Unlocking Better Coverage: The Essentials of Cellular Enhancement 

What does it mean to have good cell coverage?

In today’s connected world, seamless cellular connectivity has become a universal necessity. People expect and rely on connectivity everywhere — whether they are indoors or outdoors, in a small midwestern town or a densely packed borough of the Big Apple. 

While the need for proper cell connectivity has continued to grow (and the demand for data has increased exponentially), cell networks have become increasingly over-taxed, harder to deploy, and altogether less reliable. As 5G becomes a reality throughout the country, network engineers are scrambling to keep 4G LTE networks and new 5G networks simultaneously operational, with proper coverage and capacity available. 

Having good cell reception available in your commercial building isn’t as simple as it sounds. There is a confluence of variables required to have adequate coverage in an area. The three main factors are:

• Signal Power- Generally, signal power can be understood as the “volume” emitting from local cell towers. The higher the power, the louder the volume, and the easier your phone can hear/connect to the available signal. Signal power is typically measured as RSRP and measured in decibels. 
• Signal Quality- Signal quality is a measurement of how clean the available signal is. It can be thought of as the clarity of signal vs. the other network noise in an area. In any area in the country, there will be some type of noise on the cellular network from other devices broadcasting in similar spectrums. This creates a noise floor that the cell signal must overcome for phones to connect. Signal quality can be measured as RSRQ or SINR. It is a vital piece of how your device operates. 
• Signal Capacity– The third critical piece that determines cell connectivity is the available signal capacity on local cell towers. Imagine for a moment that a cell tower is capable of supporting 100 voice calls. If 101 people are on calls at the same time and trying to access the same tower, the tower will not have enough capacity for all the users, and someone will be unable to make their call. We see this often in high traffic events and venues. It can also be seen in dense downtown environments where the pace of population growth outpaces the cell infrastructure. 

What Impacts Coverage?

There are a number of reasons that cell reception might be less than perfect, but they all trace back to an effect on one of these three variables. Some of the reasons that coverage might be poor in a location include:

• Distance from cell tower

• Building materials blocking coverage (inside a house/commercial building)

• Too many people on the network

We will focus specifically on how coverage can be impacted within buildings, as improving coverage in outdoor areas is equally important, but is a role typically reserved for the carriers. 

What Factors Block Cell Signal Inside Buildings?  

While there are many potential factors that can influence if coverage is going to be available inside a building, there is no guaranteed formula to determine if signal will be a problem. Determining if coverage is an issue inside a building needs to be determined on-site using test equipment and site survey methodology [link to Testing page]. This CAN be done before the building is built, but the results get more accurate the more complete the building is. 

There are a number of factors that impact coverage within a building, but it’s generally more important to look for some of the key impacts. The more key impacts a building has, the higher the likelihood that it will have cell reception issues.

• Building Materials Like Steel and Concrete. Any building that is built with heavier grade materials like steel and concrete will immediately create more signal loss due to the less penetrable nature of the construction materials. 

• Low-E Glass. Energy efficient glass is the primary blocker of coverage outside of steel + concrete building materials. Its mechanical composition makes it act like a mirror for RF signals entering the building.
• Large Floor Plates. The larger the floor plate, the more of the indoor area the signal needs to penetrate. For a very small floor plate, the signal may only need to penetrate 50 feet past interior walls into the center corridors. For a massive floorplate, signal may need to penetrate hundreds of feet into a building.
• Other Large Scale Buildings in the Area. Similar to how building materials block coverage, a building between yours and the cell tower will create enormous impacts to the cell network.
• Highrises. Generally speaking, we will see signal start to degrade around the 15^th floor of most buildings. Simply put, cell towers are meant to provide coverage to the densest subsection of users possible, which is typically street level and up to around 150’ in a typical city. Above this, we start getting less signal coming in from exterior cell towers.
• High Volume of People. Adding thousands of users to a network is nearly guaranteed to stress the network and add congestion. Whether or not it goes over the critical threshold of the cell towers generally has to be observed over time
• Underground environments. Subterranean areas such as basements and parking garages will have problems with cell coverage in nearly all instances, effecting not only cell phone users but also car charging stations and other IoT devices underground. . 

These are the primary risk factors to keep in mind when building a project. However, it’s best to get the on-site work completed to measure coverage levels during and after construction as the risk factors can be good indicators you will have poor/average/good signal, but only a survey can determine fully (and catch it ahead of time).

