In GSM 900, the frequency that is used to transfer the information over the air interface is around 900 MHz. Since this is not the frequency at which the information into the usable frequency band. Frequency translation is implemented by modulating the amplitude, frequency or phase of the so-called carrier wave in accordance with waveform of the input signal. Any modulation scheme increases the carrier bandwidth and hence is a limit on the capacity of the frequency band available.
In GSM, the carrier bandwidth is 200 kHz.
The modulation technique used in GSM is Gaussian Minimum Shift Keying (GMSK). GMSK enables the transmission of 270 kbit/s within 200 kHz channel. This gives bit rate of 1.3 bit/s per Hz.
In GSM, the carrier bandwidth is 200 kHz.
The modulation technique used in GSM is Gaussian Minimum Shift Keying (GMSK). GMSK enables the transmission of 270 kbit/s within 200 kHz channel. This gives bit rate of 1.3 bit/s per Hz.
No comments:
Post a Comment