  • a computing means 12 operates on the plural sets of N data symbols to produce modulated data symbols corresponding to an invertible randomized spreading of the stream of data symbols.
  • a combiner 14 combines the modulated data symbols for transmission.
  • the computing means shown in FIG. 1 includes a source 16 of N direct sequence spread spectrum code symbols and a modulator 18 to modulate each ith data symbol from each set of N data symbols with the I code symbol from the N code symbol to generate N modulated data symbols, and thereby spread each I data symbol over a separate code symbol.
  • FIG. 2 illustrates the receiver of the MC-DSSS modulation techniques accepting the kth MC-DSSS frame and generating estimates for the corresponding N symbols of information.
  • the dot product in FIG. 2 can be implemented as a correlator.
  • the detector can make either hard decisions or soft decisions.
  • a sequence of modulated data symbols is received at 22 in which the sequence of modulated data symbols has been generated by the transmitter such as is shown in FIG. 1 or 4 .
  • a second computing means 24 operates on the sequence of modulated data symbols to produce an estimate of the second string of data symbols.
  • the computing means 24 shown in FIG. 2 includes a correlator 26 for correlating each I modulated data symbol from the received sequence of modulated data symbols with the I code symbol from the set of N code symbols and a detector 28 for detecting an estimate of the data symbols from output of the correlator 26 .
  • FIG. 3 illustrates the code generator of the MC codes.
  • Any one of the P N-point transforms in FIG. 3 consists of a reversible transform to the extent of the available arithmetic precision. In other words, with finite precision arithmetic, the transforms are allowed to add a limited amount of irreversible error.
  • FIG. 4 An alternative transmitter to the one in FIG. 1 using the MC codes in FIG. 3 is shown in FIG. 4 .
  • the alternative transmitter shown in FIG. 4 includes a transformer 20 for operating on each set of N data symbols to generate N modulated data symbols as output. A series of transforms are shown.
  • FIG. 5 An alternative receiver to the one in FIG. 2 using the MC codes in FIG. 3 is shown in FIG. 5. L pilots are required in FIG. 5 for equalization.
  • Both transmitters in FIGS. 1 and 4 allow using shaper 30 in diversity module 32 shaping and time diversity of the MC-DSSS signal as shown in FIG. 6 .
  • Both receivers in FIGS. 2 and 5 allow diversity combining followed by the unshaping of the Data frame as shown in FIG. 7.
  • a Synch. is required in FIG. 7 for frame synchronization.
  • Examples of the N-point transforms in FIG. 3 are a Discrete Fourier Transform (DFT), a Fast Fourier Transform (FFT), a Walsh Transform (WT), a Hilbert Transform (HT), a Randomizer Transform (RT) as the one illustrated in FIG. 8, a Permutator Transform (PT) as the one illustrated in FIG. 9, an Inverse DFT (IDFT), an Inverse FFT (IFFT), an Inverse WT (IWT), an Inverse HT (IHT), an Inverse RT (IRT), an Inverse PT (IPT), and any other reversible transform.
  • DFT Discrete Fourier Transform
  • FFT Fast Fourier Transform
  • WT Walsh Transform
  • HT Hilbert Transform
  • RT Randomizer Transform
  • RT Randomizer Transform
  • PT Permutator Transform
  • IFT Inverse DFT
  • IDFT Inverse FFT
  • IWT Inverse WT
  • IHT Inverse HT
  • IRT Inverse
  • Preferred shaping in FIG. 6 consists of an Mth order interpolation filter followed by an alias/window operation as shown in FIG. 10 a.
  • the Alias/window operation is described in FIG. 11a where a raised-cosine pulse of rolloff ⁇ is applied.
  • the interpolation filter in FIG. 10a can be implemented as an FIR filter or as an NM-point IDFT where the first N(M ⁇ 1)/2 points and the last N(M ⁇ 1)/2 points at the input of the IDFT are zero.
  • Preferred values of M are 1,2,3 and 4.
  • Preferred unshaping in FIG. 7 consists of a dealias/dewindow operation followed by a decimation filter as shown in FIG. 10 b.
  • the dealias/dewindow operation is described in FIG. 11 b.
  • Time Diversity in FIG. 6 can consist of repeating the MC-DSSS frame several times. It can also consist of repeating the frame several times then complex conjugating some of the replicas, or shifting some of the replicas in the frequency domain in a cyclic manner.
  • Diversity combining in FIG. 7 can consist of cophasing, selective combining, Maximal Ratio combining or equal gain combining.
  • L pilots are used to equalize the effects of the channel on each information-bearing data frame.
  • the pilot frames can consist of Data frames of known information symbols to be sent either before, during or after the data, or of a number of samples of known values inserted within two transformations in FIG. 4.
  • a preferred embodiment of the pilots is to have the first pilot consisting of a number of frames of known information symbols.
  • the remaining pilots can consist of a number of known information symbols between two transforms.
  • the L estimators can consist of averaging of the pilots followed by either a parametric estimation or a nonparametric one similar to the channel estimator in the patent: “Method and Apparatus for Multiple Access between Transceivers in Wireless Communications using OFDM Spread Spectrum” by M. Fattouche and H. Zaghloul, filed in the U.S. Pat Office in Mar. 31, 1992, Ser. No. 07/861,725.
  • FIG. 12 a preferred embodiment of a packet is illustrated in FIG. 12 : a Request frame 40 , an Address frame, an Ack. frame, a Pilot frame 36 and a number of Data frames 38 .
  • the Request frame is used (1) as a wake-up call for all the receivers in the band, (2) for frame synchronization and (3) for packet synchronization. It can consist of a DSSS signal using one PN code repeated a number of times and ending with the same PN code with a negative polarity.
  • FIGS. 13 and 14 illustrate the transmitter and the receiver for the Request frame respectively. In FIG.
  • the dot product operation can be implemented as a correlator with either hard or soft decision (or equivalently as a filter matched to the PN code followed by a sample/hold circuit).
  • the Request frame receiver is constantly generating a signal out of the correlator. When the signal is above a certain threshold using the level detector, (1) a wake-up call signal is conveyed to the portion of the receiver responsible for the Address frame and (2) the frames are synchronized to the wake-up call. The packet is then synchronized to the negative differential correlation between the last two PN codes in the Request frame using a decoder as shown in FIG. 14 .
  • the Address frame can consist of a CDMA signal where one out of a number of codes is used at a time.
  • the code consists of a number of chips that indicate the destination address, the source address and/or the number of Data frames.
  • FIGS. 15 and 16 illustrate the transmitter and the receiver for the Address frame respectively. Each receiver differentially detects the received Address frame, then correlates the outcome with it is own code. If the output of the correlator is above a certain threshold, the receiver instructs its transmitter to transmit an Ack. Otherwise, the receiver returns to its initial (idle) state.
  • the Ack. frame is a PN code reflecting the status of the receiver, i.e. whether it is busy or idle. When it is busy, Node A aborts its transmission and retries some time later. When it is idle, Node A proceeds with transmitting the Pilot frame and the Data frames.
  • FIGS. 17 and 18 illustrate the transmitter and the receiver for the Address frame respectively.
  • An extension to the MC-DSSS modulation technique consists of passband modulation where the packet is up-converted from baseband to RF in the transmitter and later down-converted from RF to baseband in the receiver.
  • Passband modulation can be implemented using IF sampling which consists of implementing quadrature modulation/demodulation in an intermediate Frequency between baseband and RF, digitally as shown in FIGS. 19 and 20 which illustrate the transmitter and the receiver respectively.
  • IF sampling trades complexity of the analog RF components (at either the transmitter, the receiver or both) with complexity of the digital components.
  • carrier feed-through is often a problem implying that the transmitter has to ensure a zero dc component. Such a component reduces the usable bandwidth of the channel. In IF sampling the usable band of the channel does not include dc and therefore is the dc component is not a concern.
  • a further extension to the MC-DSSS modulation technique consists of using antenna Diversity in order to improve the Signal-to-Ratio level at the receiver.
  • a preferred combining technique is maximal selection combining based on the level of the Request frame at the receiver.

Abstract

In this patent, we present MultiCode Direct Sequence Spread Spectrum (MC-DSSS) which is a modulation scheme that assigns up to N DSSS codes to an individual user where N is the number of chips per DSSS code. When viewed as DSSS, MC-DSSS requires up to N correlators (or equivalently up to N Matched Filters) at the receiver with a complexity of the order of N2 operations. In addition, a non ideal communication channel can cause InterCode Interference (ICI), i.e., interference between the N DSSS codes. In this patent, we introduce new DSSS codes, which we refer to as the “MC” codes. Such codes allow the information in a MC-DSSS signal to be decoded in a sequence of low complexity parallel operations which reduce the ICI. In addition to low complexity decoding and reduced ICI. MC-DSSS using the MC codes has the following advantages: (1) it does not require the stringent synchronization DSSS requires, (2) it does not require the stringent carrier recovery DSSS requires and (3) it is spectrally efficient.

