• Title/Summary/Keyword: multicarrier code-division multiple-access (MC-CDMA)

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Performance Analysis of Multicarrier Code Select CDMA System for PAPR Reduction in Multipath Channels

  • Ryu, Kwan-Woong;Jin, Jiyu;Park, Yong-Wan;Choi, Jeong-Hee
    • Journal of Communications and Networks
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    • v.11 no.1
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    • pp.11-19
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    • 2009
  • Multicarrier direct sequence code division multiple access (MC DS-CDMA) is an attractive technique for achieving high data rate transmission. This is valid regardless of whether or not the potentially large peak-to-average power ratio (PAPR) is an important factor for its application. On the other hand, code select CDMA (CS-CDMA) is an attractive technique with constant amplitude transmission of multicode signal regardless of subchannels. This is achieved by introducing a code select method. In this paper, we propose a new multiple access scheme based on the combination of MC DS-CDMA and CS-CDMA. The proposed scheme, which we call MC CS-CDMA, includes as special cases the subclasses of MC DS-CDMA and CS-CDMA. This paper investigates the performance of these systems over a multipath frequency selective fading channel using a RAKE receiver with maximal ratio combiner. In addition, the PAPR of the proposed system is compared with that of both MC DS-CDMA and CS-CDMA. Simulation results demonstrate that the proposed system provides better PAPR reduction than MC DS-CDMA, at the expense of the complexity of the receiver and the number of available users. The numerical result demonstrates that the proposed system has better performance than MC DS-CDMA due to the increased processing gain and time diversity gain.

Approximate Expression of Bit Error Rate in Uplink MC-CDMA Systems with Equal Gain Combining

  • Develi, Ibrahim;Akdagli, Ali
    • Journal of Communications and Networks
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    • v.15 no.1
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    • pp.25-30
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    • 2013
  • Uplink multicarrier code-division multiple-access (MC-CDMA) with equal gain combining (EGC) over Nakagami fading channels is considered. An improved expression which is a feasible alternative for the bit error rate (BER) performance evaluation of MC-CDMA signals is proposed. Simulated annealing algorithm is employed to obtain the optimum value of the coefficients belonging to the proposed expression. Numerical examples show that the performance curves computed by the improved expression are in good agreement with the results obtained by the exact expression. Thus, the proposed expression can improve the accuracy of BER performance evaluation that has been realized by the approximate expression.

Comparison and Analysis of the MC DS-CDMA/MPSK and DS-CDMA/MPSK Systems in Nakagami Fading (나카가미 감쇄에서 MC DS-CDMA/MPSK와 DS-CDMA/MPSK 시스템 비교 분석)

  • 이정도;강희조
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.6
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    • pp.951-958
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    • 1999
  • Multicarrier modulation or orthogonal frequency division multiplexing(OFDM) is a promising technique for mobile communications systems, since it has a strong immunity to multipath fading without employing complicated adaptive equalization. In this paper, performance of MC DS-CDMA/MPSK(multi-carrier direct sequence-code division multiple access/mary phase shift keying) and DS-CDMA/MPSK(direct sequence-code division multiple access/mary phase shift keying) with coherent detection for a CDMA system over Nakagami fading channel analysis. For a given bandwidth, it is shown that MC DS-CDMA/MPSK eventually outperforms DS-CDMA MPSK with random sequences.

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Performance Analysis of Dualrate MC-CDMA Systems Based on Code Grouping (코드그룹화에 의한 이중전송률 MC-CDMA 시스템의 성능분석)

  • Kim, Nam-Sun
    • Journal of Korea Society of Industrial Information Systems
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    • v.11 no.4
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    • pp.112-120
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    • 2006
  • Multicarrier code division multiple access(MC-CDMA) system that combines multicarrier modulation with CDMA offers robustness to frequency selective fading and can support higher rate data transmission with higher spectral efficiency. A new asynchronous MC-CDMA system to implement multiple data rate communications is proposed in this paper. In a W-CDMA downlink the orthogonal variable spreading factor(OVSF) code is used for variable spreading factor for various multimedia traffic. Proposed system utilizes the OVSF code that generated by generation property for spreading. The proposed MC-CDMA system use different lengths of OVSF code as a spreading code according to their data rate. The groupwise processing is accomplished by code grouping in OVSF code generation tree. For the analysis of average BER performance, numerical method and computer simulation were used. We also compare the system performance with that of a single rate MC-CDMA system used orthogonal code as a spreading code.

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Adaptive Resource Allocation for MC-CDMA and OFDMA in Reconfigurable Radio Systems

  • Choi, Yonghoon
    • ETRI Journal
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    • v.36 no.6
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    • pp.953-959
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    • 2014
  • This paper studies the uplink resource allocation for multiple radio access (MRA) in reconfigurable radio systems, where multiple-input and multiple-output (MIMO) multicarrier-code division multiple access (MC-CDMA) and MIMO orthogonal frequency-division multiple access (OFDMA) networks coexist. By assuming multi-radio user equipment with network-guided operation, the optimal resource allocation for MRA is analyzed as a cross-layer optimization framework with and without fairness consideration to maximize the uplink sum-rate capacity. Numerical results reveal that parallel MRA, which uses MC-CDMA and OFDMA networks concurrently, outperforms the performance of each MC-CDMA and OFDMA network by exploiting the multiuser selection diversity.

