Inter-RAT Handovers (event 2d-3a)
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•Required since 3G coverage is generally
less compared to 2G.
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It is important to have proper parameters
defined for Inter-RAT handovers (mainly UMTS-GSM).
Event 2d occurs when the 3G measured
quality is below a certain threshold for a certain period of time and this
triggers measurement on IRAT or Inter-Frequency Compressed mode measurements on
2G start after event 2d. Once event 2d is triggered, if the measured quality of
2G is above a certain threshold for a certain period of time, then event 3a
occurs.