Description

This application is a REISSUE of Ser. No. 08/186,784 filed Jan. 24, 1994 is a continuation-in-part of U.S. application Ser. No. 07/861,725 filed Mar. 31, 1992, now U.S. Pat. No. 5,282,222, the benefit of the filing date of which is hereby claimed under 35 U.S.C. §120.
FIELD OF THE INVENTION
The invention deals with the field of multiple access communications using Spread Spectrum modulation. Multiple access can be classified as either random access, polling, TDMA, FDMA, CDMA or any combination thereof. Spread Spectrum can be classified as Direct Sequence, Frequency-Hopping or a combination of the two.
BACKGROUND OF THE INVENTION
Commonly used spread spectrum techniques are Direct Sequence Spread Spectrum (DSSS) and Code Division Multiple Access (CDMA) as explained in Chapter 8 of “Digital Communication” by J. G. Proakis, Second Edition, 1991, McGraw Hill, DSSS is a communication scheme in which information bits are spread over code bits (generally called chips). It is customary to use noise-like codes called pseudo random noise (PN) sequences. These PN sequences have the property that their auto-correlation is almost a delta function and their cross-correlation with other codes is almost null. The advantages of this information spreading are:
1. The transmitted signal can be buried in noise and thus has a low probability of intercept.
2. The receiver can recover the signal from interferers (such as other transmitted codes) with a jamming margin that is proportional to the spreading code length.
3. DSSS codes of duration longer than the delay spread of the propagation channel can lead to multipath diversity implementable using a Rake receiver.
4. The FCC and the DOC have allowed the use of unlicensed low power DSSS systems of code lengths greater than or equal to 10 in some frequency bands (the ISM bands).
It is the last advantage (i.e., advantage 4. above) that has given much interest recently to DSSS.
An obvious limitation of DSSS systems is the limited throughput they can offer. In any given bandwidth, B, a code of length N will reduce the effective bandwidth to B/N. To increase the overall bandwidth efficiency, system designers introduced Code Division Multiple Access (CDMA) where multiple DSSS communication links can be established simultaneously over the same frequency band provided each link uses a unique code that is noise-like. CDMA problems are:
1. The near-far problem: a transmitter “near” the receiver sending a different code than the receiver's desired code produces in the receiver a signal comparable with that of a “far” transmitter sending the desired code.
2. Synchronization of the receiver and the transmitter is complex (especially) if the receiver does not know in advance which code is being transmitted.
SUMMARY OF THE INVENTION
We have recognized that low power DSSS systems complying with the FCC and the DOC regulations for the ISM bands would be ideal communicators provided the problems of CDMA could be resolved and the throughput could be enhanced. To enhance the throughput, we allow a single link (i.e., a single transceiver) to use more than one code at the same time. To avoid the near-far problem only one transceiver transmits at a time. In this patent, we present Multi-Code Direct Sequence Spread Spectrum (MC-DSSS) which is a modulation scheme that assigns up to N codes to an individual transceiver where N is the number of chips per DSSS code. When viewed as DSSS, MC-DSSS requires up to N correlators (or equivalently up to N Matched Filters) at the receiver with a complexity of the order of N2 operations. When N is large, this complexity is prohibitive. In addition, a nonideal communication channel can cause InterCode Interference (ICI), i.e., interference between the N DSSS codes at the receiver. In this patent, we introduce new codes, which we refer to as “MC” codes. Such codes allow the information in a MC-DSSS signal to be decoded in a sequence of low complexity parallel operations while reducing the ICI. In addition to low complexity decoding and ICI reduction, our implementation of MC-DSSS using the MC codes has the following advantages:
1. It does not require the stringent synchronization DSSS requires. Conventional DSSS systems requires synchronization to within a fraction of a chip whereas MC-DSSS using the MC codes requires synchronization to within two chips.
2. It does not require the stringent carrier recovery DSSS requires. Conventional DSSS requires the carrier at the receiver to be phase locked to the received signal whereas MC-DSSS using the MC codes does not require phase locking the carriers. Commercially available crystals have sufficient stability for MC-DSSS.
3. It is spectrally efficient.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic showing for the Baseband Transmitter for the xth MC-DSSS frame: d(k)=[d(1,x) d(2,x) . . . d(N,k)] where c(i)=[c(1,i) c(2,i)] is the ith code and Sym(k)=[sym(1,k) sym(N,k)] is the kth information-bearing vector containing N symbols.
FIG. 2 is a schematic showing a Baseband Receiver for the kth received MC-DSSS frame: d′(k)=[d′(1,k) d′(2,k) . . . d′(N,k)] where c(i)=[c(1,i) c(2,i) . . . c(N,i)] is the ith code, Sy{circumflex over (m)}(k)=[sy{circumflex over (m)}(1,k) sy{circumflex over (m)}(2,k) . . . sy{circumflex over (m)}(N,k)] is the estimate of the Kth information-bearing vector Sym(k) and
Figure USRE037802-20020723-C00001
FIG. 3 is a schematic showing of the ith MC code c(i)=[c(i,1) c(i,2) . . . c(i,NO) where i can take one of the N values: 1,2, . . . N corresponding to the position of the single ‘1’ at the input of the first N-point transform.
FIG. 4 is a schematic showing the alternate transmitter for the kth MC-DSSS frame: d(k)=[d(1,k), d(2,k) . . . d(N,k)] using the MC codes generated in FIG. 3 where Sym(k)=[Sym(1,k)Sym(2k) . . . Sym(N,k)] is the kth information-bearing vector contacting N symbols.
FIG. 5 is the alternate receiver for the kth received MC-DSSS frame d′(k)=[d′(1k)d′(2,K) . . .d′(N,k)] using MC codes generated in FIG. 3 where Sy{circumflex over (m)}(k)=[sy{circumflex over (m)}(1,k) sy{circumflex over (m)}(2k) . . . sy{circumflex over (m)}(N,k)] is the estimate of the information-bearing vetor Sym(k).
FIG. 6 is a schematic showing the Baseband Transmitter of the kth Data Frame X(k) where Sym(N)=[sym(1,k) sym(2,k) . . . sym(N,k)] is the kth information-bearing vector d(k)=[c(1,k) d(2,k) . . . d(N,k)] is the kth MC-DSSS frame v(k)=[v(1,k) v(2,k) . . . v((1+β)MN,k)], βε(0,1), M=1,2,3 . . . and X(k)=[x(1k) x(2,k)], Z=Z=1, 2, 3, . . . .
FIG. 7 is a schematic showing the Baseband Receiver for the kth received Data Frame X′(k) where Sy{circumflex over (m)}(N)=[sy{circumflex over (m)}(1,k)] sy{circumflex over (m)}(2,k) . . . sy{circumflex over (m)}(N,k)] is the estimate of the kth information-bearing vector d′(k)=[d′(1,k) d′(2k) . . . d′(N,k)] is the kth received MC-DSSS frame v′(k)=[v′(1,k) v(2k) . . . v′((1+β) MN,k)], Bε(0,1), M=1,2,3, . . . and X′(k)=[x′(1,k) x′(2,k) . . . r′(Z,k)], Z=1,2,3 . . . .
FIG. 8 is a schematic showing the Randomizer Transform (RT) where a (1) a (2) . . . a (N) are complex constants chosen randomly.
FIG. 9 is a schematic showing the Permutation Transform (PT).
FIG. 10 is a schematic showing (a) the shaping of a MC-DSSS frame and (b) the unshaping of a MC-DSSS frame where d(k)=[d(1,k) d(2,k) . . . d(N,k)] is the kth MC-DSSS frame g(k)=[g(1,k) g(2k) . . . g(MN,k)], M=1,2,3, . . . , v(k)=[v(1,k) v(2,k) . . . v((1+β) MN,k)], Bε(0,1) d′(k)=[d(1,k) d(2,k) . . . d(N,K)] is the kth received MC-DSSS frame g′(k)=[g′(1,k) g′(2,k) . . . g′(M′N,k)] and v′(k)=[v(1,k) v′(2,k) . . . v′((1+β) M′N,k)], M′=1,2,3, . . . .
FIG. 11 is a schematic showing (a) Description of the alias/window operation (b) Description of dealias/dewindow operation, where 1/T is the symbol rate.
FIG. 12 is a schematic showing the frame structure for data transmission from source (Node A) to destination (Node B).
FIG. 13 is a schematic showing the baseband transmitter for one request frame v where c=[c(1) c(2) . . . c(1)] is the DSSS code, v=[v(1) v(2) . . . v((1+β)MI)], βε(0,1), M=1,2, . . . and I is the length of the DSSS code.
FIG. 14 is a schematic showing the baseband receiver for the received request frame where c=[c(1) c(2) . . . c(1)] is the DSSS code for the request frame, d′=[d(1) d(2) . . . d(1)] is the received request frame, v′=[v′(1) v′((1+β) MI)], βε(0,1), M=1,2, . . . and l is the length of the DSSS code.
FIG. 15 is a schematic showing the baseband transmitter for one address frame where c=[c(1) c(2) . . . c(1)] is the CDMA code for the address frame, v=[v(1) v(2) . . . v(1+β) MI)], βε(0,1), M=1,2, . . . and l′ is the length of the CDMA code.
FIG. 16 is a schematic showing the baseband receiver the address where c=[c(1) c(2) . . . c(I′)] is the CDMA code for the address frame, d′=[d(1) d(2) . . . d(I)] is the received address frame, v′[v′(1) v′(2) . . . v′((1+β) MI′)], βε(0,1), M=1,2, . . . and I′ is the length of the CDMA code.
FIG. 17 is a schematic showing the baseband transmitter for Ack. Frame where c=[c(1) c(2) . . . c(I′)] is the DSSS code for the Ack. frame, v=[v(1) v(2) . . . v((I+β) MI′)] βε(0,1), M=1,2,3, . . . and I′ is the length of the DSSS code.
FIG. 18 is a schematic showing the baseband receiver for the ack. frame where c=[c(1) c(2) . . . c(I″)] is the DSSS code for the Ack. frame, d′=[d(1) d(2) . . . d′(I″)] is the received Ack. frame, v′=[v′(1) v(2) . . . v′(1+β) MI″)], βε(0,1), M=1,2, . . . and I″ is the length of the DSSS code.
FIG. 19 is a schematic showing the passband transmitter for a packet where fo is the IF frequency and fo+fc is the RF frequency.
FIG. 20 is a schematic showing the passband receiver for a packet where fo is the IF frequency and fo+fc is the RF frequency.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
FIG. 1 illustrates the transmitter of the MC-DSSS modulation technique generating the kth MC-DSSS frame bearing N symbols of information. The symbols can be either analog or digital.
A converter 10 converts a stream of data symbols into plural sets of N data symbols each. A computing means 12 operates on the plural sets of N data symbols to produce modulated data symbols corresponding to an invertible randomized spreading of the stream of data symbols. A combiner 14 combines the modulated data symbols for transmission. The computing means shown in FIG. 1 includes a source 16 of N direct sequence spread spectrum code symbols and a modulator 18 to modulate each ith data symbol from each set of N data symbols with the I code symbol from the N code symbol to generate N modulated data symbols, and thereby spread each I data symbol over a separate code symbol.
FIG. 2 illustrates the receiver of the MC-DSSS modulation techniques accepting the kth MC-DSSS frame and generating estimates for the corresponding N symbols of information. The dot product in FIG. 2 can be implemented as a correlator. The detector can make either hard decisions or soft decisions.
A sequence of modulated data symbols is received at 22 in which the sequence of modulated data symbols has been generated by the transmitter such as is shown in FIG. 1 or 4. A second computing means 24 operates on the sequence of modulated data symbols to produce an estimate of the second string of data symbols. The computing means 24 shown in FIG. 2 includes a correlator 26 for correlating each I modulated data symbol from the received sequence of modulated data symbols with the I code symbol from the set of N code symbols and a detector 28 for detecting an estimate of the data symbols from output of the correlator 26.
FIG. 3 illustrates the code generator of the MC codes. Any one of the P N-point transforms in FIG. 3 consists of a reversible transform to the extent of the available arithmetic precision. In other words, with finite precision arithmetic, the transforms are allowed to add a limited amount of irreversible error.
One can use the MC-DSSS transmitter in FIG. 1 and the MC-DSSS receiver in FIG. 2 together with the MC codes generated using the code generator in FIG. 3 in order to implement MC-DSSS using the MC codes.
An alternative transmitter to the one in FIG. 1 using the MC codes in FIG. 3 is shown in FIG. 4.
The alternative transmitter shown in FIG. 4 includes a transformer 20 for operating on each set of N data symbols to generate N modulated data symbols as output. A series of transforms are shown.
An alternative receiver to the one in FIG. 2 using the MC codes in FIG. 3 is shown in FIG. 5. L pilots are required in FIG. 5 for equalization.
Both transmitters in FIGS. 1 and 4 allow using shaper 30 in diversity module 32 shaping and time diversity of the MC-DSSS signal as shown in FIG. 6. We will refer to the MC-DSSS frame with shaping and time diversity as a Data frame.
Both receivers in FIGS. 2 and 5 allow diversity combining followed by the unshaping of the Data frame as shown in FIG. 7. A Synch. is required in FIG. 7 for frame synchronization.
In addition to the Data frames, we need to transmit (1) all of the L pilots used in FIG. 5 to estimate and equalize for the various types of channel distortions, (2) the Synch. signal used in FIG. 7 for frame synchronization, and (3) depending on the access technique employed, the source address, destination address and number of Data frames. We will refer to the combination of all transmitted frames as a packet.
PREFERRED EMBODIMENTS OF THE INVENTION
Examples of the N-point transforms in FIG. 3 are a Discrete Fourier Transform (DFT), a Fast Fourier Transform (FFT), a Walsh Transform (WT), a Hilbert Transform (HT), a Randomizer Transform (RT) as the one illustrated in FIG. 8, a Permutator Transform (PT) as the one illustrated in FIG. 9, an Inverse DFT (IDFT), an Inverse FFT (IFFT), an Inverse WT (IWT), an Inverse HT (IHT), an Inverse RT (IRT), an Inverse PT (IPT), and any other reversible transform. When L=2 with the first N-point transform being a DFT and the second being a RT, we have a system identical to the patent: “Method and Apparatus for Multiple Access between Transceivers in Wireless Communications using OFDM Spread Spectrum” by M. Fattouche and H. Zaghloul, filed in the U.S. Pat Office in Mar. 31, 1992, Ser. No. 07/861,725.
Preferred shaping in FIG. 6 consists of an Mth order interpolation filter followed by an alias/window operation as shown in FIG. 10a. The Alias/window operation is described in FIG. 11a where a raised-cosine pulse of rolloff β is applied. The interpolation filter in FIG. 10a can be implemented as an FIR filter or as an NM-point IDFT where the first N(M−1)/2 points and the last N(M−1)/2 points at the input of the IDFT are zero. Preferred values of M are 1,2,3 and 4.
Preferred unshaping in FIG. 7 consists of a dealias/dewindow operation followed by a decimation filter as shown in FIG. 10b. The dealias/dewindow operation is described in FIG. 11b.
Time Diversity in FIG. 6 can consist of repeating the MC-DSSS frame several times. It can also consist of repeating the frame several times then complex conjugating some of the replicas, or shifting some of the replicas in the frequency domain in a cyclic manner.
Diversity combining in FIG. 7 can consist of cophasing, selective combining, Maximal Ratio combining or equal gain combining.
In FIG. 5, L pilots are used to equalize the effects of the channel on each information-bearing data frame. The pilot frames can consist of Data frames of known information symbols to be sent either before, during or after the data, or of a number of samples of known values inserted within two transformations in FIG. 4. A preferred embodiment of the pilots is to have the first pilot consisting of a number of frames of known information symbols. The remaining pilots can consist of a number of known information symbols between two transforms. The L estimators can consist of averaging of the pilots followed by either a parametric estimation or a nonparametric one similar to the channel estimator in the patent: “Method and Apparatus for Multiple Access between Transceivers in Wireless Communications using OFDM Spread Spectrum” by M. Fattouche and H. Zaghloul, filed in the U.S. Pat Office in Mar. 31, 1992, Ser. No. 07/861,725.
When Node A intends to transmit information to Node B, a preferred embodiment of a packet is illustrated in FIG. 12: a Request frame 40, an Address frame, an Ack. frame, a Pilot frame 36 and a number of Data frames 38. The Request frame is used (1) as a wake-up call for all the receivers in the band, (2) for frame synchronization and (3) for packet synchronization. It can consist of a DSSS signal using one PN code repeated a number of times and ending with the same PN code with a negative polarity. FIGS. 13 and 14 illustrate the transmitter and the receiver for the Request frame respectively. In FIG. 14, the dot product operation can be implemented as a correlator with either hard or soft decision (or equivalently as a filter matched to the PN code followed by a sample/hold circuit). The Request frame receiver is constantly generating a signal out of the correlator. When the signal is above a certain threshold using the level detector, (1) a wake-up call signal is conveyed to the portion of the receiver responsible for the Address frame and (2) the frames are synchronized to the wake-up call. The packet is then synchronized to the negative differential correlation between the last two PN codes in the Request frame using a decoder as shown in FIG. 14.
The Address frame can consist of a CDMA signal where one out of a number of codes is used at a time. The code consists of a number of chips that indicate the destination address, the source address and/or the number of Data frames. FIGS. 15 and 16 illustrate the transmitter and the receiver for the Address frame respectively. Each receiver differentially detects the received Address frame, then correlates the outcome with it is own code. If the output of the correlator is above a certain threshold, the receiver instructs its transmitter to transmit an Ack. Otherwise, the receiver returns to its initial (idle) state.
The Ack. frame is a PN code reflecting the status of the receiver, i.e. whether it is busy or idle. When it is busy, Node A aborts its transmission and retries some time later. When it is idle, Node A proceeds with transmitting the Pilot frame and the Data frames. FIGS. 17 and 18 illustrate the transmitter and the receiver for the Address frame respectively.
An extension to the MC-DSSS modulation technique consists of passband modulation where the packet is up-converted from baseband to RF in the transmitter and later down-converted from RF to baseband in the receiver. Passband modulation can be implemented using IF sampling which consists of implementing quadrature modulation/demodulation in an intermediate Frequency between baseband and RF, digitally as shown in FIGS. 19 and 20 which illustrate the transmitter and the receiver respectively. IF sampling trades complexity of the analog RF components (at either the transmitter, the receiver or both) with complexity of the digital components. Furthermore, in passband systems carrier feed-through is often a problem implying that the transmitter has to ensure a zero dc component. Such a component reduces the usable bandwidth of the channel. In IF sampling the usable band of the channel does not include dc and therefore is the dc component is not a concern.
A further extension to the MC-DSSS modulation technique consists of using antenna Diversity in order to improve the Signal-to-Ratio level at the receiver. A preferred combining technique is maximal selection combining based on the level of the Request frame at the receiver.

