Optic fiber VS. Satellite communication

Communication

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Optic fiber communication and satellite communication are the leading technologies which are revolutionizing the world of telecommunications. Both technologies have their advantages and limitations which make them suitable for certain type of applications. This article will provide an overview of optic fiber and satellite communication technologies and present a comparison of the features and related issues.

Optic Fiber Communication

Optic Fiber communication transmits information by sending pulses of light (using laser) through an optic fiber. The low signal loss in optic fibers and high data rate of transmission systems, allow signals with high data rates (exceeding several Gbps) to travel over long distances (more than 100 km) without a need of repeater or amplifier. Moreover, using wavelength division multiplexing (WDM) allows a single fiber to carry multiple signals (upto 10 different signals) of multi-Gbps transmissions. Optic Fiber communication offers extremely high bandwidth, immunity to electromagnetic interference, non-existent delays and immunity from interception by external means. In the 1980s and 1990s, the continents were linked together using undersea optic fiber bringing about a paradigm shift in the global telecommunications.

These advancements in optic fiber communication has resulted in decrease of satellite communications for several types of communications. For instance, transmission between fixed locations or point-to-point communications, where large bandwidths are required (such as transoceanic telephone systems) are made through optic fiber instead of using satellite communication. Optic Fiber communication is also used to transmit telephone signals, Internet communication, LAN (Gigabit LAN) and cable television signals.

Satellite Communication

Satellite communications use artificial satellites as relays between a transmitter and a receiver at different locations on Earth. Satellite systems allow users to bypass typical carrier offices and to broadcast information to multiple locations. Communications satellites are used for radio, TV, telephone, Internet, military and other applications. There are more than 2,000 satellites around Earth’s orbit, being used for communication by both government and private organizations.

Communication Satellites are LOS (line-of-sight) microwave systems with a repeater. These satellites rotate around the earth with the speed of earth and are known as geostationary satellites. The limitations of antenna size also limits focusing capability making the coverage for a single satellite transmitter very large. This makes satellite communication ideal for TV and radio services as the signal has to flow from a single point to many points in a single direction. The large distance of satellites from the earth (about 22,300 miles) results in delays which adversely effects two-way communication like mobile conversations. Low earth orbit satellites can be used for two-way mobile communication because less power is required to reach those satellites.

Comparison of Optic Fiber and Satellite Communication

  • Bandwidth and data rates: Optic Fiber supports higher bandwidth and data rates as compared to satellite.

  • Mobility: Optic Fiber cannot be used in mobile applications and is suitable for fixed locations. Satellite communication is suitable for mobile applications.

  • Reliability: Fiber Optic communication is more reliable than satellite.

  • Terrain: Fiber optic is more suitable for urban areas and plains where digging / laying is easier. Satellite communication is suitable for remote areas and rough terrains like mountainous areas.

  • Delay: Optic fiber has minimum or no delays making is suitable for real time applications. Satellite communication has an inherent propagation delay.

  • Interference: Optic fiber has less or no Electromagnetic Interference EMI whereas Satellite communication has high EMI.

  • Coverage: Satellites are suitable for providing point to multi-point services with large coverage like TV and radio.

  • Cost:

    • Initial Cost: Depends on the size of network and whether the user wants to deploy complete network or part of it and lease the rest.

    • Recurring Cost: Satellite has higher recurring cost than optic fiber communication.

Serial

Feature

Optic Fiber

Satellite

1

Bandwidth Higher Lower

2

Data rates Higher Lower

3

Mobility Not mobile Mobile

4

Reliability Higher Lower

5

Terrain Urban areas, plains Mountainous terrain and remote areas

6

Delay No delay Delay in transmission

7

Interference No EMI High EMI

8

Cost Lower recurring cost Higher recurring cost