## 3 WSAN System Models
### Modified AODV over IEEE 802.15.4 for Building Temperature Control
#### 4.2.3 Simulation Results  
The simulation results as in Tables 6 to 7 and Figures 10 to 11 show that the modified AODV routing as denoted by MA outperforms the original AODV routing for all response variables. At the \begin{table}
\begin{tabular}{p{142.3 pt}|p{142.3 pt}|p{142.3 pt}} \hline \multicolumn{3}{c|}{**Parameters**} \\ \hline Description & Notation & \\ \hline Threshold & \(T_{Threshold}\) & 8,840 \\ Average time required to propagate the RREQ message from the network layer to the MAC layer at a sender [43] & \(T_{Routing\_layer\_to\_MAC\_layer}\) & 5,000 \\ Average time required to propagate the RREQ message from the MAC layer at the sender to the MAC layer at the receiver [41, 42] & \(T_{MAC\_layerto\_MAC\_layer}\) & 3,840 \\ Average time required to propagate the RREQ message from the MAC layer at the receiver [41, 42] & \(T_{MAC\_layerto\_Routing\_layer}\) & - \\ Average time required to propagate the RREQ message from the MAC layer at the receiver [41, 42] & \(T_{BO}\) & 1,120 \\ Average time required to propagate the RREQ message from the MAC layer at the receiver [41, 42] & \(T_{BOSlot}\) & 128 \\ Average time required to propagate the RREQ message from the MAC layer at the receiver [41, 42] & \(T_{BOSlot}\) & 1,952 \\ Average time required to propagate the RREQ message from the MAC layer to the network layer at a receiver & \(T_{BOSlot}\) & 3.5 \\ Average back off time & \(T_{BOSlot}\) & 320 \\ Clear channel assessment time & \(T_{CCA}\) & 61 bytes \\ Transmission time for the RREQ message & \(T_{frame}\) & 61 bytes \\ Inter frame spacing (IFS) time & \(T_{IFS}\) & 250 kbps \\ Number of back off slots & \(BOSlot\) & 250 kbps \\ Time for a back off slot & \(T_{BOSlot}\) & 250 kbps \\ RREQ packet size (including Synchronization and PHY headers) & \(RREQ_{PacketSize}\) & 61 bytes \\ Data rate & \(Data\_Rate\) & 250 kbps \\ \hline \multicolumn{3}{p{142.3 pt}}{_Note: \(T_{Routing\_layer\_to\_MAC\_layer}\) and \(T_{BO}\) are set to mean values. \(T_{IFS}\) is the long-frame spacing time in our case._} \\ \multicolumn{3}{p{142.3 pt}}{Long IFS is used when the packet size is greater than 18 bytes [41, 42].} \\ \end{tabular}
\end{table} 
Table 5: Parameters used for the threshold calculation. CBR rates from 0 to 2 Mbps, the number of data packets successfully received by the sink is getting increased. The settling time is improved, like the case of no CBR background traffic interruption. Additionally, the total energy consumption of nodes is largely decreased. Note that both communication and control performance results are most improved at the CBR rate of 2.0 Mbps. The reason why the proposed solution gives the better results than the AODV is discussed here. According to the proposed algorithm, all nodes in the network avoid to transmit the RREQ message to the path with congestion. Thus, the path with the lower traffic load/ or satisfied the predefined threshold condition is often selected. Delivering routing and data messages along the path with a low traffic load can reduce the possibility of the packet loss and the failure of route establishment process. These can help to improve both the desired control objective and the network performances. For the CBR rates from 2.5 to 3.25 Mbps, the simulation results for all performance metrics are the same as using the original AODV routing protocol. This is because the nature of this network scenario at higher CBR rates and the effect of a buffer overflow influence our proposed solution, like the case of using the AODV routing protocol. Figure 11 demonstrates that the total energy consumption at each interval of time is reduced when the route changes to the path with a lower traffic load. At the CBR rates from 0.75 to 2.00 Mbps as in Figure 11(a-c), the total energy consumption is getting decreased at time intervals after 2,375 s, 1,625 s, 1,125 s, 1,125 s, 885 s and 885 s, respectively. On increasing of CBR rates, the upper path is fast chosen in comparison with using the original AODV.