scholarly journals Robust Signaling for Bursty Interference

Entropy ◽  
2018 ◽  
Vol 20 (11) ◽  
pp. 870 ◽  
Author(s):  
Grace Villacrés ◽  
Tobias Koch ◽  
Aydin Sezgin ◽  
Gonzalo Vazquez-Vilar
Keyword(s):  
Achievable Rate ◽  
Interference Channel ◽  
Receiver Side ◽  
Causal Knowledge ◽  
Bernoulli Process ◽  
Channel State ◽  
Reliable Communication ◽  
State Information ◽  
Coding Strategy ◽  
Bursty Interference

This paper studies a bursty interference channel, where the presence/absence of interference is modeled by a block-i.i.d. Bernoulli process that stays constant for a duration of T symbols (referred to as coherence block) and then changes independently to a new state. We consider both a quasi-static setup, where the interference state remains constant during the whole transmission of the codeword, and an ergodic setup, where a codeword spans several coherence blocks. For the quasi-static setup, we study the largest rate of a coding strategy that provides reliable communication at a basic rate and allows an increased (opportunistic) rate when there is no interference. For the ergodic setup, we study the largest achievable rate. We study how non-causal knowledge of the interference state, referred to as channel-state information (CSI), affects the achievable rates. We derive converse and achievability bounds for (i) local CSI at the receiver side only; (ii) local CSI at the transmitter and receiver side; and (iii) global CSI at all nodes. Our bounds allow us to identify when interference burstiness is beneficial and in which scenarios global CSI outperforms local CSI. The joint treatment of the quasi-static and ergodic setup further allows for a thorough comparison of these two setups.

scholarly journals Secure Retrospective Interference Alignment

Entropy ◽  
2019 ◽  
Vol 21 (11) ◽  
pp. 1092
Author(s):  
Mohamed Seif ◽  
Ravi Tandon ◽  
Ming Li
Keyword(s):  
Degrees Of Freedom ◽  
Interference Alignment ◽  
Square Root ◽  
Interference Channel ◽  
Channel State ◽  
State Information ◽  
Two Phases ◽  
Constrained Models ◽  
User Interference ◽  
Previous Phase

In this paper, the K-user interference channel with secrecy constraints is considered with delayed channel state information at transmitters (CSIT). We propose a novel secure retrospective interference alignment scheme in which the transmitters carefully mix information symbols with artificial noises to ensure confidentiality. Achieving positive secure degrees of freedom (SDoF) is challenging due to the delayed nature of CSIT, and the distributed nature of the transmitters. Our scheme works over two phases: Phase one, in which each transmitter sends information symbols mixed with artificial noises, and repeats such transmission over multiple rounds. In the next phase, each transmitter uses the delayed CSIT of the previous phase and sends a function of the net interference and artificial noises (generated in previous phase), which is simultaneously useful for all receivers. These phases are designed to ensure the decodability of the desired messages while satisfying the secrecy constraints. We present our achievable scheme for three models, namely: (1) K-user interference channel with confidential messages (IC-CM), and we show that 1 2 ( K - 6 ) SDoF is achievable; (2) K-user interference channel with an external eavesdropper (IC-EE); and 3) K-user IC with confidential messages and an external eavesdropper (IC-CM-EE). We show that for the K-user IC-EE, 1 2 ( K - 3 ) SDoF is achievable, and for the K-user IC-CM-EE, 1 2 ( K - 6 ) is achievable. To the best of our knowledge, this is the first result on the K-user interference channel with secrecy constrained models and delayed CSIT that achieves an SDoF which scales with K , square-root of number of users.

scholarly journals Wiretap Channel with Rate-Limited Channel State Information

2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
Xinxing Yin ◽  
Liang Pang ◽  
Zhi Xue
Keyword(s):  
Channel State Information ◽  
Channel Coding ◽  
Transmission Rate ◽  
Information Leakage ◽  
Achievable Rate ◽  
Security Model ◽  
Channel State ◽  
Wiretap Channel ◽  
State Information ◽  
Gaussian Case

We revisit a channel coding problem where the channel state information (CSI) is rate-limited (or coded) and available to the channel encoder. A wiretapper is added into this model, and the confidential message is intended only for the legal receiver and should be kept from being eavesdropped by the wiretapper. Equivocation analysis is provided to evaluate the level of information leakage to the wiretapper. We characterize an achievable rate-equivocation region as well as an outer bound for this security model. To achieve the rate-equivocation triples, we propose an efficient coding scheme, in which the coded CSI serves as the CSI for the channel encoder, based onGel’fand and Pinsker’s codingandWyner’s random coding. Furthermore, an example of Gaussian wiretap channel with rate-limited CSI is presented, of which a lower bound on the secrecy capacity is obtained. By simulation, we find there exists an optimal rate of the coded CSI at which the biggest secrecy transmission rate of the Gaussian case is achieved.

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