Claims (40)

We claim:
1. A transceiver for transmitting a first stream of data symbols, the transceiver comprising:
a converter for converting the first stream of data symbols into plural sets of N data symbols each;
first computing means for operating on the plural sets of N data symbols to produce modulated data symbols corresponding to an invertible randomized spreading of the first stream of data symbols; and
means to combine the modulated data symbols for transmission.
2. The transceiver of claim 1 in which the first computing means includes comprises:
a source of N more than one and up to M direct sequence spread spectrum code symbols codes, where M is the number of chips per direct sequence spread spectrum code; and
a modulator to modulate each ith data symbol from each set of N data symbols with the ith a code symbol from the N code symbol up to M direct sequence spread spectrum codes to generate N modulated data symbols, and thereby spread each ith data symbol set of data symbols over a separate code symbol .
3. The transceiver of claim 2 in which the code symbols direct sequence spread spectrum codes are generated by operation of a non-trivial N point transform on a sequence of input signals.
4. The transceiver of claim 1 in which the first computing means includes comprises:
a transformer for operating on each set of N data symbols to generate N modulated data symbols as output, the N modulated data symbols corresponding to spreading of each ith data symbol over a separate code symbol selected from a set of more than one and up to M codes, where M is the number of chips per code; and
means to combine the modulated data symbols for transmission.
5. The transceiver of claim 4 in which the transformer effectively applies a first transform selected from the group comprising consisting of a Fourier transform and a Walsh transform to the N data symbols.
6. The transceiver of claim 5 in which the first transform is a Fourier transform and it is followed by a randomizing transform.
7. The transceiver of claim 6 in which the first transform is a Fourier transform and it is followed by a randomizing transform and a second transform selected from the group comprising consisting of a Fourier transform and a Walsh transform.
8. The transceiver of claim 4 in which the transformer effectively applies a first inverse transform selected from the group comprising consisting of a randomizer transform, a Fourier transform and a Walsh transform to the N data symbols, followed by a first equalizer and a second inverse transform selected from the group comprising consisting of a Fourier transform and a Walsh transform.
9. The transceiver of claim 8 in which the second transform is followed by a second equalizer.
10. The transceiver of claim 1 further including comprising:
means for receiving a sequence of modulated data symbols, the modulated data symbols having been generated by invertible randomized spreading of a second stream of data symbols; and
second computing means for operating on the sequence of modulated data symbols to produce an estimate of the second stream of data symbols.
11. The transceiver of claim 10 further including comprising means to apply diversity to the modulated data symbols before transmission, and means to combine received diversity signals.
12. The transceiver of claim 10 in which the second computing means includes comprises:
a correlator for correlating each ith modulated data symbol from the received sequence of modulated data symbols with the ith code symbol a code from the a set of N code symbols more than one and up to M codes, where M is the number of chips per code; and
a detector for detecting an estimate of the data symbols from output of the correlator.
13. The transceiver of claim 10 in which the second computing means includes comprises an inverse transformer for regenerating an estimate of the N data symbols.
14. The transceiver of claim 1 further including comprising a shaper for shaping the combined modulated data symbols for transmission.
15. The transceiver of claim 1 further including comprising means to apply diversity to the combined modulated data symbols before transmission.
16. The transceiver of claim 1 in which the N data symbols include a pilot frame and a number of data frames, and is preceded by a request frame, wherein the request frame is used to wake up receiving transceivers, synchronize reception of the N data symbols and convey protocol information.
17. A transceiver for transmitting a first stream of data symbols and receiving a second stream of data symbols, the transceiver comprising:
a converter for converting the first stream of data symbols into plural sets of N data symbols each;
first computing means for operating on the plural sets of N data symbols to produce sets of N modulated data symbols corresponding to an invertible randomized spreading of each set of N data symbols over N code symbols more than one and up to M direct sequence spread spectrum codes;
means to combine the modulated data symbols for transmission;
means for receiving a sequence of modulated data symbols, the modulated data symbols having been generated by an invertible randomized spreading of a second stream of data symbols over N code symbols more than one and up to M direct sequence spread spectrum codes;
second computing means for operating on the sequence of modulated data symbols to produce an estimate of the second stream of data symbols; and
means to combine output from the second computing means.
18. The transceiver of claim 17 in which the first computing means includes comprises:
a source of N the direct sequence spread spectrum code symbols codes; and
a modulator to modulate each ith data symbol from each set of N data symbols with the ith code symbol a code from the N code symbol up to M direct sequence spread spectrum codes to generate N modulated data symbols, and thereby spread each ith data symbol over a separate direct sequence spread spectrum code symbol .
19. The transceiver of claim 18 in which the code symbols direct sequence spread spectrum codes are generated by operation of plural non-trivial N point transforms on a random sequence of input signals.
20. The transceiver of claim 17 in which the first computing means includes comprises:
a transformer for operating on each set of N data symbols to generate N modulated data symbols as output, the N modulated data symbols corresponding to spreading of each ith data symbol over a separate code symbol .
21. The transceiver of claim 17 in which the second computing means includes comprises:
a correlator for correlating each ith modulated data symbol from the received sequence of modulated data symbols with the ith code symbol a code from the set of N code symbols up to M direct sequence spread spectrum codes; and
a detector for detecting an estimate of the data symbols from the output of the correlator.
22. The transceiver of claim 17 in which the second computing means includes comprises an inverse transformer for regenerating an estimate of the N data symbols.
23. A method of exchanging data streams between a plurality of transceivers, the method comprising the steps of:
converting a first stream of data symbols into plural sets of N data symbols each;
operating on the plural sets of N data symbols to produce modulated data symbols corresponding to a spreading of the first stream of data symbols over N code symbols more than one and up to M direct sequence spread spectrum codes;
combining the modulated data symbols for transmission; and
transmitting the modulated data symbols from a first transceiver at a time when no other of the plurality of transceivers is transmitting.
24. The method of claim 23 in which the spreading is an invertible randomized spreading and operating on the plural sets of N data symbols includes comprises modulating each ith data symbol from each set of N data symbols with the ith code symbol a code from the N code symbols up to M direct sequence spread spectrum codes to generate N modulated data symbols, and thereby spread each ith data symbol over a separate code symbol .
25. The method of claim 23 in which the spreading is an invertible randomized spreading and operating on the plural sets of N data symbols includes comprises:
transforming, by application of a transform, each set of N data symbols to generate N modulated data symbols as output.
26. The method of claim 25 in which transforming each set of N data symbols includes comprises applying to each set of N data symbols a randomizing transform and a transform selected from the group comprising consisting of a Fourier transform and a Walsh transform.
27. The method of claim 25 in which transforming each set of N data symbols includes comprises applying to each set of N data symbols a Fourier transform, a randomizing transform and a transform selected from the group comprising consisting of a Fourier transform and a Walsh transform.
28. The method of claim 25 in which transforming each set of N data symbols includes comprises applying to each set of N data symbols a first transform selected from the group comprising consisting of a Fourier transform and a Walsh transform, a randomizing transform and a second transform selected from the group comprising consisting of a Fourier transform and a Walsh transform.
29. The method of claim 23 further including comprising the step of:
receiving, at a transceiver distinct from the first transceiver, the sequence of modulated data symbols; and
operating on the sequence of modulated data symbols to produce an estimate of the first stream of data symbols.
30. The method of claim 29 in which operating on the sequence of modulated data symbols includes comprises the steps of:
correlating each ith modulated data symbol from the received sequence of modulated data symbols with the ith code symbol from the set of N code symbols a code from the up to M direct sequence spread spectrum codes; and
detecting an estimate of the first stream of data symbols from output of the correlator.
31. The method of claim 23 further including comprising the step of shaping the modulated data symbols before transmission.
32. The method of claim 23 further including comprising the step of applying diversity to the modulated data symbols before transmission.
33. A transceiver for transmitting a first stream of data symbols, the transceiver comprising:
a converter for converting the first stream of data symbols into plural sets of data symbols each;
first computing means for operating on the plural sets of data symbols to produce modulated data symbols corresponding to an invertible randomized spreading of the first stream of data symbols over more than one and up to M direct sequence spread spectrum codes, where each direct sequence spread spectrum code has M chips; and
means to combine the modulated data symbols for transmission.
34. The transceiver of claim 33 further comprising:
means for receiving a sequence of modulated data symbols, the modulated data symbols having been generated by invertible randomized spreading of a second stream of data symbols; and
second computing means for operating on the sequence of modulated data symbols to produce an estimate of the second stream of data symbols.
35. The transceiver of claim 34 further comprising means to apply diversity to the modulated data symbols before transmission, and means to combine received diversity signals.
36. The transceiver of claim 34 in which the second computing means comprises:
a correlator for correlating each modulated data symbol from the received sequence of modulated data symbols with a code from the set of up to M direct sequence spread spectrum codes; and
a detector for detecting an estimate of the data symbols from output of the correlator.
37. The transceiver of claim 34 in which the second computing means comprises an inverse transformer for regenerating an estimate of the data symbols.
38. The transceiver of claim 33 further comprising a shaper for shaping the combined modulated data symbols for transmission.
39. The transceiver of claim 33 further comprising means to apply diversity to the combined modulated data symbols before transmission.
40. The transceiver of claim 33 in which the data symbols include a pilot frame and a number of data frames, and is preceded by a request frame, wherein the request frame is used to wake up receiving transceivers, synchronize reception of the data symbols and convey protocol information.
US09/151,604 1992-03-31 1998-09-10 Multicode direct sequence spread spectrum Expired - Lifetime USRE37802E1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US07/861,725 US5282222A (en) 1992-03-31 1992-03-31 Method and apparatus for multiple access between transceivers in wireless communications using OFDM spread spectrum
US08/186,784 US5555268A (en) 1994-01-24 1994-01-24 Multicode direct sequence spread spectrum
US15160498A 1998-09-10 1998-09-10

