Formula for Cell ID (ECI) in LTE Network?

Cell ID in LTE is used to set or determine the physical layer (PHY) value of the signal, within Cell ID there are two values that are determined:

  1. Cell ID Group 
  2. Cell ID Sector

Cell IDs are defined as an identifier for a cell in the physical layer of the LTE network, which is basically used for different transmitter separations. 

Below settings would be visible for Cell ID:

Default: Auto

Range: Auto, Manual: 0-503

The default value is “Auto” and “Range” to set value is “0-503”.

There are 168 Cell ID groups and 3 possible Cell ID sectors so there can be 168*3 = 504 possible values for Physical Layer Cell ID values.

If the Cell ID value is set to “Auto mode”, the demodulator will automatically detect the Cell ID. When the Cell ID value is set to “Manual mode”, the PHY-layer Cell ID must be specified manually for successful demodulation.

Formula to calculate the Cell ID for (Physical) PHY Layer:

                    PHY-layer Cell ID = 3*(Cell ID Group) + Cell ID Sector

To Set the Cell ID Manually, Sync Type should be set to “C-RS”, it will disable the cell ID auto selection. It is because the demodulator requires the values of the C-RS sequence to use for synchronization and Cell ID determines these values.

Cell ID Sector shows the Zadoff-Chu Root Index that is used to calculate the Primary Synchronization Signal (P-SS) value:

Cell ID SectorZC Root Index Value

Note: Zadoff–Chu sequences are used in the 3GPP Long Term Evolution (LTE) air interface in the Primary Synchronization Signal (PSS), uplink traffic channel (PUSCH), uplink control channel (PUCCH), random access preamble (PRACH), and sounding reference signals (SRS).

What is the Cell ID Format?

Cell ID Group/Sector values are shown by the signal’s Cell ID group and Cell ID sector separated by a stroke (/).