What, exactly, is a small cell? Does “small” mean that the hardware fits in a suitcase? Does it mean that the radio channel has a limited range? Can a small cell only handle a handful of users? As operators look for solutions to their coverage and capacity challenges, these questions come up a lot.

Fortunately, the Small Cell Forum (www.smallcellforum.org) has the answers. The SCF is an international industry group comprised of small cell technology providers and mobile operators involved in developing and deploying small cell solutions. Although the SCF is not a standards body, it works with standards organizations and regulatory agencies around the world to define common approaches for small cell solutions.

Small Cell Definitions

So what is a small cell to the SCF? Their website defines small cells as follows:

“Small cells are low-power wireless access points that operate in licensed spectrum, are operator-managed and feature edge-based intelligence.”


The key points here are:

  • Low power: Small cells operate at significantly lower power levels than normal base stations. Where a typical cellular base station might broadcast with 40 Watts of power, a small cell may transmit at only 50 milliWatts, depending on the particular environment.
  • Licensed spectrum: Small cells use the same spectrum and radio technologies as the mobile wireless network they’re associated with, allowing a more seamless integration with the macro network and a more consistent user experience.
  • Operator managed: Although a small cell may be physically deployed by the end user, it is still considered to be part of the operator’s network, so that it can be configured and managed along with the other cells in the network.

This definition leaves out things like WiFi access points, which use unlicensed spectrum and are usually managed by the individuals or businesses that bought then.

 

By most measures, small cells are indeed small. The units themselves are typically less than 6 cubic feet in volume (and many are no bigger than a WiFi router) and consume very little power. Their lower output power restricts their coverage area, while their less powerful processors limit the number of users they can handle at one time.

Even so, there is a spectrum of solutions that fall under this rather broad “small cell” definition. The SCF further subdivides small cells into three types:

  • Femtocells (also called residential femtocells) are the smallest of small cells, providing coverage for a single-family home with 4 to 6 active users.
  • Picocells (sometimes called enterprise femtocells) are intended to serve multi-story buildings and campuses, which each picocell handling up to 32 users.
  • Microcells are generally used in outdoor environments to provide additional coverage and/or capacity to the network, each carrying up to 128 users. Urban microcells (as opposed to rural microcells) are often referred to as metrocells.

Small Cell Benefits

So what can a small cell do that a macro cell can’t do? The short answer is: nothing. Small cells can do everything that big cells can do, except cover a lot of territory and serve a lot of users. The value of a small cell is not its horsepower, but its economy. If the operator needs to add additional capacity in a particular location, or fill in a coverage hole, a small cell can often do the job for a fraction of the cost.

This cost advantage comes from a number of factors:

  • Lower equipment costs: Because they are physically smaller and much more integrated than macrocells, a small cell may cost hundreds of dollars rather than tens of thousands.
  • Lower real estate costs: Small cells are often hung on the walls or bolted to lamp posts, eliminating the need to acquire floor space or build enclosures. Even the larger microcells have a smaller footprint than traditional macrocells.
  • Plug and play: Small cells are designed to simplify the deployment effort, allowing the cell to be connected to the network and configured with little or no manual intervention. Coordination with the rest of the network is handled by the operator’s automated management systems, further reducing ongoing operational costs.

The end result is a suite of economical solutions that the operator can deploy to handle a wide variety of opportunities, including (but not limited to):

  • Improving in-home coverage and performance (residential femtocells)
  • Covering campus and corporate environments (enterprise femtocells and picocells)
  • Filling in coverage holes, offloading macrocells and adding additional “hot spot” capacity (urban microcells and metrocells)
  • Serving remote areas that would otherwise not have service (rural microcells)

Small and Cheap for the Win

Market studies indicate that small cells (especially those intended for LTE markets) are poised for significant growth in the coming years, with some sources estimating a 50% growth in deployed units in the next year. With more and more people using wireless as their primary means of communications and Internet access, operators are searching for solutions that will allow them to grow their networks and expand their capacity, without growing their costs commensurately. Small cells offer the right combination of power and price to address those needs.


If you’re interested in learning more about small cells, check out the “Emerging Trends” section at http://www.awardsolutions.com for information about our small cells curriculum, or the “Training Events” section for upcoming public course offerings.