Publications (1)

Publication Number Publication Date
USRE37802E1 true USRE37802E1 (en) 2002-07-23

Family

ID=57048653

Family Applications (1)

Application Number Title Priority Date Filing Date
US09/151,604 Expired - Lifetime USRE37802E1 (en) 1992-03-31 1998-09-10 Multicode direct sequence spread spectrum

Country Status (1)

Country Link
US (1) USRE37802E1 (en)

Cited By (67)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020188731A1 (en) * 2001-05-10 2002-12-12 Sergey Potekhin Control unit for multipoint multimedia/audio system
US20040233836A1 (en) * 2002-03-26 2004-11-25 Atsushi Sumasu Multi-carrier transmission apparatus and multi-carrier transmission method
US20050025079A1 (en) * 2003-07-18 2005-02-03 Shigeo Terabe Mobile communication system, radio control station, base station and mobile station for the system, and parameter determination method employing parallel combinatory spread-spectrum scheme
US20050047367A1 (en) * 2001-12-06 2005-03-03 Ismail Lakkis Ultra-wideband communication systems and methods
US20050078736A1 (en) * 2001-12-06 2005-04-14 Ismail Lakkis Ultra-wideband communication systems and methods
US20050117557A1 (en) * 2001-12-06 2005-06-02 Ismail Lakkis Ultra-wideband communication apparatus and methods
US20050152475A1 (en) * 2001-12-06 2005-07-14 Ismail Lakkis Systems and methods for receiving data in a wireless communication network
US20050157782A1 (en) * 2001-12-06 2005-07-21 Ismail Lakkis Systems and methods for transmitting data in a wireless communication network
US20050201473A1 (en) * 2001-12-06 2005-09-15 Ismail Lakkis Systems and methods for receiving data in a wireless communication network
US20050201326A1 (en) * 2001-12-06 2005-09-15 Lakkis Ismail A. Systems and methods for wireless communication over a wide bandwidth channel using a plurality of sub-channels
US20050213729A1 (en) * 2000-12-26 2005-09-29 Polycom,Inc. Speakerphone using a secure audio connection to initiate a second secure connection
US20050213734A1 (en) * 2001-12-31 2005-09-29 Polycom, Inc. Conference bridge which detects control information embedded in audio information to prioritize operations
US20050213735A1 (en) * 2000-12-26 2005-09-29 Polycom, Inc. Speakerphone transmitting URL information to a remote device
US20050213733A1 (en) * 2001-12-31 2005-09-29 Polycom, Inc. Speakerphone and conference bridge which receive and provide participant monitoring information
US20050213517A1 (en) * 2000-12-26 2005-09-29 Polycom, Inc. Conference endpoint controlling audio volume of a remote device
US20050213727A1 (en) * 2001-05-10 2005-09-29 Polycom, Inc. Speakerphone and conference bridge which request and perform polling operations
US20050213726A1 (en) * 2001-12-31 2005-09-29 Polycom, Inc. Conference bridge which transfers control information embedded in audio information between endpoints
US20050213736A1 (en) * 2001-12-31 2005-09-29 Polycom, Inc. Speakerphone establishing and using a second connection of graphics information
US20050213732A1 (en) * 2001-12-31 2005-09-29 Polycom, Inc. Conference bridge which decodes and responds to control information embedded in audio information
US20050213730A1 (en) * 2000-12-26 2005-09-29 Polycom, Inc. Conference endpoint instructing conference bridge to dial phone number
US20050213739A1 (en) * 2001-05-10 2005-09-29 Polycom, Inc. Conference endpoint controlling functions of a remote device
US20060072649A1 (en) * 2002-10-26 2006-04-06 Kyung-Hi Chang Frequency hopping ofdma method using symbols of comb pattern
US7031371B1 (en) 2000-09-25 2006-04-18 Lakkis Ismail A CDMA/TDMA communication method and apparatus for wireless communication using cyclic spreading codes
US20060109067A1 (en) * 2004-11-22 2006-05-25 Ruckus Wireless, Inc. Circuit board having a pereipheral antenna apparatus with selectable antenna elements and selectable phase shifting
US20060282184A1 (en) * 2005-06-08 2006-12-14 Polycom, Inc. Voice interference correction for mixed voice and spread spectrum data signaling
US20070047624A1 (en) * 2005-06-08 2007-03-01 Polycom, Inc Mixed voice and spread spectrum data signaling with enhanced concealment of data
US20070047626A1 (en) * 2005-06-08 2007-03-01 Polycom, Inc Mixed voice and spread spectrum data signaling with multiplexing multiple users with cdma
US7317756B2 (en) 2001-12-06 2008-01-08 Pulse-Link, Inc. Ultra-wideband communication apparatus and methods
US20080008275A1 (en) * 1997-09-16 2008-01-10 Cingular Wireless Ii, Llc Transmitter diversity technique for wireless communications
US7339955B2 (en) 2000-09-25 2008-03-04 Pulse-Link, Inc. TDMA communication method and apparatus using cyclic spreading codes
US20080084952A1 (en) * 2001-06-08 2008-04-10 Kolze Thomas J Channel equalization with scdma modulation
US20080143819A1 (en) * 2004-04-16 2008-06-19 Polycom, Inc. Conference link between a speakerphone and a video conference unit
US7433382B1 (en) * 2003-07-07 2008-10-07 Miao George J Spread spectrum based multichannel modulation for ultra wideband communications
US7498996B2 (en) 2004-08-18 2009-03-03 Ruckus Wireless, Inc. Antennas with polarization diversity
US7511680B2 (en) 2004-08-18 2009-03-31 Ruckus Wireless, Inc. Minimized antenna apparatus with selectable elements
US7525486B2 (en) 2004-11-22 2009-04-28 Ruckus Wireless, Inc. Increased wireless coverage patterns
US7627056B1 (en) * 2002-03-29 2009-12-01 Scientific Research Corporation System and method for orthogonally multiplexed signal transmission and reception on a non-contiguous spectral basis
US7639106B2 (en) 2006-04-28 2009-12-29 Ruckus Wireless, Inc. PIN diode network for multiband RF coupling
US7646343B2 (en) 2005-06-24 2010-01-12 Ruckus Wireless, Inc. Multiple-input multiple-output wireless antennas
US7652632B2 (en) 2004-08-18 2010-01-26 Ruckus Wireless, Inc. Multiband omnidirectional planar antenna apparatus with selectable elements
US7696946B2 (en) 2004-08-18 2010-04-13 Ruckus Wireless, Inc. Reducing stray capacitance in antenna element switching
US7880683B2 (en) 2004-08-18 2011-02-01 Ruckus Wireless, Inc. Antennas with polarization diversity
US7965252B2 (en) 2004-08-18 2011-06-21 Ruckus Wireless, Inc. Dual polarization antenna array with increased wireless coverage
US7978838B2 (en) 2001-12-31 2011-07-12 Polycom, Inc. Conference endpoint instructing conference bridge to mute participants
US8023458B2 (en) 2001-12-31 2011-09-20 Polycom, Inc. Method and apparatus for wideband conferencing
US8031129B2 (en) 2004-08-18 2011-10-04 Ruckus Wireless, Inc. Dual band dual polarization antenna array
US8045935B2 (en) 2001-12-06 2011-10-25 Pulse-Link, Inc. High data rate transmitter and receiver
US8068068B2 (en) 2005-06-24 2011-11-29 Ruckus Wireless, Inc. Coverage antenna apparatus with selectable horizontal and vertical polarization elements
US8217843B2 (en) 2009-03-13 2012-07-10 Ruckus Wireless, Inc. Adjustment of radiation patterns utilizing a position sensor
US8223942B2 (en) 2001-12-31 2012-07-17 Polycom, Inc. Conference endpoint requesting and receiving billing information from a conference bridge
US8351545B2 (en) 1997-10-31 2013-01-08 At&T Mobility Ii Llc Low complexity maximum likelihood detection of concatenated space codes for wireless applications
US8686905B2 (en) 2007-01-08 2014-04-01 Ruckus Wireless, Inc. Pattern shaping of RF emission patterns
US8698675B2 (en) 2009-05-12 2014-04-15 Ruckus Wireless, Inc. Mountable antenna elements for dual band antenna
US8705719B2 (en) 2001-12-31 2014-04-22 Polycom, Inc. Speakerphone and conference bridge which receive and provide participant monitoring information
US8756668B2 (en) 2012-02-09 2014-06-17 Ruckus Wireless, Inc. Dynamic PSK for hotspots
US8934381B2 (en) 2001-12-31 2015-01-13 Polycom, Inc. Conference endpoint instructing a remote device to establish a new connection
US8977683B2 (en) 2000-12-26 2015-03-10 Polycom, Inc. Speakerphone transmitting password information to a remote device
US9019165B2 (en) 2004-08-18 2015-04-28 Ruckus Wireless, Inc. Antenna with selectable elements for use in wireless communications
US9092610B2 (en) 2012-04-04 2015-07-28 Ruckus Wireless, Inc. Key assignment for a brand
US9106286B2 (en) 2000-06-13 2015-08-11 Comcast Cable Communications, Llc Network communication using diversity
US9407012B2 (en) 2010-09-21 2016-08-02 Ruckus Wireless, Inc. Antenna with dual polarization and mountable antenna elements
US9570799B2 (en) 2012-09-07 2017-02-14 Ruckus Wireless, Inc. Multiband monopole antenna apparatus with ground plane aperture
US9634403B2 (en) 2012-02-14 2017-04-25 Ruckus Wireless, Inc. Radio frequency emission pattern shaping
US10186750B2 (en) 2012-02-14 2019-01-22 Arris Enterprises Llc Radio frequency antenna array with spacing element
US10230161B2 (en) 2013-03-15 2019-03-12 Arris Enterprises Llc Low-band reflector for dual band directional antenna
US10545245B2 (en) * 2014-09-16 2020-01-28 Nottingham Scientific Limited GNSS jamming signal detection
US10720959B2 (en) * 2017-10-12 2020-07-21 British Cayman Islands Intelligo Technology Inc. Spread spectrum based audio frequency communication system

