摘要:
A reception device according to the present invention receives a transmission frame including a synchronization symbol string, having a synchronization symbol repeated multiple times, inserted before a data symbol string. The synchronization symbol is obtained by synthesizing a plurality of sub band symbols which are mutually orthogonal and having different carrier frequencies. The carrier frequencies of the sub band symbols are located at an equal predetermined frequency interval. The synchronization symbol includes a repeated synchronization pattern. The reception device detects a rough carrier frequency error from a phase difference of a synchronization pattern correlation value to correct the frequency, and then detects a residual frequency error from an inter-symbol phase difference of each sub band to correct the frequency. The reception device detects a sampling clock frequency error from an inter-sub band phase difference to correct the frequency. Thus, the demodulation error of the data symbol is reduced.
摘要:
A reception device according to the present invention receives a transmission frame including a synchronization symbol string, having a synchronization symbol repeated multiple times, inserted before a data symbol string. The synchronization symbol is obtained by synthesizing a plurality of sub band symbols which are mutually orthogonal and having different carrier frequencies. The carrier frequencies of the sub band symbols are located at an equal predetermined frequency interval. The synchronization symbol includes a repeated synchronization pattern. The reception device detects a rough carrier frequency error from a phase difference of a synchronization pattern correlation value to correct the frequency, and then detects a residual frequency error from an inter-symbol phase difference of each sub band to correct the frequency. The reception device detects a sampling clock frequency error from an inter-sub band phase difference to correct the frequency. Thus, the demodulation error of the data symbol is reduced.
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.
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.
摘要:
In an OFDM transmission method, in order to compensate any frequency response variation time wise resulted from any distortion in a transmission path, out-of-synchronization with passage of time, frequency drift, and phase shift, and to improve a demodulation characteristic, a PS detector in a receiver receiving an OFDM signal detects a pilot symbol. A PS1 TPFR calculator calculates a frequency response of the transmission path for a first pilot symbol, while a PS2 TPFR calculator calculates a frequency response of the transmission path for a second pilot symbol. Thereafter, a compensation vector calculator calculates compensation vectors from the frequency responses of the transmission path for both the first and second pilot symbols by linear approximation. A frequency response compensator compensates the frequency response variation of subcarriers in a data symbol based on the calculated compensation vectors.
摘要:
An input of an OFDM signal containing known pilot carriers among given subcarriers is separated into subcarriers through Fourier transform in a fast Fourier transform unit. A data carrier phase error estimating unit obtains an amount of phase correction of each subcarrier on the basis of the pilot carriers in the separated subcarriers. A data carrier phase correcting unit corrects the phase of the separated subcarrier signal on the basis of the amount of phase correction. Thus, the phase errors of the subcarriers can be corrected and the OFDM symbols can be demodulated even if a frequency error and a timing error are occurring between the transmitter and receiver.
摘要:
An OFDM receiving apparatus converts a received OFDM signal based on two sampling timing signals to detect reference symbols intermittently inserted in the OFDM signal. Based on the detected reference symbols, a frame synchronization is established. Further, clock components in the reference symbols are extracted, and compared with the sampling timing signals only in the reference symbol duration to obtain a phase error. Based on the phase error, the sampling timing signal is controlled to establish a bit-synchronization. For this purpose, at least two samplers, delayer, and phase error holder are provided.
摘要:
In an OFDM transmission scheme, in order to compensate any frequency response variations time wise resulted from any distortion in a transmission path, out-of-synchronization with passage of time, frequency drift, and phase shift, and to improve a demodulation characteristic, a PS detector in a receiver receiving an OFDM signal detects a pilot symbol. A PS1 TPFR calculator calculates a frequency response of the transmission path for a first pilot symbol, while a PS2 TPFR calculators calculates a frequency response of the transmission path for a second pilot symbol for a second pilot symbol. Thereafter, a compensation vector calculator calculates compensation vectors from the frequency responses of the transmission path for both of the first and second pilot symbols by linear approximation. A frequency response compensatory compensates the frequency response variation of subcarriers in a data symbol based on the calculated compensation vectors.
摘要:
During all or part of a time period during which pattern signals are received, a diversity receiving apparatus allows a gain control section to fix the gain of a gain amplifier section, allows an antenna switching section to sequentially switch the selection of antennas during antenna switching periods which are synchronized with averaging periods, and determines an antenna to receive data contained in a packet, based on the levels of average powers measured by an averaging section on an averaging period-by-averaging period basis.
摘要:
During all or part of a time period during which pattern signals are received, a diversity receiving apparatus allows a gain control section to fix the gain of a gain amplifier section, allows an antenna switching section to sequentially switch the selection of antennas during antenna switching periods which are synchronized with averaging periods, and determines an antenna to receive data contained in a packet, based on the levels of average powers measured by an averaging section on an averaging period-by-averaging period basis.