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Journal articles on the topic 'Direct-Sequence Code Division Multiple Access (DS-CDMA)'

Author: Grafiati

Published: 4 June 2021

Last updated: 7 September 2023

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1

Mandalapu, Harinath, and B. Murali Krishna. "FPGA implementation of DS-CDMA Transmitter and Receiver." International Journal of Reconfigurable and Embedded Systems (IJRES) 6, no. 3 (2018): 179. http://dx.doi.org/10.11591/ijres.v6.i3.pp179-185.

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Direct sequence spread Spectrum (DSSS) is also known as direct sequence code division multiplexing. In direct sequence spread spectrum the stream of information to be transmitted is divided into small pieces each of which is allocated across to a frequency channel across the spectrum. Data signal at the point of transmission is collaborated with a higher data-rate bit sequence (also called chipping code) that divides the data according to a spreading ratio. A redundant chipping code helps the signal resist interference and also enables the original data to be recovered if data bits are damaged

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2

Argüello, Francisco, Manuel Bugallo, and Juan López. "Blind Multiuser Receivers for Chaos Based Communications." International Journal of Bifurcation and Chaos 13, no. 08 (2003): 2353–59. http://dx.doi.org/10.1142/s0218127403008028.

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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 c

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3

Alami Hassani, Aicha, Mohcine Zouak, and Mostafa Mrabti. "Contribution to Synchronization and Tracking Modelisation in a CDMA Receiver." Journal of Engineering 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/936495.

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We propose and analyze a noncoherent receiver with PN code tracking for direct sequence code division multiple access (DS-CDMA) communication systems. We employ the delay-lock loop (DLL) architectures for the tracking stage. The choice of DLL parameters is studied with special focus on DS-CDMA communication systems and orthogonality conditions. We described the modeling and simulation of the NCO using hardware description language VHDL. Details of the VHDL implementation are shown.

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4

Uddin, Jia, Mohammed Faisal, Md Facihul Azam, and A. F. M. Muzahidur Rahman. "Performance Analysis of Multicarrier Code Division Multiple Access over Rayleigh Fading Channel." Advanced Materials Research 457-458 (January 2012): 985–88. http://dx.doi.org/10.4028/www.scientific.net/amr.457-458.985.

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Recently, multi-carrier transmission schemes have been introduced into Code Division Multiple Access (CDMA) systems to gain advantages for high data rate transmission as well as security. Due to pseudorandom code there is no chance to Inter Symbol Interference (ISI). There are different techniques to mitigate multipath fading. One of the method is to transmit identical narrowband direct-sequence (DS) waveforms in parallel over a number of sub-channels using frequency diversity. Implementation this multi-carrier modulation technique in CDMA system is known as multi-carrier CDMA (MC-CDMA). In Ra

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Men, Wei, Liang Zhang, Jing-wei Yin, Xiao Han, and Hong-yu Yin. "Blind beamforming-based strong interference suppression in underwater acoustic direct-sequence code-division multiple-access systems." Journal of the Acoustical Society of America 152, no. 4 (2022): 2128–39. http://dx.doi.org/10.1121/10.0014598.

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In an underwater acoustic direct-sequence code-division multiple-access (DS-CDMA) system, the performance of the conventional receiver is severely limited by the strong multiple-access interferences, which is due to the near-far effect. In this paper, a time-frequency-time with eigendecomposition-based blind beamformer (TFT-EBB) method is proposed for a distant user to suppress strong interference from a nearby user in DS-CDMA underwater acoustic communications. When the interference level is moderately higher than that of the desired signal, the TFT-EBB method can estimate the composite steer

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6

Bilal Abdalla, Khalid Hamid. "Simulation Performance of CDMA/QA in Mobile Channel." FES Journal of Engineering Sciences 5, no. 1 (2011): 14. http://dx.doi.org/10.52981/fjes.v5i1.32.

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The aim of this work is to study, analyze and evaluate software the link performance of mobile communication system under the impairment of the multiple access schemes, down-link thermal noise and the multipath fading in the mobile channel. For this purpose, modeling and simulation has been used to study the effects of nonlinearities in mobile channel using spread spectrum for Direct Sequence Code Division Multiple Access, with Quadrature Amplitude Modulation (DS-CDMA/QAM).

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Liu, Xiao Zhi, Da Wei Feng, and Tian Shuang Zhang. "Multi-User Detection of DS-CDMA Based on Improved-FastICA." Applied Mechanics and Materials 128-129 (October 2011): 633–36. http://dx.doi.org/10.4028/www.scientific.net/amm.128-129.633.

