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LAI/GCI/SAI Number


LAI Number

A location area identification (LAI) identifies a GSM location area uniquely worldwide, and it is used for detecting location update.

Figure 1 LAI structure

  • MCC: mobile country code, for example, 460 for China.
  • MNC: mobile network code, for example, 00 for China Mobile and 01 for China Unicom.
  • LAC: location area code. It identifies a location area. It is composed of hexadecimals of two-byte length. It is in format of X1X2X3X4, in which X1X2 is specified by the telecom management department, and X3X4 is customized by a carrier. Note that 0000 and FFFE cannot be used.
A typical LAI example is 460-00-4777.


GCI/SAI Number

  • In the GSM network, a cell is a wireless coverage area identified by the GCI. The system uses the GCI to uniquely identify a cell in the PLMN. If the omni-directional antenna is used, a cell is a BSC area.
  • In the UMTS network, a cell is a wireless coverage area identified by the SAI. The system uses the SAI to uniquely identify a service area in the PLMN. If the structure of omni-directional antenna is used, a cell is an RNC area.
The coding scheme of the GCI and the SAI are LAI + CI.
CI: It is short for cell identity. A CI is a two-byte-length hexadecimal BCD code allocated by a carrier.
A typical GCI/SAIexample is 460-00-4777-0101.