On the Effective Energy Efficiency of Ultra-reliable Networks in the Finite Blocklength Regime

TL;DR

This paper investigates the energy efficiency of ultra-reliable networks in the finite blocklength regime, providing a closed-form approximation and optimal power strategies to enhance performance under delay and buffer constraints.

Contribution

It introduces a closed-form approximation for EEE in finite blocklength Rayleigh channels and identifies optimal power allocation strategies, highlighting differences from Shannon's model.

Findings

Optimal power allocation improves EEE in finite blocklength regimes.

Accounting for buffer constraints and delay tolerance enhances EEE.

Finite blocklength models outperform Shannon's model in power estimation.

Abstract

Effective Capacity (EC) indicates the maximum communication rate subject to a certain delay constraint while effective energy efficiency (EEE) denotes the ratio between EC and power consumption. In this paper, we analyze the EEE of ultra-reliable networks operating in the finite blocklength regime. We obtain a closed form approximation for the EEE in Rayleigh block fading channels as a function of power, error probability, and delay. We show the optimum power allocation strategy for maximizing the EEE in finite blocklength transmission which reveals that Shannon's model underestimates the optimum power when compared to the exact finite blocklength model. Furthermore, we characterize the buffer constrained EEE maximization problem for different power consumption models. The results show that accounting for empty buffer probability (EBP) and extending the maximum delay tolerance jointly enhance the EC and EEE.