Patent application number | Description | Published |
20080233904 | TIMING ADJUSTMENT METHOD FOR WIRELESS COMMUNICATION APPARATUS - A wireless communication device including: a transmitter including two DA converter units which convert two digital signals into analog signals; a combiner which combines the analog signals; a distributor which extracts a portion of the combined signal as a feedback signal; an AD converter which converts the feedback signal; an oscillator unit which supplies clock signals to operate the DA converter units and the AD converter; a first separation unit which separates the feedback signal converted by the AD converter into two signals; and a comparator unit which compares at least one of the two digital signals that are obtained by separating the inputted digital signal, or, at least one of the two digital signals that are separately inputted, with the feedback signal separated by the first separation unit, wherein the oscillator unit controls the output clock signals based on a result of the comparison by the comparator unit. | 09-25-2008 |
20080267133 | MIMO WIRELESS COMMUNICATION SYSTEM, MIMO WIRELESS COMMUNICATION APPARATUSES, AND WIRELESS COMMUNICATION METHOD - When a plurality of user stations (STAs) simultaneously communicate with an access point (AP) through an SDMA (Space Division Multiple Access) channel in a MIMO wireless communication system, these STAs control their respective transmission signals such that each signal is received by only a different one of the plurality of antennas at the AP. (It should be noted that the number of these STAs is equal to or smaller than the number of antennas at the AP.) This eliminates the need for the AP to perform MIMO processing, thereby allowing the AP to properly receive and demodulate the signals even if they differ in carrier frequency and transmission timing, which would otherwise result in communication degradation or failure. | 10-30-2008 |
20090034664 | MAXIMUM LIKELIHOOD DECODING METHOD AND RECEIVER - Provided is a maximum likelihood decoding method that includes the steps of; firstly arranging channel impulse responses corresponding to the received signals in a plurality of different orders; secondly specifying the same number of parts as the plurality of different orders in which the channel impulse responses are arranged, so that the received signals are placed in each of the parts; thirdly generating channel matrices each having the channel impulse responses as matrix elements, by using the channel impulse responses arranged in the plurality of different orders, obtaining triangular matrices by applying QR decomposition to the generated channel matrices, and determining at least one combination candidate for each of the parts of the plurality of transmission signals by using the obtained triangular matrices; and fourthly selecting the combination candidates so that a Euclidean distance between the combination candidates determined in the third step is shortest. | 02-05-2009 |
20090060070 | Apparatus and Method for Peak Suppression in Wireless Communication Systems - A method for suppressing the peak-to-average power ratio (PAPR) while limiting deterioration in signal characteristics in wireless communication devices utilizing wireless communication methods (OFDM method, MIMO method) for multiplexing and sending multiple signals. A weight calculator unit sets a large weight for transmit signals whose channel quality is poor, relative to the weight of each base component based on the acquired channel quality. A peak detector unit detects the peak from the signal string after unitary conversion, and extracts a distortion component to apply for suppressing the peak. A peak suppression signal generation unit calculates the peak signal from the distortion component and weight of each base component, to add to each base component, and adds the peak suppression signal to each base component prior to unitary transformation. | 03-05-2009 |
20090060073 | METHOD FOR SUPPRESSING PEAK POWER OF ORTHOGONALLY MULTIPLEXED SIGNAL, PEAK POWER SUPPRESSING CIRCUIT, AND TRANSMITTER - To suppress the peak of the orthogonal multiplex transmission signal which is small in deterioration of the quality of the reception signal by generating the cancellation waveform in synchronization with the timing of the symbol of the transmission signal. There is provided a peak suppressing method that suppresses peaks of an orthogonally multiplexed signal whose orthogonality is ensured in given time units, the method comprising: a first step of detecting the peaks of the orthogonally multiplexed signal; a second step of generating a peak cancellation waveform based on the detected peaks of the orthogonally multiplexed signal; and a third step of removing the peak of the orthogonally multiplexed signal from the orthogonally multiplexed signal using the generated peak cancellation waveform. The second step comprises generating the peak cancellation waveform in said time units of the orthogonally multiplexed signal. | 03-05-2009 |
