Wireless sensor network system, information gathering apparatus, sensor device, and connection method for use in wireless sensor network

A wireless sensor network information gathering apparatus that is wirelessly connected via an adaptive array antenna to a plurality of sensor devices each having a non-directional antenna , and that gathers information detected by the plurality of sensor devices, the apparatus comprising:

• a first directivity-changing section that, when the information gathering apparatus receives a transmission request from an unconnected sensor device, performs at least one of setting the adaptive array antenna to be non-directional and changing a directivity of the adaptive array antenna, and that receives a signal transmitted from at least one of the unconnected sensor device and the unconnected sensor device and a connected sensor device;
• and
• a second directivity-changing section to change the directivity of the adaptive array antenna in accordance with a reception state of the signals transmitted from the at least one of the unconnected sensor device and the unconnected sensor device and the connected sensor device.

A wireless sensor network sensor device that is wirelessly connected to an information gathering apparatus having an adaptive array antenna, and that transmits detected information to the information gathering apparatus, the device comprising:

• a transmitter that transmits a transmission request for connecting to the information gathering apparatus, and
• an incorporating section to incorporate a transmission request from another sensor device into a signal being transmitted from the sensor device upon receiving the transmission request from the another sensor device, and to transmit the signal to the information gathering apparatus.