## 4 Results and Discussion
### Path Loss, Packet Error Rate, and Throughput Estimation Measurements Using TG Platform  
We use the TG platform for directional PL measurements, as well as PER measurements and a maximum throughput estimation based on the transceiver's adaptive rate implementation, i.e., MCS selection. An angular scan is performed over an azimuthal range of 90\({}^{\circ}\) at the TX and RX nodes. From the angular scan, we select the TX-RX beam combination with minimum PL. For the LOS link, this is the beam with AoD and AoA 0\({}^{\circ}\), with PL 82.9 dB. The SNR of the frames is 20 dB, which results in an estimated throughput of 4.62 Gbps. One reflected path is measured with the TG platform, with a PL of 100 dB, and an AoD and AoA of 40\({}^{\circ}\). The SNR for this reflected component is 12 dB.  
For link NLOS1, with both nodes positioned in the direction of the obstructed LOS path, the minimum PL of 105.2 dB is found for a beam combination TX \(-25.3^{\circ}\) and RX \(-32.3^{\circ}\). If we rotate the nodes, both facing in the direction of window 3, the minimum PL decreases to 87.5 dB, as can be seen in Figure 7. This path corresponds to a first-order reflection on the window and the corresponding SNR of 15 dB allows a maximum PHY data rate of 3.85 Gbps. Reflections on the wall are also visible in the angular PL profile, e.g., with PL 98 dB for TX 35.2\({}^{\circ}\) and RX 22.5\({}^{\circ}\). For link NLOS2, the minimum PL of 106 dB is found for AoD 47.8\({}^{\circ}\) and AoA 53.4\({}^{\circ}\), i.e., via a first-order wall reflection. The SNR of 10 dB also results in a throughput of 3.85 Gbps. The minimum PL for the NLOS scenarios, measured with the TG platform, is higher than the minimum PL measured with the channel sounder. By using an omnidirectional transmit antenna with the channel sounder, more reflected power is received, whereas with the double-directional TG platform (and sequential beamsteering), less transmitted power is received.  
As no adaptive beamforming is used, the estimated throughput drops when a person obstructs the communication link. For the LOS link, the PL increases from 83 dB to 120 dB, which is in line with the human blockage model from [35], and the SNR decreases from 20 dB to 3 dB. The decreased SNR results in a throughput estimate decrease from 4.62 Gbps to 962 Mbps. It only decreases to 3.85 Gbps if the reflected path is used, with AoD and  
Figure 7: Angular path loss profile measured with Terragraph platform for link NLOS1 with distance 4.7 m.  
AoA 40\({}^{\circ}\). When a person obstructs the reflected path for the NLOS scenarios, the SNR also decreases to 3 dB. The throughput decreases to 962 Mbps.  
Figure 8 shows the measured PER as a function of the MCS index. For the LOS link, the packet error rate is below 4% for all MCS indices. For the NLOS scenarios, the PER starts increasing from MCS index 4. E.g., for link NLOS2, there is 50% packet loss for MCS index 6. Starting from MCS index 7, all packets are lost. The PER measurements indicate that the throughput estimation of the TG sounder, which is based on the measured SNR, is optimistic, but even for NLOS scenarios, a throughput exceeding 1.25 Gbps is expected, i.e., a data rate corresponding to MCS index 5.