vRAN a Hot Topic at MWC18

Virtualized radio access network (vRAN) technology was a hot topic at the 2018 Mobile World Congress (MWC). Seemingly every equipment vendor, mobile network operator (MNO), and chip supplier had something to say about virtualization and vRAN. There are even competing or overlapping initiatives from industry associations, as many attempt to reap the benefits of vRAN.

vRAN promises an MNO reductions in CAPEX and OPEX, along with scalability in the RAN, allowing the MNO to scale network resources up or down according to traffic demand. Having a vRAN means that an MNO no longer has to over-provision the RAN by designing for peak demand. The RAN is run in software by using network functions virtualization (NFV) to replicate the baseband functionality of the basestation in a telco data center running commercial off-the-shelf (COTS) server hardware.

The announcements that caught ABI Research’s attention are listed here by company. This may not be a comprehensive list, as we may have missed some press releases. What was truly a head-spinning torrent of press releases during the event has been compiled in an “at a glance” illustration below, with more in-depth detail below.

MNOs announcing vRAN initiatives were: AT&T, China Mobile, Deutsche Telekom, NTT DOCOMO, and Orange jointly creating the Open RAN (ORAN) Alliance from the combination of the xRAN Forum and the C-RAN Alliance. Verizonalso plans to virtualize the RAN, announcing that it has partnered with Intel and Nokia to develop a vRAN architecture, and partnering with Samsungon its 4G LTE Open RAN initiative. Sprint and Caviumannounced a collaboration on virtualization for both the network core and the RAN. Facebook’s Telecom Infra Project (TIP), which explores vRAN among other topics, also announced that China Unicom, Sprint, and Telenor are its newest members. T-Mobileannounced that it would start building its 5G network in 30 cities this year with both Nokiaand Ericsson, and leveraging the virtualization features of Nokia’s AirScale Radio platform and the Ericsson Radio System (ERS). In Europe, TIM and Ericssonannounced the start of their vRAN efforts in preparation for 5G. BT, Mavenir, and ADVA announced a collaboration on vRAN as part of Facebook’s TIP project. BT, Cavium, and Nokia also announced plans to trial TIP’s OpenCellular LTE (OC-LTE).

Small cell vendor announcements about vRAN efforts include those from Accelleranand Eurona Telecom and Netsia; Altiostarand Sercomm’s complete end-to-end CBRS solution for fixed wireless; and Parallel Wirelessand Telefónica’s successful technology pilot based on Parallel Wireless’ Open RAN in remote Latin American communities.

Following the same trends as those in outdoor market and not to be outdone, the distributed antenna system (DAS) vendors had a great deal to say about vRAN. ASOCSdemonstrated a fully-virtualized RAN; Cobhamenhanced its idDAS with vRAN capabilities; CommScopeannounced its latest Era DAS; Dali Wirelessannounced its latest Virtual Fronthaul Interface (vFI); and JMA Wirelesslaunched its new XRAN (not to be confused with the xRAN Forum) DAS and said that it is working with TIMon RAN virtualization. SOLiDannounced its GENESIS DAS as an evolution of its existing vRAN-based GENESIS RAX solution.

In addition to Facebook’s TIP and the newly created ORAN Alliance, Ciscoannounced its open vRAN ecosystem and reported that Altiostar, Aricent, Intel, Mavenir, Phazr, Red Hat, and Tech Mahindra have confirmed plans to join.

The proliferation of the many types of vRAN surely comes from the fact that there are many ways of decomposing, partitioning, or splitting the baseband function for virtualization, and without standardization, many approaches are vying to become the de facto standard. The ABI Insight “Virtual RAN Gets Real,” which was published last year, outlines the multiple baseband partitioning choices and the performance trade-offs associated with each choice, as well as the limitations imposed by the fronthaul and the fronthaul protocol used. This explains the number of attempts at vRAN.

The number of players and the momentum from many major MNOs is a sign that the pending 5G rollout will be uneconomical if costs are not slashed from the RAN. For a 5G RAN in the low bands (sub-1 GHz) its build costs will be broadly similar to current LTE networks for comparable cell site density. On the other hand, delivering on the promises of 5G in the mid bands (1 GHz to 6 GHz) and high bands (millimeter wave) will dictate a much higher cell site density, which risks “breaking” the economics without a dramatic reduction in RAN costs. This reduction promises to come from virtualization and will involve re-architecting the RAN to become vRAN. MNOs must urgently adopt vRAN for 5G mid and high bands, given that the traditional model for macrocell deployment becomes unaffordable at these frequencies.

However, there seems to be as many approaches to vRAN as there are types and quality of fronthaul, with each approach making a slightly different decision about baseband decomposition, with differing trade-offs for each approach. Without the economies of scale that come from standardization, implementing vRAN will continue to be expensive.

While the business case remains to be completely proven, some MNOs urge caution. Disaggregating the baseband from the radio and connecting them with fiber fronthaul may entail new upfront costs, such as laying down new fiber and constructing new telco data center facilities. This would be an expensive consideration for MNOs without access to sufficient fiber.

The newly created ORAN Alliance, with backing from some of the largest MNOs in the world, illustrates an attempt to regain control of network architectures from established vendors, such as Nokia, Ericsson, and Huawei, among others, raising the prospect of these vendors competing with smaller software-based startups, as MNOs look to mix and match select components from different vendors in their RANs to achieve the best performance. However, this vision of a truly open vendor-agnostic RAN is an ideal world aspiration. In the real world, the hyper-competitive equipment vendors will likely strive to retain some form of vendor-specific hardware in the RAN to maintain their competitive differentiation.