Galaxy Codes: Advancing Achievability for Deterministic Identification via Gaussian Channels
Holger Boche, Christian Deppe, Safieh Mahmoodi, Golamreza Omidi
TL;DR
The paper tackles deterministic identification over Gaussian channels with power constraints and introduces Galaxy codes, a fractal, multi-level scheme that leverages hierarchical projections on hyperspheres. By combining spherical codes with a depth-structured galaxy construction and careful projection-based decoding, it proves a new achievable DI rate of at least $\tfrac{3}{8}$ on the $L(n,R)=2^{nR\log n}$ scale, improving the prior $\tfrac{1}{4}$ bound. The analysis establishes both codeword separation and vanishing error probabilities (Types I and II) through detailed packing arguments and Gaussian tail bounds. This advance narrows the gap toward the true DI capacity and demonstrates the potential of geometry-inspired, hierarchical coding for deterministic message identification in continuous-channel settings.
Abstract
Deterministic identification offers an efficient solution for scenarios where decoding entire messages is unnecessary. It is commonly used in alarm systems and control systems. A key advantage of this approach is that the capacity for deterministic identification in Gaussian channels with power constraints grows superexponentially, unlike Shannon's transmission capacity. This allows for a significantly higher number of messages to be transmitted using this event-driven method. So far, only upper and lower bounds for deterministic identification capacity have been established. Our work introduces a novel construction: galaxy codes for deterministic identification. Using these codes, we demonstrate an improvement in the achievability bound of 1/4 to 3/8, representing a previously unknown advance that opens new possibilities for efficient communication.
