How an active DAS system works

The advent and widespread adoption of distributed antenna systems have brought unprecedented reliability and speed to market users, benefitting multiple end-users that ensure a holistic approach to the technology. 

From commercial applications to industrial setups, all the way to first response systems, this technology brings unparalleled networking to its users. Naturally, with such a unique product, many have been intrigued by the technology. 

Let’s explore the Distributed Antenna System and its components and the reason behind its adoption within large indoor spaces and areas where large numbers of people meet. 

A DAS is simply a network of distributed antenna-equipped radio units serving an indoor or outdoor location. Various signal sources are connected to a head-end unit that fits multi-band radio units. 

First, let’s do an overview of how active DAS technology works:

 

Signal Sources 

A DAS system is incapable of producing a standalone signal by itself. These signals are fed from sources such as a service provider feed, Node-Bs, and small cells. 

Multiple service providers can provide their respective signal feed making it a multi-carrier active distributed antenna system. 

Only major service providers can provide the feed, while Mobile Virtual Network Operators (MVNOs) would need permission from the leading service carriers.

POI Tray

The Point of Interface (POI) tray, located between the signal sources and the head-end unit, combines RF signals from various RF sources before delivering them to the head-end equipment.

These signals differ in nature, and their abrupt and direct combination at the head-end unit can result in a diversity imbalance. The same can also be achieved by using standalone hybrid combiners, which are traditional.

The POI tray offers an added value, whose configurations attenuate these downlink signals before they are delivered to the head-end unit, thereby preventing excessive power loss and heating given the difference in power output between units.

 

Head-End Unit 

The head-end equipment room houses the head-end unit parallel to the signal sources. The RF modules provide further signal filtration and amplification based on the signal frequencies. 

A series of uplink-downlink port pairs, one for each radio unit, are installed on the other end to facilitate area-wide signal distribution. It implies that the head-end equipment room hosts some if not the most critical components of an active DAS system.

One thing to keep in mind, not only should it be large enough to house the electronic components, but it should also be adequately equipped to handle their excessive heating and impart cooling after that.

 

Radio Units 

Active DAS radio units receive signals from the head-end team, segregate, amplify, and redirect to the nearby regions through antennas. This process oppositely is carried out in the uplink direction. Depending on the transmission power and the different frequencies supported, different types of radio units are deployed in accordance.

 

 Fiber Optic Cables

Light, flexible, and versatile fiber optic cables are not only perfect for active DAS but are a requirement. 

Their convenience and ease of use make them an easy choice; since the optical signal attenuation in fiber optic cables is low, it allows the free placement of radios at a considerable distance from the head-end unit without causing signal loss or loss of signal gain. 

 

Conclusion 

While seemingly complicated and full of surrounding myths, a distributed antenna system would allow its users to solve common problems or inconveniences through modern, tried, and proven technology. Such a system enables users to benefit from various benefits tailored to their specific needs.

Our industry experts can help you understand the overall process of DAS setup and how these systems are integral for structures to attract people, businesses, and institutions for everyday use. Reach out to our team to get the conversation started! 

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