scholarly journals Statistical Analysis of Multiple Access Interference in Chaotic Spreading Sequence Based DS-CDMA Systems

2017 ◽  
Vol 21 (1) ◽  
pp. 34
Author(s):  
A. Litvinenko ◽  
E. Bekeris
Keyword(s):  
Statistical Analysis ◽  
Communication Systems ◽  
Multiple Access ◽  
Multiple Access Interference ◽  
Matlab Simulation ◽  
Spreading Sequence ◽  
Sequence Generation ◽  
Code Division Multiple ◽  
Correlation Properties ◽  
Spreading Sequences

This paper presents a statistical analysis of multiple access interference (MAI) in Direct Sequence Code Division Multiple Access (DS-CDMA) communication systems based on different types of chaotic spreading sequences. The probability distribution of the interference in a system with K users causing the MAI is studied using MATLAB simulation. For chaotic spreading sequence generation six different 1-D chaotic maps are used: modified Bernoulli, modified Tent, Gauss, Sine-Circle, Cubic and Pinchers map. A brief statistical analysis of the cross-correlation properties of the chaotic sequences generated by the aforementioned maps is also presented.

scholarly journals Suitable Spreading Sequences for Asynchronous MC-CDMA Systems

2018 ◽  
Vol 3 ◽  
pp. 9-13 ◽  
Author(s):  
Mouad Addad ◽  
Ali Djebbari
Keyword(s):  
Communication Systems ◽  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Multiple Access Interference ◽  
High Data ◽  
Research Areas ◽  
Rate Transmission ◽  
Cdma Systems ◽  
Code Division Multiple ◽  
Spreading Sequences

In order to meet the demand of high data rate transmission with good quality maintained, the multi-carrier code division multiple access (MC-CDMA) technology is considered for the next generation wireless communication systems. However, their high crest factor (CF) is one of the major drawbacks of multi-carrier transmission systems. Thus, CF reduction is one of the most important research areas in MC-CDMA systems. In addition, asynchronous MC-CDMA suffers from the effect of multiple access interference (MAI), caused by all users active in the system. Degradation of the system’s bit error rate (BER) caused by MAI must be taken into consideration as well. The aim of this paper is to provide a comparative study on the enhancement of performance of an MC-CDMA system. The spreading sequences used in CDMA play an important role in CF and interference reduction. Hence, spreading sequences should be selected to simultaneously ensure low CF and low BER values. Therefore, the effect that correlation properties of sequences exert on CF values is investigated in this study. Furthermore, a numerical BER evaluation, as a function of the signal-to-noise ratio (SNR) and the number of users, is provided. The results obtained indicate that a trade-off between the two criteria is necessary to ensure good performance. It was concluded that zero correlation zone (ZCZ) sequences are the most suitable spreading sequences as far as the satisfaction of the above criteria is concerned.

scholarly journals Computationally Efficient Chaotic Spreading Sequence Selection for Asynchronous DS-CDMA

2017 ◽  
Vol 13 (1) ◽  
pp. 75-80
Author(s):  
Anna Litviņenko ◽  
Artūrs Āboltiņš
Keyword(s):  
Multiple Access ◽  
Cross Correlation ◽  
Search Algorithm ◽  
Multiple Access Interference ◽  
Sequence Length ◽  
Spreading Sequence ◽  
Chaotic Sequences ◽  
Code Division Multiple ◽  
The Impact ◽  
Spreading Sequences

Abstract The choice of the spreading sequence for asynchronous direct-sequence code-division multiple-access (DS-CDMA) systems plays a crucial role for the mitigation of multiple-access interference. Considering the rich dynamics of chaotic sequences, their use for spreading allows overcoming the limitations of the classical spreading sequences. However, to ensure low cross-correlation between the sequences, careful selection must be performed. This paper presents a novel exhaustive search algorithm, which allows finding sets of chaotic spreading sequences of required length with a particularly low mutual cross-correlation. The efficiency of the search is verified by simulations, which show a significant advantage compared to non-selected chaotic sequences. Moreover, the impact of sequence length on the efficiency of the selection is studied.

scholarly journals Multigroup Synchronization in 1D-Bernoulli Chaotic Collaborative CDMA

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Sumith Babu Suresh Babu ◽  
R. Kumar
Keyword(s):  
Communication Systems ◽  
Multiple Access ◽  
Multiple Access Interference ◽  
Security Requirements ◽  
Wireless Communication Systems ◽  
Multiuser Transmission ◽  
User Capacity ◽  
Code Division Multiple ◽  
Pn Sequences ◽  
Correlation Properties

