NTT Docomo pitches itself as open RAN pre-integrator

Long before open RAN was an industry talking point, Japan's NTT Docomo was mixing cocktails of one vendor's radios and another's baseband boxes. Dating right back to the days of 4G, its skills as a mixologist arguably make it the most experienced systems integrator in the world in the open RAN area. The Japanese operator looks uniquely qualified to educate or advise the industry.

That is exactly what it now seeks to do, partly through a tie-up with UK-headquartered Vodafone announced at the FYUZ event in Madrid this week. It is not about altruism. Lining up a full menu of open RAN cocktails should ease consumption by telcos, generate economies of scale for those combinations and ultimately lower costs for everyone. The importance of that was underscored this week when Mavenir, a software developer and small maker of radios, grumbled that it pays much higher per-unit prices for components than big rivals buying larger quantities.

The initiative also reflects concern about "lock-in." That expression usually refers to a telco's dependency on a big kit vendor like Ericsson or Nokia. But there is anxiety about "creating a new kind of lock-in" with an external systems integrator such as India's Tech Mahindra, said Yago Tenorio, Vodafone's network architecture director. Telcos might be more willing to lean on the experiences of Docomo and Vodafone than hand control to someone integrating technologies from scratch.

Figure 1: Vodafone's Yago Tenorio worries about systems integrator lock-in with open RAN.
(Source: Iain Morris/Light Reading)

None of this is a guarantee of success. Sadayuki Abeta, Docomo's head of open RAN, likens the "pre-integration" his company does to the work that takes place at Ericsson or Nokia before their products see daylight. Like those companies, it promises support for telcos using these pre-integrated products – as a single throat to choke or head to bash. If it is the repository of all the knowhow, Docomo could start to look like another potential jailer.

Even Tenorio recognizes that possibility when discussing Rakuten, a high-profile rival of Docomo now doing systems integration work for other telcos. "In essence, the difference between Rakuten and Ericsson is none," he told Light Reading. "One claims it is open RAN and the other doesn't, but the fact is you are buying it from Rakuten and you are locked in and that is a risk."

Docomo's pitch also implies that systems integration has not grown easier with the availability of new interfaces devised by the O-RAN Alliance. But this does not invalidate the group's efforts, said Abeta. In the 4G days, it had to ask vendors to support a common interface before it could even think about stitching products together. If vendors stick to the O-RAN Alliance specifications, this can be taken for granted. Integrating technologies takes less time than it used to do, he said.

Previously, Docomo revealed it was using Fujitsu and NEC as suppliers of baseband products and radios in different parts of the country, along with Samsung and some "smaller Japanese vendors" on the radio side. It is also known to have used Nokia as a baseband provider. Yet Abeta doubts the market will be able to support numerous smaller players and thinks merger activity is likely. "I don't think in future we will have so many vendors," he said. "Still, with open interfaces and architecture, an operator can choose or replace if necessary."

Inline over Intel

The next stage for Docomo is adding virtualized products to its open RAN ecosystem (OREC, as Docomo calls it). Aiming to virtualize part of its RAN next year, it is currently investigating different options for hardware acceleration, a technique designed to overcome the performance limitations of using general-purpose processors in the RAN.

Intel has backed an option called "lookaside" and, more recently, something it is promoting as "integrated" acceleration, both of which, unsurprisingly, continue to rely heavily on the x86 processors that Intel provides. Rivals including Marvell and Qualcomm prefer a technique known as "inline," which offloads various baseband functions onto more dedicated silicon. Docomo is conducting trials with chip developers such as Intel, Nvidia, Qualcomm and Xilinx, but Abeta seems drawn to inline for the performance benefits it promises.

He is confident virtualization can drive down costs for NTT Docomo. Partly, that is because it can use the same common, off-the-shelf (COTS) servers for a range of functions, including the core network, data center and RAN. Instead of buying dedicated RAN hardware, it could purchase COTS servers in bigger quantities and negotiate more favorable deals.

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Competition for Intel could also lower prices, according to Abeta. "AMD and Arm are coming into this market and that adds competition," he said. Former research carried out by Omdia, a sister company to Light Reading, showed Intel's share of silicon used in data center servers had tumbled from 98% in 2017 to 77% last year as AMD and Arm-based alternatives made headway.

"The whole RAN market is relatively small when compared with data centers and over there Intel has a problem because Arm is being adopted more and more," said Joel Brand, the senior director of product marketing for Marvell. Due to report its latest financial results this week, Intel noted a 16% year-on-year drop in revenues at its data center unit for the second quarter, to about $4.6 billion, alluding in its earnings report to the "competitive environment."

A rapid virtualization of Docomo's 5G network is unlikely, though. As Abeta points out, the operator's 5G network has already been extensively deployed across Japan, today comprising more than 20,000 basestations. Rolling out virtualized products would mean having to rip out the technologies it has recently installed. Open interfaces or not, Docomo would need to have a very good reason to write off all that expense.

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— Iain Morris, International Editor, Light Reading