Wireless communication apparatus and wireless communication system

A wireless communication apparatus which operates in tributary to a control station that performs a time division multiplex communication, the wireless communication apparatus comprising:

• a switch unit that switches on/off a power supplied from a battery;
• a power supply control unit that controls the switch unit;
• a RAM (Random Access Memory) to which power is constantly supplied from the battery;
• a wireless unit that receives a power supplied through the switch unit and performs a wireless communication with the control station;
• a control unit that receives the power supplied through the switch unit;
• and
• a timer unit that measures a time period depending on a given setting, wherein
• when notification of a message with respect to the control station has failed after the establishment of the synchronization with the control station, the control unit writes information indicating non-transmission of the message in the RAM and then outputs a signal of a power supply off to the power supply control unit,
• the power supply control unit turns off the switch unit upon receiving the signal of the power supply off,
• when the switch unit is turned on to supply the power to the control unit through the switch unit, the control unit performs a transmission operation of the message to the control station and reduces the number of retries of the transmission of the message in accordance with the information indicating the non-transmission of the message stored in the RAM,
• when writing the information indicating non-transmission of the message in the RAM, the control unit sets a standby time for a retransmission control in the timer unit, and then outputs the signal of power supply off to the power supply control unit,
• the timer unit notifies the power supply control unit of timer expiration when the set standby time elapses, and the power supply control unit turns on the switch unit upon receiving a notification of the timer expiration to operate to notify the control station of the message again, and
• when the transmission of the message has failed multiple times, the control unit reduces the number of retries of the transmission of the message depending on the number of failures.