Glossary

Cells and networks

These terms describe the cells, observations and identifiers used by OpenCellID. For field names and units, see measurement fields and the download format.

Cell, sector and tower

A cell is a radio-network entity identified by its network and cell identifiers. A sector serves part of the area around a site, often using a directional antenna. A tower or mast is a physical structure that can carry antennas for several cells, technologies and operators. Antennas can also be mounted on buildings.

OpenCellID records describe cells. Counting records does not give a count of physical towers, and estimated cell coordinates are not surveyed mast locations.

Cell ID

An identifier for a cell within a mobile network, also called CID. Use the full cell identity together with the MCC, MNC, area code and radio technology for a cell lookup. Cell ID alone is not globally unique. Downloads name this field cell; lookup requests use cellid.

MCC — Mobile Country Code

Identifies the country or international network allocation associated with a mobile network. One country may have multiple MCCs; there are also shared codes for international networks. Downloads and API requests use mcc.

MNC — Mobile Network Code

Identifies a mobile network in combination with its MCC. Downloads name this field net for GSM, UMTS, LTE and NR records; API requests use mnc. For CDMA, net instead represents the SID.

LAC — Location Area Code

Identifies a location area within a mobile network. It is a network identifier, not a telephone dialing area code or a city's geographic boundary. Downloads use area; cell lookups use lac.

TAC — Tracking Area Code

Identifies a tracking area in LTE and NR networks. In cell lookups, pass it as lac; downloads store it in area. Measurement submissions also support tac as described in the measurement fields.

PCI — Physical Cell ID

A radio-layer identifier used by LTE and NR. PCI values are reused, so PCI cannot replace the full cell ID in a lookup. In LTE download records, the unit column holds PCI.

PSC — Primary Scrambling Code

A code used to distinguish UMTS radio signals. Like PCI, it is reused and does not identify a cell globally. In UMTS download records, the unit column holds PSC.

RNC — Radio Network Controller

A controller in a UMTS network. The full UMTS cell identity combines the RNC identifier with the local cell identifier; a local cell number alone may be insufficient for a match. See the database format.

eNB — Evolved Node B

An LTE base station. An eNB can serve multiple cells, so an eNB ID is not a substitute for the full LTE cell identity in a lookup.

SID, NID and BID

CDMA uses a System Identifier (SID), Network Identifier (NID) and Base Station Identifier (BID). Downloads store these as net, area and cell. See measurement fields for submission names and aliases.

MVNO — Mobile Virtual Network Operator

A provider that sells mobile service using another operator's radio network. The SIM provider's identity may differ from the observed cell's network identity. Use the observed cell's MCC and MNC; see MVNOs and roaming.

Roaming and serving network

Roaming means using a network other than the subscription's home network. The serving network is the network currently providing service to the device. Keep the MCC, MNC, area code and cell ID from the same observation when looking up a cell.

Radio technologies

Radio and access technology

radio identifies the cell's technology in lookups and downloads. Measurement submissions use act for the observed access technology. Use the values supported by the relevant endpoint; a supported value does not guarantee coverage.

See measurement access technologies for additional act values.

Measurements and location

Measurement

An observation of a cell signal at a recorded geographic position. A measurement's coordinates describe where the observation was made, which may differ from the antenna's position. Multiple observations help estimate a cell's location.

Latitude

The north–south coordinate of an observation or cell position, expressed in degrees from −90 to 90. Positive values are north of the equator; negative values are south.

Longitude

The east–west coordinate of an observation or cell position, expressed in degrees from −180 to 180. Positive values are east of the prime meridian; negative values are west.

BBOX — Bounding box

A rectangle used to select a geographic area. The OpenCellID area API expects latmin,lonmin,latmax,lonmax, in latitude/longitude order. See List cells in an area for size limits and pagination.

Range

An approximation around the estimated cell position, expressed in meters. It is not a guaranteed signal-coverage radius or an area in square meters. See range and accuracy.

Samples

The number of contributed measurements assigned to a cell. Samples do not count calls, connected phones or network traffic. See samples and traffic.

Signal strength and dBm

Signal strength describes the received radio signal. dBm expresses power relative to one milliwatt; among comparable readings, a more negative value means a weaker signal. RSSI, RSCP and RSRP are different signal measurements used by different radio technologies. ASU is an alternative integer signal representation whose scale depends on the technology. Use the units and ranges in the measurement validation rules.

TA — Timing advance

A network timing adjustment that helps a device's transmissions arrive at the expected time. OpenCellID accepts ta for GSM and LTE measurements. It is not a GPS position or a direct distance in meters; see measurement fields.

Access and files

API key or access token

A credential associated with your OpenCellID account. Use it to authenticate requests, access downloads and attribute contributions. Keep it private. See your first API request.

CSV and GZIP

CSV is a table stored as text, with fields separated by commas. GZIP compresses a file; .csv.gz is a compressed CSV file. Downloaded cell records and uploaded measurements use different CSV schemas. See the download format and CSV upload format.

Unix timestamp and UTC

A Unix timestamp represents elapsed time since 1 January 1970, 00:00 UTC. UTC is the common time reference used in our documentation. Check each field's units: download fields created and updated use seconds, while numeric measurement timestamps in measured_at use milliseconds.

Full export and daily change file

A full export is a snapshot of the cells included in a dataset download. A daily change file, also called a diff, contains changes for a daily export period. These files are not raw observations or a complete historical archive. See full exports and daily changes.