Timing detection method, communication system and receiving apparatus
The transmission apparatus intermittently transmits a physical frame of a transmitted signal. The receiving apparatus includes a correlation calculation unit and a determination unit. The correlation calculation unit calculates a correlation between the received signal and each of the correlation sequences subjected to Doppler shift of a plurality of types of shift amounts. The determination unit determines that the physical frame has been received in a case where any one of the calculation results obtained by the correlation calculation unit exceeds the threshold.
1 . A timing detection method comprising:
intermittently transmitting, by a transmission apparatus, a physical frame of a transmitted signal;
calculating, by a receiving apparatus, a correlation between a received signal and each of correlation sequences subjected to Doppler shift of a plurality of types of shift amounts; and
determining, by the receiving apparatus, that the physical frame has been received in a case where any one of calculation results exceeds a threshold,
wherein each of the plurality of types of shift amounts is any value obtained by multiplying a reciprocal of a product of a sequence length of a correlation sequence and a symbol rate of the physical frame by an integer.
2 . A timing detection method comprising:
calculating a correlation between a received signal having been transmitted from a transmission apparatus that intermittently transmits a physical frame of a transmitted signal and each of correlation sequences subjected to Doppler shift of a plurality of types of shift amounts; and
determining that the physical frame has been received in a case where any one of calculation results exceeds a threshold,
wherein each of the plurality of types of shift amounts is any value obtained by multiplying a reciprocal of a product of a sequence length of a correlation sequence and a symbol rate of the physical frame by an integer.
3 . A communication system comprising a transmission apparatus and a receiving apparatus,
wherein the transmission apparatus intermittently transmits a physical frame of transmitted signal, and
the receiving apparatus includes:
a correlation calculation circuitry that calculates a correlation between a received signal and each of correlation sequences subjected to Doppler shift of a plurality of types of shift amounts; and
a determination circuitry that determines that the physical frame has been received in a case where any one of calculation results obtained by the correlation calculation circuitry exceeds a threshold,
wherein each of the plurality of types of shift amounts is any value obtained by multiplying a reciprocal of a product of a sequence length of a correlation sequence and a symbol rate of the physical frame by an integer.
4 . A receiving apparatus comprising:
a correlation calculation circuitry that calculates a correlation between a received signal having been transmitted from a transmission apparatus that intermittently transmits a physical frame of a transmitted signal and each of correlation sequences subjected to Doppler shift of a plurality of types of shift amounts; and
a determination circuitry that determines that the physical frame has been received in a case where any one of calculation results obtained by the correlation calculation circuitry exceeds a threshold,
wherein each of the plurality of types of shift amounts is any value obtained by multiplying a reciprocal of a product of a sequence length of a correlation sequence and a symbol rate of the physical frame by an integer.
5 . The receiving apparatus according to claim 4 ,
wherein the plurality of types of shift amounts are values shifted by a predetermined Doppler frequency, and
a ratio of signal power and noise power of a received signal calculated using a correlation sequence of the predetermined Doppler frequency matches a ratio of signal power and noise power of a received signal at a detection threshold calculated using a correlation sequence of a reference shift amount in a case where one of the plurality of types of shift amounts is regarded as the reference shift amount.
6 . The receiving apparatus according to claim 4 ,
wherein the received signal has been transmitted underwater.