5G Virtualized RAN CU-DU split

Virtualization for communications service providers started with the core network and subsequently cloud modern technologies have been evolving at a fast rate. In the RAN domain name, vendor agnostic commercial off-the-shelf (COTS) equipment has the prospective to enable innovation throughout a series of software ecosystems

A splitting up of the uppser and lower parts of the RAN was standardized in 3GPP R15, where a higher-layer split was defined with a distinct interface (F1) between 2 logical units: the CU called also Centralized Device and also DU called the Distributed System . The CU– with much less strict requirements– has been even more open to virtualization than the DU for which functions are much closer to the radio.

Why the Split?

‘Why we need to think of this sort of split?’.  The basic response would certainly be ‘it is due to the fact that this split aids to virtualize the network capabilities’. Virtualization typically imply flexibility as well as cost reduction. With this sort of split, we can think about a RAN implementation as shown  below. Up to know, it would be very challenging to virtualize the lower layer of gnodeb( PHY/MAC/RLC), however virtualization of upper layer (PDCP and over) is possible and can be placed  into a open hardware and software-based stack.

Advantages with virtualized 5G RAN

RAN virtualization presents numerous significant obstacles as the processing and timing needs are extremely high on particular functions in the lower parts of the RAN. These functions are crucial as lots of aspects of RAN coverage and capacity are handled by them.

Initially, a fully virtualized RAN (vRAN) could bring significant benefits of harmonization: one unique consistent hardware system throughout the RAN, Core network and also edge. This might simplify the management  of the overall network, reducing operations and also maintenance costs.

Second, in a full vRAN, the network functions and processing hardware will be divided. This indicates that RAN network functions from several vendors might operate on the exact same hardware, boosting the flexibility for the company.

Ultimately, a commonly adopted open platform can additionally reduce barriers for cross-domain innovation, promoting the development of brand-new use cases as well as services.

Open interfaces in Virtualized RAN

Work is ongoing with  the O-RAN Alliance on the advancement of specs for open network user interfaces.

There is an article in our website giving more information on the O-RAN which will allow the operator way instead of “vendor way”

Virtualization and also open RAN interfaces as specified by 3GPP and the O-RAN Alliance are typically discussed in the very same context, although they are mutually independent. From a technological point of view, open interfaces can be realized on both traditional purpose-built and brand-new COTS-based systems.

Any type of Worries about the Split in RAN ?

Followings are some of the commonly raised concern related to RAN virtualization:

Performance issue: Even though we see ever boosting performance of those open hardware (e.g, HP/ DELL Server) in one side, we see ever raising requirement of throughput and latency on the other side (i.e, throughput and also latency requirement recommended in NR). The concerns is whether the speed of the open hardware evolution is fast enough  to catch up the speed of the requirement evolution.

Taking responsibility : In deploying split architecture , it is extremely most likely that the hardware (i.e, web server) as well as software originates from different suppliers. Then an important concern would appear. Who is going to be responsible  if any issue occurs?

No matter exactly how virtualization is accomplished, as the software and hardware are not always aggregated by a network supplier, these systems will certainly necessitate new business models with plainly defined responsibility and accountability. We would be experiencing a lot of ping-pongs amongst different stakeholders (i.e, Network Operators, Equipment vendor, software program vendors).

Security Issues: Whenever we discuss ‘open system and software program based system there is always concern about security.