All you need to know about small cells

Small cells are radio access nodes – which provide the wireless connectivity between user devices and the mobile network’s core infrastructure – used to improve network coverage and capacity, especially in areas with high demand or poor cellular signals. In other words, small cells help to increase coverage and connect cell phones (and other similar devices) to the network.

Though less powerful than macro towers, small cells increase the overall network capacity by offloading traffic from the macro network into a localized access point. Additionally, small cells are vital for 5G networks because they enable higher frequencies, denser deployments, and specific 5G use cases such as enhanced mobile broadband. Small cells are necessary to deliver the high data rates and low latency that make 5G networks desirable.

There are three types of small cells. The first, femtocells, have a range of a few hundred meters and are designed for small businesses and residences. The second, picocells, have a medium range and can be used in individual buildings, like offices. Finally, microcells can cover a few kilometers and are functional in outdoor urban areas.

In addition to enhancements in network coverage, capacity, and 5G capabilities as mentioned above, small cells bring the network closer to devices. This leads to higher data rates, lower latency, and an improved overall user experience. The use of fiber optic cables to connect small cells also means that they can handle large amounts of data at high speeds compared to traditional backhaul. Small cells can be more cost-effective for telecommunications operators than deploying macro cells, particularly in scenarios with targeted capacity and coverage needs. They are also compact and can be discreetly installed in existing infrastructure like utility poles without sacrificing aesthetics.

Small cells connect to a mobile operator’s core network through backhaul links such as fiber optic cables or microwave links and use the same radio access technologies as macro cells, although at a lower power level. They use technologies like beamforming (which optimizes signal directivity), higher frequency bands, and advanced antenna systems to improve spectral efficiency, thus providing greater signal quality in their designated coverage area. Usually, small cells are deployed in dense, multi-layer architecture, filling in gaps in coverage and/or capacity from the macro cells. Mobile devices connect to the nearest small cell within range to improve data speed and reduce latency. The small cells then automatically coordinate handovers as users move across different cell coverage areas.

Small cells are typically deployed in indoor environments (such as offices and malls), urban areas (such as city centers), targeted locations with high demand like stadiums and transportation hubs, and also in outdoor rural areas where macro coverage is limited. Usually, they are deployed as a dense added support to the macro cell layer, placed in strategic locations to provide or improve localized coverage. When choosing deployment locations, there are four important considerations:

1. Backhaul: The small cell needs to be placed in an area where it can use a backhaul link to connect to the core network.
2. Site Acquisition: Operators must secure the right to install a small cell to existing infrastructure like utility poles.
3. Power Requirements: Small cells need power sources, either through the backhaul connection or locally.
4. Interoperability: Small cells need open standards and multi-vendor support to integrate them into existing networks.

In sum, small cells are strategically deployed in large numbers at locations with high traffic and/or poor coverage, leveraging existing infrastructure as a key part of a multi-layer network architecture to improve network connectivity.

Small cells use a process called backhaul to connect with macro cell towers. The backhaul connection carries data traffic between the small cell and the mobile operator’s core network. The most common backhaul technologies used to connect small cells are fiber optic cables (which provide high bandwidth and low latency), microwave links (which are line-of-sight wireless backhaul that uses microwave frequencies) and millimeter wave links (which are high bandwidth wireless backhaul using the millimeter wave frequencies necessary for 5G). Once connected via backhaul, the small cell network can be centrally managed and coordinated with the macro network by the operator, ensuring efficient resource allocation, interference management, and load balancing between cell layers.

Small cells emit radio frequency (RF) emissions, but are strictly regulated by safety guidelines and exposure limits. The small cell devices are regularly reviewed and monitored for compliance. It is important to note that RF emissions from wireless communications have been studied for over 60 years, with international health authorities finding no conclusive scientific evidence that these signals pose harmful health effects when operating within the safety limits.

Security measures implemented to protect user data include physical security (such as tamper-evident designs that prevent unauthorized access), network security (such as encryption within IPsec tunnels, secure radio interfaces, and authentication measures), and protection against denial-of-service (DoS) attacks through traffic restriction, security gateways, and hardening techniques like firewalls. Though there is a baseline level of security measures outlined by the 3rd Generation Partnership Project (3GPP), which develops protocols for mobile telecommunications, best practices are continually evolving.

The rollout of 5G networks is one of the biggest drivers of small cell adoption, as small cells are crucial to provide a dense coverage and high bandwidth . A growing demand for outdoor coverage and the development of new small cells have also increased small cell deployment in recent years.

On the operational side, there has been an increasing focus in improving small cell efficiency through centralized management and automation, in addition to collaboration within the industry to accelerate small cell rollouts and develop best practices.

Small cells are low-power cellular radio access nodes that offer effective localized solutions to increase network capacity and coverage. Key benefits of small cells include improved coverage, capacity, user experience, and cost-effectiveness, in addition to enabling the higher frequencies and denser deployments required for 5G networks. The adoption of 5G networks is a major driver of small cell growth.