An Over-the-Air Multi-User Convolutional Code for URLLC
URLLC applications impose stringent latency and reliability requirements, making its compliance challenging due to the inherent trade-off between them. These applications typically involve the exchange of small information blocks. Convolutional codes (CC) exhibit near-optimal performance when encodi...
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| Format: | Article |
| Language: | English |
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IEEE
2025-01-01
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| Series: | IEEE Open Journal of the Communications Society |
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| Online Access: | https://ieeexplore.ieee.org/document/11015616/ |
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| author | Rafael Santos Daniel Castanheira Adao Silva Atilio Gameiro |
| author_facet | Rafael Santos Daniel Castanheira Adao Silva Atilio Gameiro |
| author_sort | Rafael Santos |
| collection | DOAJ |
| description | URLLC applications impose stringent latency and reliability requirements, making its compliance challenging due to the inherent trade-off between them. These applications typically involve the exchange of small information blocks. Convolutional codes (CC) exhibit near-optimal performance when encoding short blocks. To enable packet-based transmissions, CCs require some kind of termination. A zero-terminated CC (ZTCC) enables efficient maximum likelihood (ML) decoding through the Viterbi algorithm, but suffers from a rate-loss particularly prominent in short blocks. A tail-biting CC (TBCC) avoids rate-loss but entails significantly higher ML decoding complexity. Despite the ZTCC having lower ML decoding complexity and similar error performance, TBCC has received preference by wireless standards, essentially due to ZTCC rate-loss. This work proposes a novel distributed multi-user ZTCC (MU-ZTCC) coding scheme, which eliminates rate-loss by encoding multiple physically separated users over-the-air. Local user data undergoes standard ZTCC encoding followed by multi-user encoding via over-the-air summation. Due to its zero termination, ML decoding of MU-ZTCC is accomplished with a single Viterbi execution. Simulation results show that MU-ZTCC approaches the performance of orthogonal transmissions as SNR increases, while increasing the transmission rate by up to 47% for the selected parameters. This scheme can be viewed as a non-orthogonal multiple access scheme, whose structure enables ML joint detection and decoding with the complexity of standard Viterbi algorithm. |
| format | Article |
| id | doaj-art-ac6965fc05524497a7769b2a2a869ecc |
| institution | DOAJ |
| issn | 2644-125X |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IEEE |
| record_format | Article |
| series | IEEE Open Journal of the Communications Society |
| spelling | doaj-art-ac6965fc05524497a7769b2a2a869ecc2025-08-20T03:21:34ZengIEEEIEEE Open Journal of the Communications Society2644-125X2025-01-0164718473010.1109/OJCOMS.2025.357343711015616An Over-the-Air Multi-User Convolutional Code for URLLCRafael Santos0https://orcid.org/0000-0002-0245-6576Daniel Castanheira1https://orcid.org/0000-0002-3858-2574Adao Silva2https://orcid.org/0000-0002-7008-6773Atilio Gameiro3https://orcid.org/0000-0003-1565-7921Instituto de Telecomunicações, Aveiro, PortugalInstituto de Telecomunicações, Aveiro, PortugalInstituto de Telecomunicações, Aveiro, PortugalInstituto de Telecomunicações, Aveiro, PortugalURLLC applications impose stringent latency and reliability requirements, making its compliance challenging due to the inherent trade-off between them. These applications typically involve the exchange of small information blocks. Convolutional codes (CC) exhibit near-optimal performance when encoding short blocks. To enable packet-based transmissions, CCs require some kind of termination. A zero-terminated CC (ZTCC) enables efficient maximum likelihood (ML) decoding through the Viterbi algorithm, but suffers from a rate-loss particularly prominent in short blocks. A tail-biting CC (TBCC) avoids rate-loss but entails significantly higher ML decoding complexity. Despite the ZTCC having lower ML decoding complexity and similar error performance, TBCC has received preference by wireless standards, essentially due to ZTCC rate-loss. This work proposes a novel distributed multi-user ZTCC (MU-ZTCC) coding scheme, which eliminates rate-loss by encoding multiple physically separated users over-the-air. Local user data undergoes standard ZTCC encoding followed by multi-user encoding via over-the-air summation. Due to its zero termination, ML decoding of MU-ZTCC is accomplished with a single Viterbi execution. Simulation results show that MU-ZTCC approaches the performance of orthogonal transmissions as SNR increases, while increasing the transmission rate by up to 47% for the selected parameters. This scheme can be viewed as a non-orthogonal multiple access scheme, whose structure enables ML joint detection and decoding with the complexity of standard Viterbi algorithm.https://ieeexplore.ieee.org/document/11015616/Ultra-reliable low-latency communicationschannel codingmulti-useruplinknon-orthogonal multiple accessmaximum likelihood decoding |
| spellingShingle | Rafael Santos Daniel Castanheira Adao Silva Atilio Gameiro An Over-the-Air Multi-User Convolutional Code for URLLC IEEE Open Journal of the Communications Society Ultra-reliable low-latency communications channel coding multi-user uplink non-orthogonal multiple access maximum likelihood decoding |
| title | An Over-the-Air Multi-User Convolutional Code for URLLC |
| title_full | An Over-the-Air Multi-User Convolutional Code for URLLC |
| title_fullStr | An Over-the-Air Multi-User Convolutional Code for URLLC |
| title_full_unstemmed | An Over-the-Air Multi-User Convolutional Code for URLLC |
| title_short | An Over-the-Air Multi-User Convolutional Code for URLLC |
| title_sort | over the air multi user convolutional code for urllc |
| topic | Ultra-reliable low-latency communications channel coding multi-user uplink non-orthogonal multiple access maximum likelihood decoding |
| url | https://ieeexplore.ieee.org/document/11015616/ |
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