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How Rakuten’s mobile network experience is evolving

In our latest analysis of the mobile experience of Rakuten users, we see big increases in the reach of Rakuten’s network as it expands across Japan and a resulting impact on users’ mobile experience. Rakuten stated in its November 2020 earnings report that it aims to cover 96% of Japan’s population with its cell sites and 4G radio network by the summer of 2021.

Now, in Opensignal’s analytics, we see that the share of users’ measurements connecting to Rakuten’s own radio network is now almost half — 48.3% in December — up from 39.2% in September. Plus, we continue to see users enjoying faster speeds when connected to the new Rakuten network, especially for upload speeds that are useful for sharing photos, videos and other large files.

Rakuten is a new mobile network operator in Japan that initially launched in April 2020. Since then, Rakuten has been expanding the reach of its new mobile network. In areas where the Rakuten network has not yet been built, Rakuten smartphone users roam onto a partner network, KDDI. In our previous analysis, we saw that the experience of our Rakuten users was considerably better “on-net” than when they are roaming. Now, we see that pattern in more cities.

We analyzed 15 cities across Japan, and compared the results in December with three months earlier in September to understand how quickly Rakuten is expanding the reach of its network. This is important because our users see much faster speeds as Rakuten’s reach improves.

Our Rakuten users saw large increases in the share of network measurements going to Rakuten’s new mobile network — connecting to the Rakuten radio access network (RAN) — in December in 10 of the cities, and smaller increases in several more. In just two, Kawaguchi and Fukuoka, we saw approximately the same share but this likely just reflects a temporary pause while Rakuten focuses its network investments elsewhere.

Rakuten has probably focused its radio network deployments especially on locations where it is able to deploy the full 20 MHz of 4G/LTE spectrum but in many locations Rakuten is currently limited to just 5Mhz of 4G/LTE spectrum. With 20 MHz of spectrum deployed, Rakuten is able to support a much faster experience than where it deploys 5 MHz.

As in our previous analysis, we see much faster download and especially upload speeds when our Rakuten users are connected to Rakuten’s own radio network. However, we see much greater consistency of “on-net” download speeds across the 15 cities in December compared with three months earlier. 

When we examine the same set of 15 cities and compare our Rakuten users’ download speeds between September and December, we see speeds are consistent and approximately stable in many including Osaka, Nagoya, Tokyo, Chiba and Kawasaki. In three — Fukuoka, Sapporo and Kobe — we see much faster download speeds in December perhaps reflecting network enhancements.

As Rakuten adds mobile customers onto its network, observers are correctly interested to see if increased usage affects mobile speeds. But it’s important to note that a national average may not show the real picture because so many factors are changing at the same time.

For example, Rakuten is expanding the reach of its network to many new locations. Some of these cities will be limited to 5 MHz of 4G/LTE spectrum and where possible Rakuten is upgrading locations to use 20 MHz. At the same time, Rakuten is also acquiring customers and managing the impact of the unique challenges of changed mobile behavior that every operator and every person faces in 2020 and 2021 due to the global crisis. The combination of these factors mean it’s important to look at city or regional results to understand how Rakuten users’ mobile experience is changing,

When we look at upload speed trends we see a similar picture. In most cities speeds were stable between December and September. But in a few — Fukuoka, Sapporo, and Kobe — our Rakuten users observed higher speeds in December than September. However, a national average may hide these trends because of the vast number of users in larger cities like Osaka, Nagoya and Tokyo.

Nationally, we continue to see the advantage that our Rakuten users have in upload speeds compared with the experience of our users on other Japanese operators. And, we see much faster download and upload speeds connected to Rakuten’s radio network than when our Rakuten users are roaming onto KDDI.

Opensignal will continue to analyze the evolution of the real-world mobile experience across all of Japan’s operators.