Frequently Asked Questions
What is the RAN and how does it factor into the mobile ecosystem?
The mobile ecosystem is comprised of four primary components: (1) end user devices, (2) the Radio Access Network or RAN, which consists of cell sites and their subcomponents such as radios, hardware and software, (3) the core network and (4) the applications that interact with end user devices. End user devices communicate with cell sites that are distributed across a geographic region and then connect to a core network via fiber backhaul. In traditional networks the core then connects to Internet to access applications. With the advent of 5G some of the core and application functionality will shift closer to end users, and in some cases be deployed on premises, providing the reduced latency benefits of 5G, as well as distributing the processing power to the network edge and customer premises depending upon the use case.
Why do most mobile network operators deploy their networks using a single vendor in a geographic region?
Mobile networks have typically been deployed using fully integrated cell sites where the radio, hardware and software are provided by a single manufacturer as a “closed” proprietary solution. The protocols and interfaces between the various subcomponents in the RAN, such as the radios, hardware and software, are private (either not standardized, or controlled by a single company), which means that, for example, a network couldn’t be deployed using radios from one vendor with RAN hardware and software from another vendor. This also means mixing and matching cell sites from different providers typically leads to a performance reduction. The result is that most network operators, while supporting multiple RAN vendors, will deploy networks using a single vendor in a geographic region.
What does it mean to “open” the protocols and interfaces between the various RAN subcomponents?
The key concept of Open RAN is “opening” the protocols and interfaces between the various subcomponents (radios, hardware and software) in the RAN. As a technical matter this is what the industry refers to as a disaggregated RAN.
There are three primary elements: (1) the radio unit (RU), is where the radio frequency signals are transmitted, received, amplified and digitized. The RU is located near, or integrated into, the antenna; (2) the Distributed Unit (DU) is where the real-time, baseband processing functions reside. The DU is located at, or near, the cell site; and (3) the Centralized Unit (CU) where the slower, packet processing functions reside. The CU is located deeper in the network near the core.
It is the interfaces between the RU, DU and the CU which are the focus of Open RAN. By opening and standardizing these interfaces, and incentivizing implementation of the same, we move to an environment where networks can be deployed with a more modular design without being dependent upon a single vendor.
Are there other groups working in this space to develop open RAN standards and protocols?
Yes. One example is the Open Radio Access Network Alliance (O-RAN) which was founded in 2018 or the Telecom Infra Project (TIP) founded in 2016 and chaired by Vodafone. There are currently 23 operators and 123 contributing members of the O-RAN Alliance all working towards open, interoperable interfaces in the RAN. TIP currently includes hundreds of members including project groups focused on Open RAN. The O-RAN Alliance and TIP recently announced a liaison agreement related to the development of Open RAN solutions. These two are not the only forum working in this space. Other examples include the Small Cell Forum. Management and orchestration of these open networks is being developed in the Open Networking Automation 2Platform (ONAP) which is being managed by the Linux Foundation. Another example is Open Radio Equipment Interface (ORI) which was standardized by European Telecommunications Standards Institute (ETSI) in 2014.
Does standardizing and developing open interfaces mean that vendor solutions themselves must be “open sourced”?
Open sourced is a software term where the original source code is made freely available and can be modified to form a software application. Open RAN doesn’t require open sourcing for software. By standardizing and developing open interfaces, we can ensure interoperability across different players and potentially lower the barrier to entry for new innovators. This does not mean that the vendor solutions themselves must be “open sourced.” It is likely that there will be blended implementations, leveraging open interfaces with specialized proprietary code while other aspects may be “open sourced.” The key to creating a vibrant marketplace is not how the implementation is done but standardizing the interfaces allowing a variety of different models to emerge and compete.
What specifically does Open RAN refer to, and how is it different from virtual RAN?
There are a lot of different terms currently being discussed in the industry. To help clarify, in this context, Open RAN refers to open and interoperable interfaces within and between the various subcomponents of the RAN. The radio, hardware or baseband unit and software. vRAN is a different concept where much of the RAN or network function is virtualized in software.
There is an ongoing move towards Software Defined Networking (SDN) and Network Function Virtualization (NFV) which take advantage of open and standardized interfaces. However, Open RAN and interoperable RAN interfaces and protocols don’t require that all elements in the RAN be software. In order to scale Open RAN and attract new entrants, protocols and interfaces need to be open, interoperable and standardized. Then what becomes software or “virtual” is an implementation issue that will be addressed by individual operators and their supplier partners.
