An Innovative Modeling and Evaluating Bit Error Probability in Asynchronous DS-CDMA Systems with Rayleigh-Distributed Multiple Access Interference
[1] Department of Electrical Engineering, College of Engineering, Jouf University, Sakaka 72388, Saudi Arabia.
2 Department of Electrical Engineering, Faculty of Engineering, Al-Azhar University, Nasr City, Cairo 11884, Egypt.
Research Article
Open Access Research Journal of Engineering and Technology, 2025, 09(02), 056-065.
Article DOI: 10.53022/oarjet.2025.9.2.0096
Publication history:
Received 15 October 2025; revised on 26 November 2025; accepted on 29 November 2025
Abstract:
Recent developments in cellular mobile systems indicate substantial capacity issues for densely populated urban areas. Emerging wireless systems require increased data rates and flexibility to exceed capacity constraints. Traditional multiple access methods like Frequency Division Multiple Access (FDMA) and Time Division Multiple Access (TDMA) allow users to share fixed-spectrum resources with one another. Yet these techniques come to a halt when their channels or time slots are exhausted. Code Division Multiple Access (CDMA) was originally created for secure communication and anti-jamming purposes but has even higher capacity and better multipath interference resistance. Multiple Access Interference (MAI) is an important limitation on CDMA performance. Here we study the effect of MAI on the Bit Error Probability (BEP) of asynchronous Direct Sequence CDMA (DS-CDMA) systems. Standard Gaussian Approximation (SGA), Improved Gaussian Approximation (IGA), and simplified IGA as three examples in architecture, depend on the Central Limit Theorem which models MAI as a zero-mean Gaussian distribution. Theoretical Framework: The contribution of MAI for BEP estimation is made more meaningful based on modeling of MAI as a Rayleigh-distributed random variable (RDRV). Comparative analysis highlights the performance of our method using SGA, which we observe results with nonzero mean, which highlights the weaknesses of the existing approaches, as well as suggests new direction for better accuracy in predicting CDMA performance.
Keywords:
Code Division Multiple Access (CDMA); Bit Error Probability (BEP); Multiple Access Interference (MAI); Rayleigh Distribution; Asynchronous Systems
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