Hi guys, beloy showing good explanation for the Measurement Gap in LTE and NR, thx to
Meas Gap Configuration
- In LTE system , the Meas Gap Length (MGL) is fixed, such that at least one Sync Signals ( PSS, SSS ) is included within one gap. LTE Sync Signals are transmitted at 5 ms periodicity, so the MGL of LTE is 6 ms, allowing 0.5 ms for RF module re-tuning at the beginning and end of the Meas Gap. Terminals detect the Sync Signal within the Meas Gap , identify the Physical Cell ID (PCI) and reception timing, and there after terminals perform measurements with Cell specific Reference Signals (CRS) .
- Meas Gap Lengths (MGL): 1.5 ms, 3 ms, 3.5 ms, 4 ms, 5.5 ms and 6 ms
- Meas Gap Repetition Period (MGRP): 20 ms, 40 ms, 80 ms and 160 ms
Different Types of Meas Gap in 5G NR
In 5G NR, there are following three different Meas Gap configuration –
- gapFR1: This meas gap configuration can only be applied to FR1. gapFR1 Geas Gap can not be configured together with gapUE. e.g. When UE is in RRC connected mode state with EN-DC attach and FR1 frequency needs to measure then gNB will configure either gapFR1 or gapUE.
- gapFR2: This meas gap configuration can only be applied to FR2. Similar to gapFR1, gapFR2 can not be configured together with gapUE. e.g. If UE is in RRC connected mode with EN-DC attach and FR2 need to measure then gNB will configure either gapFR2 or gapUE
- gapUE: This meas gap configuration can be applies to all frequencies i.e. FR1 and FR2. If gapUE is configured, then neither gapFR1 nor gapFR2 can be configured. With this meas gap configuration, UE can measure FR1, FR2 and non NR RAT.