# Channel Measurement and Modeling for 5G Urban Microcellular Scenarios
## 5 Conclusions  
The availability of reliable and accurate channel models is one of the crucial aspects for supporting the deployment of ultra-high capacity 5G networks. Proposed models that target a frequency range between 0.5 and 100 GHz and corresponding parameter tables still require further refinement and substantiation by statistically reliable measurement data in multiple frequency bands and various key scenarios. In this paper, the results of three UMi measurement campaigns performed in Berlin, Germany, have been presented, focusing on the PL and DS of the UMi access channel at 60 and 10 GHz. The evaluations are based on several million channel observations for each scenario, and full comparability has been ensured by uniform data processing. The findings aim to support the validation and improvement of current 5G channel models above 6 GHz. It revealed that the ground reflection has a strong impact on the LOS channel. Since its superposition with the LOS path results in a distinct regular fading of the first resolvable MPC, it will largely affect the instantaneous received power and channel conditions for a mobile user in a quasi-deterministic manner. State-of-the-art GSCMs do not consider this behavior, and it is strongly recommended to further investigate and incorporate this effect. \begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline \multirow{2}{*}{**Scenario**} & \multirow{2}{*}{**Freq. (GHz)**} & \multicolumn{3}{c}{**Measurement**} & \multicolumn{3}{c}{**Simulation**} & \multirow{2}{*}{**Valid. Range (m)**} \\ \cline{3-3} \cline{5-10}  & & \(\alpha\) & \(\beta\) & \(\epsilon\) & \(\alpha\) & \(\beta\) & \(\epsilon\) & \\ \hline OS-CC & 60.0 & \(-8.54\) & 0.0322 & 0.262 & \(-8.35\) & 0.0329 & 0.306 & 5–50 \\ SC-CC & 60.0 & \(-8.13\) & 0.0170 & 0.287 & \(-8.06\) & 0.0135 & 0.371 & 5–50 \\ SC-RA & 60.4 & \(-8.05\) & 0.0055 & 0.185 & - & - & - & 5–50 \\  & 10.0 & \(-7.84\) & 0.0024 & 0.216 & - & - & - & 5–50 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Parameters for distance-dependent DS model for line-of-sight (LOS): intercept point \(\alpha\), slope \(\beta\) and standard deviation \(\epsilon\). Figure 7: Measured DS as a function of distance with linear LS fit for ”street canyon, residential area” (SC-RA) scenario: (**a**) at 60 GHz; (**b**) at 10 GHz. At 60 GHz, the PL exponents under LOS conditions were found to be close to free-space propagation. A smaller value, namely 1.62, has been observed for 10 GHz in the narrow street canyon. The RMS DS shows a clear dependence on the scenario and its dimensions. Under LOS conditions, it is largest for the open square, and the values for the wide street canyon with modern buildings exceed the results obtained in the residential area. The DS is slightly larger at 10 GHz (data for narrow street canyon only) compared to 60 GHz for LOS, indicating only a weak frequency dependence. For NLOS, however, the difference is significant for the given scenario (median values are 38 and 16 ns for 10 and 60 GHz, respectively). The DS tendentially increases with distance for all measured UMi scenarios, but saturates around 100 ns. The distance dependence is strong for the open square scenario and the wide street in the city center, but less distinct in the narrow street canyon with residential buildings. It is well predicted by complementary RT simulations, although not all channel characteristics could be reproduced with satisfying accuracy. It is important to underpin such simulation results by measurements and to further improve the prediction tools. The research leading to these results has received funding from the European Union's Seventh Framework Programme FP7-ICT-2013-EU-Japan MiWEBA (Millimetre-Wave Evolution for Backhaul and Access) under grant agreement number 608637 and ICT-317669 METIS (Mobile and Wireless Communications Enablers for the Twenty-twenty Information Society).