What is a wave?
- A wave is the disturbance created in the medium.
- Propagates energy through the medium.
- There is no net motion of particles.
- The particles return to the original position once the wave is passed away.
- As a result only energy but not matter is propagated by the waves.
What are the different categories and types of waves?
Based on the need of medium they are classified into following types:
- Mechanical waves require medium to travel through.
- Electomagnetic waves does not require any material medium to travel through. Can travel through vaccum.
Based on the direction of particle they are classified into following types:
- Transverse waves are those in which the particles of the medium vibrate perpendicular to the direction of the propagation of the wave.
- Longitudinal waves are those in which the particles of the medium vibrate along the direction of the propagation of the wave.
What is wavelength?
- The distance between successive crests or troughs in a wave is called wave length.
- Wavelength is commonly designated by the Greek letter lambda (λ).
- As it is the distance it is measured in meters.
What is frequency?
- The number of complete cycles made by a wave in one second.
- It is commonly measured by f.
- It is measured in cycles per second which is also known as hertz.
What is frequency spectrum?
Spectrum refers to the range of frequencies of radio waves used in different wireless forms of communication.
2G, 3G and 4G:
All these numbers refer to the generations of technology used for communication.
| Parameters | 1G | 2G | 3G | 4G |
|---|---|---|---|---|
| Name | 1st Generation Mobile Network | 2nd Generation Mobile Network | 3rd Generation Mobile Network | 4th Generation Mobile Network |
| Introduced in year | 1980s | 1993 | 2001 | 2009 |
| Location of first commercialization | USA | Finland | Japan | South Korea |
| Speed (data rates) | 2.4 Kbps to 14.4 kbps | 14.4 Kbps | 3.1 Mbps | 100 Mbps |
| Special Characteristic | First wireless communication | Digital version of 1G technology | Digital broadband, speed increments | Very high speeds, All IP |
| Features | Voice only | Multiple users on single channel | Multimedia features, Video Call | High Speed, real time streaming |
| Supports | Voice only | Voice and Data | Voice and Data | Voice and Data |
| Internet service | No Internet | Narrowband | Broadband | Ultra Broadband |
| Band (Frequency) type | Narrow band | Narrow band | Wide band | Ultra Wide Band |
| Advantage | Simpler (less complex) network elements | Multimedia features (SMS, MMS), Internet access and SIM introduced | High security, international roaming | Speed, High speed handoffs, MIMO technology, Global mobility |
| Disadvantages | Limited capacity, not secure, poor battery life, large phone size, background interference | Low network range, slow data rates | High power consumption, Low network coverage, High cost of spectrum licence | Hard to implement, complicated hardware required |
| Applications | Voice Calls | Voice calls, Short messages, browsing (partial) | Video conferencing, mobile TV, GPS | High speed applications, mobile TV, Wearable devices |