## 5 Performance Evaluation  
In order to evaluate the contribution of the ABT-RRMAC, we perform simulations by considering three different configurations of antennas in the nodes: omnidirectional with round-robin scheduling, SASs with round-robin (RR-MAC), and our proposed ABT-RRMAC that uses SAS adaptive array antennas. Simulations are accomplished by varying the number of sectors and then the node mobility speed. The following table summarizes the main simulation parameters. Simulations have been accomplished by using 20 different seeds and extracting the confidence intervals obtained by the repetitions considering a confidence level set to 95%. The traffic is represented by the UDP (user datagram protocol) data packets randomly generated (based on the simulation seed) by different couples of nodes. The number of nodes is set to 50 and couples of nodes involved in the data traffic exchange is one half with respect to the total number of nodes in the network. In addition, the channel is moderately affected from noise (\(-80\) dBm), with SASs that have the main beam toward 45\({}^{\circ}\). For the first set of simulations, we consider an unbalanced distribution of data (worst conditions) traffic by concentrating on the main fraction of communications in the first sector of the plane; therefore, nodes move very slowly (2 mps) in the network and the size of the queues is set to 5. The first evaluated statistic is the energy consumption of nodes by varying the number of sectors. The plots in Figure 9 illustrate the energy consumption of nodes (expressed in Joules) in the function of the number of sectors (observe that the term \"\(N\). _Sector_\" used in plots of Figure 9 is related to the progressive number ID assigned to each sector and does not identify \(N_{\text{s}}\)). In Figure 9, it can be observed how the main fraction of consumption is related to Sector 1, the sector in which the traffic is mostly focused with respect to others. When omnidirectional antennas and the round-robin scheduler are used, the distribution of energy consumption among sectors is very unbalanced; this trend is mainly due to the static time slot assigned by the scheduler, that, in this case, is the same of all sectors; this feature results in an inefficient distribution of the energy in the sectors. Consequently, the total energy consumption is considerable (almost 298 J). However, the same behavior is maintained in Figure 9 in which, when SAS modules are used, i a better distribution of the consumed energy among sectors can be highlighted. In Figure 9, it appears clear that, as the number of sectors increases, the maximum amount of consumed energy is reduced; in the case of omnidirectional antennas, the imbalance remains unchanged. However, the use of the SAS allows one to decrease considerably the maximum energy amount that is further reduced when the ABT-RRMAC approach is employed (44.54 against 88.27 registered in the omnidirectional case). Finally, Figure 9d further emphasizes the impact of the proposed approach, flowing in an overall balancing of the energy consumption. In summary, the dynamic allocation of the beamforming time allows one, independently from the number of sectors, to optimize the distribution of the energy also leading to a reduction of the overall consumed energy; indeed the registered values of total consumed energy in the RR-MAC case in the function of the number of sectors are 248.33, 255.14, 250.91, and 272.32 J against values of 187.89, 216.26, 211.81, and 235.37 J registered when the ABT-RRMAC is used.