Rakuten Mobile unwrapped its 5G network today, six months after activating its virtualized, cloud-native open radio access network (RAN) riding on 4G LTE.

The greenfield Japanese network operator walked through a series of activities and business strategies that led to its 5G achievement during a press conference just prior to making the new service commercially available. 

Rakuten’s 5G network currently covers six prefectures in Japan, including parts of Tokyo, Kanagawa, Saitama, Hokkaido, Osaka, and Hyogo. It plans to reach all prefectures in Japan by March 2021 and is preparing to deploy a 5G standalone network core in the second quarter of 2021.

The ecommerce giant’s mobile aspirations were delayed about six months behind schedule on 4G LTE and another three months on 5G, but it’s holding firm to commitments going forward. 

Rakuten Mobile EVP and CTO Tareq Amin detailed what he described as a “unique approach to engineering, architecting, and building a next-generation 5G network,” focusing on the network’s virtualized and cloud-native architecture, and its determination to deliver on the vision of open RAN running on commoditized equipment. 

“Our journey starts from understanding the cloud architecture, the principles of how to build a proper cloud platform for communication, the standardization that we have applied on hardware, the removal of proprietary architecture into a completely commoditized architecture, and most importantly, adopting a cloud-native architecture, microservices, containerized platform around 5G. That is what makes launching 5G in Rakuten uniquely different,” he said at the press conference.

Radios, in particular, have become the hottest and most debated topic in the industry, Amin said, taking credit for some of the changes hitting the telecommunications market at large. “We have innovated an architecture that was proprietary, that was closed, that was absolutely unwilling to evolve into an open RAN platform. We think this is the most crucial component for industry disruption and we wholeheartedly believe that this is just the beginning of what you’re going to see.” 

Rakuten’s entire mobile network runs on two versions of open RAN radios powered by Intel Xeon Scalable processors. Sub-6 GHz radios are built in partnership with NEC and Intel, and millimeter-wave (mmWave) radios are built in partnership with Qualcomm, Amin said. The operator is also relying on NEC for its standalone 5G core. 

“We have unlocked the mystery around radio. We have driven a discussion in the world about the necessity of open RAN architecture because that is where we realize the most amount of benefit from reducing cost in infrastructure,” he said. “This is a platform that is 50% less cost than a traditional architecture.”

Those proclaimed cost savings have been a moving target for Amin. When Rakuten Mobile deployed a 4G LTE network, he claimed the network architecture costs 40% less than traditional, proprietary infrastructure, adding that the savings on opex are even greater.

“With software, we are in a massive, opportunistic environment that allows us to drive better efficiency in software and platforms,” he said. 

Rakuten Mobile is, at launch, promoting speeds of 110 Mb/s on the uplink and 870 Mb/s on the downlink. A software upgrade planned for November will boost those speeds to 275 Mb/s on the uplink and 2.8 Gb/s on the downlink, according to the operator.

The operator is hitting its stride on 5G network deployments amid some shifts in the Japanese telecommunications market, perhaps a sign of more reactions to come from Japan’s incumbent mobile network operators. 

NTT this week inked a $40 billion deal to reclaim complete control of NTT DoCoMo. Following that news, it announced an achievement with Fujitsu and NEC, claiming the “world’s first carrier aggregation using 5G frequency bands in a multi-vendor RAN.” By adhering to open RAN standards, NTT DoCoMo said it used 3.7 GHz and 4.5 GHz spectrum bands to produce downlink speeds of 4.2 Gb/s.

Japan’s largest mobile operator signaled a strengthened resolve to embrace and deploy open RAN equipment, thereby limiting at least some of the more unique aspects of Rakuten Mobile’s framework.