## 3 Wireless Sensor System Deployment  
### Radio Planning  
Once the simulation tool has been validated and prior to the deployment of the WSN within the workshop, a brief 3D-RL-based radio planning study has been performed to gain insight regarding the feasibility of deploying the desired and proposed ZigBee-based WSN within the curtain factory workshop. The simulation parameters are the same as those presented in the previous section. The aim of this analysis is to help understand the radio propagation behavior and the connectivity limitations within the workshop. First, the PDPs (power delay profile) depicted in Figure 7 show the propagation complexity of the scenario under analysis. These estimated time domain results provide a clear view of the multipath propagation complexity at each point within the scenario. Four different locations are presented in the figure as examples, corresponding to the measurement points 3, 10, 13, and 15 (at a height of 1.3 m) presented in Figure 4a. Transmitter 1 results correspond to transmitter locations shown in scenario 1 (Figure 4a), and Transmitter 2 results correspond to scenario 2 (Figure 4b). It has to be mentioned that multipath components with less than \(-100\) dBm are not presented in the graphs, since this is the sensitivity level of the ZigBee motes employed in this work. As expected, the environment is very rich in terms of multipath propagation due to the presence of several metallic scatterers and different objects, typical in industrial environments. Moreover, in this case, the LoS and NLoS conditions could have a significant effect on the wireless link performance. In order to analyze the feasibility of the deployment of ZigBee wireless nodes and the quality of the wireless link between them, RF power distribution results have been obtained. These results have been obtained for the whole 3D volume of the workshop for both scenario 1 and scenario 2. Obtaining results for the whole volume of a scenario leads to a complete radio planning analysis since the radio links can be analyzed even if the transmitters and receivers are deployed at different heights, where the RF power distribution will vary. As an example, Figure 8 shows the RF power level distribution for three different heights (i.e., 1 m, 2 m, and 3 m from the floor) for scenario 2. Note that the transmitter (Tx in the figure) is located at height = 1.3, but the black dots representing it are drawn in every map for a better understanding of the setup. It can be noted that, when the height is increased, the shadowing effects due to obstacles (mainly machinery) tend to disappear, since the machinery distributed throughout the workshop presents an overall height of 1.2 m.  
Figure 6: Measurements vs. 3D-RL simulation results for (**a**) scenario 1 and (**b**) scenario 2. Returning to the cases under analysis, Figure 9 shows the obtained estimations for both scenario 1 and scenario 2. Specifically, 2D planes at a height of 1.3 m are presented, where the main RF power drops are caused by shadowing effects and NLoS situations due to walls and machinery. In this way, it can be seen how the detected RF power in some areas falls near and under the \(-100\) dBm sensitivity threshold of ZigBee motes (dark blue points in the coverage map). This means that in some specific cases, the wireless  
Figure 8: The diagram shows 2.4 GHz RF power level distribution maps at different heights for scenario 2. Figure 7: Estimated power delay profiles at different locations (measurement points) for both TX1 and TX2 (a) location 3; (b) location 10; (c) location 13; (d) location 15.  
communication between two ZigBee motes deployed within the scenario could fail. In order to gain insight into this matter, Figure 10 shows the areas where the RF power level is higher (green zones) and lower (red zones) than the sensitivity level of the motes. As can be seen, most of the planes' areas are green, which means that receivers deployed there will comply with the required sensitivity level for the simulated specific Tx locations.