Introduction
How disaggregation will impact network architecture and operator costs
What has been seen so far?
Radio access network (RAN) virtualisation and disaggregation promises opportunities to reduce cost and increase efficiency, capacity and interoperability for mobile networks. Under traditional network architecture, a RAN uses proprietary hardware (a remote radio unit (RRU)) attached to a mobile tower to exchange signals with user equipment. The RRU connects with baseband units (BBUs) comprising proprietary hardware and software that sends data between the base station and the operator's central unit (CU) or core network. RRUs, BBUs and their accompanying interfaces and software are proprietary to vendors and limited efforts have been made historically to ensure they are interoperable or can be componentised by operators.
How disaggregation will impact network architecture and operator costs
Virtual RAN (vRAN) disrupts this model by enabling operators to run baseband functions as software. vRAN, however, still requires proprietary, vendor-locked interfaces and hardware. Open RAN takes disaggregation a step further by facilitating non-proprietary RAN solutions on vendor-neutral platforms.
The key to enabling software and hardware disaggregation throughout the RAN is open, common interface protocols and hardware specifications all the way from the RRU to the CU. Common interface protocols mean operators are not locked to a specific vendor. This allows operators to mix and match different vendor solutions using cloud software on commercial off-the-shelf (COTS) server platform hardware to suit their needs.
Open RAN will also encourage supply chain diversity and resilience, provide scalability, and enable greater flexibility with interoperable solutions. Software based solutions allow operators to readily provide new services using primarily software updates without expensive physical deployments – for example, enabling Wi-Fi solutions in defined areas by adding a Wi-Fi enabled virtual network function. For further details on the development of common standards and protocols for mobile networks, including the latest standards supporting 5G, see "Non-terrestrial mobile networks – the final frontier for 5G?".
It is still early days for open RAN. Hard evidence for open RAN's benefits remains to be seen, with many operators hesitating against taking the first plunge. Some of the challenges are listed below:
- Widespread use of COTS hardware, while being a primary driver for adopting open RAN, will also introduce open platform management and integration challenges.
- Ensuring privacy, security and resilience will be more challenging for operators with a disaggregated network involving multiple solution vendors, heightening the importance and urgency to agree common standards and protocols.
- Open RAN deployment to high population centres requires mass adoption and adherence to commonly held standards to ensure end-to-end network performance, requiring high coordination between operators and COTS solution vendors.
- Vendor lock-ins reoccurring poses a risk to both the open RAN model and COTS suppliers. High integration costs expected for operators using a mix-and-match approach particularly in brownfields scenarios.
Many operators believe open RAN is the way forward to improve vendor competition, choice and interoperability, leading to more cost-effective RAN deployment options for operators. When and how this change will occur will depend on who is willing to make the leap.
For further information on this topic please contact Marcus Bagnall or Ben Towell at Wiggin by telephone (+44 20 7612 9612) or email ([email protected] or [email protected]). The Wiggin website can be accessed at www.wiggin.co.uk.