Once the device discovers an SS block with a received power that exceeds the received power of its current SS block by a certain threshold it reads the system information (SIB1) of the new cell to determine (among other things) if it is allowed to camp on this particular cell.įrom the perspective of device-initiated data transaction there is no need to update the network with information about the location of the device and the idle-state mobility procedure described so far would be sufficient. In order find the best cell to camp upon, the device searches for, and measures on, SS blocks similar to the initial cell search as described in Chapter 16.

Low power consumption, on the other hand, is an important aspect as a device typically spends the vast majority of time in idle state. For example, there is no need to worry about any handover interruption as there is no ongoing data transmission. One reason for using a different scheme than in connected state is that the requirements are different. The device by itself finds and selects the best cell to camp on and the network is not directly involved in the mobility events (other than providing the configuration to the device). Johan Sköld, in 5G NR (Second Edition), 2021 6.6.2 Cell ReselectionĬell reselection is the mechanism used for device mobility in idle and inactive states.

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