Communication apparatus and communication method
A communication device includes a channel estimation unit configured to estimate an impulse response based on signals of sound waves received by each of a plurality of hydrophones, a long delay removal unit configured to remove a long-delay impulse response from the impulse response to generate a post-removal impulse response, a weighting factor calculation unit configured to calculate a weighting factor based on the post-removal impulse response, and a synthesizing unit configured to synthesize the signals received by each of the plurality of hydrophones based on the weighting factor.
1. A communication device comprising:
a processor; and
a storage medium having computer program instructions stored thereon, wherein the computer program instructions, when executed by the processor, perform to:
estimate an impulse response based on a signal of a sound wave received individually by a plurality of hydrophones;
remove a long-delay impulse response from the impulse response to generate a post-removal impulse response;
calculate a weighting factor based on the post-removal impulse response; and
synthesize the signal received by each of the plurality of hydrophones based on the weighting factor.
2. A communication device comprising:
a processor; and
a storage medium having computer program instructions stored thereon, wherein the computer program instructions, when executed by the processor, perform to:
filter a signal of a sound wave received individually by a plurality of hydrophones and synthesize the signals;
calculate, with a signal based on a known signal or an unknown signal as a training signal, an error between the signal and the training signal; and
update, based on the error, a weighting factor to be used in filtering.
3. The communication device according to claim 2 , wherein the computer program instructions further perform to:
estimate an impulse response based on the signal;
remove a long-delay impulse response from the impulse response to generate a post-removal impulse response;
filter, based on the post-removal impulse response, the signal based on the known signal or the unknown signal; and
with a signal synthesized with the signal filtered as a training signal, a weighting factor to be used in.
4. The communication device according to claim 3 , wherein the computer program instructions further perform to:
determine, based on the post-removal impulse response, an initial value of the weighting factor.
5. The communication device according to claim 2 , wherein the computer program instructions further perform to:
equalize interference remaining after the filtering;
mitigate the residual interference; and
adaptively update, based on the signal based on the known signal or the unknown signal, a weighting factor.
6. The communication device according to claim 5 , wherein the computer program instructions further perform to:
filter the signal based on the known signal or the unknown signal with a regression filter to reproduce a replica signal of the signal; and
adaptively update, with the replica signal as a training signal, a weighting factor.
7. A communication method comprising:
estimating an impulse response based on a signal of a sound wave received individually by a plurality of hydrophones;
removing a long-delay impulse response from the impulse response and generating a post-removal impulse response;
calculating a weighting factor based on the post-removal impulse response; and
synthesizing, based on the weighting factor, the signal received by each of the plurality of hydrophones.
8. A communication method comprising:
filtering a signal of a sound wave received individually by a plurality of hydrophones and synthesizing the signals; and
calculating, with a signal based on a known signal or an unknown signal as a training signal, an error between the signal and the training signal and updating a weighting factor to be used in the filtering.