Summary Bullets:
- Small cells were originally defined as miniature, low-power mobile base stations.
- That definition is getting murkier as the product category evolves to address changing market needs.
Small cells have always been a bit hard to define. In the simplest terms, they are miniature, low-power mobile base stations. That definition was complicated somewhat by the arrival of low-power radio units that connect to the same baseband units found in standard (macrocell) base stations. These products were called small cells as well – whether deployed outdoors or in enterprises (examples of the latter include Ericsson’s Radio Dot System and Huawei’s LampSite). And the complications didn’t stop there.
Lately the definition of small cells has been getting blurrier. Ericsson, for one, has begun referring to its small-cell portfolio instead as its “urban wireless” portfolio, to reflect the inclusion of offerings like its Street Macro products, which are deployed at street level like small cells but have high power output and capacity like macrocells. This shift toward filling in the gap between small cells and macros isn’t entirely new; Nokia has been offering a “Mini Macro” product – falling in that middle ground – since 2015. And Ericsson isn’t the only one looking for alternatives to the term “small cells;” Huawei began describing its LampSite platform as a “Digital Indoor System” last year.
Part of the reason the small cell landscape is changing is vendors’ desire to expand the addressable markets of these products toward new needs and opportunities. Huawei, for example, has been especially active in this effort, pushing its LampSite into adjacent territory. After having originally targeted the underserved middle ground between large enterprises that typically favor distributed antenna systems (DAS) and smaller enterprises best served by individual small cells, Huawei has branched out in both directions: It has pursued more direct competition with DAS systems in large venues, and it has introduced new versions of LampSite for smaller venues: LampSite Spartan and LampSite Libero. Huawei’s moves aside, small cells across the industry are spilling over into multiple new use cases, with the growth of private LTE networks, Citizens Broadband Radio Service, and the Internet of Things.
Another force disrupting the boundaries between small cells and macrocells is the rise of millimeter-wave base stations and radios, an important part of 5G. Because high-frequency millimeter wave (mmWave) spectrum has a limited range, mmWave equipment is typically deployed closer to end users, in compact form factors reminiscent of small cells. At the same time, some mmWave radios feature higher power output and capacity than we normally associate with small cells. When I asked a representative of a major RAN vendor recently if their company’s latest mmWave product was a small cell or not, the answer was a frank, “I’m not sure.” Across the industry it’s likely that mmWave products will be considered a new category – distinct from macrocells and small cells both.
Over time, as the once-clear distinctions between small cells and macros become less useful, they’re likely to be eclipsed, in vendors’ marketing messages, by more important distinctions between outdoor and indoor products, between mmWave and more traditional cellular radios – and perhaps between equipment sold to operators and that sold to enterprises (CBRS and IoT gear, etc.). Still, the term “small cell” isn’t likely to disappear anytime soon, even if the changes taking place in this area are anything but small.