{"ID":2852418,"CreatedAt":"2026-06-01T04:54:23.091178241Z","UpdatedAt":"2026-06-01T04:54:23.091178241Z","DeletedAt":null,"paper_url":"https://arxiv.org/abs/2510.19007","arxiv_id":"2510.19007","title":"Fundamental Limits of Cooperative Integrated Sensing and Communications over Low-Earth Orbit THz Satellite Channels","abstract":"Terahertz inter-satellite links enable unprecedented sensing precision for Low Earth Orbit (LEO) constellations, yet face fundamental bounds from hardware impairments, pointing errors, and network interference. We develop a Network Cramér-Rao Lower Bound (N-CRLB) framework incorporating dynamic topology, hardware quality factor $Γ_{\\text{eff}}$, phase noise $σ^2_φ$, and cooperative effects through recursive Fisher Information analysis. Our analysis reveals three key insights: (i) hardware and phase noise create power-independent performance ceilings ($σ_{\\text{ceiling}} \\propto \\sqrt{Γ_{\\text{eff}}}$) and floors ($σ_{\\text{floor}} \\propto \\sqrt{σ^2_φ}/f_c$), with power-only scaling saturating above $\\text{SNR}_{\\text{crit}}=1/Γ_{\\text{eff}}$; (ii) interference coefficients $α_{\\ell m}$ enable opportunistic sensing with demonstrated gains of 5.5~dB under specific conditions (65~dB processing gain, 50~dBi antennas); (iii) measurement correlations from shared timing references, when properly modeled, do not degrade performance and can provide common-mode rejection benefits compared to mismodeled independent-noise baselines. Sub-millimeter ranging requires co-optimized hardware ($Γ_{\\text{eff}}\u003c0.01$), oscillators ($σ^2_φ\u003c10^{-2}$), and appropriate 3D geometry configurations.","short_abstract":"Terahertz inter-satellite links enable unprecedented sensing precision for Low Earth Orbit (LEO) constellations, yet face fundamental bounds from hardware impairments, pointing errors, and network interference. We develop a Network Cramér-Rao Lower Bound (N-CRLB) framework incorporating dynamic topology, hardware quali...","url_abs":"https://arxiv.org/abs/2510.19007","url_pdf":"https://arxiv.org/pdf/2510.19007v1","authors":"[\"Haofan Dong\",\"Houtianfu Wang\",\"Hanlin Cai\",\"Ozgur B. Akan\"]","published":"2025-10-21T18:40:48Z","proceeding":"eess.SP","tasks":"[\"eess.SP\"]","methods":"[]","has_code":false}