Communication device, control method, and program

A control method of a communication device, the communication device functioning as a master station device or a slave station device in a distributed antenna system and receiving an orthogonal frequency division multiplexing (OFDM) signal transmitted by a time division multiplexing scheme, the distributed antenna system including the master station device connected to a base station and one or more slave station devices relaying a signal between the master station device and a terminal device communicating with the base station, the method comprising:

• receiving the OFDM signal and converting the OFDM signal into a baseband time-axis waveform signal;
• extracting a part of the time-axis waveform signal and calculating a degree of similarity between the extracted signal and a known signal;
• converting a sampling phase of the time waveform signal as the OFDM signal based on the degree of similarity to a known signal calculated;
• executing fast Fourier transform (FFT) on the time-axis waveform signal obtained by the converting the sampling phase;
• extracting a part of a frequency-axis waveform signal on which the FFT is executed and calculating a degree of similarity between the extracted signal and a known signal;
• and
• estimating a switching timing between uplink communication and downlink communication in the communication device based on a result of the calculating the degree of similarity.