arXiv subjects

Bingli Jiao

Publications and source records attributed to Bingli Jiao.

At least 19 recordsLinked to original sources

arXiv2026

Pinching-Antenna System With Movable Waveguides: Modeling and Optimization

This paper proposes a movable waveguide (MW)-enabled pinching-antenna system (PASS), in which each waveguide is connected via a flexible cable and can be linearly moved by drivers. By simultaneously moving the MWs and the pinching antennas (PAs) on them, MW-enabled PASS can effectively track user locations and form flexible array geometries for efficient beamforming. We first examine the special case with a single user and derive the closed-form solutions for the optimal MW positions as well as an upper bound on the user rate. Furthermore, we develop a two-step optimization algorithm to maximize the achievable rate for the user, where the first step determines the optimal MW positions using the derived closed-form solutions, and the second step alternately optimizes the PA positions through a one-dimensional (1D) local search based on the user location. Then, for the general multi-user scenario, we derive the upper bounds on the minimum rate among all users. To maximize their minimum rate, we propose a low-complexity two-scale optimization algorithm, where the large-scale global search coarsely determines the MW and PA positions, followed by a small-scale local search to finely tune them. In addition, a two-timescale optimization scheme based on statistical channel information is investigated to reduce the mechanical movement overhead of the MWs. Simulation results demonstrate that the proposed scheme achieves performance close to the derived bounds. It also flexibly adapts to different user distributions compared with the conventional PASS employing dense or sparse fixed-position waveguides (FPWs), as well as fixed-position antenna (FPA) schemes.

eess.SP↗

arXiv2026

Polarforming for Wireless Communications: Modeling and Performance Analysis

This paper presents, for the first time, the concept of polarforming for wireless communications. Polarforming refers to a novel technique that enables the polarization of an antenna to shape into a desired polarization state for aligning with the polarization of an electromagnetic (EM) wave. It can fully leverage polarization diversity to enhance the performance of wireless communication systems through polarization matching. To implement polarforming, we propose a new paradigm of phase shifter (PS)-based polarization-reconfigurable antennas (PRAs) that can form linear, circular, and general elliptical polarizations by phase shift control. To further demonstrate the benefits of polarforming, we investigate a PRA-aided wireless communication system equipped with tunable polarization of antennas. We characterize the multiple-input multiple-output (MIMO) channel capacity of the considered system as a function of the phase shifts of PS-based PRAs. We also provide a detailed polarforming interpretation under the single-input single-output (SISO) scenario and theoretically show how polarforming differs from the conventional (analog) beamforming based on PSs. Moreover, we develop an alternating optimization approach to maximize the channel capacity for the systems with single-antenna transmitter/receiver. Based on the water-filling principle, we also derive an upper bound on the MIMO channel capacity with PS-based PRAs and then maximize this capacity bound by optimizing the phase shifts through alternating optimization. Finally, comprehensive simulation results are presented, which not only validate the effectiveness of polarforming in combating channel depolarization but also exhibit substantial performance improvements over conventional systems.

eess.SP↗

arXiv2025

Secure Wireless Communication via Polarforming

Polarforming is a promising technique that enables dynamic adjustment of antenna polarization to mitigate depolarization effects commonly encountered during electromagnetic (EM) wave propagation. In this letter, we investigate the polarforming design for secure wireless communication systems, where the base station (BS) is equipped with polarization-reconfigurable antennas (PRAs) and can flexibly adjust the antenna polarization to transmit confidential information to a legitimate user in the presence of an eavesdropper. To maximize the achievable secrecy rate, we propose an efficient iterative algorithm to jointly optimize transmit beamforming and polarforming, where beamforming exploits spatial degrees of freedom (DoFs) to steer the transmit beam toward the user, while polarforming leverages polarization DoFs to align the polarization state of the EM wave received by the user with that of its antenna. Simulation results demonstrate that, compared to conventional fixed-polarization antenna (FPA) systems, polarforming can fully exploit the DoFs in antenna polarization optimization to significantly enhance the security performance of wireless communication systems.

cs.IT↗

arXiv2025

Energy Efficiency Maximization for Movable Antenna Communication Systems

This paper investigates energy efficiency maximization for movable antenna (MA)-aided multi-user uplink communication systems by considering the time delay and energy consumption incurred by practical antenna movement. We first examine the special case with a single user and propose an optimization algorithm based on the one-dimensional (1D) exhaustive search to maximize the user's energy efficiency. Moreover, we derive an upper bound on the energy efficiency and analyze the conditions required to achieve this performance bound under different numbers of channel paths. Then, for the general multi-user scenario, we propose an iterative algorithm to fairly maximize the minimum energy efficiency among all users. Simulation results demonstrate the effectiveness of the proposed scheme in improving energy efficiency compared to existing MA schemes that do not account for movement-related costs, as well as the conventional fixed-position antenna (FPA) scheme. In addition, the results show the robustness of the proposed scheme to imperfect channel state information (CSI) and provide valuable insights for practical system deployment.

