In this work, the role of noisy feedback in enhancing the secrecy capacity of the wiretap channel is investigated. A model is considered in which the feed-forward and feedback signals share the same noisy channel. More specifically, a discrete memoryless modulo-additive channel with a full-duplex destination node is considered first, and it is shown that a judicious use of feedback increases th...

In this paper, we study a MIMO fading broadcast channel where each receiver has perfect channel state information while the channel state information at the transmitter is acquired by explicit channel feedback from each receiver through capacity-constrained feedback links. Two feedback schemes are considered, i.e., the analog and digital feedback. We analyze the achievable ergodic rates of zero...

To be correctly mastered, brain-computer interfaces (BCIs) need an uninterrupted flow of feedback to the user. This feedback is usually delivered through the visual channel. Our aim was to explore the benefits of vibrotactile feedback during users' training and control of EEG-based BCI applications. A protocol for delivering vibrotactile feedback, including specific hardware and software arrang...

Dynamic resource allocation based on the current channel state is a promising strategy to increase the capacity of wireless links. In this paper, the optimum accessing and resource allocation scheme for fading multiple–access channels with partial CSI at the transmitters are found. Partial knowledge of the fading states is a reasonable assumption for systems which provide a low rate feedback ch...

The capacity region of m-user non-white Gaussian multiple access channel without feedback was exactly obtained. But it is not yet obtained in the feedback case without the upper bound of total capacity. We give the outer bound of capacity region in muser non-white Gaussian multiple access channel with noiseless and nodelayed feedback in general. Finally we remark that there are three types of o...

Back-channel feedback is required in order to build spoken dialog systems that are responsive. This paper reports a model of back-channel feedback in Japanese dialog. It turns out that a low pitch region is a good clue that the speaker is ready for back-channel feedback. A rule based on this fact matches corpus data on respondents' production of backchannel feedback. A system based on this rule...

The symmetric linear deterministic interference channel (LD-IC) with partial feedback is considered. Partial feedback for the symmetric LD-IC models a scenario in which the top l most-significant-bits of the channel output of receiver j are received as feedback at transmitter j, for j = 1, 2. It is shown that the LD-IC with partial feedback can serve as a good approximation to the Gaussian inte...

A receiver transforms correlated channel state information (CSI) to an uncorrelated sparse CSI vector by using a principal component analysis (PCA), and feeds it back to a transmitter. The PCA extracts essential information from the CSI without redundancy that arises from the highly correlated antennas. The transmitter then recovers the original CSI through the inverse transformation of the fee...

We characterize the symmetric capacity to within 1.7075 bits/s/Hz for the two-user Gaussian interference channel with feedback. The result makes use of a deterministic model to provide insights into the Gaussian channel. We derive a new outer bound to show that a proposed achievable scheme can achieve the symmetric capacity to within 1.7075 bits for all channel parameters. From this result, we ...

There has recently been significant interest in feedback stabilization problems over communication channels, including several with bit rate limited feedback. Motivated by considering one source of such bit rate limits, we study the problem of stabilization over a signal-to-noise ratio (SNR) constrained channel. We discuss both continuous and discrete time cases, and show that for either state ...