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Paper Detail

Paper IDI.5.5
Paper Title Quadratically Constrained Two-way Adversarial Channels
Authors Yihan Zhang, The Chinese University of Hong Kong, China; Shashank Vatedka, Indian Institute of Technology, Hyderabad, India; Sidharth Jaggi, The Chinese University of Hong Kong, China
Session I.5: Network Information Theory
Presentation Lecture
Track Network Information Theory
Manuscript  Click here to download the manuscript
Virtual Presentation  Click here to watch in the Virtual Symposium
Abstract We study achievable rates of reliable communication in a power-constrained two-way additive interference channel over the real alphabet where communication is disrupted by a power-constrained jammer. This models the wireless communication scenario where two users Alice and Bob, operating in the full duplex mode, wish to exchange messages with each other in the presence of a jammer, James. Alice and Bob simultaneously transmit their encodings $ \underline{x}_A $ and $\underline{x}_B $ over $ n $ channel uses. It is assumed that James can choose his jamming signal $ \underline{s} $ as a noncausal randomized function of $ \underline{x}_A + \underline{x}_B $, and the codebooks used by Alice and Bob. Alice and Bob observe $ \underline{x}_A+\underline{x}_B +\underline{s}$, and must recover each others' messages reliably. In this article, we provide upper and lower bounds on the capacity of this channel which match each other and equal $ \frac{1}{2}\log\paren{\frac{1}{2} + \mathsf{SNR}} $ in the high-$\mathsf{SNR}$ regime (where $\mathsf{SNR}$, \emph{signal to noise ratios}, is defined as the ratio of the power constraints of the users to the power constraint of the jammer). We give a code construction based on lattice codes, and derive achievable rates for large $\mathsf{SNR}$. We also present upper bounds based on two specific attack strategies for James. Along the way, sumset property of lattices for the achievability and general properties of capacity-achieving codes for memoryless channels for the converse are proved, which might be of independent interest.

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2021 IEEE International Symposium on Information Theory

11-16 July 2021 | Melbourne, Victoria, Australia

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