Parallel Coding for Orthogonal Delay-Doppler Division Multiplexing
Qi Li, Jinhong Yuan, Min Qiu
TL;DR
This work addresses Doppler-induced challenges in 2D delay-Doppler modulation by introducing a parallel channel encoding (PCE) scheme for ODDM and an iterative, tightly-coupled detection/decoding framework with successive decoding feedback (SDF). By encoding each delay-Doppler row with independent short codewords, the receiver exchanges soft information with the detector on a per-row basis, enabling faster convergence and reduced complexity compared to a conventional single long-codeword approach. The authors develop soft interference cancellation based SIC-MMSE detection, perform density evolution and finite-blocklength analyses, and demonstrate via simulations that PCE-SDF outperforms SCE-PDF by up to about 1 dB with significantly lower complexity. The proposed approach offers a practical path to higher reliability in high-mobility channels and can be extended to CP-ODDM, highlighting the benefits of joint detector-decoder design in DD-domain modulations.
Abstract
This paper proposes a novel parallel coding transmission strategy and an iterative detection and decoding receiver signal processing technique for orthogonal delay-Doppler division multiplexing (ODDM) modulation. Specifically, the proposed approach employs a parallel channel encoding (PCE) scheme that consists of multiple short-length codewords for each delay-Doppler multicarrier (DDMC) symbol. Building upon such a PCE transmission framework, we then introduce an iterative detection and decoding algorithm incorporating a successive decoding feedback (SDF) technique, which enables instant information exchange between the detector and decoder for each DDMC symbol. To characterize the error performance of the proposed scheme, we perform density evolution analysis considering the finite blocklength effects. Our analysis results, coupled with extensive simulations, demonstrate that the proposed PCE scheme with the SDF algorithm not only showcases a better overall performance but also requires much less decoding complexity to implement, compared to the conventional benchmark scheme that relies on a single long channel code for coding the entire ODDM frame.
