Cell ID Definitions Webinar

Andy Orriell

11/01/2019

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]