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Multi-user detection (MUD) is used to control multiple access interference (MAI) and promote system performance and capacity, which is one of the key technology for CDMA system. Independent component analysis (ICA) aims to recover a set of unknown mutually independent source signals from theirs observed mixtures without knowledge of the mixing coefficients. FastICA, one of the ICA methods, has been successfully applied in various fields. But the classical FastICA does not converge quickly. In multi-user detection of direct sequence code division multiple access (DS-CDMA) system, we proposes an

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Hassani, A., Y. Garrouani, F. Mrabti, and F. Abdi. "Acquisition Time and Probabilities of Detection and False Alarm in Direct Sequence Code Division Multiple Access Systems." Jordan Journal of Electrical Engineering 9, no. 1 (2023): 60. http://dx.doi.org/10.5455/jjee.204-1668454435.

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Multiple access interference (MAI) is one of the most important issues to consider in the design, implementation and operation of 5G systems using code division multiple access (CDMA) technique based on spread spectrum that offers a more flexible solution, compared to other techniques. Especially, it permits a much higher user bit rate, due to the bandwidth allocated to the emitted signal; thus, allowing very attractive multimedia services. In this paper, we develop the expressions of the detection probability, false alarm probability and the average acquisition time - in a direct sequence CDM

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Litvinenko, A., and E. Bekeris. "Statistical Analysis of Multiple Access Interference in Chaotic Spreading Sequence Based DS-CDMA Systems." Electronics ETF 21, no. 1 (2017): 34. http://dx.doi.org/10.7251/els1721034l.

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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 gen

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Varzakas, Panagiotis. "Capacity Estimation for a DS-CDMA System in Nakagami-m Fading." WSEAS TRANSACTIONS ON COMMUNICATIONS 21 (March 3, 2022): 31–33. http://dx.doi.org/10.37394/23204.2022.21.6.

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Ιn this paper, a novel closed-form expression of the Shannon average channel capacity per user for direct- sequence code-division multiple access (DS-CDMA) systems, operating in Nakagami-m fading, with optimum RAKE reception, is obtained. Numerical results are also presented to illustrate the proposed mathematical analysis and to point out the effect of the fading severity on the user’s average channel capacity.

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Litviņenko, Anna, and Artūrs Āboltiņš. "Computationally Efficient Chaotic Spreading Sequence Selection for Asynchronous DS-CDMA." Electrical, Control and Communication Engineering 13, no. 1 (2017): 75–80. http://dx.doi.org/10.1515/ecce-2017-0011.

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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 particularl

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LIM, ALVIN, and KUI MOK. "PERFORMANCE EVALUATION OF ADAPTIVE MEDIA ACCESS CONTROL PROTOCOLS FOR PERVASIVE WIRELESS NETWORKS." Journal of Interconnection Networks 03, no. 03n04 (2002): 253–72. http://dx.doi.org/10.1142/s0219265902000665.

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As pervasive and high-density wireless networks become increasingly common, it is critical to address the problems of intermittent disconnection, high error rate and collision that cause degradation in the performance of wireless media access control protocols, such as slotted ALOHA Time Division Multiple Access (slotted ALOHA/TDMA) and Direct Sequence Code Division Multiple Access (DS/CDMA). We propose adaptive techniques for improving performance of media access protocols through awareness of the mobile communication environment. These techniques involve detection of intermittent disconnecti

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Biteur, Kada, Belkacem Benadda, and Ahmed Ayad. "New approach to a DS-CDMA-UWB system using a pseudo orthogonal code (POC)." Facta universitatis - series: Electronics and Energetics 35, no. 4 (2022): 483–93. http://dx.doi.org/10.2298/fuee2204483b.

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Ultra-Wideband Direct Sequences Code Division Multiple Access (DS-DMA) plays an important role in the case of multi-terminal multi-application communications of UWB devices. In the case of UWB systems that exploit the injection of the pulse itself directly to the antenna hence the very wide bandwidth, generation of suitable DS-CDMA codes poses a real challenge. In this paper we will describe our novel UWB transmission which uses pseudo-orthogonal time code (POC) as DS-CDMA sequences. The suggested codes are unipolar sequences with chips that may be dynamically modified to target a certain numb

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Mvuma, Aloys. "Adaptive IIR Filters for Single Interference Suppression in a BPSK DS CDMA System In Rayleigh Fading Channel." Tanzania Journal of Engineering and Technology 30, no. 1 (2007): 65–73. http://dx.doi.org/10.52339/tjet.v30i1.398.