20090103641 | MAXIMUM LIKELIHOOD DECODING METHOD, EQUIPMENT, AND RECEIVER - Provided is a maximum likelihood decoding method of separating and estimating multiple transmitted signals transmitted by multiple transmitter antennas from multiple received signals received by multiple receiver antennas, comprising: a first step of generating a channel matrix based on channel impulse responses corresponding to the received signals; a second step of dividing the generated channel matrix into multiple sub-matrices, of identifying parts of the received signals corresponding to the sub-matrices obtained through the division, and of transforming the sub-matrices obtained through the division, by using inverse matrices of the sub-matrices obtained through the division; a third step of applying QR decomposition to the transformed sub-matrices to obtain triangular matrices, and of transforming the received signals of the parts by using the obtained triangular matrices; and a fourth step of determining one combination candidate for the parts of the transmitted signals corresponding to the transformed received signals. | 04-23-2009 |
20100020889 | ENCODED SIGNAL ARRANGEMENT METHOD IN MULTI-CARRIER COMMUNICATION AND COMMUNICATION DEVICE - Freedom for relationship between division of a signal processing unit and a pilot signal is improved in a multi-carrier communication system such as OFDM. An encoded signal is divided into resource blocks and the signals are arranged independently of the arrangement of a pilot signal. The signal arranged at the same position as the pilot signal causes a puncture upon transmission. | 01-28-2010 |
20100080315 | MIMO TRANSMISSION MODE SELECTING METHOD AND WIRELESS COMMUNICATION EQUIPMENT - In a radio communication apparatus, a MIMO system deciding section of a transmitter unit decides an object MIMO communication system with reference to a CQI value and a measured rate table while an AMC table controlling section selects an object MCS value according to the decided MIMO communication system and CQI value. The AMC table controlling section changes the MCS value step by step according to a transmission count and a result (success/failure) of the communication. If the communication (receiving) is successful or if the transmission count reaches the maximum value, the controlling section updates the mean value of the measured rate table. At this time, based on a value estimated from the combination of the MIMO communication system, the encoding system, and the modulating system that are used currently, the controlling section changes the reference for selecting another combination that are not used currently. | 04-01-2010 |
20100080320 | CODING AND MODULATION SELECTING METHOD AND WIRELESS COMMUNICATION EQUIPMENT - Disclosed herewith is a radio communication apparatus capable of selecting proper one of plural communication modes such as a MIMO communication system so as to obtain a higher communication rate within a range in which chain retransmission occurrence is prevented. The MIMO system deciding section of the transmitter unit decides a proper MIMO system with reference to the CQI value demultiplexed by a demultiplexer and the AMC table controlling section changes the MCS value step by step according to the transmission count and the result (success/failure) of the communication. Furthermore, the AMC table controlling section updates the mean rate in the measured rate table when the subject data is received successfully or when the transmission count reaches the maximum value. | 04-01-2010 |
20100146365 | ENCODING AND MODULATING METHOD, AND DECODING METHOD FOR WIRELESS COMMUNICATION APPARATUS - Provided is a bit interleaved coded modulation-iterative decoding (BICM-ID) technique suffering a small loss in a transfer rate. A BICM-ID technique allowing a decoder to treat a small processing quantity is also provided. Encoding is carried out according to a code based on an iterative code. Encoded bits are reordered during interleaving processing, subjected to multi-valued modulation through extended mapping, and then transmitted. The extended mapping includes number-of-bits thinning processing of thinning l bits into m bits (m06-10-2010 | |
20110013714 | TRANSMITTING DEVICE, RECEIVING DEVICE, AND SIGNAL PROCESSING METHOD IN RADIO COMMUNICATION SYSTEM - A signal frequency of an interface signal between a baseband unit and a remote radio unit is decreased by downsampling, and the strain of the signal caused by downsampling is compensated for each subcarrier before an IFFT during transmission, and after FFT during reception. | 01-20-2011 |
