5.9: 6G, Sixth Generation Radio

Sixth generation radio will operate in the \(95\text{ GHz}\) to \(275\text{ GHz}\) range, and will provide data rates of \(100\text{ Gbit/s}\) [38]. While 5G hopes to provide these data rates at \(60\text{ GHz}\) this may not come to pass as the required spectral efficiency of \(14\text{ bits/s/Hz}\) and requires \(60\text{ GHz}\) hardware with very high dynamic range and this is unlikely to be available for some time. With 6G these data rates will be possible with much lower-order modulation and hence reduced demands on hardware Regulatory bodies have allocated several bands in this range. In the USA these bands are \(116–123\text{ GHz},\: 174.8–182\text{ GHz},\: 185– 190\text{ GHz},\) and \(244–246\text{ GHz}\) for a total of \(21\text{ GHz}\) of spectrum. Atmospheric losses can be large at these frequencies but, except for a peak of absorption around \(140\text{ GHz}\), this is more than compensated by the pencil-like beams generated by many-element phased array antennas possible at these high frequencies. The \(100+\text{ GHz}\) frequencies have wavelengths of \(3\text{ mm}\) or less enabling functionality not available at \(60\text{ GHz}\) and below. These include precise positioning with millimeter resolution, near visual-quality imaging through fog and clouds, wireless cognition (off-loading large data sets from a mobile units for fixed computation), and unique sensing modalities by exploiting the many molecular resonances that occur above \(100\text{ GHz}\). The overwhelming challenge is the development of physical hardware and the development of array processing technologies [38].