CORESET-precoder-granularity. pdcch-DMRS-ScramblingID is the PDCCH DM-RS scrambling initialization. The DM-RSs associated with a given PDCCH candidate are mapped to every fourth subcar- rier in a REG, that is, the reference signal overhead is one-fourth. This is a denser reference signal pattern relative to LTE, which has a reference signal overhead of one-sixth; however, an LTE device can interpolate channel estimates across time and frequency as a result of cell-specific reference signals common to all devices and present regardless of control chan- nel transmission. The use of a dedicated reference signal per PDCCH candidate is advanta- geous, despite the slightly higher overhead, since it allows different type of device- transparent beamforming schemes. By using a beamformed control channel, the coverage and performance can be enhanced compared to the non-beamformed control channels in LTE. This is an essential part of the beam-centric design of NR [14]. When attempting to decode a PDCCH candidate occupying certain number of CCEs, the device can compute the REG bundles that constitute the PDCCH candidate. Channel esti- mation must be performed per REG bundle as the network may change precoding across REG bundles. In general, this results in sufficiently accurate channel estimates for PDCCH detection. However, it is also possible to configure the device to assume the same precoding across contiguous resource blocks in a CORESET, thereby allowing the device to perform frequency-domain interpolation of the channel estimates. This also implies that the device may use reference signals referred to as wideband reference signals outside the PDCCH region that it is trying to detect (see Fig. 4.19). The QCL concept is also applicable to the reference signals. If the UE has a priori knowledge about the QCL of two reference signals, it can exploit this property to improve the channel estimation and to manage different receive beams at the device. If no QCL is configured for a CORESET, the UE assumes that PDCCH candidate