## 4 Results and Discussion
### Impact of the Number of Users and the Pilot Reuse Factor on Area Throughput  
The comparison between the proposed estimator and the existing estimator utilizing the parameter area throughput with the number of antenna per UE is shown in Figure 13.  
Figure 11: Energy efficiency versus the number of antennas per UE for fully centralized processing with the MMSE combiner at K = 10, L = 4, \(\tau_{c}\) = 200, and w = 2. Figure 12: Energy efficiency versus the number of access points for fully centralized processing with the MMSE combiner at K = 10, L = 4, \(\tau_{c}\) = 200, and w = 2. The area throughput increased as the number of antennae per UE increased for M values of 20, 40, and 80; however for an M value of 10, the area throughput initially increased and then decreased. The suggested estimator attained area throughput at \(\rm{T}=3792\) Mbit/s/km\({}^{2}\) at \(\rm{N}=6\) and \(\rm{M}=80\), whereas the existing estimator attained AT = 3467 Mbit/s/km\({}^{2}\) at \(\rm{N}=6\) and \(\rm{M}=80\). The proposed estimator enhanced the performance by 9.374% at this point. For \(\rm{M}=10\), the proposed estimator and the existing estimator maximally reached the area throughput at \(\rm{N}=3\), which are 1612 Mbit/s/km\({}^{2}\) and 1491 Mbit/s/km\({}^{2}\), respectively. The length of the pilot is 60 since \(\rm{w}=1\), \(\rm{N}=6\), and \(\rm{K}=10\). Figure 14 shows the effect of users on the area throughput with varied numbers of APs and at different numbers of antennae per UE. When the number of users increased, the area throughput reduced. The proposed estimator achieved area throughput = 3051.17 Mbit/km\({}^{2}\) at \(\rm{N}=4\) and \(\rm{M}=80\), whereas for the existing estimator, the area throughput = 2895.84 Mbit/km\({}^{2}\) at \(\rm{N}=4\) and \(\rm{M}=80\). As the number of APs increased, the throughput also increased. At \(\rm{N}=3\) and \(\rm{M}=40\), the area throughput achieved by the existing and proposed estimators became 2405.29 Mbit/km\({}^{2}\) and 2511.62 Mbit/km\({}^{2}\), respectively. At \(\rm{N}=4\) and \(\rm{M}=20\), the area throughput achieved by the existing and proposed estimators became 2226.1 Mbit/km\({}^{2}\) and 2226.7 Mbit/km\({}^{2}\), respectively. The area throughput attained by the proposed and existing estimators for \(\rm{M}<20\) is similar. The pilot length became 60 since \(\rm{K}=15\), \(\rm{N}=4\), and \(\rm{w}=1\). The pilot length depends on the number of users, the number of antennae per UE, and the pilot reuse factor; i.e., as the number of users increased, the pilot length also increased. Figure 15 shows that the effect of the pilot reuse factor on the area throughput varied across the number of antennae per UE at different numbers of APs when the pilot reuse factor was raised to two. The proposed estimator achieved area throughput = 1325 bit/km\({}^{2}\) at \(\rm{N}=6\) and \(\rm{M}=80\), whereas for the existing estimator, the area throughput = 1200 Mbit/km\({}^{2}\) at \(\rm{N}=6\) and \(\rm{M}=80\). The proposed estimator improves the performance by 10.42% at this point. At \(\rm{N}=4\) and \(\rm{M}=40\), the area throughput achieved by the existing and proposed estimators became 1050 Mbit/km\({}^{2}\) and 1150 Mbit/km\({}^{2}\). The area throughput values attained by the proposed and existing estimators for \(\rm{N}<2\) are very close. The maximum area throughput reached by the proposed estimator occurred at \(\rm{N}=3\), i.e., 1400 Mbit/km\({}^{2}\), whereas for the existing estimator, an area throughput of 1350 Mbit/km\({}^{2}\) was reached. As the pilot reuse factor increased from \(\rm{w}=1\) to \(\rm{w}=2\), the area throughput decreased. As a result, the gap between the proposed and existing estimators also decreased. The  
Figure 13: Area throughput versus the number of antennas per UE for fully centralized processing with the MMSE combiner at \(\rm{K}=10\), \(\rm{L}=4\), \(\rm{\tau}_{c}=200\), and \(\rm{w}=1\). pilot length became 30 since K = 10, N = 6, and w = 2, which means that the pilot length decreased as the pilot reuse factor increased.