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Enabling Sphere Decoding for SCMA

Vameghestahbanati, Monirosharieh, Mohamed, Ebrahim Bedeer, Marsland, Ian, Gohary, Ramy and Yanikomeroglu, Halim (2017) Enabling Sphere Decoding for SCMA. IEEE Communications Letters, 21 (12). pp. 2750-2753. [Journal article]

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DOI: 10.1109/LCOMM.2017.2747550


In this paper, we propose a reduced-complexity optimal modified sphere decoding (MSD) detection scheme for SCMA. As SCMA systems are characterized by a number of resource elements (REs) that are less than the number of the supported users, the channel matrix is rank-deficient, and sphere decoding (SD) cannot be directly applied. Inspired by the Tikhonov regularization, we formulate a new full-rank detection problem that it is equivalent to the original rank-deficient detection problem for constellation points with constant modulus and an important subset of non-constant modulus constellations. By exploiting the SCMA structure, the computational complexity of MSD is reduced compared with the conventional SD. We also employ list MSD to facilitate channel coding. Simulation results demonstrate that in uncoded SCMA systems the proposed MSD achieves the performance of the optimal maximum likelihood (ML) detection. Additionally, the proposed MSD benefits from a lower average complexity compared with MPA.

Item Type:Journal article
Keywords:Sparse code multiple access (SCMA), modified list sphere decoding (MSD), maximum likelihood (ML)
Faculties and Schools:Faculty of Computing & Engineering
Faculty of Computing & Engineering > School of Engineering
ID Code:38541
Deposited By: Dr Ebrahim Bedeer Mohamed
Deposited On:09 Feb 2018 11:49
Last Modified:09 Feb 2018 11:49

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