Channels with Action Dependent States and Additional Private Messages

Abstract

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-causal knowledge of the state-process at the channel encoder, a single letter characterization of the capacity is known in the discrete memoryless case.We consider the action dependent state channel where an additional private message needs to be communicated by the channel encoder. In addition, we consider a common reconstruction (CR) of the state at the channel encoder and decoder. Capacity characterizations for the discrete memoryless and Gaussian versions are presented. As a consequence, we settle the capacity characterization of the Gaussian action dependent channel with only a common message and CR. We further show that the availability of strictly causal state feedback to the action encoder, even with randomization allowed, does not improve the capacity of the action dependent state channel. I. INTRODUCTIONThe problem of coding for channels with state was introduced in the seminal paper by Shannon [1], wherein causal state information was assumed at the encoder. The capacity for the non-causal setting was established by Gelfand and Pinsker [2]. In these models, the state process is assumed to be given by nature. Motivated by applications involving multi-stage encoding (for instance, two-stage recording on a magnetic storage device), Weissman [3] introduced the notion of a channel with action dependent states (ADSC). In this setting, the transmitter can take actions that influence the formation of channel states in the first stage, and the encoding in the second stage is based upon the channel state sequence so generated and the message. Notice that the actions play a dual role of message communication as well as controlling the channel states. The capacity of this model was derived in [3].Following [3], the action-dependent framework has been extended in several directions. Permuter et al.[4] studied the source coding dual in which the decoder can take actions based on the observed compression index that influence the formation of side information. Asnani et al.[5] considered a setting in which the encoder as well as the decoder can take probing actions to learn the channel state, with a cost constraint associated with each. Choudhuri et al.[6] considered causal state communication over an action-dependent channel and characterized the trade-off between message communication and state estimation distortion. Ahmadi et al.[7] studied action-dependent channels with the additional constraint of common reconstructions (CR) [8] of the state at the encoder and decoder. Recently, Kittichokechai et al.[9] studied source and channel coding settings with action-dependent states and CR constraints, wherein the actions control the partial channel state information available at the encoder...

VME Readout at and Below the Conversion Time Limit

“…The livetime of the system is thus given by whichever of (1) or (7) is smaller: For shadow readout, ∆t is expected to be approximately equal to the gate and conversion time t g + t c . The livetime characteristics of the different readout schemes are illustrated in Fig.…”

“…of the module buffer. This mode, however, is only available for the Silena S9418 front-end modules in MIDAS [6], and the LAMPS is hampered by large overhead times in the associated CAEN VME controller [7]. However, the above systems are exceptions, and the multi-event buffers are often not utilized to their full extent, or not at all.…”