In disasters like the Sept. 11, 2001, terror attacks or the earthquake in Japan, communications are often overwhelmed when most needed, U.S. researchers say.Scientists at Georgia Tech College of Computing say they\'ve developed a possible solution, dubbed LifeNet, a mobile ad-hoc network designed for use in highly transient conditions and requiring no infrastructure such as cell towers or traditional landlines.Post-disaster communications often fall to satellite phones, which at $600 or more per unit can be expensive, the researchers say.With LifeNet, people in the field who may not have satellite phones but have smart phones or laptops with WiFi capability can communicate with each other with no other infrastructure and can use the Internet as long as any one of them has access.\"It\'s an independent network you can join,\" Santosh Vempala, professor of computer science, said.\"It doesn\'t need wires, antennas, cell towers and so on, and it works across platforms like laptops and smart phones,\" Vempala said.\"We imagine relief agencies would be able to set up a network right away and communicate about what\'s needed.\"The network starts as soon as a node is put in place with each LifeNet-enabled device acting as both a host client and a router, able to directly route data to and from any other available wireless device.Software developed for LifeNet provides basic communications that consume low bandwidth and are reliable. It doesn\'t allow users to stream video, for example, but it can send text messages for basic communication needs.\"It\'s a trade-off of performance for reliability,\" Vempala said. \"Reliability is really what you need the most in these situations.\"