, unlike LTE, the NR system is also prepared for future technology evolution. In particular, co-existence of NR system transmissions to UEs from different releases can be performed through the use of a feature termed special "blank resources" (rate-matching resources). Blank resources can be flexibly configured for UEs of a previous 5G NR release (not supporting the new functionality of the latest NR release) in time and frequency, thus avoiding overlap between the transmissions to UEs from different releases. Power efficiency: To reduce power consumption, NR system avoids "always on" trans- missions, for example, reference signals such as the cell-specific reference signal (CRS) used in LTE. Instead, demodulation of the physical channels in NR mainly relies on user-specific DM-RS. Moreover, for better power consumption efficiency at the UE, the bandwidth of the physical channels used by a UE can be adapted through the config- uration of a new NR feature called bandwidth part (BWP). BWP allows the allocation of smaller bandwidths to a UE to reduce its power consumption or wide bandwidths to support very high data rates. New Channel Coding: NR supports new types of channel coding based on Low-Density Parity Check (LDPC) and Polar coding, which are used for the data and control channels, respectively. The key advantages of LDPC (compared with convolution turbo coding used in LTE-A) are improved performance with very low error floors, reduced decoding com- plexity and latency, better power and area efficiency, and support of multi-Gbps data rates. Polar coding yields better performance compared with the convolutional codes supported in LTE for control channel transmission. In the present chapter we describe the NR physical layer, focusing on differences com- pared with LTE. 3.5.2 Waveform and Numerology Unlike LTE, which supports different waveforms for downlink and uplink, Release-15 NR adopts the cyclic prefix (CP)-OFDM waveform for both downlink and uplink (3GPP TS 3.5 NR Physical Layer Table 3.5.1 Scalable numer