摘要:
There is provided a signal demodulating device, including: a time frequency converting unit (6) for converting a frequency division multiplexing signal on a time axis into a signal on a frequency axis to output a data carrier, a pilot carrier, and a transmission control carrier; an equalizer (7) for equalizing the data carrier and the transmission control carrier according to a characteristic value of a transmission line obtained from the pilot carrier to output an equalized data carrier and an equalized transmission control carrier; a first decoding unit (9) for decoding the equalized transmission control carrier; and a first correcting unit (10) for performing first error-correction on an output of said first decoding unit (9) to output first control information and a first decoding flag that indicates a status of the first error-correction.
摘要:
An average power indicating channel characteristics is outputted from a reference value calculation unit as a reference value. An interference level corresponding to the degree of influence by frequency selective interference is outputted from an interference detection unit. A reliability determination unit determines a carrier that has been subjected to interference on the basis of the reference value and the interference level, to decide a reliability level. An error correction unit performs error correction of a demodulation signal on the basis of the reliability level.
摘要:
An average power indicating channel characteristics is outputted from a reference value calculation unit as a reference value. An interference level corresponding to the degree of influence by frequency selective interference is outputted from an interference detection unit. A reliability determination unit determines a carrier that has been subjected to interference on the basis of the reference value and the interference level, to decide a reliability level. An error correction unit performs error correction of a demodulation signal on the basis of the reliability level.
摘要:
An average power indicating channel characteristics is outputted from a reference value calculation unit as a reference value. An interference level corresponding to the degree of influence by frequency selective interference is outputted from an interference detection unit. A reliability determination unit determines a carrier that has been subjected to interference on the basis of the reference value and the interference level, to decide a reliability level. An error correction unit performs error correction of a demodulation signal on the basis of the reliability level.
摘要:
A reception apparatus for receiving an OFDM signal having a plurality of pilot carriers that transmit predetermined pilot signals at predetermined symbols. The reception apparatus transforms the received OFDM signal to a frequency-domain OFDM signal, determines channel responses corresponding to the transmitted pilot signals for each of the pilot carriers among a plurality of carriers constituting the frequency-domain OFDM signal, determines, based on channel responses corresponding to first, second and third pilot signals transmitted sequentially in a same carrier, a channel response at a symbol between the second pilot signal and the third pilot signal, compensates a waveform distortion in the frequency-domain OFDM signal according to the channel response at the symbol between the second pilot signal and the third pilot signal and outputs the results.
摘要:
There is disclosed a receiver apparatus that can receive OFDM signals. The apparatus comprises: an FFT unit for transforming signals inputted to the apparatus into frequency-domain signals, thereby outputting the transformed signals on a complex symbol-by-complex symbol basis; correlation-calculating units each of which calculates an index indicating a correlation between complex symbols in a respective one of a plurality of groups, each of the plurality groups being a set of a plurality of complex symbols separated from each other by an interval in which a pilot signal is inserted, the groups being selected such that the complex symbols constituting the groups differing from each other; and a judging unit for determining, based on the calculated index for each group, whether or not any index satisfying a predetermined condition is existent, thereby outputting a result of the judgment.
摘要:
Quick resumption of reproduction of received data is achieved with low cost. A receiver for receiving an OFDM signal has a demodulation unit and a transmission mode control unit. The demodulation unit performs, on a received signal, demodulation and detection of establishment of synchronization in accordance with a transmission mode that is a combination of an FFT mode and a guard interval, and outputs a synchronization establishment signal indicating an obtained result of the detection of establishment of synchronization. The transmission mode control unit holds an FFT mode and a guard interval adopted when the synchronization establishment signal indicates establishment of synchronization, and outputs a combination of the held FFT mode and the held guard interval as the transmission mode to be used in the demodulation unit.
摘要:
A reception apparatus for receiving an OFDM signal having a plurality of pilot carriers that transmit predetermined pilot signals at predetermined symbols. The reception apparatus transforms the received OFDM signal to a frequency-domain OFDM signal, determines channel responses corresponding to the transmitted pilot signals for each of the pilot carriers among a plurality of carriers constituting the frequency-domain OFDM signal, determines, based on channel responses corresponding to first, second and third pilot signals transmitted sequentially in a same carrier, a channel response at a symbol between the second pilot signal and the third pilot signal, compensates a waveform distortion in the frequency-domain OFDM signal according to the channel response at the symbol between the second pilot signal and the third pilot signal and outputs the results.
摘要:
Integrating AFC/APC function with waveform equalization function for and reducing the circuit size of a signal wave-form equalizer apparatus. A waveform equalization section is divided into an FFE block as an anterior stage and a DFE block as a posterior stage. An AFC/APC block is provided therebetween. In the AFC/APC block, an AFC/APC coefficient update section updates a coefficient used for removing frequency and phase errors in accordance with an LMS algorithm, and a tap multiplies a modulated signal by the updated coefficient. Error data produced by an error estimation block is used by not only FFE and DFE coefficient update sections but also the AFC/APC coefficient update section for updating the coefficients. That is to say, the waveform equalization section and the AFC/APC block use the error estimation block in common, thereby reducing the circuit size considerably.
摘要:
A demodulation method for tentatively demodulating a modulated input signal by a signal having a fixed frequency to form a tentative complex demodulated signal and then generating a determined complex demodulated signal from the tentative complex demodulated signal. The method includes step (a) of obtaining a determined complex demodulated signal by compensating for the tentative complex demodulated signal based on an optimum phase compensation amount; step (b) of estimating an optimum frequency compensation amount based on a shift in the optimum phase compensation amount during a predetermined cycle; and step (c) of estimating an immediately subsequent optimum phase compensation amount to be used in the steps (a) and (b) performed in repetition, based on the tentative complex demodulated signal, the determined complex demodulated signal, and the optimum frequency compensation amount.