# Optimal Meshing Degree Performance Analysis in a mmWave FWA 5G Network Deployment
## 1 Introduction  
Fifth-generation (5G) technologies have reached a stage where it is now feasible to consider operational deployments that extend beyond traditional Mobile Network Operators (MNOs). This allows for a range of new operators to enter the market or for public institutions and large enterprises to deploy bespoke 5G networks for their own purposes. Central to these affordances is the application of Fixed Wireless Access (FWA) in the context of 5G Non-public Networks (NPNs) that utilise a novel combination of radio technologies to meet their specific requirements. Moreover, as a result of many of these deployments occurring in areas where a traditional wired core is not feasible, such as in predominantly rural environments, wireless backhauling has become an important challenge with respect to operators' ability to provide multi-gigabit capacity while using cost-efficient technologies. High-capacity backhauling is also a key enabler for upcoming 6 th Generation (6G) technologies and will help handle the corresponding tremendous volumes of data to support the expected high-data-rate 6G user services [1]. Millimetre-wave (mmWave) technologies, including those operating in the V-band (60 GHz) and the E-band (70/80 GHz), have become a feasible enabler of this process, and backhaul links using these bands may be well suited to supporting 5G and 6G due to their high-throughput and low-latency characteristics [2]. Indeed, several such 5G deployments using these technologies have already taken place. Unfortunately, as a trade-off for reduced costs and relatively simple deployment, there are many challenges involved in the use of FWA backhaul, such as the potential need to contend with interference and carefully consider the physical environment in each case. One particular issue is the need for robustness in the backhaul core, as losses of connectivityare not unheard of, and error-prone connections are more commonplace. Specifically, the use of meshed deployments is critical in this context as it provides resilience against the temporary loss of links due to these errors [3]. However, as discussed above, a trade-off exists in terms of the deployment and operational costs of a fully meshed configuration vs. the need for coverage, performance, and resilience. In this paper, we examine the use of meshing in a mobile network backhaul deployment. To this end, we consider the use case of Fixed Wireless Access (FWA) backhaul in the context of 5G NPNs that utilise a novel combination of radio technologies to meet their specific requirements. While there has been some work on the evaluation of 5G performance [4], there are comparatively few studies on this topic [5] as 5G NPNs have only been deployed in limited numbers to date and this specific aspect of the backhaul has not been considered in a practical deployment scenario. Specifically, we discuss the trade-offs that exist between the need for more nodes/links to provide multiple paths to the nearest Point of Presence (POP) and, therefore, better resilience but also the higher cost of the network. Our aim is to determine the optimal degree of meshing that is needed for a specific backhaul network, i.e., a 5G FWA deployment, based on the deployment environment, networking requirements, and technologies used, and we will draw from a rich range of previous research in Wireless Meshed Networks (WMNs) and our own experiences to do so. We believe this work can significantly contribute to both the research community and those planning future 5G NPN deployments as more are deployed over time. The main novel contributions of this work can be summarised as follows:  
* The presentation of the quantifiable performance improvements to be gained when employing increasingly dense next-generation meshed backhaul networks;
* The delineation of the performance trade-offs that must be considered in such a 5G FWA meshed network in terms of throughput vs. stability. The remainder of the paper is structured as follows.