Jamming in fading Multiple Access Channels

A fading Multiple Access Channel with a jammer is considered and a non-cooperative game between the two users and the jammer is formulated. Here, both the user-receiver links as well as the jammer-receiver link are time-varying fading links. The decoder employed is a successive cancellation decoder. To begin with, the decoder announces a scheme where it shares with the users and the jammer their decoding order as a function of the combined channel state observed. Equivalently, this scheme is a partition of the space of all channel states into two sets. For the observed channel states belonging to the first set, the first user is decoded followed by the second, while for the states belonging to the other set, the decoding order is reversed. Each user aims to maximize its own rate whilst treating the other user as noisy interference. The adversarial jammer chooses its channel input so as to minimize overall throughput. We show that for every decoding scheme announced by the decoder, the resulting game has a unique Pareto-dominated Nash equilibrium. Also, connections with relevant existing results on fading Multiple Access Channels with a jamming adversary, specifically w.r.t the equilibrium sum-rate operating point, are discussed.