Macrocell vs. small cell vs. femtocell: A 5G introduction

Defining macrocell, small cell and femtocell

Macrocell

A macrocell is a cellular base station that sends and receives radio signals through large towers and antennas. Cell towers, in particular, can range anywhere from 50 to 200 feet tall and provide cellular coverage for miles. The U.S. currently has about 210,000 macrocells across the country, according to the Wireless Infrastructure Association.

Small cell

A small cell is another type of cellular base station that is physically small -- around the size of a pizza box -- and transmits radio signals. The goal of small cells is to boost wireless network connectivity in specific areas, as small cells can enable mmWave frequencies with high-speed broadband connectivity. The U.S. plans to deploy five to 10 times more small cells than macrocells, according to industry reports.

Femtocell

A femtocell is a wireless access point used to enhance indoor cellular connectivity. Unlike other cellular connectivity options, femtocells connect back through the internet to provide in-home or office cellular connectivity. Femtocells look and operate like routers, and users can place femtocells near their current network hardware setups. Femtocells are accessible to anyone who wants to purchase one.

Macrocell vs. small cell technology

While both macrocells and small cells provide 5G connectivity, their signal propagation and building penetration capabilities differ greatly. Signal propagation -- the coverage radius -- is the key difference between macrocells vs. small cells. Macrocells provide low-frequency coverage for miles, while small cells provide high-frequency coverage from 10 to 2,000 yards.

Building penetration refers to whether the connectivity works indoors. Lower frequencies from macrocells travel far, and walls, windows or other physical barriers don't block the signals. On the other hand, small cell technology has line-of-sight limitations, which means physical barriers can block the signal so it can't reach multiple rooms indoors. Yet, mmWave frequencies still make small cells promising, despite their challenges.

Another difference between macrocells vs. small cells is cost. Macrocells traditionally cost around $200,000 to set up, while small cells cost under $10,000. Even if carriers deploy 10 times the number of small cells compared to macrocells, the cost of small cells is still significantly less than full macrocell deployments. Carriers are updating existing macrocells to 5G as well, but this transition is expected to take several more years.

Small cell vs. femtocell technology

Femtocells, picocells and microcells are often considered types of small cells because of their smaller size and limited coverage, but small cells and femtocells do have variations. Picocells and microcells are commonly used in airports, hotels and malls, but the distinct definitions of these devices are inconsistent across the wireless industry -- although microcell is likely a former term for small cells. Femtocells, however, preceded small cells and make up a separate market due to some key differences.

One difference is how small cells and femtocells connect back to the network. A small cell connects on a dedicated link. A femtocell connects back on the internet. Another difference is a femtocell is private, while a small cell is a public network.

Femtocells are also smaller than small cells -- around the size of a paperback book or smaller -- and don't have the line-of-sight restrictions that small cells have. If a user places a femtocell in a central location in a home or office, that person should get sufficient coverage. Also, as femtocells are private, only one person's devices can connect to the femtocell, whereas anyone can connect to small cells.

Femtocells are similar to routers in appearance, function and cost. Femtocells cost around $100 and can improve indoor coverage for locations too small to justify the investment for a full digital antenna system.

Small cell and femtocell use cases differ as well. For example, femtocells are to Wi-Fi routers as small cells are to Wi-Fi hotspots, meaning small cells can boost cellular coverage in areas where people congregate, such as stadiums, like a Wi-Fi hotspot for internet connectivity.

Expectations for small cell technology

While key differences among macrocells vs. small cells vs. femtocells are evident, 5G small cell deployment is ongoing as carriers use the technology to fill in coverage gaps.

When carriers deploy mmWave, consumers and enterprises may experience some quirky problems, as this slice of spectrum is new to both markets. With the line-of-sight restrictions and inability to travel long distances, mmWave is a major adjustment for carriers and users alike.

Backhaul is also a major issue regarding small cell technology, and carriers need to develop an effective answer to this problem. This issue is especially pertinent if carriers place small cells on objects such as lampposts, which are supported by electric power rather than the fiber links small cells require.

While small cells appear to be helpful hotspots for places such as stadiums or outdoor event centers, carriers may need to plan for wide-area small cell deployments. Despite the shortcomings and unknowns, small cells remain critical facets in 5G plans. Essentially, small cells are a growing and important part of how carriers intend to deploy 5G. Although small cells have technical limitations, they can help heat up a hotspot.

Editor's note: This article was updated to reflect changes in small cell 5G deployments.