  Multi-agent systems often communicate over low-power shared wireless networks
in unlicensed spectrum, prone to denial-of-service attacks. We consider the
following scenario: multiple pairs of agents communicating strategically over
shared communication networks in the presence of a jammer who may launch a
denial-of-service. We cast this problem as a game between a coordinator who
optimizes the transmission and estimation policies jointly and a jammer who
optimizes its probability of performing an attack. We consider two cases:
point-to-point channels and large-scale networks with a countably infinite
number of sensor-receiver pairs. When the jammer proactively attacks the
channel, the game is nonconvex from the coordinator's perspective. However,
despite the lack of convexity, we construct a saddle point equilibrium solution
for any multi-variate Gaussian distribution for the observations. When the
jammer is reactive, we obtain an algorithm based on sequential convex
optimization, which converges swiftly to first-order Nash-equilibria.
Interestingly, blocking the channel is often optimal when the jammer is
reactive, even when it is idle, to create ambiguity at the receiver.
