re repeated every seven DRX cycles, alternating between LTE800 and LTE2600. In the example the DRX cycle is 0.64 seconds and hence the UE performs better than the 3GPP requirement of eight DRX cycles given in Table 14.2. In the first search step of Figure 14.7 the UE detects PCIs 157 and 201 on LTE800 and PCIs 405 and 447 on LTE2600. These PCIs are then measured until the next search interval after 120 seconds, at which time two new PCIs (127, 310) are detected on LTE2600 and one new PCI (199) is detected on LTE800. Figure 14.8 shows the measurement schedule of the same UE when Sprioritysearch1 = 62 dB, that is, the UE is using the accelerated measurement schedule of higher priority layers. In this case the cell measurement interval is the same as in the case with Sprioritysearch1 = 0 dB, but the search interval is reduced from 120 to 14.72 seconds (23 DRX cycles). This can considerably speed up the reselection from 3G to LTE. Inter-RAT Cell Reselection from 2G to LTE UE inter-RAT reselection measurement scheduling from 2G to a higher priority LTE layer is very loosely defined by 3GPP. In 2G, the priority-based cell reselection measurement is VoLTE Optimization 14.72 14.72 14.72 seconds seconds seconds seconds seconds seconds seconds seconds seconds seconds seconds seconds seconds seconds pci157 pci405 pci157 pci405 pci157 pci405 pci157 pci405 pci201 pci310 pci201 pci310 pci201 pci201 pci447 pci201 pci447 pci201 pci447 pci201 pci447 pci199 pci199 pci275 pci199 pci199 pci127 pci199 pci127 pci499 pci499 pci499 pci310 pci310 pci122 pci302 Figure 14.8 Idle mode and CELL_PCH search and measurement schedule for a commercial UE when accelerated high-priority search is used (Sprioritysearch1 = 62 dB). Two LTE layers broadcast in SIB19. PCIs detected in the search steps are shown in bold not activated until the UE has received the priority-based reselection information over BCCH SI2quarter system information. This information may have to be split into multiple system information segments and hence there may be delay by se