Performance Evaluation of Adaptive Non-contiguous MC-CDMA and Non-contiguous CI/MC-CDMA for Dynamic Spectrum Access

Wu, Zhiqiang; Ratazzi, E. Paul; Chakravarthy, Vasu; Hong, Lang

doi:10.1109/crowncom.2008.4562551

Cited by 18 publications

(20 citation statements)

References 8 publications

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“…the available number of the sub-carriers is dynamic. Therefore, in the real application, the selfadaptive method [5] can be employed to construct the NCI and NPCI codes with variable length, which further yields the adaptive NCI-OFDM and NPCI-OFDM systems. Different non-contiguous systems based on NC-CI have been discussed in following subsections.…”

Section: Related Work On Non-contiguous CI Codesmentioning

confidence: 99%

“…For better utilization of spectrum, CR need to transmit over multiple non-contiguous frequency holes. To achieve this objective, the Physical Layer architecture (PHY) must be highly flexible and adaptable [5].…”

Section: Introductionmentioning

confidence: 99%

“…Non-contiguous spectrum access schemes based on NC-CI codes have been considered strong candidates for CR and DSA [21], [22]. It has been pointed out in [5] that the performance of adaptive NC-CI/MC-CDMA outperforms adaptive NC-multicarrier code division multiple access (NC-MC/CDMA) using Hadamard-Walsh codes. Also, by applying non-contiguous spread orthogonal frequency division multiplexing (NC-SOFDM) with CI code, the loss of orthogonality among spreading codes caused by deactivating subcarriers can be eliminated [21], [22] in DSA.…”

Section: Introductionmentioning

confidence: 99%

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A study on Non-contiguous Carrier Interferometry code for Cognitive Radio

Mukherjee

Kumar

Matam

2015

2015 International Conference on Communications, Signal Processing, and Their Applications (ICCSPA'15)

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Non-contiguous Carrier Interferometry (NC-CI) signature waveforms have been proposed for Dynamic Spectrum Access (DSA) and Cognitive Radio (CR) system in the literature. Walsh-Hadamard (WH) codes cannot ensure orthogonality for non-contiguous carrier allocation, when the number of noncontiguous carrier is not a multiple of 4. In literature, NC-CI and binary orthogonal codes of any code length are proposed for non-contiguous spectrum allocation. In this paper the crosscorrelation properties of NC-CI signature waveforms for noncontiguous CI orthogonal frequency division multiplexing (NC-CI/OFDM) and NC-CI multicarrier code division multiple access (NC-CI/MC-CDMA) have been evaluated through simulation and analysis over AWGN channel. Time domain NC-CI waveforms have also been examined for non-contiguous allocation. Crosscorrelation analysis and time domain waveforms show that NC-CI codes maintain orthogonality over non-contiguous subcarrier allocation in single user and multiuser environments. For WH code, it has been shown that orthogonality can be maintained with a loss of data rate.

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Section: Related Work On Non-contiguous CI Codesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A study on Non-contiguous Carrier Interferometry code for Cognitive Radio

Mukherjee

Kumar

Matam

2015

2015 International Conference on Communications, Signal Processing, and Their Applications (ICCSPA'15)

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“…To meet the wireless portion of the network the researchers currently concentrated at physical layer and data-link layer to speedup the data transfer and power saving [3,8,9,11,17].…”

Section: Problems In the Current Designmentioning

confidence: 99%

“…More research is needed before any successful attempt of cross-layer design can be completed. The references [9,[17][18][19][20] provide the recent work on cross-layer design and cognitive networks.…”

Section: Future Researchmentioning

confidence: 99%

Cross-Layer Design Approach for Wireless Networks to Improve the Performance

Smith

Reddy

Gajendar

2009

2009 Sixth International Conference on Information Technology: New Generations

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Future wireless networks will be loaded with voice, messaging, file transferring, multimedia teleconferencing, games, and Web browsing. With the increasing traffic and real time demand the current status of networking cannot meet the demands of future wireless applications. Traffic will be jammed on current wireless channels and customers will enter into a deadlock situation. Therefore, new models and approaches are required to meet the customer demands. But, it is a known fact that the available spectrum is sold out and currently used in static mode. Therefore the emergence of next generation wireless technologies will enhance the effectiveness of the existing methods. One of the possible approaches will be allocating the spectrum dynamically by developing new algorithms and protocols. Another way is Cross-layer approach which helps in efficient allocation of spectrum to eliminate the jamming problem. In this review, we discuss some of the recent developments in literature on cross-layer aspects and its effect on the allocation of spectrum to meet the customer demands.

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A novel multicarrier CDMA transmission scheme for cognitive radios with sidelobe suppression

Rajabzadeh

Khoshbin

2012

Int J Communication

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SUMMARYNoncontiguous multicarrier code division multiple access (MC‐CDMA) is an effective multiple access method for cognitive radio systems that can deploy the noncontiguous vacant parts of a certain spectrum shared with the users of a primary system. However, the large spectral sidelobes of the Fourier transform based implementation of the MC‐CDMA interfere with the adjacent primary transmission. In this paper, a novel complex signature sequence set is proposed for synchronous downlink MC‐CDMA based cognitive radio networks to suppress the sidelobes. To do so, the minimization of the sidelobes power is developed as an eigen‐optimization problem that is optimally solved by using the eigenvalue decomposition method. The optimal complex signature sequences are chosen as the eigenvectors attained by the eigenvalue decomposition of a symmetric matrix that is dependent of the spectral characteristics of the primary users. Simulation results show that by a slight decrease in the maximum number of active users compared with full load, the sidelobes can be considerably suppressed. The effect of cyclic prefix length, the bandwidth of the primary system and the number of active users on the sidelobe suppression performance is analyzed through numerical simulations. Copyright © 2012 John Wiley & Sons, Ltd.

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Performance Evaluation of Adaptive Non-contiguous MC-CDMA and Non-contiguous CI/MC-CDMA for Dynamic Spectrum Access

Cited by 18 publications

References 8 publications

A study on Non-contiguous Carrier Interferometry code for Cognitive Radio

A study on Non-contiguous Carrier Interferometry code for Cognitive Radio

Cross-Layer Design Approach for Wireless Networks to Improve the Performance

A novel multicarrier CDMA transmission scheme for cognitive radios with sidelobe suppression

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