Optimal placement of femtocells will help meet demand for wireless broadband
Communication will account for $4.5 trillion in economic activity globally in 2020. But if we have only half the spectrum we need to conduct business like we are used to doing, it could negatively impact the U.S. economy by about $750 billion.
The Federal Communications Commission (FCC) projects a spectrum shortage for broadband services in the near future.
Idaho National Laboratory researcher Dr. Juan Deaton has been working on a method that seeks to solve the approaching spectrum deficit by examining how cell networks could optimize spectrum use to get the most out of the existing range. Without optimizing spectrum use, the impacts of a spectrum deficit would extend from an individual level, like dropped calls and slow connections, to global economic consequences.
Deaton uses locations of real cell towers with population data to suggest the location of femto-cells to improve cell phone coverage.
The economic impact of bringing 500 MHz of spectrum (per the FCC's National Broadband Plan) to market by 2020 is $87 billion increase in U.S. GDP; at least 350,000 new U.S. jobs; additional $23.4 billion in government revenues; and $13.1 billion increase in wireless applications and content sales.
Wireless spectrum, also called radio spectrum, is a limited resource. Measured in hertz (Hz), the highest valued radio spectrum exists between 700 megahertz (MHz) and 2,000 MHz (or 2 gigahertz). Within the radio spectrum, the wireless service providers, such as Verizon, have licensed a total 608 MHz of spectrum bandwidth for mobile wireless applications, explained Deaton. This doesn’t include the other spectrum used for things like Wi-Fi.
Proposed solution
Based on the cellular traffic demand in a given area, Deaton’s method assigns frequency channels (spectrum) to cell tower sites in order to best meet the demand for the largest amount of people.
Using Global Information System (GIS) data, Deaton’s method incorporates population information, building footprints and cell tower sites to generate a network model. The method then shows optimal usage of spectrum in the network. By taking building footprints overlaid with population data, Deaton is able to discern both where the strongest demands are and where to put additional tiny cell towers, called femto-cells.
“Adding more cells together increases the bandwidth footprint and each individual will get more data per area,” said Deaton. “The best way to optimize is to have multiple, small cell towers — then you can reuse frequencies more often.”
The research derived from Deaton's model points to the benefits of building multiple, smaller cell towers and sharing spectrum.
Despite the capabilities of the wireless optimization method, Deaton admits there are some limitations. First, putting up many tiny towers can be logistically difficult in urban areas where network companies need to work with building owners to construct more sites.
Second, the current mobile wireless broadband economy is not based on spectrum sharing, but rather on private ownership of spectrum bands. The current approach for licensing spectrum may limit new market entrants and new wireless services. Spectrum sharing could open the market to new services and the ability to optimize existing spectrum using Deaton’s method.