Citations (70)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3485949A (en) 1966-05-02 1969-12-23 Gen Dynamics Corp Differential phase shift keying receiver with information modulated on a plurality of tones
US3789149A (en) 1969-07-30 1974-01-29 Plessey Telecommunications Res Code division multiplex system
US3956619A (en) 1975-03-31 1976-05-11 General Electric Company Pipeline walsh-hadamard transformations
US3987374A (en) 1974-11-21 1976-10-19 International Business Machines Corporation Multi-line, multi-mode modulator using bandwidth reduction for digital FSK and DPSK modulation
US4092491A (en) 1977-04-04 1978-05-30 Bell Telephone Laboratories, Incorporated Differential encoding and decoding scheme for digital transmission systems
US4164628A (en) 1977-06-06 1979-08-14 International Telephone And Telegraph Corporation Processor for multiple, continuous, spread spectrum signals
US4306308A (en) 1979-09-14 1981-12-15 Rca Corporation Symbols communication system
US4457004A (en) 1982-02-08 1984-06-26 Bell Telephone Laboratories, Incorporated Multidimensional channel coding
GB2146875A (en) 1983-09-09 1985-04-24 Racal Res Ltd Communications systems
US4520490A (en) 1983-08-05 1985-05-28 At&T Information Systems Inc. Differentially nonlinear convolutional channel coding with expanded set of signalling alphabets
CA1203576A (en) 1977-08-22 1986-04-22 Josef Gammel Military radar - or radio communications transmission system
US4601045A (en) 1984-08-03 1986-07-15 Larse Corporation Modulator-demodulator method and apparatus with efficient bandwidth utilization
US4601005A (en) 1981-12-31 1986-07-15 The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland Receivers for navigation satellite systems
US4615040A (en) 1984-06-14 1986-09-30 Coenco Ltd. High speed data communications system
US4623980A (en) 1981-05-09 1986-11-18 Te Ka De Felten & Guilleaume Fernmeldeanlagen Gmbh Method of processing electrical signals by means of Fourier transformations
US4641318A (en) 1985-04-25 1987-02-03 Bell Communications Research, Inc. Method for improving the reliability of data transmission over Rayleigh fading channels
US4660215A (en) 1983-12-07 1987-04-21 Matsushita Electric Industrial Co., Ltd. Transmitter/receiver system
US4694466A (en) 1985-06-03 1987-09-15 Itt Defense Communications, A Division Of Itt Corporation Time sharing frequency synthesizer
US4713817A (en) 1985-04-25 1987-12-15 Codex Corporation Multidimensional, convolutionally coded communication systems
US4731816A (en) 1985-05-20 1988-03-15 Telebit Corporation Ensemble modem structure for imperfect transmission media
US4799214A (en) 1985-12-23 1989-01-17 Fujitsu Limited Two-wire full duplex frequency division multiplex modem system having echo cancellation means
US4809299A (en) 1987-05-05 1989-02-28 Ho Kit Fun Frequency independent information transmission system
US4829540A (en) 1986-05-27 1989-05-09 Fairchild Weston Systems, Inc. Secure communication system for multiple remote units
US4868874A (en) 1986-04-18 1989-09-19 Hitachi, Ltd. Echo canceller
US4881241A (en) 1988-02-24 1989-11-14 Centre National D'etudes Des Telecommunications Method and installation for digital communication, particularly between and toward moving vehicles
US4893266A (en) 1987-06-01 1990-01-09 Motorola, Inc. Alias tagging time domain to frequency domain signal converter
US4901307A (en) 1986-10-17 1990-02-13 Qualcomm, Inc. Spread spectrum multiple access communication system using satellite or terrestrial repeaters
US4914699A (en) 1988-10-11 1990-04-03 Itt Corporation High frequency anti-jam communication system terminal
US4928310A (en) * 1989-07-17 1990-05-22 Westinghouse Electric Corp. Pseudorandom pulse code generators using electro-optical XOR gates
US4933952A (en) * 1988-04-08 1990-06-12 Lmt Radioprofessionnelle Asynchronous digital correlator and demodulators including a correlator of this type
US4944009A (en) * 1988-02-25 1990-07-24 Massachusetts Institute Of Technology Pseudo-random sequence generator
US4979183A (en) 1989-03-23 1990-12-18 Echelon Systems Corporation Transceiver employing direct sequence spread spectrum techniques
US5029180A (en) 1989-03-23 1991-07-02 Echelon Systems Corporation Transceiver providing selectable frequencies and spreading sequences
US5034911A (en) 1988-04-11 1991-07-23 E-Systems, Inc. Signal parameterizer
US5063574A (en) 1990-03-06 1991-11-05 Moose Paul H Multi-frequency differentially encoded digital communication for high data rate transmission through unequalized channels
US5063560A (en) 1986-02-04 1991-11-05 Advanced Systems Research Pty. Limited Spread-spectrum multiplexed transmission system
US5073899A (en) 1988-07-13 1991-12-17 U.S. Philips Corporation Transmission system for sending two signals simultaneously on the same communications channel
US5089982A (en) 1990-05-24 1992-02-18 Grumman Aerospace Corporation Two dimensional fast Fourier transform converter
US5103459A (en) 1990-06-25 1992-04-07 Qualcomm Incorporated System and method for generating signal waveforms in a cdma cellular telephone system
US5128964A (en) 1990-10-10 1992-07-07 Intelligent Modem Corporation Modulation method and apparatus for multicarrier data transmission
US5134464A (en) 1990-11-16 1992-07-28 North American Philips Corporation Method and apparatus for the transmission and reception of a multicarrier digital television signal
US5151919A (en) 1990-12-17 1992-09-29 Ericsson-Ge Mobile Communications Holding Inc. Cdma subtractive demodulation
US5157686A (en) 1990-05-24 1992-10-20 Cylink Corporation Method and apparatus for the modulation of spread spectrum radio signals
US5166951A (en) 1991-05-15 1992-11-24 Scs Mobilecom, Inc. High capacity spread spectrum channel
US5193094A (en) 1990-03-07 1993-03-09 Qualcomm Incorporated Method and apparatus for generating super-orthogonal convolutional codes and the decoding thereof
US5210770A (en) 1991-09-27 1993-05-11 Lockheed Missiles & Space Company, Inc. Multiple-signal spread-spectrum transceiver
US5228025A (en) 1990-02-06 1993-07-13 Centre National D'etudes Des Telecommunications Method for the broadcasting of digital data, notably for radio broadcasting at a high bit-rate towards mobile receivers, with time-frequency interlacing and assistance in the acquisition of automatic frequency control, and corresponding receiver
US5235614A (en) * 1991-03-13 1993-08-10 Motorola, Inc. Method and apparatus for accommodating a variable number of communication channels in a spread spectrum communication system
EP0562868A2 (en) 1992-03-27 1993-09-29 WI-LAN Inc Method and apparatus for multiple access between transceivers in wireless communication using OFDM spread spectrum
EP0567771A2 (en) 1992-03-30 1993-11-03 Alcatel SEL Aktiengesellschaft Method, transmitter and receiver for the transmission of information with a variable traffic flow and a central station for the coordination of the different senders and receivers
US5268926A (en) 1991-09-11 1993-12-07 Societe Nationale D'etude Et De Construction De Moteurs D'aviation "S.N.E.C.M.A." Method and apparatus for the simultaneous transmission of separate data signals
US5274629A (en) 1990-02-06 1993-12-28 Etat Francais and Telediffusion de France SA Method for the broadcasting of digital data, notably for radio broadcasting at high bit rate towards mobile receivers, with time-frequency interlacing and coherent demodulation
US5278844A (en) * 1991-04-11 1994-01-11 Usa Digital Radio Method and apparatus for digital audio broadcasting and reception
US5285474A (en) 1992-06-12 1994-02-08 The Board Of Trustees Of The Leland Stanford, Junior University Method for equalizing a multicarrier signal in a multicarrier communication system
US5291515A (en) 1990-06-14 1994-03-01 Clarion Co., Ltd. Spread spectrum communication device
US5307376A (en) 1991-01-17 1994-04-26 France Telecom Device for the coherent demodulation of time-frequency interlaced digital data, with estimation of the frequency response of the transmission channel and threshold, and corresponsing transmitter
US5345440A (en) 1990-09-14 1994-09-06 National Transcommunications Limited Reception of orthogonal frequency division multiplexed signals
US5357541A (en) 1989-03-23 1994-10-18 Echelon Corporation Transceiver providing selectable frequencies and spreading sequences
US5375140A (en) 1992-11-24 1994-12-20 Stanford Telecommunications, Inc. Wireless direct sequence spread spectrum digital cellular telephone system
US5414734A (en) 1993-01-06 1995-05-09 Glenayre Electronics, Inc. Compensation for multi-path interference using pilot symbols
US5442625A (en) 1994-05-13 1995-08-15 At&T Ipm Corp Code division multiple access system providing variable data rate access to a user
US5467367A (en) 1991-06-07 1995-11-14 Canon Kabushiki Kaisha Spread spectrum communication apparatus and telephone exchange system
US5469469A (en) 1993-12-07 1995-11-21 University Of Massachusetts Lowell Research Foundation Composite spread spectrum signal including modulator demodulator
US5479447A (en) 1993-05-03 1995-12-26 The Board Of Trustees Of The Leland Stanford, Junior University Method and apparatus for adaptive, variable bandwidth, high-speed data transmission of a multicarrier signal over digital subscriber lines
US5487069A (en) 1992-11-27 1996-01-23 Commonwealth Scientific And Industrial Research Organization Wireless LAN
US5550812A (en) 1991-02-28 1996-08-27 U.S. Philips Corporation System for broadcasting and receiving digital data, receiver and transmitter for use in such system
US5596601A (en) 1994-08-30 1997-01-21 Lucent Technologies Inc. Method and apparatus for spread spectrum code pulse position modulation
US5615209A (en) 1995-07-26 1997-03-25 Ericsson Inc. Method and apparatus for CDMA signal orthogonalization
US5623511A (en) 1994-08-30 1997-04-22 Lucent Technologies Inc. Spread spectrum code pulse position modulated receiver having delay spread compensation
US5960032A (en) 1995-09-20 1999-09-28 The Hong Kong University Of Science & Technology High speed data transmission using expanded bit durations in multiple parallel coded data streams

