TY - JOUR
T1 - An Efficient SCMA Codebook Design Based on Lattice Theory for Information-Centric IoT
AU - Zhang, Xuewan
AU - Han, Gangtao
AU - Zhang, Dalong
AU - Zhang, Di
AU - Yang, Liuqing
N1 - Funding Information:
This work was supported in part by the Natural Science and Technology Major Projects of China under Grant 2017ZX03001001-004, and in part by the Zhengzhou University Startup Foundation under Grant 32210907 and Grant 32211247.
Publisher Copyright:
© 2013 IEEE.
PY - 2019
Y1 - 2019
N2 - Different from traditional communication systems, information-centric Internet of things (IC-IoT) as a novel smart paradigm needs to guarantee end-to-end connectivity for rapidly growing smart devices. How to meet the demands of massive connection has become a key problem for IC-IoT. Sparse code multiple access (SCMA) as a code-domain non-orthogonal multiple access (NOMA) technique has been intensively investigated. With SCMA, each user employs different sub-carrier frequencies for transmission, and different users can share the same sub-carrier frequency via superposition coding. The spectrum efficiency is thus improved. However, designing large-scale codebook sets is still an open problem for SCMA. In this paper, a new lattice-based codebook design method is proposed via mother constellation optimization. First, the optimization problem of the mother constellation is formulated. Through analysis, the problem can be converted into two sub-problems. Accordingly, we first use the lattice theory to find a constellation containing infinite points with large coding gain. After that, we search for a boundary that contains a set of points via spherical packing. Such an approach enables us to obtain a real constellation satisfying a power saving criterion. Secondly, the mother constellation with large power variance is obtained from the real multi-dimensional constellation. Finally, lattice-based codebooks are generated by combining the mother constellation and the mapping matrices with constellation rotation. Simulations demonstrate that the designed codebooks have improved bit error rate (BER) performance with large codebook size, especially at high signal to noise ratio (SNR).
AB - Different from traditional communication systems, information-centric Internet of things (IC-IoT) as a novel smart paradigm needs to guarantee end-to-end connectivity for rapidly growing smart devices. How to meet the demands of massive connection has become a key problem for IC-IoT. Sparse code multiple access (SCMA) as a code-domain non-orthogonal multiple access (NOMA) technique has been intensively investigated. With SCMA, each user employs different sub-carrier frequencies for transmission, and different users can share the same sub-carrier frequency via superposition coding. The spectrum efficiency is thus improved. However, designing large-scale codebook sets is still an open problem for SCMA. In this paper, a new lattice-based codebook design method is proposed via mother constellation optimization. First, the optimization problem of the mother constellation is formulated. Through analysis, the problem can be converted into two sub-problems. Accordingly, we first use the lattice theory to find a constellation containing infinite points with large coding gain. After that, we search for a boundary that contains a set of points via spherical packing. Such an approach enables us to obtain a real constellation satisfying a power saving criterion. Secondly, the mother constellation with large power variance is obtained from the real multi-dimensional constellation. Finally, lattice-based codebooks are generated by combining the mother constellation and the mapping matrices with constellation rotation. Simulations demonstrate that the designed codebooks have improved bit error rate (BER) performance with large codebook size, especially at high signal to noise ratio (SNR).
KW - Information-centric Internet of Things (IC-IoT)
KW - lattice theory
KW - non-orthogonal multiple access (NOMA)
KW - sparse code multiple access (SCMA)
KW - spherical packing
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U2 - 10.1109/ACCESS.2019.2938637
DO - 10.1109/ACCESS.2019.2938637
M3 - Article
AN - SCOPUS:85077966231
VL - 7
SP - 133865
EP - 133875
JO - IEEE Access
JF - IEEE Access
SN - 2169-3536
M1 - 8821310
ER -