Performance improvement in Multistage Multiuser DS-CDMA system over Rayleigh fading channel

AUTHOR(S):

TITLE

Performance improvement in Multistage Multiuser DS-CDMA system over Rayleigh fading channel

ABSTRACT

Direct Sequence Code Division Multiple Access (DS-CDMA) system is well known wireless technology. Multiple Access Interference (MAI) is a major problem in DS-CDMA system caused by its users. When the number of users increases the system performance gradually decreases especially in fading environment. In this paper, multistage multiuser detection techniques were introduced to detect the users data in presence of MAI. Multistage Multiuser Parallel Interference Cancellation (PIC) technique gives good performance but biased decision statistic problem is raised due to imperfect estimation of MAI as number of stages increases. To overcome biased decision statistic problem by Multistage Multiuser Partial Parallel Interference Cancellation (PPIC) technique is used to reduce the MAI partially stage by stage. But the problem is in PIC and PPIC computational complexity is very high when the number of stages increases. The computational complexity is minimized by using Multistage Difference PIC (DPIC) detection technique is based on the convergence nature of interference cancellation. Multistage Multiuser Partial Differencing Parallel Interference Cancellation (PDPIC) Technique is the combination of Difference PIC and Partial PIC. By using technique, Performance improved and computational complexity is minimized both are performed at a time. Simulation results shows that the partial difference PIC better performed (in terms of Bit Error Rate (BER)) than PIC and PPIC in fading environment.

KEYWORDS

Multiuser detection, MAI, PIC, PPIC, DPIC, PDPIC, Rayleigh channel

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Cite this paper

J.Ravindrababu, E.V.Krishna Rao. (2017) Performance improvement in Multistage Multiuser DS-CDMA system over Rayleigh fading channel. International Journal of Communications, 2, 68-76