CORESET is configured by the PBCH or by the controlResourceSetZero field in the PDCCH-ConfigCommon information element; otherwise, subcarrier 0 in common resource block 0. The parameter l is the OFDM symbol number within the slot. In the absence of CSI- RS configuration, the PDCCH DM-RS and SS/PBCH blocks are quasi-co-located with respect to Doppler shift, Doppler spread, average delay, delay spread, and spatial RX parameters. New Radio Access Physical Layer Aspects (Part 2) 453 The notion of wideband DM-RS has been introduced to assist the NR UE in channel estima- tion for the control channel detection (see Fig. 4.19). For each CORESET, the precoder granularity in the frequency domain is configurable between REG bundle size and the num- ber of contiguous RBs in the frequency domain within the CORESET. The UE may assume DM-RS is present in all REGs within the set of contiguous RBs of the CORESET where and when at least one REG of a candidate is mapped [6]. 4.1.3.2.2 UE Group-Common Signaling An NR gNB can simultaneously support diverse service categories and thus mitigation of the performance degradation of interrupted services is an important issue in the physical layer design. While the flexible frame structure may alleviate this problem, due to the implementation complexity and unpredictability of URLLC packet arrival times, a more elaborate solution is needed in real-world deployment scenarios. 3GPP has considered a number of solutions in the course of NR development. For infrequent URLLC transmis- sions, one can give priority to URLLC transmissions while ensuring the reliability of the other transmissions interrupted by URLLC traffic. A preemption indicator transmitted by the base station indicates which resources are used for the URLLC transmission. If the URLLC packet is stretched in the frequency domain, the URLLC transmission will interrupt the entire system bandwidth and thus degrade all data channels in use. To notify scheduled users of this event, the base station broadcasts a preemption indicator con