# Optimal Meshing Degree Performance Analysis in a mmWave FWA 5G Network Deployment
## 6 Conclusions  
In this paper we have explored the optimal degree of meshing in FWA meshed network backhauls as analysed via the Liverpool 5G deployment. The specific context of this network involves a core made up of 60 Ghz 802.11 ad links deployed in a street canyon model approximately 80-100 m in length. We have examined the existing literature on this type of deployment and in the broader context of WMNs and found that it most closely conforms to a static deployment, which benefits most from a simplistic, exact optimisation approach. We also highlighted the need for resilience and meshing in this context.  
Based on this, we considered a specific sub-network of the Liverpool 5G deployment, which is currently composed of a single available path to a POP for most nodes. Thus, we then introduced two further extensions to this physical deployment, which benefit from incrementally denser meshing for the nodes and links. We then simulated the performance of each topology using realistic link characteristics and a simple shortest path routing protocol in an attempt to determine the optimal degree of connectedness.  
Our results show that increasing the meshing degree in the network brings minor incremental improvements in overall network latency but limited improvements in stability. There are also substantial potential gains in terms of throughput and data rate, but these come at the expense of increased volatility. The improvements in terms of the Packet Delivery Fraction (PDF) were largely inconclusive but showed some improvements from greater meshing. However, the results regarding Packet Error Rate (PER) did not show a significant improvement across the three topologies, and there was a large amount of variation in the results we obtained for this metric. Thus, the quantification of the performance improvement is not straightforward in this case, and a trade-off is clearly needed between outright network throughput and stability. Nevertheless, a clear improvement over the unmeshed topology was delivered in each case.  
This research offers a number of useful insights in both research and practical contexts. The real-world analysis of 5G NPN FWA deployments provides useful insights into new types of mmWave network optimisation, which can fuel the planning and development of Beyond 5G and 6G technologies. Moreover, our results can immediately be fed back to new network operators who are planning 5G NPN deployments in order to help them optimize their backhaul network in terms of the trade-off of cost vs. performance. This has already been performed in the context of Liverpool 5G, and our results have been disseminated back into the UK5G community and beyond.  
Our next steps in this area include further analysis of our results to fine-tune the performance improvements identified and then the consideration of more sophisticated multi-path routing algorithms to further improve the advantages offered by meshing. In addition, we will further quantify these gains against the cost of denser deployments using a Return on Investment (ROI) calculation to understand this trade-off in more detail.  
Conceptualisation, M.M. and A.R.; methodology, M.M., A.R. and I.G.; software, A.R. and I.G.; validation, I.G. and A.R.; formal analysis, I.G. and A.R.; investigation, M.M. and A.R.; writing--original draft preparation, A.R., M.M. and I.G.; writing--review and editing, M.M. and A.R.; visualisation, I.G.; supervision, A.R. and M.M. All authors have read and agreed to the published version of the manuscript.  
This research was partly funded through the UK DCMS Liverpool 5G Create project ([[https://uk5g.org/discover/5G-projects/testbeds-and-trials/liverpool-5g-create/](https://uk5g.org/discover/5G-projects/testbeds-and-trials/liverpool-5g-create/)]([https://uk5g.org/discover/5G-projects/testbeds-and-trials/liverpool-5g-create/](https://uk5g.org/discover/5G-projects/testbeds-and-trials/liverpool-5g-create/)), accessed on 14 June 2023).  
Not applicable, the study does not report any data.  
The authors declare no conflict of interest.