Completing the connectivity puzzle

This article is part of a series highlighting the collaboration between Rakuten Mobile and its partners to build the world’s first end-to-end fully virtualized cloud-native mobile network. In this edition, we speak to James Wang, CEO of Sercomm Corporation.

One of the challenges of building a mobile network is managing performance in the hotspots. How do you provide a high quality signal inside a railway station, a shopping mall, a covered market or a densely-populated urban street?

This is where “small cells” come in. Designed to add extra capacity and coverage to hotspots, small cells employ compact and discreet antenna, rather than the radio towers that are a hallmark of a conventional base station. “With a service launch, you typically build the macro-cells first and then push on with the hotspots, which are basically indoors, cover all the service stores, the public areas and the residential users,” explains James Wang, CEO of Sercomm, which is supplying 4G/LTE/Wi-Fi small cells for the new Rakuten Mobile network in Japan. “We are producing thousands of units daily and we will be supplying large scale numbers of units in a very short time frame,” he adds.

Based in Taipei, Sercomm has been developing small cell technology since the mid-2000s. Working together with Rakuten Mobile, it has developed a small cell that can take full advantage of the flexibility of the operator’s groundbreaking network architecture in which the hardware is decoupled from the software.

Whereas traditional radio networks are characterized by complicated and opaque hardware and software, Rakuten Mobile has moved a lot of that complexity to the cloud, meaning Sercomm’s small cell equipment can be much simpler. As a result, “you have much quicker time to market and a much better structure, so you can save a ton of CAPEX (capital expenditure),” notes Wang. “It is much more affordable.” The new virtualized design splits the distributed unit from the control unit, making the small cells easy to install and highly reliable.

A seamless transition to 5G

To harness high capacity spectrum in the millimeter wavelengths, 5G networks will use specialized antennas and radios. The 4G small cells Sercomm is supplying to Rakuten Mobile can be upgraded to support 5G by swapping out the distributed units. The upgrade will involve “a simple hardware replace, everything behind that doesn’t need to be replaced, so we have better upgradeability,” Wang notes. “As we will have installed a large scale number of devices already, we will have done the most difficult part, which is how do you acquire the site, get the landlord approval, install backhaul and a power supply. Every single device we do for 4G, we prepare for 5G. We will simply swap them out — plug and play.”

Although Sercomm was able to leverage a lot of its existing expertise for the 4G/LTE/Wi-Fi Rakuten Mobile radio design, it has had to work hard to adapt that technology for Rakuten’s virtualized radio access network (RAN) architecture, which is managed by software developer, Altiostar. “We have collaborated with Altiostar on a lot of the software,” explains Wang. “It was about 18 months of engineering effort and we have had 50 to 60 engineers supporting the project, as well as 100 staff working in manufacturing for this ramp-up.”

Having been at the cutting edge of the cellular industry for more than a decade, Tareq Amin, CTO of Rakuten Mobile, has known Sercomm for a long time. “Sercomm has really stepped up to meet the challenge we set for them,” he says. “As the technology leader in small cell products, the team has been able to build and manufacture a solution that dovetails well into our cloud-native RAN and ensures that our customers can count on reliable, cost-effective and convenient connectivity, both outdoors and in.”

The patience of a pioneer

When Sercomm first started developing small cells in 2006 and 2007, it was a pioneer. But it took some time for demand to crystallize. “We were one of the first companies to jump in there,” recalls Wang. “It was a very lonely journey. With 3G and 4G, the whole network is architected end-to-end, fully integrated into one big piece. For a small cell player, it is really difficult to come into an ecosystem dominated by the big telecom OEMs (original equipment manufacturers).”

But the telecom equipment industry is now opening up, prompted in part by Rakuten Mobile’s decision to employ an end-to-end virtualized architecture using open technologies that can be supplied by multiple different equipment vendors. “A paradigm shift is going to happen with 5G: it is going to happen because of the economies of scale you get on operations, and the fact that maintenance is much easier with the new architecture,” explains Wang. “You need several pioneers to prove the suitability of the new technology. Mickey [Mikitani, Chairman and CEO of Rakuten] is a leader who has made a huge bet on this new tech and Tareq Amin has been able to educate the industry.”

As other operators increasingly look to move to virtualized architectures, the Rakuten Mobile partnership is strategically very important for Sercomm. “I need to be on the daily call with Rakuten Mobile,” Wang says. “We have to really change our pace to work around the clock, as the organization is very flat. Rakuten has become the systems integrator itself. The mindset is very, very different from that of a traditional telco mindset. Rakuten is really going to reshape the global mobile industry.”