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MinuteMan on the March By Jeff Goldman, Oct 07 2002 A project currently underway at UCLA is turning science fiction into reality by creating self-configuring mobile wireless networks to support robots on the move. In Steven Spielberg's recent blockbuster, "Minority Report," a swarm of robotic spiders marches through a tenement in search of our hero, who lies hidden in a bathtub. Working together, the robots systematically search the building until they track down their target. It's all pure science fiction, straight from the mind of Philip K. Dick-but the wireless networks to support those spiders are currently in development. The U.S. Navy's Autonomous Intelligent Network and Systems (AINS) initiative is working towards the battlefield deployment of swarms of thousands of unmanned aerial vehicles (UAVs) and unmanned ground vehicles (UGVs), capable of engaging in everything from surveillance to actual combat. They're unlikely to look much like Spielberg's robot spiders, but they'll be similar in many other ways. Behind the AINS initiative is UCLA's Multimedia Intelligent Network of Unattended Mobile Agents (MinuteMan) Project, funded by the Office of Naval Research. The five-year, $11 million project is focused on developing protocols and algorithms to support a mobile, flexible "Internet in the Sky," a wireless network of UAVs able to reconfigure itself autonomously on the move. The network is being developed for use in battlefield situations, but there are a wide variety of potential commercial applications for this kind of highly flexible solution. From self-configuring wireless networks to adaptive mobile video transmission, there's a lot going on in MinuteMan that's worth watching. Robots with Brains Dr. Allen Moshfegh of the Office of Naval Research, who heads the AINS initiative, explains that the objective is to provide a wireless infrastructure on the fly using UAVs and UGVs. "The goal is to be able to spontaneously form networks in an evolving environment," he said. "We'd like to network our infrastructure in an intelligent way, so we don't need a preexisting infrastructure to get things going." It's the intelligence, or independence, of that network that's the central challenge of the MinuteMan Project. To maintain wireless connectivity between thousands of unmanned platforms, some moving as fast as 700 miles per hour, the network has to be constantly reconfiguring itself. Dr. Mario Gerla, who heads the project at UCLA, points out that the UAVs, therefore, have to be essentially autonomous. "It could never work to have a commander watching all 10,000 assets on a screen and making a decision about each one," Gerla said. "Suppose a formation of UAVs is flying over rugged terrain and the front nodes see an obstacle. They start flying up, they tell the nodes in the back, and the entire swarm moves around it. You couldn't do that from a command post hundreds of miles away." The difference between this and conventional systems, Gerla explains, is that there's no man in the loop-which means the UAVs have to be able to determine their own hierarchy. "For routing, it is important to have some kind of leader," he said. "And the important thing in our design is that we want to make the hierarchy completely flexible." The idea is to decentralize all decision-making in order to keep the nodes as autonomous as possible, and to eliminate any single point of failure. When the UAVs move in clusters, they 'elect' a leader, which can be automatically replaced if lost. "The leader will be responsible for maintaining connectivity and routing, but if that particular leader is shot down, another one will be immediately elected," Gerla said. Antennas that Move In developing a self-configuring network of UAVs, Gerla says, additional challenges include scalability and mobility. The hierarchies discussed above improve scalability by focusing responsibility on a smaller number of group 'leaders,' but those groups have to be able to change on an almost continual basis in order to support the degree of mobility the MinuteMan Project is seeking. In order to work in such a mobile environment, the UCLA researchers are developing new protocols and addressing schemes. "As the node moves from cluster to cluster, the addressing remains seamless," Moshfegh said. "Every node is uniquely identified as a contributing member of this mobile wireless network." He adds that bandwidth can be increased or decreased, as needed, by simply moving nodes around. "We're designing this dynamic mobile backbone to provide the right amount of bandwidth for a given task," Moshfegh said. "If the existing cluster does not have sufficient bandwidth, we may bring in other UAVs, or reposition them, to supply more bandwidth." On the other hand, Gerla notes that it's also crucial to make the best possible use of the bandwidth available. "We're designing very efficient video encoders to work on this architecture," he said. "If the connection quality degrades because of enemy jamming, you can still pipe something back, even at a much slower rate." The aim is to give priority to mission-critical needs. If a soldier urgently needs more bandwidth to transmit or receive video in the field, the network has to be able to reconfigure automatically to supply the bandwidth required. "A soldier should be able to get the right set of network assets configured in a way that allows him to do his job in a safe manner," Moshfegh said. "We can't tolerate delay." A Clear Signal Finally, Gerla points out, an additional challenge appears when thousands of drones are transmitting video at once. "You'll need to have multiple video streams piped all the way back to the commander, which is something that currently cannot be done," he said. "Nobody has ever tried to maintain a networked swarm with many streams." Key to solving that problem, Moshfegh says, will be the use of Multiple Input, Multiple Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) technology. "It's a radio concept that allows for very clear communications with very little noise," Moshfegh said. "It will really enhance our capability to operate in urban environments, in caves, and things of that nature." Yankee Group analyst John Jackson suggests that a program like MinuteMan is the ideal place to develop new-and expensive-technologies like OFDM. "It's a technology that's in a very, very early stage, and it will amount to 4G," he said. "It's just not commercially viable yet. The testing that needs to be done to get it working has not been completed, and nobody can afford it right now." And what makes MinuteMan different from many other projects, Moshfegh says, is that the researchers actually have to prove that their ideas will work. "We're not just publishing papers," he said. "The protocols have got to be validated before we go to the next phase of the program. They have to demonstrate them using the wireless networking infrastructure they've developed." In order to do so, the researchers are developing a hybrid simulation test bed which will allow them to test thousands of virtual nodes. "The plan is to have 20 or so nodes connected to the simulator," Gerla said. "While we're running those nodes in real life, the remaining thousands of nodes will be simulated through a gateway, so we can evaluate the performance of the entire system in a very realistic way." Into Civilian Life None of this technology, however, is limited to military applications: Gerla contends that any network this autonomous and flexible should have many uses beyond the battlefield. "I could see civilian applications in emergency recovery, like fuel spills or nuclear situations where you can't send in people or even manned vehicles," he said. Large-scale security operations in stadiums or arenas could also benefit from these capabilities. "Instead of a swarm of UAVs, you would have actual people carrying cell phones and laptops," Gerla said. "They could form a sort of clique to connect to each other and to the Internet. Once the technology is inexpensive enough, it will happen." UCLA professor John Villasenor, another member of the project team, suggests that the adaptive network technology could be applied to Wi-Fi networking as well. "One of the more interesting possible future uses for 802.11 is to support this kind of adaptive network," he said. "To the extent that we want to have ubiquitous wireless connectivity, the technologies we're developing could assist with that." Of course, it's not just a matter of deploying the network as a whole: MinuteMan is also making advances in specific technology areas. "Many of the components could be pulled out and used for commercial applications," Gerla said. "The robust video can be used for anything, including point-to-point communications: you don't have to justify it only in a thousand-node network." And Villasenor points out that the military is an excellent source for advances like these: with its unique funding and support, a project like MinuteMan is able to explore possibilities that the commercial sector can't afford to support. "A commercial 3G system with video is fairly far down the road-whereas the military has an immediate and growing need for this kind of very sophisticated imagery," he said __________________________________________________ Do you Yahoo!? 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