A highlight of TIP’s annual summit is usually an upbeat commitment from Vodafone (and others) to open RAN architectures. Two years ago, Vodafone and Telefónica named the vendors with the best compliance with their first RFI (request for information), based on TIP principles for open RAN. Last year, Vodafone added the results of a 5G RFI, and pledged that it would open up all its RAN sites, over time, for open platforms, under tender.
This year, it was focusing on RFIs for specific elements of the RAN, namely the radio unit hardware. This is an important evolution of Vodafone’s TIP-based open RAN process – which will be influential on others too. It shows the operator delving into the details of the network architecture, rather than just xhaul interfaces. Those are relatively easy to implement, if only vendors agree to support them in a truly uniform and interoperable way (unlike CPRI).
Far bigger challenges in the virtualized, open RAN lie in the hardware to support the distributed units and radio units. The latter cannot, of course, run on cloud infrastructure, but needs to stay open and software-defined; the former should, in time, run on common edge cloud hardware, but its demanding near-real time functions will make this impractical, at least in macro networks, for some time, without significant performance trade-offs. These are issues that operators need to address with confidence before deploying at scale, as they face the rising traffic loads and QoS assumptions of 5G.
Vodafone announced the companies whose radio unit hardware best met the RFI requirements, and which would have commercial products by mid-2021 or before.
According to Vodafone’s head of network strategy, Yago Tenorio, he is shooting for a unit price of $1,000 or less, and said the most important categories in the RFI results were “multiband radios for Massive MIMO or single-band radios. From our perspective, and according to the requirements we use, these are the companies that you may want to pay attention to”.
That is a major marketing and credibility boost for the companies which performed well in this category. Vodafone is certainly not focusing only on western pioneers, as some operators are in the wake of the Huawei crisis. Among its chosen vendors in this key category are the USA’s RAN software supplier Mavenir, but also Hong Kong-based Comba Telecom and China’s NTS. And unlike its 5G open RAN RFI – which highlighted a tier 1 vendor (Samsung), and raised question marks over the readiness of smaller challengers – this one is all about alternative vendors.
An RU developed by Vodafone itself, based on TIP’s own 40W RU reference design, Evenstar, for the 1.8 GHz band, performed well too, and highlighted the potential for operators to use blueprints and reference designs from bodies like TIP to create their own systems – an approach Reliance Jio may adopt, although so far its inhouse efforts have involved close cooperation with vendors such as Airspan and Samsung. Evenstar hit the sub-$1,000 mark, unlike its rivals, and came third overall in the rankings, putting pressure on the others to reduce their prices.
“We may extend designs to other bands,” said Tenorio. “We might to reach multiband and maybe in the future do a Massive MIMO product.”
“We may also be designing our own baseband into Evenstar,” he added. “Why stop at the radio? Maybe you can have a whole base station that is white-boxed, and you can buy for a very low cost. We will be doing that too.” Vodafone is already working on a project with Dish Network, to design a white box for the open RAN CU and DU.
None of the major radio vendors featured in the list, despite the prominent work that Nokia, in particular, has done recently on open radios.
According to sources of The Mobile Network (TMN), Samsung – which won last year’s 5G open RAN RFI – did enter the RU contest, but was not selected because it did not tick enough boxes.
Tenorio said Vodafone would soon issue an RFI for the DU and CU in an open RAN.