The Great Invisible Wireless Systems in Commercial Buildings

April 4, 2015

It has been said that the best things in life are free.  In the same way, it can be said that some of the best technology systems are invisible  (or at least have low visibility since most of the hardware parts are placed out of view whenever possible.)  Nevertheless, these systems are of a great service to people today, indispensable even.

In this article, we will discuss three (invisible) wireless systems commonly used in commercial buildings:

  1. Distributed Antennae System used for enhancing cellular coverage inside the building.
  2. First Responders System used to enhance radio communication for emergency workers.
  3. Wi-Fi Systems primarily used for wireless internet coverage.

Distributed Antennae System (DAS)

The research shows that 90% of all cell phone calls are made inside of buildings. The number of callers and the amount of data transferred through cellular networks grows dramatically year over year. That trend is expected to continue. That is one of the reasons why having robust indoor cellular coverage is important.

There are several factors which affect the coverage inside the building:

  1. Areas below the grade often have poor or no coverage.
  2. Areas above 26 floors  will have reduced coverage.
  3. Buildings utilizing e-glass, concrete inside walls (as opposed to drywalls), heavy-duty metal structures (such as in warehouses with metal racks) will experience reduced or no native coverage from macro network, especially deeper inside the building.

A typical DAS system consists of either a donor antenna on the roof or a base station on the lower levels of the building.  It also consists of a head-end bidirectional amplifier with power backup, remote communications nodes in the intermediate IT closets with power back up, a cable distribution plant and antennae located in selected locations on each level of the building, usually installed in the ceilings. It is important to note that the host neutral system accommodating several carriers in the area is preferred for higher user satisfaction.

Good cellular coverage will bring more satisfaction to the cell phone user and potentially more business to commercial establishments.  However, the cost needs to be considered and allocated within the budget.

For example, a full DAS may cost $1.5 – $2.00 per square foot, however, there are reduced-cost solutions for enhancing cellular signal on a limited basis out on the market.  In each case, the DAS is invisible to the people who will eventually use these systems.

First Responders System (FRS) 

A First Responders System is used to amplify the radio signal for emergency workers such as firefighters, police, emergency medical teams etc. It has become more popular in the last 14 years and was included in the 2009 Building Code.

More and more states and municipalities are now mandating a FRS for the buildings of certain size and height.

The FRS includes a donor antenna on the roof, repeaters, amplifiers, splitters, cabling plant and antennae throughout the building. The average cost of the system is approximately 20-30 cents per GSF.
It is important to check with code officials to gain the understanding if the system is required to make necessary provisions. It is not unusual for the outside structure to be fully constructed before knowing if the system shall be required. The test by qualified personnel needs to be conducted at a strategic juncture when most of the structure is complete, but the ceilings are not yet covered, so the cabling plant still can be deployed.

If there is a DAS deployed in the building, it is generally capable of accommodating the FRS from a technical perspective.  However, differences in requirements often makes this combination impractical.

Wi-Fi System 

Wi-Fi systems are used by most (if not all) people reading this article. Chances are the hardware that provides the wi-fi  is invisible to most of you.  People just expect to have quality Wi-Fi coverage in buildings today and shall be dissatisfied if the coverage is not there or is not adequate.

The system usually consists of the controller/head-end, data switches, Wireless Access Points (WAPs) and the cables in between. The internet connection is provided by Internet Service Provider (ISP) with the speed requirements by end-users growing by the hour and ranging from 1-6 Mbps in residential facilities to 100 Mbps-1 Gbps and up in the commercial and governmental buildings. End users are using computers and other hand-held devices with wireless adapters functioning at 2.4 GHz and 5 GHz ranges. The 5 GHz range is becoming more popular as the communication channels are staying away from competing with cordless phones, microwaves etc., which use 2.4 GHz range.

The latest wireless standard is 802.11ac, which more than doubles the speed of the predecessor, 802.11n with the speed extending into 1 Gbps range.

The cost of the system depends on several factors, including size of the building, number of users, equipment used (802.11 ac, n or legacy a, b, g), construction of the building (open spaces, concrete inside walls etc.), signal strength minimum requirements (-70 dBm, -95 dBm etc.), equipment manufacturer (Ruckus, Cisco etc.), competitiveness of the bid process etc. The average cost of the system is approximately 40-50 cents per GSF.

Can Wireless Systems be Combined?

The question often comes up if the systems described here can be combined. The answer is yes, they can be.  However, there is often no financial gain or any other benefits which are derived from combining them, so these systems are frequently implemented on the stand-alone basis.

How Important are These Systems?

The importance of the wireless systems can hardly be overstated. Let’s take the hotel as an example.

Imagine a hotel without Wi-Fi coverage, or with very poor service.
What do those people do when this is the case?  They go to another hotel, where coverage is better.  And that can result in the hotel being  “in the red” very quickly.   Even when there is an existing system in place, and the guests were very happy with it, perhaps two years ago, chances are such a system is not bringing full satisfaction to the guests today.

Then consider the business conventions and meetings at the hotel.  The presence of a DAS or another cellular enhancement system is often a deciding factor for event planners when choosing which facilities to use for conventions.  Many event planners have had a previous bad experience with poor cell coverage and are now aware of some of the issues which can negatively affect cellular coverage (mentioned above).  So in some cases, if a DAS, or other cellular enhancement system is not present, the facility may not even be in consideration for the convention. Although the event planner wants the coverage, the DAS system providing it is generally invisible.

And then there is the First Responders System.  A FRS is often mandated by local code/AHJ for many building types.  Cellular coverage is extremely important from public safety perspective, but cellular enhancement may also be mandatory to assure First Responders ability to communicate.

What is Next?

More and more wireless systems will be coming into consideration, and their use is only expected to grow in the foreseeable future.  The need for speed will continue to grow continuously as well.

It may be invisible to most people, but in commercial development today, it is clear that it is a smart decision to plan for the future with  robust wireless systems.  NTI is happy to help.

by Ilya Rapoport PMP, RCDD/NTS

About NTI

NTI was founded in 1998 and is headquartered near the square in Lawrenceville, GA.

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