Cooperative Multi-Sensor Detection under Variable-Length Coding

TL;DR

This paper introduces a variable-length coding scheme for cooperative multi-sensor detection that improves error exponents under rate constraints, outperforming fixed-length coding by a factor related to the type-I error limit.

Contribution

It proposes a novel variable-length coding approach for cooperative sensors that enhances detection performance compared to traditional fixed-length schemes.

Findings

Variable-length coding increases the achievable error exponent.

The optimal error exponent depends on the type-I error probability.

The scheme outperforms fixed-length coding by a factor of (1-ε)^{-1}.

Abstract

We investigate the testing-against-independence problem \mw{over a cooperative MAC} with two sensors and a single detector under an average rate constraint on the sensors-detector links. For this setup, we design a variable-length coding scheme that maximizes the achievable type-II error exponent when the type-I error probability is limited to $\epsilon$. Similarly to the single-link result, we show here that the optimal error exponent depends on $\epsilon$ and that variable-length coding allows to \mw{increase the rates over the optimal} fixed-length coding \mw{scheme} by the factor $(1-\epsilon)^{-1}$.