Aug. 28, 2011 Thanks to numerous sensors, smartphones make it easy for their owners to organize certain parts of their lives. However, that is just the beginning. Darmstadt researchers envision entire "smart" cities, where all devices present within municipal areas are intelligently linked to one another.
Computer scientists, electrical and computer engineers, and mathematicians at the TU Darmstadt and the University of Kassel have joined forces and are working on implementing that vision under their "Cocoon" project. The backbone of a "smart" city is a communications network consisting of sensors that receive streams of data, or signals, analyze them, and transmit them onward. Such sensors thus act as both receivers and transmitters, i.e., represent transceivers. The networked communications involved operates wirelessly via radio links, and yields added values to all participants by analyzing the input data involved. For example, the "Smart Home" control system already on the market allows networking all sorts of devices and automatically regulating them to suit demands, thereby allegedly yielding energy savings of as much as fifteen percent.
"Smart Home" might soon be followed by "Smart Hospital," "Smart Industry," or "Smart Farm," and even "smart" systems tailored to suit mobile networks are feasible. Traffic jams may be avoided by, for example, car-to-car or car-to-environment (car-to-X) communications. Health-service systems might also benefit from mobile, sensor communications whenever patients need to be kept supplied with information tailored to suit their healthcare needs while underway. Furthermore, sensors on their bodies could assess the status of their health and automatically transmit calls for emergency medical assistance, whenever necessary.
"Smart" and mobile, thanks to beam forming
The researchers regard the ceaseless travels of sensors on mobile systems and their frequent entries into/exits from instrumented areas as the major hurdle to be overcome in implementing their vision of "smart" cities. Sensor-aided devices will have to deal with that by responding to subtle changes in their environments and flexibly, efficiently, regulating the qualities of received and transmitted signals. Beam forming, a field in which the TU Darmstadt's Institute for Communications Technology is active, should help out there. On that subject, Prof. Rolf Jakoby of the TU Darmstadt's Electrical Engineering and Information Technology Dept. remarked that, "Current types of antennae radiate omnidirectionally, like light bulbs. We intend to create conditions, under which antennae will, in the future, behave like spotlights that, once they have located a sought device, will track it, while suppressing interference by stray electromagnetic radiation from other devices that might also be present in the area."
Such antennae, along with transceivers equipped with them, are thus reconfigurable, i.e., adjustable to suit ambient conditions by means of onboard electronic circuitry or remote controls. Working in collaboration with an industrial partner, Jakoby has already equipped terrestrial digital-television (TDTV) transmitters with reconfigurable amplifiers that allow amplifying transmitted-signal levels by as much as ten percent. He added that, "If all of Germany's TDTV‑transmitters were equipped with such amplifiers, we could shut down one nuclear power plant."
Frequency bands are a scarce resource
Reconfigurable devices also make much more efficient use of a scarce resource, frequency bands. Users have thus far been allocated rigorously defined frequency bands, where only fifteen to twenty percent of the capacities of even the more popular ones have been allocated. Beam forming might allow making more efficient use of them. Jakoby noted that, "This is an area that we are still taking a close look at, but we are well along the way toward understanding the system better." However, only a few uses of beam forming have emerged to date, since currently available systems are too expensive for mass applications.
Small, model networks are targeted
Yet another fundamental problem remains to be solved before "smart" cities may become realities. Sensor communications requires the cooperation of all devices involved, across all communications protocols, such as "Bluetooth," and across all networks, such as the European Global System for Mobile Communications (GSM) mobile-telephone network or wireless local-area networks (WLAN), which cannot be achieved with current devices, communications protocols, and networks. Jakoby explained that, "Converting all devices to a common communications protocol is infeasible, which is why we are seeking a new protocol that would be superimposed upon everything and allow them to communicate via several protocols." Transmission channels would also have to be capable of handling a massive flood of data, since, as Prof. Abdelhak Zoubir of the TU Darmstadt's Electrical Engineering and Information Technology Dept., the "Cocoon" project's coordinator, put it, "A "smart" Darmstadt alone would surely involve a million sensors communicating with one another via satellites, mobile telephones, computers, and all of the other types of devices that we already have available. Furthermore, since a single, mobile sensor is readily capable of generating several hundred Megabytes of data annually, new models for handling the communications of millions of such sensors that will more densely compress data in order to provide for error-free communications will be needed. Several hurdles will thus have to be overcome before "smart" cities become reality. Nevertheless, the scientists working on the "Cocoon" project are convinced that they will be able to simulate a "smart" city incorporating various types of devices employing early versions of small, model networks.
Over the next three years, scientists at the TU Darmstadt will be receiving a total of 4.5 million Euros from the State of Hesse's Offensive for Developing Scientific-Economic Excellence for their researches in conjunction with their "Cocoon -- Cooperative Sensor Communications" project.
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