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

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.

کلیدواژه ها:

Asynchronous VPG DS-CDMA ، Secure Internet of things (Io T) Communication ، Autocorrelation- Based Detection ، Low Probability of Detection (LPD) ، Physical layer Security