Another Role for Distributed Antenna Systems – The Outdoor Opportunity

We tend to think of DAS systems as indoor solutions for enterprises and large buildings. But recent announcements from TE Connectivity reinforces the possibilities for DAS in outdoor carrier installations.

A distributed antenna system (DAS), in a nutshell, anyway, is a mechanism for boosting the signal strength of (typically) a cellular service (typically) indoors. Cellular signals usually do not penetrate buildings very well, so a DAS is one of the key techniques for improving coverage, especially in large structures. These are the big brother to cellular repeaters, a number of which I've reviewed in these pages over the years. A DAS is, of course, only one possible solution; others include micro- or picocells (smaller base stations), femtocells (these more common in residential environments), offload to Wi-Fi, and simpler and less effective booster amplifiers. DASes are typically categorized by whether they are single-or multi-carrier, sold to end users directly or provided via carriers, and implementation details like the type of cabling required to interconnect the indoor antennas.

But a DAS can also be used outdoors to augment cellular coverage without adding more expensive base stations. The core idea is to remote existing base-station capacity to locales that are relatively underserved, and to save money in the process. There are many special applications for an outdoor DAS as well, such as tunnels and hilly terrain where provisioning sufficient base stations to provide reliable coverage and capacity could get very expensive indeed.

To learn more, I recently spoke with senior executives of TE Connectivity, who acquired DAS leader (among other communications products and services) ADC back in 2010, and who recently announced significant enhancements to their DAS product family. The company offers a broad range of DAS systems - the InterReach product line, a low-power indoor solution, and, of particular interest here, the FlexWave Prism system. FlexWave Prism can cover a broad range of frequency bands, and provides modular growth. By definition a DAS should be independent of a specific air interface, and FlexWave Prism can also support multiple bands simultaneously. A robust management system, essential in my view, is also part of the package.

I'd love to see a good cost comparison between the outdoor DAS approach and using more conventional base stations. While smaller-cell base station implementations are indeed getting cheaper, I suspect that DAS will still provide a financial advantage in the majority of deployment scenarios with no compromise in overall system capacity.

Copyright © 2012 IDG Communications, Inc.

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