 enumerated from 0 to VRB BWP(i) 1. The virtual resource blocks are resource blocks that are permuted across frequency dimension to take advantage of frequency diversity [12,28]. An interleaved mapping maps virtual resource blocks to physical resource blocks using an interleaver that spans the entire BWP and operates on pairs or quad- ruplets of resource blocks. A block interleaver with two rows is used, with pairs/quadruplets of resource blocks written in columns and read in rows. Whether to use pairs or quadruplets of resource blocks in the interleaving operation is configurable by higher layer signaling. The interleaved resource-block mapping in the frequency domain provides frequency diversity [13-15]. 3.7.2 Bandwidth Part 3GPP NR supports very large operating bandwidths relative to the previous generations of 3GPP standards. Since the UEs in a cell may have different bandwidth capabilities, the use Chapter 3 Carrier bandwidth Carrier bandwidth BWP 2 BWP 1 Supporting UE reduced bandwidth capability Supporting different numerologies in different BWPs carrier bandwidth carrier bandwidth Different BWP 2 BWP 1 Supporting noncontiguous spectrum Supporting UE reduced power consumption Carrier bandwidth Future Legacy technology technology BWP 2 BWP 1 Supporting forward compatibility Figure 3.49 Bandwidth part use cases [42]. of wide bandwidth may cause more power consumption and may increase RF and baseband implementation complexity. Therefore, NR introduces the concept of BWP and allows the UEs with different bandwidth capabilities to operate in the cell with (configurable) smaller instantaneous bandwidth relative to the configured cell bandwidth, making NR more energy efficient solution despite its support of wideband channels (see Fig. 3.49). Alternatively, one may consider scheduling a UE such that it only transmits or receives within a certain fre- quency band. However, the difference of the latter approach with BWP is that the UE is not required to transmit or receive outside of the configured frequency band o