Abstract
Wi-Fi channel state information (CSI) enables contactless presence detection and gesture recognition. Its high-dimensional complex-valued time series require input representations that preserve informative temporal variations during compression. We propose Trajectory-Guided Tokenization (TGT), which combines complex trajectory decomposition with asymmetric attention to construct compact continuous tokens. For each antenna link and subcarrier, an orthonormal Helmert transform decomposes short, ordered temporal patches into local-center and centered-trajectory coordinates. Keys are learned from the centered-trajectory coordinates, while values retain both components. Learnable queries aggregate subcarriers into frequency slots, which are fused into temporal tokens. Trained jointly from scratch, TGT with TokenMLP achieves the highest mean accuracy of 92.83% among all evaluated frontend-backend combinations on the self-collected dataset. Experiments on EHUNAM and Widar further support the applicability of TGT to cross-domain presence detection and gesture recognition.
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Cite this article
APA 7
Wang, Z., Xu, K., Jiang, J., Yang, Y., Chen, Z., Bai, X., Chen, M., Chen, X., He, J., Nielsen, J. H., & Schmid, S. (2026). Trajectory-Guided Tokenization of Complex CSI for Wi-Fi Sensing. https://omanscience.com/en/articles/trajectory-guided-tokenization-of-complex-csi-for-wi-fi-sensing
MLA 9
Wang, Ziyi, et al. "Trajectory-Guided Tokenization of Complex CSI for Wi-Fi Sensing." https://omanscience.com/en/articles/trajectory-guided-tokenization-of-complex-csi-for-wi-fi-sensing.
Chicago (author–date)
Wang, Ziyi, Kenuo Xu, Jichu Jiang, Yumeng Yang, Zheng Chen, Xiaofei Bai, Muge Chen, Xuyang Chen, Jinglei He, Jannik Hammel Nielsen, and Stefan Schmid. 2026. "Trajectory-Guided Tokenization of Complex CSI for Wi-Fi Sensing." https://omanscience.com/en/articles/trajectory-guided-tokenization-of-complex-csi-for-wi-fi-sensing.
Harvard
Wang, Z., Xu, K., Jiang, J., Yang, Y., Chen, Z., Bai, X., Chen, M., Chen, X., He, J., Nielsen, J. H. and Schmid, S. (2026) 'Trajectory-Guided Tokenization of Complex CSI for Wi-Fi Sensing', Available at: https://omanscience.com/en/articles/trajectory-guided-tokenization-of-complex-csi-for-wi-fi-sensing.
Vancouver
Wang Z, Xu K, Jiang J, Yang Y, Chen Z, Bai X, et al. Trajectory-Guided Tokenization of Complex CSI for Wi-Fi Sensing. https://omanscience.com/en/articles/trajectory-guided-tokenization-of-complex-csi-for-wi-fi-sensing
IEEE
Z. Wang, K. Xu, J. Jiang, Y. Yang, Z. Chen, X. Bai, M. Chen, X. Chen, J. He, J. H. Nielsen, and S. Schmid, "Trajectory-Guided Tokenization of Complex CSI for Wi-Fi Sensing," https://omanscience.com/en/articles/trajectory-guided-tokenization-of-complex-csi-for-wi-fi-sensing.