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What is a RAN Intelligent Controller (RIC)?

The RIC is cloud software responsible for controlling and optimizing baseband communication functions on the RAN

The RIC is a key element in the management of 5G network functions like network slicing, high-bandwidth, low-latency applications, prioritized communications and more. 

The RAN Intelligent Controller (RIC) is an essential component of the Open RAN architecture. The RIC architecture includes a Distributed Unit (DU) software function, multi-RAT CU protocol stack, a near-real time RIC and orchestration/NMS layer with Non-Real Time RIC. 

The functionality of the RIC is implemented as Virtual Network Functions (VNFs) or containers in cloud computing. These software functions interact with Radio Unit (RU) hardware for maximum RAN optimization and efficiency.

RIC design 

The RIC comprises both non-real-time (non RT) and near-real-time (near RT) components, both of which manage separate functions of the RAN. The non RT RIC manages events and resources with a response time of one second or more. The near RT RIC manages and events and resources requiring a faster response down to 10 milliseconds (ms). The non RT RIC is deployed centrally, while the near RT RIC can be deployed centrally or on the network edge. 

The non RT RIC operates from within the RIC’s Service Management and Orchestration (SMO) platform, so it handles lifecycle management for all network elements, configuration management, and many other essential network functions. The Non-RT RIC optimizes RAN functions by providing policy-based guidance, model management and enrichment information to the near-RT RIC function.

The near RT RIC controls RAN infrastructure at the cloud edge. 

rApps are specialized microservices operating on the non RT RIC which provide essential control and management features and functionality. xApps are hosted on the near RT RIC.

RIC specifications and management

The features and functionality of the RIC — and RAN disaggregation in general — are spelled out in 3GPP’s Release 15. The O-RAN Alliance operates several technical workgroups responsible for shaping different elements of the Open RAN specification.

Guidance for the RIC specification falls under the aegis of O-RAN Workgroups 2 and 3. Those are the Non-real-time RAN Intelligent Controller and A1 Interface Workgroup and the Near-real-time RIC and E2 Interface Workgroup, respectively.

RAN Intelligent Controller (RIC) in the news

The O-RAN Alliance published a set of Open RAN technical specifications in October that includes the initial version of its Non-Real-Time RAN Intelligent Controller (RIC) Architecture.

VMware has announced a RIC for its Telco Cloud Platform. VMware RIC uses Intel’s FlexRAN reference architecture. VMware anticipates a 2022 release of VMware RIC following a developer ramp-up in late 2021.

NEC and NTT DoCoMo announced a RIC collaboration in June. The two companies said they are aiming to reduce RAN operational costs, improve performance and reduce power consumption through the use of RIC software. The RUs will conform to O-RAN fronthaul interface specifications defined by the O-RAN Alliance and will be compatible with base station equipment from different vendors.

Deutsche Telekom and the Open Network Foundation (ONF) have launched a software-defined WAN (SD-WAN) trial in Berlin. The trial integrates components from eight companies: AirHop, Edgecore, Facebook, Foxconn, Intel, Radisys, Supermicro and Wiwynn. Additionally, the Telecom Infra Project (TIP) is participating by providing hardware and facilities out of the TIP Community Lab in Berlin, hosted by Deutsche Telekom.

The live 4G/5G trial features horizontally disaggregated hardware (separate RU, DU and CU units), as well as vertically disaggregated software components including an open source near real-time RIC (nRT-RIC) and xApps coming from the ONF’s SD-RAN project.

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