MWC19: Rakuten provides a template for how the future 5G network could look

Japan’s ecommerce company, turned MNO, Rakuten, was certainly the belle of the ball at MWC this year, and not just because they are the lead sponsor for the beloved local soccer team, FC Barcelona. The company acquired spectrum last year and is building a greenfield 4G network to convert its existing MVNO business into a full mobile platform, chiefly to drive usage of its digital services, such as shopping and banking, and to enable new applications.

There wasn’t too much hype at MWC this year, certainly not on the network side, but there was a loud buzz around this entirely unproven MNO, which is deploying 4G not 5G, in one of the world’s most saturated markets. But the excitement was there because Rakuten was showing a glimpse of what could be done with the modern mobile network, promising to support a number of concepts which are often discussed but, for most MNOs, are still far from at-scale reality. These include virtualized RAN, edge computing, network slicing, end-to-end automation supported by AI, an IPv6-based transport network, a unified OSS layer, and a cloud-native packet core with full control/user plane separation.

The company’s mobile ambitions may collapse, or it may remain a unique example of a cloud-centric MNO, in a unique market, with little impact on the international mobile industry. But it is proving what sometimes looks like being an impossible – or at least, just too difficult – dream to achieve, a cloud-native end-to-end network driven entirely by digital services, not bits and bytes.

It was also interesting that Rakuten allowed its suppliers to make themselves public, which highlighted another aspect of its deployment that others, encumbered by legacy processes and networks, may covet – a fully multivendor roll-out integrating traditional and disruptive suppliers, held together by open interfaces (and a hefty outlay on turnkey services from Nokia and a lab collaboration with Tech Mahindra).

Other suppliers include Altiostar, Cisco, Intel, Red Hat, OKI, Fujitsu, Ciena, Netcracker, Qualcomm, Mavenir, Quanta, Sercomm, Allot, Innoeye and Viavi.

Not everything in Rakuten’s network is radical. Most of the suppliers are familiar names, and Nokia is doing the integration and deployment of the network. Many of the individual elements have been adopted by more conventional MNOs too, just not altogether in a holistic deployment. Compared to the blueprint established by Vodafone and Orange in their RFPs based on Telecom Infra Project (TIP) specs, the supplier list is conservative (the successful companies which complied with those RFP requirements included a long list of small or start-up  providers of small cells and virtualized RAN or core).

But the TIP exercise did not promise large-scale commercial deployment, while Rakuten is already in the process of rolling out its new-look network, at least in certain cities of Japan (it will rely, for some years, on a roaming deal with KDDI to achieve coverage).

As befits a cloud provider, everything is deployed natively on cloud infrastructure. Rakuten is working with Red Hat to build its NFV cloud, implementing three of the companies’ offerings – the Red Hat Enterprise Linux operating system; OpenStack Platform for Infrastructure-as-a-Service (IaaS); and Ceph Storage for massive software-defined storage functionality.

“The next generation of mobile networks isn’t defined by inflexible, proprietary solutions; it’s frequently founded in cloud-native technologies driven by open source. From 5G to augmented reality, many advancements in mobile services are being powered by open software on open standards-based hardware,” said Chris Wright, Red Hat’s CTO.

At the RAN level, the vRAN comes from Altiostar, in which Rakuten has taken an investment. The supplier’s baseband is fully virtualized on COTS hardware, in this case from Quanta Computing Technology (QCT) of Taiwan, though other vendors’ boxes could be introduced too. The servers will run on Intel processor/FPGA combinations.

The Quanta boxes are deployed in aggregation centers, which in future might also house edge nodes, and these centers serve clusters of radio cells. Rakuten will build 4,000 virtual distributed units and two central data centers to support the vRAN. This infrastructure will handle baseband processing and connect to the remote radio heads that Rakuten is sourcing (Nokia AirScale).

Altiostar makes a high layer functional split between virtualized baseband functions and those at the cell site, supporting 3GPP’s Option 2. This means most functions are centralized, while another group pushing more open networks, the ORAN Alliance, is focused on the lower layer Option 7. Most importantly, though, this RAN points to the long-held MNO dream of a network in which basebands and radio heads come from different suppliers.