Patent Citations (76)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3485949A (en) 1966-05-02 1969-12-23 Gen Dynamics Corp Differential phase shift keying receiver with information modulated on a plurality of tones
US3789149A (en) 1969-07-30 1974-01-29 Plessey Telecommunications Res Code division multiplex system
US3987374A (en) 1974-11-21 1976-10-19 International Business Machines Corporation Multi-line, multi-mode modulator using bandwidth reduction for digital FSK and DPSK modulation
US3956619A (en) 1975-03-31 1976-05-11 General Electric Company Pipeline walsh-hadamard transformations
US4092491A (en) 1977-04-04 1978-05-30 Bell Telephone Laboratories, Incorporated Differential encoding and decoding scheme for digital transmission systems
US4164628A (en) 1977-06-06 1979-08-14 International Telephone And Telegraph Corporation Processor for multiple, continuous, spread spectrum signals
CA1203576A (en) 1977-08-22 1986-04-22 Josef Gammel Military radar - or radio communications transmission system
US4306308A (en) 1979-09-14 1981-12-15 Rca Corporation Symbols communication system
US4623980A (en) 1981-05-09 1986-11-18 Te Ka De Felten & Guilleaume Fernmeldeanlagen Gmbh Method of processing electrical signals by means of Fourier transformations
US4601005A (en) 1981-12-31 1986-07-15 The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland Receivers for navigation satellite systems
US4457004A (en) 1982-02-08 1984-06-26 Bell Telephone Laboratories, Incorporated Multidimensional channel coding
US4520490A (en) 1983-08-05 1985-05-28 At&T Information Systems Inc. Differentially nonlinear convolutional channel coding with expanded set of signalling alphabets
GB2146875A (en) 1983-09-09 1985-04-24 Racal Res Ltd Communications systems
US4660215A (en) 1983-12-07 1987-04-21 Matsushita Electric Industrial Co., Ltd. Transmitter/receiver system
US4615040A (en) 1984-06-14 1986-09-30 Coenco Ltd. High speed data communications system
US4601045A (en) 1984-08-03 1986-07-15 Larse Corporation Modulator-demodulator method and apparatus with efficient bandwidth utilization
US4641318A (en) 1985-04-25 1987-02-03 Bell Communications Research, Inc. Method for improving the reliability of data transmission over Rayleigh fading channels
US4713817A (en) 1985-04-25 1987-12-15 Codex Corporation Multidimensional, convolutionally coded communication systems
US4731816A (en) 1985-05-20 1988-03-15 Telebit Corporation Ensemble modem structure for imperfect transmission media
US4694466A (en) 1985-06-03 1987-09-15 Itt Defense Communications, A Division Of Itt Corporation Time sharing frequency synthesizer
US4799214A (en) 1985-12-23 1989-01-17 Fujitsu Limited Two-wire full duplex frequency division multiplex modem system having echo cancellation means
US5063560A (en) 1986-02-04 1991-11-05 Advanced Systems Research Pty. Limited Spread-spectrum multiplexed transmission system
US4868874A (en) 1986-04-18 1989-09-19 Hitachi, Ltd. Echo canceller
US4829540A (en) 1986-05-27 1989-05-09 Fairchild Weston Systems, Inc. Secure communication system for multiple remote units
US4901307A (en) 1986-10-17 1990-02-13 Qualcomm, Inc. Spread spectrum multiple access communication system using satellite or terrestrial repeaters
US4809299A (en) 1987-05-05 1989-02-28 Ho Kit Fun Frequency independent information transmission system
US4893266A (en) 1987-06-01 1990-01-09 Motorola, Inc. Alias tagging time domain to frequency domain signal converter
US4881241A (en) 1988-02-24 1989-11-14 Centre National D'etudes Des Telecommunications Method and installation for digital communication, particularly between and toward moving vehicles
US4944009A (en) * 1988-02-25 1990-07-24 Massachusetts Institute Of Technology Pseudo-random sequence generator
US4933952A (en) * 1988-04-08 1990-06-12 Lmt Radioprofessionnelle Asynchronous digital correlator and demodulators including a correlator of this type
US5034911A (en) 1988-04-11 1991-07-23 E-Systems, Inc. Signal parameterizer
US5073899A (en) 1988-07-13 1991-12-17 U.S. Philips Corporation Transmission system for sending two signals simultaneously on the same communications channel
US4914699A (en) 1988-10-11 1990-04-03 Itt Corporation High frequency anti-jam communication system terminal
US5357541A (en) 1989-03-23 1994-10-18 Echelon Corporation Transceiver providing selectable frequencies and spreading sequences
US5029180A (en) 1989-03-23 1991-07-02 Echelon Systems Corporation Transceiver providing selectable frequencies and spreading sequences
US4979183A (en) 1989-03-23 1990-12-18 Echelon Systems Corporation Transceiver employing direct sequence spread spectrum techniques
US4928310A (en) * 1989-07-17 1990-05-22 Westinghouse Electric Corp. Pseudorandom pulse code generators using electro-optical XOR gates
US5274629A (en) 1990-02-06 1993-12-28 Etat Francais and Telediffusion de France SA Method for the broadcasting of digital data, notably for radio broadcasting at high bit rate towards mobile receivers, with time-frequency interlacing and coherent demodulation
US5228025A (en) 1990-02-06 1993-07-13 Centre National D'etudes Des Telecommunications Method for the broadcasting of digital data, notably for radio broadcasting at a high bit-rate towards mobile receivers, with time-frequency interlacing and assistance in the acquisition of automatic frequency control, and corresponding receiver
US5063574A (en) 1990-03-06 1991-11-05 Moose Paul H Multi-frequency differentially encoded digital communication for high data rate transmission through unequalized channels
US5166924A (en) 1990-03-06 1992-11-24 Mercury Digital Communications, Inc. Echo cancellation in multi-frequency differentially encoded digital communications
US5193094A (en) 1990-03-07 1993-03-09 Qualcomm Incorporated Method and apparatus for generating super-orthogonal convolutional codes and the decoding thereof
US5089982A (en) 1990-05-24 1992-02-18 Grumman Aerospace Corporation Two dimensional fast Fourier transform converter
US5157686A (en) 1990-05-24 1992-10-20 Cylink Corporation Method and apparatus for the modulation of spread spectrum radio signals
US5291515A (en) 1990-06-14 1994-03-01 Clarion Co., Ltd. Spread spectrum communication device
US5103459A (en) 1990-06-25 1992-04-07 Qualcomm Incorporated System and method for generating signal waveforms in a cdma cellular telephone system
US5715236A (en) 1990-06-25 1998-02-03 Qualcomm Incorporated System and method for generating signal waveforms in a CDMA cellular telephone system
US5309474A (en) 1990-06-25 1994-05-03 Qualcomm Incorporated System and method for generating signal waveforms in a CDMA cellular telephone system
US5416797A (en) 1990-06-25 1995-05-16 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
US5345440A (en) 1990-09-14 1994-09-06 National Transcommunications Limited Reception of orthogonal frequency division multiplexed signals
US5128964A (en) 1990-10-10 1992-07-07 Intelligent Modem Corporation Modulation method and apparatus for multicarrier data transmission
US5134464A (en) 1990-11-16 1992-07-28 North American Philips Corporation Method and apparatus for the transmission and reception of a multicarrier digital television signal
US5151919A (en) 1990-12-17 1992-09-29 Ericsson-Ge Mobile Communications Holding Inc. Cdma subtractive demodulation
US5307376A (en) 1991-01-17 1994-04-26 France Telecom Device for the coherent demodulation of time-frequency interlaced digital data, with estimation of the frequency response of the transmission channel and threshold, and corresponsing transmitter
US5550812A (en) 1991-02-28 1996-08-27 U.S. Philips Corporation System for broadcasting and receiving digital data, receiver and transmitter for use in such system
US5235614A (en) * 1991-03-13 1993-08-10 Motorola, Inc. Method and apparatus for accommodating a variable number of communication channels in a spread spectrum communication system
US5278844A (en) * 1991-04-11 1994-01-11 Usa Digital Radio Method and apparatus for digital audio broadcasting and reception
US5166951A (en) 1991-05-15 1992-11-24 Scs Mobilecom, Inc. High capacity spread spectrum channel
US5467367A (en) 1991-06-07 1995-11-14 Canon Kabushiki Kaisha Spread spectrum communication apparatus and telephone exchange system
US5268926A (en) 1991-09-11 1993-12-07 Societe Nationale D'etude Et De Construction De Moteurs D'aviation "S.N.E.C.M.A." Method and apparatus for the simultaneous transmission of separate data signals
US5210770A (en) 1991-09-27 1993-05-11 Lockheed Missiles & Space Company, Inc. Multiple-signal spread-spectrum transceiver
EP0562868A2 (en) 1992-03-27 1993-09-29 WI-LAN Inc Method and apparatus for multiple access between transceivers in wireless communication using OFDM spread spectrum
US5373502A (en) 1992-03-30 1994-12-13 Alcatel N.V. Process, transmitter and receiver for data transmission with variable traffic volume and a control station for coordinating several such transmitters and receivers
EP0567771A2 (en) 1992-03-30 1993-11-03 Alcatel SEL Aktiengesellschaft Method, transmitter and receiver for the transmission of information with a variable traffic flow and a central station for the coordination of the different senders and receivers
US5285474A (en) 1992-06-12 1994-02-08 The Board Of Trustees Of The Leland Stanford, Junior University Method for equalizing a multicarrier signal in a multicarrier communication system
US5375140A (en) 1992-11-24 1994-12-20 Stanford Telecommunications, Inc. Wireless direct sequence spread spectrum digital cellular telephone system
US5487069A (en) 1992-11-27 1996-01-23 Commonwealth Scientific And Industrial Research Organization Wireless LAN
US5414734A (en) 1993-01-06 1995-05-09 Glenayre Electronics, Inc. Compensation for multi-path interference using pilot symbols
US5479447A (en) 1993-05-03 1995-12-26 The Board Of Trustees Of The Leland Stanford, Junior University Method and apparatus for adaptive, variable bandwidth, high-speed data transmission of a multicarrier signal over digital subscriber lines
US5469469A (en) 1993-12-07 1995-11-21 University Of Massachusetts Lowell Research Foundation Composite spread spectrum signal including modulator demodulator
US5442625A (en) 1994-05-13 1995-08-15 At&T Ipm Corp Code division multiple access system providing variable data rate access to a user
US5596601A (en) 1994-08-30 1997-01-21 Lucent Technologies Inc. Method and apparatus for spread spectrum code pulse position modulation
US5623511A (en) 1994-08-30 1997-04-22 Lucent Technologies Inc. Spread spectrum code pulse position modulated receiver having delay spread compensation
US5615209A (en) 1995-07-26 1997-03-25 Ericsson Inc. Method and apparatus for CDMA signal orthogonalization
US5960032A (en) 1995-09-20 1999-09-28 The Hong Kong University Of Science & Technology High speed data transmission using expanded bit durations in multiple parallel coded data streams

Non-Patent Citations (32)

* Cited by examiner, † Cited by third party
Title
A 19.2 kbps Voiceband Data Modem Based on Orthogonally Multiplexed QAM Techniques, B. Hirosaki, A. Yoshida, O. Tanaka, S. Hasegawa, K. Inoue and K. Watanabe, CH2175-8/85/0000-0661 IEEE, pp. 661-665.
A Theoretical Study of Performance of an Orthogonal Multiplexing Data Transmission Scheme, Robert W. Chang and Richard A. Gibby, IEEE Transactions on Communication Technology, vol. Com.-16, No. 4, Aug. 1968, pp. 529-540.
Advanced Groupband Data Modem Using Orthogonally Multiplexed QAM Technique, Botaro Hirosaki, Satoshi Hasegawa and Akio Sabato, IEEE Transactions on Communications, vol. Com-34, No. 6, Jun. 1996, pp. 587-592.
Alard, M., et al., "A New System Of Sound Broadcasting To Mobile Receivers," pp. 416-420; 1988.
An Analysis of Automatic Equalizers of Orthogonally Multiplexed QAM Systems, Botaro Hirosaki, IEEE Transactions on Communications, vol. Com-28, No. 1, Jan. 1980, pp. 73-83.
An Improved Method for Digital SSB-FDM Modulation and Demodulation, Rikio Maruta and Atsushi Tomozawa, IEEE Transactions on Communications, vol. Com-26, No. 5, May 1978, pp. 720-725.
An Orthogonally Multiplexed QAM System Using the Discrete Fourier Transform, Botaro Hirosaki, IEEE Transactions on Communications, vol. Com-29, No. 7, Jul. 1981, pp. 982-989.
Analysis and Stimulation of a Digital Mobile Channel Using Orthogonal Frequency Division Multiplexing, Leonard J. Cimini, Jr., IEEE Transactions on Communications, vol. Comm-33, No. 7, Jul. 1985, pp. 665-675.
Ananasso, Fulvio, et al., "Clock Synchronous Multicarrier Demodulator For Multi-Frequency TDMA Communication Satellites," pp. 1059-1063; 1990.
Bingham, J.A.C.; "Multicarrier Modulation for Data Transmission: An Idea Whose Time Has Come", IEEE Communications Magazine, pp. 5-14, May 1990.
Chow, Jacky S., et al., "A Discrete Multitone Tranceiver System for HDSL Applications," pp. 895-908; "IEEE Journal on Selected Areas In Communications"; Aug. 1991.
Chow, Peter S., et al., "Performance Evaluation of a Multichannel Transceiver System for ADSL and VHDSL Services," pp. 909-919; IEEE Journal on Selected Areas in Communications; Aug. 1991.
Data Transmission by Frequency-Division Multiplexing Using the Discrete Fourier Transform, S.B. Weinstein and Paul M. Ebert, IEEE Transactions on Communications, vol. Com-19, No. 5, Oct. 1971, pp. 628-634.
Duch, Krzysztof M., "Baseband Signal Processing," Network Magazine, pp. 39-43; Nov. 1991.
Gledhill, J.J., et al., "The Transmission of Digital Television In The UHF Band Using Orthogonal Frequency Division Multiplexing," pp. 175-180, No Date.
Jinkang Zhu and Gen Marubayashi, Properties and Application of Parallel Combinatory SS Communication System, IEEE Second International Symposium on Spread Spectrum Techniques and Applications (ISSSTA '92), Yokohama, Japan, pp. 227-230, Nov. 29-Dec. 2, 1992.
Jinkang Zhu, Hongbin Zhang, Yucong Gu, Principle and Performance of Variable Rate Multi-code CDMA Method, 1995 Fourth IEEE International Conference on Universal Personal Communications. Record. Gateway to the 21st Century (Cat. No. 95TH8128). IEEE, pp. 256-259, New York, NY, USA, 1995.
K. Ben Letaief, J. C-I Chuang, and R.D. Murch, Multicode High-Speed Transmission for Wireless Mobile Communications, Proceedings of the 1995 IEEE Global Telecommunications Conference GLOBEOM'95, Singapore, pp. 1835-1839, Nov. 14-16, 1995.
OFDM for Data Communication over Mobile Radio FM Channels; Part I: Analysis and Experimental Results, E.F. Casas and C. Leung, IEEE Transactions on Communications, vol. 39, No. 5, May 1991.
OFDM for Data Communication over Mobile Radio FM Radio Channels; Part II: Performance Improvement, E.F. Casas and C. Leung, Dept. of Electrical Engineering, University of British Columbia, Vancouver, BC, Canada, 1991.
Optimized Decision Feedback Equalization Versus Optimized Orthogonal Frequency Division Multiplexing for High-Speed Data Transmission Over the Local Cable Network, Nikolaos A. Zervos and Irving Kalet, CH2655-9/89/0000-1989 IEEE, pp. 1080-1085.
Performance of an Efficient Parallel Data Transmission System, Burton R. Saltzberg, IEEE Transactions on Communication Technology, vol. Com-15, No. 6, Dec. 1967, pp. 805-811.
Performance of an RCPC-Coded OFDM-Based Digital Audio Broadcasting (DAB) System, P. Hoeher, J. Hagenauer, E. Offer, Ch. Rapp, H. Schulze, Globecom '91, CH 2980-1/91/0000-0040, pp. 0040-0046.
Proakis, J.G., Digital Communication, 2d ed., 1991, Chap. 8, "Spread Spectrum Signals for Digital Communications," pp. 800-891.
Pupolin, Silvano, et al., "Performance Analysis Of Digital Radio Links With Nonlinear Transmit Amplifier And Data Predistorter With Memory," pp. 9.6.1-9.6.5; 1989.
Reduction of Multipath Fading Effects in Single Variable Modulations, M.A. Poletti and R.G. Vaughan, ISSPA 90 Signal Processing Theories, Implementations and Applications, Gold Coast, Australia Aug. 27-31, 1990, 672-676.
Saito, Masafumi, et al., "A Digital Modulation Method For Terrestrial Digital TV Broadcasting Using Trellis Coded OFDM And Its Performance," pp. 1694-1698; Globecom '92 Conference; 1992.
Scott L. Miller and Weerakhan Tantiphaiboontana, Code Division Multiplexing-Efficient Modulation for High Data Rate Transmission Over Wireless Channels, Proceedings of 2000 IEEE International Conference on Communications, pp. 1487-1491.
Shigenobu Sasaki, Jinkang Zhu, and Gen Marubayashi, Performance of Parallel Combinatory Spread Spectrum Multiple Access Communication Systems, Proceedings of 1991 IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), pp. 204-208.
Spracklen, C.T. and C. Smythe, "The Application of Code Division Multiplexing Techniques to Local Area Networks," pp. 767-770, May 1987.
Synthesis of Band-Limited Orthogonal Signals for Multichannel Data Transmission, Robert W. Chang, The Bell System Technical Journal, Dec. 1966, pp. 1775-1796.
The Multitone Channel, Irving Kalet, IEEE Transactions on Communications, vol. 37, No. 2, Feb. 1989.

