With the advent of 5G, cellular networking is changing more than the smartphone experience; it’s opening up new use cases for every sector of the economy including automotive, smart factories, and telemedicine. As we pointed out in our previous post, these advances simply can’t happen without significant improvements in the accuracy, speed, and availability of positioning information.
In our , we reviewed positioning technology as it relates to cellular networks. That technology goes far beyond “just GPS.” To achieve the pinpoint accuracy required by new use cases, we’ve begun combining multiple technologies—A-GNSS (Assisted GNSS), ECID and OTDOA, and Wi-Fi—to form a “hybrid” positioning system that provides accurate location information both indoors and outdoors.
Replace 4G with 5G? Not so fast.
Now let’s take a look at another issue of significance to emerging positioning solutions: the evolution from 4G to 5G. 5G offers significant enhancements to current 4G positioning techniques, as well as completely new ones such as using beamforming information to determine vertical position. But we won’t move to 5G in a single leap. 5G devices will use 4G LTE bands and protocols for emergency calling location information.
4G LTE cellular, GNSS, and hybrid positioning techniques are in the ten-to-dozens of meter accuracy range, with Time-To-First-Fix (TTFF) and update latency in the seconds to tens-of-seconds range. These ranges are insufficient for needs such as in-building asset management or unmanned aerial vehicles.
Enhancing 4G location
To exceed current-day performance and meet the evolving needs for more stringent accuracy and speed, many innovative technologies are being developed including Advanced Wi-Fi technology (802.11mc) that introduces Fine Time Measurement (FTM) for accuracy within 1-2 meters; onboard inertial, magnetic, and barometric sensors; GNSS chipsets with L5 band support and the ability to scan multiple GNSS frequencies simultaneously; and terrestrial beacon systems with indoor-penetrating radios.
What 5G will bring to positioning
5G technology also has many new assets to bring to the table:
5G is a wideband technology, and higher bandwidth enables more positioning information (positioning reference signals, or PRS) to be exchanged between the device and the gNodeB base station.
5G brings massive MIMO and beamforming technologies to the mix.
Higher frequencies allow for higher resolution of beamforming.
Small cells, picocells and femtocells provide densification to.
Protocol upgrades handle all these new sources of positioning data.
Timeline for 5G location technologies
Moving from today’s positioning technologies to the incorporation of 5G enhancements will
In the first phase, 5G handsets and devices will exclusively employ 4G LTE positioning technologies. In the second phase, location information is exchanged between the user equipment and base station natively over 5G. Some of the performance improvements that 5G enables may be included. In the third phase, enhancements to positioning derived from new 5G assets (higher bandwidth, beamforming, higher frequencies, and densification, as described above) are rolled in.
5G offers significant enhancements to current 4G positioning techniques, as well as completely new ones such as using beamforming information to determine vertical position.
5G location test challenges
Along with the many benefits we just outlined, phased movement from 4G to 5G will bring challenges. As just one example, it’s been proven that 5G NR can potentially disrupt the LTE positioning designs that had been serving 4G devices perfectly well before.
Therefore, we must perform accurate testing of these new 5G technologies to ensure the location performance of new 5G devices and services. It’s also critical in the near term to test 4G positioning performance within 5G devices to ensure there’s no disruption of accuracy.
Network providers and device manufacturers are already working to understand the potential challenges and design test methodologies to ensure that location-based systems work as intended.
We’ve seen this before
Spirent has been at the center of GNSS testing for more than 30 years. So, when it comes to phased rollouts and assuring complex systems that blend legacy and new technologies, we've seen it before. A similar situation occurred as 4G began to roll out. Handsets were dual-mode 3G/4G and used 3G exclusively for E911 emergency calls for several years. The initial dual-mode phones that used 3G for E911 suffered a variety of location performance issues that were discovered during testing.
Spirent saw quite a few 3G/4G devices where the new LTE bands interfered with the devices’ GPS satellite positioning receivers. It was also common to see 3G/4G devices that failed to perform 3G location positioning accurately due to protocol or processing prioritization issues.
5G is rushing towards us, bringing welcome improvements in location and positioning accuracy for our mobile devices. But the transition will be complex and brings its own new challenges. Spirent’s (LTS) offers proven, cutting- edge testing solutions that can make the transition simpler and smoother. We’re helping assure that device designers and mobile operators fulfill their promise to their customers of high quality, hiccup-free service—even as technologies and networks shift, blend, and evolve in new and possibly unpredicted ways.
For our complete, in-depth discussion of 5G and location technologies with more potential issues and tips to look out for, read the white paper,