, the UE may assume that the downlink precoder remains the same, and exploit this in the channel estima- tion process. The correlation assumption does hold between PRGs. It can be concluded that there is a tradeoff between the precoding flexibility and the channel estimation performance, that is, a large PRG size can improve the channel estimation accuracy at the cost of precod- ing flexibility. Therefore, the gNB may indicate the PRG size to the device where the possi- ble PRG sizes are two, four or the total scheduled bandwidth in terms of PRBs. It is also possible to dynamically indicate the PRG size through the DCI. In addition, the UE can be configured to assume that the PRG size is equal to the scheduled bandwidth when the scheduled bandwidth is larger than half of the active BWP. A UE may assume that the precoding granularity is PBWP(i) consecutive resource blocks in the frequency domain, where P'BWP(i) values are taken from the limited set of {2, 4, wide- band}. If P'BWP(i) is set to "wideband", the UE can expect to be scheduled with contiguous PRBs with the PRG and the use of the same precoding across the allocated resources by the gNB. If BWP(i) is set to 2 or 4, the ith BWP is partitioned into P'BWP(i) consecutive PRBs to form the PRGs. In practice, the number of consecutive PRBs in each PRG can be one or more. The first PRG size is and the last PRG size given 0; otherwise, the last PRG size is P'BWP(i) [15]. The UE may assume the same precoding is applied for any downlink contiguous allocation of PRBs within a PRG. If a UE is scheduled a PDSCH with DCI format 1_0, it can assume that PBBP(i) is equal to 2 PRBs [15]. 3.7.4 Resource Allocation for Grant-Free/Semi-persistent Scheduling In grant-free uplink transmissions, the UEs can transmit within a set of predetermined resource blocks without any explicit scheduling grants from the base station, resulting in lower control/signaling overhead and latency. However, uplink transmissions require the 404 Chapter 3 UEs to transmit within a given set of resourc