Solutions for Better Coverage

A wide range of solutions can be deployed to solve coverage issues within large scale indoor environments. The capabilities and types of technology have grown exponentially since it became a burden of the building owner to solve coverage gaps. 

Early in the history of cell coverage solutions, carriers funded many of the systems that you might connect to in a building. However, as the model evolved, the responsibility to solve coverage in a building passed to the building owner.  This necessitated some changes to the technology, as solutions were needed at different price points to accommodate various budgets and building types. The following list is a general review on some of the main approaches but is by no means an exhaustive list.

Cell coverage continues to evolve, and more importantly, the solutions continue to become more hybridized. Meaning, the lines between different solution types are less clearcut, as the solutions all borrow the best features of each other to create more “in between” approaches. 

Cellular DAS Solution Categories

SOLUTION TYPE	APPLICATION	BRIEF
Residential Grade Booster	Small scale applications such as a 2-3 room office or a single residential home	These solutions are quick to install and cover around 2-3k sq/ft. They use the outdoor coverage to provide better signal.
Commercial Grade Cellular Repeater	Lower density users in larger square footage. Good fit when voice is a priority, but data speed isn’tThese solutions use the rooftop signal to bring coverage into the building. They are somewhat limited to only providing the quality of signal that can be found outside.	These solutions use the rooftop signal to bring coverage into the building. They are somewhat limited to only providing the quality of signal that can be found outside.
Hybrid Cell DAS	Highly modular and can be deployed in almost any instance outside of massive user density (convention centers, transit depots, stadiums).	These systems can use an antenna on the roof or bring in carrier direct hardware. They have more intelligence than a typical cellular repeater and can scale infinitely to meet the square footage needs.
Active Cellular Das	Deployed in the largest scale environments. Can accommodate anything from large scale class A office to airports.	These systems will typically bring fiber sources direct from carriers to distribute the signal. Infinitely scalable and capable of handling nearly any number of users when properly designed.
Standalone Small Cell	Solutions where a single carrier or 2 carriers is acceptable.	These systems span a large range of technologies, but they typically distribute a single carrier throughout a building by way of small cell interface. Note: small cells can also be injected into active cellular DAS to serve as the signal source input.
Private LTE/CBRS Solutions	Areas where there is a use case for a private network or cellular is a challenge to deploy.	These solutions are more cell DAS adjacent rather than being strictly cell DAS. They include a large range of technologies geared around finding new ways to bring wireless indoors for less cost.

Future Trends

Our predictions about the future of cell enhancement are typically based on what we want to see in the industry. Due to Illuminati Labs’ performance record and reputation in the industry, manufacturers often seek out our expert advice regarding new developments and we are happy to share.  Even so, change can be slow as all solutions need to be properly vetted and tested by both carriers and regulating agencies such as the FCC.  

The following future trends are heavily based on the largest pain points facing the industry, realities of building owner budgets, and direction from the carriers. 

• Easier Signal Source: Signal source has long been the Achilles heel of cellular DAS. To bring in carrier hardware — whether base stations or small cells — there is a cumbersome, expensive process with unknown timelines and unknown costs. This causes many building owners to hold off entirely because the solutions can be seen as risky to deploy. We are beginning to see carriers and manufacturers work together to bring easier signal source to the marketplace. 
• More Competition, Better Solutions: As more teams enter the marketplace and push each other to provide better solutions, the technology will evolve, and cost pressures will push pricing down.
• Specialization Remains: Efforts have been made over the years to create cell enhancement solutions that can be deployed by a low voltage integrator. These solutions have improved, but the nature of RF is radically different than any other technology within the building. A specialized team to design/install/commission the system will remain well worth the premium. 

In Conclusion

As 5G continues to mature and emerge, and the need for lightning-fast data grows, the expectations on cell connectivity will exist everywhere. It is no longer enough to hope that a building will have adequate coverage. Coverage must be assessed and audited early in the process, and great care should be taken to evaluate the proper way to solve cell connectivity when it is an issue. 

New ways are constantly emerging to bring better cell coverage into buildings, and it is in every building owner’s best interest to understand the current state of their building reception, the options to solve coverage gaps, and the best way to future proof their buildings.