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In this paper, effect of a single narrow-band interference (NBI) on bit error rate (BER) performance for a binary phase shift keying (BPSK) synchronous direct-sequence code-division multiple access (DS CDMA) communication system operating in a frequency nonselective Rayleigh fading channel is analyzed. Second-order adaptive infinite impulseresponse (IIR) notch filters with plain gradient algorithm (GA) for suppression of NBI in the DS CDMA system are proposed. A general closed-form BER expression for the DS CDMA system with NBI suppression second order adaptive IIR notch filters is derived bas

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15

Zope, Rajendrakumar Govinda, and Balasaheb Shrirangrao Agarkar. "Channel Estimation for DS-CDMA Rake Receiver using Sparse Recovery Approach." International Journal of Recent Technology and Engineering (IJRTE) 11, no. 1 (2022): 41–46. http://dx.doi.org/10.35940/ijrte.f6841.0511122.

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In the literature of direct-sequence code-division multiple-access (DS-CDMA), for issues related to channel estimation, some exclusive architectures have been proposed, which are characterized by known channel noise statistics and noise observation. But in reality, the channel parameters are frequently assessed utilizing training sequences that lead to difficulty in obtaining the channel noise statistics. Channel estimation quality has been proved to play an important role in the performance of rake receiver. This paper addresses the issues of optimizing DS–CDMA rake receiver channel estimatio

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Srinivasa, Rao V., Kumar P. Vinay, S. Balaji, Khan Habibulla, and Kumar T. Anil. "Robust Multiuser Detection in Synchronous DS-CDMA System with MRC Receive Diversity over Nakagami-m Fading Channel." Advanced Engineering Forum 4 (June 2012): 43–50. http://dx.doi.org/10.4028/www.scientific.net/aef.4.43.

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This paper presents the robust multiuser detection in synchronous direct sequence-code division multiple access (DS-CDMA) systems with Maximal Ratio Combiner (MRC) receive diversity over frequency-nonselective, slowly fading Nakagami-m channels in a non-Gaussian environment. Average probability of error is derived for decorrelating detector over single path Nakagami-m fading channel. A new M-estimator proposed to robustify the detector is studied and analyzed. Simulation results show that the new M-estimator outperforms linear decorrelating detector, the Huber, and the Hampel estimator based d

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N. Motade, Sumitra, and Anju V. Kulkarni. "Incremental gradient algorithm for multiuser detection in multi-carrier DS-CDMA system under modulation schemes." International Journal of Engineering & Technology 7, no. 2.6 (2018): 311. http://dx.doi.org/10.14419/ijet.v7i2.6.11270.

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Nowadays, Multicarrier Direct sequence code division multiple access (MC DS-CDMA) systems are used in mobile communication. Performance of these systems are limited by multiple access interference (MAI) created by spread-spectrum users in the channel as well as background channel noise. This paper proposes an incremental gradient descent (IGD) multi-user detection (MUD) for MC DS-CDMA system that can achieve near-optimum performance while the number of users is linear in its implementation complexity. The IGD algorithm make an effort to perform optimum MUD by updating one user's bit decision e

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Cheng, Hao, Na Yu, and Jun Liu. "Improved Natural Gradient Algorithms for Multi-Channel Signal Separation." Applied Mechanics and Materials 651-653 (September 2014): 2326–30. http://dx.doi.org/10.4028/www.scientific.net/amm.651-653.2326.

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In this paper, an Multi-channel blind separation of Direct Sequence Code Division Multiple Access (DS-CDMA) has been introduced. Most of which we assume statistically stationary sources as well as instantaneous mixtures of signals using blind source separation (BSS) algorithms. In practicality, the CDMA sources received are convolute mixing. A more complex blind separation algorithm is required to achieve better source separation. Based on the minimizing the average squared cross-output-channel-correlation, the proposed scheme obtains the better source separation. Simulation results show that

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Elmissaoui, Taoufik. "Multi-Access Techniques Comparison for Remote Lab System." International Journal of Online and Biomedical Engineering (iJOE) 19, no. 12 (2023): 4–15. http://dx.doi.org/10.3991/ijoe.v19i12.39681.

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Remote lab systems are one of the essential requirements for an increased academic productivity in the modern digital world. These systems support and facilitate effective migration from face-to-face classroom education to online education. Digital technology applications and processes are required to easily build a remote lab system. With the availability of multiple access techniques, users can comfortably share laboratory equipment among themselves. The sharing of resources using the remote lab system is highly required for a smooth deployment and implementation of online education. This pa

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20

Wang, Wei, and Chunyan Han. "H∞Channel Estimation for DS-CDMA Systems: A Partial Difference Equation Approach." Mathematical Problems in Engineering 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/307342.

