Channels with Action Dependent States and Additional Private Messages

In channels with action dependent states, a message is conveyed using two encoders operating sequentially, viz.an action encoder and a channel encoder. The actions drive the output of a discrete-memoryless channel (DMC),which in turn forms the state process for the DMC between the channel encoder and receiver. Assuming non-causalknowledge of the state-process at the channel encoder, a single letter characterization of the capacity is known inthe discrete memoryless case.We consider the action dependent state channel where an additional private message needs to be communicatedby the channel encoder. In addition, we consider a common reconstruction (CR) of the state at the channel encoderand decoder. Capacity characterizations for the discrete memoryless and Gaussian versions are presented. As aconsequence, we settle the capacity characterization of the Gaussian action dependent channel with only a commonmessage and CR. We further show that the availability of strictly causal state feedback to the action encoder, evenwith randomization allowed, does not improve the capacity of the action dependent state channel.

Relay Channel with Non-causal State Information at the Source and Relay

A state-dependent discrete memoryless relay channel is considered, with non-causal side informationavailable at both the sender and the relay. The capacity of thisrelay model is an open problem. We improve upon the knownachievable regions for this setting, in addition to proving an outerbound. The key idea in the proof of achievable region is to employa modified decode-forward scheme. The characterization is thenextended to a relay broadcast setting, where an improved innerbound over existing schemes and an outer bound are exhibited.