Beyond smart phones: Sensor network to make 'smart cities' envisioned

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.