Crossing the divide between public and private cellular network technologies occurs when there is a need to extend the feature-rich public services offered by mobile network operators deep into the enterprise network. Distributed Antenna Systems (DAS) are one such well-established solution that is used to deliver public cellular signals to hard-to-reach locations like office buildings, underground facilities, stadiums and arenas, parking structures, and transit tunnels. The typical use case for deploying DAS is to offer consumers access to multiple Mobile Network Operator (MNO) services, generally not to enhance enterprise capabilities or operations.
However, if DAS is viewed through an enterprise lens, there is a real opportunity to utilize the deployed infrastructure and coverage capabilities of the DAS together with enterprise-grade private cellular networking to extend business operations, enhance productivity, support automation, and enhance communications across the enterprise.
DAS physical layer transport infrastructure
DAS is a simple physical layer technology that does not interfere with, interpret, or act upon the RF traffic it carries. DAS implementations vary greatly across manufacturers with options for signal transport over coax, fiber, or twisted pair, but all share the same common purpose: to accurately replicate and redistribute RF signals to areas that require coverage.
One illustrative application of DAS comes into play in the use of cellular phones while on a metropolitan subway. Public cellular services are unable to penetrate these tunnels directly from standard cell towers. DAS solutions are employed to transport and radiate RF signals throughout the train stations and tunnel landscape, providing high-quality macro cellular network coverage for thousands of subway travelers underground.
DAS can also be applied to private cellular networks which use the same RF technology, bands, and device ecosystem to deliver secure private wireless service alongside the public network. Simultaneously supporting travelers and private network facilities use cases on the same infrastructure can potentially remove or dramatically decrease cost barriers associated with a greenfield private network deployment.
DAS in the enterprise
The metropolitan subway example is also relevant to other common DAS applications such as sporting venues, airports, and public campuses, where the motivation to install a DAS is in direct response to the visitor expectations of being able to use their mobile devices anywhere in these facilities, on their network of choice. These DAS implementations are a ‘public network first’ motivation for wireless coverage.
Alongside the public network service, the very same DAS infrastructure can also be utilized by a private cellular network to securely manage business-critical operational technologies such as ticketing, security and access control, surveillance, operational communications, and even HVAC or smart building systems such as people counters, maintenance sensors in bathrooms, and intelligent management processes for concessions and retail shops. The secure private cellular network essentially rides for free on the DAS, and for many applications, could also provide new monetization opportunities, such as offering high-availability internet services, instant replay or streaming services, or concierge shopping services to elite customers through the private cellular enterprise network.
A further advantage of private networks and DAS is the decoupling of public visitor network demand from the operational needs and security of the private network. A private network that is fully separated and only shared with the public network infrastructure at the physical layer is immune to visitor traffic and operator outages, and is not subject to core network complications observed with other private-public service offerings, such as Multi-Operator Core Network (MOCN) integrations.
There are also examples that are not in public spaces, where an ‘enterprise first’ DAS installation is desirable, such as in warehousing, manufacturing, chemical processing, or mining. In these examples, the demand for a new wireless network is driven first by business needs, but there is also a need for employee and guest personal communications via the public network. This combination can economically deliver public network communications for visitors and employees, as well as secure coverage, mobility, and continuity for a host of workflow and operational connectivity requirements of the private network.
Enabling public cellular access throughout the private enterprise has the added benefit of engendering employee goodwill by ensuring that personal phones operate as expected for private communications. In addition, the DAS-distributed public service could provide a second tier of communications for public safety, security, and network resilience which reaches beyond the intended purpose of the private network.
Synergies economically deliver upsides
DAS is a simple unifying technology that delivers benefits in both public and private cellular deployments. DAS can be used to extend wireless connectivity and coverage on a secure private cellular network, as well as offering public network access that can enhance worker productivity and business processes. It is not often that a single platform can simultaneously serve two separate purposes, however DAS fits the bill simply and economically.
