摘要:
A demodulating semiconductor integrated circuit device used in a wireless communication system of an FM-modulation scheme, wherein a circuit for canceling a frequency offset is made of a digital circuit, so as to make a high-accuracy decision as to received data and prevent error frequency offset cancel due to a pseudo pattern contained in the received data. Consequently, a high-accuracy received data decision is carried out.
摘要:
A demodulating semiconductor integrated circuit device used in a wireless communication system of an FM-modulation scheme, wherein a circuit for canceling a frequency offset is made of a digital circuit, so as to make a high-accuracy decision as to received data and prevent error frequency offset cancel due to a pseudo pattern contained in the received data. Consequently, a high-accuracy received data decision is carried out.
摘要:
A demodulating semiconductor integrated circuit device used in a wireless communication system of an FM-modulation scheme, wherein a circuit for canceling a frequency offset is made of a digital circuit, so as to make a high-accuracy decision as to received data and prevent error frequency offset cancel due to a pseudo pattern contained in the received data. Consequently, a high-accuracy received data decision is carried out.
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.