With the aid of multiple antenna technology, ETH Zurich researchers have succeeded in quadrupling the existing transmission rate of conventional networks from 54 Mbps to 216 Mbps. The successful tests involving several users were conducted within the framework of a research project funded by the European Union.
According to the communication theory, only a limited amount of data can be transmitted within a given bandwidth for wireless communication. Thanks to so-called MIMO technology, which stands for "multiple input multiple output", it is possible for several transceivers to communicate with each other on the same bandwidth at the same time. Transceivers have several antennas.
"It is as if several people are communicating with several other people", explains Helmut Bölcskei, professor at the Communications Technology Laboratory at ETH Zurich. "At face value, it just seems like an incomprehensible babble. If the listeners skillfully combine the hubbub, however, they can filter out the original messages." In terms of wireless communication, this means you can transfer far more information than with existing procedures.
ETH Zurich researchers had already furnished proof that MIMO technology works in a similar test facility three years ago—albeit with only one user. However, until recently it was still unclear as to whether and how the increase in capacity could be implemented in complex networks with several users. For the first time, the Zurich-based researchers were able to demonstrate that the principle of multiple antenna systems is actually feasible for use in complex wireless networks both theoretically and using their test facility. In doing so, they succeeded in constructing a compact multi-user system, currently with three stations in a bench scale, where every station transmits or receives via four antennae. This meant that the utilization of the frequency range for each of the three users could be up to four times higher than with present-day WLAN networks.
