## 1 Introduction
Specifically, the main issues during a LoRaWAN network design process that we identify as not properly addressed by the literature concerning the aforementioned performance trade-off could be summarized as follows:  
* Estimation of the number of GWs we need to setup to cover are required network capacity within a rural area of specific size. Simultaneously, estimation of the number of EDs that can be optimally supported by a network depending on their communication parameters [9; 11; 13; 22; 23]. * Identification of the performance failures that are due to configurable parameters of LoRaWAN communication [8; 13]. * Simulation-based performance evaluation depending on several scalability-related metrics such as energy consumption, PDR, throughput, coverage, and latency [19]. Through an experimental assessment we will, then, evaluate the correlation of variables such as spreading factors, GW deployment, duty cycle, transmission and interference parameters. With such experiments we attempt not only to analyze the trade-off triangle of coverage, scalability and energy efficacy, but also to dive deeper to the crucial factors that affect these communication performance indices. The result of this study is a set of guidelines towards the optimal configuration of a LoRaWAN network and the clustering of end nodes in the vicinity of a gateway, taking into account distance and transmission settings, that can improve network scalability. Appropriate simulations assess the validity of these guidelines. Contributions of our work include:  
* Summarization of the crucial factors, as mentioned in literature, that affect communication performance of LoRaWAN networks. * Experimental assessment of the aforementioned factors, based on insights from the literature, regarding the communication performance alterations they can cause. * Cross-evaluation experiments that take into consideration the causalities of performance observations and the factors that affect them. * Generation of a layered-based configuration logic, in terms of network planning guidelines, that takes into account application constraints and QoS requirements. The goal of this work is to improve the deployment of large LoRaWAN networks by enhancing arguments for causal relationships among factors that usually are bypassed during the network design stage and contribute further the research on easy-to-use models that are required [24] to plan and assess the deployment of LoRaWAN networks. This is the challenge we aim to approach in our further studies. The structure of the paper is organized as follows: In Section 2 we review in detail how key mechanisms and concepts of LoRa technology work and how they affect the performance of such a network. Additionally, we identify and analyze the causal relationships between factors that affect performance of the network, we summarize the challenges that a LoRaWAN network needs to overcome in suburban and rural deployments, as well as the necessary metrics for argument on the following findings. Furthermore, we describe the research methodology we are going to follow, including the variables that we will control and observe, and also the experimental setup for making the corresponding measurements. In Section 3, with our controlled experiments, we contribute some new insights on coverage, scalability and energy consumption of LoRaWAN networks, which are the most important parameters for the protocol adoption. Finally, in Section 4 we discuss our findings and give our guidelines for facilitating network deployment. This proposition aims to make factor-centric observations in relation to communication performance challenges. Our approach bypasses some basic LoRaWAN concepts that network deployers are already aware of, and concentrates directly on key aspects of the technology.