Broadband Internet Access

Satellite Internet

This employs a satellite in geostationary orbit to relay data from the satellite company to each customer. Satellite Internet is usually among the most expensive ways of gaining broadband Internet access, but in rural areas it is often the only viable option. However costs have been coming down in recent times to the point that it is becoming more competitive with other high speed options.

Satellite Internet also has a high latency problem caused by the signal having to travel 22,000 miles (35,000 km) out into space to the satellite and back to Earth again. The signal delay can be as much as 500 milliseconds to 900 milliseconds, which makes this service unsuitable for applications such as multiplayer Internet gaming or live interactive access to a distant computer, but tolerable for just basic email access and web browsing.

There is no simple way to get around this problem. The delay is primarily due to the speed of light being only 186,000 miles per second (300,000 km/second). Even if all other signalling delays could be eliminated it still takes the electromagnetic wave 233 milliseconds to travel from ground to the satellite and back to the ground, a total of 44,000 miles (70,000 km) to travel from you to the satellite company.

Since the satellite is being used for two-way communications, the total distance increases to 88,000 miles (140,000 km), which takes a radio wave 466 ms to travel. Factoring in normal delays from other network sources gives a typical connection latency of 500-700 ms. This is far worse latency than even most dialup modem users experience, at typically only 150-200 ms total latency.

Reducing satellite latency

The only real alternative is to use satellites in much lower orbit very close to the Earth, to shorten the travel distance. Such orbital paths are no longer geostationary, and so would require a large number of satellites in orbit so that at least one is visible in the sky at all times. Communication dishes could no longer be fixed, and would either need some way to track the satellites as they move across the sky, or to work in an omnidirectional manner without causing interference for anything else. The lower orbits would also subject the satellites to a slight drag effect from the upper atmosphere, requiring a need for some way to boost the orbits back up as the satellites gradually slow down.

A theoretical alternative to satellites that is being explored is the use of ultralight solar-powered airplane (see the Helios Prototype) or an airship (see Stratellite) that could fly in a continuous a circling path perhaps 70,000 feet (20 km) high. These would act as flying satellites, providing high-speed service to customers below the aircraft. Since the roundtrip signal distance would only be 30 miles, the latency caused by the speed of light is an almost insignificant 0.1 ms under the craft, and 2 ms at the edge of the covered area, at a 300 km (200 miles) distance. (Note that the aircraft work is still in the experimental stages.)