Performance analysis for synchronous OFDM-CDMA with joint frequency-time spreading

Zheng, Kan; Zeng, Guoyan; Lei, Lei; Wang, Wenbo

doi:10.1109/icc.2004.1313157

Cited by 6 publications

(4 citation statements)

References 7 publications

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“…1-D OFDM-CDMA has been investigated extensively in the literature including receiver design, and performance evaluation and comparisons between different spreading methods, see [1,2] and references therein. 2-D OFDM-CDMA, where data symbols are spread both in time and frequency domains, has been getting more and more attention recently because of its ability to exploit temporal and spectral characteristics of the fading channels [3,4].…”

Section: Introductionmentioning

confidence: 99%

Transmitter-Based Pre-Processing for OFDM-CDMA Forward-Link Systems with Two-Dimensional Spreading

Kuo

Sheen

Chang

et al. 2006

IEEE Vehicular Technology Conference

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Transmitter-based signal pre-processing is investigated for the two-dimensional (2-D) OFDM-CDMA (orthogonal frequency division multiplexing, code division multiple access) forward link systems, aiming to increase the system sum-capacity and shift the signal processing complexity of a mobile unit to the base station. For the non-selective fading channels, the optimum pre-processing that achieves the maximum ergodic sum-capacity is obtained by applying the principle of multi-user water filling under the condition of zero multiple access interference (MAI). For the selective fading channels, on the other hand, three sub-optimum methods including ZF (zero-forcing) with power normalization, MMSE (minimum mean square error), and the newly proposed ZF with multi-user water filling are investigated under the constraint of total transmit power. Numerical results show that: (i) The new pre-processing outperforms the traditional other two in terms of achievable sum-capacity. (ii) 2-D spreading pattern should be adapted to the channel conditions so as to minimize MAI and thus maximize the sum-capacity. In this regard, 2-D spreading has advantage over the 1-D one. (iii) The fewer the users scheduled at a time, the higher the system capacity; a result obtained from exploiting the multi-user diversity.Index Terms-OFDM-CDMA, sum-capacity, transmitter signal pre-processing, forward link systems.

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Section: Introductionmentioning

confidence: 99%

Transmitter-Based Pre-Processing for OFDM-CDMA Forward-Link Systems with Two-Dimensional Spreading

Kuo

Sheen

Chang

et al. 2006

IEEE Vehicular Technology Conference

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show abstract

“…One of them, the extension of OFDMA with code division multiplexing (CDM) [3], is a promising candidate as a multiple access scheme for the uplink, which can cope with a certain amount of asynchronism. It applies OFDMA for user separation and additionally uses CDM on data symbols belonging to the same user.…”

Section: Introductionmentioning

confidence: 99%

“…Since the users are distinguished by an FDMA scheme, the signals of the desired users can be easily filtered according to (3) and no interference between users exists under the assumption of ideal synchronization. Without the loss of generality, only the signal of the 0th user is analyzed and the user index is omitted in the following part (e.g.SO can be expressed as S).…”

Section: Introductionmentioning

confidence: 99%

“…Various OFDM-CDMA schemes have been proposed and drawn a lot of interests in the research area of the future broadband mobile communication systems[l] [2] [3]. One of them, the extension of OFDMA with code division multiplexing (CDM) [3], is a promising candidate as a multiple access scheme for the uplink, which can cope with a certain amount of asynchronism.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Improved V-BLAST Receiver for Uplink CDM-OFDMA

Zheng

Zhao

Wang

et al.

2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications

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This paper proposes a novel detection algorithm for multiple-input multiple-out (MIMO) Code division multiplexOrthogonal Frequency division multiplex access (CDM-OFDMA) system in the uplink. Vertical Bell Laboratories Layered SpaceTime (V-BLAST) detection is processed only after despread-. ing/combining at the receiver, which not only achieves good MOD Spreading Interleaving frequency diversity gain but also has low implementation com&Mapping plexity. Parallel interference cancellation (PIC) algorithm can also be applied to improve the performance of systems with heavy loads. Computer simulation demonstrates effectiveness of this detector and conclusion is followed.

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Performance comparison of interleaving methods in joint frequency-time spreading OFDM-CDMA

Zheng

Gai

Zeng

et al. 2004

2004 International Conference on Communications, Circuits and Systems (IEEE Cat. No.04EX914)

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Performance analysis for synchronous OFDM-CDMA with joint frequency-time spreading

Cited by 6 publications

References 7 publications

Transmitter-Based Pre-Processing for OFDM-CDMA Forward-Link Systems with Two-Dimensional Spreading

Transmitter-Based Pre-Processing for OFDM-CDMA Forward-Link Systems with Two-Dimensional Spreading

Improved V-BLAST Receiver for Uplink CDM-OFDMA

Performance comparison of interleaving methods in joint frequency-time spreading OFDM-CDMA

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