Xiukai Ruan¹, Shahid Iqbal Awan^2,*

Journal on Internet of Things, Vol.4, No.4, pp. 215-225, 2022, DOI:10.32604/jiot.2022.038270

Abstract A SCMA ACO-OFDM downlink visible light communication (VLC) system is proposed. Six users share four spectrum resources, four of which are 4 primary color LED lights. ACO-OFDM technology is used to convert the user’s sparse codebook mapped signal into a positive real value signal that can be carried on the light wave, which can realize high-speed parallel communication. Simulation verifies the feasibility of the system. At the same time, the channel model of visible light communication is constructed, and the signal-to-noise ratio(SNR) and channel gain of the visible light channel are systematically analyzed. Finally, the theoretical bit error rate formula… More >

G. Rajamanickam^1,*, G. Ravi²

Intelligent Automation & Soft Computing, Vol.35, No.3, pp. 3037-3048, 2023, DOI:10.32604/iasc.2023.029996

Abstract The sparse code multiple access (SCMA) scheme is a Non-Orthogonal Multiple Access (NOMA) type of scheme that is used to handle the uplink component of mobile communication in the current generation. A need of the 5G mobile network is the ability to handle more users. To accommodate this, the SCMA allows each user to deploy a variety of sub-carrier broadcasts, and several consumers may contribute to the same frequency using superposition coding. The SCMA approach, together with codebook design for each user, is used to improve channel efficiency through better management of the available spectrum. However, developing a codebook with… More >

Xiaohong Ji¹, Junjun Du¹, Guoqing Jia^1,*, Weidong Fang^2,3

Intelligent Automation & Soft Computing, Vol.27, No.3, pp. 737-746, 2021, DOI:10.32604/iasc.2021.013009

Abstract As a new non-orthogonal multiple access technology for 5G massive machine type communication scenario, the sparse code multiple access (SCMA) has greatly improved the spectrum efficiency due to the high connection density. SCMA combines QAM (Quadrature Amplitude Modulation) modulation and sparse spreading into a codebook set to obtain forming gain. The user binary bit data is directly mapped into multi-dimensional codewords in the transmitter. The receiver uses the message passing algorithm (MPA) for multi-user detection to achieve efficient decoding. However, MPA is a good solution for SCMA, though its high complexity limits the application in practical systems. In order to… More >

Xiaohong Ji¹, Junjun Du¹, Guoqing Jia^1,*, Weidong Fang^2,3

Intelligent Automation & Soft Computing, Vol.27, No.1, pp. 221-231, 2021, DOI:10.32604/iasc.2021.013145

Abstract Sparse code multiple access (SCMA) is a new non-orthogonal multiple access scheme suitable for 5G communication, which can effectively improve spectrum efficiency and support massive connections. Multiple users in the SCMA system realize the sharing of the same time-frequency resources by mapping data into codewords of a special code book (Code Book, CB). A typical SCMA system increases the spectrum utilization to 150%. In order to further improve the system spectrum utilization and increase the number of user connections, this paper proposes an uplink SCMA codebook reuse transmission and reception scheme (CB-Reuse-SCMA), which reuse a codebook to multiple users. The… More >