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In the communications literature, a number of different algorithms have been proposed for channel estimation problems with the statistics of the channel noise and observation noise exactly known. In practical systems, however, the channel parameters are often estimated using training sequences which lead to the statistics of the channel noise difficult to obtain. Moreover, the received signals are corrupted not only by the ambient noises but also by multiple-access interferences, so the statistics of observation noises is also difficult to obtain. In this paper, we will investigate theH∞channe

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Tuzlukov, Vyacheslav. "Performance of Generalized Receiver Employed by Broadband Multicarrier DS-CDMA System Using Space-Time Spreading-Assisted Transmit Diversity." WSEAS TRANSACTIONS ON COMMUNICATIONS 20 (September 29, 2021): 152–71. http://dx.doi.org/10.37394/23204.2021.20.21.

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In this paper the multicarrier direct-sequence code-division multiple access (MC DS-CDMA) using space-time spreading assisted transmit diversity is investigated in the context of broadband wireless communi-cations systems constructed based on the generalized approach to signal processing in noise over frequency-se-lective Rayleigh fading channels. We consider the issue of parameter design for the sake of achieving high-ef-ficiency communications in various dispersive environments. In contrast to the conventional MC DS-CDMA wireless communication system employing the time (T)-domain spreading o

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Dahmane, Adel Omar, and Lotfi Mejri. "FPGA Implementation of Block Parallel DF-MPIC Detectors for DS-CDMA Systems in Frequency-Nonselective Channels." Research Letters in Communications 2008 (2008): 1–5. http://dx.doi.org/10.1155/2008/435756.

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Multistage parallel interference cancellation- (MPIC-) based detectors allow to mitigate multiple-access interference in direct-sequence code-division multiple-access (DS-CDMA) systems. They are considered serious candidates for practical implementation showing a good tradeoff between performance and complexity. Better performance is obtained when decision feedback (DF) is employed. Although MPIC and DF-MPIC have the same arithmetic complexity, DF-MPIC needs much more FPGA resources when compared to MPIC without decision feedback. In this letter, FPGA implementation of block parallel DF-MPIC (

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Sirithummachak, P., and C. Benjangkaprasert. "Adaptive Equalizer for DS-CDMA Multi-User Communication System Using Sign-Algorithm Based on Laguerre Filter Structure." Applied Mechanics and Materials 548-549 (April 2014): 1231–34. http://dx.doi.org/10.4028/www.scientific.net/amm.548-549.1231.

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This paper proposes a sign-algorithm based on adaptive Laguerre filter structure for improving the performance of the direct sequence-code division multiple access (DS-CDMA) communication system. The proposed adaptive equalizer employs a combination of sign and least mean square (LMS) algorithms to minimizing the effect of inter-symbol interference (ISI) that arises due to multipath propagation, and the computational complexity of equalizer. The performance of proposed equalizer was compared with traditional equalizers such as LMS and RLS algorithms in terms of varying path. The function detai

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Tuzlukov, Vyacheslav. "Generalized Receiver with Decision-Feedback Equalizer for Multicode Wideband DS-CDMA." WSEAS TRANSACTIONS ON CIRCUITS AND SYSTEMS 21 (September 1, 2022): 202–22. http://dx.doi.org/10.37394/23201.2022.21.23.

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In the present paper, a chip-level minimum mean-square-error (MMSE) decision-feedback equalizer for the downlink receiver of multicode wideband direct sequence code-division multiple access (DS-CDMA) wireless communication systems over frequency-selective channels is investigated. Firstly, the MMSE per sym-bol achievable by an optimal decision-feedback equalizer is derived, assuming that all interchip interference (ICI) of the desired user can be eliminated. The MMSE of the decision-feedback equalizer is always less than or at most equal to that of linear equalizers. When all the active codes

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Wang, Feng, and Xuan De Ji. "A Joint Chip Equalization Adaptive Rake Receiver for DS-CDMA UWB Systems over ISI Channels." Advanced Materials Research 505 (April 2012): 274–81. http://dx.doi.org/10.4028/www.scientific.net/amr.505.274.

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There is serious inter-symbol interference (ISI) when ultra-wideband (UWB) wireless communication systems work at high data speed since there is much larger channel delay spread. The serious ISI becomes a major factor that affects the performance of UWB systems. In this paper, suppression ISI is developed for direct sequence spread-code division multiple access (DS-CDMA) UWB systems with a high data speed, and a joint chip equalization adaptive Rake (JCE-Rake) receiver is proposed. The proposed JCE-Rake receiver spreads the number of traditional Rake receiver taps to collect multi-path compone

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Khan, Mr Wasim, Mrs Nilofar Khan, and Sanmati Jain. "BER performance analysis of Subtractive interference cancellation (SIC) Using Rayleigh channel in DS-CDMA Receiver system." INTERNATIONAL JOURNAL OF COMPUTERS & TECHNOLOGY 13, no. 6 (2014): 4603–14. http://dx.doi.org/10.24297/ijct.v13i6.2523.

