Repeater device and repeating method

A communication device that is mobile, the communication device comprising:

• a main body;
• and
• a repeater that is physically and detachably coupled to the main body to form a single mobile device, and is separable from the main body, wherein
• the repeater includes:
• a repeater communication unit configured to repeat communication between a first communication device and the main body;
• and
• a second interface configured to communicate with the main body,
• the main body includes:
• a controller configured to separate the repeater inside an area in which communication with the first communication device is possible;
• a communication unit configured to communicate with the first communication device via the repeater outside the area in which communication with the first communication device is possible;
• and
• a first interface configured to communicate with the repeater, and data transmitted from the first interface is transmitted to the first communication device via the second interface and the repeater communication unit,
• wherein all data transmitted from the first interface is transmitted to the first communication device only via the second interface and the repeater communication unit, regardless of whether the main body and the repeater are separated or not separated;
• wherein the main body further includes a sensor, and the communication unit is configured to transmit data obtained by the sensor to the first communication device.