cs.IT↗

arXiv2025

Linear Superposition Effect at Sources and in Waves

The superposition law (SL) sums the components of electromagnetic (EM) waves at each spatial point when these waves meet in space. In contrast, the energy conservation law requires energy to be summed in the quadratic form of the EM fields. The mathematical discrepancy of the two laws can lead to different physical results. Specifically, when two co-phase radiation dipoles are placed in close proximity, their radiation waves undergo a co-phase interference throughout space, therefore causing a net increase in wave's power globally. In the exploration of this, we find that the SL applies not only to waves, but also to the radiation dipoles. By defining the superposed dipole conceptually, we describe the effective radiation power that is twice the power-sum of the two waves, providing a comprehensive understanding of the SL, which is supported by the results of the previous theoretical and experimental studies.

physics.gen-ph↗

arXiv2025

Energy Efficiency Optimization for Movable Antenna-Aided Communication Systems

This paper investigates the energy efficiency optimization for movable antenna (MA) systems by considering the time delay and energy consumption introduced by MA movement. We first derive the upper bound on energy efficiency for a single-user downlink communication system, where the user is equipped with a single MA. Then, the energy efficiency maximization problem is formulated to optimize the MA position, and an efficient algorithm based on successive convex approximation is proposed to solve this non-convex optimization problem. Simulation results show that, despite the overhead caused by MA movement, the MA system can still improve the energy efficiency compared to the conventional fixed-position antenna (FPA) system.

cs.IT↗

arXiv2025

Movable Antenna-Aided Near-Field Integrated Sensing and Communication

Integrated sensing and communication (ISAC) is emerging as a pivotal technology for next-generation wireless networks. However, existing ISAC systems are based on fixed-position antennas (FPAs), which inevitably incur a loss in performance when balancing the trade-off between sensing and communication. Movable antenna (MA) technology offers promising potential to enhance ISAC performance by enabling flexible antenna movement. Nevertheless, exploiting more spatial channel variations requires larger antenna moving regions, which may invalidate the conventional far-field assumption for channels between transceivers. Therefore, this paper utilizes the MA to enhance sensing and communication capabilities in near-field ISAC systems, where a full-duplex base station (BS) is equipped with multiple transmit and receive MAs movable in large-size regions to simultaneously sense multiple targets and serve multiple uplink (UL) and downlink (DL) users for communication. We aim to maximize the weighted sum of sensing and communication rates (WSR) by jointly designing the transmit beamformers, sensing signal covariance matrices, receive beamformers, and MA positions at the BS, as well as the UL power allocation. The resulting optimization problem is challenging to solve. Thus, we propose an efficient two-layer random position (RP) algorithm to tackle it. In addition, to reduce movement delay and cost, we design an antenna position matching (APM) algorithm based on the greedy strategy to minimize the total MA movement distance. Extensive simulation results demonstrate the substantial performance improvement achieved by deploying MAs in near-field ISAC systems. Moreover, the results show the effectiveness of the proposed APM algorithm in reducing the antenna movement distance, which is helpful for energy saving and time overhead reduction for MA-aided near-field ISAC systems with large moving regions.

cs.IT↗

arXiv2025

Polarforming for Wireless Networks: Opportunities and Challenges

Polarforming emerges as a promising technique for manipulating the polarization of electromagnetic (EM) waves by shaping the polarization of an antenna into a desired state. By dynamically adjusting antenna polarization, polarforming enables real-time polarization matching or mismatching with received EM waves, thereby leveraging polarization degrees of freedom (DoFs) to enhance wireless communication performance. In this article, we first present an overview of the fundamental principles and design approaches underlying the polarforming technique. We then analyze the key advantages of polarforming, including hardware cost reduction, depolarization mitigation, channel adaptation, signal power enhancement, and interference suppression. Furthermore, we explore promising applications of polarforming for next-generation wireless networks. Numerical case studies demonstrate the substantial performance gains of polarforming over conventional fixed-polarization antenna (FPA) systems, along with a discussion of implementation challenges to motivate future research.

cs.IT↗

arXiv2025

Challenging the Law of Energy Conservation Through Superposed Waves Based on Spatial Symmetry of Two RF Sources: Theoretical Derivation and Experimental Verification

