Communication system

A communication system comprising:

• a base station device;
• and
• a plurality of communication terminal devices capable of radio communication with the base station device,
• wherein the base station device communicates with each of the plurality of communication terminal devices using a self-contained subframe, the self-contained subframe including a downlink signal transmitted from the base station device to the communication terminal device, and an uplink signal transmitted from the communication terminal device to the base station device in response to the downlink signal,
• the self-contained subframe includes a gap duration during which neither the downlink signal nor the uplink signal is transmitted, between a downlink transmission duration during which the downlink signal is transmitted and an uplink transmission duration during which the uplink signal is transmitted, and
• the gap duration is set, b the base station device, to each of the plurality of communication terminal devices such that the gap duration is different for at least two of the plurality of Communication terminal devices,
• wherein the base station device measures a propagation latency for each of the plurality of communication terminal devices by receiving an uplink signal from each of the plurality of communication terminal devices,
• each of the plurality of communication terminal devices measures variations in timing of a signal received from the base station device relative to the respective measured propagation latency, and notifies the base station device of the measured variations, and
• the base station device corrects the respective propagation latency based on the notified variations and sets the gap duration to each of the plurality of communication terminal devices based at least in part on the corrected respective propagation latency.