for details) includes at least the time between downlink data reception and the corre- sponding HARQ-ACK transmission in uplink. It also includes the time between uplink grant reception and the corresponding uplink data transmission, which is affected by the satellite delays. A modification of the corresponding DCI control field/format should be further investigated. Adaptive HARQ process ID. Asynchronous HARQ can be scheduled at any time slot after N sub-frames, with N being the number of HARQ processes configured. Therefore, a HARQ process ID is used to indicate which HARQ process refers to an existing transmission. Hence, it is important to study how to introduce more HARQ processes with less impact on the number of HARQ process IDs. Code block group (CBG) aggregation for reduced HARQ acknowledgements. NR supports CBG aggregation, which schedules data transmissions to span over one or multiple code blocks (CBs). For each CBG, transmission of one HARQ feedback is suf- ficient for all aggregated CBs, reducing the number of required HARQ processes and HARQ feedbacks. Therefore, an impact from longer delays in NTN needs to be consid- ered for CBG aggregation, and whether or not the aggregation among Transport Blocks (TBs) (rather than CBs) can enhance the HARQ procedure. 5.3.5.2.2 Limiting the Number of HARQ Processes or Disabling HARQ For some satellite constellations, the number of HARQ processes is too high, for example, GEO can reach 500 HARQ processes for a 1-ms sub-frame length. In this case, mechanisms are required to reduce the number of HARQ processes. In some cases, for example GEO satellite systems, disabling HARQ completely is beneficial and allows only the initial trans- mission RV0. The HARQ deactivation/(re)activation can be initiated either by a gNB or by a UE. This can be done dynamically (e.g. per transmission of one or more transport blocks) or semi-statically (e.g. by a deactivation for some time or over a geographical region). Differ- ent mechanisms and metrics are required to decide whether t