The Cross-Carrier Scheduling in LTE-NR Dynamic Spectrum Sharing

The LTE-NR Dynamic Spectrum Sharing (DSS) mechanism can dynamically allocate spectrum resources for LTE and 5G users according to traffic requirements, which can realize smooth evolution from 4G to 5G. Since LTE and NR share control channel resources on the shared spectrum, the resource which can be used for NR downlink control channel is limited. To cope with this, the Cross Carrier Scheduling (CCS) from Secondary Cell (SCell) to Primary Cell (PCell) has been considered as a solution. However, the CCS from SCell to PCell will bring great challenges in some aspects, such as the PDCCH blind decoding for UE. In this paper, the problem caused by SCell scheduling PCell and the impact on the communication specification design are introduced and analyzed. In addition, several technical solutions are presented. The analysis shows that these technical solutions can effectively solve the PDCCH blind decoding problem caused by CCS from SCell to PCell, which has great reference value for operator to deploy LTE-NR dynamic spectrum sharing.