Content:
• Explain the formats of global cell identities
• Explain the Chorus columns relating to Cell
IDs
• Define terminology
• Demonstrate how ECIs are calculated
Global Cell Identifiers
• Each cell site is assigned a global identifier which is unique to
that cell site – this means that any cell site on any network in
the world can be individually identified
• The technology (2G, 3G or 4G)of each cell site dictates the
format of the cell identity
2G Global Cell Identity Format
• A cell site on the 2G (GMS) network is formatted as follows:
MCC(Mobile
Country
Code)
MNC (Mobile
Network
Code)
LAC (Location
Area Code)
CI (Cell ID)
234/235 30/33
20 (Not on 2G)
15
10
2G Global Cell Identity Format
• A UK cell site on the Vodafone 2G (GMS) network would
look like this:
MCC(Mobile
Country
Code)
MNC (Mobile
Network
Code)
LAC (Location
Area Code)
CI (Cell ID)
234 –15 - 08258 – 27678
Or
GBR – VF - 08258 - 27678
3G Global Cell Identity Format
• A cell site on the 3G (UMTS) network is formatted as follows:
MCC(Mobile
Country
Code)
MNC (Mobile
Network
Code)
RNC (Radio
Network
Controller
ID)
CI (Cell ID)
RNC: Radio Network
Controller. Used to
manage a number of
Node Bs – This Value
appears in the LAC column
in raw data
4G Global Cell Identity Format
• A cell site on the 4G (LTE) network is formatted as follows:
MCC(Mobile
Country
Code)
MNC (Mobile
Network
Code)
ECI (E-UTRAN
Cell ID)
The ECI is formed by
combining two identifiers:
The eNodeB (Base Station)
ID and the Cell ID (This is
best thought of as the
Sector Code)
4G Global Cell Identity Format
• 4G Network specific Local Cell ID/Sector Numbering:
Sector 1
Sector 2
Sector 3
EE VF H3G O2
Sector 1 000 10 0 110
Sector 2 001 20 1 120
Sector 3 002 30 2 130
EG – EE Raw data gives 4G
cell ID as 15258000.
eNodeB = 15258 Cell ID =
000. We can see this Cell ID
relates to Sector 1
Cell ID Related Columns in Chorus
• Chorus contains a number of columns within the events
schedule that relate to Cell ID information in order to provide
the user the opportunity to display the level of information
that they wish:
Cell ID Related Columns in ChorusColumn Title Explanation
LAC/eNodeB Location Area Code (2G/3G) – IDs an area
containing a number of base stations (Valid
values 0-65535). eNodeB – 4G LAC equivalent
(Valid values 0-1048575)
Cell ID An identifier used to identify a cell tower or sector
on a cell tower within a LAC
Cell Site Reference This is a combination of LAC and Cell ID as per
Global Cell Identity convention (2G/3G). This
column can also include the ECI (4G)
Raw Cell Identifier This is the exact cell ID information that appears
in the raw data
Technology This states whether the Cell Site is 2G, 3G or 4G
ECI E-UTRAN cell identifier – Only applicable on 4G
Network. This is a combination of eNodeB and
Cell ID
SAC Service Area Code – This is primarily in relation to
“Stacked Cells” (eg Cell Sites of different
generations on the same mast). SACs allow
operators to group cells in an area that provide,
for example the same service
Calculating ECIs
• Some data sets do not show the ECI and some do not show the constituent parts, however, it is possible to calculate these values
• This is done by using a Binary Concatenation. We know that the ECI = eNodeB + Cell ID so, for example we have an eNodeB = 13428 and a Cell ID = 002 or 2
13428 in binary = 11010001110100 – padded to 20 Bits = 00000011010001110100
2 in binary = 10 – padded to 8 bits = 00000010
Binary Concatenation = 0000001101000111010000000010
Convert binary concatenation to decimal = 3437570
Therefore, the ECI = 3437570
Calculating ECIs
• We can also do this as a Hexadecimal conversion. We know that the ECI
= eNodeB + Cell ID so, for example we have an eNodeB = 13428 and a
Cell ID = 002 or 2
13428 in Hexadecimal = 3474
2 in Hexadecimal = 2
Hexadecimal Concatenation = 347402
Convert Hexadecimal concatenation to decimal = 3437570
Therefore, the ECI = 3437570
Network Specific Representations in
Chorus
• Chorus extracts the LAC and Cell ID from the `Cell ID` column in the raw.
In 2G and 3G data the last 5 digits are the Cell ID. The digits before this
represent the LAC
Network Specific Representations in
Chorus
• Guidance suggests that for 4G cells, the cell ID presented in raw data is
the eNodeB and the cell ID presented in separate decimal ID format
• A 4G cell ID in the raw of 13428002 should therefore be interpreted as: •
eNodeB ID - 13428 • local Cell ID – 002
• Chorus uses the eNodeB and the cell ID to calculate the ECI value, using
binary concatenation described previously
• Chorus then shows this ECI value for 4G cells in the new Cell Reference column in Data Dashboard
Network Specific Representations in
Chorus
• For H3G 4G/LTE towers, the "Cell ID" in the raw data is actually the ECI,
the "LAC" is the TAC and should be overwritten with the extracted values
from the ECI
• TAC is the Tracking Area Code. Each ECI is unique on a network on its
own and does not require TAC which is the 4G equivalent of a LAC
• Chorus decodes the ECI and this creates the eNodeB and the correct
cell ID, using the binary concatenation described previously
• Chorus populates the Cell ID column and eNodeB with the correct
decoded values from the ECI which is in the original raw data
Network Specific Representations in
Chorus
• In this example, the cell is the ECI and the LAC is actually the TAC. We
know it’s 4G as the data source is VOLTE
• In Chorus, the ECI is populated with the “First Cell” column and the eNodeB
and Cell ID are “reverse calculated”:
ECI - 80200 = 10011100101001000
01001000 = 72 (Cell ID) & 100111001 or 00000000000100111001 = 313 (eNodeB)
Network Specific Representations in
Chorus
• Chorus extracts the LAC, Cell ID (for 2G/3G cells) and ECI (for 4G cells)
from the respective columns in the raw
• If all three are present then Chorus will verify they match with each other
by decoding the ECI to get the LAC and cell ID (and comparing to the
LAC and cell ID in the raw data). If they do not match, Chorus will warn
the user via a Process Warning
• If one of these values is missing, Chorus will calculate it using the values that are present
Network Specific Representations in
Chorus
• In Vodafone Raw data there is a "Location Identifier" column which
contains a reference in the format GBR-VF-123-45678 etc. Chorus uses
this location identifier to look up the location information from the cell site
location table at the bottom of the data (or sometimes in a separate
file). Chorus will pull across the cell ID etc from this table (of note, for 4G
cells the cell ID is actually the ECI and Chorus will decode the ECI to give
the correct cell ID)
• In the rules for Vodafone (both Simplified and RAW), we will examine the
Cell ID. If it is a valid Cell ID for the type of technology (i.e. LAC for
2G/3G, eNodeB for 4G), then we allow it through. If it's a number, but not
a valid one, we mark it as a processed warning
• If it's a Location Identifier, we then decode it. By this we mean we break
down the location identifier into its component parts. For 2G/3G cells this
will be GBR-VF-[LAC]-[Cell ID]. For 4G cells this will be GBR-VF-[TAC]-[ECI]