# Context-Based Dynamic Meshed Backhaul Construction for 5G Heterogeneous Networks
## 2 Traffic Adaptive Dynamic Meshed Backhaul Construction For Outdoor Dynamic Crowd
### Numerical Results  
This section presents numerical analysis results of the proposed traffic adaptive construction of mmWave meshed backhaul. In our simulation, we deployed several macro cells with inter-site distance (ISD) of 500 m in the 4 square kilometer areas depicted in Figure 1. Only one macro cell at the center is selected for evaluation and the other surrounding ones work as LTE interference sources. Simulation parameters are summarized in Table 1.  
Examples of the formed mmWave meshed networks are shown in Figure 7. As there are few users in the evaluation area at 3 AM, only a few mmWave SC-BSs are activated. In this case, since there are enough resource blocks in the LTE, most of the users are connected to the macro BS, while users with very high traffic demand at the right-bottom activate SC-BSs. On the other hand at 3 PM, a hotspot appears in the upper-left zone. We can see some backhaul links formed from gateway to the hotspot, showing the effectiveness of the proposed traffic adaptive construction of mmWave meshed backhaul against the locally intensive traffic.  
This effect is evaluated quantitatively by an indicator called satisfaction ratio. It is defined as the portion of demanded traffic is completely delivered to UEs through the mesh networks. In our evaluation, we considered three mechanisms for decision of ON/OFF status of SC-BSs. The proposed approach in this paper is called \"Network centric ON\". For comparison, \"User centric ON\" scheme deactivates a SC-BS if and only if there is no UEs within its vicinity. It means that even if there is only one UE selects the AP as the anchored SC-BS, it will not be deactivated. The other comparison scheme is called \"Always ON\", which literally activates all SC-BSs permanently. Our evaluation result shows that all the three schemes can successfully deliver all demanded traffic towards UEs. In other words, our proposed \"Network centric ON\" scheme is equivalent to the other conventional schemes in terms of network capacity, regardless of many deactivated SC-BSs. It is owing to the capability of route multiplexing of the proposed scheme especially against intensive traffic time. Therefore, without sacrificing network performance, the proposed scheme is more energy-efficient than the other comparison schemes.  
The analysis of power consumption is shown in Figure 8. The figure shows the performance of total power consumption against dynamic traffic variation throughout a day. The power consumption includes both of the access and backhaul, which is defined as \(\sum_{i}^{N_{\text{S}}}(N_{i}^{\text{on}}P_{\text{on}}+N_{i}^{\text{off}}P_{ \text{off}})\), where \(N_{i}^{\text{on}}\) and \(N_{i}^{\text{off}}\) represent the number of ON sectors and that of OFF sectors of the \(i^{\text{th}}\) mmWave SC-BS respectively. From the figure, the effectiveness of the traffic and energy management algorithm is obvious especially in midnight. Roughly speaking, the proposed scheme reduces the energy consumption by a factor of half.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **LTE** & **mmW SC-BS** \\ \hline Carrier freq. & 2 GHz & 60 GHz \\ Bandwidth & 10 MHz & \(2\times 2.16\) GHz \\ Antenna height & 25 m & 4 m/25 m (SC-BS/GW) \\ Antenna gain & 17 dBi & 26 dBi \\ Tx power & 46 dBm & 10 dBm \\ Path loss & 3 GPP & [5] \\ Beam pattern & 3 GPP & 802.11 ad \\ No. of BSs & 1 & 90 \\ Noise level & & 174 dBm/Hz \\ \hline \hline \end{tabular}
\end{table}
Table 1: Simulation parameters.  
Figure 8: Numerical performance of total energy consumption.  
Figure 7: Example of traffic adaptive formation of mmWave meshed backhaul. **(a)** Formed mmWave meshed network at AM 3:00. **(b)** Formed mmWave meshed network at PM 3:00.