Rakuten explains vendor roles in greenfield network

Despite COVID-19 and the upheaval it has wreaked across the globe, Rakuten Mobile is still planning to commercially launch its greenfield 4G network in Japan on April 8. Rakuten Mobile CTO Tareq Amin said that when the operator offered a March promotion for early subscribers, it was overwhelmed with the number of applications. It crashed Rakuten Mobile’s website, and the number of Twitter posts about the launch made the Guinness Book of World Records in Japan.*

Rakuten is offering an unlimited plan for data within its own network areas for about $28 per month. When subscribers ride on partner networks, data is capped at 2 GB per month. Its introductory price is cheaper than the incumbent mobile operators in Japan. However, its footprint is fairly limited to start, so subscribers may see expensive roaming fees if they’re not careful.

RELATED: Rakuten Mobile unveils low-cost unlimited plans in Japan, makes new U.S. hire

Ever since Rakuten started talking about its new network, it has named a lot of vendors that it’s working with. It initially named Cisco, Nokia, Altiostar, Intel, Red Hat (now part of IBM), OKI, Fujitsu, Ciena, NEC/Netcracker, Qualcomm, Mavenir, Quanta Cloud Technology, Sercomm, Tech Mahindra, Allot, Innoeye, and Viavi. Airspan has also been associated with the company in the past year.

It’s gotten kind of confusing to try to understand who’s doing what for Rakuten. Several of the vendors have claimed to be the primary software provider.

Amin set the record straight, saying Rakuten is overseeing all of the network software itself and acting as its own systems integrator. There is not a single vendor that is doing managed services for Rakuten. “We only do operation support contracts,” he said. “We are in control of our own destiny.”

In order to be in control, Amin said, “I was personally micromanaging to a level of detail because I knew if we didn’t act as the systems integrator we would never accomplish such a thing. We had to make sure all these vendors, who are competitors, we had to convince them to collaborate and work together, do the integration in our labs.”

Rakuten has been circulating the following slide, showing its simplified network architecture.

Rakuten slide

Its primary vendor for remote radio head hardware at its macro sites is Nokia. The Finnish vendor agreed to open up its CPRI interface in order to work with Rakuten. Amin said this was a big concession for Nokia, which he really appreciates, because in the past, vendors kept their CPRI interfaces proprietary so that operators would not have the choice of mixing and matching hardware and software.

For its data center architecture, Rakuten used Cisco’s hardware and software. “Cisco owns the IP layer,” said Amin. “We’re happy with the Cisco platform and did not have enough justification to disaggregate that layer.”

Rakuten also operates one horizontal cloud layer above its macro cell sites, edge data centers and central data centers. The cloud runs on Red Hat’s OpenStack platform with contributions from Cisco. “I really consider us to be a 100% open source platform because the entire virtualization layer is actually open source, Red Hat OpenStack,” Amin said. "This was the heart of running the entire system. Cisco helped harden the system.”

The main software contributions for Rakuten’s virtual radio access network (vRAN) came from U.S.-based Altiostar, a company Rakuten has invested in. “We wanted to protect the company from being acquired because we need a disrupter in this industry that could challenge incumbents,” Amin said.

RELATED: Airspan, Altiostar package lessons from Rakuten

On top of its cloud, Rakuten is working with a variety of vendors that provide virtual network functions (VNFs), which run on six hardware types that were designed by Rakuten. “All these vendors never came with a piece of hardware,” said Amin. “We dictated our entire infrastructure. My hardware is entirely commoditized.” He said Cisco provided the software for the evolved packet core (EPC); Nokia provided the IP multimedia subsystem (IMS) core; and Mavenir provided the instant message and rich communications service (RCS). All this software was provided as VNFs, running on Rakuten’s telco cloud.

Support Systems

Amin said it was the little things that caused some of his biggest headaches. For instance, the backend support systems for policy and charging were a challenge. Rakuten is actually planning to acquire a BSS/OSS company that it worked with on the project. Amin refused to name the company at this point because the deal is in final negotiation stages. But he said to look for an announcement in about three weeks. (Looking at the slide, we can deduce that this BSS/OSS company is either from India or the United States).

RELATED: Rakuten Mobile’s CTO says RAN wasn’t as troublesome as other things: Special Report on Automation

“I’ve never been a big fan of how the OSS layer has been orchestrated for the past 20 years,” he said. “If you are in any telco today, you will discover 100-plus boxes that do different things. The OSS/BSS platform we have built converges everything, converges these 100 separate boxes with artificial intelligence and machine learning.”

Amin said the company was able to pull all this together so quickly because he “micro-managed” a lot of things and had a lot of direct reports from 28 departments, who have a mix of mix of telco and non-telco expertise. His engineering staff totals about 350 people, whose average age is 31. “I really wanted to eliminate middle management,” he said. “We work in near real-time decision making.”

On to 5G

The telco ecosystem around the world has been watching Rakuten’s progress and will be curious to see how its network operates after commercial launch. Some have noted that Rakuten’s initial network is limited to just three major cities: Tokyo, Nagoya and Osaka. Outside of those areas, Rakuten relies on KDDI’s network. If subscribers must roam, they may be subject to significant roaming fees.

The company isn’t resting on its laurels, though. It’s continuing its network buildout with plans to nearly double the number of base stations by March 2021. And it plans to transition its network to 5G as soon as possible. It’s already working with Airspan to densify its network in mmWave spectrum. And it’s also working with the Japanese vendor NEC to develop a 3.7 GHz massive MIMO 5G antenna radio unit (RU), which will be manufactured by NEC at its facilities in Japan.

The company’s ultimate goal is to provide mobile coverage for 96% of the Japanese population with its own network.

*After publication of this article, Rakuten corrected its statement about the March promotion. Its March 3 event broke the Twitter record in Japan for the number of unique viewers of a livestream, with over 10 million page views.