As the world moves toward implementing LTE Enhanced and 5G mobile wireless technologies, buildings of all types will need in-building wireless systems to provide strong coverage and capacity. While mobile operators have deployed such systems in large venues like stadiums and airports, they have de-emphasized funding for enterprises, so it is up to enterprises to deploy these systems themselves. Distributed antenna systems (DAS) are the primary means of enabling in-building wireless coverage, but traditionally, these systems have been too complex and expensive for most enterprise deployments. Recently, however, new types of DAS have emerged that are tailored to the needs of enterprises. In this article, we’ll look at the challenges enterprises face in deploying DAS solutions, and the requirements for DAS that overcome those challenges.
Enterprise DAS challenges
Traditionally, every DAS deployment has essentially been a custom effort, with the system specifically designed for each venue. A DAS consists of a head-end or main hub that connects to the RF signal source(s), intermediate hubs that distribute the signal, and remote units that broadcast the signal throughout the structure. In most cases, these DAS use coaxial cabling as the transport for the signal, and because the RF signal attenuates over long runs of coaxial cable, the system must be configured, tuned, and optimized for effective performance at each remote antenna. Also, most traditional DAS use a specific type of remote unit for each frequency to be supported, which complicates deployment and optimization in systems that support multiple frequencies, as most do.
In the enterprise, IT departments are used to standardized, plug-and-play devices that are connected with structured cabling (Cat6A Ethernet and single-mode or multimode fiber). They are reluctant to bring in specialized teams to deploy coaxial cabling, signal splitters and other specialized components, calculate the RF characteristics of a signal carried over coax, test the performance of RF at each antenna, and optimize the overall system. There are several reasons for this reluctance.
Disruption – It can take weeks or months to deploy a traditional DAS, and the installation process disrupts normal enterprise activity.
Complex– As a specialized system, a traditional DAS is beyond the knowledge of the enterprise IT department and leaves them dependent on an outside RF expert for maintenance and troubleshooting.
Cost – It can be 50 percent more expensive to deploy a coaxial-based traditional DAS than it is to deploy an IT-friendly DAS that uses existing cabling infrastructure. Coaxial cable is two to three times more expensive than Cat6A or fiber, and there’s the additional cost of hiring outside experts to deploy it.
Fortunately, solution providers have evolved their DAS offerings to address these challenges, and enterprises can now find products that meet their needs.
Overcoming the challenges
Here are the requirements for a DAS that can easily and cost-effectively be deployed by Enterprise IT departments.
Structured cabling support – To minimize costs and deployment complexity, the DAS should rely on structured cabling as a transport layer. Many IT shops deploy their own Cat6A and fiber cabling, and there could well be existing spare cabling that can be used to drive the DAS.
IT-friendly infrastructure –The central hub, extension hubs, and remote units should look and feel like other IT systems so it’s easy to co-locate IT and DAS infrastructure in the same locations, and these components should enable plug-and-play operation. Solutions like CommScope’s ION-E use a system of hubs and access points that are familiar to IT staff. In a traditional DAS, installers need to know which port to connect to in order to support each specific radio frequency, but an IT-friendly DAS should automatically detect and support any frequency, so deployment is much simpler.
Multi-band, multi-frequency support – The DAS should be a multi-band, multi-frequency solution that supports multiple frequencies in the same layer. Traditional DAS sometimes require a separate cabling and equipment layer for each frequency to be supported, but enterprises can’t afford this type of architecture. Ideally, the DAS should accept any RF source and automatically distribute it through extension hubs to the remote access points.
Easy scalability – Many enterprises initially deploy a DAS to solve a specific coverage problem in a specific part of the building, but because traditional DAS systems are customized, they are difficult to expand or modify. An enterprise-ready DAS should be easily scalable to support building sizes from 100,000 square feet to millions of square feet with a pay-as-you-grow model, and the IT staff should be able to extend the DAS by adding extension hubs and remote access points. In CommScope’s ION-E system, for example, one central access node can support up to 32 extension nodes, each extension node can support up to 16 universal access nodes, and access nodes can be daisy-chained to extend the deployment further.
Easy to commission and troubleshoot – Despite their plug-and-play nature, today’s enterprise-friendly DAS solutions still need troubleshooting capabilities. The most advanced products include scanners and spectrum analyzers to help the IT staff pinpoint RF issues.
Fiber efficiency – Enterprises often want to minimize the amount of fiber in their networks, and sometimes have no dark fiber available with which to add a DAS. A modern, enterprise-ready DAS can leverage wave division multiplexing (WDM) to minimize fiber requirements. A WDM multiplexer allows the technical staff to add multiple wavelengths to an existing fiber and use a separate wavelength to carry the DAS traffic.
Support infrastructure convergence – Enterprises want to gain maximum leverage out of their structured cabling plant, and DAS solutions can help by supporting a common infrastructure for Wi-Fi access points, security cameras, and other devices. To enable this, the most advanced DAS solutions incorporate Power over Ethernet to power their remote access points, and each access point has an RJ-45 connector that can connect to other devices so they can share the same cabling infrastructure.
Simplicity – An ideal DAS solution should have architectural simplicity. Traditional DAS products often consist of dozens of components, making them hard to deploy and difficult to stock in inventory. A simpler architecture makes it easier to inventory and order components, and the enterprise can invest in components and know that they go together like building blocks.
Enterprises will need in-building wireless coverage in order to support users for whom a cell phone is their primary means of communication. While DAS was once out of reach for many organizations, enterprise-friendly DAS products are now on the market to meet wireless challenges for any business.
