On Jammer Power Allocation Against OFDM Signals in Fading Channels

Jamming behavior in fading channels is not well understood when compared to additive white Gaussian noise channels. Specifically, it is not clear how or if a jammer should perform power control in the presence of a time or frequency-selective fading channel between itself and the victim receiver. Such a problem is relevant in the context of a) orthogonal frequency division multiplexing (OFDM)-based signaling systems, where the jammer must optimize its power allocation across a frequency-selective channel and b) single-carrier systems where the jammer must optimize its power allocation across a time varying fading channel in order to optimally attack the victim receiver. In this paper, we address this problem by studying jammer power allocation across a fading channel in order to maximize the error probability of a victim receiver that uses orthogonal frequency division multiplexing (OFDM)-based signaling. We propose an iterative algorithm to determine a jammer power allocation that performs up to 4 dB better, in terms of the victim signal power required to attain the same error rates, than other commonly used power allocation strategies. We also show that as the jammer's knowledge about the victim decreases, the gains obtained by using the proposed jamming strategy reduce but still performs better than the commonly used jamming strategies.