NEC Corp developed what it claims is the world's first technology to form a data distribution network without 3G/LTE or wireless LAN access points by using only mobile devices such as smartphones.
The new technology enables multicast delivery by using only data transmission among mobile devices. It is targeted at environments where many people are connected to a network such as event and disaster sites.
When network facilities are damaged or cut off from power in a time of disaster, or at event sites and major stations where many people gather, so many mobile devices are connected to a network that transmission speed drastically lowers, making it difficult to connect to the network.
According to NEC, the new technology is the world's first DTN (delay/disruption/disconnection-tolerant network) multicast delivery technology. Conventional multicast delivery technologies have been used for applications that can tolerate lack of data during delivery of video content or video streaming. On the other hand, the new technology eliminates lack of data during delivery by making many receiving devices complement the data for one another.
Also, an application software installed on each mobile device controls the data transmission timing of multiple devices that radio waves from the device can reach in increments of several tens of milliseconds to several hundreds of milliseconds (autonomous decentralized control). The new technology ensures that multiple devices do not transmit data at the same time, preventing packet collision and lowering of transmission rate caused by access concentration.
Furthermore, NEC developed a technology of deciding when to transmit data from each mobile device in consideration of priority of information and the state of an entire network in collaboration with Tohoku University. High-priority information such as warnings and requests for help is preferentially transmitted and widely spread with low delay.