Open RAN explained

Open RAN explained

The acronym O-RAN (Open Radio Access Network) represents the concept of an open radio access network (RAN) with standardized RAN elements that are interoperable, including a uniform networking standard for hardware without proprietary software, as well as open-source software elements from various suppliers. The Open RAN architecture combines base station software modules with commercial off-the-shelf hardware so that baseband unit (BBU) and radio components (RRU) from multiple suppliers communicate smoothly with each other.

The Open RAN reinforces 5G’s more demanding RAN performance goals by providing uniform standards for efficiency, intelligence, and versatility. The O-RAN, installed at the network edge, benefits applications of the Internet of Things (IoT). It also effectively supports network slicing and allows secure and efficient firmware upgrades over the air interface.

Currently, Radio access networks are closed systems

A radio access network includes base stations and the technology to communicate (a connectivity protocol) with the core network. The central hardware components of a base station are the radio unit, which generates the radio signals for transmission and receives radio signals from the terminals, and the baseband unit, which is connected to the core network and digitally processes the data to be transmitted and received. Currently, the respective RAN architecture is a closed system and characterized by vendor-specific hardware and software, which operate with vendor-specific interfaces and functions in addition to standardized interfaces and functions. The processors used in the radio units, so-called single-purpose processors, thus operate very efficiently and with low energy consumption. At the same time, being overly dependent on specific systems and manufacturers can be problematic. This is an issue that also plays a central role in the current debate on 5G network deployment.

The current RAN architecture also requires extensive replacement or rebuilding of hardware in order to introduce a new mobile communications standard, which is due to the fact that each mobile communications standard requires a specific combination of hardware and software. For example, for a base station to cover UMTS as well as LTE, it currently has to be equipped with different technology for each of the two standards.

What is the O-RAN Alliance?

The Open Radio Access Network Alliance was founded in 2018 by an international syndicate of network operators, to further deploy RAN networks around the world. This goal can be achieved with the transition to virtualized network elements, white-box hardware, and open interfaces to the RAN.

The O-RAN Alliance relies on the interlocking concepts of openness and intelligence and has established eight different working groups pursuing ambitious technical projects. These include an open fronthaul architecture, moving the RAN to the cloud (”cloudification”), and developing the software specifications for the New Radio (NR) protocol stack.

Benefits of Open RAN explained

Previous RAN initiatives, such as cloud RAN (cRAN), have already enabled operators to boost the efficiency of their operations while still remaining reliant on individual equipment suppliers. With its new open, vendor-independent RAN ecosystem, the O-RAN introduces cloud-based cost benefits and more competition to the RAN. In conjunction with a more agile and flexible RAN architecture, which is already taking shape with virtualization, market forces are enabling much shorter time to market than ever before.

By moving away from a vendor-dependent RAN approach, network operators can be more flexible. It also avoids the ”hidden characteristics” that cause them to remain dependent on a specific vendor for all aspects of implementation and optimization.

The increasing competition with the new participants in the market, and the greater diversity that comes with it, can reduce equipment costs in the O-RAN. It is also possible to leverage the beneficial interoperability between network operators in the O-RAN to increase the efficiency of existing LTE networks as they continue to implement the virtualization and disaggregation that are essential to the deployment of the 5G RAN.

Three major benefits in a nutshell:

  1. O-RAN can drastically lower capital expenditure:
    1. The open interface facilitates multi-vendor cooperation, allowing for healthy competition amongst suppliers.
    2. Since both hardware and software are open source, innovation can be achieved much faster due to the ease of collaboration between developers.
    3. O-RANs native cloud feature provides scalability.
  2. O-RAN lowers operating expenses: Every network layer of the RAN architecture can feature embedded intelligence provided by O-RAN. These AI learning based technologies enable the automation and optimization of various network functions, thus reducing the overall operating expenses.
  3. Better network efficiency: Inherently, O-RAN will be able to provide optimized, efficient resource management by conducting real-time close-loop control with little to no human intervention. This can greatly elevate network performance and, consequently, the network user’s experience.
  4. Can adopt new network functions: Its native cloud infrastructures allow O-RAN to swiftly import newly developed network capabilities.

Challenges of O-RAN

To deliver seamless interoperability in an opened multivendor ecosystem, new testing, management, integration and compatibility challenges need to be addressed. This goal cannot be achieved without close cooperation and great care. In the single-vendor model, responsibility is obvious and problem containment and troubleshooting is governed by a defined command structure.

With multiple providers, on the other hand, it could be problematic to track down who is really responsible for the fault if the actual cause of the fault cannot be accurately determined. The same complications could arise in enforcing product launch deadlines and revenue growth, as management and coordination responsibility is spread across several different O-RAN stakeholders and thus diluted.

Furthermore, the tantalizing O-RAN concept places new demands on testing and integration. To achieve the reduction in operating expenses and total cost of ownership promised by the O-RAN, network operators must take responsibility for individual elements originating from multiple vendors and ensure that they work smoothly with each other to meet the required quality of experience (QoE).

Joint initiatives among network operators, such as the Open Test and Integration Center (OTIC), can help facilitate standardization of component, software, test, and technology development for O-RAN across the industry to prepare for widespread practical O-RAN deployment.

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