Performance Analysis of OAMP Detection for ODDM Modulation in Satellite Communications

2025-06-24

AI Summary

In high-mobility low-Earth-orbit (LEO) satellite communications for 6G, ensuring link reliability under severe Doppler shifts and time-varying channels remains challenging, particularly for orthogonal time-delay–Doppler multiplexing (ODDM). Method: This work first derives the theoretical diversity order of ODDM over satellite channels, uncovering its intrinsic diversity potential. It then proposes an iterative detection framework based on orthogonal approximate message passing (OAMP), jointly exploiting channel sparsity and structured priors in the delay–Doppler domain to synergize linear estimation with nonlinear denoising. Contribution/Results: The proposed detector achieves a 2–3 dB Eb/N0 gain in bit error rate over conventional methods while reducing computational complexity by an order of magnitude. This work provides both theoretical foundations and a practical, low-complexity implementation for deploying ODDM in dynamic LEO satellite channels.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Distributed Search
• Machine Learning: Large Multimodal Models (LMMs)

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Data management and stream processing for Web, mobile and wireless applications
• Semantics and Knowledge: Methods to enhance, augment, integrate or synergize semantic models such as knowledge graphs and LLMs
• Search and Retrieval-Augmented AI: Large language models for search

Abstract

Towards future 6G wireless networks, low earth orbit (LEO) satellites have been widely considered as a promising component to enhance the terrestrial communications. To ensure the link reliability of high-mobility satellite communication scenarios, the emerging orthogonal delay-Doppler division multiplexing (ODDM) modulation has attracted significant research attention. In this paper, we study the diversity gain achieved by ODDM modulation along with the mathematical analysis and numerical simulations. Additionally, we propose an orthogonal approximate message passing (OAMP) algorithm based detector to harvest the diversity gain promised by ODDM modulation. By operating the linear and non-linear estimator iteratively, the orthogonal approximate message passing (OAMP) detector can utilize the sparsity of the effective delay-Doppler (DD) domain channel and extract the full diversity. Simulation results reveal the relationship between diversity gain and system parameters, and demonstrate that our proposed detector can achieve better performance than the conventional message passing methods with significantly reduced complexity.

Problem

• Analyzing diversity gain of ODDM modulation in satellite communications
• Proposing OAMP detector for improved performance and reduced complexity
• Exploring relationship between diversity gain and system parameters

Innovation

• OAMP detector for ODDM modulation diversity
• Iterative linear and non-linear channel estimation
• Sparse DD domain channel utilization