Semantic-Aware Co-Design of Spatio-Temporal Focusing and Adaptive Modulation for Wearable Brain-Body Neuro-Interfaces

This paper presents a communication-theoretic, semantic-aware co-design for a wearable brain-body neuro-interface that addresses the dynamic somatic dysregulation in Major Depressive Disorder. At the physical layer, we derive an analytical spatio-temporal focusing model for temporal interference (TI) stimulation using a multilayer spherical head formulation. Closed-form envelope metrics enable efficient optimization of focusing gain and mainlobe-to-sidelobe ratio (MSR) under scalp-current safety constraints, yielding a library of high-precision stimulation actions. At the MAC layer, wearable biosignals are abstracted into semantic channel state information, and adaptive modulation is cast as a Markov decision process with energy/safety-aware rewards; the optimal policy is obtained by value iteration. Analytical and simulation results show that the proposed co-design sustains high MSR at deep targets with phase-locked steering, improves long-term therapeutic reward versus static or myopic baselines, and shortens the time to a desired "Calm"state, with multiplicative benefits over isolated layer designs.