A Study on Adaptive Interference Suppressor for Multicarrier DS-CDMA (멀티캐리어 DS-CDMA를 위한 적응 간섭 억제기에 관한 연구)

  • 우대호;장병건;변윤식
    • Proceedings of the IEEK Conference
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    • 2000.09a
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    • pp.25-28
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    • 2000
  • In this paper, we choice multicarrier direct-sequence code division multiple access using bandwidth effectively in communication system. Because this system is based on DS-CDMA the same problem is raised. That is, the degradation of the performance is due to multiple access interference. To solve this problem, we proposed the blind adaptive receiver for MC DS-CDMA system. Simulation results show that the proposed blind receiver has more about 0.5(dB) value of SNR than conventional receiver.

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Performance Analysis of Multicarrier Code Selection CDMA System for PAPR Reduction in Multipath Fading Channel (PAPR을 줄이기 위한 Multicarrier Code Select CDMA시스템의 다중 경로 페이딩 채널에서 성능 분석)

  • Ryu Kwan Woong;Park Yong Wan;Hong Een Kee;Kim Myovng Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.12A
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    • pp.1319-1332
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    • 2004
  • Multicarrier direct sequence code-division multiple access CDMA(MC DS-CDMA) is an attractive technique for achieving high data rate transmission even if the potentially large peak-to-average power ratio(PAPR) is an important factor for its application. On the other hand, code select CDMA(CS-CDMA) is an attractive technique with constant amplitude transmission of multicode signal irregardless of subchannels by introducing code selection method. In this paper we propose a new multiple access scheme based on the combination of MC DS-CDMA and CS-CDMA. Proposed scheme, which we called MC CS-CDMA, includes the sutclasses of MC DS-CDMA and CS-CDMA as special cases. The performance of this system is investigated for multipath Sequency selective fading channel and maximal ratio combining with rake receiver. In addition the PAPR of proposed system is compare with that of both MC BS-CDMA and CS-CDMA. Simulation results show that proposed system improves PAPR reduction than MC DS-CDMA at the expense of the complexity of receiver and the number of available non. Also, the numerical result shows that the proposed system is better performance than MC DS-CDMA due to the increasing processing gain and the number of time diversity gain.

Application of Rate Compatible Punctured Turbo Coded Hybrid ARQ to MC-CDMA Mobile Radio

  • Garg, Deepshikha;Adachi, Fumiyuki
    • ETRI Journal
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    • v.26 no.5
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    • pp.405-412
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    • 2004
  • MC-CDMA, a multicarrier (MC) modulation scheme based on code division multiple access (CDMA), is the most likely candidate for the next generation of mobile radio communications. The rate compatible punctured turbo (RCPT) coded hybrid automatic repeat request (HARQ) has been found to give improved throughput performance in a direct sequence (DS) CDMA system. However, the extent to which the RCPT HARQ improves the throughput performance of an MC-CDMA system has not been fully understood. In this paper, we apply the RCPT HARQ to MC-CDMA and evaluate by computer simulations its performance in a frequency selective Rayleigh fading channel. We found that the performance of RCPT HARQ MC-CDMA is almost insensitive to channel characteristics. The performance can be drastically improved with receive diversity combined with space-time transmit diversity. In addition, the comparison of RCPT HARQ MC-CDMA, orthogonal frequency division multiplexing, and DS-CDMA shows that under similar conditions the throughput of MC-CDMA is the best in a frequency selective fading channel.

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Performance Analysis of Maximum Likelihood Joint Detection for MIMO MC-CDMA Systems (순방향 다중 안테나 MC-CDMA 시스템에서 Maximum Likelihood 합동 검파 성능 분석)

  • Kim, Young-Ju;Song, Hyoung-Joon;Hong, Dae-Sik
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.11
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    • pp.1-8
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    • 2008
  • In this paper, we analyze the symbol error rate (SER) performance of maximum likelihood (ML) joint detection in downlink multiple-input multiple-output (MIMO) multicarrier code division multiple access (MC-CDMA) systems by deriving a tight union bound on the symbol error rate (SER). The union bound for ML joint detection is utilized to demonstrate the performance of MIMO MC-CDMA systems quantitatively in multiuser and frequency selective Rayleigh fading environments. An analysis of the diversity order of the systems shows the effects of multiple users, spread subcarriers, and multiple antennas on the ML joint detection performance. Furthermore, the analysis shows that MIMO MC-CDMA systems without full loading can achieve more diversify than MIMO orthogonal frequency division multiplexing (OFDM) systems.

Performance Analysis of Dualrate MC-CDMA Systems Using Hybrid Interference Cancellation (하이브리드 간섭제거기법을 적용한 이중전송률 MC-CDMA 시스템의 성능분석)

  • Kim Nam-Sun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.3C
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    • pp.228-236
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    • 2006
  • A Multicarrier code division multiple access(MC-CDMA) is a scheme that combines multicarrier modulation with CDMA. It offers robustness to frequency selective fading effect and can support higher rate data transmission with higher spectral efficiency. The objective of this article is proposed and analyzed a new asynchronous MC-CDMA system with various kinds of data rates which employs a multiple access interference (MAI) canceller. The proposed multirate MC-CDMA system can be accomplished by changing the number of Parallel branch(P) according to their data rate and hybrid interference canceller(HIC) are used for MAI cancellation. We compare the performance of proposed system in terms of average bit error rate(BER) with that of a single rate MC-CDMA system. The results show the large improvement in performance that can be attained by the cancellation scheme under multipath environments.