 account the latency constraints. This is because the former is of relatively small packet size and small loading, while packet size of the latter is large to be transmitted by contention (Fig. 3.55). The semi-persistent scheduling (SPS)-based resource allocation refers to a transmission mode in which the serving base station allocates at least a part of resources and transport formats to the UE semi-statically over a certain time interval consisting of a number of TTIs. In the downlink, the semi-persistent scheduling is configured by RRC per serving cell and per BWP. Multiple configurations can be active simultaneously on different serving cells. Activation and deactivation of the downlink semi-persistent scheduling transmissions are independent among the serving cells [20]. In downlink semi-persistent scheduling, a downlink assignment is provided by PDCCH, and stored or cleared based on layer-1 signaling indicating semi-persistent scheduling activation or deactivation. A configured scheduling RNTI (CS-RNTI), which is similar to SPS C- RNTI in LTE, is configured by RRC for activation, deactivation, and retransmission. Furthermore, the number of configured HARQ processes and the periodicity of semi- persistent scheduling are signaled by RRC. When SPS resources are released by upper layers, all the corresponding configurations are subsequently released. In other words, the gNB can allocate downlink resources for the initial HARQ transmissions to UEs. The RRC defines the periodicity of the configured downlink assignments while PDCCH addressed with CS-RNTI can either signal and activate the configured downlink assignment, or deacti- vate it, that is, a PDCCH scrambled with CS-RNTI indicates that the downlink assignment can be implicitly reused according to the periodicity defined by RRC, until deactivated. After a downlink assignment is configured for semi-persistent scheduling, the MAC entity considers that the Nth downlink assignment will occur in a slot whose number meets the following criteria: s10od(1024N ) whe