Cited By (136)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7916806B2 (en) * 1997-09-16 2011-03-29 At&T Mobility Ii Llc Transmitter diversity technique for wireless communications
US9203499B2 (en) 1997-09-16 2015-12-01 At&T Mobility Ii Llc Transmitter diversity technique for wireless communications
US9749032B2 (en) 1997-09-16 2017-08-29 At&T Mobility Ii Llc Transmitter diversity technique for wireless communications
US8355475B2 (en) 1997-09-16 2013-01-15 At&T Mobility Ii Llc Diversity technique for wireless communications
US20080008275A1 (en) * 1997-09-16 2008-01-10 Cingular Wireless Ii, Llc Transmitter diversity technique for wireless communications
US20110170635A1 (en) * 1997-09-16 2011-07-14 Siavash Alamouti Transmitter diversity technique for wireless communications
US9065516B2 (en) 1997-10-31 2015-06-23 At&T Mobility Ii, Llc Low complexity maximum likelihood detection of concatenated space codes for wireless applications
US8731107B2 (en) 1997-10-31 2014-05-20 At&T Mobility Ii Llc Low complexity maximum likelihood detection of concatenated space codes for wireless applications
US8351545B2 (en) 1997-10-31 2013-01-08 At&T Mobility Ii Llc Low complexity maximum likelihood detection of concatenated space codes for wireless applications
US9654323B2 (en) 2000-06-13 2017-05-16 Comcast Cable Communications, Llc Data routing for OFDM transmission based on observed node capacities
US9197297B2 (en) 2000-06-13 2015-11-24 Comcast Cable Communications, Llc Network communication using diversity
US9356666B1 (en) 2000-06-13 2016-05-31 Comcast Cable Communications, Llc Originator and recipient based transmissions in wireless communications
US9401783B1 (en) 2000-06-13 2016-07-26 Comcast Cable Communications, Llc Transmission of data to multiple nodes
US9344233B2 (en) 2000-06-13 2016-05-17 Comcast Cable Communications, Llc Originator and recipient based transmissions in wireless communications
US9515788B2 (en) 2000-06-13 2016-12-06 Comcast Cable Communications, Llc Originator and recipient based transmissions in wireless communications
US9722842B2 (en) 2000-06-13 2017-08-01 Comcast Cable Communications, Llc Transmission of data using a plurality of radio frequency channels
US9209871B2 (en) 2000-06-13 2015-12-08 Comcast Cable Communications, Llc Network communication using diversity
US9820209B1 (en) 2000-06-13 2017-11-14 Comcast Cable Communications, Llc Data routing for OFDM transmissions
US9391745B2 (en) 2000-06-13 2016-07-12 Comcast Cable Communications, Llc Multi-user transmissions
US10257765B2 (en) 2000-06-13 2019-04-09 Comcast Cable Communications, Llc Transmission of OFDM symbols
US10349332B2 (en) 2000-06-13 2019-07-09 Comcast Cable Communications, Llc Network communication using selected resources
USRE45807E1 (en) 2000-06-13 2015-11-17 Comcast Cable Communications, Llc Apparatus for transmitting a signal including transmit data to a multiple-input capable node
US9106286B2 (en) 2000-06-13 2015-08-11 Comcast Cable Communications, Llc Network communication using diversity
USRE45775E1 (en) 2000-06-13 2015-10-20 Comcast Cable Communications, Llc Method and system for robust, secure, and high-efficiency voice and packet transmission over ad-hoc, mesh, and MIMO communication networks
US7031371B1 (en) 2000-09-25 2006-04-18 Lakkis Ismail A CDMA/TDMA communication method and apparatus for wireless communication using cyclic spreading codes
US7339955B2 (en) 2000-09-25 2008-03-04 Pulse-Link, Inc. TDMA communication method and apparatus using cyclic spreading codes
US8948059B2 (en) 2000-12-26 2015-02-03 Polycom, Inc. Conference endpoint controlling audio volume of a remote device
US20050213517A1 (en) * 2000-12-26 2005-09-29 Polycom, Inc. Conference endpoint controlling audio volume of a remote device
US8977683B2 (en) 2000-12-26 2015-03-10 Polycom, Inc. Speakerphone transmitting password information to a remote device
US8964604B2 (en) 2000-12-26 2015-02-24 Polycom, Inc. Conference endpoint instructing conference bridge to dial phone number
US7864938B2 (en) 2000-12-26 2011-01-04 Polycom, Inc. Speakerphone transmitting URL information to a remote device
US9001702B2 (en) 2000-12-26 2015-04-07 Polycom, Inc. Speakerphone using a secure audio connection to initiate a second secure connection
US20050213729A1 (en) * 2000-12-26 2005-09-29 Polycom,Inc. Speakerphone using a secure audio connection to initiate a second secure connection
US20050213735A1 (en) * 2000-12-26 2005-09-29 Polycom, Inc. Speakerphone transmitting URL information to a remote device
US20050213730A1 (en) * 2000-12-26 2005-09-29 Polycom, Inc. Conference endpoint instructing conference bridge to dial phone number
US8805928B2 (en) 2001-05-10 2014-08-12 Polycom, Inc. Control unit for multipoint multimedia/audio system
US20020188731A1 (en) * 2001-05-10 2002-12-12 Sergey Potekhin Control unit for multipoint multimedia/audio system
US20050213727A1 (en) * 2001-05-10 2005-09-29 Polycom, Inc. Speakerphone and conference bridge which request and perform polling operations
US8976712B2 (en) 2001-05-10 2015-03-10 Polycom, Inc. Speakerphone and conference bridge which request and perform polling operations
US8934382B2 (en) 2001-05-10 2015-01-13 Polycom, Inc. Conference endpoint controlling functions of a remote device
US20050213739A1 (en) * 2001-05-10 2005-09-29 Polycom, Inc. Conference endpoint controlling functions of a remote device
US20080084952A1 (en) * 2001-06-08 2008-04-10 Kolze Thomas J Channel equalization with scdma modulation
US8254500B2 (en) * 2001-06-08 2012-08-28 Broadcom Corporation Channel equalization with SCDMA modulation
US7349439B2 (en) 2001-12-06 2008-03-25 Pulse-Link, Inc. Ultra-wideband communication systems and methods
US8045935B2 (en) 2001-12-06 2011-10-25 Pulse-Link, Inc. High data rate transmitter and receiver
US20050047367A1 (en) * 2001-12-06 2005-03-03 Ismail Lakkis Ultra-wideband communication systems and methods
US20050078736A1 (en) * 2001-12-06 2005-04-14 Ismail Lakkis Ultra-wideband communication systems and methods
US20050117557A1 (en) * 2001-12-06 2005-06-02 Ismail Lakkis Ultra-wideband communication apparatus and methods
US20050152475A1 (en) * 2001-12-06 2005-07-14 Ismail Lakkis Systems and methods for receiving data in a wireless communication network
US20050157782A1 (en) * 2001-12-06 2005-07-21 Ismail Lakkis Systems and methods for transmitting data in a wireless communication network
US20050201473A1 (en) * 2001-12-06 2005-09-15 Ismail Lakkis Systems and methods for receiving data in a wireless communication network
US20050201326A1 (en) * 2001-12-06 2005-09-15 Lakkis Ismail A. Systems and methods for wireless communication over a wide bandwidth channel using a plurality of sub-channels
US7289494B2 (en) 2001-12-06 2007-10-30 Pulse-Link, Inc. Systems and methods for wireless communication over a wide bandwidth channel using a plurality of sub-channels
US7317756B2 (en) 2001-12-06 2008-01-08 Pulse-Link, Inc. Ultra-wideband communication apparatus and methods
US7349478B2 (en) 2001-12-06 2008-03-25 Pulse-Link, Inc. Ultra-wideband communication apparatus and methods
US7352806B2 (en) 2001-12-06 2008-04-01 Tensorcom, Inc. Systems and methods for transmitting data in a wireless communication network
US8744389B2 (en) 2001-12-06 2014-06-03 Intellectual Ventures Holding 73 Llc High data rate transmitter and receiver
US7929596B2 (en) 2001-12-06 2011-04-19 Pulse-Link, Inc. Ultra-wideband communication apparatus and methods
US8532586B2 (en) 2001-12-06 2013-09-10 Intellectual Ventures Holding 73 Llc High data rate transmitter and receiver
US8934381B2 (en) 2001-12-31 2015-01-13 Polycom, Inc. Conference endpoint instructing a remote device to establish a new connection
US8223942B2 (en) 2001-12-31 2012-07-17 Polycom, Inc. Conference endpoint requesting and receiving billing information from a conference bridge
US8705719B2 (en) 2001-12-31 2014-04-22 Polycom, Inc. Speakerphone and conference bridge which receive and provide participant monitoring information
US7787605B2 (en) 2001-12-31 2010-08-31 Polycom, Inc. Conference bridge which decodes and responds to control information embedded in audio information
US8023458B2 (en) 2001-12-31 2011-09-20 Polycom, Inc. Method and apparatus for wideband conferencing
US7742588B2 (en) 2001-12-31 2010-06-22 Polycom, Inc. Speakerphone establishing and using a second connection of graphics information
US7978838B2 (en) 2001-12-31 2011-07-12 Polycom, Inc. Conference endpoint instructing conference bridge to mute participants
US20050213734A1 (en) * 2001-12-31 2005-09-29 Polycom, Inc. Conference bridge which detects control information embedded in audio information to prioritize operations
US8102984B2 (en) 2001-12-31 2012-01-24 Polycom Inc. Speakerphone and conference bridge which receive and provide participant monitoring information
US20050213733A1 (en) * 2001-12-31 2005-09-29 Polycom, Inc. Speakerphone and conference bridge which receive and provide participant monitoring information
US8144854B2 (en) 2001-12-31 2012-03-27 Polycom Inc. Conference bridge which detects control information embedded in audio information to prioritize operations
US8582520B2 (en) 2001-12-31 2013-11-12 Polycom, Inc. Method and apparatus for wideband conferencing
US20050213732A1 (en) * 2001-12-31 2005-09-29 Polycom, Inc. Conference bridge which decodes and responds to control information embedded in audio information
US20050213736A1 (en) * 2001-12-31 2005-09-29 Polycom, Inc. Speakerphone establishing and using a second connection of graphics information
US20050213726A1 (en) * 2001-12-31 2005-09-29 Polycom, Inc. Conference bridge which transfers control information embedded in audio information between endpoints
US20040233836A1 (en) * 2002-03-26 2004-11-25 Atsushi Sumasu Multi-carrier transmission apparatus and multi-carrier transmission method
US20090316568A1 (en) * 2002-03-29 2009-12-24 Harris Fredric J System and method for orthogonally multiplexed signal transmission and reception on a non-contiguous spectral basis
US7627056B1 (en) * 2002-03-29 2009-12-01 Scientific Research Corporation System and method for orthogonally multiplexed signal transmission and reception on a non-contiguous spectral basis
US7542504B2 (en) * 2002-10-26 2009-06-02 Electronics And Telecommunications Research Institute Frequency hopping ofdma method using symbols of comb pattern
US20060072649A1 (en) * 2002-10-26 2006-04-06 Kyung-Hi Chang Frequency hopping ofdma method using symbols of comb pattern
US7433382B1 (en) * 2003-07-07 2008-10-07 Miao George J Spread spectrum based multichannel modulation for ultra wideband communications
US20050025079A1 (en) * 2003-07-18 2005-02-03 Shigeo Terabe Mobile communication system, radio control station, base station and mobile station for the system, and parameter determination method employing parallel combinatory spread-spectrum scheme
US7292526B2 (en) * 2003-07-18 2007-11-06 Kabushiki Kaisha Toshiba Mobile communication system, radio control station, base station and mobile station for the system, and parameter determination method employing parallel combinatory spread-spectrum scheme
US8000340B2 (en) 2003-07-18 2011-08-16 Kabushiki Kaishatoshiba Parameter determination base station employing PCSS scheme
US20070268851A1 (en) * 2003-07-18 2007-11-22 Kabushiki Kaisha Toshiba Mobile communication system, radio control station, base station and mobile station for the system, and parameter determination method employing parallel combinatory spread-spectrum scheme
US8004556B2 (en) 2004-04-16 2011-08-23 Polycom, Inc. Conference link between a speakerphone and a video conference unit
US20080143819A1 (en) * 2004-04-16 2008-06-19 Polycom, Inc. Conference link between a speakerphone and a video conference unit
US8860629B2 (en) 2004-08-18 2014-10-14 Ruckus Wireless, Inc. Dual band dual polarization antenna array
US9077071B2 (en) 2004-08-18 2015-07-07 Ruckus Wireless, Inc. Antenna with polarization diversity
US7652632B2 (en) 2004-08-18 2010-01-26 Ruckus Wireless, Inc. Multiband omnidirectional planar antenna apparatus with selectable elements
US7696946B2 (en) 2004-08-18 2010-04-13 Ruckus Wireless, Inc. Reducing stray capacitance in antenna element switching
US8031129B2 (en) 2004-08-18 2011-10-04 Ruckus Wireless, Inc. Dual band dual polarization antenna array
US8314749B2 (en) 2004-08-18 2012-11-20 Ruckus Wireless, Inc. Dual band dual polarization antenna array
US7498996B2 (en) 2004-08-18 2009-03-03 Ruckus Wireless, Inc. Antennas with polarization diversity
US10181655B2 (en) 2004-08-18 2019-01-15 Arris Enterprises Llc Antenna with polarization diversity
US7965252B2 (en) 2004-08-18 2011-06-21 Ruckus Wireless, Inc. Dual polarization antenna array with increased wireless coverage
US7511680B2 (en) 2004-08-18 2009-03-31 Ruckus Wireless, Inc. Minimized antenna apparatus with selectable elements
US7880683B2 (en) 2004-08-18 2011-02-01 Ruckus Wireless, Inc. Antennas with polarization diversity
US9019165B2 (en) 2004-08-18 2015-04-28 Ruckus Wireless, Inc. Antenna with selectable elements for use in wireless communications
US9837711B2 (en) 2004-08-18 2017-12-05 Ruckus Wireless, Inc. Antenna with selectable elements for use in wireless communications
US20060109067A1 (en) * 2004-11-22 2006-05-25 Ruckus Wireless, Inc. Circuit board having a pereipheral antenna apparatus with selectable antenna elements and selectable phase shifting
US7525486B2 (en) 2004-11-22 2009-04-28 Ruckus Wireless, Inc. Increased wireless coverage patterns
US9379456B2 (en) 2004-11-22 2016-06-28 Ruckus Wireless, Inc. Antenna array
US7498999B2 (en) 2004-11-22 2009-03-03 Ruckus Wireless, Inc. Circuit board having a peripheral antenna apparatus with selectable antenna elements and selectable phase shifting
US9093758B2 (en) 2004-12-09 2015-07-28 Ruckus Wireless, Inc. Coverage antenna apparatus with selectable horizontal and vertical polarization elements
US10056693B2 (en) 2005-01-21 2018-08-21 Ruckus Wireless, Inc. Pattern shaping of RF emission patterns
US9270029B2 (en) 2005-01-21 2016-02-23 Ruckus Wireless, Inc. Pattern shaping of RF emission patterns
US8199791B2 (en) 2005-06-08 2012-06-12 Polycom, Inc. Mixed voice and spread spectrum data signaling with enhanced concealment of data
US7796565B2 (en) * 2005-06-08 2010-09-14 Polycom, Inc. Mixed voice and spread spectrum data signaling with multiplexing multiple users with CDMA
US20070047624A1 (en) * 2005-06-08 2007-03-01 Polycom, Inc Mixed voice and spread spectrum data signaling with enhanced concealment of data
US8126029B2 (en) 2005-06-08 2012-02-28 Polycom, Inc. Voice interference correction for mixed voice and spread spectrum data signaling
US20070047626A1 (en) * 2005-06-08 2007-03-01 Polycom, Inc Mixed voice and spread spectrum data signaling with multiplexing multiple users with cdma
US20060282184A1 (en) * 2005-06-08 2006-12-14 Polycom, Inc. Voice interference correction for mixed voice and spread spectrum data signaling
US8704720B2 (en) 2005-06-24 2014-04-22 Ruckus Wireless, Inc. Coverage antenna apparatus with selectable horizontal and vertical polarization elements
US8068068B2 (en) 2005-06-24 2011-11-29 Ruckus Wireless, Inc. Coverage antenna apparatus with selectable horizontal and vertical polarization elements
US9577346B2 (en) 2005-06-24 2017-02-21 Ruckus Wireless, Inc. Vertical multiple-input multiple-output wireless antennas
US7646343B2 (en) 2005-06-24 2010-01-12 Ruckus Wireless, Inc. Multiple-input multiple-output wireless antennas
US7675474B2 (en) 2005-06-24 2010-03-09 Ruckus Wireless, Inc. Horizontal multiple-input multiple-output wireless antennas
US8836606B2 (en) 2005-06-24 2014-09-16 Ruckus Wireless, Inc. Coverage antenna apparatus with selectable horizontal and vertical polarization elements
US7639106B2 (en) 2006-04-28 2009-12-29 Ruckus Wireless, Inc. PIN diode network for multiband RF coupling
US8686905B2 (en) 2007-01-08 2014-04-01 Ruckus Wireless, Inc. Pattern shaping of RF emission patterns
US8723741B2 (en) 2009-03-13 2014-05-13 Ruckus Wireless, Inc. Adjustment of radiation patterns utilizing a position sensor
US8217843B2 (en) 2009-03-13 2012-07-10 Ruckus Wireless, Inc. Adjustment of radiation patterns utilizing a position sensor
US9419344B2 (en) 2009-05-12 2016-08-16 Ruckus Wireless, Inc. Mountable antenna elements for dual band antenna
US8698675B2 (en) 2009-05-12 2014-04-15 Ruckus Wireless, Inc. Mountable antenna elements for dual band antenna
US10224621B2 (en) 2009-05-12 2019-03-05 Arris Enterprises Llc Mountable antenna elements for dual band antenna
US9407012B2 (en) 2010-09-21 2016-08-02 Ruckus Wireless, Inc. Antenna with dual polarization and mountable antenna elements
US9226146B2 (en) 2012-02-09 2015-12-29 Ruckus Wireless, Inc. Dynamic PSK for hotspots
US8756668B2 (en) 2012-02-09 2014-06-17 Ruckus Wireless, Inc. Dynamic PSK for hotspots
US10186750B2 (en) 2012-02-14 2019-01-22 Arris Enterprises Llc Radio frequency antenna array with spacing element
US9634403B2 (en) 2012-02-14 2017-04-25 Ruckus Wireless, Inc. Radio frequency emission pattern shaping
US10734737B2 (en) 2012-02-14 2020-08-04 Arris Enterprises Llc Radio frequency emission pattern shaping
US9092610B2 (en) 2012-04-04 2015-07-28 Ruckus Wireless, Inc. Key assignment for a brand
US9570799B2 (en) 2012-09-07 2017-02-14 Ruckus Wireless, Inc. Multiband monopole antenna apparatus with ground plane aperture
US10230161B2 (en) 2013-03-15 2019-03-12 Arris Enterprises Llc Low-band reflector for dual band directional antenna
US10545245B2 (en) * 2014-09-16 2020-01-28 Nottingham Scientific Limited GNSS jamming signal detection
US10720959B2 (en) * 2017-10-12 2020-07-21 British Cayman Islands Intelligo Technology Inc. Spread spectrum based audio frequency communication system

