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arXiv · 1805.01332

Energy-Latency Tradeoff in Ultra-Reliable Low-Latency Communication with Retransmissions

Apostolos Avranas·Marios Kountouris·Philippe Ciblat
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Abstract

High-fidelity, real-time interactive applications are envisioned with the emergence of the Internet of Things (IoT) and tactile Internet by means of ultra-reliable low-latency communications (URLLC). Exploiting time diversity for fulfilling the URLLC requirements in an energy efficient manner is a challenging task due to the nontrivial interplay among packet size, retransmission rounds and delay, and transmit power. In this paper, we study the fundamental energy-latency tradeoff in URLLC systems employing incremental redundancy (IR) hybrid automatic repeat request (HARQ). We cast the average energy minimization problem with a finite blocklength (latency) constraint and feedback delay, which is non-convex. We propose a dynamic programming algorithm for energy efficient IR-HARQ optimization in terms of number of retransmissions, blocklength and power per round. Numerical results show that our IR-HARQ approach could provide around 25\% energy saving compared to one-shot transmission (no HARQ).

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Apostolos Avranas, Marios Kountouris, Philippe Ciblat. 2018-05-03. Energy-Latency Tradeoff in Ultra-Reliable Low-Latency Communication with Retransmissions. https://arxiv.org/abs/1805.01332

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