The development of sixth-generation (6G) terahertz (THz) wireless systems requires equalization techniques that can effectively handle severe channel impairments while maintaining low computational complexity. In this work, we propose a hybrid equalization framework that fuses regularized zero-forcing (ZF) with maximum likelihood (ML) refinement for ultra-massive multiple-input multiple-output (UM-MIMO) systems. The proposed Regularized ZF and ML Fusion (RZF-ML) equalizer leverages a regularization factor to mitigate noise enhancement and ill-conditioned channel effects, followed by a lightweight ML-based candidate search that refines symbol detection. This design provides a trade-off between the simplicity of linear equalizers and the optimality of ML detection. Simulation results under Rayleigh and Rician fading channels with high-order quadrature amplitude modulation (QAM) demonstrate that the RZF-ML equalizer achieves significantly improved bit error rate (BER) performance compared to conventional ZF and minimum mean square error (MMSE) equalizers, while approaching ML detection accuracy at a fraction of its complexity. The findings suggest that the proposed method is a promising candidate for robust equalization in 6G THz UM-MIMO networks, enabling reliable high-capacity communication in challenging propagation environments.

Tin-based perovskites are among the most promising candidates for high performance light-weight and radiation-tolerant space photovoltaics, but their response to energetic proton fluxes is not adequately determined. In this work, integrated SCAPS–SRIM analysis was applied to lead-free MASnI₃ perovskite solar cells for space applications in order to correlate device optimization with proton-radiation response. We established a combined SCAPS–SRIM simulation platform to simulate optoelectronic behaviors and radiation tolerance of an Au/Cu₂O/MASnI₃/TiO₂/FTO solar cell under AM0 illumination. Optimal-device calculations demonstrate that device absorber thickness of 0.20–0.30 µm and a TiO₂ ETL of 20–50 nm, Cu₂O HTL of 50 nm thicknesses result in good carrier collection and minimized recombination losses. Quantum efficiency and J–V measurement illustrate a stable operation under AM0 light, verifying the no extrinsic spectral incompatibility of MASnI₃ for the space energy source application. SRIM proton irradiation simulations (10-250 keV, 0° incidence) highlight the most damaging energy range within 50–150 keV for which masked Bragg peak lies in proximity to the MASnI₃ absorber and MASnI₃/TiO₂ interface accompanied by enhanced vacancy density, recoil energy deposition and phonon generation. High-energy protons (>200 keV) which deposit most of their damage in the rear contact stack, minimizing absorber degradation. The results overall indicate that MASnI₃ holds a good optoelectronic performance beyond the predictable radiation-damage behavior and thus can be considered as a promising alternative for space photovoltaic technology

The aim of this research is to comparatively evaluate and optimize the performance of active and passive Reconfigurable Intelligent Surfaces (RIS) in Terahertz (THz) Ultra Massive MIMO(UM-MIMO) systems for 6G Wireless Communication. The Primary objective is to analyze the impact of beamforming and adaptive modulation schemes on system capacity, computational complexity and power consumption. The study employs MATLAB based simulations under realistic wireless channel models including Rician fading channel and free space path loss to model the propagation behavior at THz Frequencies. Both active and passive RIS configuration are assessed using hybrid beamforming and multi antenna transmission techniques. Simulation results demonstrate that active RIS improves system capacity compared to passive RIS. Particularly at higher SNR level, while incurring more power consumption. Conversely, passive RIS offers better energy efficiency and lower complexity, making it suitable for low-power scenarios. These findings highlight critical design trade-offs and support the development of hybrid RIS assisted UM-MIMO architectures for efficient and scalable 6G THz communication systems.  

This paper explores the potential of Ultra-Massive Multiple Input Multiple Output (UM MIMO) systems as a key technology for 6G wireless communications within the Terahertz (THz) frequency band (0.1 – 10 THz). The THz spectrum offers immense capacity and speed advantages but presents significant challenges, such as higher propagation losses and limited coverage range due to atmospheric absorption and signals spreading. The study provides a comprehensive analysis of UM MIMO’s technical performance in overcoming these challenges, focusing on key metrics such as signal propagation, system capacity, and coverage range. Additionally, the research examines the optimization of beam dynamics and spectral efficiency in UM MIMO systems under various wireless channel conditions and precoding techniques. The findings highlight the importance of advanced antenna techniques and adaptive beam management in maximizing the efficiency and viability of 6G THz networks, positioning UM MIMO as a fundamental solution for next-generation wireless communication.