In some cases the first or last digit of CID represents cells' Sector ID:
value 0 is used for omnidirectional antenna,
values 1, 2, and 3 are used to identify sectors of bisector or trisector antennas.
In UMTS, there is a distinction between Cell ID (CID) and UTRAN Cell ID (also called LCID). The UTRAN Cell ID (LCID) is a concatenation of the RNC-ID (12 bits, ID of the Radio Network Controller) and Cell ID (16 bits, unique ID of the Cell). CID is just the Cell ID. The concatenation of both will still be unique but can be confusing in some cellid databases as some store the CID and other store 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]
Cell ID databases and services
A number of commercial and public Cell ID databases and services are available:
Only a small portion of the database can be downloaded and for private use only: the measurements where the crowd users accepted the "Creative Commons Namensnennung-Nicht-kommerziell-Weitergabe unter gleichen Bedingungen 3.0 Deutschland" license
Mozilla Location Service - an open service which lets devices determine their location based on network infrastructure like WiFi access points and cell towers