Approximate Soft Successive Detection for Grassmannian Product Superposition Coding

Abstract

We consider non-coherent single-input multiple-output transmission using a previously proposed Grassmannian product superposition constellation. We develop a novel soft successive detection (SSD) for this structure, which allows to effectively combine the considered product symbol constellation with available forward error correction channel coding schemes that support soft decoding. We derive bit-level log-likelihood ratios (LLRs) for SSD and propose three approaches for successive approximate LLR computation of increasing accuracy and complexity. We demonstrate the performance of the proposed approach by numerical simulations.