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The sum-rate distortion function of generalized Gaussian multiterminal source coding is shown to coincide with that of joint encoding in the high-resolution regime if and only if the source-encoder bipartite graph and the undirected graphical model (also known as Gaussian Markov network or Gaussian Markov random field) of the source distribution satisfy a certain condition.
We study a setting where two source streams with different decoding deadlines must be transmitted over a burst erasure channel. The source streams are multiplexed into a single stream of channel-packets at the encoder and transmitted over a packet erasure channel. The decoder must recover the source-packets within each stream sequentially, by their corresponding deadlines. We consider the burst-erasure...
We consider the problem of covert communication over a state-dependent channel, where the transmitter has non-causal knowledge of the channel states. Here, “covert” means that the probability that a warden on the channel can detect the communication must be small. In contrast with traditional models without noncausal channel-state information at the transmitter, we show that covert communication can...
In this paper, a streaming transmission setup is considered where an encoder observes a new message in the beginning of each block and a decoder sequentially decodes each message after a delay of T blocks. In this streaming setup, the fundamental interplay between the coding rate, the error probability, and the blocklength in the moderate deviations regime is studied. For output symmetric channels,...
We introduce a new class of forward error correction (FEC) codes for VoIP communications which support different recovery delay depending on the channel conditions. Specifically, our proposed class of Dual-Delay (DD) codes can recover from challenging long bursts of losses with close to theoretical minimum delay so as to meet playback deadlines for recovered packets. They further improve conversational...
We introduce a new class of streaming codes that span across multiple source streams with different decoding deadlines. The encoder multiplexes two streams of source-packets into a single stream of channel-packets. The decoder must recover the source- packets within each stream sequentially, by their corresponding deadlines. We consider the burst-erasure channel model, and focus on the case when one...
It is well known that dispersed and burst packet losses introduce significantly different amount of distortions. Since perceptual models are typically content dependent, it is challenging to characterize how losses interact with concealment. This paper presents loss-pattern-aware distortion (LoPAD), a content-independent metric that explicitly models the impact of different loss patterns. LoPAD operates...
In the classic burst erasure channel, packets are consecutively erased in bursts between gaps of perfect communication. For the Burst Rank Loss Network, instead of a single-link erasure channel, there is a channel matrix that is rank-deficient for a burst of time before returning to full-rank. We establish the streaming capacity of the Burst Rank Loss Network and construct a new family of layered...
Regenerating codes are efficient methods for distributed storage in practical networks where node failures are common. They guarantee low cost data reconstruction and repair through accessing only a predefined number of arbitrary chosen storage nodes in the network. In this work we study the fundamental limits of required total repair bandwidth and the storage capacity of these codes under the assumption...
This paper investigates the two-user state-dependent Gaussian multiple access channel (MAC) with a helper. The channel is corrupted by an additive Gaussian state sequence known to neither the transmitters nor the receiver, but to a helper noncausally, which assists state cancellation at the receiver. Inner and outer bounds on the capacity region are first derived, which improve the previous bounds...
We consider streaming data transmission over a discrete memoryless channel. A new message is given to the encoder at the beginning of each block and the decoder decodes each message sequentially, after a delay of T blocks. In this streaming setup, we study the fundamental interplay between the rate and error probability in the central limit and moderate deviations regimes and show the following achievability...
In this paper, we consider the Gaussian diamond-wiretap channel that consists of an orthogonal broadcast channel from a source to two relays and a Gaussian fast-fading multiple access-wiretap channel from the two relays to a legitimate destination and an eavesdropper. For the multiple access part, we consider both the case with full channel state information (CSI) and the case with no eavesdropper's...
In smart grids, a smart meter communicates fine-grained information about a user's energy demand to the utility provider. A user's energy demand can be used to infer its private activities. Therefore, smart meters post a risk of violating privacy. This risk may be mitigated by using a rechargeable battery to obfuscate the user's demand. We investigate battery charging (and discharging) strategies...
In smart-metered systems, fine-grained time-series power usage data (load profile) is communicated from a user to the utility provider. The correlation of the load profile with a user's private activities leaves open the possibility of inference attacks. Using a rechargeable battery, the user can partially obscure its load profile and provide some protection to the private information using various...
We study a source-broadcasting problem involving an erasure broadcast channel with feedback. The receivers each require a certain fraction of a source sequence, and we are interested in the minimum latency, or transmission time, required to serve them all. We first show that for a two-user broadcast channel, a point-to-point outer bound can always be achieved. For broadcasting to three users, we propose...
We consider the problem of transmitting confidential messages over a two-user broadcast multiple-input multiple-output (MIMO) channel. Surprisingly, the capacity region of this setting under a covariance matrix constraint was shown by Liu et al. to be rectangular. That is, there is no tension, and both users can attain their respective MIMO wiretap capacities, simultaneously. In this work, we provide...
The broadcast channel with independent secret keys is studied. In this scenario, a common message has to be securely broadcast to two legitimate receivers in the presence of an eavesdropper. The transmitter shares with each legitimate receiver an independent secret key of arbitrary rate. These keys can either be used as one-time pads to encrypt the common message or can be interpreted as fictitious...
We study sequential transmission of Gauss-Markov sources over erasure channels under a zero decoding delay constraint. A two-stage coding scheme which can be described as a hybrid between predictive coding with limited past and quantization & binning is proposed. This scheme can achieve significant performance gains over baseline schemes in simulations involving i.i.d. erasure channels, and in...
We study the secure degrees of freedom (d.o.f.) of helper-assisted Gaussian wiretap channel with shared key between the transmitter and the helper. Given that the rate of the key scales with power as γ over 2 log SNR, we show that secure d.o.f. is min{1+γ over 2, 1}. The achievability proof combines real interference alignment with the artificial noise transmission technique. Using the shared key...
The column Hamming distance of a convolutional code determines the error correction capability when streaming over a class of packet erasure channels. We show that the column sum rank parallels column Hamming distance when streaming over a network with link failures. We prove rank analogues of several column distance properties and introduce a new family of convolutional codes that maximize the column...
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