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Commercial Building Distributed Antenna System (DAS) Overview

Aug 28, 2019

Commercial Building Distributed Antenna System (DAS) Overview

What is a Commercial Building Distributed Antenna System (DAS)?

Did you know that over 80 percent of cellular phone calls start or end inside a building, not outside? A DAS consists of a network of small antennas installed throughout a building to deal with isolated spots of poor Wi-Fi or cellular coverage across buildings. Public safety DAS ensures communication devices operating on public safety bands (such as first responder radios) function properly at times of emergencies.

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Do You Really Need to Install a DAS in Your Building?

If wifi or mobile reception is weak in any parts of the building, then it may make sense to have DAS installed. Furthermore, it may be required to obtain building occupancy permit per local Authority Having Jurisdiction (AHJ).

Remember how it was back in the 1990s, when mobile phones were large and clunky and not as ubiquitous as they are today? Well, things have changed since then - a lot!

It is much easier to imagine a young person living without plumbing or electricity than without their smartphone. Indeed, the worst thing you could do to someone in this day and age is to take away their Wi-Fi and cellular signal. Do that and there would be riots everywhere, literally.

Seriously, a good Wi-Fi and cellular reception is absolutely essential to how we live and work. Any disruption in that can affect life as we know it, in more ways than one.

There's nothing more irritating than when you're making a call to someone and their voice starts breaking down because of the poor cell phone reception at your place, or theirs.

Wifi is no different. Don’t you hate it when you can't send an email from your phone because of the poor quality of the Wi-Fi? Can you imagine a day at work without Wi-Fi?

Most homes and businesses in United States still get their internet Wi-Fi from a landline based service. There're a couple of serious limitations with landline internet:

  1. Privacy concerns: Lack of security, little or no protection from potential hacking, especially in public places.
  2. Slow upload and download speeds: This is especially true in hotels, airports and large buildings where there're hundreds or even thousands of users, all on the same network.

And then there's the problem of weak cell phone reception.

What Causes Poor Cell Phone Reception?

  1. The distance between your building and the cell tower is too high.
  2. There're too many obstructions between the cell tower and your building which block the signals such as trees, valleys, mountains, tall structures and harsh weather conditions.
  3. Construction materials that get in the way, block, absorb or modify the radio frequencies.
  4. Impediments within the building such as wood, walls, drywall, plaster, electric appliances, etc.

Here's where a DAS can be useful.

DAS allows building owners to add value to their tenants, customers or employees by enabling them to use their cell phones or other mobile devices throughout the building without disruptions of any sort.

It improves coverage and the reliability of the data transfer rates, supports multiple carriers and enhances the battery life of cell phones. It ensures full signal strength to everyone regardless of their position within the building.

How Does a DAS work?

A DAS system consists of three major components.

  1. Signal source: The signal source refers to the reception that comes directly from the cell tower belonging to a carrier network. This is caught by strategically positioned external antennas or carrier signal feed in case of Active DAS.
  2. Central processing point: Refers to the repeater or amplifier at the core of the system that enhances or boosts the signals received from outside.
  3. Distribution unit: Refers to the system of antennas that distribute cellular signals and other radio frequencies and improve the reliability of the cell phone reception and Wi-Fi.

Outdoor DAS (oDAS) & Indoor DAS (iDAS) vs Active DAS (aDAS) & Passive DAS (pDAS).

Indoor DAS installations (iDAS) are more popular than outdoor ones (oDAS). As the name indicates, indoor DAS boosts reception inside buildings and structures whereas outdoor DAS boosts reception coverage in open spaces outside buildings or anywhere else. Indoor DAS requires less time and expense than the more equipment & labor intensive outdoor DAS.

There are two types of indoor DAS installations: Active DAS and Passive DAS. Both Active and Passive DAS systems are deployed by businesses across United States for enhancing cell phone reception and increasing productivity at the workplace. Passive DAS are more popular because they cost less and they are sufficient for majority of buildings.

But what is the difference between them?

Active DAS vs. Passive DAS

Introducing Active DAS:

Active DAS works best for large buildings with a built-in area of 500,000 sq. feet or more. It can help improve the 3G and 4G LTE reception and provides a much stronger signal strength to almost 95 to 99 percent of the area under coverage.

Active DAS is ideally suited to large buildings that get a lot of traffic, such as a football stadium or an international airport. There's no other technology in this category that can compete with Active DAS at this. Indeed, an Active DAS can give you limitless coverage.

Active DAS converts analog radio frequency signals from carrier networks into a digital signal. The original strength of the reception is maintained across the building regardless of its size or cable run. In a lot of ways, having an Active DAS is the same as having your own private cell tower within your building (a mini cell tower). That is how powerful it is.

Two Things to Know About Active DAS:

  1. Active DAS is expensive: It can cost you $5 to $10 per sq. ft. of coverage. This means, if you have a building of size 100,000 sq. feet, installing an active DAS will cost you anything from $500,000 to $1 million. This includes the cost of the specialized equipment, installation and the cabling (fiber optic cables).
  2. The deployment takes a while: The deployment of this system does take some time because it involves a lot of paperwork, waiting for approvals from the concerned carrier(s) and city/ government departments plus budgeting and delays. Indeed, the deployment can take many months.

Introducing Passive DAS.

A single Passive DAS amplifier unit can help improve 3G & 4G LTE cellular for up to 100,000 sq. ft. The area under coverage can be further expanded to 500,000 sq. ft by adding more units. This system is recommended for apartment buildings, retail stores, offices and other commercial establishments that have an area of coverage of between 10,000 sq. feet and 500,000 sq. feet.

