Are We Ready for 6G?

Apart from simply being an evolution of the 5G technology, 6G is actually a transformation of cellular technology. Just like 4G introduced us to the mobile Internet, and 5G helped to expand cellular communications beyond the customary cell phones, with 6G the world will be taken to newer heights of mobile communications, beyond the traditional devices and applications for cellular communication.

6G devices operate at sub-terahertz or sub-THz frequencies with wide bandwidths. That means 6G opens up the possibility of transfers of massive amounts of information compared to those under use by 4G and even 5G. Therefore, 6G frequencies and bandwidth will provide applications with immersive holograms with VR or Virtual Reality and AR or Augmented Reality.

However, working at sub-THz frequencies means newer research and understanding of material properties, antennas, and semiconductors, along with newer DSP or Digital Signal Processing technologies. Researchers are working with materials like SiGe or Silicon Germanium and InP or Indium Phosphide to develop highly integrated high-power devices. Many commercial entities, universities, and defense industries have been going ahead with research on using these compound semiconductor technologies for years. Their goal is to improve the upper limits of frequency and performance in areas like linearity and noise. It is essential for the industry to understand the system performance before they can commercialize these materials for use in 6G systems.

As the demand increases for higher data rates, the industry moves towards higher frequencies, because of the higher tranches of bandwidth availability. This has been a continuous trend across all generations of cellular technology. For instance, 5G has expanded into bands between 24 and 71 GHz. 6G research is also likely to take the same path. For instance, commercial systems are already using bands from FR2 or Frequency Range 2. The demand for high data rates is at the root of all this trend-setting.

6G devices working at sub-THz frequencies require generating adequate amounts of power for overcoming higher propagation losses and semiconductor limits. Their antenna design must integrate with both the receiver and the transmitter. The receiver design must offer the lowest possible noise figures. The entire available band must have high-fidelity modulation. Digital signal processing must be high-speed to accommodate high data rates in wide bandwidth swathes.

While focussing on the above aspects, it is also necessary to overcome the physical barriers of material properties while reducing noise in the system. This requires the development of newer technologies that not only work at high frequencies, but also provide digitization, test, and measurements at those frequencies. For instance, handling research at sub-THz systems requires wide bandwidth test instruments.

A 6G working system may require characterization of the channel through which its signals propagate. This is because the sub-THz region for 6G has novel frequency bands for effective communications. Such channel-sounding characterization is necessary to create a mathematical model of the radio channel that can encompass intercity reflectors such as buildings, cars, and people. This helps to design the rest of the transceiver technology. It also includes modulation and encoding schemes for forward error correction and overcoming channel variations.