A Geocast Based File Transfer Protocol

Teams of operators need to send and receive large data files while in the field, such as imagery, maps, and audio messages. However, traditional data networking techniques do not perform well under the challenges of realistic field conditions: the size of data to be transferred strains precious resources, sporadic connectivity causes excessive and fruitless retry transmissions, and one-to-one messaging needlessly wastes resources when geographic density of recipients is high. This paper describes the Geocast File Transfer (GFT) Protocol, which is based upon a scalable geocast protocol. It exploits the efficiency of geocast, one-to-many messages, and request pooling in retry phases to significantly reduce costs and improve file transfer success over traditional unicast based file transfer methods in field conditions. GFT is evaluated and compared analytically, in simulation, and through field tests of an implemented smartphone-based system.