There are many drivers for the evolution of small cells, including the densification of 5G deployments. Small cells are becoming more multifaceted, integrating more frequency bands, bandwidth, higher linearity and efficiency, helping MNOs meet pressing ROI needs. Qorvo supports small cell supply chain designers and operators in this evolution by offering a broad portfolio of PAs, LNAs, filters, diplexers, switches and front-end modules.
Today’s wireless infrastructure includes many elements—macro base stations, metropolitan area networks, outdoor and indoor distributed antenna systems (or DAS), small cells, and more—all working together in a heterogeneous network, or HetNet (see figure below).
Mobile device users are moving from smaller data packet information (pictures, emails, web browsing, etc.) to media that requires larger data packets (such as video, gaming, and live streaming). This requires networks with fast handoffs and data uplink/downlink (UL/DL) from tower to tower (no matter how big or small). Small cell densification offers an efficient and inexpensive solution and is the foundation on which the 5G future is built.
What is a small cell?
A small cell is basically a miniature base station that splits the cell site into many small pieces and is a term that encompasses picocells, microcells, femtocells and can include indoor/outdoor systems. With a macro base station, there is only one pipe into the network; if the cell is smaller, it splits the pipe into many pipes. The main goal of small cells is to increase edge data capacity, speed, and overall network efficiency at the macro cell.
Small cells were added in Release 9 of the 3GPP LTE specification in 2008 as one of the elements of network densification, or adding more base station connections to existing wireless infrastructure.
Small cells are often used in densely populated urban areas such as shopping malls, sports stadiums, airports and train stations - basically, anywhere there are a lot of people using data at a given point in time. Today, most small cell infrastructure deployments are geared toward outdoor use. In contrast, indoor small cell systems may or may not incorporate Wi-Fi or unlicensed LTE bands (LTE-U)/licensed assisted access (LAA), depending on the features the service provider wants to support.
See the figure below for a snapshot of output power, cell radius size and other features for different base station types, from small cells to macro cells.
How do small cells fit into the 5G revolution?
In layman's terms, 5G will offer greater data capacity, lower latency, and improved battery life.
5G will not replace 4G; it will simply enable a greater diversity of applications that 4G cannot perform. 4G networks such as small cells will continue to develop in parallel with 5G. (See the figure below.)
5G NR (New Radio) networks are not expected to be operational until at least 2020, which means 5G mobile devices won’t appear until after 5G networks are incorporated.
Small cells facilitate this pre-5G/LTE-Advanced Pro transition (LTE-A Pro) because they:
Provides greater data capacity
Helps service providers eliminate expensive rooftop systems and installation or leasing costs, thereby reducing overall costs
Helps improve cell phone performance. If your phone is closer to the small cell base station, it transmits at a lower power, which effectively reduces the power used by the phone and greatly increases its battery life.
There is a lot of discussion right now that true 5G will run on higher bandwidths, such as 28 GHz or 39 GHz. At these millimeter wave (mmWave) frequencies, small cells will also become critical because the signal cannot penetrate walls or buildings, and the coverage radius of the cell size will be less than 500 meters. In a few years, those 5G networks may exist on top of the systems used for small cells today.
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