Measurement Gap Calculator
LTE / 5G NR measurement gap analysis and impact assessment.
Configuration
Standard 6ms gap with 80ms repetition period
Impact analysis
Time-domain analysis
Gap schedule
Performance breakdown
Concept of Measurement Gap
In 5G NR and LTE, a Measurement Gap is a period during which the User Equipment (UE) stops transmitting or receiving data from its serving cell to perform measurements on other frequencies (inter-frequency) or other Radio Access Technologies (inter-RAT, such as transitioning between 4G and 5G).
Without these gaps, a UE with a single receiver would be unable to tune to a different frequency without losing connection to its current cell. The network carefully schedules these gaps to balance the need for mobility measurements with the requirement for continuous data throughput.
gapOffset
The gapOffset defines the starting subframe of the gap pattern within a repetition period. It is indicated in the field mgrp, and its value ranges from 0 to mgrp-1. This parameter is critical for aligning the gap with the network's measurement objects (like SSB or CSI-RS).
mgl (Measurement Gap Length)
Value mgl is the duration in ms of each measurement gap. According to Table 9.1.2-1 in TS 38.133, available lengths include ms1dot5, ms3, ms3dot5, ms4, ms5dot5, and ms6. Shorter gaps minimize throughput impact but require faster UE RF retuning capabilities.
mgrp (Repetition Period)
The mgrp is the measurement gap repetition period in milliseconds. It determines how frequently the gaps occur. Common values range from 20ms to 160ms. A shorter MGRP provides more frequent measurement opportunities but increases the overall overhead.
mgta (Timing Advance)
Value mgta is the timing advance applied to the measurement gap in ms. As per 3GPP TS 38.133, values include 0 ms, 0.25 ms, and 0.5 ms. For Frequency Range 2 (FR2/mmWave), the network typically only configures 0 ms or 0.25 ms.