In recent years, communications have been unable to be established in some cases because many terminal apparatuses use packet communication services provided by a radio communication system beyond the capacity of a communications infrastructure such as a base station apparatus. Recently, cellular phones called “smartphones” and information communication terminal apparatuses called “tablet terminals” have tended to become widespread. Terminal apparatuses, including cellular phones and information communication terminal apparatuses, could be capable of downloading data of large size such as still images and moving images from a data delivery server via a base station apparatus. Accordingly, in an area where many terminal apparatuses may possibly be present, a case could occur where a data delivery server attempts to simultaneously deliver data of large size to many terminal apparatuses via abase station apparatus that covers communications in that area. If that case happens in a best-effort communication service wherein a plurality of terminal apparatuses could share the bandwidth of communications infrastructures, congestion may possibly occur in a particular communications infrastructure within a radio commutation system.
Specific examples of areas where many terminal apparatuses may possibly be present include, for example, sites for seminars, concert venues, event sites, and rush-hour station yards. In such areas, many terminal apparatuses may be geographically concentrated beyond the capacity of a base station apparatus that covers communications in that area. Data delivered from a data delivery server to many terminal apparatuses within such an area includes, for example, texts delivered from a promoter to guests, site guides with pictures, moving-picture-based schedules, apps needed to attend an event, moving-image data for setting the mood for a concert prior to the start, information for emergency guidance in a venue or station yard, and lost child reports. The data includes information to be shared among many users within the area, and hence an attempt is made to deliver the data to individual terminal apparatuses of many users within the area. Making an attempt to deliver data to many terminal apparatuses within a particular area may cause processing intended for those many terminal apparatuses to be excessively concentrated on a particular communications infrastructure such as a base station apparatus that covers communications in that area, leading to congestion in the particular communications infrastructure.
As described above, in a particular area where many terminal apparatuses could be present, since congestion may possibly occur in a particular communications infrastructure within a radio communication system, it is difficult to simultaneously deliver data of large size from a data delivery server to the many terminal apparatuses.
The following is known as a technology related to a local network for mobile communication devices. A mobile terminal is connected to other mobile terminals so as to form an ad-hoc local network. The mobile terminal determines whether a file requested by a user is available from the local network. When the file is available via the local network, the mobile terminal retrieves the file from the local network. In a case where the file is not available via the local network, when the file is available on a cellular network generated by a base station, the mobile terminal retrieves the file from the cellular network.
In addition, the following is known as a technology related to a wireless ad-hoc network. Each wireless terminal connected to a wireless ad-hoc network retrieves other wireless terminals existing in a communication range by wireless communication to create a neighboring terminal list. Each wireless terminal selects a group leader candidate terminal based on a predetermined selection criterion from the created neighboring terminal list, and carries out a request for a group leader for the selected group leader candidate terminal. The wireless terminal having received the request for a group leader sends acceptance or rejection. Each wireless terminal reports to the other wireless terminals in the neighboring terminal list that the group leader in the own group thereof has been selected.