arXiv subjects

Xiaoming She

Publications and source records attributed to Xiaoming She.

3 recordsLinked to original sources

arXiv2026

Simultaneous Indoor and Outdoor Coverage with Conformal Intelligent Omni-Surface

Seamless indoor--outdoor coverage conventionally relies on coordinated outdoor macro cells and indoor small cells, incurring high deployment and backhaul costs. Intelligent omni-surfaces (IOSs) provide a promising alternative by enabling simultaneous reflection and transmission across building boundaries. Enabled by recent advances in conformal antennas, conformal IOSs (CIOSs) mounted on building facades offer a flexible and deployment-friendly solution for integrated indoor--outdoor coverage. This paper develops a stochastic-geometry framework to evaluate the downlink performance of CIOS-assisted networks serving both indoor and outdoor users. Specifically, a building-dependent spatial model is established where randomly located buildings are modeled via a Boolean scheme with CIOSs mounted on their facades. Unlike planar IOS deployment, conformal integration introduces geometry dependent visibility constraints, which are captured through the effective numbers of participating elements defined by visible arc metrics for reflection and transmission. Incorporating these constraints, coverage probability expressions are derived under three CIOS operating protocols. Numerical results show that, compared with planar IOS, CIOS improves the successful connection probabilities of the reflected and transmitted links by up to 75% and 125%, respectively, while the overall coverage gain remains dependent on blockage conditions because curvature reduces the effective serving aperture.

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arXiv2023

Enabling Secure Wireless Communications via Movable Antennas

A pioneering secure transmission scheme is proposed, which harnesses movable antennas (MAs) to optimize antenna positions for augmenting the physical layer security. Particularly, an MA-enabled secure wireless system is considered, where a multi-antenna transmitter communicates with a single-antenna receiver in the presence of an eavesdropper. The beamformer and antenna positions at the transmitter are jointly optimized under two criteria: power consumption minimization and secrecy rate maximization. For each scenario, a novel suboptimal algorithm was proposed to tackle the resulting nonconvex optimization problem, capitalizing on the approaches of alternating optimization and gradient descent. Numerical results demonstrate that the proposed MA systems significantly improve physical layer security compared to various benchmark schemes relying on conventional fixed-position antennas (FPAs).

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arXiv2023

Cramer-Rao Lower Bound Analysis for OTFS and OFDM Modulation Systems

The orthogonal time frequency space (OTFS) modulation as a promising signal representation attracts growingcinterest for integrated sensing and communication (ISAC), yet its merits over orthogonal frequency division multiplexing (OFDM) remain controversial. This paper devotes to a comprehensive comparison of OTFS and OFDM for sensing from the perspective of Cramer-Rao lower bounds (CRLB) analysis. To this end, we develop the cyclic prefix (CP)-Free and CP-added model for OFDM, while for OTFS, we consider the Zak transform based and the Two-Step conversion based models, respectively. Then we rephrase these four models into a unified matrix format to derive the CRLB of the delays and doppler shifts for multipath scenario. Numerical results demonstrate the superiority of OTFS modulation for sensing, and the effect of physical parameters for performance achievement.

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