Statistical analysis of radio frequency interference in microwave links using frequency scan measurements from multi-transmitter environments

Abstract

Radio frequency interference (RFI) comprises undesirable distortions from other frequency bands overlapping the specified band of operation. RFI contributes to increased detected power and temperature of the baseband processing units, resulting in considerable discrepancies in the received measurements. RFI mitigation techniques have been proposed to tackle this problem. However, the cost of implementing most RFI removal algorithms can be highly prohibitive. Removing such unwanted signals would involve removing a portion of the desired intelligence, leading to a potential loss of valuable information. The requirement for experimental frequency scans to detect, and mitigate RFI becomes important. Field measurements were conducted across three microwave links located in urban environments. The spectrum analyzer and a 0.6-meter antenna dish were used for the frequency scans at 6–8 GHz in horizontal and vertical polarizations. The availability of the desired frequencies, which is key to frequency planning is presented. The cumulative distribution functions, histogram and probability density functions of the measured data, which are crucial to determining the impact of interference on the microwave links, are presented. The statistical characteristics of the measured data are highlighted. Overall, the RFI data would provide insights on RFI detection and mitigation, leading to a high quality of service for the benefit of mobile subscribers.