# Physics-Aware Initialization Refinement in Code-Aided EM for Blind Channel Estimation

arXiv: https://arxiv.org/abs/2504.11241 · HTML: https://mlsanity.com/paper/2504.11241/

## Key facts

- Cited by 1 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 15 Apr 2025.

## Built on by (most cited first, 1 of 1)

- [Phase-Aware Code-Aided EM Algorithm for Blind Channel Estimation in PSK-Modulated OFDM](https://mlsanity.com/paper/2511.21340/) (2025)

## Abstract (arXiv)

This paper addresses the well-known local maximum problem of the expectation-maximization (EM) algorithm in blind intersymbol interference (ISI) channel estimation. This problem primarily results from phase and shift ambiguity during initialization, which blind estimation is inherently unable to distinguish. We propose an effective initialization refinement algorithm that utilizes the decoder output as a model selection metric, incorporating a technique to detect phase and shift ambiguity. Our results show that the proposed algorithm significantly reduces the number of local maximum cases to nearly one-third for a 3-tap ISI channel under highly uncertain initial conditions. The improvement becomes more pronounced as initial errors increase and the channel memory grows. When used in a turbo equalizer, the proposed algorithm is required only in the first turbo iteration, which limits any complexity increase with subsequent iterations.