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In this paper, we present and analyze the performance of a parallel interference cancellation (PIC) scheme for multicarrier (MC) direct-sequence code-division multiple-access (DS-CDMA) systems. In order to mitigate the multi-path interference (MPI) in the DS CDMA system. At each cancellation stage in the proposed PIC scheme, on each subcarrier, a weighted sum of the soft outputs of the other users in the current stage is cancelled from the soft output of the desired user to form the input to the next stage. At the last stage, the interference cancelled outputs from all the subcarriers are maxi

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Umamaheswari, R., M. Ramya Princess, and P. Nirmal Kumar. "Improved Whale Optimized MLP Neural Network-Based Learning Mechanism for Multiuser Detection in MIMO Communication System." Journal of Circuits, Systems and Computers 29, no. 15 (2020): 2050239. http://dx.doi.org/10.1142/s0218126620502394.

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Direct-Sequence Code Division Multiple Access (DS-CDMA) is a digital method to spread spectrum modulation for digital signal transmission. We propose to detect signal in DS-CDMA communication using the learning mechanism. Initially, the user signals are spread using the respective pseudo-noise (PN) code where the input signal is multiplied with the code which is then modulated using the quadrature phase shift keying (QPSK) modulator. The modulated signal is then transmitted in a 3G/4G channel considering all types of fading. The transmitted signal is received by the antenna array which is perf

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She, Feng, Hsiao Hwa Chen, and Hongyang Li. "Joint Angular and Time Diversity of Multi-Antenna CDMA Systems in Wireless Fading Channels." International Journal of Wireless Networks and Broadband Technologies 1, no. 1 (2011): 1–14. http://dx.doi.org/10.4018/ijwnbt.2011010101.

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In this paper, a multi-antenna based receiver structure for direct sequence code division multiple access (DS/CDMA) system is proposed. The proposed scheme exploits the excellent time resolution of a CDMA RAKE receiver and uses an antenna array beamforming structure to resolve multipath returns in both angular and time domains. A much higher diversity gain than that based only on the time domain diversity can be achieved. This work suggests a new space-time diversity paradigm, namely angular-time diversity, which differs from traditional Alamouti-type space-time coded schemes. The impairments

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Varzakas, P. "Statistics of the Channel Capacity in a Cellular DS/FFH-CDMA Rayleigh Fading System." WSEAS TRANSACTIONS ON INFORMATION SCIENCE AND APPLICATIONS 18 (December 31, 2021): 151–55. http://dx.doi.org/10.37394/23209.2021.18.18.

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In this paper, we derive analytically the probability density function (pdf) of the theoretically achievable average channel capacity per user (in the Shannon sense) for a constant total system’s allocated bandwidth hybrid direct-sequence/fast frequency hopping code-division multiple-access (DS/FFHCDMA) cellular system, when operating in a Rayleigh fading environment. Then, the analysis leads to a theoretical novelclosed form expression for the pdf of the channel capacity, which relates the pdf of the channel capacity per user and all system’s parameters. In addition, the probability that the

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Rani, Ankita, and Deepak Kedia. "Performance Analysis of 2-D Prime Codes Encoded Optical CDMA System." Journal of Optical Communications 40, no. 4 (2019): 463–72. http://dx.doi.org/10.1515/joc-2017-0115.

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Abstract Optical code division multiple access (OCDMA) system provides highly secured transmission in addition to its capabilities to support asynchronous transmission and soft blocking. Two-dimensional OCDMA codes are chosen in this paper due to their high cardinality, good spectral efficiency and flexibility in their construction methods against direct sequence codes. This paper focuses on study of impact of multiple access interference (MAI) at high data rates for 2-D prime codesbased OCDMA system. It is shown that how the change in number of simultaneous users affects the transmission qual

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Cotae, Paul, and Matt Aguirre. "Method for Minimizing Total Generalized Squared Correlation of Synchronous DS-CDMA Signature Sequence Sets in Multipath Channels." Journal of Communications Software and Systems 2, no. 1 (2017): 20. http://dx.doi.org/10.24138/jcomss.v2i1.302.

