Abstract: A base transceiver station equipment, and a radio subsystem using the same, provided a radio interface unit for forming a radio zone, receiving signals transmitted by a mobile station located in that radio zone based on a channel setting procedure or transmitted in a speech state, and measuring the quality of transmission; an identification information acquisition unit for acquiring identification information added to these received signals by a mobile station or identification information indicating a timing when those signals were received; a control unit for interfacing with the radio interface unit and a communication link formed with base station control equipment which takes the lead in the channel setting; and the control unit transmits transmission information given as a signal with a measured quality of transmission exceeding a threshold value among signals received by the radio interface unit and the identification information obtained by the identification information acquisition unit for this sign