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6714511 |
OFDM transmission/reception apparatus having a guard interval length changing function
The subtractor of the reception system calculates the channel quality using an optimal guard interval length detection signal inserted into one carrier by the transmission system, then the optimal...
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6711124 |
Time interval based channel estimation with transmit diversity
A wireless communication system with transmit diversity scales a training sequence simultaneously transmitted by two or more antennas over two or more time intervals in a manner that allows a...
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6711120 |
Orthogonal frequency division multiplexing based spread spectrum multiple access
An orthogonal frequency division multiplexing (OFDM) based spread spectrum multiple access system using offsetting between cells, and in particular, the use of tone offsetting and time offsetting,...
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6711123 |
Receiving apparatus for OFDM communication system
In a receiving apparatus, which receiving apparatus performs timing synchronization in OFDM transmission by using specific known patterns included in a reception signal, a correlation value...
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6711121 |
Orthogonal code division multiplexing for twisted pair channels
A plurality of data signals are separated into parallel bit streams with each parallel stream having a bandwidth characteristic such that the combined cumulative effect of all the individual...
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6700865 |
Diversity receiver
An object of the present invention is to provide a diversity receiver having an excellent anti-multi-path fading characteristic in a further simple structure. A diversity receiver according to the...
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6680901 |
OFDM demodulator
In order to shorten delay time in a synchronization circuit in an OFDM demodulator, with respect to a preamble for estimating carrier frequency/channel characteristic, the synchronization circuit...
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6680928 |
Communications system and method for multi-carrier orthogonal coding
In CDMA systems, a message to be transmitted is redundantly coded for transmission using a combination of error-correction coding and a spread-spectrum access code. The coded message is modulated...
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6678339 |
Globally optimum maximum likelihood estimation of joint carrier frequency offset and symbol timing error in multi-carrier systems
A method for synchronizing multi-carrier signals in an orthogonal frequency division modulation (OFDM) data transmission system is disclosed which provides maximum likelihood estimation of timing...
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6674712 |
Device and method for generating quaternary complex quasi-orthogonal code and spreading transmission signal using quasi-orthogonal code in CDMA communication system
A method for generating a quaternary complex quasi-orthogonal code in a CDMA communication system is disclosed. The method comprises generating an M-sequence and then generating specific sequences...
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6671266 |
Device and method for controlling powers of orthogonal channel and quasi-orthogonal channel in CDMA communication system
A power control device for a CDMA communication system using different kinds of spreading codes. In the power control device for a base station device, a first channel generator generates a first...
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6667961 |
Device and method for implementing handoff in mobile communication system
A handoff implementing device and method in a mobile communication system. The handoff implementing device including a base station transmitter and a mobile station receiver. The base station...
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6657950 |
Optimal filtering and upconversion in OFDM systems
Systems and methods for converting a baseband OFDM signal to an IF signal while minimizing lengthening of the impulse response duration experienced by the OFDM signal. A conversion technique...
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6654340 |
Differential OFDM using multiple receiver antennas
Systems and methods for optimally receiving differential encoded OFDM signals via multiple antennas. These techniques may exploit spatial diversity without knowledge of channel characteristics....
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6654339 |
Synchronization symbol structure using OFDM based transmission method
The present invention proposes a method for generating synchronization bursts for OFDM transmission systems. The symbols of a predefined symbol sequence are mapped according to a predefined mapping...
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6650617 |
Reduced complexity FFT window synchronization for an orthogonal frequency division multiplexing system
An Orthogonal Frequency Division Multiplexing (OFDM) receiver that compensates for FFT window drift by extracting pilots from a fast Fourier transformed and equalized OFDM signal, and processing...
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6647025 |
OFDM reception apparatus
Multiplier 103 calculates the correlation value of the received signal with the one-symbol-delayed received signal, integrator 104 integrates the calculated correlation value, subtracter 105 ...
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6646979 |
Methods of dynamically assigning channel codes of different lengths in wireless communication systems
In a wireless communication system, unique methods are presented to dynamically assign channel codes of different lengths in a manner to maintain orthogonality among assigned channels. In one...
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6643281 |
Synchronization preamble method for OFDM waveforms in a communications system
A highly bandwidth-efficient communications method is disclosed that enables remote stations to synchronize in time and frequency to their serving base station. The invention enables a base station...
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6628605 |
Method and apparatus for efficiently transmitting multiple data signals
A switch suitable for use in high-bandwidth environments is disclosed. The switch eliminates the need for inter-stage jitter compensation by determining the timing signals associated with each data...
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6628606 |
Coarse frequency offset estimator in orthogonal frequency division multiplexing receiver and method thereof
Coarse frequency offset estimation method and device in an orthogonal frequency division multiplexing (OFDM) receiver are provided. The coarse frequency offset estimation device includes a buffer...
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6625113 |
Digital signal frame and interleaver synchronizer
A receiver of digital information typically performs a frame synchronization finction to locate the beginning of a frame of within received information. Frame and interleaver synchronization...
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6621875 |
High data rate CDMA wireless communication system using variable sized channel codes
A method and apparatus for high rate CDMA wireless communication is described. Variable data rates are generated using a set of different encoder, interleaver, and symbol repetition configurations....
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6611493 |
Communication, transmission and receiving method and apparatus using orthogonal frequency division multiplexing modulation system
A communication method in an orthogonal frequency division multiplexing modulation communication system includes a transmission apparatus in which a frequency bandwidth of a signal modulated in...
