DEL MAR, Calif.–5G will be supported by four “pillars” as the industry seeks to transition to the next generation of wireless technology, according to Andreas Roessler, technology manager at test company Rohde & Schwarz.
Roessler, speaking at the 5G Innovation Summit, said that those four pillars of 5G include:
–Moving into new spectrum at millimeter wave. This expansion into higher frequencies is driven both by the large amounts of available spectrum at mmwave, and the fact that much of the spectrum at lower frequencies is already in use. Operation at mmwave is seen as one of the major challenges of 5G, however, due to the propagation characteristics of the spectrum, which can be easily blocked simply by the human body or foliage. Roessler noted that a significant number of trials involve the use of 3.5 GHz for the first versions of 5G networks, rather than mmwave — although 28 GHz and 39 GHz are being explored by operators Verizon and AT&T.
-Massive multiple-input-multiple-output and beamforming. Massive MIMO and the ability to form narrow directional beams are essential to leveraging millimeter wave, Roessler said, in order to combat some of the inherent weaknesses in mmwave spectrum. However, he noted, this poses significant challenges to testing for 5G, as antennas become very small in mmwave and are positioned in arrays with many elements. At that point, the traditional testing method of connecting to each element to assess its characteristics is basically impossible, so over-the-air testing and the use of automated chambers which can take rapid measurements from multiple positions are expected to become the dominant testing strategy.
–Multi-connectivity. This concept of utilizing multiple frequency bands and/or technologies is already being introduced in an LTE context, Roessler said, as carrier aggregation extends into the use of LTE in unlicensed frequencies at 5 GHz or License-Assisted Access. LAA has been introduced by a number of carriers, and independent testing of the technology was discussed by Emil Olbrich of Primeline. Olbrich — who also works with Signals Research Group — said that at one operator’s small cell site, testing by SRG showed that devices with LAA support provided a consistently higher data rate with download speeds three times faster than devices without LAA and other features such as 256 QAM modulation and 4×4 MIMO capabilities. SRG found in its testing that LAA was available to the device about 75% of the time to support a better user experience.
Multi-connectivity will be key to the first version of 5G that emerges, Roessler said, since most operators are planning to move to a “non-standalone” version of 5G that leverages LTE as a master technology with controlling functionality and 5G as a secondary technology. Eventually, he added, networks will transition to the point where 5G networks handle control functions as a standalone network.
–Network flexibility. This covers network technologies including software-defined networking and network function virtualization, and network slicing to support different types of applications. This should open up new opportunities for network operators to address those applications such as ultra-high-definition video services, virtual seats within entertainment venues, or industrial internet of things use cases, Roessler said, noting that applications to this point have typically run over operator networks without operators having much opportunity to gain new revenues.
The Third Generation Partnership Project, Roessler noted, met in Reno, Nev. last week to work on finalizing the first official 5G standard, which is expected to be released later this month.
