Qualcomm: Predicting real-world performance of 5G NR mobile networks and devices

Alejandro Holcman

Senior Vice President, Engineering Services Group, Qualcomm Technologies, Inc.

Last week, the mobile industry gathered in Barcelona, Spain, at Mobile World Congress (MWC) 2018, to showcase the latest innovations in mobile technology. Over the last few years, 5G has quickly evolved from visionary statements in keynote presentations, to real demonstrations of 5G technologies and the opportunities they can bring. And at MWC this past week, we witnessed 5G on the brink of becoming a commercial reality. And once again, Qualcomm is right at the forefront, leading the way to commercial 5G mobile network and device launches that we expect to be on full display at MWC 2019 

At MWC 2018 last week, in collaboration with leading infrastructure vendors and global operators, we demonstrated our industry-leading 5G NR interoperability testing compliant with the 3GPP global 5G NR standard recently completed this past December. The technical advancements demonstrated in the interoperability testing are quite amazing — multi-gigabit per second data rates, single-digit millisecond latencies, advanced antenna techniques, and unparalleled levels of scalability and flexibility. This standard-compliant interoperability testing serves as a significant milestone on the path to over-the-air field trials later this year and commercialization starting in 2019.

But how will 5G NR enhanced mobile broadband perform in the real world? This is a question we have been receiving quite a bit over the last year. As mobile operators plan for 5G NR mobile network launches, they want to get insights into the real-world capacity benefits of 5G NR as they overlay this new technology on their existing LTE networks and cell sites. In addition, mobile device manufacturers, app developers, and cloud platform providers want to understand the real-world performance that 5G NR mobile devices will bring, so they can begin innovating the next-generation of amazing mobile user experiences.

Answering these questions cannot fully wait for large-scale trials set for later this year to prepare for 2019. And that is why, last week, we introduced our 5G NR Network Capacity and User Experience Simulation platform — the industry’s first detailed simulation platform of 5G NR mobile networks and devices. Building upon Qualcomm Technologies’ unique capabilities to accurately model and simulate cellular systems, along with our global network experience and ecosystem collaborations, the simulation platform delivers quantitative insights to the 5G ecosystem on the expected real-world performance and user experience of 5G and Gigabit LTE devices, operating in Non-Standalone (NSA) multimode 4G/5G NR networks. At MWC Barcelona, the simulation platform was on full display in Qualcomm’s booth (Figure 1), showcasing two simulation studies conducted in Frankfurt, Germany and San Francisco, USA. The results from the 5G Network Capacity Simulation lend credence to the promise of 5G, with expected real-world performance that is substantially better than what is currently possible with 4G. Let’s take a closer look at the results.

Frankfurt 5G NR Sub-6 GHz simulation

The first simulation modeled a NSA 5G NR network in Frankfurt, Germany (Figure 2), utilizing existing macro and small cell base stations with the new 5G NR cell sites co-located with existing LTE cell sites. The simulations were based on modeling of the physical base stations and their RF capabilities, including Massive MIMO capability for 5G NR sub-6 GHz utilizing up to 256 antennas, while the LTE-only traffic was modeled utilizing four antennas at the base station. The propagation between the base stations and the devices was modeled based on detailed 3D urban macrocell and urban microcell models to accurately depict real-world performance, including path loss, shadowing, diffraction, building penetration loss, interference, and more.

The Frankfurt 5G NR network operates on 100 MHz of 3.5 GHz spectrum, with an underlying Gigabit LTE network operating across five LTE spectrum bands. The mixture of devices, capabilities of devices, and spectrum bands/bandwidths utilized by the devices were all chosen based on anticipated commercial deployments for LTE-only and NSA 5G NR networks in the 2019 timeframe. As in Figure 2, over 13,000 active user devices, of various capabilities, were randomly distributed across the network with approximately 50 percent of the users indoor and 50 percent of the users outdoor. Across the existing 11 cell sites in Frankfurt, the simulation study showcased a downlink capacity increase of nearly 5x when migrating from an LTE-only network, with a mix of LTE devices of various capabilities, to a 5G NR network with multi-mode 5G NR devices and an increased mix of advanced Gigabit LTE devices. This simulation also yielded compelling evidence of the benefits of Massive MIMO technology to deliver significantly lower cost-per-bit, with median spectral efficiency increases of up to 4x on 3.5 GHz spectrum. Furthermore, the simulation showcased the positive impact of 5G NR on 4G LTE devices, as the median burst rate for a 4G device increased nearly 2x from the LTE-only network to the LTE + 5G NR network.

