Altiostar Conducting O-RAN Compliant 5G Massive MIMO Technology Interoperability Testing in Cooperation with NEC and Rakuten Mobile

First successful multi-vendor O-RAN interoperability testing for massive multi-input, multi-output (mMIMO) 5G Radio Units with vRAN

TEWKSBURY, MA — May 19, 2020 – Altiostar today announced testing of the industry’s first O-RAN Alliance-compliant multi-vendor massive-multi-input, multi-output (mMIMO) 5G with vRAN in collaboration with NEC Corporation and Rakuten Mobile. Interoperability based on open specifications from the O-RAN alliance opens the door for operators to leverage a diverse ecosystem and ensures modularity while deploying their networks.

Altiostar is integrating the O-RAN Distributed Unit (O-DU) functionality of its virtual radio access network (vRAN) software with NEC’s O-RAN Radio Unit (O-RU) using fully compliant control, user, synchronization and management (C/U/S/M) plane protocols based on O-RAN Alliance guidelines. The 5G layer is built using container network functions (CNF) that leverage Rakuten Mobile’s cloud infrastructure platform that is part of its 4G network build out.

As part of management-plane integration, Altiostar is following a hierarchical model that allows the O-DU software to manage the NEC O-RU, including providing software upgrades, RU configuration, fault management and performance monitoring. This interoperability is being performed for 5G new radio (NR) sub-6 GHz massive MIMO O-RU and meets all the 3GPP downlink/uplink (DL/UL) requirements.

Altiostar has pioneered RAN disaggregation since 2013 when it first introduced a split between the higher non-real-time layers of the protocol stack and the lower layers of the stack. The industry then standardized this concept in the 3GPP and what is now known as the option-2 split between the centralized unit (CU) and the distributed unit (DU). This paved the way for operators to think differently when it comes to disaggregation and network deployment.

Further disaggregation was introduced by Altiostar in the form of a radio interface unit (RIU). The RIU incorporates lower L1 functionality and provides a gateway function that converts Common Public Radio Interface (CPRI) to/from Ethernet.  By eliminating the high bandwidth and proprietary CPRI interface to the radio, Altiostar took a quintessential step towards integrating legacy Remote Radio Head (RRH) over an Ethernet transport network to O-DU functionality.

Using this technology, the first multi-vendor RAN was deployed at a commercial scale and paved the way for operators to engage radio vendors to build O-RAN compliant radios. The bold step taken at Rakuten Mobile has driven the RAN ecosystem to adopt open interfaces offering operators a wide variety of options in building out their network.

“Open RAN as a concept is one that the whole industry is now actively pursuing as a means to introduce supply chain diversity into mobile networks globally,” said Ashraf Dahod, CEO of Altiostar Networks. “Altiostar is leading the industry with this network transformation by ensuring interoperability, integration and most importantly extensive testing to ensure that we have a commercial, carrier-grade solution for both 4G and 5G while keeping the principles of Open RAN in place.”

“Rakuten Mobile is a big supporter of O-RAN principles and has seen the benefit of supply chain diversity in our own network,” said Tareq Amin, Representative Director, Executive Vice President and Chief Technology Officer of Rakuten Mobile. “By combining the spectral efficiency of massive MIMO along with an advanced cloud-based RAN, we are leveraging and introducing advanced innovative technology from both NEC and Altiostar, who are specialists in these respective fields.”

Altiostar Solution

Altiostar has been a pioneer in developing O-RAN-compliant containerized 5G Open RAN solutions.

Altiostar’s container-based 5G solution splits the baseband into centralized units (CU) and distributed units (DU) using micro-services to disaggregate these RAN workloads at a deep level. The DU provided by Altiostar is interoperable with, and uses, O-RAN compliant interfaces to work with third-party O-RUs. These workloads can be deployed flexibly to support different quality of service (QoS) and other requirements of the 5G network slice.  The Altiostar containerized architecture also intrinsically introduces Control Plane User Plane Separation (CUPS). Thus, containers that support IoT can be sized differently when compared to other workloads, such as enhanced Mobile Broadband (eMBB) applications. Alternatively for ultra-reliable low latency communications (UrLLC) applications like V2x or augmented reality, the operator can dynamically deploy the user plane containers at far-edge locations.


NEC has designed its 5G Radio Unit (RU) as an active antenna array system (AAS) that consists of an RF front end and a massive-element antenna in order to minimize the system footprint and provide high-efficiency.

NEC’s AAS utilizes a fully digitized antenna beam control technology that improves the precision of beam forming. While transmitting beams to the target mobile handsets, it is capable of forming beams that counteract interfering signals using multi-path. It can also form beams that improve communication quality by efficiently combining the multi-path of its own signals with the direct waves.

The features of NEC’s AAS enable concurrent communication with several handsets, even though they are close to each other, while maintaining high communication quality. In the trials, NEC proved that use of the AAS can result in improved capacity and quality of communication between a base station and handsets, while confirming that spectral efficiency was reliably maintained at a level roughly eight times higher than that achieved by LTE in indoor environments.

About Altiostar

Altiostar provides 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 network.  This solution supports macro and small cells, indoor and outdoor, enabling interference management, carrier aggregation and dual reception to improve the efficiency of the network and enhances the Quality of Experience for the user while providing broadband speeds. Operators can add intelligence, quickly adapt the software for different services and automate operations to rapidly scale the network.

About NEC

NEC Corporation has established itself as a leader in the integration of IT and network technologies while promoting the brand statement of “Orchestrating a brighter world.” NEC enables businesses and communities to adapt to rapid changes taking place in both society and the market as it provides for the social values of safety, security, fairness and efficiency to promote a more sustainable world where everyone has the chance to reach their full potential. For more information, visit NEC at

Rakuten Mobile

Rakuten Mobile, Inc. is a Rakuten Group company responsible for mobile communications, including mobile network operator (MNO) and mobile virtual network operator (MVNO) businesses, as well as ICT and energy. Through continuous innovation and the deployment of advanced technology, Rakuten Mobile aims to redefine expectations in the mobile communications industry in order to provide appealing and convenient services that respond to diverse customer needs. For more information, visit