Abstract: A communication device includes: a receiving unit that receives first peripheral device data, which relates to a movement state of a first peripheral device, and second peripheral device data, which relates to a movement state of a second peripheral device; an acquiring unit that acquires host device data which relates to a movement state of a host device; a control unit that calculates host device collision prediction time between the first peripheral device and the host device and other device collision prediction time between the first peripheral device and the second peripheral device, and shortens a transmission interval of the host device data when the host device collision prediction time is shorter than a predetermined value and the host device collision prediction time is shorter than the other device collision prediction time; and a transmission unit that transmits the host device data according to the transmission interval.

Abstract: A communication device includes: a receiving unit that receives first peripheral device data, which relates to a movement state of a first peripheral device, and second peripheral device data, which relates to a movement state of a second peripheral device; an acquiring unit that acquires host device data which relates to a movement state of a host device; a control unit that calculates host device collision prediction time between the first peripheral device and the host device and other device collision prediction time between the first peripheral device and the second peripheral device, and shortens a transmission interval of the host device data when the host device collision prediction time is shorter than a predetermined value and the host device collision prediction time is shorter than the other device collision prediction time; and a transmission unit that transmits the host device data according to the transmission interval.

Abstract: A download method forms a download user network with a plurality of user terminals which are going to download the same data. The delivery server divides the data into data portions, and assigns the data portions to the respective user terminals belonging to the download user network. Then each of the user terminals downloads the assigned data portion from the delivery server. Thereafter the downloaded data portions are mutually transmitted among the user terminals within the download user network so that each of the user terminals can obtain all the data portions which constitute the data. Each of the user terminals combines the obtained data portions into the original data. Thus the data is efficiently downloaded to the plurality of user terminals.

Abstract: A download method forms a download user network with a plurality of user terminals which are going to download the same data. The delivery server divides the data into data portions, and assigns the data portions to the respective user terminals belonging to the download user network. Then each of the user terminals downloads the assigned data portion from the delivery server. Thereafter the downloaded data portions are mutually transmitted among the user terminals within the download user network so that each of the user terminals can obtain all the data portions which constitute the data. Each of the user terminals combines the obtained data portions into the original data. Thus the data is efficiently downloaded to the plurality of user terminals.