Understanding LTE Carrier Frequency and EARFCN

CableFree LTE base stations use ETSI Industry Standard EARFCN to display channel numbers, rather than raw frequencies in MHz.  This may appear confusing at first glance but is the standard in LTE networks.  This article explains how to convert between LTE carrier Frequency and EARFCN numbers

Introduction

EARFCN stands for E-UTRA Absolute Radio Frequency Channel Number.In LTE, the carrier frequency in the uplink and downlink is designated by EARFCN, which ranges between 0-65535.

• EARFCN uniquely identify the LTE band and carrier frequency.
  For example Band-1 and Band-4 can have same Rx frequency 2110-2170 MHz,  but their EARFCN are different.
• EARFCN is independent of channel bandwidth.

DOWNLINK (Base Station to CPE) and UPLINK (CPE to Base Station)

The relation between EARFCN and its uplink/downlink carrier frequency is given by the equation below

• Fdownlink=FDLLow+0.1(NDL−NDLOffset)Fdownlink=FDLLow+0.1(NDL-NDLOffset)
• Fuplink=FULLow+0.1(NUL−NULOffset)

where,

NDL = downlink EARFCN
NUL = uplink EARFCN
NDLoffset = offset used to calculate downlink EARFCN
NULoffset = offset used to calculate uplink EARFCN

EARFCN of carrier frequency can be calculated with Eq-(1) or Eq-(2) using F_{DL_low}, N_Offs-DL, F_{UL_low} and N_Offs-UL given in table below.

Ref: ETSI TS 136 521-1 V11.2.0 (2013-10)

For Further Information

Please Contact Us for more information on our exciting range of solutions using LTE technology