Deep Learning Based Modified Message Passing Algorithm for Sparse Code Multiple Access

Author(s):  
Lanping Li ◽  
Xiaohu Tang ◽  
Chintha Tellambura
2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Cheng Yan ◽  
Ningbo Zhang ◽  
Guixia Kang

For sparse code multiple access advanced (SCMAA), the quality of initial information on each resource node and the convergence reliability of the detected user in each decision process were unsatisfactory at the message passing algorithm (MPA) receiver. Driven by these problems, this paper proposes a nonuniform code multiple access (NCMA) scheme. In the codebook design of NCMA, different transmitted layers are generated from different complex multidimension constellations, respectively, and a novel basic complex multidimension constellation design is proposed to increase the minimum intrapartition distance. Then a novel criterion of permutation set is proposed to maximize the sum of distances between interfering dimensions of transmitted codewords multiplexed on any resource node, where the number of nonzero elements of transmitted codewords is more than 1. On the other side, an advanced MPA receiver is proposed to improve the reliability of detection on each transmitted layer of NCMA. Simulation results show that the block error rate performance of NCMA outperforms SCMAA and sparse code multiple access (SCMA) under the same spectral efficiency.


2020 ◽  
Vol 69 (4) ◽  
pp. 3562-3574 ◽  
Author(s):  
Chuan Zhang ◽  
Chao Yang ◽  
Xu Pang ◽  
Wenqing Song ◽  
Wei Xu ◽  
...  

2017 ◽  
Vol 66 (11) ◽  
pp. 9986-9999 ◽  
Author(s):  
Jincheng Dai ◽  
Kai Niu ◽  
Chao Dong ◽  
Jiaru Lin

Frequenz ◽  
2017 ◽  
Vol 71 (11-12) ◽  
Author(s):  
Jing Lei ◽  
Baoguo Li ◽  
Erbao Li ◽  
Zhenghui Gong

AbstractMultiple access via sparse graph, such as low density signature (LDS) and sparse code multiple access (SCMA), is a promising technique for future wireless communications. This survey presents an overview of the developments in this burgeoning field, including transmitter structures, extrinsic information transform (EXIT) chart analysis and comparisons with existing multiple access techniques. Such technique enables multiple access under overloaded conditions to achieve a satisfactory performance. Message passing algorithm is utilized for multi-user detection in the receiver, and structures of the sparse graph are illustrated in detail. Outlooks and challenges of this technique are also presented.


Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1016
Author(s):  
Guanghua Zhang ◽  
Zonglin Gu ◽  
Qiannan Zhao ◽  
Jingqiu Ren ◽  
Weidang Lu

Sparse Code Multiple Access (SCMA) technology is a new multiple access scheme based on non-orthogonal spread spectrum technology, which was proposed by Huawei in 2014. In the algorithm application of this technology, the original Message Passing Algorithm (MPA) has slow convergence speed and high algorithm complexity. The threshold-based MPA has a high Bit Error Ratio (BER) when the threshold is low. In the Maximum logarithm Message Passing Algorithm (Max-log-MPA), the approximation method is used, which will cause some messages to be lost and the detection performance to be poor. Therefore, in order to solve the above problems, a Threshold-Based Max-log-MPA (T-Max-log-MPA) low complexity multiuser detection algorithm is proposed in this paper. The Maximum logarithm (Max-log) algorithm is combined with threshold setting, and the stability of user nodes is considered as a necessary condition for decision in the algorithm. Before message updating, the user information nodes are judged whether the necessary conditions for the stability of the user node have been met, and then the threshold is determined. Only users who meet the threshold condition and pass the necessary condition of user node stability can be decoded in advance. In the whole process, the logarithm domain MPA algorithm is used to convert an exp operation and a multiplication operation into a maximum value and addition operation. The simulation results show that the proposed algorithm can effectively reduce the computational complexity while ensuring the BER, and with the increase of signal-to-noise ratio, the effect of the Computational Complexity Reduction Ratio (CCRR) is more obvious.


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