Code-division multiple access (CDMA) has played a remarkable role in the field of wireless communication systems, and its capacity and security requirements are still being addressed. Collaborative multiuser transmission and detection are a contemporary technique used in CDMA systems. The performance of these systems is governed by the proper accommodation of the users and by proper synchronization schemes. The major research concerns in the existing multiuser overloaded CDMA schemes are (i) statistically uncorrelated PN sequences that cause multiple-access interference (MAI) and (ii) the security of the user’s data. In this paper, a novel grouped CDMA scheme, the 1D-Bernoulli chaotic collaborative CDMA (BCC-CDMA), is introduced, in which mutually orthogonal chaotic sequences spread the users’ data within a group. The synchronization of multiple groups in this scheme has been analyzed under MAI limited environments and the results are presented. This increases the user capacity and also provides sufficient security as a result of the correlation properties possessed by the chaotic codes. Multigroup synchronization is achieved using a 1D chaotic pilot sequence generated by the Bernoulli Map. The mathematical model of the proposed system is described and compared with the theoretical model of the synchronization in CDMA, the simulation results of which are presented.

A Method of Constructing Quaternary Periodic Complementary Sequence Sets for Suppression of Multiple Access Interference in CDMA Communication Systems

2014 ◽  
Vol 543-547 ◽  
pp. 2323-2328
Author(s):  
Fan Xin Zeng ◽  
Zhen Yu Zhang ◽  
Lin Jie Qian
Keyword(s):  
Communication System ◽  
Communication Systems ◽  
Multiple Access ◽  
Binary Sequence ◽  
Multiple Access Interference ◽  
New Method ◽  
Complementary Sequence ◽  
The One ◽  
Spreading Sequences

For suppressing multiple access interference (MAI) in a CDMA communication system, complementary sequence sets are employed as spreading sequences in such system. In this paper, we present a method for constructing a family of quaternary periodic complementary sequence sets, which arises from the conversion of the existing binary periodic complementary sequence sets with odd period of sub-sequences. The period of sub-sequences in the proposed sequence sets is twice as long as the one of the binary sequence sets employed, which is a drawback in the proposed method. Finally, some examples are given in order to illuminate the validity of the new method.

Blind Multiuser Receivers for Chaos Based Communications

2003 ◽  
Vol 13 (08) ◽  
pp. 2353-2359 ◽  
Author(s):  
Francisco Argüello ◽  
Manuel Bugallo ◽  
Juan López
Keyword(s):  
Communication Systems ◽  
Multiple Access ◽  
Good Deal ◽  
Multiple Access Interference ◽  
Detection Techniques ◽  
Multiuser Receivers ◽  
Cdma Systems ◽  
Blind Receivers ◽  
Code Division Multiple ◽  
The Impact

Recently, there has been a good deal of interest in the use of chaotic signals for direct sequence code division multiple access (DS-CDMA) communication systems. The capacity of DS-CDMA systems is interference-limited, and can therefore be increased by techniques that suppress interference. This letter is devoted to the evaluation of the impact of blind multiuser detection techniques on chaos based DS-CDMA systems. Blind receivers can suppress multiple access interference and do not require knowledge of the code sequences and propagation channels of the interference. We demonstrate that, for chaotic sequence-based communications, blind multiuser receivers significantly improve the BER with respect to single-user receivers, and that their use is practically essential with a high number of users.

scholarly journals A New Code Family for QS-CDMA Visible Light Communication Systems

2018 ◽  
Vol 3 ◽  
pp. 5-8 ◽  
Author(s):  
Mouad Addad ◽  
Ali Djebbari
Keyword(s):  
Visible Light ◽  
Communication Networks ◽  
Communication Systems ◽  
Multiple Access ◽  
Multipath Propagation ◽  
Multiple Access Interference ◽  
Visible Light Communication ◽  
Wireless Communication Networks ◽  
Strong Candidate ◽  
Code Division Multiple

Visible light communication (VLC) is a promising technology for wireless communication networks. Optical code division multiple access (OCDMA) is a strong candidate for VLC-based applications. The predominant source of bit error in OCDMA is the multiple access interference (MAI). To eliminate MAI in synchronous OCDMA, zero cross correlation (ZCC) codes have been proposed. However, synchronization problems and multipath propagation introduce relative non-zero time delays. Therefore, the zero correlation zone (ZCZ) concept was introduced. In this paper, we propose a new method for generating ZCC codes. The proposed construction can accommodate any number of users with flexible Hamming weight. The numerical results obtained show that the proposed codes significantly reduce MAI, compared to ZCC, as well as ZCZ codes.

