A method of correcting a radio wave strength of a packet received by a communication terminal is disclosed, comprising: displaying a first screen related to the correction of the radio wave strength of the received packet; acquiring first information indicating the radio wave strength of the received packet, according to acceptance of a predetermined user instruction via the first screen; displaying a second screen related to the correction of the radio wave strength of the received packet, at least according to completion of the acquisition; acquiring second information indicating the radio wave strength of the received packet, according to acceptance of a predetermined user operation via the second screen; and deciding a correction value at least based on the acquired first and second information. Thus, it is possible to accurately perform proximity determination of determining that a mobile terminal and an information processing apparatus are within a certain distance.