15.5.5.3 Dynamic coverage configuration changes

An NG-RAN node may autonomously adjust within and switch between coverage configurations. When a change is executed, a NG-RAN node may notify its neighbour NG-RAN nodes using the NG-RAN NODE CONFIGURATION UPDATE message with the list of cells and SSBs with modified coverage included. The list contains the CGI of each modified cell with its coverage state indicator and optionally the SSB index of each modified SSB with its coverage state indicator.

The coverage state indicator may be used at the receiving NG-RAN node to adjust the functions of the Mobility Robustness Optimisation, e.g. by using the coverage state indicator to retrieve a previously stored Mobility Robustness Optimisation state. The coverage state indicator may also be used at the receiving NG-RAN node to adopt coverage configurations matching with neighbouring cells coverage configurations.

If the list includes indication about planned reconfiguration and possibly a list of replacing cells, the receiving NG-RAN node may use this to avoid connection or re-establishment failures during the reconfiguration. Also, if the sending NG-RAN node adds cells in inactive state, the receiving NG-RAN node may use this information to avoid connection or re-establishment failures. The receiving NG-RAN node may also use the notification to reduce the impact on mobility. The receiving NG-RAN node should avoid triggering handovers towards cell(s) that are indicated to be inactive.