Wireless communication device, communication system and control method

A communication system that performs communication between a base station and a wireless communication device,

• wherein the base station comprises:
• a plurality of antenna elements that are spatially disposed at an interval of at least λ/2 (λ is the wavelength of radio waves used);
• a phase shift unit that detects phase of a signal received by each of the plurality of antenna elements, and shifts phase of a signal transmitted by the plurality of antenna elements based on a result of such detection;
• and
• a supply unit that supplies a signal, whose phase has been shifted by the phase shift unit, to the plurality of antenna elements by sequentially switching the signal so as to periodically rotate directivity characteristics of composite waves generated by the plurality of antenna elements, and
• wherein the wireless communication device comprises:
• a reception unit that receives radio waves emitted from the plurality of antenna elements of the base station, and converts the radio waves into signals;
• a signal processing unit that executes predetermined signal processing on the signals converted by the reception unit;
• a detection unit that detects control channels from the signals processed by the signal processing unit;
• a field intensity calculation unit that calculates field intensity for one period of the control channel in the composite waves that periodically rotate;
• and
• a control unit that controls the reception unit to periodically receive composite waves of the control channels, based on a result calculated by the field intensity calculation unit.

A control method for a wireless communication device that communicates with a base station that includes:

• a plurality of antenna elements that are spatially disposed at an interval of at least λ/2 (λ is the wavelength of radio waves used);
• a phase shift unit that detects phase of a signal received by each of the plurality of antenna elements, and shifts phase of a signal transmitted by the plurality of antenna elements based on a result of such detection;
• and a supply unit that supplies a signal, whose phase has been shifted by the phase shift unit, to the plurality of antenna elements by sequentially switching the signal so as to periodically rotate directivity characteristics of composite waves generated by the plurality of antenna elements, the control method comprising:
• a reception conversion step of receiving radio waves emitted from the plurality of antenna elements of the base station, and converts the radio waves into signals;
• a signal processing step of executing predetermined signal processing on the signals converted in the reception conversion step;
• a detection step of detecting control channels from the signals processed in the signal processing step;
• a field intensity calculation step of calculating field intensity for one period of the control channel in the composite waves that periodically rotate;
• and
• a control step of controlling the reception conversion step to periodically receive composite waves of the control channels, based on a result calculated in the field intensity calculation step.