Exhibit Communication Technology

Various institutes of the Faculty of Electrical Engineering and Information Technology participated in the joint anniversary exhibition of RWTH Aachen University and of the City of Aachen at the Centre Charlemagne. This exhibition provides insights into the history and evolution of RWTH Aachen University, which was founded on October 10, 1870 as “Königliche Rheinisch-Westphälische Polytechnische Schule” (Royal Rhenish-Westphalian Polytechnic School), and allows to discover the most exciting pieces of research covering all the relevant areas of the past 150 years. Our exhibit on the subject of communications technology comprises a brief history of technical developments in communications and contributions from RWTH Aachen University. It provides two exciting demonstrators of the Institute of Communications Engineering (video) and the Institute of Communication Systems (audio). This exhibit was kindly supported by Head acoustics, Ericsson Eurolab and aixxess.

Information and communication technology (ICT) influences all areas of everyday life. Without ICT, telephoning, watching TV, surfing on the Internet or autonomous driving would not be possible. ICT is the core of digitization and a driving force behind far-reaching changes in the economy and in the society.

This exhibit shows by the example of telephony the development of the underlying technologies from electromechanics and analog technology to today's digital technology. Whereas in the electromechanical and analog phases, different applications required correspondingly specialized devices and networks, progressive digitization is merging devices, networks and services into new multimedia communications technology. A smartphone supports not only voice telephony, but also a wide range of data applications such as e-mail, video conferencing, navigation, music and video streaming.

RWTH institutes of the Faculty of Electrical Engineering and Information Technology (www.elektrotechnik.rwth-aachen.de) have contributed significantly to the ICT development and the definition of global communication standards from the early beginnings until today. The exhibit shows representative examples of microelectronics, fixed and wireless networks, terminal devices and the compression of audio and video signals.

The video demonstrator compares the capabilities of three generations of video compression standards from the last twenty years. During this development, the data rate necessary for good video quality could be further reduced, such that many applications which are common today became possible:

• In 2003, MPEG-4 "Advanced Video Coding" (AVC, H.264) brought the breakthrough for High Definition (HD) video, e.g. for digital broadcast or Blu-ray storage. It is also commonly used for recording video by smartphones today.
• MPEG-H "High Efficiency Video Coding" (HEVC, H.265) from 2013 achieved the same quality as AVC at half the data rate and allowed the introduction of Ultra HD (UHD, 4K), now commonly used for broadcast and streaming video in such high resolution.
• With MPEG-I "Versatile Video Coding" (VVC, H.266) from 2020, not only the compression but also the versatility has been improved. Videos with very high resolution (8K and higher), larger brightness range (High Dynamic Range, HDR), or 360° videos can be compressed even more efficiently.

Use the touch screen monitor to compare any two of these compression methods against each other. Can you spot any differences in quality? You can also use the slider to view an area of the video processed by either the first or the second method.

The Institute of Communications Engineering at RWTH contributed to all these developments. Prof. Ohm chaired the responsible international standardization committees and received the „Emmy Engineering Award“, which is also on display

The audio demonstrator guides you through a short journey through the evolution of digital speech transmission. For many years after the invention of telephony, the speech quality has remained largely unchanged. The limited speech quality is mainly determined by the restricted frequency range going from 300 Hz to 3400 Hz, while the human hearing range is six times as wide, ranging from 20 Hz to 20000 Hz.

Meanwhile, wideband transmission, capturing the frequency range from 50 Hz to 7,000 Hz, yields significantly improved speech quality and intelligibility. Compared to conventional telephony, voices no longer sound muffled but crisper.

Current research aims at binaural or spatial telephony. Here, the listener does not only perceive the voice of the distant speaker, but can also perceive the soundscape surrounding the far-end speaker. Listening now feels just like being in the same place. This immersion into the far-end scene is achieved by binaural transmission of two audio signals separately processed for the left and right ear. That’s why this demonstrator is equipped with headphones. Simply put them on and go on a journey through time with your ears pricked up!