These are great results, but as I stated earlier, the simulation platform goes far beyond just modeling network capacity gains. To deliver device manufacturers, app developers, and OTT cloud providers insight to real-world user performance on 5G mobile devices, the simulation platform provides the ability to get device-level Key Performance Indicators (KPIs) and the resulting impact on consumer user experience for each of the 13,000+ active devices in the network. The simulation models different traffic patterns for each device in the network based on a representative mixture of mobile applications including browsing (bursty traffic, e.g., web, social network feeds), cloud storage downloading of a 3GB high-definition movie, and adaptive bitrate 360-degree video streaming (8K resolution, 120 fps framerate). An example for a 5G NR device in the Frankfurt network is shown below in Figure 3. The device is achieving a DL data rate of 369 Mbps, which enables 100% video playback at the max 8K, 120 fps video bitrate as shown in the bitrate distribution chart on the right. Figure 3 also showcases the device-level KPIs the simulation platform displays, including data rate, signal quality, spectral efficiency, MIMO rank, and spectrum bands/bandwidths.

To enable quick comparison of the expected user experiences with 5G NR-capable devices versus LTE-only devices, the simulation platform provides the ability to easily compare the 10^th percentile (cell-edge/challenging signal conditions) 50^thpercentile (median user), or 90^th percentile (ideal signal conditions) devices across the network for a chosen traffic pattern. Figure 4 showcases a comparison of the 10^th percentile LTE Cat 9 device (common LTE device today) and the 10^th percentile 5G NR sub-6 GHz device for downloading a 3GB movie from the cloud. The comparison showcases an over 5x increase in user experience.

The results in Figure 4 also showcases the benefit of 5G NR to deliver fast speeds even in the most challenging signal conditions (100 Mbps at 10^th percentile shown). Even more important than the multi-Gbps peak data rates, this reliable, consistent performance is expected to enable mobile app developers and OTT cloud providers to innovate the consumer experience much further than what is possible with 4G LTE devices today.

The simulation platform also delivers the ability to compare KPIs across all the device categories in the network for a given traffic type (browse, download, or stream) and device ranking (options for 10^th, 50^th, or 90^th percentile user). Figure 5 showcases the KPI comparison for browsing traffic type and 90^th percentile device ranking. The overall performance metrics (throughput, latency) clearly show the evolution of LTE from early Category 4 devices, introduced back in the early 2010’s, all the way through the latest Gigabit LTE Category 20 devices with first commercial devices expected by the end of 2018. The continued evolution of 4G LTE technology, being led by Qualcomm, is essential as 5G NR networks get phased in. Gigabit LTE will deliver an anchor to the 5G enhanced mobile experience, as 5G NR network coverage will not be everywhere on Day 1. These Gigabit LTE advancements ensure consumers do not suffer from a significant falloff in user experience as they move in and out of 5G coverage.

Beyond the evolution of LTE, the KPIs also showcase the big leap forward in both performance and efficiency that 5G NR brings to today’s networks. The fiber-like data speeds, low latencies for real-time interactivity, and more consistent performance throughout the network open new opportunities for the entire mobile ecosystem. When combined with the massive 5G NR capacity gains for unlimited data plans, we start to see the potential for 5G networks to shift consumer behavior. If with 5G NR, we can consistently enjoy data speeds over 50 Mbps with truly unlimited data plans, this can dramatically change the way we consume/share media and entertainment from fixed to mobile — potentially drastically increasing a trend that is already happening today.

