摘要:
An AGC unit starts a gain control of the variable gain amplifying unit when a bit saturation occurs in the digital baseband signal output from the A/D converting unit, and starts a gain control of the variable gain amplifying unit when a detection of STS from the digital baseband signal output from the A/D converting unit is started. The AGC unit performs the gain control of the variable gain amplifying unit once when the detection of STS is started, and performs the gain control of the variable gain amplifying unit twice when the bit saturation occurs, namely a larger number of times than when the detection of STS is started.
摘要:
A correlation unit (32) sequentially obtains correlation values between a baseband signal and a reference signal and outputs the obtained reference signal to a section division unit (33). The output of the correlation unit (32) is divided into symbol time periods by the section division unit (33). A section position detection unit (34) detects a largest correlation value in each of sections resulting from the division by the correlation unit (32) and outputs, to a synchronization judgment unit (35), first position information that indicates a relative position of each detected largest correlation value. The synchronization judgment unit (35) detects an arrival of a packet signal and estimates a symbol timing based on the first position information of the sections.
摘要:
A CPU 14 detects a value of an output bit rate of media data output from a buffer 17, detects a value of a free space of the buffer 17, and divides a value resulted from subtracting a decrease ratio set value from the detected value of the free space by a saved period. As a result, a value of a decrease ratio is obtained. In order to decrease a value of an input bit rate of media data input to the buffer 17 in accordance with the value of the output bit rate, the CPU 14 decreases the value of the input bit rate based on an upper limit of the input bit value that is a value resulted from adding the detected value of the output bit rate and the calculated value of the decrease ratio.
摘要:
A correlation unit (32) sequentially obtains correlation values between a baseband signal and a reference signal and outputs the obtained reference signal to a section division unit (33). The output of the correlation unit (32) is divided into symbol time periods by the section division unit (33). A section position detection unit (34) detects a largest correlation value in each of sections resulting from the division by the correlation unit (32) and outputs, to a synchronization judgment unit (35), first position information that indicates a relative position of each detected largest correlation value. The synchronization judgment unit (35) detects an arrival of a packet signal and estimates a symbol timing based on the first position information of the sections.
摘要:
Interfering signals coming at random timings from different radio stations are identified. In order to attain this, a method for storing the characterizing quantity of an interfering signal included in a received signal includes calculating the characterizing quantity of the received signal, determining a probability that a desired signal is included in the received signal, determining that the received signal is an interfering signal when determining that there is no probability that the desired signal is included in the received signal, and storing the characterizing quantity of the received signal as an interfering signal characterizing quantity when it is determined at the received signal determination step that there is no probability that the desired signal is included in the received signal.
摘要:
The noise amount information storage unit 161 stores noise amount information which indicates relationships between gain value of the variable gain amplification units 121 and 125 and the amount of noise included in BB signals output from the down converters 131 and 135. The AGC unit 140 controls the gain value of the variable gain amplification units 121 and 125 so that the power of BB signals output from the down converters 131 and 135 becomes constant. The noise amount estimation unit 162 estimates noise amount of noise corresponding to the controlled gain value of the variable gain amplification units 121 and 125 by referring to the noise amount information stored in the noise amount information storage unit 161. The weight generation unit 170 generates weight matrix based on results of estimations performed by the channel characteristic estimation unit 150 and the noise estimation unit 162.
摘要:
OFDM signals each including a plurality of subcarriers (including data carriers and pilot carriers) orthogonal to each other are received by a plurality of receiver antennas. The received OFDM signals are each OFDM-demodulated into a plurality of receive subcarriers. Based on the plurality of receive subcarriers, the propagation coefficients of a plurality of space paths are estimated. An inverse matrix of a propagation matrix whose elements are the estimated propagation coefficients is calculated. Interference cancellation is performed for the plurality of receive subcarriers by using the inverse matrix, and transmit subcarriers multiplexed in space are estimated. A reliability of the inverse matrix is calculated. A pilot carrier is extracted from the estimated transmit subcarriers, and the extracted pilot carrier is weighted according to the reliability. An error included in the plurality of receive subcarriers is corrected based on the weighted pilot carrier.
摘要:
An object is to identify interfering signals coming at random timings from different radio stations. In order to attain this object, a method for storing the characterizing quantity of an interfering signal included in a received signal comprises a characterizing quantity calculation step of calculating the characterizing quantity of the received signal; a received signal determination step of determining a probability that a desired signal is included in the received signal, and determining that the received signal is an interfering signal when determining that there is no probability that the desired signal is included in the received signal; and an interfering signal characterizing quantity storage step of storing the characterizing quantity of the received signal as an interfering signal characterizing quantity when it is determined at the received signal determination step that there is no probability that the desired signal is included in the received signal.
摘要:
At a time T131, a wireless communication apparatus 11A determines to transmit a data packet, and then performs interference signal detection for a period TA. At a time T132 preceding a time T133 at which the period TA has elapsed since the time T131, the wireless communication apparatus 11A detects a data packet d21 (an interference signal). At a time T134 at which a period TB has elapsed since the time T132 at which the interference signal has been detected, the wireless communication apparatus 11A starts transmitting a data packet d11 to a wireless communication apparatus 12A. At a time T136, the wireless communication apparatus 11A completes the transmission of the data packet d11.
摘要:
In a transfer apparatus to which MIMO-OFDM is applied, a data transmission method and a data reception method are provided in which, even when there are frequency errors varying among transfer paths, the precision of estimation of an inverse propagation coefficient function can be improved, thereby making it possible to suppress a degradation in characteristics. Among symbols composed of a plurality of subcarriers orthognal to each other, the transfer apparatus uses, as a synchronization symbol, a symbol in which predetermined amplitudes and phases are assigned to a plurality of subcarriers spaced at predetermined frequency intervals. The synchronization symbol is divided into transmission antennas to generate a plurality of synchronization subsymbols, which are in turn simultaneously transmitted from a plurality of transmission antennas. A reception apparatus estimates a frequency error for each transfer path based on synchronization subsymbols included in signals received by a plurality of reception antennas, and based on the estimated frequency errors, corrects the received signals.