What is a bandwidth part?

One of the basic concepts in 5G NR is bandwidth part (BWP), which is, at a high level, a set of contiguous resource blocks configured inside a channel bandwidth .

A UE can be configured with up to four bandwidth parts in the downlink, with a single downlink bandwidth part being active at one time.

According to 38.211 4.4. 5, A carrier bandwidth part is defined as follows : Carrier Bandwidth Part is a contiguous set of physical resource blocks,selected from a contiguous subset of the common resource blocks for a given numerology(u) on a given carrier .

CRB refer to common resource block , i.e. BW of 5G divided into multiple CRB used for BWP. PRB refer to block assigned to user by scheduler. In 5G we have VRB to PRB mapping which depends on Downlink resource allocation type, it can be interleaved or non inter leaved.

A Bandwidth Part (BWP) is a contiguous set of physical resource blocks (PRBs) on a given carrier . These RBs are selected from a contiguous subset of the common resource blocks for a given numerology (u). It is denoted by BWP. Each BWP defined for a numerology can have following three different parameters.28 Eyl 2018

Initial BWP is used to performs Initial Access Process . It includes Parameters like RMSI (Requested Minimum System Information), CORESET* and RMSI Frequency location/bandwidth/SCS. It can be 24~96 PRBs with different settings and relaxed to wider BWP after RMSI decoding.