Public:CDMA
Contents
CDMA information
General
CDMA networks exist in parallel to GSM networks. Details can be found here
The CDMA Development Group states that, as of May 2012, there are 329 operators in 121 countries offering CDMA2000 1X and/or 1xEV-DO service.
Therefore it makes sense for OpenCellID to support CDMA networks in addition to GSM networks.
The CDMA networks existing in January 2014 are listed in this document. Latest information for each county can be found here at ifast.
Here you can find out for a given network to which country it is allocated.
Here you can find out the carriee for a given SID.
A CDMA cell tower identification consits fo the following information:
- SID
- NID
- BID
System Identification (SID)
System Identification Number Allocation
ifast is the organization responsible for the allocation of ranges of SIDs to each CDMA network provider world wide. These SIDs are world wide unique, so NO (!) MNC or MCC information is needed for identifying each network. Some networks transmit in addition to the SID an MCC and/or MNC number. The OpenCellID backend ignores this information because it is not clearly specified and if present, then redundant.
System Identification conflict with GSM MNC
Some SIDs exist with an exact same MNC code for a GSM network in the same country.
In order to differentiate between these two network types it is important that each client contributing data to the OpenCellID database provides an information on which network this data has been collected. Details can be found here.
Some information regarding SIDs is also provided on Wikipedia.
(NID)
(BID)
CDMA terminology
CDMA terminology can be found here.
In this wiki page only terms are explained that are particualarily important for OpenCelID.
SID
SID/NID
SID/NID: In a CDMA network, a mobile station judges whether roaming takes place based on a pair of identity numbers (SID and NID). System Identity Number (SID) includes 15 bits. Each local mobile network is allocated with one SID and the specific number allocated to each local network is specified by the network provider. Network Identity Number is made up of 16 bits, with 0 and 65535 reserved. 0 is used to represent those base stations in a certain SID area not belonging to a specific NID area. 65535 is used to indicate that a mobile user can roam in the whole SID area. For a CDMA network side, there is no concept of NID, but an exchange number (one byte), which is used to identify the network equipment where a user is located.
