What is Transmission Media and its Types in Computer Network

Unguided Media

Unguided media also known as unbound transmission media refers to communication methods that do not use a physical conductor.

1. Radio Waves

Radio waves in computer networks are a form of electromagnetic radiation with longer wavelengths in the electromagnetic spectrum than infrared light. Radio waves are used for wireless communication over many distances, e.g., AM and FM radio broadcasts, TV signals, and cell networks.

2. MicroWaves

Microwaves are electromagnetic waves in the range 1 GHz to 300 GHz. They are applied in high-frequency communication, such as satellite communication and point-to-point microwave links. Applied in radar engineering and some wireless networking.

3. Infrared

Infrared transmission in computer networks uses infrared radiation to transmit information wirelessly. It works in a range of 700 nm to 1 mm. Some prominent applications are remote control, short-range wireless data transfer (e.g., some printers), and infrared data association (IrDA) for device networking.

Transmission media can be broadly categorized into guided media and unguided transmission media. Understanding their differences and similarities is essential for making informed decisions about network design and implementation.

Guided Media vs. Unguided Transmission Media

Guided media use physical pathways such as cables or fibers to transmit signals. Examples include twisted pair cables, coaxial cables, and optical fiber cables. In contrast, unguided transmission media rely on wireless communication methods, such as radiowave, microwaves, and infrared, to transmit data through the air.

Key Differences:

• Physical Path: Guided media require physical wiring, while unguided media transmit signals wirelessly.
• Interference: Guided media typically offer better protection against external interference, whereas unguided media are more susceptible to environmental factors and electromagnetic noise.
• Bandwidth and Data Transmission Rate: Optical fiber cables in guided media provide the highest bandwidth and data transmission rate, supporting both single mode and multi mode transmission. Unguided media, such as radiowave and microwaves, generally offer lower bandwidth, but can be advantageous for mobility and coverage.
• Distance: Guided media, especially optical fibers, can transmit data over longer distances with minimal signal loss. Unguided media are often limited by distance, atmospheric conditions, and obstacles.
• Line of Sight Transmission: Some unguided media, such as microwaves, require a clear line of sight between transmitter and receiver, while guided media do not have this limitation.

Criteria for Selecting Transmission Media

When choosing the appropriate transmission medium for a network, consider the following criteria:

• Bandwidth and Data Transmission Rate: Higher bandwidth is needed for applications requiring fast data transfer. For example, optical fiber cables (using LED or laser sources) support the highest rates.
• Distance: The required transmission distance influences the choice; single mode fiber is preferred for long-haul links, while multi mode fiber or twisted pair may suffice for shorter distances.
• Interference: Environments with high electromagnetic interference may benefit from shielded guided media or optical fiber.
• Installation and Cost: Guided media often require more complex installation but may provide better security and reliability. Unguided media can be more cost-effective for covering wide areas without physical infrastructure.
• Mobility and Flexibility: Unguided media are ideal for mobile or temporary setups, whereas guided media are better for permanent, stable connections.

Transmission impairment refers to the various factors and phenomena that can degrade the quality of a signal as it travels from sender to receiver. These impairments can occur in both guided and unguided media, affecting the accuracy, speed, and reliability of data communication.

Causes of Transmission Impairment

Transmission impairement are caused by a variety of factors:

• Attenuation: The step-by-step decrease of signal power due to distance, most times necessitating the use of an amplifier or repeater to bring the original signal back to its strength.
• Distortion: The alterations in the structure or timing of the signal which can be caused, among other things, by the different speeds at which signal components of different frequencies propagate.
• Noise: Noise are undesired signals that get added to the already existing data which may result in errors. Also, there is crosstalk noise (the interfering signal coming from the neighboring wires), EMI, and thermal noise.
• Interference: The external electromagnet or radio frequency signals that break the line of communication, more especially in a place where there are plenty of electronic equipments.
• Bandwidth Limitations: The limitations of the range of frequencies that a transmission medium can carry, can lower data transmission rates and thus signal compression or distortion will occur.
• Crosstalk Noise: The interference between the neighboring wires or channels, especially in the twisted pair cables and other guided media.
• Physical Barriers: The objects or materials that stop or soften signals for example walls for wireless transmission or bad-quality connectors for wired media.
• Environmental Factors: Weather changes (e.g., heavy rain, strong wind, or temperature fluctuation), water vapor, and electromagnetic storms are examples of factors that affect the signal quality, the impact is more severe in unguided media.
• Equipment Failure: Defective transmitters, receivers, or repeaters can lead to reduction in the signal quality or disconnection.
• Digital Signal Processing Errors: The inconsistencies that happen in the digital signal conversion, compression, or processing operation may eventually lead to the communication quality worsening.
• Signal Compression: The intensification of signal compression in order to fit the given bandwidth restrictions can make some of the information to disappear and lower the signal quality.

Effects of Transmission Impairment

The main effects of transmission impairment include:

• Signal Degradation: The overall weakening or corruption of the transmitted signal, leading to loss of information or increased error rates.
• Reduced Data Transmission Rate: Impairments may force networks to lower data rates to maintain reliable communication.
• Increased Error Rates: Noise, distortion, and interference can cause bits to be misinterpreted, requiring retransmissions and error correction.‍
• Unreliable Communication: Severe impairment can result in frequent data loss, connection drops, or total communication failure.