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We characterize the Total Generalized Squared Correlation (TGSC) for a given signature sequence set used in uplink synchronous code division multiple access (S-CDMA) when channel state information is known perfectly at bothtransmitter and receiver. We give a definition of the TGSC based on the eigenvalues of Gram matrix associated to signature sequences set for multipath channels in the presence of the colored noise. Total Squared Correlation (TSC) and Total Weighted Squared Correlation (TWSC) measures are particular cases of TGSC. We present a method for minimizing TGSC (TSC, TWSC) in multipa

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Herdiana, Budi, Muhammad Aria, and Jana Utama. "PEMBANGKITAN DATA ACAK TERSEBAR DIRECT SEQUENCE SPREAD SPECTRUM PADA LAJU DATA BERKECEPATAN RENDAH UNTUK APLIKASI TEKNOLOGI CODE DIVISION MULTIPLE ACCESS." SINERGI 21, no. 3 (2017): 187. http://dx.doi.org/10.22441/sinergi.2017.3.005.

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Salah satu kelebihan utama sistem komunikasi Spread Spectrum adalah kemampuannya mengirimkan data informasi disertai kode-kode unik sehingga hanya perangkat penerima tertentu saya yang mampu mendeteksinya. Sangat banyak metode pembangkitan kode unik pada spread spectrum ini yang mana salah satunya adalah direct sequence. Penerapan metode ini banyak direalisasikan pada teknologi CDMA dikarenakan kesederhanaan rancangan dan relatif mudah dalam menganalisis karakteristik kerja sistemnya terutama bagian sebaran kode unik pada sebuah lebar pita transmisi radio. Sumber kode unik dalam penelitian ini

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Zhu, Yun Hang, Qiong Cai, and Xiu Liang Huang. "Research on Key Technologies in Multi-Robotic Spread Spectrum Communication System." Advanced Materials Research 756-759 (September 2013): 2401–5. http://dx.doi.org/10.4028/www.scientific.net/amr.756-759.2401.

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It has become a hot research topic that to improve the coordination performance of multi-robotic system by communication. With rapid development of wireless communication and robot technologies, multi-robotic system based on spread-spectrum technology has become product of combining two technologies. Code Division Multiple Access (CDMA) technology is applied in multi-robotic communication system here. According to the modified m-Walsh sequence got by the way of analyzing the relation characteristic of Walsh-code and m-sequence, the best direct sequence spread spectrum (DSSS) PN code and the im

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Gultom, Imeldawaty. "CDMA Modulation for Communication System Environment using Frequency Hopping Spread Spectrum." International Innovative Research Journal of Engineering and Technology 6, no. 1 (2020): EC—1—EC—13. http://dx.doi.org/10.32595/iirjet.org/v6i1.2020.131.

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In this paper, an overall framework for a joint Special emphasis is placed on the communication segment of the sensing system at 85 GHz. Code division multiplexing using frequency hopping spread spectrum signals is implemented at 85 ghz to take advantage of reduced interference between ambient communication. The framework, which spans the entire chain of signal processing, mat lab is enabled, explained, and simulated using data networking. A template, able to scatter, fraud detection, including radio frequency-block and synchronization non-idealities are built up and analyzed. Also, the implem

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Saragih, Hoga, and Fendy Santoso. "Capture Delay Analysis on the Throughputs of Direct-Sequence Code Division Multiple Access (DS-CDMA) with Slotted-ALOHA (S-ALOHA) Systems over Nakagami/Nakagami Fading Channels." International Journal of Wireless Information Networks 18, no. 3 (2011): 186–92. http://dx.doi.org/10.1007/s10776-011-0144-2.

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Tuzlukov, Vyacheslav. "Generalized Receiver with Parallel Interference Cancellation for Multiuser Detection." WSEAS TRANSACTIONS ON SYSTEMS AND CONTROL 16 (December 9, 2021): 633–54. http://dx.doi.org/10.37394/23203.2021.16.59.

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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

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Kadhim, Nader Abdullah, Ali jawad Alrubaie, and Ameer Al-khaykan. "Two cross coupled and Madgwicks filter for estimation of multi-channel dividing systems." Indonesian Journal of Electrical Engineering and Computer Science 27, no. 1 (2022): 262. http://dx.doi.org/10.11591/ijeecs.v27.i1.pp262-270.

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The estimates of Rayleigh fading channels are rapidly changing in multi carrier direct sequence code division multiple access (MC-DS-CDMA) multiplexing systems. The most widely accepted answer to this issue is the conventional solution least square (LS) or mean square error estimator (MMSE) using the recursive least squares algorithm (RLS) or the least mean squares (LMS) algorithm. In much of the previous work, only one Kalman filter was used for estimation. In this paper, a Kalman filter is used with a Madgwicks filter together to satisfy the fading problems. However, this requires a priori e

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Kochanska, Iwona, Roman Salamon, Jan H. Schmidt, and Aleksander M. Schmidt. "Study of the Performance of DSSS UAC System Depending on the System Bandwidth and the Spreading Sequence." Sensors 21, no. 7 (2021): 2484. http://dx.doi.org/10.3390/s21072484.