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6611494 |
Orthogonal sequence generator
A set of orthogonal sequences (e.g., Hadamard sequences) is decomposed into a set of basis vectors and sets of coefficients, where each set of coefficients represents a particular “vector...
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6609010 |
Dual frequency band transceiver
A dual frequency band transceiver ( 10 ) is provided adapted to be operated into different transmission frequency bands. A control unit ( 8 ) controls a switching ( 6 ) between a first transmission...
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6606296 |
Data transmission method and radio system
The invention relates to a data transmission method and a radio system comprising at least one base station and a subscriber terminal. In this method each transmitter places reference carriers by...
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6603735 |
PN sequence identifying device in CDMA communication system
A PN sequence identifying device in a receiver in an asynchronous CDMA communication system. The receiver receives first OGCs on a primary sync channel and second OGCs on a secondary sync channel...
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6603961 |
Diversity receiving apparatus
A diversity receiving apparatus for receiving data that has been primarily modulated and then secondarily modulated includes a plurality of uni-directivity antennas arranged so that they orient in...
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6594226 |
Apparatus and method of enhancing transmit diversity
Disclosed is a method and apparatus for enhancing diversity gain without reducing data rate by increasing the number of antenna elements and configuring the antenna elements for improving...
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6587452 |
High performance signal structure with multiple modulation formats
A mapping memory, for use with a transmitter, for mapping a first signal segment and a second signal segment of a packet so that each signal segment has the same average power level. Each signal...
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6584068 |
Prototype signals construction for multicarrier transmission
This invention concerns a multicarrier signal designed to be transmitted to digital receivers, especially in a non-stationary transmission channel. The multicarrier signal corresponds to the...
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6580705 |
Signal combining scheme for wireless transmission systems having multiple modulation schemes
In a wireless transmission system that transmits the same information in parallel using two or more different types of modulation schemes, such as a satellite-based digital audio transmission...
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6570889 |
Transmitter and transmitting method increasing the flexibility of code assignment
According to the present invention a transmitter and a transmitting method for communicating data symbols over a communication channel, for example, according to the CDMA system is presented. The...
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6567374 |
Data and pilot mapping in an OFDM system
The present invention relates to a wireless transmission method and a wireless transmission system using an OFDM system comprising a plurality of equally spaced subcarriers. According to the...
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6567393 |
Dynamic reselection of CDMA spreading codes
A CDMA system transmits from a base station to a plurality of mobile stations or from mobile station to base station on a shared frequency band, each mobile station's data being spread by a...
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6567390 |
Accelerated message decoding
A message that has its energy spread over a frame of encoded data is decoded. First, encoded data are received so as to obtain a quantity of the encoded data that is less than all the encoded data...
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6563786 |
Orthogonal frequency division multiplexing system with selectable rate
An OFDM system uses a normal mode which has a symbol length T, a guard time TG and a set of N sub-carriers, which are orthogonal over the time T, and one or more fallback modes which have symbol...
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6556557 |
Method and system for reducing of peak-to-average power ratio of transmission signals comprising overlapping waveforms
The present invention provides a method and system for reducing the peak to average power ratio (PAP) of a signal with low computational complexity. According to one embodiment, the present...
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6552996 |
OVSF code system and methods
A code indexing method for orthogonal variable spreading factor (OVSF) codes introduces a single number mapped to the each code. The new code number itself not only provides the code signature, but...
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6553019 |
Communications system employing orthogonal frequency division multiplexing based spread sprectrum multiple access
Tone sequences in a frequency hopping arrangement are generated and assigned by advantageously employing a combination of a sequence generator and a sequence assignor to generate sequences and...
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6552995 |
Spectrum diffusion signal analyzer and method of analyzing diffusion signal
According to the present invention, the inputted spectrum diffusion signal is orthogonal-transformed ( 16 ), and then, the common mode output Zre and the orthogonal mode output Zim are respectively...
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6549581 |
Transmitter and method to cancel interference in OFDM communication
According to the present invention a transmitter for the wireless transmission of information data for example according to the OFDM system is provided. The transmitter comprises a random...
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6545975 |
Method of enhancing security for the transmission of information
Quasi-Walsh function systems are developed which allow multiple access as well as spectral spreading for interception and jamming prevention. Mutual interference is minimal due to orthogonal...
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6529472 |
Generation and decoding of multi-carrier signal
A first orthogonal-multi-carrier signal is generated through N-point inverse discrete Fourier transform. The first orthogonal-multi-carrier signal has “N” or less orthogonal multiple carriers,...
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6522626 |
Power line communications system and method of operation thereof
An Orthogonal Frequency Division Multiplexed (OFDM) power line communications system comprising a power line for distributing electricity to a plurality of premises and a communication station...
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6519244 |
CDMA transmitter capable of reducing transmission power
In a CDMA transmitter operable in response to a plurality of input data signals to produce a transmission signal, a dummy symbol is generated by a dummy symbol generator to reduce a peak value of a...
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6512753 |
Device and method for spreading channels in mobile communication system
Disclosed is a channel spreading device for a base station device in a CMDA communication system for spreading input symbols using a first quasi-orthogonal code having a first length or channel...
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6512737 |
Stacked carrier discrete multiple tone communication system
A “stacked-carrier” spread spectrum communication system based on frequency domain spreading that multiplies a time-domain representation of a baseband signal by a set of superimposed, or...
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6510133 |
Multi-carrier transmission method and data transmitter
Equipped with a plurality of mapping blocks 102 and 103 that carry out mappings of different rates, signals subjected to low-speed mapping are placed in the periphery of a band to which a...
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