Emerging trends in transmission media are defining the future of data exchange and communication. Emerging trends are:

1. Generative AI

Text generation has yet to fully develop, but generative AI will make its way towards image creation, music composition, and even intricate design. Increasingly, there is focus put on ethical frameworks to avoid misapplication and increase accountability.

2. Advanced IoT Integration

With growth in the Internet of Things (IoT), there is growing need for effective transmission media to link many devices. This comes with low-power wide-area networks (LPWAN) and wireless sensor networks improvements. The trend is higher automation and real-time analysis in industrial use.

3. Edge Computing

Edge computing expansion is fueling requests for local data processing and transmission. This reduces latency and bandwidth usage by processing data near where it was generated instead of relying only on cloud-centric infrastructure.

4. AutoML in Machine Learning

AutoML technology is making the building of machine learning models easier, enhancing advanced analytics both accessibility and affordability, especially network optimization.

5. Robotics in Everyday Life

Networking technologies are offering the spread of robotics, and they are increasingly becoming common for household application, healthcare, and industries, leading to increased productivity and life convenience.

6. New 5G Applications

The advent of 5G is unveiling new applications in all industries ranging from telemedicine to augmented reality, extending further what can be achieved using mobile connectivity.

While transmission media play a vital role in network infrastructure and face several challenges:

• Protecting against unauthorized access and signal degradation is critical.
• High costs associated with advanced transmission media can be a barrier.
• Keeping up with technological advancements and industry standards is necessary for compatibility.

Transmission media are fundamental to the operation of modern computer networks and communication systems, each type serving specific practical uses across different industries and environments.

Wired (Guided) Media Applications

• LAN and Local Area Network: LANs (Local Area Networks) are wired (guided) media networks created using twisted pair cables, coaxial cables, and fiber optic cables. These networks link computers and other devices within a specific area, such as an office, a school, or a campus, thus allowing the fast data transfer and the sharing of resources.
• Point-to-Point Communication Links: The most common mediums for establishing point-to-point communication links are fiber optic and coaxial cables. The possibility of achieving such a goal is thus provided, being able to make a high-bandwidth and reliable connection between two different geographical locations, such as data centers or the backbones of network infrastructure.
• Medical Instruments: Optical fiber cables are being utilized in the most common medical instruments for the data transmission part of the equipment where the volume is massive and the data flow must be continuous and without interference with surroundings. Hence, the usage of these types of cables in imaging, endoscopy, and real-time diagnostics is the only logic because of their high speed and strong immunity to electromagnetic disturbances.
• Military Communications: Beside the necessity for the most modern tech for the best performance, communication over guided media like shielded cables and fiber optics is still the safest way to keep communication reliable, confidential, and free of interference under tough operating conditions.

Wireless (Unguided) Media Applications

• Wireless Local Area Networks (WLANs): Radio waves are the medium through which wireless local area networks (WLANs) function, hence devices can wirelessly connect to each other. WLANs are used to provide both flexibility and mobility and are common in homes, offices, airports as well as public locations.
• Wireless Broadband Internet: Besides radio waves, the use of microwaves is also a technology that provides wireless broadband internet. This method is especially suitable where cabling is not possible due to extreme terrains or it is too expensive to lay the cables.
• Satellite Communications: Satellite communications use microwaves for the transmission of data over extremely long distances. The support that they provide is for TV broadcasting, global internet, GPS, and emergency communications in inaccessible areas.
• Terrestrial Microwaves: Terrestrial microwaves are the source of heavy line-of-sight, high-capacity data transmissions between two fixed locations, for example, communication towers or buildings. Along with being usages for network backbones, they are also for urban infrastructural connections.
• Radar Systems: Both ground-based and airborne radar systems employ microwaves to detect, guide, and supervise the environment. Hence these systems are very important in the aviation, maritime, and defense fields.
• Weather Radar Systems: Weather radar systems use microwaves to monitor weather changes, identify storm paths, and collect important data used for weather forecasting and managing natural disasters.
• Radio Astronomy: Radio astronomy solely depends on radio waves to investigate the stars and other things that happen in space, and this is done by detecting signals from very distant stars as well as other galaxies and, thereby, slowly increasing the scientists' knowledge about the universe.

In summary,  transmission media in computer networks provides free flow data transfer and communication. Based on awareness of types, uses, and trends of the future of transmission media, organizations can make wise decisions for their networking infrastructure.

1. How does infrared transmission work in computer networks?

Infrared transmission uses light waves to transmit data over short distances, requiring a direct line of sight between devices.

2. What factors should be considered when choosing transmission media?

Considerations include distance, bandwidth requirements, cost, and security needs when selecting the appropriate transmission media for a network.

3. Why coaxial cable?

It is also known as coaxial because it has two conductors along a shared axis. The inner conductor carries the signals, and the outer shield shields against interference. The arrangement ensures safe signal transmission, especially where there is electrical noise.

4. What are the two most significant types of transmissions?

The two primary categories of transmissions are Analog and Digital. Analog uses ongoing signals to model data such as sound. Digital use binary (0s and 1s) to provide quicker, more accurate, and interference-free communication in contemporary electronic and network systems.