Abstract: A communication apparatus includes a first communication circuit, a second communication circuit, and a controller. The first communication circuit performs wireless communication with a gateway using a first communication system. The second communication circuit performs wireless communication with the gateway using a second communication system having a higher transmission speed than the first communication system. The controller is configured to activate the second communication circuit when the first communication circuit receives an activation request signal from the gateway, and to establish a link between the second communication circuit and the gateway when the first communication circuit receives a connection request signal from the gateway after the second communication circuit is activated.

Abstract: The wireless communication system includes a first wireless terminal (10A) and a plurality of second wireless terminals (10B). The first wireless terminal (10A) transmits a synchronization signal. The synchronization signal comprises a plurality of reference signals each including a reference data indicative of a relation between the corresponding reference signal and a reference time. The second wireless terminal (10B) includes a timer (13) configured to output an activation signal at a regular interval, a control unit (14), and a synchronization unit (15). The control unit (14) activates a wireless receiver (123) each time it receives the activation signal from the timer (13). When the wireless receiver (123) receives the synchronization signal, the synchronization unit (15) refers to the reference data obtained from the earliest reference signal and a reception time of the earliest reference signal, and determines the reference time.

Abstract: The wireless communication system includes a first wireless terminal (10A) and a plurality of second wireless terminals (10B). The first wireless terminal (10A) transmits a synchronization signal. The synchronization signal comprises a plurality of reference signals each including a reference data indicative of a relation between the corresponding reference signal and a reference time. The second wireless terminal (10B) includes a timer (13) configured to output an activation signal at a regular interval, a control unit (14), and a synchronization unit (15). The control unit (14) activates a wireless receiver (123) each time it receives the activation signal from the timer (13). When the wireless receiver (123) receives the synchronization signal, the synchronization unit (15) refers to the reference data obtained from the earliest reference signal and a reception time of the earliest reference signal, and determines the reference time.