This study is grounded in the concept of spatial symmetry, which allows two co-phase RF sources to jointly radiate harmonic electromagnetic (EM) waves, even in presence of electromagnetic couplings between them. The superposition law is directly applied to the two waves owing to their sources, including the EM coupling effects. Our research uncovers a conflict with energy conservation law at the following two levels: (1) the total radiative powers as defined by Poynting theorem, and (2) further, the input powers of the sources. To explore this phenomenon, we create a symmetric dipole model to examine the energy behaviors at the sources and the superposed waves, separately. Both of the results reveal that the energy-doubling phenomenon presents when the dipoles are placed in close proximity. As the distance between the two dipoles increases, it is found that the total radiative power fluctuates in a damped manner and ultimately converges to a value required by energy conservation law. The theoretical conclusion of energy doubling is validated by experimental observations, which show a 1.59-fold increase in power within a microwave anechoic chamber. By analyzing the interactions, i.e., the EM coupling, between the two sources, we characterize a complete phenomenon of energy non-conservation.

physics.class-ph↗

arXiv2024

Movable Antenna-Aided Secure Full-Duplex Multi-User Communications

In this paper, we investigate physical layer security (PLS) for full-duplex (FD) multi-user systems. We consider a base station (BS) that operates in FD mode and transmits artificial noise (AN) to simultaneously protect uplink (UL) and downlink (DL) transmissions. Conventional fixed-position antennas (FPAs) at the FD BS struggle to fully exploit spatial degrees of freedom (DoFs) to improve signal reception and suppress interference. To overcome this limitation, we propose a novel FD BS architecture equipped with multiple transmit and receive movable antennas (MAs). The MAs introduce the DoFs in antenna position optimization, which can improve the performance of secure communication systems. To serve users and counter the cooperative interception of multiple eavesdroppers (Eves), we formulate a sum of secrecy rates (SSR) maximization problem to jointly optimize the MA positions, the transmit, receive, and AN beamformers at the BS, and the UL powers. We propose an alternating optimization (AO) algorithm, which decomposes the original problem into three sub-problems, to solve the challenging non-convex optimization problem with highly coupled variables. Specifically, we propose the multi-velocity particle swarm optimization (MVPSO), which is an improved version of the standard particle swarm optimization (PSO), to simultaneously optimize all MA positions. The transmit/AN beamformers and the UL powers are solved by successive convex approximation (SCA). The optimal receive beamformer is derived as a closed-form solution. Simulation results demonstrate the effectiveness of the proposed algorithms and the advantages of MAs over conventional FPAs in enhancing the security of FD multi-user systems.

eess.SP↗

arXiv2024

Power-Efficient Full-Duplex Satellite Communications Aided by Movable Antennas

This letter investigates a movable antenna (MA)-aided full-duplex (FD) satellite communication system, where the satellite, equipped with both transmit and receive MAs, serves multiple uplink (UL) and downlink (DL) user terminals (UTs) in FD mode. Specifically, we formulate a multiobjective optimization problem to minimize the UL and DL transmit powers under imperfect channel state information (CSI). To jointly optimize the MA positions and transmit powers, we propose a two-loop particle swarm optimization (PSO) algorithm based on a multiobjective optimization framework. Simulation results show that flexible adjustments of MA positions can effectively reduce the total UL and DL transmit powers, while also alleviating the burden on self-interference (SI) cancellation modules.

eess.SP↗

arXiv2024

Near-Field Multiuser Communications Aided by Movable Antennas

This letter investigates movable antenna (MA)-aided downlink (DL) multiuser communication systems under the near-field channel condition, where both the base station (BS) and the users are equipped with MAs to fully exploit the degrees of freedom (DoFs) in antenna position optimization. We develop a general channel model to accurately describe the channel characteristics in the near-field region and formulate an MA-position optimization problem to minimize the BS's transmit power subject to users' individual rate constraints. To solve this problem, we propose a two-loop dynamic neighborhood pruning particle swarm optimization (DNPPSO) algorithm that significantly reduces the computational complexity as compared to the standard particle swarm optimization (PSO) algorithm while achieving similar performance. Simulation results validate the effectiveness and advantages of the proposed scheme in power-saving for near-field multiuser communications.

eess.SP↗

arXiv2024

Prototype of Secure Wire-Line Telephone

This paper presents a secure wire-line telephone system that employs physical layer security (PLS) to protect against wiretapping. The system generates artificial noise (AN) in both transmission directions and uses a telephone hybrid circuit to effectively suppress the AN for the purpose of secure communication. Furthermore, we analyze the secrecy capacity of the system and evaluate its performance through theoretical analysis and practical experiments. The results demonstrate that the proposed system can significantly enhance communication security while preserving the integrity of legitimate signals. The results also validate that the proposed system is a robust and effective solution for securing wire-line telephone communications.

