Spectrum Sharing by Space-Time Waveform Shaping

2025-04-08

AI Summary

To address the challenges of plug-and-play link deployment, weak interference avoidance, and poor coexistence robustness in spectrum-saturated environments, this paper proposes a spatiotemporal joint adaptive waveform shaping method. It establishes dynamic MIMO wireless links within occupied spectral bands by jointly optimizing transmit-side spatial–temporal beamforming weights and pulse coding sequences—minimizing per-bit-per-antenna transmit energy while satisfying receiver SINR constraints and strictly suppressing in-band interference to non-cooperative neighboring links. This work achieves, for the first time, autonomous interference avoidance and proactive protection without requiring additional spectrum allocation. Experimental results on a 4×4 reconfigurable MIMO system demonstrate that the proposed method improves pre-detection SINR by 8.2 dB and reduces adjacent-channel in-band power leakage by 12.6 dB compared to non-adaptive baselines, significantly enhancing spectral coexistence capability in dense wireless deployments.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Mixed Discrete/Continuous Search
• Cognitive Modeling & Cognitive Systems: Neural Spike Coding

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendation
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

In this paper, we consider the task of introducing a new wireless data link over a given occupied frequency band using a multi-antenna transmitter and receiver. We design formally a dynamic multiple-input multiple-output (MIMO) wireless link that can coexist in the fixed congested frequency band by (a) optimally avoiding sensed interference in the joint space-time domain, and (b) protecting existing links by minimizing its own transmitted power in the band. In particular, the transmit beam weight vector and time domain pulse code sequence are jointly optimized to minimize the transmit energy per bit per antenna, while maintaining a pre-defined signal-to-interference-plus-noise ratio (SINR) at the output of the joint space-time maximum SINR receiver filter. Extensive numerical studies are carried out to demonstrate the derived algorithmic solution in light and heavily congested band scenarios with non-cooperative co-channel links. We show that the proposed autonomously reconfigurable 4x4 MIMO link outperforms a non-adaptive transceiver and other forms of waveform shaping in terms of the pre-detection SINR performance and the capability to protect ongoing non-cooperative links by not occupying the band with redundant transmissions.

Problem

• Designing a dynamic MIMO link for shared frequency bands
• Optimizing space-time waveforms to minimize interference
• Enhancing SINR while protecting existing non-cooperative links

Innovation

• Dynamic MIMO link for spectrum sharing
• Joint space-time interference avoidance
• Optimized transmit power and beamforming