  This paper addresses the problem of distributed state estimation via multiple
access channels (MACs). We consider a scenario where two encoders are
simultaneously communicating their measurements through a noisy channel.
Firstly, the zero-error capacity region of the general M-input, single-output
MAC is characterized using tools from nonstochastic information theory. Next,
we show that a tight condition to be able to achieve uniformly bounded state
estimation errors can be given in terms of the channel zero-error capacity
region. This criterion relates the channel properties to the plant dynamics.
These results pave the way towards understanding information flows in networked
control systems with multiple transmitters.