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A signal transmitted in an Underwater Acoustic Communication (UAC) system operating in a shallow-water channel suffers from strong time dispersion due to multipath propagation. This causes the Inter-Symbol Interference (ISI) observed in the received signal, which significantly limits the communication system’s reliability and transmission rate. In such propagation conditions, the Direct-Sequence Spread Spectrum (DSSS) method is one of the solutions that make reliable data transmission possible. In systems with one-to-one communication, it ensures communication with a satisfactory Bit Error Rat

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Kim, Gunzung, Imran Ashraf, Jeongsook Eom, and Yongwan Park. "Optimal Path Configuration with Coded Laser Pilots for Charging Electric Vehicles Using High Intensity Laser Power Beams." Applied Sciences 11, no. 9 (2021): 3826. http://dx.doi.org/10.3390/app11093826.

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Wireless power transmission (WPT) for wireless charging has been gaining wide attention as a promising approach to miniaturizing the battery size and increasing the maximal total range of an electric vehicle (EV). With an appropriate charging infrastructure, WPT holds great potential to accelerate the acceptance of EVs through users’ higher satisfaction, reducing EV cost, and increasing the driving range and capability. A WPT system based on high-intensity laser power beaming (HILPB) provides an optimal solution for wirelessly charging electric vehicles from a distance of several meters. Despi

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Kim, Taeyoon, Jeffrey G. Andrews, Jaeweon Kim, and Theodore S. Rappaport. "Multi-code Multicarrier CDMA: Performance Analysis." Journal of Communications Software and Systems 2, no. 1 (2017): 12. http://dx.doi.org/10.24138/jcomss.v2i1.301.

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A new multi-code multicarrier code division multiple access (MC-MC-CDMA) system is proposed and analyzed in afrequency selective fading channel. By allowing each user to transmit an M-ary code sequence, the proposed MC-MC-CDMA system can support various data rates as required by next generation standards without increasing the interference which is common in general multicarrier CDMA systems. The bit error rate of the system is analytically derived in frequency selective fading, with Gaussian noise and multiple access interference. The results show that the proposed MC-MC-CDMA system clearly o

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Taubin, F. A. "MULTIPLE ACCESS IN WIRELESS CHANNELS USING NONORTHOGONAL CODING AND FREQUENCY INTERLEAVING." System analysis and logistics 4, no. 34 (2022): 73–82. http://dx.doi.org/10.31799/2077-5687-2022-4-73-82.

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Code division multiple access (CDMA) is currently considered as one of the promising technologies that can significantly improve the efficiency of modern and future communication networks. In code division multiple access systems, users can share a dedicated space-frequency-time resource to simultaneously transmit their own traffic. To ensure the separation of individual user streams on the receiving side, each user is provided with his own code sequence embedded in the broadband signal transmitted by this user, the spectrum of which, as a rule, occupies the entire allocated frequency band. Wh

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Suresh Babu, Sumith Babu, and R. Kumar. "Multigroup Synchronization in 1D-Bernoulli Chaotic Collaborative CDMA." Wireless Communications and Mobile Computing 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/7561757.

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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 secu

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Yen, Chih-Ta, Ing-Jr Ding, and Cheng-Mu Tsai. "PERFORMANCE ANALYSIS OF SEVERAL QUASI-ORTHOGONAL CODES OPTICAL CDMA FOR RADIO-OVER-FIBER SYSTEM." Transactions of the Canadian Society for Mechanical Engineering 37, no. 3 (2013): 415–26. http://dx.doi.org/10.1139/tcsme-2013-0031.

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An optical code-division multiple-access (OCDMA) network for radio-over-fiber (RoF) transmissions was proposed. The network encoders/decoders (codecs) were structured based on arrayed-waveguide-grating (AWG) routers coded using modified prime codes (MPCs). In the proposed system, the lower in-phase cross correlation could reduce the beating noise, and in the proposed study, its performance was compared with that of a conventional system that uses M-sequence and Walsh-Hadamard codes. The performance of both systems was numerically evaluated by analyzing the effect of phase-induced-intensity noi

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Zhang, Zhen Yu, Feng Chun Tian, Fan Xin Zeng, Li Jia Ge, and Gui Xin Xuan. "Symbol Timing Sequence Structure for OFDM-CDMA Communication System under Low SNR." Applied Mechanics and Materials 713-715 (January 2015): 1188–92. http://dx.doi.org/10.4028/www.scientific.net/amm.713-715.1188.