eess.SP↗

arXiv2024

Secure Full-Duplex Communication via Movable Antennas

This paper investigates physical layer security (PLS) in a movable antenna (MA)-assisted full-duplex (FD) system. In this system, an FD base station (BS) with multiple MAs for transmission and reception provides services for an uplink (UL) user and a downlink (DL) user. Each user operates in half-duplex (HD) mode and is equipped with a single fixed-position antenna (FPA), in the presence of a single-FPA eavesdropper (Eve). To ensure secure communication, artificial noise (AN) is transmitted to obstruct the interception of Eve. The objective of this paper is to maximize the sum secrecy rate (SSR) of the UL and DL users by jointly optimizing the beamformers of the BS and the positions of MAs. This paper also proposes an alternating optimization (AO) method to address the non-convex problem, which decomposes the optimization problem into three subproblems and solves them iteratively. Simulation results demonstrate a significant performance gain in the SSR achieved by the proposed scheme compared to the benchmark schemes.

cs.IT↗

arXiv2024

Movable Antenna-Enabled Co-Frequency Co-Time Full-Duplex Wireless Communication

Movable antenna (MA) provides an innovative way to arrange antennas that can contribute to improved signal quality and more effective interference management. This technology is especially beneficial for co-frequency co-time full-duplex (CCFD) wireless communication, which struggles with self-interference (SI) that usually overpowers the desired incoming signals. By dynamically repositioning transmit/receive antennas, we can mitigate the SI and enhance the reception of incoming signals. Thus, this paper proposes a novel MA-enabled point-to-point CCFD system and formulates the minimum achievable rate of two CCFD terminals. To maximize the minimum achievable rate and determine the positions of MAs, we introduce a solution based on projected particle swarm optimization (PPSO), which can circumvent common suboptimal positioning issues. Moreover, simulation results reveal that the PPSO method leads to better performance compared to the conventional alternating position optimization (APO). The results also demonstrate that an MA-enabled CCFD system outperforms the one using fixed-position antennas (FPAs).

cs.IT↗

arXiv2024

Auxiliary Factor Method to Remove ISI of Nyquist Filters

As has been known, the Nyquist first condition promises no intersymbol interference (ISI) as derived in the frequency domain. However, the practical implementation using the FIR filter truncates the Fourier transform by its window and prevents the mathematical calculation from reaching the ideal solution at zero-ISI. For obtaining better results, an increase in the window's length is required in general. To address this problem, a new approach is presented by using auxiliary factors (AFs) to compensate shortcomings of the truncated Fourier transform and remove the ISI completely, regardless of the window's length. In addition, the performance in the presence of the timing jitter is also improved significantly. The closed-form solution of the AFs is derived and the effectiveness is confirmed by the simulation results. Finally, the problems of the transmission delay and additional calculation complexity are analysed.

eess.SP↗

arXiv2023

A Contradiction to the Law of Energy Conservation by Waves Interference in Symmetric/Asymmetric mode

It can be agreed that the linear superposition and energy conservation are two independent physics laws in general. The former allows the energy to be re-distributed over space and the latter restricts the energy in the total amount. However, Levine shows the contradiction of the two laws mentioned above by creating a cleaver model that demonstrates the energy "doubling"- and "missing" phenomenon with the constrictive- and destructive interference at every point of whole space, respectively. While, he presented a wrong explanation by using one of the radiating sources to compare with an isolated source by the compensation of the impedance, where the mistake is simply analyzed in this paper. By setting up a spatial symmetric- and asymmetric-mode, we work upon Poynting theorem from the sources to the waves with the considerations of the superposition. The theoretical results reveal the invalidity of the energy conservation. Moreover, the experiments performed in the microwave anechoic chamber confirm the theoretical conclusion.

physics.gen-ph↗

arXiv2023

High-Precision Channel Estimation for Sub-Noise Self-Interference Cancellation

Self-interference cancellation plays a crucial role in achieving reliable full-duplex communications. In general, it is essential to cancel the self-interference signal below the thermal noise level, which necessitates accurate reconstruction of the self-interference signal. In this paper, we propose a high-precision channel estimation method specifically designed for sub-noise self-interference cancellation. Exploiting the fact that all transmitted symbols are known to their respective receivers, our method utilizes all transmitted symbols for self-interference channel estimation. Through analytical derivations and numerical simulations, we validate the effectiveness of the proposed method. The results demonstrate the superior performance of our approach in achieving sub-noise self-interference cancellation.

eess.SP↗