CDM group are quasi-co-located with respect to Doppler shift, Doppler spread, average delay, delay spread, and spatial RX parameters. Note that the spa- tial RX parameters are meant to describe angular/spatial channel properties at the UE to help the UE select and use one of the beams. The UE can use SS/PBCH block to obtain fre- quency offset, timing offset, Doppler spread, delay spread, and receive beam to process DM-RS. In other words, one can consider the spatial RX parameters as beam indication for the UE, where UE may use the acquired channel parameters from SS/PBCH to receive PDSCH. 4.1.2.2 Phase Tracking Reference Signals The PT-RS was introduced in NR to enable compensation of oscillator phase noise in above-6 GHz frequency bands. Phase noise typically increases as a function of carrier fre- quency. Therefore, PT-RS can be utilized at high carrier frequencies (e.g., mmWave bands) to mitigate the phase noise effect. In the case of OFDM signals, the effect of phase noise is identical phase rotation of all the subcarriers, known as CPE. In NR, the PT-RS is designed To explain the spatial RX concept, let's consider receive antenna diversity where the transmitted signal is received by N antennas which are assumed to have sufficient spatial separation resulting in independent mul- tipath channels between the transmitter and each receiver antenna. Denoting the channel vector, including the amplitude and phase coefficients representing the aggregated effects of multipath propagation, by h = (h1, h2, hn) E CNX1, the received baseband equivalent signal vector reCNX1 can be expressed + n Consequently, by combining the signals from the separate antenna branches with a proper weight- ing, we obtain the combiner output being equal to YRX = WHr = WHh + WH n, where WeCNX1 denotes the weighting vector of the combiner. It is important to note that now the steering vector is replaced with a more generic channel response, including arbitrary amplitude and phase response for each antenna branch. Consequently, the combiner wei