Hybrid Rate-Splitting and Sparse Code Multiple Access (RS-SCMA): Design and Performance
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| Main Authors: | , , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866915758205829120 |
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| author | Priyadarsini, Minerva Liu, Zilong Deka, Kuntal Sahoo, Sujit Kumar Sharma, Sanjeev |
| author_facet | Priyadarsini, Minerva Liu, Zilong Deka, Kuntal Sahoo, Sujit Kumar Sharma, Sanjeev |
| contents | This paper proposes, for the first time, a hybrid multiple access framework that integrates the principles of rate-splitting (RS) and sparse code multiple access (SCMA) in an SISO downlink scenario. The proposed scheme, termed RS-SCMA, unifies the powerful interference management capability of rate-splitting multiple access (RSMA) with the near-optimal multiuser detection of SCMA. A key feature of RS-SCMA is a tunable splitting factor $α$, which governs the allocation between the generic $M$-ary modulated common messages and SCMA-encoded private messages. This enables dynamic control over the fundamental trade-off between system sum-rate, bit error rate (BER), and the overloading factor. We develop novel transmitter and receiver architectures based on soft successive interference cancellation (SIC), incorporating message passing algorithm (MPA) detection and soft-symbol reconstruction. Furthermore, a unified analytical expression for the achievable sum-rate is derived as a function of the splitting factor $α$. The performance of the proposed RS-SCMA system is evaluated in terms of both BER and sum-rate. Simulation results confirm the superiority of RS-SCMA over conventional SCMA and multi-carrier RSMA, demonstrating its scalability and robustness even in the presence of channel estimation errors. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2501_15412 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Hybrid Rate-Splitting and Sparse Code Multiple Access (RS-SCMA): Design and Performance Priyadarsini, Minerva Liu, Zilong Deka, Kuntal Sahoo, Sujit Kumar Sharma, Sanjeev Signal Processing This paper proposes, for the first time, a hybrid multiple access framework that integrates the principles of rate-splitting (RS) and sparse code multiple access (SCMA) in an SISO downlink scenario. The proposed scheme, termed RS-SCMA, unifies the powerful interference management capability of rate-splitting multiple access (RSMA) with the near-optimal multiuser detection of SCMA. A key feature of RS-SCMA is a tunable splitting factor $α$, which governs the allocation between the generic $M$-ary modulated common messages and SCMA-encoded private messages. This enables dynamic control over the fundamental trade-off between system sum-rate, bit error rate (BER), and the overloading factor. We develop novel transmitter and receiver architectures based on soft successive interference cancellation (SIC), incorporating message passing algorithm (MPA) detection and soft-symbol reconstruction. Furthermore, a unified analytical expression for the achievable sum-rate is derived as a function of the splitting factor $α$. The performance of the proposed RS-SCMA system is evaluated in terms of both BER and sum-rate. Simulation results confirm the superiority of RS-SCMA over conventional SCMA and multi-carrier RSMA, demonstrating its scalability and robustness even in the presence of channel estimation errors. |
| title | Hybrid Rate-Splitting and Sparse Code Multiple Access (RS-SCMA): Design and Performance |
| topic | Signal Processing |
| url | https://arxiv.org/abs/2501.15412 |