Frequency Resource of GSM System

lGSM consists of GSM900 and DCS1800 according to different system frequency bands. GSM is a duplex system.  According to the GSM protocol, the uplink frequency band (MS to BTS) of GSM 900 is 890MHz-915MHz, and the downlink frequency band (BTS to MS) is 935MHz-960MHz, the duplex distance is 45MHz; the uplink frequency band of GSM1800 is 1710MHz-1785MHz, while the downlink frequency band is 1805MHz-1880MHz, the duplex spacing is 95 MHz. In different countries, the specified frequency resource is allocated to different operators, each operator may only have a part of resources in the entire frequency band. With the limited resources, frequency planning plays an important role in maximizing the system capacity and service quality to achieve the goal and thus maximize the benefit of the operator.

Frequency Resource of GSM System

According to GSM 05.05 (version 8.5.0)， Frequency bands and channel arrangement :

i)  Standard or primary GSM 900 Band, P GSM:

-for Standard GSM 900 band, the system is required to operate in the following frequency band:

-  890 MHz to 915 MHz: mobile transmit, base receive;

-  935 MHz to 960 MHz: base transmit, mobile receive.

ii)  Extended GSM 900 Band, E GSM (includes Standard GSM 900 band):

-for Extended GSM 900 band, the system is required to operate in the following frequency band:

-  880 MHz to 915 MHz: mobile transmit, base receive;

-  925 MHz to 960 MHz: base transmit, mobile receive.

iii)  Railways GSM 900 Band, R GSM (includes Standard and Extended GSM 900 Band);

-for Railways GSM 900 band, the system is required to operate in the following frequency band:

-  876 MHz to 915 MHz: mobile transmit, base receive;

-  921 MHz to 960 MHz: base transmit, mobile receive.

iv)  DCS 1800 Band:

-for DCS 1800, the system is required to operate in the following band:

-  1710 MHz to 1785 MHz: mobile transmit, base receive;

-  1805 MHz to 1880 MHz: base transmit, mobile receive.

v)  PCS 1900 Band:

-  for PCS 1900, the system is required to operate in the following band:

-  1850 MHz to 1910 MHz: mobile transmit, base receive;

-  1930 MHz to 1990 MHz base transmit, mobile receive.

NOTE 1:  The term GSM 900 is used for any GSM system, which operates in any 900 MHz band.

NOTE 2:  The BTS may cover a complete band, or the BTS capabilities may be restricted to a subset only, depending on the operator needs.

Operators may implement networks which operates on a combination of the frequency bands above to support multi band mobile terminals which are defined in GSM 02.06.

The carrier spacing is 200 kHz.

Frequencies are in MHz.

The carrier frequency is designated by the absolute radio frequency channel number (ARFCN). If we call Fu(n) the frequency value of the carrier ARFCN n in the uplink band, and Fd(n) the corresponding frequency value in the downlink band, we have the table above.