Satellite Communication FAQ's
Content provided with permission from Satellite Industry Association (SIA)

What are the Features of Satellite?

• Capable of transmitting and receiving Voice, Data, Video, and Internet. Highly Survivable (Physical Survivability and Robustness)
• Independent of Terrestrial Infrastructure
• Able to Provide The Load Sharing and Surge Capacity Solution for Larger Sites
• Best for Redundancy: They add a Layer of Path Diversity and Link Availability

What can Satellite be used for?

• Backup communications when terrestrial infrastructure is damaged, destroyed, or overloaded by interconnecting widely distributed networks
• Providing interoperability between disparate systems and networks
• Providing broadcasting services over very wide areas such as a country, region, or entire hemisphere
• Providing connectivity for the “last mile” in cases where fiber networks are simply not available
• Providing mobile/transportable wide- band and narrow-band communications
• When natural disasters or terrorist attacks occur, Satellites are the best and most reliable platform for communications in such situations — fiber networks or even terrestrial wireless can be disrupted by tsunamis, earthquakes, or hurricanes. Satellites are instant infrastructure.

What are the Benefits of Using Satellite?

• Ubiquitous Coverage: A group of satellites can cover virtually the Earth’s entire surface.
• Instant Infrastructure: Satellite service can be offered in areas where there is no terrestrial infrastructure and the costs of deploying a fiber or microwave network are prohibitive. It can also support services in areas where existing infrastructure is outdated, insufficient, or damaged.
• Independent of Terrestrial Infrastructure: Satellite service can provide additional bandwidth to divert traffic from congested areas, provide overflow during peak usage periods, and provide redundancy in the case of terrestrial network outages.
• Temporary Network Solutions: For applications such as news gathering, homeland security, or military activities, satellite can often provide the only practical, short-term solution for getting necessary information in and out.
• Rapid Provisioning of Services: Since satellite solutions can be set up quickly, communications networks and new services can be quickly recovered and reconfigured. In addition, you can expand services electronically without traditional terrestrial networks. As a result, you can achieve a high level of communications rapidly without high budget expenditures.

Satellite Communications Technology Terms & Definitions

ANTENNA
A device for transmitting and receiving signals. An antenna is part of an Earth Station.
BACKHAUL
A terrestrial communications channel linking an earth station antenna to a local switching network or population center.
BANDWIDTH
A measure of spectrum (frequency) use or capacity. For instance, a voice transmission by telephone requires a bandwidth of about 3000 cycles per second (3KHz).
CHANNEL
A frequency band in which a specific broadcast signal is transmitted. Channel frequencies are specified in the United States by the Federal Communications Commission.
DOWNLINK
The link from the satellite down to the Earth Station.
EARTH STATION
The buildings, hardware, software and antennas used to communicate with a satellite.
FDMA
Frequency Division Multiple Access. A way of sharing a channel by assigning different frequencies to different users.
FOOTPRINT
The area of the Earth’s surface from which an Earth Station can transmit to or receive from a particular satellite.
FREQUENCY BANDS
Internationally, frequencies are divided into well-defined bands. For satellites, the relevant bands are:
L-Band
As defined by IEEE std 521, the frequency range from 1 to 2 GHz. The L-band term is also used to refer to the 950 to 1450MHz frequency range used for mobile communications. L-band is used for Mobile Satellite Services and offers good penetration through adverse weather conditions and foliage.
C-Band
The frequency range from 3.7 to 6.2 GHz. Transmissions are less affected by atmospheric conditions such as snow and rain. However, C-band transmissions have low power, so Earth Stations must be rather large to compensate dish size. Applications include public switched networks and Internet trunking.
X-Band
The frequency range from 8.0 – 12.0 GHz. The X-band frequency enables high power operations with very small terminals. Applications include COTM, manpacks, emergency communications and airborne and shipboard platforms. X-band is also less vulnerable to rain fade and adjacent satellite side lobe interference than other frequencies.
Ku-Band
The frequency range from 11.7 to 14.5 GHz. Ku-band has higher power than C-band allowing for smaller dishes to be used. However, the higher frequency of Ku-band makes it more susceptible to adverse weather conditions than C-band. Applications include VSAT, rural telephony, satellite news gathering, videoconferencing, and multimedia.
Ka-Band
The frequency range from 17.7 to 21.2 GHz. Has a higher power than Ku-band allowing for smaller dishes to be used and therefore, will be used for high-bandwidth interactive services such as high-speed Internet, videoconferencing, and multimedia applications. Ka-band transmissions are more sensitive to poor weather conditions than Ku-band.