Energy Efficiency Analysis for Wideband MIMO Transmission in Finite Blocklength Regime

It is supposed that ultra-reliable low-latency communication (uRLLC) will continue to evolve in the future sixth-generation (6 G) network, and finite blocklength will play an important role in its theoretical analysis. In this paper, an energy efficiency (EE) model related to finite blocklength is considered in a wideband massive MIMO system. Based on the model, we first derive an close-form expression for the upper bound value of the optimal signal-to-noise ratio (SNR) corresponding to the maximum EE as a function of the blocklength and the error probability. With this value, we demonstrate that finite blocklength also leads to reduced EE performance. Since the finite blocklength can represent the latency constraint in the time domain, we further show that it can be reduced by incorporating parameters from both the frequency and spatial domains, which are equivalent to one another. Furthermore, by accounting circuit power consumption in the system, we incorporated it into the EE model and derive new boundary values to assess its impact on EE in the finite blocklength regime. Finally, through simulation and analysis, we validate the equivalence of frequency and spatial domain parameters and comparing their respective effects on EE.