Altiostar’s head of strategy, Thierry Maupile, told TMN: “This is the first time this has been done and at this pace – the first time for a fully virtualized Layers 1-3 vRAN. We are taking advantage of the excellent fiber estate in Japan, putting all the base stations on an edge cloud.”

There will also be large numbers of small cells – what Rakuten calls ‘lean’ outdoor radio/antenna units with efficient siting requirements – from an unnamed vendor but running on Qualcomm chips. Qualcomm has also provided test devices.

As well as Rakuten itself, Tech Mahindra is an investor in Altiostar, and has a role in the Japanese deployment, as its 5G Lab collaborator, working on testing and future use cases. It may also do some of the systems integration, though Nokia is the primary contractor for the whole network.

The cloud-native core is also a multivendor affair. The main core is coming from Cisco, but Nokia is also providing elements from its AirGile family, and is working with Rakuten on several future core functions designed to harness AI-assisted automation to reduce opex. Another important aspect of opex reduction will be that Rakuten has fewer than 10 SKUs (stock keeping units) to maintain, because it has opted for standard, uniform infrastructure – this compares to hundreds for most operators.

There will be a common orchestration and OSS layer on the telco cloud, managing all the virtual functions in the RAN, core and transport. The cloud will include distributed or edge nodes which, combined with control/user plane separation (CUPS) in the packet core, will enable mobile edge applications.

The mobile backhaul network is being built from launch to be ready for 5G capacity and density, said Rakuten’s CTO Tareq Amin (formerly CTO of equally disruptive and modern Reliance Jio in India).  The network core will have multiple terabits of capacity and multiples of 100G of bandwidth will be made available to the cell site pre-aggregation network. This network will be based on IPv6, to support very high numbers of devices and IoT end points.

Finally, Rakuten will use Netcracker’s end-to-end digital BSS (business support system).

All this architectural innovation will be pointless unless it enables Rakuten to enhance its existing digital services, and launch new ones, in a fully agile way which leverages its new control over mobile network quality and user experience. Of course, Rakuten already has a digital services platform, but one of its objectives in building its own mobile network is to shift its revenue balance more towards the enterprise, and particularly the Internet of Things (IoT). Here, it is also working with Nokia, choosing the Finnish firm’s Impact service, which promises to simplify the process of deploying large numbers of IoT applications, and scaling them up or down, from a single platform.

Rakuten has carried out lab testing, working with Viavi, as well as tests in a real world environment near its headquarters in suburban Tokyo. It will now expand those trials across western Japan, to involve about 10,000 users, with a view to service launch in October. The aim is to start introducing 5G in 2020, subject to government licensing approval.

The new network has come about because the operator secured 2×20 MHz of spectrum in the 1.7 GHz band in three of Japan’s eight telecoms operating regions and is in the process of acquiring airwaves in more regions, plus unpaired frequencies in 3.4 GHz. The Japanese regulator awarded the new licences to stimulate competition and break what a government representative called the “cooperative oligopoly” of the incumbent trio. Rakuten is targeting 96% population coverage within six years, and 10m subscribers by 2028.

It believes it can leverage its cloud-native approach to deploy its networks at low cost – a targeted ¥526bn ($4.7bn) over five years, which contrasts with NTT Docomo’s projection of spending ¥200 ($1.8bn) a year for the next five years on 5G alone. The cost-efficiency will also be helped by deals with several utilities to use their infrastructure to support the mobile roll-out. Rakuten may then go on to buy 5G spectrum.

For now, gaps in its spectrum, or its build-out, will be filled by its MVNO agreement with KDDI. Japan’s second MNO is in the strange position of enabling the newcomer and having to respond to the new competitive threat from a far more agile, cloud-oriented provider. The two companies’ deal goes well beyond a traditional MVNO contract. KDDI will “provide roaming services to Rakuten for its 4G mobile network”until March 2026, the companies said, enabling the latter  “to offer a nationwide LTE service from launch”. Meanwhile KDDI will use Rakuten’s payment platform and network of around 1.2m affiliated stores in Japan to launch its own barcode and QR payment service, called au PAY, in April 2019.