On Rakuten Mobile technology and the future: Two years on from full commercial launch

Tareq Amin, Chief Executive Officer, Rakuten Mobile

As Rakuten Mobile celebrates two years since full scale commercial launch, I would like to look back over the incredible technical achievements of our team over the past two years and how we have laid the ground for our future direction.

“At Rakuten, 5G is not an afterthought but a part of the way we have designed our architecture from day zero.”

Tareq Amin, CEO, Rakuten Mobile & Rakuten Symphony

After Japan’s Ministry of Internal Affairs & Communications approved our 4G base station deployment plan and allocated spectrum in the 1.7GHz band to Rakuten Mobile in April 2018, we initially considered building our network with a traditional telecom vendor. But because of our culture of innovation powered by technology, we took a bold step toward a completely different approach. We decided to do something that had to date only been an idea on paper: to transform the way mobile networks are built and operated.

Virtualization technologies

We set out to build a virtualized, cloud-based mobile network. This would fully leverage the agility, speed and cost-efficiency of software-centric clouds commonly used in other industries around the globe today.

To achieve this, we introduced innovation in every aspect of the network, from the radio access network (RAN) to core to operations.

We started with the disaggregation of the hardware and software in the network. This meant we were able to realize a network design that draws on the expertise of multiple best-in-class partners, an approach that presented challenges in the traditional approach to building a mobile network. We removed all the proprietary hardware in the radio access network, including the base band unit, and instead designed the network based on software running on commercial off-the-shelf hardware.

Strategic and efficient base station deployment

In the base stations dotted around the country that are so crucial to effective network coverage, we deployed unique, customized RAN products. For 4G, we are using 160W high power radio heads with 4 transmit and 4 receive antennas (4Tx4R). By integrating the antenna and radio heads, we have been able to reduce cable losses, or the power lost over the length of a cable in the network, and achieve 30% more coverage per site in comparison to traditional deployments.

Carefully tailored to our allocated 4G spectrum, we have adopted a heterogenous deployment strategy to meet the capacity demand. Our RAN is made up of combination of macro, micro, indoor and femto cells. Through strategic deployment of these cells and a keen focus on densification, we are building both outdoor and indoor coverage, and we now have over 250,000 active radio units covering 4G and 5G.

Global recognition

Our network’s advantages are not hidden. Virtualizing the RAN enabled us to build base stations with minimal equipment at the site. This has made site acquisition easier and deployment faster. Our cells all run on the same software stack on standardized COTS hardware. Our total cost of ownership is 40% lower than that of traditional mobile networks. These advantages have enabled us to achieve 96% population coverage in Japan in February, about four years ahead of the targets set out in our original plan.

The high ranking of our network performance in third-party industry reports is a testimony to our unique achievements. In the most recent study from independent research company umlaut, our network in Tokyo scored 945 points out of 1,000. Compared to other operators, Rakuten Mobile’s network performance in Tokyo ranked highly, surpassing the top rating networks in eight global cities from Seattle to Rome, and coming in very close to the top-ranking networks of cities like New York, Sydney and Zurich.

Towards the 5G era

At Rakuten, 5G is not an afterthought but a part of the way we have designed our architecture from day zero. Our virtualized approach has enabled us to deploy 5G through a software upgrade. Our 5G RAN is completely containerized and designed based on microservices architecture. 5G technology will enable us to leverage high capacity 400 MHz in mmWave, and 100 MHz in sub-6 with low latency and high speed.

Our unique network product portfolio unleashes the real power of 5G. Our use of massive MIMO technology provides our customers with optimal coverage, capacity and 5G speed in the true sense envisioned at the outset of the 5G era. Every one of Rakuten Mobile’s 5G sites is massive MIMO capable today, ready to provide a 5G customer experience beyond parallel, at a fraction of the cost of a legacy network.

The base our technology has created for a unique and distinct network gives me the confidence in our ability to continue to provide our customers with the best possible experiences in 4G and 5G. It also gives me the confidence to say that we will continue to improve that experience, day-by-day, with every software upgrade and with the full dedication and commitment of the whole team at Rakuten Mobile.