Experimental Analysis of Covert CDMA Against Energy and Cycle Detecting Adversaries

We study a three node code division multiple access (CDMA) network that maintains secrecy in the presence of a sophisticated adversary. It relies on a custom testbed of software-defined radios (SDRs). We evaluate the adversaries’ detection performance employing cyclostationarity and energy detection strategies while the two friendly CDMA links maintain the intended performance. We illustrate the tradeoff as a function of the detection error and link bit error as a function of the CDMA codeword length for the two detection schemes. It is observed that while energy detectors are sensitive to noise and other interference in the band that can degrade their performance with spread spectrum systems, the cyclostationary detectors are very sensitive to receiver imperfections.