Things are happening fast in efforts to make the fully cloud-based Radio Access Network (RAN) a reality for 5G. An important new development is Nokia’s work with AT&T to jointly create the Radio Edge Cloud (REC) with the aim of releasing it in open source through the Linux Foundation.
But what, you may be asking, is the REC? REC is a lightweight and robust telco-grade appliance built to provide real-time provisioning and scalability for low latency applications. A prominent example of such an application is the near real-time RAN Intelligent Controller (RIC), which is a new network element that enables external applications to control aspects of the 5G radio network (see AT&T and Nokia Accelerate the Deployment of RAN Open Source).
REC is the first example of the Telco Appliance blueprint family which provides reusable modules for creating blueprints for other specific appliances. The REC will include automated configuration and integration testing of the full stack starting from below the OS layer, up through RIC (from https://gerrit.o-ran-sc.org/r/admin/repos ). As part of the Telco Appliance blueprint family, REC will share many hardware and software components, including installation, configuration management and APIs with other family members.
AT&T and Nokia turning vision into reality
5G network architecture offers flexibility through several network implementation options. But this increases the complexity of the network, particularly using arrays of antennas (MIMO) for dynamic beam tuning. Such beam steering even makes it possible to follow individual users to provide them with the best possible connectivity. Furthermore, 5G’s use of higher frequencies means cell sizes will be smaller, requiring more antennas.
Nokia, together with the O-RAN Alliance, is tackling this with new network elements (such as the RIC) and new interfaces, like E2 from RIC to the baseband units. The RIC will provide added-value to the RAN via xApps that run in containers. Each RIC will have low latency connectivity to many baseband units so that xApps can provide a level of control that spans many separate radios, while still delivering the low latency needed to respond to near instantaneous changes in the mobile environment.
AT&T and Nokia are working together to make this vision into reality, using open source as a tool. The xApps will run on the RIC platform which is developed in the O-RAN Software Community (link here). The RIC platform itself uses the Radio Edge Cloud (REC) blueprint, part of the Telco Appliance Family in the Akraino project.
With the focus on edge clouds, Akraino is a natural place for REC, which requires a telco-grade platform and support for Kubernetes containers, as a modern software development platform. Nokia is bringing its experience in building robust telco systems, while AT&T is providing the carrier grade capability to operate and deliver the service.
The key attributes of the REC will include:
- Specific hardware configurations automatically tested via continuous deployment automation. Multiple hardware variations may be tested in parallel, but each tested configuration will be fully specified and reproducible.
- Specific pre-boot software (e.g. firmware/BIOS) will be specified as part of the CD tested configuration.
- Reproducible software installation and configuration to allow deployment of large numbers of sites with versioning traceable back to automated CD testing.
- Modular building blocks assembled and tested (via CD automation) to ensure a guaranteed level of performance of the target application, while allowing other members of the family to assemble and tune the modular building blocks for other target applications.
- Good design will help to ensure future extensions to integrate RIC and other applications, but still in an appliance with tested/guaranteed performance of the combined application set.
By standardizing the interfaces and the runtime environment we are enabling the creation of innovative xAPPs with interoperable control plane logic to optimize radio resource utilization and provide services which are based on rapid response to changes that span multiple radio coverage areas.
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