A case in point is an Open RAN deployment at Germany’s largest European football stadium that pairs a multi-vendor RAN architecture with the DAS platform via O-RAN signal sources. The result is the world’s first 5G Open RAN stadium network. This converged architecture enables seamless interoperability between multi-vendor hardware and software, while simplifying DAS deployment and substantially reducing overall network TCO.

In addition, this configuration offers a significantly smaller footprint, requiring just two racks for the MNO using Open RAN signal sources, versus approximately 300 square feet per MNO for legacy base station equipment. Plus, with a nominal power budget of just 17 kW for the Open RAN DAS head-end and transmission, this architecture reduces thermal load and power consumption by approximately 70 percent.

Addressing Roadblocks

Although Open RAN offers significant potential for streamlined in-building connectivity, some challenges do remain. One of the key roadblocks is the lack of interoperability with legacy baseband vendors that are not compliant with O-RAN standards. This presents technical hurdles and complexities, adding time and money to DAS deployments. This is expected to be resolved in the near future as MNOs upgrade their network infrastructure to support the latest 5G+ and 6G technologies.

Another common issue is support for neutral-host capability of the DAS equipment to ensure that subscribers of all the major MNO networks can access service while inside the building. While this is available with current conventional DAS platforms, network evolution is occurring and is changing the way that networks are built and managed. This evolution also affects how multi-operator networks interact with in-building DAS equipment. 

As mobile network technology continues to evolve, we expect to see converged Open RAN and DAS architecture set the stage for next-generation RAN sharing models. Currently, most multi-operator DAS platforms use separate RANs for each MNO, but significant efficiency improvements are possible in the future if DAS architecture shares the distribution and intermediate layers between the DAS headend and the MNO networks.

The multi-operator RAN (MORAN) architecture presents a particularly attractive business case, with multiple MNOs sharing radios, antennas, towers, and power. In fact, a multi-operator DAS with an O-RAN (eCPRI) interface to MORAN infrastructure, either with shared or separate baseband units (BBU), offers a significantly more cost-effective in-building solution. 

To that end, the National Telecommunications and Information Administration (NTIA) awarded a grant to SOLiD to help develop MORAN signal source technology for seamless Open RAN integration with neutral-host DAS infrastructures. As MNOs move toward progressively greater architecture sharing in the future, we can expect more efficient, scalable, and cost-effective deployment and maintenance of in-building 5G networks.

Unlocking Next-Generation Innovation

The convergence of Open RAN and DAS technologies presents immense opportunities for transforming and improving in-building cellular connectivity. By addressing the historical challenges of signal source procurement and proprietary infrastructure, Open RAN integration promises greater efficiency, reduced TCO, and simplified deployment, benefiting both building owners and MNOs. 

While interoperability roadblocks still exist, the industry is already moving toward practical solutions like MORAN architecture. This ongoing evolution of network architecture is poised to unlock substantial cost and efficiency benefits, enabling a more scalable, cost-effective, and innovative marketplace for next-generation in-building networks.