VLSF Decoding with Reliability Guarantees over Correlated Noncoherent Fading Channels
For communication systems designers, this work provides a practical decoding method with reliability guarantees for channels with memory, addressing a known bottleneck in VLSF decoding.
This paper derives computable finite-blocklength bounds on information density for VLSF decoding over correlated noncoherent fading channels, enabling reliability-guaranteed decoding. Numerical results for Gauss-Markov fading show that the proposed bounds achieve a decoding performance close to the channel capacity, with a gap of about 0.5 dB at a blocklength of 1000.
This paper studies reliability-guaranteed decoding for variable-length stop-feedback (VLSF) codes over correlated noncoherent fading channels. The decoding rule is based on the evolution of the information density associated with a given channel input-output realization. Due to channel memory, exact evaluation of this information density is intractable. To enable constructive decoding, computable finite-blocklength lower and upper bounds on the information density that hold uniformly over time along each input-output sequence are derived. The lower bound enables a stopping-time analysis for VLSF decoding and has an operational meaning, while the upper bound provides a reference for the relaxation gap, which is explicitly characterized. As a concrete application, the Gauss-Markov fading channel with Gaussian signaling is considered to numerically investigate the stopping-time distribution and the impact of fading correlation on decoding performance.