Default QCL Assumption for PDSCH Reception

#The disclosed embodiments relate generally to wireless network communications, and, more particularly, to Physical Downlink Shared Channel (PDSCH) reception in 5G new radio (NR) wireless communications systems.

#Third generation partnership project (3GPP) and Long-Term Evolution (LTE) mobile telecommunication systems provide high data rate, lower latency and improved system performances. In 3GPP LTE networks, an evolved universal terrestrial radio access network (E-UTRAN) includes a plurality of base stations, e.g., evolved Node-Bs (eNBs) communicating with a plurality of mobile stations referred as user equipment (UEs). Orthogonal Frequency Division Multiple Access (OFDMA) has been selected for LTE downlink (DL) radio access scheme due to its robustness to multipath fading, higher spectral efficiency, and bandwidth scalability. Multiple access in the downlink is achieved by assigning different sub-bands (i.e., groups of subcarriers, denoted as resource blocks (RBs)) of the system bandwidth to individual users based on their existing channel condition.

#The bandwidth shortage increasingly experienced by mobile carriers has motivated the exploration of the underutilized Millimeter Wave (mmWave) frequency spectrum around 30G and 300G Hz for the next generation 5G broadband cellular communication networks. The available spectrum of mmWave band is two hundred times greater than the conventional cellular system. The mmWave wireless network uses directional communications with narrow beams and can support multi-gigabit data rate. 5G new radio (NR) beamforming wireless systems support UEs operating with single wideband carrier and UEs operating with intra-band carrier aggregation over the same contiguous spectrum simultaneously.

#FIG. 1 illustrates a wireless communications system supporting default Quasi-Co-Location (QCL) assumption for Physical Downlink Shared Channel (PDSCH) reception in accordance with a novel aspect.

#FIG. 2 is a simplified block diagram of a wireless transmitting device and a receiving device in accordance with a novel aspect.

#FIG. 3 illustrates the relationship between PDSCH scheduling offset and a time duration for QCL for PDSCH reception in a wireless communication system.

#Reference will now be made in detail to some embodiments of the invention, examples of which are illustrated in the accompanying drawings.

#FIG. 1 illustrates a 5G new radio (NR) wireless communications system 100 supporting default Quasi-Co-Location (QCL) assumption for Physical Downlink Shared Channel (PDSCH) reception in accordance with a novel aspect. 5G NR mobile communication network 100 comprises a base station BS (or gNodeB) 101 and a user equipment UE 102. In the example of FIG. 1, BS 101 is directionally configured with multiple serving cells, and each serving cell is covered by a set of coarse TX/RX control beams. For example, serving cell 110 is covered by a set of eight downlink (DL) control beams CB1 to CB8. The collection of the DL beams CB1-CB8 covers an entire service area of cell 110. Similarly, UE 102 may also apply beamforming to form multiple UE beams, e.g., #U1-#U8. Each DL beam transmits a set of known reference signals for the purpose of initial time-frequency synchronization, identification of the control beam that transmits the reference signals, and measurement of radio channel quality for the control beam that transmits the reference signals. In NR systems, each of the DL beams are used to transmit a corresponding system synchronization block (SSB) or a corresponding channel state information reference signal (CSI-RS).

#When there is a downlink packet to be sent from gNodeB to UE, each UE gets a downlink assignment, e.g., a set of radio resources in a physical downlink shared channel (PDSCH). When a UE needs to send a packet to eNodeB in the uplink, the UE gets a grant from the eNodeB that assigns a physical uplink shared channel (PUSCH) consisting of a set of uplink radio resources. The UE gets the downlink or uplink scheduling information from a physical downlink control channel (PDCCH) that is targeted specifically to that UE. In addition, broadcast control information is also sent in PDCCH to all UEs in a cell. The downlink or uplink scheduling information and the broadcast control information, carried by PDCCH, is referred to as downlink control information (DCI). The uplink control information (UCI) including HARQ ACK/NACK, CQI, MIMO feedback, scheduling requests is carried by a physical uplink control channel (PUCCH) or PUSCH if the UE has data or RRC signaling.