# Open RAN Integration: Run ## White Paper April 2020 --- # Executive Summary The Open RAN concept and movement is not new – mobile operators and network and technology vendors have been developing solutions, conducting trials and deploying networks for the last few years. The important point is that Open RAN networks are being deployed today by major operators around the world – this is no longer a science experiment. The Open RAN concept is about disaggregating the RAN functionality by building networks using a fully programmable software-defined mobile network solution based on open interfaces – radios, base stations, etc. – that runs on commercial, off-the-shelf hardware (COTS) with open interfaces. There are two main organizations driving Open RAN: § OpenRAN refers to the project group that is a part of the Telecom Infra Group (TIP) whose main objective is the deployment of fully programmable RAN solutions based on GPPP/COTS and disaggregated software. § The O-RAN Alliance is the other main driver of the Open RAN concept, focused on efforts to standardize interfaces. The alliance was founded in 2018 by AT&T, China Mobile, Deutsche Telekom, NTT DOCOMO and Orange. A recent important step in the development of the Open RAN ecosystem was an alliance agreement between the two organizations. The new agreement allows the two groups to share information, reference specifications and conduct joint testing and integration efforts. Open RAN software and hardware vendors have been developing network solutions for the last few years. As part of the research for this paper, iGR identified 22 publicly announced MNOs around the world using equipment from multiple vendors, including Altiostar, Mavenir and Parallel Wireless, who had deployed Open RAN in commercial networks. These MNOs have collectively just over 1.199 billion subscribers in their commercial networks and operate in countries or regions with a total population of more than 2.4 billion. This means that these operators are responsible for 21.8 percent of the world’s mobile subscriber base. Furthermore, assuming the current trials convert to commercial deployments, iGR estimates that by 2024, Open RAN will be used by MNOs that collectively are responsible for 47.2 percent of the global subscriber base. ## What is Open RAN? Fundamentally, the Open RAN concept is about building networks using a fully programmable software-defined radio access network solution based on open interfaces – radios, base stations, etc. – that runs on commercial, off-the-shelf hardware (COTS) with open interfaces. Traditionally, mobile networks have been built with closed, proprietary software and purpose-built hardware. But today, mobile networks can be disaggregated and based on the Open RAN concept. In this context, disaggregation means separating the hardware from the software. The 3GPP introduced this concept in Release 14 of its specification with the Control and User Plane Separation (CUPS) of evolved packet core (EPC) nodes and the O-RAN Alliance produced the Open RAN specifications. With 5G New Radio (NR) in 3GPP Release 15 and beyond, this split is continued with the Service Based Architecture (SBA). 5G NR further abets disaggregation by continuing the split between control and user plane all the way down into the 5G base stations and radios with the central unit and distributed unit. The main reasons to move away from the old, vertically integrated model to the Open RAN concept are those that drive virtualization of data centers and enterprise networks and the disaggregation of hardware and software: § Take better advantage of the rapid advances in computing power delivered by Moore’s Law. The data center industry experienced a similar disruption back in the 2000s. § Use software components to not only implement core network, radio and base station functionality, but also introduce new capabilities as they are developed. § Use best of breed components and software in architecting building the infrastructure for the network. § Enabling edge centric architecture – multiple mini data centers can be built closer to subscribers, especially in high population areas, to serve subscriber needs, support low latency connectivity for 5G applications and provide scalability for both devices and applications. ## The Open RAN ecosystem There are two main organizations driving Open RAN movement: § OpenRAN refers to the project group that is a part of the Telecom Infra Group (TIP). The main objective is the deployment of fully programmable RAN solutions based on GPPP/COTS and disaggregated software so that operators and vendors can benefit from the flexibility and faster pace of innovation capable with software-driven development. § The O-RAN Alliance is the other main driver of the OpenRAN concept, especially the efforts to standardize interfaces, in addition to the TIP. Founded in 2018 by AT&T, China Mobile, Deutsche Telekom, NTT DOCOMO and Orange, the O-RAN Alliance’s goal is to foster the development of reference designs and standards such that current and future RANs can be built with “virtualized network elements, white-box hardware and standardized interfaces that fully embrace O-RAN’s core principles of intelligence and openness.” (Note: The O-RAN Alliance was created by merging the C-RAN Alliance and the xRAN Forum.) A recent important step in the development of the Open RAN ecosystem was an alliance agreement between the two organizations to ensure they were in alignment in developing interoperable, disaggregated and Open RAN solutions. The new agreement allows the two groups to share information, reference specifications and conduct joint testing and integration efforts. ## Virtualization and openness It is important to understand that virtualization and openness are not the same thing. Virtualization is disaggregation of hardware and software by abstracting the software application from the underlying hardware. A RAN can be virtualized but not be open – i.e., the software and/or the hardware could be proprietary, or the interfaces could be closed. Being truly “open” means that there are reference designs and standards for hardware and software such that there are open interfaces with no proprietary interfaces and/or hardware in the RAN. For