20110122957 | ADAPTIVE MODULATION SCHEME AND DATA RATE CONTROL METHOD - A radio communication system includes a first radio station for dividing codewords into communication units and transmitting the divided codewords by modulating them in every communication unit, and a second radio station for coupling and decoding signals obtained by demodulating the communication units. The radio stations have common information of first bits, equal to maximum bits per symbol of the communication units, and an encoding type list. The first station modulates and transmits the communication units with a modulation type with second bits. The second radio station receives the communication units modulated by the first radio station, demodulates the communication units with a modulation type with third bits, combines and decodes the demodulated signals with encoding types in the encoding type list, and obtains a result of the decoding, as reception information, by an encoding type in which no error is detected in the result of decoding. | 05-26-2011 |
20110242962 | Method of Multiuser Mimo Wireless Communication and Device of Multiuser Mimo Wireless Communication - The present invention achieves a communication speed close to a theoretical limitation with suppressing a computing amount and without increasing protocol overhead. In a multiuser MIMO wireless communication method according to the present invention, a receive weight matrix is determined based on a channel matrix, the channel matrix is updated by a product of the receive weight matrix and a channel matrix, a transmitted signal is generated in a ZF-DPC method based on the updated channel matrix and transmitted, and the receive weight matrix is multiplied with a received signal and then subjected to a DPC decoding. A method of determining a receive weight matrix is to take a conjugate transpose matrix of a left singular matrix obtained when subjecting the channel matrix to a singular value decomposition. | 10-06-2011 |
20120087265 | WIRELESS COMMUNICATION SYSTEM, INTEGRATED BASE STATION, AND TERMINAL - A frame time having a certain period of time is divided into: a time period (for inter-base-station time division multiplex communication) in which one of the base stations has a transmission right in the simultaneous transmission and carries out inter-base-station time division multiplex communication so as to avoid interference between the base stations; and a time period (for inter-base-station simultaneous communication) for communication which is simultaneously carried out between the plurality of base stations. Furthermore, the time periods are switched for the communication. | 04-12-2012 |
20120120875 | DATA TRANSMISSION METHOD FOR A MOBILE COMMUNICATION SYSTEM - This invention provides a mobile communication system which expanded the operation limitation of the heretofore adopted mobile communication systems and improved the spectrum efficiency greatly. A data transmission method for use in the mobile communication system of the present invention includes means for channel pluralizing by which to expand the Shannon limit and means for interference reduction by which to expand the interference limit. More specifically, a transmitting module comprises M units of modulators and L units of transmitting antennas, generates L units of signals by multiplying M units of modulated signals by a complex matrix consisting of M×L units of elements, and transmits the L units of signals from the L units of transmitting antennas. | 05-17-2012 |
20120134335 | RADIO COMMUNICATION SYSTEM, RADIO COMMUNICATION DEVICE, AND RADIO COMMUNICATION METHOD - A transmitting station having plural antennas includes: a control information calculation unit that calculates control information for use by plural receiving stations according to a multi-user MIMO data transmission scheme; a control information transmission parameter calculation unit that calculates a control information transmission parameter based on spatial channel related information; and a control information transmission signal creation unit that creates a control information transmission signal, using the control information transmission parameter and a pilot signal. A resource element mapping unit maps control information transmission signals onto corresponding resource elements for transmission. On the other hand, the receiving stations each include a control information acquisition unit that acquires plural pieces of control information signaled on the corresponding resource elements, acquire control information destined for each receiving station, and demodulate received signals. | 05-31-2012 |
