On Reliable Communication Under Reactive Adversaries With Generalized Energy Detectors

Reactive jamming adversaries refer to those adversaries that inject jamming energy on the victim's frequency band and also monitor the same band for detecting countermeasures, thereby trapping the victim. Existing threat models under this class have studied adversaries that detect countermeasures by monitoring only the average energy on the victim's band. Inspired by the recent developments in multi-band processing capabilities of cognitive radios, in this work, we propose a stronger threat model wherein the jamming adversary measures several generalized energy statistics of the observed symbols over all the network frequencies to detect countermeasures. Identifying that existing countermeasures do not provide the desired covertness results against this threat model; we propose a new cooperative mitigation strategy wherein the victim takes the assistance for a helper radio in the network to reliably communicate its message to the destination by minimally disturbing the statistical distribution and the instantaneous energies of the symbols in the network. Through rigorous analyses on the reliability and covertness measures, interesting optimization problems are solved to compute the optimal division of energy resources between the victim and the helper so as to jointly minimize their error-rates while ensuring that the adversary fails to detect the countermeasure with high probability.