DRIVING SYNCHRONIZATION OF SPATIOTEMPORAL CHAOS AND ITS APPLICATIONS IN CDMA COMMUNICATIONS

2001 ◽  
Vol 11 (12) ◽  
pp. 3117-3124
Author(s):  
REN YONG ◽  
YONGXIANG XIA ◽  
XIUMING SHAN ◽  
YUAN JIAN
Keyword(s):  
Communication Systems ◽  
Original System ◽  
Spatiotemporal Chaos ◽  
Sequence Generation ◽  
Chaotic Sequences ◽  
Spatial Periodicity ◽  
Pseudo Noise ◽  
Code Division Multiple ◽  
User Interference ◽  
Spreading Sequences

This paper investigates the driving synchronization of spatiotemporal chaos. Using this method, synchronization could be achieved efficiently. By improving the driving sequence generation method, the spatial periodicity in the original system is overcome. Large quantities of chaotic sequences are available, which possess the excellent properties expected in Code Division Multiple Access (CDMA) communications. These chaotic sequences can be used as the spreading sequences in place of the traditional pseudo-noise sequences. We also evaluate the performance of the chaotic CDMA communication systems and compute the average bit error rate caused by the multi-user interference and the noise in the channel. The theoretical and simulation results show the excellent performance of the scheme.

scholarly journals A Markov Based Detection for Broadband over Power Line Communications (PLC)

1970 ◽  
Vol 44 (4) ◽  
pp. 441-444
Author(s):  
M Morshed ◽  
P Sarker ◽  
RC Roy
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Access ◽  
Multiple Access Interference ◽  
Wireless Communication Systems ◽  
Power Line Communications ◽  
Impulsive Noises ◽  
Finite State ◽  
Promising Solution ◽  
Code Division Multiple

Successful development of Broadband over Power Lines (BPL) is obviously a potential solution for wireless communication systems with the existing infrastructure. Multi-Carrier Code Division Multiple Access (MC-CDMA) with Orthogonal Frequency Division Multiplexing (OFDM) modulation technique is a promising solution for a frequency selective fading with impulsive noises of the PLC channel. A linear iterative receiver with a Finite State Markov Channel (FSMC) model is proposed to remove Multiple Access Interference (MAI) and Inter Symbol Interferences (ISI). In this paper we focused on Maximum Likelihood (ML) feedback detection by introducing FSMC to get significant improvement in Bit Error Rate (BER). This model of the receiver is more robust against Gaussian colored and impulsive noises of the PLC channel. Keywords: FSMC; MC-CDMA; OFDM; MAI; ISI DOI: 10.3329/bjsir.v44i4.4595 Bangladesh J. Sci. Ind. Res. 44(4), 441-444, 2009

scholarly journals WON-OCDMA System Based on MW-ZCC Codes for Applications in Optical Wireless Sensor Networks

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 539
Author(s):  
Saleh Seyedzadeh ◽  
Andrew Agapiou ◽  
Majid Moghaddasi ◽  
Milan Dado ◽  
Ivan Glesk
Keyword(s):  
Optical Networks ◽  
Video Surveillance ◽  
Multiple Access ◽  
Optical Sensing ◽  
Multiple Access Interference ◽  
Service Differentiation ◽  
Sensor Data ◽  
Variable Weight ◽  
Code Division Multiple ◽  
The Impact

The growing demand for extensive and reliable structural health monitoring resulted in the development of advanced optical sensing systems (OSS) that in conjunction with wireless optical networks (WON) are capable of extending the reach of optical sensing to places where fibre provision is not feasible. To support this effort, the paper proposes a new type of a variable weight code called multiweight zero cross-correlation (MW-ZCC) code for its application in wireless optical networks based optical code division multiple access (WON-OCDMA). The code provides improved quality of service (QoS) and better support for simultaneous transmission of video surveillance, comms and sensor data by reducing the impact of multiple access interference (MAI). The MW-ZCC code’s power of two code-weight properties provide enhanced support for the needed service differentiation provisioning. The performance of this novel code has been studied by simulations. This investigation revealed that for a minimum allowable bit error rate of 10−3, 10−9 and 10−12 when supporting triple-play services (sensing, datacomms and video surveillance, respectively), the proposed WON-OCDMA using MW-ZCC codes could support up to 32 simultaneous services over transmission distances up to 32 km in the presence of moderate atmospheric turbulence.

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