Evaluation of Adaptive Interference Cancellation in Chirp Spread Spectrum-based Communication Systems

For data transmission in heavily distorted indoor environments, chirp-based spread spectrum systems operating in the 2.45 GHz ISM band are well applicable. The robustness of spread spectrum systems against narrow band jammers is given by their compression gain, which is defined by the timebandwidth product of the spreading signal. Using chirp matched filter systems, jammers can pass through the receiver filter and are only weighted by its transfer function. Dividing the receiver chirp filter into time (equivalent to frequency) intervals, a jammer can be suppressed by switching off the corresponding frequency interval, leading to an increased jamming robustness. Due to its simplicity, this is suitable even for low cost systems. Theoretical and experimental results prove the capability of the method. Keywords—spread spectrum, chirp, matched filter, FPGA design