# On the Realistic Radio and Network Planning of IoT Sensor Networks
## 6 Result Analysis
### Packet Delivery  
This section analyses packet delivery, which represents a core performance parameter at the network layer. Tables 5-7 depict the simulated packet delivery values as retrieved from Cooja, when the two built-in propagation models of Cooja and the 3D polarimetric ray tracing model of TruNET wireless are utilized. The tables show the expected retrieved number of packets from each node to all others. Obviously, in order to achieve the optimum packet delivery, a strong communication link is required, i.e., a strong RSS value. The 3D ray racing algorithm of TruNET wireless produces a much more realistic estimate of the RSS coverage, indicating significant difference of packet delivery when compared with the other models. Analysis of results' differences are much more easily spotted in Figures 10 and 11. The most important observations are the following: (a) the packet exchange of Node 3 to Node 4, as well \begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline \multirow{2}{*}{**MRM**} & \multirow{2}{*}{\begin{tabular}{c} **Tx** \\ **(Packets)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Node 1** \\ **Rx** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Node 2** \\ **Rx** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Node 3** \\ **Rx** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Node 4** \\ **Rx** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Node 5** \\ **Rx** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Total** \\ **Rx** \\ \end{tabular} } \\ \hline
**Node 1** & 25,471 & - & 9576 & 13,030 & 0 & 0 & \\ \hline
**Node 2** & 24,989 & 18,663 & - & 20,184 & 19,117 & 0 & \\ \hline
**Node 3** & 25,398 & 13,821 & 18,948 & - & 0 & 0 & \\ \hline
**Node 4** & 25,269 & 0 & 17,422 & 0 & - & 24,428 & \\ \hline
**Node 5** & 25,343 & 0 & 0 & 0 & 24,266 & - & \\ \hline
**Total:** & 126,470 & 32,484 & 45,946 & 33,214 & 43,383 & 24,428 & 179,455 \\ \hline \multicolumn{7}{l}{Running Time: 10 min} & Tx Rate: 210,783 packets/s \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Packet delivery: Cooja MRM model. Figure 9: Measured RSS fluctuation of sensors (**a**) Indoor; (**b**) Outdoor. as Node 1 to Node 4, are only predicted by the combined usage of TruNET and Cooja simulators. These communication links are verified by the actual RSS measurements where we recorded RSS values between \(-79.9\) dBm to \(-81.4\) dBm, and they have been recorded. If this RSS value range is compared with results of Figure 2, it is obvious that network packets will be exchanged. (b) Node 3 and Node 2 are not expected to exchange any packets since they fail to establish a communication link (RSS values under the receiver threshold). However, MRM and UDMG models estimate a strong packet exchange. (c) Finally, the combined TrunNET-Cooja OSI cross layer expects that packet delivery between Node 3 and Node 5 will be problematic and packets will be lost, while the other two models expect an almost perfect packet delivery. Analysis of results indicates the problem that may arise when the wireless network design is based only on the output of a typical network level simulator, where the radio propagation models are not adequate to simulate complex suburban and urban outdoor and indoor scenarios. Models like MRM and UDMG consider that the transmission range is the range in which the transmitted packet can be received correctly by any node within this range, while the interference range is the range in which the transmission can be heard but the transmitted packet cannot be received correctly. Outside of these two ranges, packets can not be heard. Transmission and reception ratios are random variables that are added to the transmission or reception ratio of a packet to allow the simulation of random errors in the transmission or reception, respectively. Furthermore, a collision will be sensed only in the case that a node attempts to transmit, within the transmission or interference range of a node that is transmitting simultaneously.