GSM Cell ID

A GSM Cell ID (CID) is a generally unique number used to identify each base transceiver station (BTS) or sector of a BTS within a location area code (LAC) if not within a GSM network.

In some cases the first or last digit of CID represents cells' Sector ID: In UMTS, there is a distinction between Cell ID (CID) and UTRAN Cell ID (also called LCID).

It makes sense to record them separately as the RNC ID is the same for many cells, the unique element is the CID.

[citation needed] A valid CID ranges from 0 to 65535 (216 − 1) on GSM and CDMA networks and from 0 to 268,435,455 (228 − 1) on UMTS and LTE networks.

[1] A number of commercial and public Cell ID databases and services are available:

Unwired Labs LocationAPI Global Coverage Map
OpenCellID database growth monthly