# <center> **Assignment 1** </center> ###### tags: `O-RAN` `IVC` `5G O-RAN` `ITB NTUST 5G course` > Date: 22/07 ## **Channel Model (Pathloss and Quadriga Channel Model)** ### <center> **Assignment 1A** </center> ![](https://i.imgur.com/4HvD24V.jpg) **1. Direct LOS = Green 2. Reflected path one bounce = Orange 3. Reflected path two bounces = Purple 4. Diffracted path = Blue 5. Transmission through wall or window = Red** ### <center> **Assignment 1B** </center> #### 1. Path gain for 2-ray model ![](https://i.imgur.com/wOV8UdD.jpg) The 2-ray model is a multipath radio propagation model which predicts the path losses between a transmitting antenna and a receiving antenna when they are in line of sight (LOS). Rapid power fluctuations due to the interference between the 2 paths. #### 2. Path gain for 3GPP Urban Microcell (Line of Sight) ![](https://i.imgur.com/aEX1jEI.jpg) UMi (Urban Microcelluler) In the double-directional channel model, the multipath components are described by the delays and the directions of departure and the direction of arrival. Each multipath component is scaled with a complex amplitude gain. Then the double directional channel impulse response is composed of the sum of the generated double-directional multipath components. The doubledirectional channel model provides a complete omnidirectional statistical spatial channel model (SSCM) for both LOS and NLOS scenarios in the UMi environment. In the figure, there is no reflection and it makes the fluctuation haven't rapid occurs. #### 3. Path gain for 3GPP Urban Microcell with 1 reflection ![](https://i.imgur.com/8BlAcsw.jpg) UMi (Urban Microcelluler) include Ground Reflection: In the double-directional channel model, the multipath components are described by the delays and the directions of departure, and the direction of arrival. Each multipath component is scaled with the interaction of the direct and ground reflected waves to produce regular sharp amplitude nulls in the volume occupied by the EUT or receiving/measuring antenna. So, in the graph shown the rapid fluctuations occurs. ### **Conclusion** Each figure has different fluctuation and reflections, so it make have different power of the signal.