s spectrum, from both complexity and spectrum efficiency standpoints. However, a wideband carrier introduces a power consumption challenge for mobile devices. To mitigate this, 5G NR features BWP operation in both the DL and UL, which allows one to adapt the bandwidth used according to the need, thereby mitigating the modem power consumption. BWP supports the following tech- niques to reduce the modem power consumption: Bandwidth adaptation for connected mode 15 DRX: discontinuous reception whereby the UE only wakes up at set intervals (i.e. DRX cycle) to monitor paging. 13.5 Wider Bandwidth Operation and Modem Power Consumption BWP configuration & activation Active BWP switch Active BWP switch by RRC signaling by DCI by DCI or timer 1-slot periodicity 2-slot periodicity 1-slot periodicity 2-slot periodicity PDCCH monitoring Intial Access Connected Mode Figure 13.13 Example illustration of DL BWP operation in single wideband carrier. Adaptation of PDCCH monitoring periodicity for connected mode Narrow bandwidth for idle mode Figure 13.13 illustrates an example how BWP operation can be used to support the above power saving techniques in the DL. When a mobile device performs an initial access or switches from idle mode to connected mode, it starts with an initial narrow DL BWP with a bandwidth of 20 MHz. Once in connected mode, dedicated DL BWP configurations (i.e. narrow DL BWP #1 of 20 MHz and wide DL BWP #2 of 100 MHz) are signaled to the mobile device by the network. The network simultaneously activates DL BWP #1. When there are data packets to be transmitted, the network switches the modem's active DL BWP from DL BWP #1 to DL BWP #2 via DCI for low latency. When there are no data packets to be transmitted to the device, the modem's active DL BWP is switched back from DL BWP #2 to DL BWP #1. When the mobile device switches to idle mode from connected mode, it reverts back to using the initial DL BWP. In Rel-15 5G NR, three ways of changing the active BWP are supported: higher-layer signaling (i.e. RRC signalin