Dynamic Spectrum Sharing (DSS)facilitates Communication Service Providers (CPSs) to utilise their spectrums and hardware resources dynamically in both LTE 4G and in 5G, in the both time and frequency domains as Shown in fig 1. Implementation of DSS idea need to study in details frame structures, control, synchronizations and traffic channels of 4G-LTE and 5G-NR.The physical layer of 5G designed as 4G of 3GPP where DSS is feasible and has equal subcarrier spacing of time domain. DSS design is backward compatible of all LTE equipment. Telecom service providers (TSPs) thus want to maintain reference signal of LTE cell reference of signal (CSR) transmission. Design of 5G transmission hardware keep similar to LTE CSR, it is called CSR matching of rate. In 5G Demodulation Reference Signal (DMRS), along with Phase tracking Reference Signal (PTRs),Sounding Reference Signal (SRS) and Channel State Information Reference Signal (CSI-RS) is used. And in LTE-4G Transmission Mode (TM 09) is used to overcome interference between base stations (NodeB) and to maximise signal stability and to improve performance.

Dynamic Spectrum Sharing (DSS), Long Term Evolution (LTE), Cell Reference Signal (CRS), 4G, 5G, New Radio (NR), 3GPP.