Radio terminal device, radio base station device, radio ranging system, and radio ranging method

A radio base station apparatus in a radio distance measurement system that measures a distance between the radio base station apparatus and a radio terminal apparatus using a pulse signal, the radio base station apparatus comprising:

• a transmitter configured to transmit a pulse signal to the radio terminal apparatus;
• a receiver configured to receive a re-radiation pulse signal and a re-re-radiation pulse signal from the radio terminal apparatus, the re-radiation pulse being generated by the radio terminal apparatus re-radiating the pulse signal transmitted from the radio base station apparatus and the re- re-radiation pulse signal that is being generated by the radio terminal apparatus re-re-radiating the re-radiation pulse signal;
• and
• a measurer that measures a value of a circuit delay time of the radio terminal apparatus based on a time difference between when the re-radiation pulse signal is received at the radio base station apparatus and when the re-re-radiation pulse signal is received at the radio base station apparatus.

A radio distance measurement system that measures a distance between a radio base station apparatus and a radio terminal apparatus using a pulse signal, wherein:

• the radio base station apparatus comprises:
• transmitter configured to transmit a pulse signal to the radio terminal apparatus;
• a receiver configured to receive a re-radiation pulse signal that is and a re-re-radiation pulse signal from the radio terminal apparatus, the re-radiation pulse being generated by the radio terminal apparatus re-radiating the pulse signal transmitted from the radio base station apparatus, and the re-re-radiation pulse signal being generated by the radio terminal apparatus re-re-radiating the re-radiation pulse signal;
• and
• a measurer that measures a value of a circuit delay time of the radio terminal apparatus based on a time difference between when the re-radiation pulse signal is received at the radio base station apparatus and when the re-re-radiation pulse signal is received at the radio base station apparatus;
• and
• the radio terminal apparatus comprises:
• a reception antenna configured to receive the pulse signal from the radio base station apparatus;
• a detector that detects the received pulse signal and outputs a first detection signal based on the received pulse and that detects the re-radiation pulse signal and outputs a second detection signal based on the detected re-radiation pulse signal;
• a generator that generates the re-radiation pulse signal, to be transmitted to the radio base station apparatus, according to the first detection signal, and re-re-radiation pulse signal, to be transmitted to the radio base station apparatus, according to the second detection signal;
• an amplifier configured to amplify the re-radiation, pulse signal and the re-re-radiation pulse signal;
• a transmission antenna configured to transmit the amplified re-radiation pulse signal;
• and
• a timing control that outputs a control signal that controls the amplifier on and off so as to amplify the re-radiation pulse signal and the re-re-radiation pulse signal based on the value of the circuit delay time of the radio terminal apparatus between when the pulse signal is received at the radio terminal apparatus and when the re-radiation pulse signal is transmitted from the radio terminal apparatus.

A radio distance measurement method of measuring a distance between a radio base station apparatus and a radio terminal apparatus using a pulse signal, the method comprising:

• at the radio base station apparatus:
• transmitting a pulse signal to the radio terminal apparatus;
• at the radio terminal apparatus:
• receiving the pulse signal from the radio base station apparatus;
• detecting the received pulse signal and outputting a first detection signal based on the received pulse signal;
• generating a re-radiation pulse signal, to be transmitted to the radio base station apparatus, according to the first detection signal;
• detecting the re-radiation pulse signal and outputting a second detection signal based on the detected re-radiation pulse signal;
• generating a re-re-radiation pulse signal, to be transmitted to the radio base station apparatus, according to the second detection signal;
• amplifiying the re-radiation pulse signal and the re-re-radiation pulse signal;
• and
• transmitting the amplified re-radiation pulse signal and the amplified re-re- radiation pulse signal;
• and
• at the radio base station apparatus:
• receiving the re-radiation pulse signal and the re-re-radiation pulse signal;
• measuring a circuit delay time of the radio terminal apparatus based on a time difference between when the re-radiation pulse signal is received at the radio base station apparatus and when the re-re-radiation pulse signal is received at the radio base station apparatus;
• and
• measuring a response period of a radio wave which includes the circuit delay time of the radio terminal apparatus, based on a time difference between when the pulse signal is transmitted to the radio terminal apparatus and when the re-radiation pulse signal is received from the radio terminal apparatus, and calculating the distance between the radio base station apparatus and the radio terminal apparatus based on the response period and the circuit delay time of the radio terminal apparatus.