TABLE OF CONTENTS GSM radio is wireless communication system that divides geographic areas into small radio areas (cells) that are interconnected with each other. Each cell coverage area has one or several transmitters and receivers that communicate with mobile telephones within its area.
GSM radio systems operate in a specific frequency band (or frequency bands) that has been allocated to the system. The radio frequency channel that the system operators may be reused at different cell sites according to a frequency plan. User share each radio channel using a combination of frequency division and time division multiple access.
Frequency allocation is the amount of radio spectrum (frequency bands) that assigned (allocated) by a regulatory agency for use for specific types of radio services.
The original GSM system was assigned two 25 MHz bands at 890 915 MHz (mobile telephone transmit) and 935 960 MHz (base transceiver station transmit) that are separated by 45 MHz. Because each GSM radio channel has a frequency bandwidth of 200 kHz, this divides into 125 radio channel carriers. In some systems, the entire frequency band may not be available, and in other systems, radio channels may be divided among multiple cellular service providers.
Since its creation, many countries have authorized additional frequency band for GSM system. The GSM frequency band for PCN (DCS 1800) is 1710 1785 MHz (subscriber unit transmit) and 1785 1880 MHz (base station transmit) separated by 75 MHz. Each PCN frequency band is divided into 375 radio channels of 200 kHz each.
Figure 1.6 shows the...
