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As 5G moves from early deployment to wide adoption, major U.S. telecom providers will use small cells. They will use them to expand 5G coverage. What does this mean?
Small cells use low-power, short-range base stations. They complement the macro layer by adding capacity and improving spectral efficiency. This technology extends and densifies coverage in areas where macro sites alone cannot maintain the required:
- Throughput
- Latency
- Device density
They cover small geographical areas or small-proximity indoor and outdoor spaces.
Small cells have the same characteristics as the base stations telecom companies have used for years. They support high data rates for mobile broadband and consumer apps. They also support dense networks of low-speed, low-power IoT devices.
These capabilities make them pivotal for 5G cell planning to deliver:
- Ultrahigh speeds
- One million devices per square mile
- Latencies in the millisecond range
Table of Contents
How Small Cell Transceivers Work
According to RF Page, small cells improve the leveraging of multiple-input, multiple-output (MIMO) and beamforming. They also support operations across high-capacity midband and millimeter wave (mmWave) spectrum.
These features allow operators and enterprises to deploy capacity where macro sites cannot reach. This is particularly important for indoor environments, which generate over 70% of mobile traffic.
These small cell transceivers can be mounted to the wall for indoor usage. For outdoor coverage, small towers and lamp posts are used. Backhaul connections are less complicated than before and are usually fiber, wired or microwave.
3GPP Releases (Rels) 17 and 18 enhance integrated access and backhaul (IAB) for mmWave technology. Instead of fiber or other means, ultrahigh-speed mmWave signals connect cell sites’ backhaul directly over a cellular connection.
This method requires line of sight between the transceivers. However, it saves capital and operating expenses because no new fiber is installed.
Since the early 2020s, Open Radio Access Network (Open RAN) has played a key role in shaping small cell transceivers. Open RAN provides greater flexibility in network architecture. It splits the work between radio and distribution units to improve interoperability and reduce costs. Open RAN also plays a key role in 5G network evolution. It allows small cell deployments for high-density coverage and capacity.
Small Cell Types
There are three types of small cells in the industry today:
- Femtocells
- Picocells
- Microcells
Each type is distinguished by its coverage capability and the number of users it can support.
Network cell planners and engineers sometimes consider femtocells a separate class. Their cost, purpose and installation processes differ from those of other small cells, which are more like traditional macrocells. Femtocells are for DIY users and IT technicians. They install quickly at home or in a business, like a Wi-Fi access point.
Macrocells vs. Small Cells vs. Femtocells
| MACROCELLS | SMALL CELLS | FEMTOCELLS | |
| Average Size | 50-200 feet tall | Pizza box size (18 x 18 inches) | Paperback book size (5 x 8 inches) |
| Average Coverage Range | A few miles | 100 yards (football field) | A home or small business |
| Average Cost to Install | $200,000 | Under $10,000 | $100 |
| Deployment | Between 250,000 and 275,000 in the U.S. | Five to 10 times more than macrocells once fully deployed in the U.S. | Anyone can purchase for their home or small business |
Femtocells
Femtocells are small mobile base stations that help extend coverage for residential and enterprise-level applications. These are mainly used to offload network traffic when networks become congested. Femtocells can expand coverage and enhance building penetration for indoor consumers.
Femtocell Features:
- Coverage area: 30 to 165 feet (10 to 50 meters) (indoor)
- 100 milliwatts
- Supports 8 to 16 users
- Backhaul: Home or enterprise Ethernet
- Low cost
Picocells
Picocells are small cellular base stations that cover small indoor areas, such as buildings or aircraft. They are great for small enterprises, providing extended network coverage and high data throughput. Applications include:
- Offices
- Hospitals
- Shopping complexes
- Schools and universities
Picocell Features:
- Coverage area (indoor): 330 to 820 feet (100 to 250 meters)
- 250 milliwatts
- Supports 32 to 64 users
- Backhaul: Wired, fiber
- Low cost
Microcells
The microcell is a cell in a mobile network served up by a low-power base station that covers limited areas, such as:
- Malls
- Hotels
- Unique spaces within smart cities or transportation hubs
Microcells are generally more substantial than picocells, though the distinction is not always clear. The microcell can support more users in distinct geographic areas.
Microcell Features:
- Coverage area: 1,600 feet to 1.5 miles (500 meters to 2.5 kilometers)
- 2 to 5 watts
- 200 simultaneous users
- Backhaul: Wired, fiber, microwave
- Medium costs (more expensive than femtocells and picocells)
Massive IoT vs. Mobile Broadband
5G supports two fundamentally different traffic models: massive machine-type communications (mMTC) and enhanced mobile broadband (eMBB). mMTC (also called massive IoT) includes millions of low-power, low-throughput sensors. These sensors need wide-area coverage and high connection density.
In contrast, applications that demand high capacity, low latency and fall under eMBB or URLLC categories include:
- High‑resolution video cameras
- Autonomous robots
- Industrial systems
Small cells improve both areas by adding more connections for massive IoT. They also add capacity and improve service quality for mobile broadband.
Small cells play critical but different roles for:
- Mobile broadband: Small cells are vital in providing midband and mmWave coverage, which requires line of sight coverage. Mobile network operators can use deployed small cells with the new midband spectrum licensed in the 3.5 GHz frequency range. They can overlay the new signals in the new spectrum to increase capacity and raise average data rates. This is due to wide bandwidth, like 100 MHz in C-band.
- Massive IoT: Small cells lift the areal density of 5G connections for swarms of sensors and other low-power, low-data IoT devices.
5G is necessary for new, advanced technologies that will be internet-, AI- and sensor-enabled. Companies and organizations will have to rethink or update antiquated IoT strategies.
5G Expansion and C-Band-Enabled Small Cells
5G is a significant improvement in mobile broadband capabilities. Ongoing C-band spectrum deployments are core to this rollout.
C-band closed the gap between sub-6 and mmWave. New small cells supporting the C-band are now deployed to enhance coverage and capacity.
Early 5G announcements emphasized mmWave trials and limited hotspot deployments. However, most large‑scale NSA rollouts by leading MNOs relied primarily on midband and sub‑6 GHz spectrum. This approach was favored over deploying mmWave small cells.
As C‑band spectrum became available, operators accelerated the deployment of C‑band‑enabled small cells. These small cells offer a far better balance of coverage, capacity and deployment cost than mmWave.
Private 5G Networks
With the C-band spectrum expanding for 5G, small cells will continue to be used more in private 5G networks. Demand for network slicing and stand-alone (SA) 5G networks for new use cases and enterprises will fuel the push for more dedicated small cells.
Axon Enterprise Inc. and a leading MNO showcased a public safety use case involving network slicing. They sustained performance levels for mission-critical functions while sending video data over a network slice in a commercial 5G environment.
Another notable instance of network slicing was during the Las Vegas Grand Prix. Race car driver Lando Norris live-streamed an HD video tour of his garage. He used a 5G mobile device and a network slice from a leading MNO.
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Key Takeaways
- Small cells enhance 5G by providing capacity and extending coverage in areas where macro sites are insufficient.
- There are three types of small cells: femtocells, picocells and microcells. Each has distinct coverage and capacity characteristics.
- Small cells support massive IoT and enhanced mobile broadband, improving connection density and service quality.
Editor’s note: This blog was originally published on 12 March 2020 and has since been updated.