What is Good About Passive DAS?

  1. Costs less than Active DAS - The biggest advantage of Passive DAS is that it is not as expensive as Active DAS. Passive DAS costs roughly between $0.50 and $1 per sq. ft. of coverage. Therefore, enhancing the coverage for a 100,000 sq. ft. building will cost anything from $50,000 to $100,000. This includes the cost of the specialized equipment, installation charges and cabling.
  2. The deployment time is much less than Active DAS - Another major advantage of Passive DAS is that the deployment time is much lower than what you get with Active DAS - weeks, rather than months. That is because these systems are much easier to install, smaller in scope and less disruptive to the existing networks.

Are there any Drawbacks to Passive DAS?

Yes, a couple that you should know about:

  1. Works well only when you have a relatively strong outside signal: Passive DAS depends heavily on receiving a decent outside signal from the nearby cell tower. You shouldn't find it hard to get cellular reception of a reasonable strength in an urban setting - but this is not so easy in certain rural or semi-urban areas. If your building is located in the countryside or in an area where the nearest cell tower is a fair distance away with building blocking the line of sight, then you should go for the more powerful Active DAS and not Passive DAS. Note A: Strong signals are usually close to -50 dB and weak signals are in the neighborhood of -120 dB. Note B: Different carriers and phones have their own metrics for determining the strength of a signal. For Verizon, a strong cell reception will have full bars, only 2 bars on T-Mobile and 3 bars on Sprint – although the signals are of the same strength and quality. Therefore, signals should be ideally measured in "decibels" using a signal meter or dB signal strenth mode within smartphones.
  2. Not so easy to get comprehensive building coverage: Passive DAS provides spot coverage for the main areas of the building only, and may not be able to cover every inch of the building. Therefore, there might still be a few small spots or locations within the building where the reception continues to remain poor despite the installation of this system.

Contact a Commercial Distributed Antenna System (DAS) Expert.

If you're considering installing a DAS for your building, contact us. We're your DAS installation experts. A DAS installation should only be completed by highly qualified and experienced technicians who are capable of designing a customized solution for your building based on your specific requirements.

Our installation team consists of telecom industry veterans who have worked closely with every major network such as AT&T, T-Mobile, Verizon and Sprint. We design the right kind of scalable systems that are customized according to your requirements.

During installation process, we carry out the following tasks:

  • Assessment of the Facility: Includes Pre-survey and Site survey.
  • System Design: Includes Data analysis, Floor plans, Discussing the Pricing and Selecting the Equipment.
  • DAS BOM: Presentation of list of required Distributed Antenna System (DAS) parts and bill of materials (BOM) with installation cost.
  • Installation: Includes actual installation of the system and its optimization.
  • Support: Includes Documentation, Monitoring and Lifetime Support.

Why Us?

  1. We have GSA Approved Certification. GSA Approval is a status used to describe organizations that have been approved to sell to the United States Government through the U.S. General Services Administration (GSA).
  2. Our installers are certified as well as experienced to finish the project as fast and as easily as possible to deliver optimal value for your investment.
  3. We're fully capable of working with LEED-certified buildings.
  4. We offer flexible funding options to our clients. Contact us to know more about this.
  5. We're iBwave Design certified and are the preferred third-party integrators of indoor connectivity solutions such as DAS for Verizon, T-Mobile, and AT&T.
  6. We offer an end-to-end service and post installation support.

Contact us today for a FREE consultation with one of our DAS experts.

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Or submit request for quote to get started immediately.

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  • I’ve heard that distributed antenna systems are helpful for buildings but I’ve also heard they are expensive. It’s a good investment when you have a lot of cell phone traffic whether it’s employees, customers, or a mix of them. Considering the cost, you might want to see how you could swing things with writing it off on your taxes.

    Walter Peckham on
  • Can the carriers pay for the DAS costs by letting them use your DAS as a tower?

    Ken on
  • Commercial buildings have some of the worst cell phone coverage. I’ve been to law offices, department stores, and other commercial properties where you either can’t get a signal or it keeps fading in and out. Distributed antenna system companies can help set these buildings up for reliable cell phone coverage, but only if businesses are willing to let them design a system and lay out the DAS architecture. I know there are different packages (active vs. passive DAS) so it’s not like businesses don’t have options to pick from.

    Jeff Carlson on
  • I didn’t know commercial buildings have so many problems receiving cell phone signals. This blog explained why this happens and how building owners have options ranging from passive distributed antenna systems to active distributed antenna systems. It all comes down to the das system cost that fits your budget. I just hope distributed antenna system companies are upfront about the costs.

    Tito Morales on
  • A building das seems like a good thing for a building owner and anyone who uses the building. The idea of a reliable cell phone signal seems obvious, but I think everyone has been at large facilities such as malls or football stadiums where getting any bars on your cell phone is difficult to do. I think it’s dangerous not being able to make calls in places like this and can only hope digital das becomes common.

    Doug Janke on
  • Whoever wrote this definitely knows how vital cell phones and other mobile devices are to people (especially young people). I think it’s ridiculous that it’s hard to get signals in big buildings like shopping malls. How am I supposed to do a price check if I can’t get access to online stores? Your explanation of distributed antenna system design helped me understand how to improve cell phone reception in big buildings. Is there any reason more buildings don’t have these? I’d think distributed antenna system companies would let businesses know the advantages of having reliable cell phone coverage. Some places are just too frugal.

    Martin White on

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