User experience in 5G NR networks expected in real conditions

    This year, 3GPP members have adopted the 5G NR specifications for network deployment in offline mode (SA). These specifications should provide support for new features — from network segmentation (network slicing) to greater granularity of quality of service (QoS) levels. To predict the real performance of devices with support for 5G and Gigabit LTE, working in a network with an autonomous implementation of the architecture (SA), large-scale modeling was carried out using data from operators around the world. We offer to get acquainted with the results in more detail.

    Download speed tests on 5G NR networks up to 6 GHz in Tokyo

    The 5G NR SA macro network segment model in Tokyo included 20 new 5G NR base stations that were located on the same sites as the existing LTE cells. The 5G NR network model in Tokyo operated in the 100 MHz band at 3.5 GHz, and the Gigabit LTE TDD core network in three LTE spectrum bands (3 × 20 MHz) (in Figure 1). The distribution between base stations and devices was modeled on the basis of high-resolution 3D maps of Tokyo, taking into account possible losses during signal propagation, shading, diffraction, losses during passage through buildings, interference, etc.

    In addition, the simulation included the use of various radio technologies, including Massive MIMO for 5G NR with 256 antenna elements and 4x4 MIMO for LTE TDD networks.

    The simulation used several types of traffic that mimic the use of devices in real conditions, namely, browsing, file downloads and streaming video playback. In addition, the simulation was carried out for different mixtures (mix) of end devices with different RF capabilities (smartphones of different LTE categories).

    Figure 1: Results of a 5G NR network capacity simulation in Tokyo for a range of up to 6 GHz when working offline (SA)

    More than 12,000 active user devices of various types were randomly distributed across the network, with about 50% of them being inside (indoor) and 50% outside (outdoor). The tests demonstrated an increase in network bandwidth for downlink data by about 5 times when switching from an LTE TDD network with a mixture of LTE devices from various categories to a 5G NR network using multi-mode devices supporting 5G NR and Gigabit LTE. Another significant advantage was that the median indices of spectral efficiency increased by 3 times.

    The simulation also gave an idea of ​​the real user experience of interacting with new networks. Key indicators obtained at various network loadings were used for its assessment. Measurements were performed during browsing (uneven traffic, browsing the Internet and social networks), downloading high-resolution movies (3 GB in size) from the cloud storage, as well as streaming 360-degree video (resolution 8K, 120 frames per second, adaptive bitrate).

    An example of the operation of the 5G NR device in the Tokyo network is shown in Figure 2. The maximum download speed reached 357 Mbps, which made it possible to transmit and play lossless video in 8K resolution at 120 fps (the bitrate distribution graph is in the right part of the figure). Also shown in Figure 2 are the main indicators obtained during the simulation, including data transfer rate, signal quality, spectral efficiency, MIMO rank and frequency spectrum.

    Figure 2: Key indicators for streaming video using 5G NR networks in the range up to 6 GHz in offline mode (SA)

    Another simulation allowed us to compare how devices in the network transmit data under different signal quality conditions - in 10th (weak signal / work "at the cell edge"), 50th (average signal quality) and 90th percentiles (ideal conditions) .

    Brief results are as follows (see Figure 3):

    • More than threefold increase in download speeds during web surfing was recorded: 102 Mbps for the median category of users of 4G LTE networks versus 333 Mbps in 5G NR networks;
    • an approximately threefold decrease in response time was observed: the median delay in loading decreased from 48 to 14 ms;
    • about a fourfold increase in the speed of downloading files in conditions of a weak signal is visible: 131 Mbit / s for 90% of users in the 5G network versus 32 Mbit / s for users in the LTE network;
    • for users in the 10th percentile, the quality of streaming video has increased from 480p at 30 fps from 8-bit color rendering (LTE) to 8K at 120 fps from 10-bit color and above (5G).

    Figure 3: User experience on LTE Cat 9 and 5G NR devices in comparison

    The obtained results testify not only to an increase in data transfer speed in 5G networks, but also to stable communication quality even when working on the edge of a cell, which allows us to think about completely new usage scenarios such networks.

    The simulation also allowed for a general comparison of various categories of devices in specific conditions. In Figure 4, in particular, you can see that:

    • recorded a significant increase in performance when using 5G NR networks, for example, a speed increase to a gigabit level, reduced latency, stable communication quality and increased network capacity;
    • The importance of Gigabit LTE networks is to provide high-speed and stable communications for users who leave the 5G NR coverage area.

    Figure 4: Key indicators for modeling in Tokyo with irregular traffic - data taking into account the results obtained from the devices of the 90th percentile

    Uplink data modeling (uplink) on 5G NR networks up to 6 GHz in Tokyo

    Achievable data rates using 5G networks are often the subject of active discussion. And almost always we are talking about the speed in the descending channel from the network and what new opportunities this can give, but very little is said about the speed in the uplink channel (uplink). But the last parameter is no less important, because application developers need to understand what speed in the uplink should be expected from new generation networks before they start developing or updating their products.

    That is why we were the first in the industry to add the ability to announce detailed modeling of data upload speeds as part of our platform for testing the capabilities of 5G NR networks and user experience of interacting with them. This platform is designed so that it provides quantitative data on the expected real-world network performance in data upload and user experience when working with multi-mode 5G NR and Gigabit LTE TDD devices operating in 4G / 5G NR autonomous architecture networks.

    As can be seen in Figure 5, the tests showed an almost threefold increase in the speed of data unloading during the transition using a mixture of various devices from LTE networks to 5G NR networks.

    Figure 5: Results of simulating the capabilities of 5G NR networks of an autonomous architecture in the range below 6 GHz for the uplink data channel

    Figure 6 shows an example of a 5G NR device implementing a traffic model corresponding to loading a PowerPoint file into the cloud. The maximum upload speed in this usage scenario reached 78 Mbps and it took less than 30 seconds to transfer the file. The figure also shows key indicators, including signal quality, spectral efficiency, MIMO rank, and spectrum frequencies.

    Figure 6: File upload speed and key indicators when using 5G NR SA networks in the range below 6 GHz

    Broadcasting live video content is another important example of the use of modern devices. The quality of the broadcast here is directly dependent on the speed of uploading data to the network (in uplink). Considering that many social networks already offer the function of video broadcasts, the number of interested users is gradually increasing. Figure 7 shows a comparison between average speeds using LTE UL CAT 13 and 5G NR. The simulation showed that the user of 5G networks can broadcast live video in 4K without degrading the image quality due to packet loss, while the LTE CAT 13 user does not have enough network bandwidth to transmit data above 240p, and even In this case, part of the packets is lost and the picture periodically “freezes”.

    Figure 7: Comparison of live video transmission between SA 5G NR in the range up to 6 GHz and LTE UL CAT 13

    Making the dream of 5G a reality: from simulation to reality

    The modeling of the capabilities of 5G networks and user experience of interaction with them demonstrated the potential of 5G technologies, its performance and the operation of 5G and Gigabit LTE TDD networks in real conditions in real conditions. The results also confirmed a significant increase in the speed of loading and unloading data, which allows to achieve 5G NR, and the readiness of these networks to completely new use cases and the implementation of new services.

    In addition to this simulation (and other similar ones for other cities of the world), Qualcomm conducted large-scale field tests during the year to test the Qualcomm Snapdragon X50 5G modem. This was done in conjunction with major OEMs, infrastructure providers and mobile operators. And this is another step leading to the appearance on the market of the first wave of consumer devices with 5G support, which is expected in the first half of 2019.

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