Fronthaul HLS (Higher Layer Split)

Defines the open interconnection of a gNB-CU or ng-eNB-CU to a gNB-DU or ng-eNB-DU respectively, allowing the CUs or DUs to be supplied by different manufacturers. A fronthaul HLS interface will have both the control plane part and the user plane part. 3GPP F1 interface is an example of a fronthaul HLS interface.