摘要:
The apparatus for manufacturing the fiberboard is in the form of two vertically opposed endless conveyors upon each of which a fiber layer is formed. Each conveyor has a slanted running portion as a part thereof. A suction box is disposed along the inner surface of each of the slanted running portions so that a fiber layer producing section is formed in each slanted portion. A passage is formed between the conveyors to direct a slurry flow of fibers along each conveyor. The relative speeds of the slurry flow through the passage along the surface of the conveyors is adjusted to be different than the running speed of the conveyors; a supply duct for the slurry flow is disposed in the center of said passage and has an outlet near the upper ends of the fiber layer forming sections. The two layers simultaneously formed can be placed upon each other to form a single layer of fiberboard.
摘要:
A radio communication system for a communication between a base station and a mobile terminal. The radio communication system repeats a signal transmitted from the base station at repeaters that are multistage-connected by a leaky coaxial cable. Each repeater converts a frequency of an input signal into a different frequency and outputs the frequency-converted signal to the leaky coaxial cable connected to the repeater. The repeaters are provided between the leaky coaxial cables connected in series.
摘要:
In a MIMO wireless communication system, the transformation process synthesizes the eigenmodes having a large singular value (i.e. a high effective SNR) and the eigenmodes having a small singular value (i.e. a low effective SNR). Thereby, the former eigenmodes are converted into modes having suppressed effective SNR which do not require a large number of levels of modulation, and the latter eigenmodes are converted into modes having increased effective SNR instead. In a MIMO wireless communication system for eigenmode transmission, a large communication capacity is realized without increasing the number of levels of modulation even in a communication environment capable of achieving a high SNR.
摘要:
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.
摘要:
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.
摘要:
Disclosed is a wireless communication system capable of performing demodulation at the receiving side without substantially deteriorating BER characteristics, regardless of carrier frequency error existing among plural wireless communication systems in SDMA of uplink. The wireless communication system includes plural antennas; a MIMO processor that decomposes a reception signal the plural antennas received from plural transmitters into transmission signals transmitted from the respective transmitters; a FFT processor that carries out OFDM demodulation; and a demapping unit that obtains data from signals which were previously converted into sub-carrier signals by the FFT processor, in which the MIMO processor is installed ahead of the FFT processor for sake of the processing sequence of a receive signal, and even though a carrier frequency offset exists in the reception signal MIMO processing is performed prior to OFDM demodulation to split the reception signal from plural transmitters.
摘要:
In a wireless communication system having a base station and a terminal, it is important to extend the operating life of the terminal in the case of using a battery as the power supply of the terminal. Particularly in the case where a state in which a base station is not present in the range within which the terminal can communicate lasts long, the reduction of the electric power consumption during the standby of the terminal becomes an issue. The terminal monitors the received signal power strength of a signal transmitted by the base station. When the power strength exceeds a prescribed value, it is considered that the base station is present and the base station performs operations for carrying out communication with the base station.
摘要:
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.
摘要:
A wireless communication system comprising a management server, base stations, and a plurality of node terminals, wherein a wireless communication protocol to be applied is switched dynamically based on such indices as but error, packet error rate, the number of times of retransmitting packets, throughput/power consumption that may occur between each base station and nodes.
摘要:
In a wireless communication system for communicating with a plurality of stations at the same point of time with the same frequency using a Space Division Multiple Access (SDMA), wireless resources are allocated by a first decision unit which evaluates performance of each station obtained when the SDMA is used and which determines periods of time to be allocated to groups of stations formed according to the SDMA technique. Using a first evaluation unit and a second evaluation unit to evaluate performance required by each station and each application, the first decision unit allocates the wireless resources to the stations. It is therefore possible that the wireless resources are efficiently allocated to the stations while preventing an event in which the wireless resources are excessive or insufficient for required quality of service.