scholarly journals Generalized Receiver with Parallel Interference Cancellation for Multiuser Detection

2021 ◽  
Vol 16 ◽  
pp. 633-654
Author(s):  
Vyacheslav Tuzlukov
Keyword(s):  
Interference Cancellation ◽  
Code Division Multiple Access ◽  
Additive White Gaussian Noise ◽  
Direct Sequence ◽  
Parallel Interference Cancellation ◽  
Two Stage ◽  
Multiuser Detector ◽  
Complete Set ◽  
Optimal Values ◽  
Code Division Multiple

Parallel interference cancellation is considered as a simple yet effective multiuser detector for direct -sequence code-division multiple-access (DS-CDMA) systems. However, system performance be deteriorated due to unreliable interference cancellation in the early stages. Thus, a detector with the partial parallel interfere-nce cancellation in which the partial cancellation factors are introduced to control the interference cancellation level has been developed as a remedy. Although the partial cancellation factors are crucial, complete solutions for their optimal values are not available. In this paper, we consider a two-stage decoupled generalized receiver with the partial parallel interference cancellation. Using the minimum bit error rate (BER) criterion, we derive a complete set of optimal partial cancellation factors. This includes the optimal partial cancellation factors for pe-riodic and aperiodic spreading codes in channels with the additive white Gaussian noise and multipath chann-els. Simulation results demonstrate that the considered theoretical optimal partial cancellation factors agree clo-sely with empirical ones. The proposed two-stage generalized receiver with the partial parallel interference can-cellation using the derived optimal partial cancellation factors outperforms not only a two-stage, but also a three-stage conventional generalized receiver with the full parallel interference cancellation.

scholarly journals THE STUDY OF BIT ERROR RATE EVOLUTION IN A MOBILE COMMUNICATIONS SYSTEM USING DS – CDMA TECHNOLOGY

2017 ◽  
Vol 18 (2) ◽  
Author(s):  
ION POPA
Keyword(s):  
Mobile Communications ◽  
Bit Error Rate ◽  
Error Rate ◽  
Code Division Multiple Access ◽  
Additive White Gaussian Noise ◽  
Direct Sequence ◽  
Access Technology ◽  
M Sequence ◽  
Code Division Multiple ◽  
Communications System

<p>This paper follows the study of bit error rate evolution in a mobile communications system using DS – CDMA (Direct Sequence – Code Division Multiple Access) technology. We have assessed the bit error rate (BER) based on the signal/noise ratio, Eb/N0, and the number of users in the system. For this purpose, we have used M sequence and Orthogonal Gold sequence and the AWGN (Additive white Gaussian noise) transmission medium<strong>.</strong></p>

scholarly journals A proposed method for determination of weighted despreading sequences for a DS/CDMA system

2007 ◽  
Vol 3 (3) ◽  
Author(s):  
Younes Jabrane ◽  
Radouane Iqdour ◽  
Brahim Ait Es Said ◽  
Najib Naja
Keyword(s):  
Interference Cancellation ◽  
Fuzzy Systems ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Additive White Gaussian Noise ◽  
Multiple Access Interference ◽  
Code Division Multiple ◽  
Parameter Values ◽  
Gaussian Noise Channels

The steeping chip weighting waveforms are used in multiple access interference cancellation by emphasizing the received spreading signal, therefore, that allows to solve the problem of orthogonality for the chip waveforms. Our paper presents a useful method based on fuzzy systems to determine the despreading sequences weighted by the steeping chip weighting waveforms for Direct Sequence Code Division Multiple Access DS/CDMA. The validity of our proposed method has been tested by numerical examples for an Additive White Gaussian Noise channels and shows that the parameter values of the chip weighting waveforms are good and the Bit Error Rate performance of the system does not undergone any degradation.

Successive Interference Cancellation for DS-Optical PPM-CDMA Systems

2016 ◽  
Vol 37 (2) ◽  
Author(s):  
N. Alsowaidi ◽  
Tawfig Eltaif ◽  
M. R. Mokhtar
Keyword(s):  
Interference Cancellation ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Successive Interference Cancellation ◽  
Pulse Position Modulation ◽  
Direct Sequence ◽  
Signature Sequence ◽  
Cdma Systems ◽  
The One ◽  
Code Division Multiple

AbstractIn this paper we introduce a successive interference cancellation (SIC) scheme for direct sequence optical code division multiple access (DS-OCDMA) systems using pulse position modulation (PPM). Considering double-padded modified prime code (DPMPC) as a signature sequence code, results show that the system has better performance in terms of both capacity and bit error rate (BER) as compared to the one without cancellation scheme, where the system with SIC scheme can support up to 88 users while the system without SIC scheme can support only 38 users at similar BER=10

NOVEL LOW-COMPLEXITY ANT COLONY BASED MULTIUSER DETECTOR FOR DIRECT SEQUENCE CODE DIVISION MULTIPLE ACCESS

2005 ◽  
Vol 05 (02) ◽  
pp. 201-214 ◽  
Author(s):  
SAMER L. HIJAZI ◽  
BALASUBRAMANIAM NATARAJAN
Keyword(s):  
Code Division Multiple Access ◽  
Multiple Access ◽  
Low Complexity ◽  
Foraging Strategy ◽  
Ant Colony ◽  
Direct Sequence ◽  
Multiuser Detector ◽  
Sequence Code ◽  
Cooperative Foraging ◽  
Code Division Multiple

In this paper, we present a novel multiuser detection (MUD) technique based on ant colony optimisation (ACO), for synchronous direct sequence code division multiple access systems. ACO algorithms are based on the cooperative foraging strategy of real ants. While an optimal MUD design using an exhaustive search method is prohibitively complex, we show that the ACO-based MUD converges to the optimal bit-error-rate performance in relatively few iterations providing 95% savings in computational complexity. This reduction in complexity is retained even when considering users with unequal received powers.

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