Docomo open RAN head reveals challenges, progress

NTT Docomo divulged the key challenges operators face when contemplating a shift to open RAN systems, as it expanded the portfolio of an initiative to support others’ moves to adopt the approach and virtualised networks.

“We are not only working on developing the equipment, but discussing with partners how we can simplify lifecycle management, so it seems like a setup is from a single vendor.”

Docomo is pushing for a more unified lifecycle to address integration complexities caused by differences in the upgrade cycles between hardware and software, and chip vendors.

With Covid-19 (coronavirus) restrictions in Japan recently lifted, Docomo just started face-to-face meetings with potential clients, making some progress in lining up new business and receiving some frank feedback.

In terms of costs, Abeta admitted “it’s not so clear how much additional reduction operators can achieve when they introduce open RAN,” as system integration costs can vary greatly and each deployment is generally different.

He said Docomo is seeing keen interest from operators in its open lab, noting their biggest challenge in open RAN is system integration. “They don’t have the experience or capabilities in this area. With a minimum cost, they see they can have access to our lab,” which provides a pre-integration service covering end-to-end testing, including chipsets.

In addition to the investment costs, Abeta noted setting up in-house facilities can take up to a year, which isn’t feasible for most smaller players.

Another major obstacle is co-existence with legacy networks. “We ask vendors to use O-RAN Alliance profiles,” but some do not provide compatible interfaces, making it difficult to introduce an open network on 4G infrastructure.

Nearing deals
Docomo demonstrated its lab is able to control devices remotely to set up configurations for operators. It provided different test cases in an initial phase and is now planning mobility and load tests, along with tackling interoperability between different vendors.

Abeta stated Docomo is nearing agreements with two operators and is in advanced talks with a few others, noting it will likely conclude contracts in a couple of months and make announcements by the end of the year.

Docomo’s search for clients is global, with the open RAN head citing talks with operators across Europe, North America and Asia.

Compared with a few years ago, operators have a much wider choice of vendors of compliant equipment, with more frequency bands covered, which Abeta said is driving overall demand for open RAN.

However, working out deals takes time on the technical side along with the legal side. The process starts by determining the scope of the testing, with some operators having started limited trials on their own.

Projects tend to move slowly once underway, beginning with small trials then moving to larger deployments over up to two years.

Early start
Abeta highlighted Docomo developed capabilities during the 4G era, giving it experience in interoperability testing and product integration.

Having internal experts in its R&D team means it only had to gradually add staff to develop and deliver 5G services for customers.

Because Docomo used different vendors for different parts of the RAN in LTE, it defined interoperability itself and used an in-house interface, but with 5G it is using 3GPP-defined interfaces.

The strength of the team is boosted by working jointly with partners in the lab and also subsidiaries including NTT Data and NTT.

Abeta noted after adding a three vendor partners in 2021 taking its total to 13, Docomo has no plans to add more. “We first have to show improvements, such as optimising performance and lowing power consumption.”