How the Coherent Detector Works in Spread Spectrum Signals

Authors

Louay Habib Skef, Department of communication Techniques Engineering, Collage of Technical Engineering, Al-Farahidy UniversityFollow
Aymen Mohammed Khodayer, Department of communication Techniques Engineering, Collage of Technical EngineeringFollow
jenan J. abdulkareem, Department of communication Techniques Engineering, Collage of Technical EngineeringFollow

Keywords

Receiver operating characteristics (ROC), Energy detector, Cross-correlation detector, Ratio of odds (LR), False alarm probability (PFA), True detection probability (PD)

Document Type

Article

Abstract

This research investigates the detection of direct sequence spread spectrum (DSSS) signals, comparing the performance of a traditional energy detector with that of a cross-correlation detector. While energy detectors are widely used, they suffer from reduced sensitivity at low signal-to-noise ratios (SNR) and require accurate noise power estimation. In contrast, the cross-correlation detector utilizes the processing gain of DSSS signals to achieve higher detection accuracy without needing prior noise estimation. Using MATLAB simulations, Receiver Operating Characteristic (ROC) curves were generated for both detectors. Results show that the cross-correlation detector achieves up to 30% higher probability of detection (PD) at a false alarm probability (PFA) of 0.1 and SNR = –11 dB compared to the energy detector. This demonstrates the cross-correlation detector’s robustness and suitability for reliable DSSS signal detection in noisy environments.

Recommended Citation

Skef, Louay Habib; Khodayer, Aymen Mohammed; and abdulkareem, jenan J. (2025) "How the Coherent Detector Works in Spread Spectrum Signals," Al-Farahidi Expert Systems Journal: Vol. 1: Iss. 2, Article 3.
Available at: https://fesj.uoalfarahidi.edu.iq/journal/vol1/iss2/3