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arXiv:2503.07804 · IEEE International Symposium on Information Theory (ISIT)

Simultaneous Decoding of Classical Coset Codes over 3–User Quantum Interference Channel : New Achievable Rate Regions

Fatma Gouiaa, Arun Padakandla

Published Jun 1, 2026• 0 citations
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Abstract

We undertake a Shannon theoretic study of the problem of communicating bit streams over a 3-user classical-quantum interference channel (3-CQIC) and focus on characterizing inner bounds. We design a new coding strategy based on (i) coset codes possessing algebraic closure properties and (ii) decoding POVMs to decode bi-variate interference efficiently. Needing to perform simultaneous decoding, we enhance Sen's powerful technique of tilting, smoothing, and augmentation - originally designed only for IID codes - to decode into `functions of codebooks'. Developing analysis techniques to combine all of these elements, we derive a new inner bound to the capacity region of a 3-CQIC. The derived inner bound subsumes all currently known inner bounds and is analytically proven to be strictly larger for identified examples, including non-commutative `additive' and `non-additive' ones.

DOI
10.1109/isit62367.2026.11653962

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