{"title":"TechRxiv: Share Your Preprint Research With the World!","authors":"","doi":"10.1109/JSSC.2025.3574898","DOIUrl":"https://doi.org/10.1109/JSSC.2025.3574898","url":null,"abstract":"","PeriodicalId":13129,"journal":{"name":"IEEE Journal of Solid-state Circuits","volume":"60 7","pages":"2671-2671"},"PeriodicalIF":4.6,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11071400","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144557927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Evangelos Dikopoulos;Luke Wormald;Ying-Tuan Hsu;Wei Tang;Po-Shao Chen;Zhengya Zhang;Michael P. Flynn
{"title":"RXO-LDPC: A Physics-Inspired Relaxation Oscillator-Based Solver Leveraging Six-Body Spin Interactions for Soft Decoding of LDPC Codes","authors":"Evangelos Dikopoulos;Luke Wormald;Ying-Tuan Hsu;Wei Tang;Po-Shao Chen;Zhengya Zhang;Michael P. Flynn","doi":"10.1109/JSSC.2025.3561780","DOIUrl":"10.1109/JSSC.2025.3561780","url":null,"abstract":"Physics-inspired computing harnesses continuous-time (CT) operation, massive parallelism, and direct compute load mapping to coupled CMOS-based spins to accelerate solving complex optimization problems. This work advances the field by introducing relaxation oscillator (RXO)-low-density parity check (LDPC), a combinatorial optimization problem (COP) engine that natively supports six-body spin interactions for efficient, robust, and one-shot oscillator-based soft decoding of LDPC codes. The proposed RXO spins feature a capacitor-DAC-based initialization structure, allowing precise mapping of soft information to initial spin phases for high-performance decoding. A crossbar-based feedback system facilitates six-body spin interactions by directly coupling spins based on the COP graph. Implemented in 28-nm CMOS technology, the prototype achieves a frame error rate (FER) and bit error rate (BER) of <inline-formula> <tex-math>$1.36{times }10{^{-6}}$ </tex-math></inline-formula> and <inline-formula> <tex-math>$1.89{times }10{^{-7}}$ </tex-math></inline-formula>, respectively, at 7-dB SNR. The measured BER is more than three orders of magnitude lower than for belief propagation (BP) decoding, for channels with 2–5-dB SNR. The measured energy efficiency of 7.28 pJ/bit exceeds the normalized efficiencies of state-of-the-art decoders. Evaluated with more than 100 million decoding cycles, the system demonstrates reliable performance across a wide range of SNRs, supply voltages, temperatures, and for different dies. These measurement results highlight the RXO-based architecture’s potential as an accelerator for directly solving COPs with multi-body spin interactions.","PeriodicalId":13129,"journal":{"name":"IEEE Journal of Solid-state Circuits","volume":"60 7","pages":"2420-2433"},"PeriodicalIF":4.6,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144500462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}