Control method of wireless communication system, wireless communication system, adjustment method of array weight vector, and wireless communication device

A wireless communication system comprising first and second communication devices,

• the first communication device comprising:
• an antenna array including a plurality of antenna elements;
• and
• an array weight vector (AWV) control circuit that changes at least one of amplitudes and phases of transmission signals or received signals of the plurality of antenna elements,
• the first and second communication devices being configured to perforin an AWV determination process in cooperation,
• the AWV determination process comprising:
• (a) transmitting a training signal between the first and second communication devices, the first communication device being configured to transmit or receive the training signal while scanning a beam pattern, and the second communication device being configured to receive or transmit the training signal with a fixed beam pattern;
• (b) determining at least one primary direction of departure (DOD) or direction of arrival (DOA) in the first communication device based on a relation between DODs or DOAs of the training signal in the first communication device and a received signal characteristic of the training signal in the first or the second communication device;
• (c) transmitting the training signal again between the first and second communication devices, the first communication device being configured to transmit or receive the training signal while scanning a beam pattern in a state where signal emission toward the at least one primary DOD or signal reception from the at least one primary DOA is restricted, and the second communication device being configured to receive or transmit the training signal with a fixed beam pattern;
• (d) determining at least one secondary DOD or DOA based on a relation between DODs or DOAs of the training signal in the first communication device and a received signal characteristic of the training signal in the first or the second communication device obtained while restricting signal emission toward the at least one primary DOD or signal reception from the at least one primary DOA;
• (e) obtaining at least one primary AWV each having a main beam direction or a sub-beam direction pointing to respective one of the at least one primary DOD or DOA and at least one secondary AWV each having a main beam direction or a sub-beam direction pointing to respective one of the at least one secondary DOD or DOA;
• and
• (f) selectively using the at least one primary AWV and the at least one secondary AWV in communication between the first and second communication devices.

An AWV adjustment method for a wireless communication device comprising an antenna array, and an array weight vector (hereinafter called “AWV”) control circuit that changes at least one of amplitudes and phases of signals received by a plurality of antenna elements constituting the antenna array,

• the AWV adjustment method comprising:
• (a) receiving a training signal transmitted from a device to be communicated with while scanning a beam direction of the antenna array in the wireless communication device;
• (b) determining at least one primary direction of arrival (hereinafter called “first DOA”) based on a reception result of the training signal in the wireless communication device;
• (c) receiving the training signal while scanning a beam direction of the antenna array in a state where signal reception from the first DOA is restricted in the wireless communication device;
• (d) determining at least another direction of arrival (hereinafter called “second DOA”) different from the first DOA in the wireless communication device based on a reception result of the training signal obtained while restricting signal reception from the first DOA;
• (e) obtaining an AWV having a main beam direction or a sub-beam direction pointing to the first DOA and an AWV having a main beam direction or a sub-beam direction pointing to the second DOA;
• and
• (f) using the AWV obtained in the step (e) in communication with the device to be communicated with.

A wireless communication device comprising:

• an antenna array;
• an array weight vector (hereinafter called “AWV”) control unit that changes at least one of amplitudes and phases of signals received by a plurality of antenna elements constituting the antenna array;
• a processing unit that determines an AWV to be used in communication with a device to be communicated with, and supplies the determined AWV to the AWV control unit;
• and
• a receiving unit that performs a demodulation process on a signal received by the antenna array,
• wherein the processing unit:
• determines at least one primary direction of arrival (hereinafter called “first DOA”) based on a reception result of a training signal being transmitted by the device to be communicated with and received by the receiving unit while scanning a beam direction of the antenna array;
• determines at least another direction of arrival (hereinafter called “second DOA”) different from the first DOA based on a reception result of the training signal being received by the receiving unit while scanning a beam direction of the antenna array in a state where signal reception from the first DOA is restricted;
• and
• obtains an AWV having a main beam direction or a sub-beam direction pointing to the first DOA and an AWV having a main beam direction or a sub-beam direction pointing to the second DOA in order to supply the obtained AWVs to the AWV control unit.

A wireless communication device comprising:

• an antenna array;
• an array weight vector (hereinafter called “AWV”) control unit that changes at least one of amplitudes and phases of signals transmitted by a plurality of antenna elements constituting the antenna array;
• a processing unit that determines an AWV to be used in communication with a device to be communicated with, and supplies the determined AWV to the AWV control unit;
• and
• a transmitting unit that generates a transmission signal to be transmitted from the antenna array,
• wherein the processing unit:
• determines at least one primary direction of departure (hereinafter called “first DOD”) based on a result of wireless transmission of a training signal being generated by the transmission unit while scanning a beam direction of the antenna array;
• determines at least another direction of departure (hereinafter called “second DOD”) different from the first DOD based on a result of wireless transmission of the training signal while scanning a beam direction of the antenna array in a state where signal emission to the first DOD is restricted;
• and
• obtains an AWV having a main beam direction or a sub-beam direction pointing to the first DOD and an AWV having a main beam direction or a sub-beam direction pointing to the second DOD in order to supply the obtained AWVs to the AWV control unit.