  In this work, we address reliable communication of low-latency packets in the
presence of a full-duplex adversary that is capable of executing a jamming
attack while also being able to measure the power levels on various frequency
bands. Due to the presence of a strong adversary, first, we point out that
traditional frequency-hopping does not help since unused frequency bands may
not be available, and moreover, the victim's transition between the frequency
bands would be detected by the full-duplex adversary. Identifying these
challenges, we propose a new cooperative mitigation strategy, referred to as
the Semi-Coherent Fast-Forward Full-Duplex (SC-FFFD) relaying technique,
wherein the victim node, upon switching to a new frequency band, seeks the
assistance of its incumbent user, which is also a full-duplex radio, to
instantaneously forward its messages to the destination using a portion of
their powers. Meanwhile, the two nodes cooperatively use their residual powers
on the jammed frequency band so as to engage the adversary to continue
executing the jamming attack on the same band. Using on-off keying (OOK) and
phase-shift-keying (PSK) as the modulation schemes at the victim and the helper
node, respectively, we derive upper bounds on the probability of error of
jointly decoding the information symbols of the two nodes, and subsequently
derive analytical solutions to arrive at the power-splitting factor between the
two frequency bands to minimize the error of both the nodes. We also present
extensive simulation results for various signal-to-noise-ratio values and PSK
constellations to showcase the efficacy of the proposed approach.
