BWPs

In this last section of this chapter, we will cover another concept introduced in NR, which is the BWPs. This concept is new in NR and very powerful for a few interesting and important use cases.

In this section, we will learn what BWPs are and how they are configured, activated, and deactivated. We will also describe the main use cases for BWPs to better understand their importance in the NR physical layer.

Defining a BWP

So, let’s start by defining what a BWP is. A BWP is a set of contiguous PRBs with nested bandwidths where the devices are only allowed to transmit or receive. Each BWP has its own configuration with a specific numerology to use and a set of reserved resources for which transmission is not allowed. Devices always operate using BWPs. This means that at least one initial BWP must be defined by the PBCH so that all devices can access it. This initial BWP will also contain the CORESET and PDSCH for the RMSI. However, a BWP does not need to contain...