 numerologies can be separated by the configurations of the BWP. Moreover, in situations in which the numerology for a device should change - for example, a traffic type change - the device is assigned to another BWP associated with that new numerology: Overall carrier BWP # 1 BWP # 2 (numerology # 1) (numerology # 2) Figure 6.21 - Supporting different numerologies Another use case is the support of the non-contiguous spectrum. If all the BWPs defined in a cell block a certain frequency range, the network frees those resources and avoids any transmission from the network for the devices on those frequencies: Overall carrier BWP # 1 BWP # 2 Something completely unknown Figure 6.22 - Supporting a non-contiguous spectrum One final use case is forward compatibility. This is also related to the previous use case. This is basically the possibility to avoid the transmission of all the devices in a given frequency range, which could make it easier to support new features in the future without having to consider the impact on the device penetration in the network. Overall carrier Something new and not yet defiened Figure 6.23 - Supporting forward compatibility 5G Air Interface and Physical Layer Procedures - Part 3 So, BWPs are one of the main improvements for NR. We have explored at a high level how they are configured and activated and some of the main scenarios in which they can be employed. Summary In this chapter, we went through the downlink and uplink physical channels and signals for NR. Although certain aspects are taken from LTE, we still covered the similarities and differences for NR. We discussed channel coding schemes, LDPC code, and polar coding. We finished the chapter by evaluating the use cases of BWPs. As such, this chapter has fully covered the NR air interface and physical layer procedures. Next, we'll look at the packet core procedures in 5G. Packet Core Procedures In this chapter, we will consolidate the concepts and fundamental knowledge from the previous chapters and map them to real 5G system pro