Setting of Protection Distance and Exclusion Distance and Effect on Emission Limits

Emission limits for electromagnetic disturbance sources are defined so that wanted radio signals can be received normally with a specified probability when the receiver is placed at a predefined protection distance from the disturbance source. The protection distance of 10 m is commonly assumed for setting emission limits in a residential environment and is regarded as the typical distance from a radio receiver to the nearest source. Moreover, the protection distance is, in some cases, related to the exclusion distance within which disturbance sources are ignored for the derivation of limits. However, there is no clear description in current international emission standards on how the protection distance is defined for deriving the limits. Since these distances strongly affect the limits, the setting of protection and exclusion distances appropriate for a given interference scenario is discussed in this report. The effect of the distances on the derived limits is also presented by assuming a simple two-dimensional model.