Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2610.24641

Widely Linear-Enhanced IQ Imbalance Interference Cancellation for AFDM-FTN Systems

Xianle Dai·Bowei Xue·Qu Luo·Jianguo Li·Neng Ye·Kai Yang·Pei Xiao
View original source ↗Read source document ↗Export metadata ↓

Abstract

Internet of Things (IoT) networks require reliable and spectrally efficient wireless links to support massive device connectivity and high mobility applications. To meet these requirements, this paper investigates a widely linear (WL)-empowered receiver design for affine frequency division multiplexing (AFDM) with faster-than-Nyquist (FTN) signaling under practical receiver in phase and quadrature imbalance (IQI). The considered AFDM-FTN system couples the direct and image branches with FTN induced intersymbol interference (FTN-ISI) and delay-Doppler spreading in the affine domain. To address this coupled interference structure, a unified conjugate augmented input output model is established for IQI impaired AFDM-FTN systems. Based on this model, a WL minimum mean square error receiver with parallel interference cancellation (WL-MMSE-PIC) is developed, where WL-MMSE preprocessing is followed by the proposed hard decision PIC (HD-PIC) and damped soft decision PIC (SD-PIC). The proposed receiver is further analyzed in terms of the local stability of HD-PIC, a genie aided performance reference under ideal residual interference cancellation, and the impact of the AFDM chirp parameter on the post equalization interference distribution. Simulation results show that the proposed WL-MMSE-HD-PIC and WL-MMSE-SD-PIC receivers achieve significant error rate performance gains over the conventional linear-MMSE and WL-MMSE baselines. The results further show that FTN signaling provides a nominal spectral-efficiency gain, while residual-coupling-based chirp-parameter selection reduces the post-equalization residual coupling and improves detection reliability for high-mobility IoT links.

Explore related subjects

eess.SP

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Xianle Dai, Bowei Xue, Qu Luo, Jianguo Li, Neng Ye, Kai Yang, Pei Xiao. 2026-10-17. Widely Linear-Enhanced IQ Imbalance Interference Cancellation for AFDM-FTN Systems. https://arxiv.org/abs/2610.24641

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Curved HF Monopole Antennas for Improved Low-Angle Skywave Gain Over Lossy Ground

High-frequency (HF) skywave radars require high gain at elevation angles of 3 degrees to 30 degrees, where vertically-polarized monopoles over lossy land suffer from pseudo-Brewster cancellation. This letter shows that curving a long monopole creates a horizontally-polarized radiation channel much less affected by this cancellation. Closed-form bounds derived from the space-wave field over a homogeneous half-space show that the vertical-current field is suppressed below an elevation set by the soil permittivity, whereas the horizontally-polarized field of an elevated arc is nearly unaffected by the soil. Bayesian optimization (BO) of an analytical model, followed by 182 full-wave HFSS simulations with analytical Fresnel far-field post-processing, was used to design the element at 15 MHz. Over moist soil, a 15-m element with an 86 degrees arc is near-resonant (-25-dB match), 93% efficient, and 25% lower than a straight element of equal length. It raises the azimuth-averaged 3 degrees-30 degrees gain by 2.5 dB and, on every land ground considered, exceeds the 0.575λ straight monopole that is optimal over seawater and PEC by 1.0-2.6 dB.

eess.SP↗
arXiv2026

Movable Antenna-Enabled Multi-Static Cooperative Secure ISAC: Architecture, Mechanisms, and Enabling Technologies

The broadcast nature of integrated sensing and communication (ISAC) signals exposes them to physical-layer security (PLS) threats, including eavesdropping and jamming. Conventional fixed-position antennas provide limited spatial flexibility under highly correlated legitimate, sensing, and adversarial channels, while multi-static cooperative ISAC offers distributed spatial diversity but remains vulnerable to information leakage. To address these limitations, this article proposes a novel movable antenna (MA)-enabled multi-static cooperative secure ISAC framework centered on dual-scale spatial reconfiguration. Specifically, continuous MA repositioning reshapes local propagation channels, while distributed multi-static nodes provide complementary network-level spatial diversity. Their synergy transforms local antenna geometry and distributed network geometry into a unified controllable spatial resource for jointly enhancing communication, sensing, and PLS. This article first presents the system architecture of the proposed framework and its representative application scenarios, followed by an analysis of the physical-layer mechanisms underlying the resulting gains. Subsequently, we elaborate on the key enabling technologies for practical deployment. A case study further demonstrates the communication-sensing-security trade-off and antenna-saving potential of the proposed framework. Finally, open challenges and future research directions are identified toward practical MA-enabled multi-static secure ISAC networks.

eess.SP↗
arXiv2026

Dual Secure Sensing and Communications in MA-Enabled Networked ISAC Systems

Integrated sensing and communication (ISAC) is envisioned as a cornerstone technology for next-generation networks, yet it introduces significant security risks in both communication and sensing domains. To mitigate the coverage limitations inherent in conventional mono-static or bi-static setups, this paper proposes a networked ISAC framework empowered by movable antennas (MAs). By leveraging flexible antenna reconfiguration, MAs provide additional spatial degrees of freedom to significantly boost beamforming gain and interference suppression. Specifically, we investigate a novel dual-domain security paradigm where networked base stations collaboratively protect uplink (UL) and downlink (DL) transmissions from communication eavesdropping while simultaneously safeguarding target sensing data against sensing eavesdroppers (SEs). To this end, we formulate a joint optimization problem to maximize the sum of secrecy rates, subject to sensing requirements, SE eavesdropping probability constraint, and practical MA deployment constraints, by jointly optimizing receive combiners, transmit beamformers, UL power allocation, and MA positions. To address this non-convex problem with highly coupled variables, an efficient alternating optimization algorithm is proposed, integrating closed-form solutions for receive combiners, successive convex approximation for transmit beamforming and UL power, and a tailored sensing-aware multi-candidate particle swarm optimization for the high-dimensional MA positioning. Extensive numerical results validate the effectiveness of the proposed algorithms, demonstrating that the proposed MA-enabled networked cooperative ISAC design significantly outperforms conventional fixed-position antenna-based designs in terms of security performance, while achieving notable power- and antenna-saving gains.

eess.SP↗