t consider the propagation delay, for instance, for the uplink/downlink resource allocations. Different to terrestrial networks, there is a large delay between measurement and reporting of the downlink channel quality, which is reported via Channel State Information feedback on the Physical Uplink Control Channel (PUCCH), and the actual downlink scheduling decision is indicated to the UE via Downlink Control Information on the Physical Downlink Control Channel (PDCCH). In the uplink, this effect might even be more severe, because of the additional delay produced by uplink Scheduling Requests (SRs) and Buffer Status Reports (BSRs) that have to be received by the gNB before a scheduling decision can be made. One possible way to mitigate this issue is an uplink preconfiguration of resources, which can reduce the uplink scheduling delay in NTN. Furthermore, link adaptation algorithms in the MAC layer can also be affected by the large round-trip time. Examples of algorithms affected are: adaptive coding and modula- tion, uplink power control, TA, adaptive multiple-input multiple-output (MIMO), and outer loop link adaptation. While a scheduler in a terrestrial network might track the fast fading, it might not be feasible in NTN. The importance of an accurate link adaptation will be even bigger if the usage of a HARQ retransmission protocol is not feasible. At least for the GEO satellites, the propagation delay will prevent the use of HARQ for high-rate eMBB applications. The round-trip time required for the retransmissions to arrive at the receiver will become too large to store all the quan- tized receive symbols of the erroneous packets in the HARQ protocol. Therefore, an NTN system without HARQ may need to operate at a significantly more conservative block error rate (BLER) to avoid a large number of retransmissions at higher layer, for example, 1% BLER in a system without HARQ versus 10-20% BLER in a system with HARQ. 5.3.4.2 NR Layer 2 Enhancements for NTN While the previously described link adaptation and schedul