20130128717 | TRANSMITTING DEVICE, RECEIVING DEVICE, AND SIGNAL PROCESSING METHOD IN RADIO COMMUNICATION SYSTEM - A radio communication system using an orthogonal frequency division multiplexing system, including: a baseband unit; and one or plural remote radio units coupled with the baseband unit through an interface; wherein the baseband unit includes a first sample frequency conversion part that performs a first sample frequency conversion processing that down-samples a transmitting signal transmitted through the interface, wherein the remote radio unit includes a second sample frequency conversion part that performs a second sample frequency conversion processing that up-samples a signal received through the interface, and wherein the baseband unit further includes an inverse fast fourier transform part that generates the transmitting signal by an inverse fast fourier transform, and a transmitter characteristic compensation part that conducts frequency characteristic compensation of the first sample frequency conversion processing and the second sample frequency conversion processing for a signal that has not been subjected to the inverse fast fourier transform. | 05-23-2013 |
20130137474 | TRANSMISSION POWER CONTROL METHOD FOR A WIRELESS COMMUNICATION SYSTEM - Transmission power relative to a propagation path having a variation in gain is controlled to increase communication channel capacity, and a data rate is controlled in accordance with the variation of the increased communication channel capacity. In order to increase the communication channel capacity, the transmission power is determined so that the sum of noise power (=received noise power/propagation path gain) converted into one at a transmitter and the transmission power becomes constant. As a result, contrary to the background art, the transmission power is controlled to be reduced when the propagation path gain decreases and to be increased when the propagation path gain increases. | 05-30-2013 |
20130235905 | GATEWAY WIRELESS COMMUNICATION INSTRUMENT, WIRELESS COMMUNICATION SYSTEM, AND COMMUNICATION CONTROL METHOD - A period is defined to execute the sequences (processes) of communication data acquisition, measuring communication quality, communication quality data acquisition, and channel change. Processing is controlled to execute each process within a time limit set for each process and execute all processes in one cycle. This avoids that a delayed sequence influences and delays other sequences and can suppress delays. If processing fails to finish a sequence, it will resume the same sequence in the next cycle. For communication stations sharing timeslots, there are provided offset periods differing in length before the start of carrier sense in the timeslots for these stations. Consequently, even under a condition in which packet collision may occur, the collision of packets can be avoided by detecting a packet sent to another station by carrier sense. Moreover, by controlling sending priority of packets in the send queue of the gateway, sending delay can be avoided. | 09-12-2013 |
20140044203 | ENCODED SIGNAL ARRANGEMENT METHOD IN MULTI-CARRIER COMMUNICATION AND COMMUNICATION DEVICE - An information transmission method in a multi-carrier wireless communication system in which a transmitter and a receiver conduct communication by using one or plural resource blocks containing plural modulation symbols. One or plural resource blocks correspond to one or plural frequency carriers and one or plural time symbols, including: an operation in which a pilot signal is transmitted by using a part of plural modulation symbols in resource blocks, an operation in which transmission information is encoded by using an error correction code, and an operation in which encoded information is mapped and allocated to modulation symbols, wherein a number of modulation symbols in each resource block in which encoded information is mapped is independent to a number of modulation symbols in resource blocks used to transmit pilot signals, and encoded information mapped and allocated to modulation symbols at the same position as pilot signal is transmitted, are punctured. | 02-13-2014 |
20140105323 | DATA TRANSMISSION METHOD FOR A MOBILE COMMUNICATION SYSTEM - This invention provides a mobile communication system which expanded the operation limitation of the heretofore adopted mobile communication systems and improved the spectrum efficiency greatly. A data transmission method for use in the mobile communication system of the present invention includes means for channel pluralizing by which to expand the Shannon limit and means for interference reduction by which to expand the interference limit. More specifically, a transmitting module comprises M units of modulators and L units of transmitting antennas, generates L units of signals by multiplying M units of modulated signals by a complex matrix consisting of M×L units of elements, and transmits the L units of signals from the L units of transmitting antennas. | 04-17-2014 |