The distributed unit (DU) is where the baseband computation and time sensitive front haul gets terminated in ORAN network architecture, with tens of thousands to hundreds of thousands of sites required for a nationwide network (depending upon spectrum and geographical area to be covered). With such massive scale of deployment, DU requires hardware that exhibit high capacity, lower footprint, lower power consumption, cost-effectiveness, hardened form factor and automation.
It was recently announced that Rakuten Mobile was the first Open RAN network to deploy 50,000 4G base stations. The Rakuten Symphony team has now brought that knowledge forward on the unique needs of the DU in Symware™, a first to market next-generation DU.
This week we announced the next chapter of the Symware story, which includes general availability for the appliance as well as a plan to deploy 30,000 units in the Rakuten Mobile network in Japan in the next 10 months.
The revolutionary nature of Symware lies in creating an appliance that optimizes each of the elements that are needed for successful DU deployments. Let’s take a deeper look at each of these:
Symware provides a computation platform for both DU software and also a virtual cell site router that eliminates the need for a separate router. Since Symware is a purpose built x86 platform, it acts as an application agnostic cloud platform as a built-in capability. With computational power (CPU cores), other cloud native network functions (CNFs) such as a user-plane function (UPF) could be run on the system.
Symware is truly agnostic when it comes to radio unit (RU) connections, supporting any RU that is Open RAN compliant. The server can also support both sub 6GHz and mmWave radio access technologies, as well as 4G and 5G networks.
"This week we announced the next chapter of the Symware story, which includes general availability for the appliance as well as a plan to deploy 30,000 units in the Rakuten Mobile network in Japan in the next 10 months."
The foundation of Symware’s cost effectiveness is the use of commercial off-the-shelf components from Intel. These are dramatically less expensive than custom ASICs and offer the performance required for processing RF signals. Using the server for multiple network functions dramatically lowers cost, but the biggest DU cost for MNOs are related to real estate and connectivity.
For every equipment deployed at the cell site, there is incremental rental cost. If a standard server needs to be placed in a temperature-controlled cabinet or shelter, that means extra cost. Symware is built with “Zero Footprint” site deployment in mind. Symware can also be deployed at top of the tower next to RU, as Symware has temperature hardened IP65 DU platform.
The other big cost is the connectivity. Ideally a dark fiber cable is used for connectivity between RU or Fronthaul Switch to nearest data center, where DU servers are deployed (in vRAN architecture), but there’s not always dark fiber near a DU location. Symware offers flexible network connectivity, supporting any available backhaul connection including IPMPLS, WDM, microwave and others.
Symware was developed in collaboration with Intel and features Intel technologies including the latest Intel® Xeon® D processors. These processors are designed for high performance in space and power-constrained environments – perfect for the fanless design of Symware. And with up to 20 cores, we’re able to create a cloud-native server that lets us run the DU software plus other network function software.
Because the DU primarily processes RF signals from radio units (RUs), Symware also utilizes Intel technologies to accelerate these workloads including FlexRAN™ reference software layer 1 stack and the Intel® Dedicated vRAN Accelerator ACC100 chip to handle forward error correction (FEC) acceleration for increased base station density and efficiency.
Symware is ready for any environment. With its IP65 ruggedized case and fanless design, the DU can endure the precipitation, temperature swings and wind. The DU weighs just under 41 pounds (18.5kg) and is designed to be installed by a single person at a remote cell site. The energy efficient design consumes a maximum of 300 Watts.
Managing large DU deployments without automation is not cost effective, and so we added a full range of zero touch provisioning (ZTP) capabilities. In the Rakuten Mobile Network, we use these capabilities to reduce site commissioning time from weeks to minutes and reduce operating costs by 30%.
As part of the Symware Plus deployment, Symware leverages our Symworld software platform which brings automation and cloud native operational support system (OSS) capabilities. Other automation capabilities include rolling updates, telemetry and analytics and access to cloud native orchestration and management capabilities from the Kubernetes ecosystem.
The features we’ve built into Symware will truly simplify DU deployment and deliver a massive impact network wide due to the number of units that make up the network. We’re excited to start the deployment in Rakuten Mobile to be able to show the world the results of this next-generation deployment.