How to Do Path Reflection Analysis with MLinkPlanner 1.2

Get free trial at https://www.wireless-planning.com Reflection analysis allows the user to identify possible specular reflection points on the hop and evaluate the application of various specular reflection reduction methods. To open the Reflection Analysis window, click the corresponding button on the main panel. You can change the following parameters: - k-factor, for which the reflection points are searched - Polarization - Vertical or Horizontal. To reduce the effect of the reflected wave, it is recommended to select vertical polarization - Reflecting surface type. The type of surface from which the reflection occurs. Each surface types has its own values of Relative dielectric constant and Electrical conductivity. - Relative dielectric constant is a dimensionless parameter. Is automatically determined depending on the Reflecting surface type, but can be modified by the designer. - Electrical conductivity [ohm‐1 m‐1]. Is automatically determined depending on the Reflecting surface type from above, but can be modified by the designer. - If check-box “Consider clutters on the reflected paths” is active, then when the incident or reflected rays intersect with ground obstacles (forest or trees), these rays will be screened. The path profile displayed all possible direct and ground-reflected rays for the Main-Main paths, and in a space diversity configuration for the Main-Diversity and Diversity-Main paths. The table below will show the distances to and clearance at each of the reflection points. It is recommended that reflection points be determined for large k-factor values (at least 10). You can view Relative Rx Power vs. k-factor chart for any reflection point and any of the Main-Main, Main-Diversity or Diversity-Main paths by clicking on the desired point in the table. Note that you need to specify the beamwidth for each of the antennas in Site A and Site B in order to calculate Relative Rx Power vs. k-factor chart. In addition to Relative Rx Power vs. k-factor, you can also display Time Delay vs. k-factor chart. On this plot the relative signal delay in nanoseconds between the direct and reflected signal is displayed for each of the Main–Main, Main–Diversity or Diversity–Main paths. If the reflected signal delay is greater than 10-20 nanoseconds, performance problems on high capacity systems can occur. If there is specular reflection along the path and you are not going to use space diversity, the application can estimate the effectiveness of the following methods for reducing the effect of the reflected ray on the resulting signal for systems without space diversity recommended in Rec. ITU-R P.530-17: - increase of path inclination; - shielding of the reflection point; - moving of the reflection point to the poorer reflecting surface; - reduction of path clearance; - choice of vertical polarization. In most cases, these methods (except for the last one) are limited to selecting the primary antenna height on the right or left. The most efficient way to eliminate the effect of specular reflection is to use space diversity techniques. The most often used technique is vertical space diversity. MLinkPlanner allows you to determine receive antenna heights with enough spacing to maintain an uncorrelated direct and reflected signal, so that when the receive signal level for the primary antenna is zero (in fade), the signal is near the peak for the diversity antenna, and vice versa. The right-hand part of the window displays the heights of diversity antennas determined based on optimum antenna spacing as per Rec. ITU-R P.530-17, i.e. the case when received signal levels at the primary and secondary antennas must display a maximum difference (maximum and minimum) across the full range of the k-factor to minimize the effect of specular reflection on the received signal level.