Wavelength in GSM

There are many different types of electromagnetic waves. These electromagnetic waves can be described by a sinusoidal function, which is characterized by wavelength. Wavelength (l) is the length of one complete oscillation and is measured in meters (m). Frequency and wavelength are related via the speed of propagation, which for radio waves is the speed of light (3 x10^8 m/s or meters per second).

The wavelength of a frequency can be determined by using the following formula:

Wavelength = Speed / Frequency

Thus, for GSM 900 the wavelength is:

Wavelength = 3×10^8 m/s / 900 MHz           

Wavelength = 300,000,000 m/s  / 900,000,000

Wavelength = 0.33 m (or 33 cm)

From this formula it can be determined that the higher the frequency, the shorter the wavelength. Lower frequencies, with longer wavelengths, are better suited to transmission over large distances, because they bounce on the surface of the earth and in the atmosphere. Television and FM radio are examples of applications, which use lower frequencies.

Higher frequencies, with shorter wavelengths, are better suited to transmission over small distances, because they are sensitive to such problems as obstacles in the line of the transmission path. Higher frequencies are suited to small areas of coverage, where the receiver is relatively close to the transmitter.

The frequencies used by mobile systems compromise between the coverage advantages offered by lower frequencies and the closeness-to-the-receiver advantages offered by use of higher frequencies.