Near real time RIC and xApps market considerations

An extract from my upcoming report "Open RAN RIC and Apps 2023"   

As mentioned, near real time RIC and xApps capabilities are today embedded in gNodeB and RU/CU/DU code. The constraints of developing applications that have an actual effect in milliseconds on the RAN offer two main challenges, one technical, the second commercial.

The technical challenge associated with the development and roll out of xApps and the near real time RIC itself is related to the RAN Scheduler. The RAN scheduler, within the radio architecture is extremely processing intensive and is responsible, among other operations of the real time the uplink and downlink radio decoding and encoding.

Running concurrently with the L1/Phy, RLC and running on the MAC layer, the scheduler reads data from the upstream RLC and transmits to the downstream PHY. The scheduler effectively determines the number of bytes to transmit to each UE in real time.

Since the scheduler is in essence a real time forwarding engine, it is instantiated in the DU and the fronthaul connectivity should have less than 1ms latency to the RU. This stringent latency envelope requires extremely tight integration between the DU, the RU and the near real time RIC (and its associated xApps). While theoretically functionally feasible, the level of integration between all these vendors necessary to realize xApp with the appropriate level of control and performance is generally not there.

The vendors, naturally, first prioritize integration between their own products and in this case, the DU vendors are in control of that value chain.

Understanding that today, there is a very limited number of DU vendors, who are all in the process of realizing the O-RAN first generation implementation and integration, and understanding that all their resources are mobilized on commercial deployments where the priority is the functional, stable and performing implementation of RU, CU and DU, it is not a surprise that we do not see much multi vendor activity on near real time RIC, xApps integration with real RU and CU DU.

 

While we have several examples of trials with either non MIMO CU DU RU or proof of concepts with RU, CU, DU emulators, we are still far from real end to end deployment even in trial situation of a an end to end implementation close to commercial grade.

The second impediment to near real time RIC xApp multi vendor implementation is commercial and can be found in the report.

RICs and Apps executive summary

I first came across open RAN as a concept in 2016, as one of the teams I was supporting at Telefonica was looking into connecting the unconnected in Latin America. After ascertaining the demand, the primary problem to solve was affordability. It just wasn’t economical to deploy traditional RAN networks designed for dense urban environment in the middle of the jungle. The team came out with an interesting idea, the disaggregation of the RAN into components, allowing to pool resources and enabling multiple vendors to compete for different parts of the deployment.

After a few iterations and field trials, the team went on to write the first Open RAN RFI, jointly with Vodafone, released at TIP. From this idea, an ecosystem was born, with a community of operators and vendors, issuing specifications at the Open RAN alliance, elaborating and testing blueprints, issuing requirements and roadmap at the Telecom Infra Project and commercial deployments slowly spreading from Japan to Western Europe and North America.

As the first layer of disaggregation has split the gNodeB into the Radio Units, Centralized Units and Distributed Units, an ecosystem of vendors has emerged, addressing each or all the parts of this new architecture. That first layer of disaggregation was aimed at disrupting the traditional RAN ecosystem, breaking the oligopoly of vendors that have come to dominate the market.

The next stage of disaggregation is aimed at disrupting further the market, by introducing elements of vendor-independent centralized management, optimization, visualization and orchestration with the introduction of the Radio Interface Controllers (RICs). Two RICs have been defined, and although they share the same name, they are quite different in nature and ambition.

The non real time RIC is part of the Service Management and Orchestration layer and is the evolution of Self Organizing Networks (SON) and the RAN OSS / Element management. Features instantiated on the non real time RIC can be deployed as rApps, a standard-defined set of interfaces for multiple vendors to deploy.

The near real time RIC is a feature set belonging to the RAN layer and aimed at disaggregating it further. It extracts capabilities today embedded in the gNodeB, or the RU, CU, DU and provides a layer of abstraction and platform for multiple vendors to theoretically pilot and tune the Radio Network. xApps are the applications that can be developed to be deployed on near real time RIC.

From my experience at Telefonica, as an operator or at Bell Canada or Deutsche Telekom as advisor and consultant or from my time at NEC as global VP Product Management overlooking the development and partnerships surrounding open RAN products, or as an independent analyst researching the market, I have derived a unique perspective on the maturity and effectiveness of open RAN, RICs and Apps. 

This report examines the architecture, strength, drawbacks of open RAN RICs and apps as well as provides an inventory of the main players in the space.