A Proximal Descent Approach for Low Complexity Detection in Uplink OTSM

Abstract

Orthogonal Time Sequency Multiplexing (OTSM) is a single-carrier modulation technique capable of transmitting high data rates effectively and reliably in fast-changing wireless channels. However, signal detection of OTSM is challenging due to the non-linear relationship between the time domain and the delay-sequency (DS) domain. This article presents a low-complexity proximal descent-based approach for robust signal detection in OTSM systems. The proposed approach iteratively detects the transmitted signal utilizing a hyperbolic tangent-based penalty. An extensive convergence analysis of the proposed detection approach is performed considering the existence of strong convexity and bounded subgradients of the regularized cost function. Analytically, it is shown that the proposed approach has a linear rate of convergence in expectation. The simulation results also indicate that the proposed detection approach significantly outperforms several conventional detection approaches for uplink OTSM systems. Furthermore, the proposed approach exhibits lower computational complexity in terms of floatingpoint operations over several conventional detection approaches for uplink OTSM, which are capable of achieving near-maximum likelihood performance. Hence, the proposed detection approach offers a low complexity and promising solution to achieve signal detection with reliability in OTSM systems, especially beyond 5G wireless communication systems. © 2025 IEEE.