New world record in digital radio transmission

Spectral efficiency of 10 bit / s / Hz at 60 GHz experimentally proven

For experts a picture with significant meaning: The so called constellation diagram of a radio signal modulated with 1024 QAM after the radio transmission.

Scientists of the Center for Semiconductor and Optoelectronics have made a new breakthrough in radio data transmission, which could simplify the rollout of future 5G mobile networks. Within the scope of the European research projects IPHOBAC-NG and RAPID5G, new technologies respectively system architectures have been developed, which enable a highly efficient radio transmission even at highest radio frequencies.

At the end of last year researchers of University of Duisburg-Essen announced a sensation together with their American and German colleagues from Corning and Finisar. Believe it or not, for the first time an overall volume of data of ten gigabit per second (10 GBit/s) was successfully transmitted by radio within a channel bandwidth of only one Gigahertz (1 GHz). Thereby a high radio frequency of 60 GHz was employed. Outstanding about these experiments is the enormous spectral efficiency of 10 Bit/s per Hz radio bandwidth that has been achieved at 60 GHz radio frequency. “We have achieved this through the development of novel so called photonic radio transmitter (CPX) and new system architectures, with which we could transmit complex modulated radio signals (1024 QAM) at a radio frequency of 60 GHz for the first time.”

The term “spectral efficiency” thereby means the number of bits per second, which can be transmitted within a certain radio bandwidth. Thus for a spectral efficiency of 1 Bit/s/Hz and a channel bandwidth of 1 GHz, data transmission of 1 GBit per second is possible. Important to note at this point is, that radio channel bandwidths are firmly prescribed by national regulation bodies. Therefore they cannot be simply exceeded by network operators in order to transmit more data in a given time. This means, that an increase of data transfer rate is directly linked to an enhancement of spectral efficiency. That this is now been achieved at a radio frequency of 60 GHz is especially important, because at lower frequencies worldwide just very small channel bandwidths of few 10 MHz may be used. Only in the 60 GHz band national regulation bodies allow the usage of a radio channel with a bandwidth of 1 GHz and more.

Still much room for improvement

Incredibly, the project manager see even much more potential for improvements. “Our next aim is the usage of even higher radio frequencies in the THz region (above 300 GHz), where we can use yet much higher radio channel frequencies. Thus we want to transmit up to 100 GBit/s over the radio”, according to Professor Andreas Stöhr of University Duisburg-Essen.

Contact: Andreas Stöhr