# Experimental Performance Analysis of Wi-SUN Channel Modelling Applied to Smart Grid Applications
## 5 Measurement Setup  
In Thailand [19], frequency bands and PHY layers of the Wi-SUN network for the AMI smart grid application are not specified yet; however, NBTC has provided three unlicensed bands (i.e., 433 MHz, 920-925 MHz and 2.4 GHz) and two licensed bands to be jointly used for smart grid applications. As guided from Table 2 and [7], a table of data rates and frequency bands of the 2 FSK PHY layer of the Wi-SUN network in Thailand is proposed in this article. Table 1 is used in the experiment to model the Wi-SUN channel correspondingly in many different data rates and frequency bands. The frequency bands and transmit power with antenna gain, expressed in Table 1, have followed the regulation set by NBTC [19]. The IEEE 802.15.4g network was set up for the channel RSSI measurement in the residential area on the outskirts of Nonthuburi Province, Thailand. This area represents the tropical residential housing on developed real estate, in which each house has the same pattern and alignment across the main street. However, the big tree nearby the street was the obstacle for the transmitter and receiver installed on the utility's low-voltage pole. The atmosphere of the experimental area is shown in Figure 3. This article will specifically focus on the residential customers of MEA and PEA, i.e., Thai electricity utility companies. The Tx and Rx for realizing the Wi-SUN communication based on the IEEE 802.15.4g standard in this article are LAUNCHXL-CC1352P from Texas Instruments, which is a programmable development board supporting the IEEE 802.15.4g network for collecting measured values in computers, as shown in Figure 4. The experimenting IEEE 802.15.4g transmitter was installed four meters high on a tripod, which was used to simulate the DCU position on a utility's low-voltage pole located along the side of the street. The transmitter packet was 255 bytes periodically sent every 500 ms in all aliases without FEC, as shown in  
Figure 3: The experimental residential area. Figure 2: BER of the 2 FSK Wi-SUN channel with various data rates (50, 100, 150, 200 kbps). The received signal strength distribution was typically approximated by a Rician distribution curve fitting, which was a conventional Rician distribution approximation. For the improved accuracy of distribution approximation, the biased Rician distribution approximation was applied to the measured RSSI distribution, in which it was biased by a bias function \(w(r)\) in Equation (8) before being approximated by the Rician distribution. The \(r_{s}\) and \(\sigma\) parameters are derived for both conventional and biased Rician distribution curve fittings. The K-factor was calculated by substituting \(r_{s}\) and \(\sigma\) into Equations (2) and (3). Root mean-squared error (RMSE) was used to evaluate an error between the Rician distribution approximation and the measured RSSI distribution. The K-factor, \(r_{s}\), \(\sigma\) and RMSE parameters of conventional and biased Rician distribution curve fitting are shown in Tables 4 and 5, respectively. CDF and PDF of conventional and biased Rician distribution curve fitting were applied to the RSSI measurement data taken from the experimental environment in all aliases (Table 1). For example, the conventional and biased Rician distribution curve fitting of 2 FSK-433-50 alias was a PHY layer of the IEEE 802.15.4g channel, in which the 2 FSK modulation 433.92 MHz multi-data rates (50 kbps, 100 kbps and 200 kbps) was fitted, as shown in Figures 7-9, respectively. The Rician distribution estimation of RSSI for 2 FSK 433.92 MHz Wi-SUN channel approximation with multi-data rates (50 kbps, 100 kbps and 200 kbps) is presented in Figure 10.  
Figure 8: (**a**) CDF and (**b**) PDF of conventional and biased Wi-SUN channel approximation (2 PSK-433-100 alias). Figure 10: (**a**) CDF and (**b**) PDF of biased 2 FSK 433.92 MHz multi-data rates Wi-SUN channel approximation (50, 100, 200 kbps). Figure 9: (**a**) CDF and (**b**) PDF of conventional and biased Wi-SUN channel approximation (2 PSK-433-200 alias).