LTE Tutorial Long-Term Evolution 

LTE Overview

LTE (Long Term Evolution) or the E-UTRAN (Evolved Universal Terrestrial Access Network), introduced in 3GPP R8, is the access part of the Evolved Packet System (EPS). The main requirements for the new access network are high spectral efficiency, high peak data rates, short round trip time as well as flexibility in frequency and bandwidth. Figure…

LTE Tutorial Long-Term Evolution 

LTE Channels: Logical, Transport and Physical Channels Details and Mapping

What is a Channel in LTE? The information flows between the different protocols layers are known as channels. These are used to segregate the different types of data and allow them to be transported across different layers. These channels provide interfaces to each layers within the LTE protocol stack and enable an orderly and defined segregation…

LTE Tutorial Long-Term Evolution 

Hybrid Automatic Repeat Request (HARQ) in LTE FDD

HARQ stands for Hybrid Automatic Repeat Request. HARQ = ARQ + FEC (Forward Error Correction)/Soft Combining. ARQ refers to Automatic Repeat Request i.e. if sender doesn’t receive Acknowledgement (ACK) before timeout, the receiver discards the bad packet and sender shall re-transmits the packet. ARQ procedure is illustrated below : Soft Combining is an error correction technique in which the bad packets…

LTE Tutorial Long-Term Evolution 

Feature Group Indicators (FGI bits) in LTE – Rel. 8, Rel. 9 and Rel. 10

Feature Group Indicators (FGI bits) Feature Group Indicator (FGI) is a special Information Element (IE) within UE Capability Information message. The parameters other than FGI in UE Capability Information message provides information about physical layer capability e.g. UE-Category, supported Bands, Carrier Aggregation band combination etc. Feature Group Indicator provides information about radio protocol aspects. FGI information is used…