example, a COTS remote radio head/unit (RRH/U) from Vendor A will be able to talk via open interfaces to (proprietary) software running on a COTS server with (virtualized) network functions from Vendor B. Note that openness does not mean that all hardware and software will be the identical for all mobile networks. Vendors will compete to produce all of the hardware and software such that operators will have a broad selection in terms of scale, scope, features and cost. Due to the open interfaces and standardized hardware, the network software will run on COTS and talk to hardware and software from other vendors. This will lead to a wider procurement ecosystem from different vendors. ## Open RAN components The goal of this paper is not to describe in detail the technologies involved in Open RAN – the various technologies and architectures are complex and difficult to cover in a short white paper. There is a range of network architectures that are needed to address the specific needs of different mobile operators around the world and it is expected that vendors will interoperate to create customized solutions to meet these requirements. Moving forward into the world of 5G NR which, in 3GPP terms are Release 15 and beyond, the specifications require the RAN to become a new, disaggregated grouping of functional elements (as has been discussed earlier in this paper). The 5G base station, known as the gNB (as opposed to the eNodeB or eNB in LTE), is comprised of several functional units: § The radio unit (RU) which comprises the RF chain, to transmit or receive the over-the-air signal and provide corresponding transformation of the analog radio signal and the digital signals. § The distributed unit (DU) which handles the lower layers of the baseband processing up through the PDCP layer of the protocol stack. In legacy systems, this runs on a proprietary hardware appliance, but today’s software (which runs on COTS) allows this function to be virtualized. Since it is virtualized, this gives flexibility in terms of placing the processes at different locations which may include the cell site, far edge locations and/or the centralized locations. These functional splits are defined in the 3GPP specifications and their placement is selected based on type of transport available to the cell sites. § The centralized unit (CU) handles all higher layer functions of the protocol stack from PDCP and above. As has been stated, the goal of Open RAN is to create open interfaces so that the hardware and software from different vendors can interoperate and talk to each other. One key initiative is the TIP Evenstar program which has developed a Remote Radio Head (RRH) that will be available in the second half of 2020. The Evenstar RRH decouples the base components of the RRH and will support the O-RAN Central Unit-Distributed Unit (CU-DU) architectural split known as 7.2. Beyond this, other vendors including MTI, Gigatera Communications, NEC, Airspan and Fujitsu have announced that they plan to provide radios in various configurations which will adhere to Open RAN specifications. ## Industry challenges that drive Open RAN The legacy RAN vendors have provided solutions that are proprietary and siloed for each air interface generation. By virtue of their established base of traditional mobile operator radio infrastructure, these vendors may position themselves to provide some of the benefits associated with virtualization and they may comply with the 3GPP release specifications, but they are not required to open up their hardware/software interfaces to other equipment vendors. Therefore, they continue to promote and provide only closed, proprietary systems that are only in their best interests and not creating a future-proof network for their operator customers, although it is completely within their capabilities today. In some cases, the legacy OEM’s reluctant decision to open up any part of their hardware/software architectures has been driven by the requirements of some of their incumbent mobile operator customers. In part, one of the drivers for Open RAN has been the need to expand the radio ecosystem – the reality is that there are relatively few radio vendors available today. The radio is one of the most important components in a mobile network, it provides the link between the subscriber and the network and is therefore widely deployed. Growing the radio ecosystem is therefore seen as important for the success of the Open RAN movement. ## Benefits of Open RAN From the mobile operator’s point of view, benefits of Open RAN include: - Lower costs – both CapEx and OpEx - Lower deployment times – Using virtualized RAN, benefits like automation can reduce the average time for deploying a site. - Upgrade options from multiple vendors to future-proof the network evolution. - Minimizes the danger of vendor lock-in. - Easier to scale because disaggregating hardware from software can enable carriers to respond more quickly. - Ability to add massive scale if needed using web scale approach. The last bullet highlights one of the main architectural benefits of Open RAN networks. Since edge computing is being deployed by mobile operators around the world, the edge compute architecture can be used for Open RAN – containers can be used to push changes (using automation) to the network, using the DevOps model. In addition, to further support mobile operators as they transition to 5G, Open RAN also supports legacy 2G, 3G and 4G LTE network technologies. Moving forward, the need to continue supporting LTE while also transitioning to 5G adds more complexity to an already complex RAN. Not only will carriers be introducing new frequency bands (such as mid-band/CBRS and mmWave), layering in new carrier aggregation schemes, adding small cell sites, adding capacity to macrocells, coordinating capacity among small cell sites and macrocells, swapping out old antennas for new, they will also need to support edge computing solutions and new applications – VR/AR, IoT, etc. Opening up the RAN so that operators can introduce comparatively less expensive COTS and best-of-breed software can help operators’ future proof their networks and become more flexible in their operations. # Open RAN integration Open RAN is being