Joint Channel Estimation and Symbol Detection for Pilot-Free Superposition Transmissions Over Dynamic 3D Trellis

TY - JOUR

T1 - Joint Channel Estimation and Symbol Detection for Pilot-Free Superposition Transmissions Over Dynamic 3D Trellis

AU - Zhang, Yue

AU - Ye, Neng

AU - Ye, Shuxiao

AU - Ding, Xuhui

AU - Yang, Kai

AU - An, Jianping

N1 - Publisher Copyright: © 1967-2012 IEEE.

PY - 2026/5/1

Y1 - 2026/5/1

N2 - Superposition transmissions can simultaneously accommodate multiple users, while incorporating pilot-free design can further reduce the signaling overhead. Achieving reliable communication for pilot-free superposition transmissions faces previously unaddressed challenges not only due to unignorable inter-user interference (IUI) but also to unknown channel state information (CSI). Considering such difficulties, we first propose a dynamic 3D trellis diagram to effectively characterize the pilot-free superimposed signals, where IUI is introduced as an additional dimension, and a notion of updatable path metric is proposed to adapt to instantaneous CSI estimation. An interference-aware forward-backward Viterbi algorithm is then proposed for pilot-free joint channel estimation and symbol detection, with forward path selection using Gaussian mixture model-based piecewise metric calculation and backward CSI update using survivor path metric maximization. Interference reconstruction and cancellation are further developed for iterative interference suppression among users. The convergence of the proposed algorithm is also theoretically proved. Simulation results indicate that our method achieves an order-of-magnitude frame error rate improvement over state-of-the-art methods.

AB - Superposition transmissions can simultaneously accommodate multiple users, while incorporating pilot-free design can further reduce the signaling overhead. Achieving reliable communication for pilot-free superposition transmissions faces previously unaddressed challenges not only due to unignorable inter-user interference (IUI) but also to unknown channel state information (CSI). Considering such difficulties, we first propose a dynamic 3D trellis diagram to effectively characterize the pilot-free superimposed signals, where IUI is introduced as an additional dimension, and a notion of updatable path metric is proposed to adapt to instantaneous CSI estimation. An interference-aware forward-backward Viterbi algorithm is then proposed for pilot-free joint channel estimation and symbol detection, with forward path selection using Gaussian mixture model-based piecewise metric calculation and backward CSI update using survivor path metric maximization. Interference reconstruction and cancellation are further developed for iterative interference suppression among users. The convergence of the proposed algorithm is also theoretically proved. Simulation results indicate that our method achieves an order-of-magnitude frame error rate improvement over state-of-the-art methods.

KW - Superposition transmissions

KW - joint channel estimation and symbol detection

KW - pilot-free

KW - trellis diagram

UR - https://www.scopus.com/pages/publications/105021104435

U2 - 10.1109/TVT.2025.3629849

DO - 10.1109/TVT.2025.3629849

M3 - Article

AN - SCOPUS:105021104435

SN - 0018-9545

VL - 75

SP - 8605

EP - 8610

JO - IEEE Transactions on Vehicular Technology

JF - IEEE Transactions on Vehicular Technology

IS - 5

ER -