Furthermore, these levels of performance are essential to the next generation of mobile experiences, including immersive VR/AR/XR video streaming and connected cloud computing. At these extreme speeds and latencies, we can envision a world in which the computation on our mobile devices is augmented with instantaneous, on-demand access to the computation power of the cloud. Mobile devices can have access to virtually unlimited storage as access times to the cloud rival local device memory. This has the potential to go far beyond just faster downloads and streaming to our devices, redefining the capabilities and experiences possible in a mobile, battery-powered, form-factor-limited device.

San Francisco 5G NR mmWave simulation

The San Francisco simulation modeled a hypothetical NSA 5G NR network in San Francisco, California, operating at 28 GHz mmWave spectrum (8x 100 MHz bandwidth), with an underlying Gigabit LTE network operating across four licensed LTE spectrum bands plus License Assisted Access (LAA) bands. Like the Frankfurt simulation, existing cell site locations in San Francisco were used, where 5G NR cell sites are co-located with actual, existing LTE sites. Across the existing 13 cell sites in San Francisco, the simulation study showcased a downlink capacity increase of over 5x when migrating from an LTE-only network, with a mix of LTE devices of various capabilities, to a 5G NR network with multi-mode 5G NR devices and an increased mix of advanced Gigabit LTE devices (Figure 6).

Historically, the large bandwidths available at these high frequencies have not been accessible for mobile communications due to the increased propagation loss, susceptibility to blockage (e.g. hand, head, body, foliage, building penetration), and RFIC complexity and power-efficiency. At Qualcomm, we have been working for many years on the key design elements necessary to harness mmWave bands for usage in mobile broadband communication systems — proving to both ourselves and the industry what is feasible and what needs more work.

The 5G NR mmWave simulation in San Francisco makes use of the extensive over-the-air testing and channel measurements conducted by Qualcomm Technologies at these high-frequencies. It also builds upon the extensive network coverage simulation studies we conducted in numerous global cities, including San Francisco. The results of the coverage simulation studies show that significant outdoor downlink coverage is possible when co-siting 5G NR mmWave with existing 4G LTE macro and small cell sites (Figure 7). The positive results show that mobile deployments in urban-areas based on existing LTE cell sites is feasible, especially when considering the tight-interworking of 5G NR with 4G LTE. And although mmWave outdoor-to-indoor coverage for mobile is not feasible, the outdoor mmWave coverage will significantly free up resources in the spectrum bands below 6 GHz for better serving indoor users with outdoor cell sites. In addition, outdoor mmWave coverage can be complemented with targeted indoor mmWave deployments (e.g., Las Vegas Convention as shown in Figure 7).

The San Francisco simulation provides a glimpse into the impact of the significantly increased capacity afforded by 800 MHz of additional mmWave spectrum on a real-world user experience. Key findings include:

• Burst download speeds exceeding 3 Gbps and download latencies as low as few milliseconds (Figure 8)
• Browsing download speeds increasing from 71 Mbps for the median 4G user to 1.4 Gbps for the median 5G user in mmWave coverage, a gain of approximately 20x
• Approximately 23x faster responsiveness, with median browsing download latency reduced from 115ms to 4.9ms
• File download speeds of more than 186 Mbps for 90 percent of 5G users, compared to 10 Mbps for LTE, a gain of over 18x
• Median streaming video quality increasing from 2K/30 FPS/8-bit color for LTE users to 8K/120 FPS/10-bit color and beyond for 5G users

From simulation to commercial network and device launches

The results from the 5G Network Capacity and User Experience Simulation lend credence to the promise of 5G, with expected real-world performance that is substantially better than what is currently possible with 4G across multiple metrics. The findings also illustrate that these emerging 5G networks will have the capacity and performance to support a whole host of new services and experiences beyond the traditional categories of browsing, downloading, and streaming. With 18 global operators and 20 leading device makers selecting the Qualcomm Snapdragon X50 5G modem for the first wave of 5G network trials and consumer devices, the stage is set for these incredible 5G user experiences to come to user’s hands in the first half of 2019.

To learn more, please visit our 5G MWC 2018 website where you can watch a demonstration video of the 5G Network Capacity and User Experience Simulation, as well as explore a virtual showroom where you will find all of our other 5G demos showcased at MWC18 in Barcelona.