At Qualcomm Technologies, we’ve been calling 2017 the year of Gigabit LTE. It has been an exciting 9 month non-stop marathon for us and Gigabit LTE momentum globally. It all commenced in January, at The Gigabit LTE Experience event in Sydney where, along with Telstra, Ericsson, and Netgear, we marked the arrival of the world’s first commercial Gigabit LTE mobile device and network.
Fast forward to present day and there are now 41 operators in 24 different countries deploying or trialing Gigabit LTE, including the four major U.S. operators. This is coupled with 16 capable Gigabit LTE devices with 10 Gigabit LTE premium smartphones available, powered by the Qualcomm Snapdragon 835 Mobile Platform featuring the Snapdragon X16 LTE modem, and only on Android.
The real-world benefits reported in this post make it clear why Gigabit LTE has seen such rapid wide-scale adoption. These benefits — significantly faster download speeds and dramatically better network and spectral efficiencies — are based on real-world user experience testing that Qualcomm Technologies commissioned with Signals Research Group (SRG), a well-known firm with deep expertise in wireless performance benchmarking, comparing a Gigabit LTE smartphone (Category 16) like the Samsung Galaxy S8 vs. a smartphone that only supports Category 12 LTE (up to 600 Mbps peak download speed). The latter represents the LTE capabilities of some recent non-Android flagship smartphones.
Here is a quick summary of the LTE capabilities of the two smartphones:
Benefits of Gigabit LTE devices with real-world applications
For the user experience testing, SRG performed a number of test scenarios that were largely consumer focused. This included:
- Google Play Store download (downloading a mobile game - ~350 MB)
- Google Drive download (downloading a ~2GB file, downloading 3 videos)
- YouTube streaming (4K 360° video)
- Video Streaming (15Mbps encoded video)
To quantify the performance SRG used user experience KPIs including video freezes as it relates to overall performance, and download times for the other Google Play Store and Google Drive scenarios. Other, more generic, metrics were also included, such as MIMO Rank (the number of maximum data streams a device can successfully receive and decode) and Network Resource Blocks (the small chunks of spectrum used by the network to send data to the device).
The below table summarizes the stellar performance and better user experience observed on the Gigabit LTE-capable Galaxy S8 compared to the Cat 12 smartphone, on a network that supports 4x4 MIMO on a single LTE carrier with 256-QAM, for peak download speeds of 400 Mbps. So while the network itself is not a Gigabit LTE network, the Gigabit LTE device is able to realize better performance than the Cat 12 smartphone:
In excellent signal conditions, the Samsung Galaxy S8, with support for 4x4 MIMO, added up an additional layer of data lanes on top of the existing ones to carry more data on the same amount of spectrum, compared to the Cat 12 smartphone. At the edge of the cell, the two extra antennas helped lock on to a stronger, cleaner signal from the tower — a technology called “4-way receive diversity” — allowing the Galaxy S8 to receive more streams of data and boosting download speeds. Figure 1 shows the mix of MIMO rank (Rank1 means 1 data stream, Rank2 means 2 data streams, and so on and so forth) for both smartphones.
To sum up:
- The Samsung Galaxy S8 users get better user experience measured by:
- Faster download times
- Better video quality
- Thanks to 4x4 MIMO, the Galaxy S8 uses fewer resources from the network, improving its capacity.
Benefits of Gigabit LTE with LAA devices with real-world applications
Gigabit LTE with LAA (License Assisted Access), an LTE Advanced Pro technology, combines unlicensed spectrum (5GHz) with licensed spectrum through carrier aggregation to increase network capacity. More and more networks are deploying LAA small cells, given its performance boost for smartphone users, and the capacity gains it provides optimizing network resources.
Google Play downloads were tested by comparing Galaxy S8 to the Cat 12 smartphones on LAA small cell that supports a single 20MHz Licensed cell along with three 20MHz unlicensed carriers – for a total of 80MHz spectrum.
Here is a summary of the results:
Although the median download speed with LAA for Galaxy S8 was a stellar 285 Mbps, the real benefit of LAA lies elsewhere. LAA distributes traffic between the licensed and unlicensed bands, freeing up capacity on the licensed spectrum connection, which can improve speeds for other users on those bands. A breakdown of bandwidth distributions is shown in Figure 2.
Impact of Gigabit LTE devices on overall spectral efficiency
SRG also analyzed spectral efficiency benefits to operators across a range of network conditions, from near cell — right next to the base station — to far cell, with more challenging conditions at the edge of cell. The study showed a significant gain (up to 50 percent) in spectral efficiency when using the Samsung Galaxy S8 with Gigabit LTE, providing a better experience not only to those who use Gigabit smartphones, but to all users on the network. Figure 3 shows the Physical Layer resource block (RB) normalized data rates at signal conditions. The RB normalized data rates are the implied data rates if the mobile devices had been assigned all available network resources (RBs) by the network:
There’s nothing better than real world results to prove the benefits of a Gigabit LTE technology. I will leave you with a few good nuggets to remember:
- Gigabit LTE smartphones provide better user experiences than Cat 12 smartphones:
- Faster download times
- Fewer network resources utilized
- Gigabit LTE smartphones mean virtually everyone in the network benefits
- Spectral efficiency increased by 30-40 percent
- Improved network capacity and ability to serve other users faster.
- Gigabit LTE with LAA technology provides better user experiences vs. devices that do not support LAA:
- 2x faster download speeds
- Offloads networks and increases capacity