Similar Documents

Publication Publication Date Title
USRE37802E1 (en) Multicode direct sequence spread spectrum
US5555268A (en) Multicode direct sequence spread spectrum
US5729570A (en) Orthogonal code division multiple access communication system having multicarrier modulation
US11343129B2 (en) Method and system for providing code cover to OFDM symbols in multiple user system
US10009928B2 (en) Method, apparatus and system for random access
EP1766798B1 (en) Frequency-hopped ifdma communication system
EP0700170B1 (en) A method and apparatus for spread spectrum code pulse position modulation
US6320897B1 (en) Multicode spread spectrum communications system
JP3532556B2 (en) High-speed data transmission wireless local area network
US7701839B2 (en) Method and system for multirate multiuser modulation
US7324600B2 (en) Channel estimation in a multi carrier transmit diversity system
US6219374B1 (en) Structure of a coherent dual channel QPSK transceiver using pilot symbols in a code division multiple access system
US20060045000A1 (en) Time-frequency interleaved mc-cdma for quasi-synchronous systems
EP0949765A2 (en) Digital modulation system using extended code set
EP1754313B1 (en) A transmitter and receiver for ultra-wideband ofdm signals employing a low-complexity cdma layer for bandwidth expansion
JP2005245004A (en) Channel estimation and calculation for time-division duplex communication system
US6674790B1 (en) System and method employing concatenated spreading sequences to provide data modulated spread signals having increased data rates with extended multi-path delay spread
CN112398774A (en) Spread spectrum communication method based on orthogonal time frequency expansion
TWI232645B (en) Segment-wise channel equalization based data estimation
US20010026578A1 (en) Code division multiple access transmitter and receiver
JP2002164810A (en) Cyclic shift code division multiplex communication system
EP1128624A2 (en) Code selection for suppression of adjacent channel interference in FDM DPSK
CN112242967B (en) Multi-carrier complementary code single code cyclic shift multiple access method
US11929863B2 (en) Method and system for providing code cover to OFDM symbols in multiple user system
US7773696B1 (en) QBL-MSK mapping for time of arrival (TOA) applications

Legal Events

Date Code Title Description
FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

CC Certificate of correction
FEPP Fee payment procedure

Free format text: PAT HOLDER NO LONGER CLAIMS SMALL ENTITY STATUS, ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: STOL); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 8

SULP Surcharge for late payment

Year of fee payment: 7

AS Assignment

Owner name: WI-LAN, INC., CANADA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ENSEMBLE COMMUNICATIONS, INC.;REEL/FRAME:018268/0592

Effective date: 20040525

AS Assignment

Owner name: WI-LAN, INC., CANADA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FATTOUCHE, MICHAEL;ZAGHLOUL, HATIM;REEL/FRAME:018490/0102

Effective date: 19971014

FPAY Fee payment

Year of fee payment: 12

RR Request for reexamination filed

Effective date: 20130622

B1 Reexamination certificate first reexamination

Free format text: THE PATENTABILITY OFCLAIMS 1, 10, 12-15, 23, 25, 29, 31 AND 32 IS CONFIRMED. CLAIMS 2-9, 11, 16-22, 24, 26-28, 30 AND 33-40 WERE NOT REEXAMINED.

AS Assignment

Owner name: QUARTERHILL INC., CANADA

Free format text: MERGER AND CHANGE OF NAME;ASSIGNORS:WI-LAN INC.;QUARTERHILL INC.;REEL/FRAME:042902/0878

Effective date: 20170601

AS Assignment

Owner name: WI-LAN INC., CANADA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:QUARTERHILL INC.;REEL/FRAME:043165/0898

Effective date: 20170601