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Symbol synchronization offset of orthogonal frequency division multiplexing (OFDM) communication system will cause the rotation of data constellation at receiver even if such offset falls in the range of the appended cyclic prefix. When OFDM modulation is combined with spread spectrum technique, e.g., OFDM code division multiple access (OFDM-CDMA), the problem becomes more serious since OFDM-CDMA communication system generally works under very low signal-to-noise ratio. This paper focuses on symbol timing synchronization of OFDM-CDMA communication system and proposes an effective sequence stru

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Mrabet, Hichem. "A Performance Analysis of a Hybrid OCDMA-PON Configuration Based on IM/DD Fast-OFDM Technique for Access Network." Applied Sciences 10, no. 21 (2020): 7690. http://dx.doi.org/10.3390/app10217690.

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The purpose of this article is to propose a new configuration based on OCDMA and Fast-OFDM techniques for access network applications. A hybrid intensity modulation with direct detection, fast orthogonal frequency-division multiplexing–code division multiplexing access (IM/DD Fast-OFDM-CDMA) system is analytically and numerically evaluated for an amplifier-free access network. Therefore, system performance is analytically investigated in terms of bit error rate/Q-factor as a function of simultaneous users, fiber length and launched optical power. Firstly, the proposed analytical model includes

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Liu, Peng. "A New Congestion Control Algorithm of CDMA Systems." Advanced Materials Research 255-260 (May 2011): 2220–23. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.2220.

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A new congestion control algorithm of code division multiple access (CDMA) is developed to reduce the cost of system. Firstly,the paper defines the utility function of resource throughout,and then set up the mathematics model according to the wireless resource characteristic. In the approach only the non-linear compensating term, solution of a sequence of adjoint vector differential equations, is required iteration. By taking the finite iteration of non-linear compensating term of optimal solution sequence, a suboptimal congestion control algorithm of CDMA can be obtained. It is proved by anal

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Wang, Xin, and Jari Nurmi. "Comparison of a Ring On-Chip Network and a Code-Division Multiple-Access On-Chip Network." VLSI Design 2007 (April 5, 2007): 1–14. http://dx.doi.org/10.1155/2007/18372.

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Two network-on-chip (NoC) designs are examined and compared in this paper. One design applies a bidirectional ring connection scheme, while the other design applies a code-division multiple-access (CDMA) connection scheme. Both of the designs apply globally asynchronous locally synchronous (GALS) scheme in order to deal with the issue of transferring data in a multiple-clock-domain environment of an on-chip system. The two NoC designs are compared with each other by their network structures, data transfer principles, network node structures, and their asynchronous designs. Both the synchronous

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Alshammari, A. S. "Synchronization of Two Chaotic Stream Ciphers in Secure CDMA Communication Systems." Engineering, Technology & Applied Science Research 10, no. 4 (2020): 5947–52. http://dx.doi.org/10.48084/etasr.3569.

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In the basic processing of Code Division Multiple Access (CDMA) systems using chaotic code sequences, a pair of chaos generators in the transmitter and the receiver are used to generate the same sequence, in order to synchronize and retrieve the transmitted signals. In addition, a filter with a simple structure should be integrated into chaotic signals to achieve the maximum of the signal to noise ratio and mitigate the harmful effects of multipath. Another effective property of chaos signal is that a wireless multipath channel does not change the amount of contained information. Considering t

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YONG, REN, YONGXIANG XIA, XIUMING SHAN, and YUAN JIAN. "DRIVING SYNCHRONIZATION OF SPATIOTEMPORAL CHAOS AND ITS APPLICATIONS IN CDMA COMMUNICATIONS." International Journal of Bifurcation and Chaos 11, no. 12 (2001): 3117–24. http://dx.doi.org/10.1142/s0218127401004042.

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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 syste

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Plascencia, Emmanuel, Oyunchimeg Shagdar, Hongyu Guan, Olivier Barrois, and Luc Chassagne. "Optical CDMA MAC Evaluation in Vehicle-to-Vehicle Visible Light Communications." Electronics 11, no. 9 (2022): 1454. http://dx.doi.org/10.3390/electronics11091454.

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One of the most critical challenges in vehicle-to-vehicle (V2V) visible light communications (VLCs) is the access capability of multi-users over the same channel. VLC links are known to be line of sight (LOS) and highly directional compared to the commonly used radio-frequency (RF) technologies, but multi-user interference can still be problematic. Consequently, it is necessary to develop a medium access control (MAC) protocol for VLC. In the present work, we propose a novel optical code division multiple access (OCDMA) protocol. The fundamentals of the VLC channel are presented, and the inter

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