deployed in multiple markets by multiple MNOs around the world. They are large scale deployments in some of the largest countries in the world. It is important to understand there are two levels of integration required when discussing Open RAN networks: - Open RAN ecosystem integration includes the hardware, software, systems integrators, data centers and MNOs. In this case, the systems integrator will be responsible for integrating across the entire solution including integrating open radios. - System integration of the Open RAN software on COTS hardware. This level of integration is similar to what occurs in the data center environment. Systems integration can be provided by a variety of companies and can be provided by one vendor if needed. This situation is similar to what the MNOs use today – there is no reason that Open RAN cannot be as simple and easy to integrate and deploy as the RAN is today. Despite this activity, many of those critical of the open network movement and trying to preserve proprietary systems still present arguments against Open RAN – these are old arguments that were leveled in the past but are no longer relevant. ## Table 1: Easy to Counter – the arguments against Open RAN integration | | OLD ARGUMENT | DETAIL | CURRENT SITUATION | |---|--------------|-------|------------------| | 1 | Since multiple vendors are required for an Open RAN deployment, the solution is not integrated | Numerous Open RAN deployments in live MNO networks are integrated | | 2 | High risk for network reliability | Open RAN network deployments have demonstrated ability to support large subscriber bases and meet network performance KPIs. | | 3 | Lower overall network performance | Real world Open RAN deployments have demonstrated ability to support large subscriber bases and meet network performance KPIs. | | 4 | Lower CapEx solution cost savings not realized | Actual Open RAN network deployments by multiple MNOs have resulted in significantly lower costs-both CapEx and OpEx. | | 5 | Overall costs higher than traditional | Actual Open RAN network deployments by multiple MNOs have resulted in significantly lower costs – both CapEx and OpEx. | | 6 | Systems integration lacking | Multiple MNO deployments show that different software components have been integrated. | | 7 | Less secure | Open RAN deployments have followed data center, private cloud, and enterprise IT integration and security best practices | | 8 | Ecosystem not developed to support MNOs | Open RAN now supported and deployed by some of the largest hardware and software vendors in the world. | | 9 | Only suited to greenfield MNO deployments | Multiple MNO deployments show that Open RAN can support legacy technology networks as well as new 4G LTE and 5G deployments. | # Open RAN Case Studies Open RAN software and hardware vendors have been developing network solutions for the last few years (the OpenRAN Project Group was launched by the TIP at the TIP Summit in November 2017). After several trials, there are a number of commercial deployments with many more in the pipeline, as well as numerous trials by major national and multi-national MNOs. As part of the research for this paper, iGR identified 22 publicly announced MNOs around the world using equipment from multiple vendors, including Altiostar, Mavenir and Parallel Wireless, who had deployed Open RAN in commercial networks. This section details some of the major Open RAN deployments around the world. ## Vodafone Vodafone has been heavily engaged in Open RAN efforts from the start of the initiative. The multi-national operator has stated that it has three main goals for its Open RAN involvement: - To spur innovation through building an ecosystem, - To enable supplier diversity and, - To reduce deployment and maintenance costs. Vodafone recently noted that “the global supply of telecom network equipment has become concentrated in a small handful of companies over the past few years. In Turkey, Vodafone was able to modernize its network with Parallel Wireless using the Open RAN architecture. ## Rakuten In 2019, Rakuten was the first to implement a multi-vendor RAN, using products from Altiostar, Airspan, Nokia and others. Rakuten’s network began as an LTE network consisting of both macro and small cells. Rakuten’s network is a text book example of how cloud, virtualization and vRAN architectures and practices can be applied to a new network deployment. ## IpT Internet para Todos Perú (IpT Peru) launched in May 2019. With the Parallel Wireless OpenRAN Controller, IpT has created a multi-vendor, multi-operator, open ecosystem of interoperable components for the various RAN elements and from different vendors. ## MTN MTN plans to deploy Open RAN technology at more than 5,000 rural sites in Africa across their 21 operations in order to bring mobile connectivity to those regions. # Open Test and Integration Center In September 2019, the Open Test and Integration Center (OTIC) initiative was launched by a group of global operators, vendors and systems integrators. The OTIC was founded to facilitate OEM and other open source products and solutions to be functionally compliant to the specifications of the O-RAN Alliance, through verification, integration and testing of disaggregated RAN components and to deliver the desired architecture that supports a plug-n-play model. The initial focus is to ensure that RAN components from multiple vendors support standard and open interfaces and can interoperate in accordance with O-RAN test specifications. # Vendor profiles This paper was sponsored by Altiostar, Mavenir and Parallel Wireless. A brief overview of each company is provided here. ## Altiostar Altiostar provides a 4G and 5G virtualized RAN software solution that supports open interfaces and disaggregates the hardware from the software to build an open multi-vendor web-scale cloud-based network. ## Mavenir Mavenir accelerates and redefines network transformation for Service Providers by offering a comprehensive product portfolio across each layer of the network infrastructure stack. ## Parallel Wireless Parallel Wireless is a U.S.-based company challenging the world's legacy vendors with the industry's only unified ALL-G (5G/4G/3G/2G) software-enabled Open RAN solution.