Base station equipment

1. A base station equipment that communicates with a wireless terminal, comprising:

a timer;

a transmitter that transmits information indicating that the base station equipment is ready to communicate with the wireless terminal;

a receiver for receiving a signal; and

a control unit which:

determines whether or not a power value of a signal transmitted from the wireless terminal to other base station equipment different from the base station equipment, but received from the wireless terminal via the receiver, is greater than a predetermined threshold value;

controls the receiver and the transmitter so as to transfer between a sleep mode where the transmitter stops operation and the receiver operates and an active mode where both of the transmitter and the receiver operate;

judges that the wireless terminal exists near the base station and switches to the active mode when the amount of power of the signal which is transmitted from the wireless terminal to other base station equipment different from the base station equipment, is larger than the predetermined threshold value;

starts transmission of a control signal from the transmitter to provoke communication with the wireless terminal, and operates the timer; and

stops the control signal transmitted from the transmitter when communication is not started even after a predetermined period of time.

2. The base station equipment according to claim 1 , wherein the control unit executes a system synchronization based on a preamble signal which the control unit received from the other base station equipment different from the base station equipment;

stores in advance a time zone at which the preamble signal is transmitted from the other base station equipment;

sets a signal transmitted from the other base station equipment as receiving subject in the time zone; and

sets a signal transmitted from the wireless terminal as receiving subject in an other time zone different from the time zone.

3. A base station equipment that communicates with a wireless terminal, comprising:

a receiving system block, a transmission system block, a timer and a control unit, wherein:

the control unit controls the receiving system block and the transmission system block so as to transfer between a sleep mode where the transmission system block stops operation and the receiving system block operates and an active mode where both of the transmission system block and the receiving system block operate;

compares an amount of power of a signal with a predetermined threshold value when the receiving system block receives the amount of power of the signal which is transmitted from the wireless terminal to other base station equipment different from the base station equipment;

judging that the wireless terminal exists near the base station and switches to the active mode when the amount of power of the signal which is transmitted from the wireless terminal to other base station equipment different from the base station equipment is larger than the predetermined threshold value;

starts transmission of a control signal from the transmission system block and operates the timer; and

stops the control signal transmitted from the transmission system block when communication does not be started even after a predetermined period of time.

4. The base station equipment according to claim 3 , wherein the control unit executes a system synchronization based on a preamble signal which the control unit received from the other base station equipment different from the base station equipment;

stores in advance a time zone at which the preamble signal is transmitted from the other base station equipment;

sets a signal transmitted from the other base station equipment as receiving subject in the time zone; and

sets a signal transmitted from the wireless terminal as receiving subject in an other time zone different from the time zone.