{"ID":2899391,"CreatedAt":"2026-06-01T04:54:23.091178241Z","UpdatedAt":"2026-06-01T04:54:23.091178241Z","DeletedAt":null,"paper_url":"https://arxiv.org/abs/2507.02168","arxiv_id":"2507.02168","title":"Experimental Multiport-Network Parameter Estimation and Optimization for Multi-Bit RIS","abstract":"Physics-consistent theoretical studies on RIS-parametrized wireless channels use models from multiport-network theory (MNT) to capture mutual-coupling (MC) effects. However, in practice, RIS design and radio environment are partially or completely unknown. We fill a research gap on how to estimate the MNT model parameters in such experimentally relevant scenarios. Our technique efficiently combines closed-form and gradient-descent steps, and it can be applied to multi-bit-programmable RIS elements. We discuss inevitable (but operationally irrelevant) parameter ambiguities. We experimentally validate our technique in an unknown rich-scattering environment parametrized by eight 6-bit-programmable RIS elements of unknown design. We experimentally evaluate the performance of RIS configurations optimized with the estimated MNT model and an MC-unaware cascaded model. While the models differ in accuracy by up to 17 dB, the end-to-end performance differences are small.","short_abstract":"Physics-consistent theoretical studies on RIS-parametrized wireless channels use models from multiport-network theory (MNT) to capture mutual-coupling (MC) effects. However, in practice, RIS design and radio environment are partially or completely unknown. We fill a research gap on how to estimate the MNT model paramet...","url_abs":"https://arxiv.org/abs/2507.02168","url_pdf":"https://arxiv.org/pdf/2507.02168v2","authors":"[\"Philipp del Hougne\"]","published":"2025-07-02T21:48:54Z","proceeding":"physics.app-ph","tasks":"[\"physics.app-ph\",\"eess.SP\"]","methods":"[]","has_code":false}