Independent Encoding Versus Joint Encoding: Short Frame Structure Optimization for Heterogeneous URLLC Systems

Independent Encoding Versus Joint Encoding: Short Frame Structure Optimization for Heterogeneous URLLC Systems

IEEE Transactions on Communications

10.1109/TCOMM.2023.3348131

https://doi.org/10.1109/tcomm.2023.3348131

Xiayue Liu, Xu Zhu, Yufei Jiang, Jie Cao, Sumei Sun, Vincent K. N. Lau

Ultra reliable and low latency communication , joint encoding , joint optimization , pilot power boosting , heterogeneous traffic

29 December 2023

Liu, X., Zhu, X., Jiang, Y., Cao, J., Sun, S., & Lau, V. K. N. (2024). Independent Encoding Versus Joint Encoding: Short Frame Structure Optimization for Heterogeneous URLLC Systems. IEEE Transactions on Communications, 72(6), 3463–3480. https://doi.org/10.1109/tcomm.2023.3348131

Short frame structure and its optimization plays an important role in ultra reliable and low latency communication (URLLC). We investigate and compare the latency and throughput performances of the independent encoding (IE) and joint encoding (JE) frame structures for heterogeneous multi-device URLLC in the finite block length regime. There is a counter-intuitive finding that, despite a longer frame, IE enables a much lower average latency and higher reliability than JE, thanks to lower queuing latency, while JE achieves higher throughput with lower traffic heterogeneity, thanks to less channel dispersion. It is also shown that traffic heterogeneity has less adverse effects on the performance of the IE frame structure, and can even help reduce its average latency with the shortest block length first (SBF) scheduling rule proposed. We also provide an intensive analysis of the trade-off between pilot power and pilot overhead, with near-optimal pilot power and block length derived in closed form. Low-complexity joint pilot power, pilot length and block length optimization algorithms are proposed for IE and JE frame structures. Numerical results verify the effectiveness of the proposed algorithms, and also show that pilot power optimization plays a significant role in enhancing throughput at low to medium SNR.

Publisher Copyright

This research is supported by core funding from: A*STAR Institute for Infocomm Research (A*STAR I²R)
Grant Reference no. :

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