# Massive MIMO Indoor Transmissions at 38 and 65 GHz Applying Novel HBF Techniques for 5G
## 4 Results
### Throughput Analysis
#### 4.2.2 Performance According to Algorithm  
Table 6 shows the maximum distances achieved, related to the maximum throughputs obtained for both algorithms according to the frequency band, BW, and the different MCS  
Figure 7: Maximum throughput at 38 and 65 GHz using HBF algorithm (BW = 100, 200, and 400 MHz). schemes studied. In addition, the minimum SNR required to achieve each throughput is also indicated. At the 38 GHz frequency band, there is no improvement in throughput using the SFBC + HBF algorithm. For example, with a BW of 200 MHz and applying SFBC + HBF with the MCS 27 scheme, a throughput of 1.07 Gbit/s was achieved for all distances, while using the HBF algorithm and the MCS 19 scheme (lower modulation order), a higher throughput equal to 1.48 Gbit/s was achieved for all distances. Nonetheless, at the 65 GHz band, performance improvements can be achieved by applying SFBC techniques because the applied SNR was much lower (see Figure 6), which means that the HBF algorithm obtains worse results than the SFBC + HBF algorithm in situations of restricted SNR. From Table 6, for a BW of 100 MHz, the HBF algorithm was best up to 1.56 m, achieving a throughput of 0.37 Gbit/s by using the MCS 10 scheme and a minimum SNR of 8.6 dB. Between 1.56 and 2.26 m, it was better to use the SFBC + HBF algorithm, with a throughput of 0.18 Gbit/s, when the same scheme and a minimum SNR of 5 dB were applied. Finally, between 2.26 and 3.60 m, a maximum throughput of 0.08 Gbit/s was achieved by using the SFBC + HBF algorithm, along with using the MCS 4 scheme and a minimum SNR of \(-\)1.3 dB. However, using the HBF algorithm, the distance reached was only up to 2.26 m, with a throughput of 0.17 Gbit/s and a minimum SNR of 3.9 dB required. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Band (GHz)** & **MCS/Algorithm** & **BW (MHz)** & \begin{tabular}{c} **Th** \\ **(Gbit/s)** \\ \end{tabular}  & \ \begin{tabular}{c} **Max.** \\ **Distance (m)** \\ \end{tabular}  & \begin{tabular}{c} **Min. SNR** \\ **(dB)** \\ \end{tabular}  \\ \hline \multirow{6}{*}{65} & \multirow{4}{*}{4/HBF} & 100 & 0.17 & 2.26 & 3.9 \\ \cline{2-6}  & & 200 & 0.34 & 1.56 & 3.9 \\ \cline{2-6}  & & 400 & 0.68 & 0.95 & 3.9 \\ \cline{2-6}  & & 100 & 0.08 & 3.60 & \(-\)1.3 \\ \cline{2-6}  & & 200 & 0.17 & 3.17 & \(-\)2.2 \\ \cline{2-6}  & & 400 & 0.34 & 2.70 & \(-\)2.7 \\ \cline{2-6}  & & 100 & 0.37 & 1.56 & 8.6 \\ \cline{2-6}  & & 200 & 0 & - & - \\ \cline{2-6}  & & 400 & 0 & - & - \\ \cline{2-6}  & & 100 & 0.18 & 2.26 & 5.0 \\ \cline{2-6}  & & 200 & 0.37 & 1.56 & 5.8 \\ \cline{2-6}  & & 400 & 0.22 & 0.95 & 4.9 \\ \hline \multirow{6}{*}{38} & \multirow{2}{*}{19/HBF} & 100 & 0.74 & 4.10 & 14.9 \\ \cline{2-6}  & & 200 & 1.48 & 4.10 & 15.3 \\ \cline{2-6}  & & 400 & 2.97 & 4.10 & 15.4 \\ \cline{2-6}  & & 100 & 0.37 & 4.10 & 9.3 \\ \cline{2-6}  & & 200 & 0.74 &  
Therefore, by using the HBF algorithm, the throughput was increased by a factor of 2 (_N_s), compared to the SFBC + HBF case if the applied SNR exceeded the minimum SNR required. However, as SFBC + HBF needed lower SNRs, the Tx-Rx distance was increased by 1.34, 1.61, or 1.75 m when a BW of 100, 200, or 400 MHz, respectively, was used. For example, for a BW of 400 MHz, and using an MCS 4 scheme, the SFBC + HBF algorithm achieved up to 2.70 m by applying a minimum SNR that was 6.6 dB lower than the one needed by the HBF algorithm, to reach 0.95 m.  
In study [20], which applied a 16 QAM modulation, a BW of 800 MHz, and an EIRP = 53 dBm, a throughput of 1.2 Gbit/s was achieved to 3.5 m. However, in our case, at the 38 GHz band, when the HBF algorithm was applied, along with the MCS 10 (16 QAM) scheme, an EIRP = \(-9.3\) dBm, and a BW of 800 MHz (8 \(\times\) 100 MHz), the throughput achieved at 4.1 m was 1.4 Gbit/s. In study [21], 16 spatial-multiplexed streams, 256 BS antennas, adaptive modulation and coding (<256 QAM), and a bandwidth 500 MHz (100 MHz \(\times\) 5) were used.