The overlapping zones (number of servers) criteria are used to establish the quality of the RF propagation environment from an interference point of view. The goal of the number of servers‘ criteria is to establish dominance and reduce the waste of network resources and degraded network performance that may occur when multiple servers exist in the same geographic area. The calculation is based on the Reference Signal (RS) signal levels of the servers.
Design KPI for Overlapping Zones (Number of Servers):
Within 5 dB of the best server
% area with 4 or more servers should be < 2%.
% of area with 2 or more servers should be < 30%.
Within 10dB of the best server
% of area with 7 or more servers should be < 2%.
The calculation is based on area importance. The clutter weights used for traffic spreading establishes the importance of the geographic area. The idea here is to focus the LTE design where LTE users are located (for example, core urban areas, convention centers, major stadiums, etc.) instead of areas within the LTE polygon with no users (for example, schrublands, forests, etc.)