Throughput Efficient Dynamic Spectrum Sharing Between 4G-LTE and 5G-NR Using LTE CRS

Dynamic Spectrum Sharing (DSS) enables fourth-generation long-term evolution (4G-LTE) and fifth-generation new radio ($5 \mathrm{G}-\mathrm{NR}$) technologies to coexist within the same frequency bands, facilitating efficient spectrum utilization. This paper presents a novel approach leveraging cell-specific reference signals (CRS) 4G-LTE for 5G-NR channel measurements, which allows 5G-NR channel state information reference signals (CSIRS) for data transmission. By repurposing LTE CRS for NR measurements and utilizing NR CSI-RS resource elements (REs) for data transmission, the proposed method enhances the throughput of the NR network without compromising LTE operations. i.e., it does not demand any extra REs from LTE for NR data transmission. The simulation results demonstrate improvements in data throughput, validating the feasibility and benefits of the proposed approach over the traditional methods in which LTE and NR use separate reference signals for their measurements.