Capacity of Gaussian Arbitrarily-Varying Fading Channels

In this work, we explore the capacity of point-to-point fast fading channels in the presence of an adversary. We assume that the fading gains are known at the decoder; they may also be known to the encoder and/or adversary. If the adversary does not know the gains, then the capacity is equal to the capacity of the corresponding fading channel with the noise variance raised by the power of the jammer. If the gains are available at the jammer, then the capacity is determined by the worst-case noise variance as a function of the channel gain subject to the jammer's power constraint; if the jammer has enough power, then it can imitate the legitimate user's channel, causing the capacity to drop to zero.