A key element in the open RAN technology stack is about to get a workout during 2022. And, if it performs as open RAN proponents expect, the RAN Intelligent Controller (RIC) could hit the mainstream in the coming years.

And that's critical to mobile network operators because RICs could ultimately support the development of new applications and services for network operators embracing open RAN.

But first, RICs must be tested. According to Heavy Reading analyst Gabriel Brown, operators this year will likely be testing the technology in the field. He doesn't expect full-blown products until the end of this year at the earliest. Vendors in the space range from Juniper Networks to VMware to some open source offerings from the likes of the Open Networking Foundation (ONF).

RICs could eventually replace self-organizing networks (SON) in classic RAN architectures. RICs help control base stations from a variety of vendors. Specifically, they can support various dynamic networking features such as switching off radios during non-peak times to cut energy costs.

And RICs are key to open RAN technology. Open RAN promises to allow network operators to mix and match network elements from different vendors rather than being locked into a tightly integrated stack of components supplied by just one vendor.

RICs come in two flavors: near-real time RICs and non-real time RICS. Brown expects most of the early RIC deployments to be of the non-real time variety because those specifications are farther along and less tightly coupled with the control of baseband scheduling.

Interestingly, RICs can be further divided into centralized, non-real-time RICs (C-RICs) and distributed near-real-time RICs (D-RICs). Omdia analyst James Crawshaw said the C-RIC is higher up in the network architecture, which gives it a broader view of numerous cell sites across a given region.

D-RICs, meanwhile, are closer to the radios themselves. D-RICs "are going to be able to do more real time stuff because they're physically closer. But they're only going to be controlling maybe one radio tower, or maybe five radio towers, and not 50," Crawshaw said.

Thus, operators will need to decide exactly which configuration will be best for their network. Some are already doing just that.

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For example, BT recently announced it was conducting a non-real-time RIC trial with Nokia in the UK city of Hull over BT's EE mobile network. BT Chief Architect Neil McRae said the operator is currently testing various RIC applications (rApps and xApps in industry parlance). "We're working mostly on network optimization apps focused on getting the best experience from our spectrum bands, but in addition we're looking at how we use this to put the network in a specific area into different modes," McRae wrote in an email to Light Reading.  The modes could include "large event mode" or "low power mode," among others. 

A separate RIC test involves Deutsche Telekom's field trial of ONF's RIC software platform. The operator's 4G and 5G Standalone (SA) outdoor trial is live on Deutsche Telekom's network in Berlin, Germany.

Still another test, announced last year by Vodafone, involved doubling the capacity of a 5G cell site by using a RIC in tandem with multiple vendors, including Capgemini Engineering, Cohere Technologies, Intel, the Telecom Infra Project (TIP) and VMware. According to a Light Reading webinar, the trial included a demonstration of 5G MU-MIMO control using a near-time RIC where the MU-MIMO control-plane algorithms for user pairing and precoding were delivered by a third party as an xApp.

Despite the promise of the RICs, Brown said there wouldn't be a rush of commercial product launches. Instead, this year is more likely to see pre-commercial field trial deployments. Classic RAN will also be in play for many more years, which means operators and vendors will need to coexist in a hybrid world of traditional and open RAN.

And SON isn't going away anytime soon, according to Crawshaw. He said the traditional SON market will be flat in 2022, but expects it to go into decline from 2023 onwards as spending shifts towards the open RAN-based RIC, according to Crawshaw's research. Overall, the research forecasted growth of 10% to 25% each year from 2022 to 2026 for the combined SON and RIC market. 

"This is just analyst's guesstimate, but we guess this, this SON plus RIC plus apps market grew by 4% last year" Crawshaw said. "This year, it will grow 14%, and next year it will grow to 18%. And thereafter, 2024 might be the peak growth for RIC plus the apps, but we could be too early on that."

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— Mike Robuck, contributing editor, special to Light Reading