Bit-Level Modeling and Reception Analysis of Concurrent Transmissions in Galvanic Coupled Communication

Abstract

Wireless body area networks (WBANs) based on galvanic coupled communication are a promising physical-layer paradigm for the next-generation smart healthcare systems. However, high-frequency, fine-grained data exchange among multiple nodes is prone to concurrent collisions, which can severely degrade system stability and sensing accuracy. To elucidate the physical-layer collision mechanism and quantify receiver performance limits, this work adopts a multilayer human channel model as an enabling foundation to establish a bit-level concurrent transmission analysis system for galvanic coupled communication. This framework integrates the human body channel, asynchronous interferers, and differential correlation detection to formulate a quantitative mapping from the multidimensional concurrence parameter space to the conditional bit error rate (BER). Within this framework, capture boundaries are explicitly derived along the topology, carrier-frequency offset, and time/phase offset dimensions. The results show that successful reception is governed by structured capture regions rather than by a single signal-to-interference-ratio threshold. Furthermore, direct-sequence spread spectrum (DSSS) is shown to not only enhance interference resilience but also significantly shrink the effective interference radius, thereby enabling higher achievable capacity through spatial reuse. Validated by on-body channel measurements and benchtop software-defined radio (SDR) experiments, the predicted capture boundaries are confirmed on real galvanic coupled communication links. Overall, this work provides quantitative performance bounds and practical guidelines for protocol design and cross-layer optimization in body area networks based on galvanic coupled communication.