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公开(公告)号：US20220353009A1
公开(公告)日：2022-11-03
申请号：US17762651
申请日：2019-09-27
IPC分类号： H04L1/00 , H04B7/0413
摘要： Provided is a radio communication system including a radio transmission apparatus including a plurality of transmission antennas and a radio reception apparatus including a plurality of reception antennas. The radio transmission apparatus includes a communication distance measurement unit configured to measure a distance between the plurality of transmission antennas and the plurality of reception antennas, a selection unit configured to select a modulation scheme common to all frequency channels indicating an orthogonality between the plurality of transmission antennas and the plurality of reception antennas, the modulation scheme satisfying an average value of index values for each of the frequency channels according to the distance between the plurality of transmission antennas and the plurality of reception antennas and satisfying a predetermined desired bit error rate, a transmission signal generation unit configured to separate transmission data into the number of all the frequency channels, modulate each item of the separated transmission data by the selected common modulation scheme, and output the transmission signals multiplexed by the number of multiplexing indicating the number of the plurality of transmission antennas to be used, and a radio signal transmitting unit. The radio reception apparatus includes a demodulation unit configured to demodulate a reception signal received by each of the plurality of reception antennas by a demodulation scheme corresponding to the modulation scheme to generate reception data.
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公开(公告)号：US20210119685A1
公开(公告)日：2021-04-22
申请号：US16965959
申请日：2019-02-01
IPC分类号： H04B7/06 , H04B1/00 , H04B1/7085
摘要： A transmission device includes a modulation unit that performs chirp-spread modulation on an input information series to generate a modulation signal; a delay unit that provides, to a plurality of modulation signals obtained by duplicating the modulation signal generated by the modulation unit, delays having lengths different from each other, a difference between the delays being an integral multiple of a reciprocal of a bandwidth of the modulation signal; and a plurality of transmission antennas that transmit the plurality of modulation signals, respectively, to which the delays are provided by the delay unit.
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公开(公告)号：US20220417881A1
公开(公告)日：2022-12-29
申请号：US17779946
申请日：2019-12-02
IPC分类号： H04W56/00
摘要： A synchronization method includes: a first step of transmitting a query command a plurality of times to a communication device configured to perform time synchronization with a base station device connected to a mobile communication network, the query command requesting time information expressed in a first unit, the first unit being lower in accuracy than accuracy of the time synchronization established by the communication device; a second step of determining timing at which the time information obtained in response to the query command is updated; a third step of determining timing to transmit a next query command, based on the timing at which the time information is updated; and a fourth step of acquiring time information with higher accuracy than the first unit, based on time information obtained in response to the query command transmitted at the third step.
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公开(公告)号：US20240187113A1
公开(公告)日：2024-06-06
申请号：US18542340
申请日：2023-12-15
摘要： A receiving apparatus includes: M receivers configured to receive signals based on sound waves propagating in water; M FIR filters configured to perform waveform operation on the signals received by the receivers; a combiner configured to combine output signals of the M FIR filters; and a filter coefficient calculation portion configured to calculate a tap coefficient of the M FIR filters so as to reduce an error of the output signals combined by the combiner. The M FIR filters have a tap length that is shorter than a delay spread that is a possible range between a time of arrival of a direct wave and a time of arrival of a delayed wave of the sound waves.
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公开(公告)号：US20220271848A1
公开(公告)日：2022-08-25
申请号：US17623008
申请日：2019-07-01
摘要： A communication device includes a channel estimation unit configured to estimate an impulse response based on signals of sound waves received by each of a plurality of hydrophones, a long delay removal unit configured to remove a long-delay impulse response from the impulse response to generate a post-removal impulse response, a weighting factor calculation unit configured to calculate a weighting factor based on the post-removal impulse response, and a synthesizing unit configured to synthesize the signals received by each of the plurality of hydrophones based on the weighting factor.
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公开(公告)号：US20210297124A1
公开(公告)日：2021-09-23
申请号：US17258422
申请日：2019-06-25
发明人： Hajime KATSUDA , Yosuke FUJINO , Kazunori AKABANE
摘要： A reception unit in a radio communication apparatus receives wirelessly a signal configured with a preamble from another radio communication apparatus. The synchronization detection unit uses the preamble included in the signal received by the reception unit to detect synchronization with another radio communication apparatus. The signal accumulation unit accumulates a signal extracted from the signal received by the reception unit based on a timing at which the synchronization is detected by the synchronization detection unit. The combining unit combines the signals accumulated in the signal accumulation unit in accordance with a blind adaptive array antenna algorithm. The demodulation unit demodulates the signals combined by the combining unit.
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公开(公告)号：US20220393778A1
公开(公告)日：2022-12-08
申请号：US17774451
申请日：2019-11-12
摘要： A receiving apparatus includes: M receivers configured to receive signals based on sound waves propagating in water; M FIR filters configured to perform waveform operation on the signals received by the receivers; a combiner configured to combine output signals of the M FIR filters; and a filter coefficient calculation portion configured to calculate a tap coefficient of the M FIR filters so as to reduce an error of the output signals combined by the combiner. The M FIR filters have a tap length that is shorter than a delay spread that is a possible range between a time of arrival of a direct wave and a time of arrival of a delayed wave of the sound waves.
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公开(公告)号：US20220321182A1
公开(公告)日：2022-10-06
申请号：US17634207
申请日：2019-08-13
IPC分类号： H04B7/0456 , H04B7/06 , H04W28/02
摘要： A plurality of transmit antennas of a radio transmission device and a plurality of receive antennas of a radio reception device are located under the sea that is a line-of-sight environment, wherein the radio transmission device selects a frequency channel to be used based on an index value per frequency channel indicating orthogonality between the transmit and receive antennas defined based on a distance between the transmit and receive antennas and an angle indicating a direction of arrival of a radio signal, an interval between the plurality of transmit antennas, an interval between the plurality of receive antennas, and a modulation scheme, the distance between the transmit and receive antennas and the angle indicating the direction of arrival of the radio signal estimated by the radio reception device, and a desired bit error rate to be predetermined, selects the modulation scheme for providing a maximum transmission capacity per the selected frequency channel, separates transmission data into a plurality of pieces of transmission data the number of which corresponds to the number of frequency channels, modulates each of the plurality of pieces of transmission data separated in accordance with the selected modulation scheme, and outputs a transmission signal obtained by multiplexing, with a multiplexing order, each of the plurality of pieces of transmission data, the multiplexing order indicating the number of transmit antennas of the plurality of transmit antennas to be used.
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公开(公告)号：US20190150106A1
公开(公告)日：2019-05-16
申请号：US16097494
申请日：2017-05-18
摘要： A time synchronization system includes a first wireless device and a second wireless device. A wireless unit of the first wireless device wirelessly transmits timing information and time information separately, the time information being acquired from a first clock and relating to a transmission time when the timing information was transmitted. A wireless unit of the second wireless device receives the wirelessly transmitted timing information and time information separately. A correction unit of the second wireless device corrects s a second clock on the basis of a reference time indicated by the second clock at a time when the wireless unit received the timing information, and a transmission time obtained from the time information.
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