Rfid system and radio apparatus

A radio apparatus capable of being used in an RFID system, the apparatus comprising:

• a memory that stores identification information of the radio apparatus;
• a timing generation section that measures time;
• a receiving section that receives an information-request signal requesting transmission of the identification information of the radio apparatus, and that receives an unmodulated-carrier-wave request signal requesting transmission of an unmodulated carrier wave to be used for positioning the radio apparatus;
• and
• a transmission section that transmits a response signal carrying the identification information in the memory in response to receiving the information-request signal, and that transmits the unmodulated carrier wave in an unmodulated-carrier transmission period determined by time period data stored in the memory in accordance with timing from the timing generation section in response to receiving the unmodulated-carrier-wave request signal.

A radio apparatus configured for radio communication with a mobile radio apparatus capable of being used in an RFID system, the radio apparatus comprising:

• a memory;
• a timing generation section that measures time;
• a transmission section that transmits an information-request signal requesting transmission of identification information of the mobile radio apparatus in a first period and that transmits an unmodulated-carrier-wave request signal requesting transmission of an unmodulated carrier wave to be used for positioning the mobile radio apparatus in a second period;
• a receiving section that receives a response signal carrying the identification information, that receives an unmodulated carrier wave in a third period determined by time-period data stored in the memory in accordance with timing from the timing generation section, and that detects a phase difference of the unmodulated carrier wave;
• and
• a control section that outputs the received identification information, and that generates data indicating the detected phase difference of the unmodulated carrier wave.