A communication device is configured to correlate a first signal with a second signal at a designated interval, the second signal corresponding to the first signal and being received by the communication device where the other communication device transmits a signal including a pulse as the first signal, convert a correlation computation result that is a result of correlating the first signal with the second signal at the designated interval into a format including a matrix product of an expanded modal matrix and an expanded signal vector, the expanded modal matrix including a plurality of elements indicating the correlation computation result obtained when assuming that the signals are received at respective set times, the expanded signal vector being a vector including a plurality of elements, each of which indicates whether or not there is a signal received at each of the set times and amplitude and phase of the signal.