In 2010, the U.S. Federal Communications Commission (FCC) predicted that consumer wireless communications demand would begin to exceed the amount of available wireless spectrum by 2014. This year, mobile data usage grew an astonishing 250 percent according to the Mobile Future communications consortium. The world is on the fast track to running out of wireless spectrum, and the world could experience major social and economic consequences.
Satellite communication has to be an international priority. When weather and warfare knock out the PSTN and cellular communications, satellite terminals and satphones keep connections alive. Fortunately, the satellite industry is taking some important steps toward spectrum efficiency, and the industry is working with governments to solve the spectrum shortage.
How Wireless Spectrum Works
People can visualize the wireless spectrum by looking at the radios in their cars. Listening to 103.7 FM is the same as listening to a station that broadcasts at 103.7 MHz. Like radio station signals, all wireless communication signals including cell phones, satellite signals and television broadcasts travel over frequency bands through the air. These wireless signals have to travel on different bands in the same geographic area so that they don’t interfere with one another.
The FCC tracks what signals and carriers are using certain frequencies, and the agency issues licenses to different companies that want to use available spectrum. Terrestrial mobile carriers, for example, use spectrum in the 700 Mhz to 2.6 GHz ranges. These carriers need to expand their capacity to meet customers’ demands for data. However, most of the spectrum allocated to mobile carriers is already being used.
Satellite signals travel in a range between about 1.467 GHz and 30 GHz. Different frequencies are optimal for different climates and different uses. For example, a satellite sending signals through areas of heavy rainfall in the Amazon would use a low frequency in the L-, C- or S-band because lower frequencies aren’t as severely affected by rainfall. Alternatively, higher frequency bands like the Ka- and Ku-bands are best for sending focused beams and enabling small antenna usage.
The Problem With Sharing
Many countries have started promoting the idea that any type of wireless device should be able to provide any wireless service in any given frequency. Companies that develop these capabilities will stay around, and those that choose not to adapt will lose relevance. Unfortunately, satellite communications and terrestrial communications, like cellular communications, can’t switch out of their optimal frequencies without causing signal degradation and interference.
Also, a cellular tower may serve a contained geographic area within a country while a single satellite can enable services across multiple countries. If every country begins to sell spectrum to the highest bidder without regard for optimal frequencies, then services may no longer be compatible across borders. Once a satellite is launched, its location can’t be changed, and it may stay in orbit for up to 15 years. Because satellites are so crucial in emergency situations, governments must keep frequency bands compatible across borders.
Satellite providers continue working together to improve efficiency. For example, the satellite industry led the transition from analog to digital broadcasting. Digital multiplies the number of available channels in a frequency band, increasing efficiency. Also, satellites from different orbital positions share and reuse frequency as their positions change, and multiple transponders can use the same frequency bands.
Other solutions involve creating a hybrid communications infrastructure that combines satellite and terrestrial technologies. Satellites, for example, could take on more mobile traffic without requiring cellular carriers to build out their existing infrastructure. In addition to saving money for terrestrial carriers, leveraging satellite communications would also reduce the communications industry’s carbon footprint. However, for hybrid technologies to work without generating signal interference, satellite operators would have to control terrestrial technology components.
Journey into Pakistan, where people experience frequent natural disasters, like earthquakes, along with frequent recurrent military skirmishes. Pakistanis also cope with daily rolling power blackouts, and cellular towers and antennas require electricity to operate.
Areas like Pakistan need satellite phones to maintain their connections both to each other and to the outside world. Pakistan is just one example of why governments should cooperate to prioritize satellite spectrum allocation.
About the Author
Steve Manley is the president of Globalcom Satellite Communications , a leading distributor of satellite phones for both purchase and rental.
Image by Ben Rogers from Flickr Creative Commons