3GPP 38.300 v19.3.0 — the document's own text
9.2.3.4.1 General
Taught in 7. How a connection is set up, and how it is moved (TSG RAN — the group that specifies the radio, in depth).
A Conditional Handover (CHO) is defined as a handover that is executed by the UE when one or more handover execution conditions are met. The UE starts evaluating the execution condition(s) upon receiving the CHO configuration, and stops evaluating the execution condition(s) once a handover is executed.
The following principles apply to CHO:
- The CHO configuration contains the configuration of CHO candidate cell(s) generated by the candidate gNB(s) and execution condition(s) generated by the source gNB.
- An execution condition may consist of one or two trigger condition(s) (CHO events A3/A5, as defined in [12]). Only single RS type is supported and at most two different trigger quantities (e.g. RSRP and RSRQ, RSRP and SINR, etc.) can be configured simultaneously for the evalution of CHO execution condition of a single candidate cell.
- Before any CHO execution condition is satisfied, upon reception of HO command (without CHO configuration) or LTM cell switch command MAC CE, the UE executes the HO procedure as described in clause 9.2.3.2 or LTM cell switch procedure as described in clause 9.2.3.5, regardless of any previously received CHO configuration.
- While executing CHO, i.e. from the time when the UE starts synchronization with target cell, UE does not monitor source cell.
CHO is also supported for the IAB-MT in context of intra- and inter-donor IAB-node migration and BH RLF recovery.
CHO is not supported for NG-C based handover in this release of the specification.