Femtocells, Picocells, Small Cells or Compact Base Stations – Another round of taxonomy debates!

After our recent whitepaper on Compact base stations there have been a lot of questions on why we didn’t include femtocells within the coverage. The reason was because we see femtocells as low power access points, where the output power is typically 10mW-100mW for indoor residential grade femtocells, and 200-300mW for enterprise grade or metro femtocells. Rural femtocells (currently in development) are known to have output power between 200mW-1W. We would typically classify any femtocell between 200mW-1W as a super femtocell or greater femtocell. The self-configuring, self-provisioning characteristics of femtocells do change as we increase the output power and user capacity and become semi auto-configurable. Some would debate that greater femtocells are indeed picocells.



On the other hand we see compact base stations as a different breed of base stations, albeit cousins of femtocells. Compact base stations use femtocell silicon efficiencies and multi-core chipset platforms to build a base station on a SoC - but are meant to be higher output power base stations (1W and higher). Compact base stations are scalable platforms, which can fit into picocell, microcell or even macrocell form factors. The emergence of compact base station can be traced to the need for multifrequency, multimode, low power consumption, low-cost, pizza-box type base station platforms that can de deployed within different site classifications especially in metro metrozone overlays. The capacity crunch in networks is likely to drive operators to deploy compact base stations as in-fills initially with compact base stations being a part of future network blueprints. Current microcell or macrocell platforms are too bulky or costly to deploy in clusters and in large numbers. Compact base stations are also meant to take advantage of backhaul relay techniques making it easier to deploy in small clusters.



Small cells on the other hand could be the umbrella under which compact base stations (portion of), picocells, microcells, residential, enterprise, rural/metro femtocells exist. We are already seeing vendors like Alcatel Lucent change their marketing message from femtocells to ‘small cells’ covering a wider range of products and deployment types. They have also included features like SON and value-added applications into the small cell base category.



Chipset vendors are also positioning themselves to cater to various segments of the small cell market. picoChip, Percello, Qualcomm, DesignArt, Mindspeed, Texas Instruments, Freescale, Xilinx are all catering to the small cell market although they might be catering to different sub-segments within small cells. The vertical sub-segments include basic residential, SME, large enterprise, metro, rural environments which all have different requirements.



The marketing departments within the chipset vendors and OEMs that are linked to different sub-segments of the market will likely decide where this debate is headed. This reminds me of the debate we had a few years back on whether femtocells overlap with picocells or vice versa. It looks like there might be an added dimension to this debate with the inclusion of compact base stations and small cells.



There are still questions on what is included within small cells. Do Outdoor DAS systems count as small cells? Or are small cells only meant to include non-distributed systems?



Let the debates begin!