Convolutional Multi-Code Multiplexing for OFDM Systems

Jiang, Wei; Li, Daoben

doi:10.1109/icc.2007.805

Cited by 9 publications

(8 citation statements)

References 13 publications

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“…In [7], M i is equal to 2 only. Because each user's spreading encoder is a one input one output convolutional encoder, the coding rate for user i is defined by:…”

Section: A Time-varying Convolutional Spreading Encodermentioning

confidence: 97%

“…Moreover, the question that whether or not the spreading code dedicated to M-ary (M>2) modulation exist is not answered explicitly in [7]. To solve such problem, both upper bounds on node error and symbol error probability of OVCDMA in Gaussian multiple access channel are given in this paper by using random coding scheme.…”

Section: Introductionmentioning

confidence: 97%

“…But in [7], the spreading code is only dedicated to binary modulation (BPSK), because if the spreading encoder input in [7] is QPSK signal, the free Euclidean distance of the spreading encoder output is zero, i.e., reliable communication can hardly be guaranteed. Moreover, the question that whether or not the spreading code dedicated to M-ary (M>2) modulation exist is not answered explicitly in [7].…”

Section: Introductionmentioning

confidence: 99%

“…In [7], an overlapped code division multiple access (OVCDMA) communication scheme was proposed, in which each user's data symbols were passed through a unique rate-one weighted convolutional encoder and added together for simultaneous transmission. The weighted vector in each user's convolutional encoder is called a spreading code.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Overlapped Code Division Multiple Access System in Gaussian Multiple Access Channel

Yang

Jiang

et al. 2008

2008 IEEE International Conference on Communications

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This paper proposes an overlapped code division multiple access (OVCDMA) system where each user is assigned a unique convolutional spreading code and all the users access the channel simultaneously. Node error probability and symbol error probability upper bounds of OVCDMA in Gaussian multiple access channel are derived based on the random coding arguments. The former one ensures the existence of convolutional spreading code dedicated to M-ary (M>2) modulation and the later one is tight for moderate signal-to-noise ratio. In addition, the random coding simulation results show that the symbol error rate gets lower by increasing the convolutional spreading code length. Finally, several convolutional spreading codes dedicated to QPSK are found by random coding search and free Euclidean distance calculation. They are compared with conventional modulation scheme under the condition of same spectral efficiency. Simulations for these fixed convolutional spreading codes show that notable coding gain are achieved in Gaussian multiple access channel.

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“…In [7], M i is equal to 2 only. Because each user's spreading encoder is a one input one output convolutional encoder, the coding rate for user i is defined by:…”

Section: A Time-varying Convolutional Spreading Encodermentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Analysis of Overlapped Code Division Multiple Access System in Gaussian Multiple Access Channel

Yang

Jiang

et al. 2008

2008 IEEE International Conference on Communications

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“…But a trade-off between the diversity gain and spectral efficiency has to be made. Jiang and Li [6] [7] proposed the method of convolutional spreader to achieve diversity gain without loss of spectrum efficiency for multicarrier systems. But there is no coding gain with that method.…”

Section: Introductionmentioning

confidence: 99%

Near optimum Sequence Detection for coded OFDM-CMM systems

Jiang

2008

2008 Third International Conference on Communications and Networking in China

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Orthogonal Frequency Division Multiplexing Convolutional Multi-code Multiplexing (OFDM-CMM) has been proposed to achieve notable coding gain and diversity without loss of spectral efficiency. However, the complexity of Maximum Likelihood Sequence Estimation (MLSE) grows exponentially in the number of parallel streams. This detection algorithm is prohibitive when the number of parallel streams is large. The Interference Cancellation based Sequence Detection (ICSD) is proposed in this paper to reduce the detection complexity without performance loss. The heart of this method is to combine the interference cancellation and the MLSE into one iteration. The complexity of ICSD grows linearly in the number of parallel streams. The simulation results have shown that the proposed method can efficiently approximate the optimum MAP performance at a moderate Signal to Noise Ratio (SNR) in coded OFDM-CMM systems.

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