What is the difference between Open RAN, O-RAN and vRAN?
Open RAN – disaggregated RAN functionality built using open interface specifications between elements. Can be implemented in vendor-neutral hardware and software-defined technology based on open interfaces and community-developed standards.
O-RAN – refers to the O-RAN Alliance or designated specification. O-RAN Alliance is a specification group defining next generation RAN infrastructures, empowered by principles of intelligence and openness.
vRAN – an implementation of the RAN in a more open and flexible architecture which virtualizes network functions in software platforms based on general purpose processors. vRAN utilizing open interfaces is one component of OpenRAN.
Are there any trials and implementations underway today?
Yes. There are several different implementations underway ranging from deployments to trials, demos and standards development activity supporting Open RAN. Examples include the following:
- Rakuten has deployed a commercial fully cloud-native mobile network with open vRAN in Japan, with radios from multiple vendors both in 4G and 5G.
- Altiostar has deployed its software with 4G/5G radios from Airspan, MTI, Nokia and Sercomm and is working with radios from Flex, Fujitsu, KMW, NEC and Xilinx to deploy by mid-year.
- On April 29, 2020, it was announced that India’s largest integrated telecommunications services provider, Bharti Airtel, had deployed Altiostar’s open vRAN solution across multiple major cities in India.
- Mavenir has deployed with Vodafone Idea and is partnering with Dish to deploy a fully virtualized nationwide network with Open RAN.
- NTT DOCOMO has already realized interoperability between base station equipment of Fujitsu, NEC and Nokia with O-RAN compliant fronthaul and X2 interfaces in their 5G commercial service.
- Telefónica has established an Open RAN consortium of hardware and software companies aimed for the development and deployment of open RAN in 4G and 5G, comprising the necessary design, development, integration, operation and testing activities required to materialize Open RAN.
- Parallel Wireless has been deploying Open RAN since 2015 with Vodafone, Telefonica, MTN, Optus, and is a strategic partner for rural U.S. operators and members of the Competitive Carriers Association (CCA).
- AT&T is one of the founding members and currently chairs the O-RAN Alliance. AT&T has also conducted several demos and trials including working with CommScope and Intel to demonstrate a mmWave 5G gNB and open front haul leveraging developments at O-RAN.
- Verizon is actively working with its current suppliers and smaller software developers to advance the open interface model.
- Vodafone is currently chair of TIP and has active trials of Open RAN ongoing in Turkey, Mozambique, DRC, Ireland and UK with Parallel Wireless and Mavenir.
- AT&T recently hosted the O-RAN Alliance Plugfest in New York City, where Samsung demonstrated the multi-vendor compatible Configuration, Performance, and Fault Management capabilities of the O1 interface.
- Telefónica conducted in 2019 successful open RAN trials in Brazil based on 4G, which are being evolved in 2020 to more ambitious 4G/5G trials that position ourselves towards 4G/5G commercial deployments.
- VMware, Inc. and Deutsche Telekom recently announced the companies are collaborating on an open and intelligent virtual RAN (vRAN) platform, based on O-RAN standards, to bring agility to radio access networks (RANs) for both existing LTE and future 5G networks.
When do you anticipate will be the pace of deployment?
As noted above there are some deployments underway today. We are likely to continue to see ongoing announcements about partnerships between various network operators and suppliers and expect to see a gradual deployment. The pace of deployment will depend upon a variety of factors including the extent to which the technology can be taken to scale and whether carriers and network operators can incorporate Open RAN into existing infrastructure and/or greenfield deployments.
Is there a security concern as communications networks evolve to be more like IT infrastructure?
In our view, the ability to have a more modular design, with different suppliers providing different components of the network will enhance, not diminish, security because it allows operators to more quickly react to replace or address suspect equipment. Further, a more intelligent RAN will enable operators to deploy security capabilities closer to the network edge allowing operators to more quickly respond and react to threats and shift network capacity on demand. Open architecture also allows operators to choose and apply up to date security patches available for Commercial Off the Shelf (COTS) components deployed in their networks (e.g., operating systems, NFV infrastructure, BIOS, firmware, etc.), and to address the security vulnerabilities pro-actively vs. being dependent upon individual vendors to make these updates. In the end, these developments, while different from traditional deployments, should improve network security.