# Optimized DM-RS Configuration for Improved 5G New Radio Network Capacity and Performance.
## 6 Discussion and Conclusions  
As 5G networks become more mature and new use cases are being introduced, first network congestions may be observed in some markets, and there is an evident trend of moving focus from securing coverage to ensuring sufficient capacity. 5G systems were designed as ultra-lean, and always-on signals were minimized. Still, further optimization and additional margins of capacity and performance that may be unleashed through overhead reduction are more than welcome. In this paper, potential gains that may be achieved through DM-RS optimization were considered, starting from a technical background and a deep dive into Doppler shift phenomena, through feasible proposals for configuration optimization that will not affect performance, to testing on commercial networks and live traffic and verification of results. An overview of achieved improvements in domains of spectral efficiency, network capacity, user-experienced throughput and resource allocation or utilization is presented in Table 2.  
The main outcome of the research is findings that the initial configuration settings proposed by RAN vendors seem to be quite conservative, especially for the common deployments today, where a 3.5 GHz frequency band is used with standardly implemented SCS of 30 kHz and the speed of users does not exceed 120 km/h. As per the outcome of  
Figure 12: Link adaptation performance comparison before/after: (**a**) modulation distribution—QPSK vs. 16 QAM vs. 64 QAM vs. 256 QAM; (**b**) block error rate (BLER). Figure 13: PRB allocation improvement due to better spectral efficiency, comparison before/after: (**a**) primary cell—Fc = 3.5 GHz; (**b**) secondary cell—Fc = 3.4 GHz. the research presented in this paper, there is significant room for capacity improvement to be achieved through DM-RS reconfiguration and parameter optimization. The set of observed key performance indicators depended on the deployed use case and analysis methodology, but in general, improvements were verified in the range of 5-15% depending on the network specifics, such as traffic mix, spectrum assets, network load, topology and deployment strategy. With increasing demands for 5G/NR capacity, operators will search for network improvements in different areas, from network deployment strategy revisions, system reconfiguration and optimization to the deployment of additional capacity that may be achieved through the implementation of even more advanced antenna solutions or network topology densification. The proposed capacity improvement methodology does not conflict with other methods, and the implementation of this method is very efficient with minimal related costs. The next steps in research are to extend the analysis and cover use cases for faster-moving terminals, and to explore possibilities for automatic detection of the presence of users with very high speeds and dynamic adjustments of the DM-RS configuration accordingly. Conceptualization, I.T., D.D. and P.I. ; data curation, I.T., U.S., D.T. and A.L. ; formal analysis, I.T., U.S., D.T. and A.L. ; investigation, I.T. and U.S.; methodology, I.T. and D.T. ; project administration, I.T. ; software, I.T., U.S. and D.T. ; supervision, I.T., D.D. and P.I. ; validation, I.T. ; visualization, I.T. ; writing--original draft, I.T. ; writing--review and editing, I.T., D.D. and P.I. All authors have read and agreed to the published version of the manuscript. This research received no external funding. The data presented in this study are available on request from the corresponding author. The data are not publicly available due to confidentiality issues and may be provided only with prior approval from data owners, which are mobile operators that Aspire Technology supports. However, as PM systems and counters are quite unified, similar data can be fetched from any other mobile operator where DM-RS optimization is executed. The authors would like to express gratitude to NEC Aspire Technology for various types of support during the project.