Detailed Investigation of the Vulnerability of an OFDM based WLAN Connection to CW Signal Interference

A new measurement setup for investigating the interference behaviour of Continuous Wave signals on packet based information transfer of the IEEE 802.11 standard in the 2.4 GHz ISM band is presented in this paper. The main focus of the measurement setup is a low level of complexity to perform reproducible results. A high degree of automation allows very detailed measurements of the Packet Error Rate over a wide range of CW frequencies and magnitudes. The measurement results are divided into depictions of the Packet Error Rate and Frame Check Sequence errors. Two different IEEE 802.11 standards with each using a 64-QAM and a BPSK modulation are presented in order to demonstrate the new measurement setup and investigate the vulnerability behaviour against narrow band interferers. Especially the subcarriers of the OFDM based WLAN signal tend to be the most vulnerable frequencies on higher coding schemes. The Pilot sub carrier frequencies in particular have proven to be even more vulnerable than the Data subcarriers.