## 4 The Up/Down Mechanism of WiFi MAPs
### Algorithm Specification
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**ModelFaces**} & \multirow{2}{*}{**Without WiFi**} & \multicolumn{2}{c}{**Internal**} & \multicolumn{2}{c}{**WUSB600N**} & \multicolumn{2}{c}{**ALFA**} \\ \cline{3-8}  & & **Down** & **Up** & **Down** & **Up** & **Down** & **Up** \\ \hline RPI3 (node7) & - & 2.0 W & 2.7 W & - & - & - & - \\ RPI2 (node4, node1) & 2 W & - & - & 2.2 W & 3.9 W & 2.9 W & 4.3 W \\ RPI2+LCD (node6) & 3.4 W & - & - & 3.2W (5.9 W) * & 4.4 W (6.2 W) * & - & - \\ \hline \hline \end{tabular}

* includes monitor, keyboard and mouse extra average-power.

\end{table} 
Table 8: Average-power consumed in every configuration. Figure 26: Wattmeter used in our experiment. In our test platform, as Section 6.1 describes, we program node7 for both a single change to _IFACE_DOWN_s_ state at instant \(t\) = 10 and a dynamical change with different duty cycles for deactivation and activation. Specifically, assuming a repeating cycle of _MAP_ON_s_ for 4 s and _IFACE_DOWN_s_ for 2 s, node7 consumption drops to 149.4 W-min and global PWMNS consumption drops to 54.492 kWh. ## 7 Conclusions

In the last years WMNs have received close attention as an infrastructure for transporting traffic, being particularly noteworthy their role as sensing-data interconnection means throughout wide areas like smart cities. WMNs constitute a flexible solution which allows us to quickly deploy a backbone for sensing-data transport, across environments where alternative options (such as wired networks) are not appropriate. Furthermore, this deployment could be focused as a new concept, where sensors and end-users overlap with the backbone (WMN) thus shaping what we have called PWMNS, which allows a complete and portable solution for sensing data to be spread through the smart city. But this fast spread itself constitutes also an important problem, especially as regards average-power consumed by mesh nodes as well as harmonious coexistence with other wireless devices in the smart city. In this paper we have proposed a mechanism for redressing the interferences caused, not only by external devices to our PWMNS, but also in the opposite direction. Thus we contribute towards the concept of Wireless-Friendliness, which should logically guide an environment where more and more wireless devices arise. On the other hand, our proposal also imposes a logical rationalizing of the average-power consumed by the PWMNS nodes, not only in order to extend their operational cycle in case of portable deployment, but also for reducing their carbon footprint. Hence, our PWMNS will intend any of its routes selected for connecting sensors with end-users to be established through nodes subjected to the lowest possible interference and which increase the power saving as much as feasible. Other works could be integrated in our mechanism for increasing the power saving. For this reason we showed with experimental results that our work increases power saving with respect to other related works. We have sketched a concurrent set of routines which allows PWMNS nodes (along with a routing protocol as OLSR) to be coordinated for both redressing any experienced interference and increasing the power savings. Our simulation analysis has revealed that both targets may be simultaneously reachable. Although that simulation consisted of a straightforward 3 \(\times\) 3 mesh, it helped in clarifying the meaning of our developed measures of interference redress \(R^{Z}(t)\) and power saving \(S^{Z}(t)\). Larger meshes were not possible to be tested due to the complexity increasing of finding all possible paths. Anyway, in a future work we intend to study the behaviour of our measures when randomly chosen paths are selected by OLSR under the _Network Simulator_ (NS) environment. We have used a test platform based on four RPis (routed by means of OLSR) for testing our new strategy of setting the WiFi interfaces of MAPs down. We did some measures indoors considering four different cases of interference patterns.