Blind Multiuser Detection in Asynchronous Variable processing gain in spread spectrum IoT systems

Document Type : Research Article

Author

Faculty of Engineering Technology, Amol University of Special Modern Technologies, Amol, Iran

10.22080/frai.2025.5663

Abstract

In the context of rapidly expanding Internet of Things (Io T) deployments, ensuring reliable detection and decoding of low-power, wideband signals from numerous asynchronous devices is a critical challenge. This paper presents a novel blind multiuser detection technique for Variable Processing Gain Direct-Sequence CDMA (VPG-DS/CDMA) tailored to Io T networks. Building on prior fluctuation-based autocorrelation estimators, our method removes all constraints on individual spreading gains and operates effectively in multipath fading channels. By dynamically adjusting each device’s spreading length, we demonstrate both an amplified periodic fluctuation signature and a direct relationship between fluctuation peak amplitude and spreading factor, enabling robust user separation even when signals are buried below the noise floor. Theoretical analysis proves reliable detection at extremely low SNR levels, a scenario common in battery-powered Io T sensors. We validate our approach via simulations over realistic Io T channel models and employ the Minimum Description Length (MDL) criterion to accurately estimate the active user count. Our results indicate that this blind multiuser detector can substantially improve network throughput and device scalability in dense Io T environments without prior synchronization or pilot overhead.

Keywords

References

  1. Zhang and H. Xu, “A Novel Recognition Method for Direct Sequence Spread Spectrum (DSSS) Signals Based on Secondary Power Spectrum,” Adv. Compute. Signals Syst., vol. 7, pp. 80–86, 2023.
  2. Chen, Yan, et al. "Time-reversal wireless paradigm for green internet of things: An overview." IEEE Internet of Things Journal 1.1 (2014): 81-98. org/10.1109/JIOT.2014.2308838
  3. Wei and Y. Xu, “DSSS Signal Detection Based on CNN,” Sensors, vol. 23, no. 15, p. 6691, 2023.
  4. Li and J. Chen, “Gaussian-Distributed Spread-Spectrum for Covert Communications,” Sensors, vol. 23, no. 8, p. 4081, 2023. doi.org/10.3390/s23156691
  5. Farid Samsami Khodadad, Shakiba Janalizadeh, An expert algorithm for spectrum sensing and signal detection in NOMA-enabled 5G networks, Expert Systems with Applications, Volume 214, 2023. org/10.1016/j.eswa.2022.119069
  6. Forouzesh, F. Samsami Khodadad, P. Azmi, A. Kuhestani and H. Ahmadi, "Simultaneous Secure and Covert Transmissions Against Two Attacks Under Practical Assumptions," in IEEE Internet of Things Journal, vol. 10, no. 12, pp. 10160-10171, 15 June15, 2023.doi.org/ 10.1109/JIOT.2023.3237640
  7. Nzea CN, Gautier R, Burel G. “Blind synchronization and sequences identification in CDMA transmissions”. MILCOM; November 2004. p. 1384–90.doi.org/ 1109/MILCOM.2004.1495144
  8. Nzea CN, Gautier R, Burel G. Parallel “blind multiuser synchronization and sequences estimation in multirate CDMA transmissions.” , IEEE-ACSSC; November 2006. p. 2157–61. doi.org/ 1109/ACSSC.2006.355150
  9. Nzea CN, Gautier R, Burel G. “Blind multiuser identification in multirate CDMA transmissions: a new approach” IEEE Conference on Signals, Systems and Computers; October–November 2006. p. 2162–66. doi.org/ 1109/ACSSC.2006.355151
  10. Burel, C. Bouder, "Blind estimation of the pseudo-random sequence of a direct sequence spread spectrum signal", Proc. of Military Communications Conference (MILCOM), October 2000.doi.org/ 10.1109/MILCOM.2000.904074
  11. Bouder, S. Azou, G. "Burel, "Performance analysis of a spreading sequence estimator for spread spectrum transmissions", J. Franklin nst. vol. 341, no .7 October 2004, pp. 595–614.doi.org/10.1016/j.jfranklin.2004.07.006
  12. N. Nsiala, R. Gautier, G. Burel "Parallel blind multiuser synchronization and sequence estimation in multirate CDMA transmision", Proc. 40th Asilomar Conference on Signals, Systems and Computers, Pacific Grove, 2006.doi.org/ 10.1109/ACSSC.2006.355150
  13. K. Tsatsanis, G.B. Giannakis, "Blind estimation of direct sequence spread spectrum signals in multipath”, IEEE Trans. Signal Process. vol. 45, no. 5, May 1997, pp. 1241–1252.doi.org/ 10.1109/78.575697
  14. K Chawla and D. V. Sarwate, “Parallel acquisition of PN sequences in DS-SS Systems”, IEEE Trans. Commun., vol. 42, pp.2155-2163, May 1994.doi.org/ 10.1109/26.285151
  15. K Chawla and D. V. Sarwate,”Acquisition of PN sequence in chip synchronous DS-SS systems using a random sequence model and the SPRT,”IEEE Trans. Commun., vol. 42, pp. 2325-2333, June 1994.doi.org/ 10.1109/26.293684
  16. Guolin, H. Min, Z. Ying, " PN code recognition and parameter estimation of PN-BPSK signal based on synchronous demodulation", Proc. 8th International Conference on Electronic Measurement and Instruments (ICEMI), 2007.doi.org/ 10.1109/ICEMI.2007.4350640
  17. Zhang, X.lin and Z. Zhou, “Blind estimation of the PN Sequences in lower SNR DS-SS signals, “IEICE trans, commun vol. E88-B, no7,pp. 3087-3089, July 2005.doi.org/ 10.1093/ietcom/e88-b.7.3087
Future Research on AI and IoT
Volume 1, Issue 2
August 2025
Pages 19-23

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History

  • Receive Date: 23 May 2025
  • Accept Date: 04 August 2025
  • First Publish Date: 04 August 2025
  • Publish Date: 01 August 2025

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