Energy-Efficient Non-Orthogonal Transmission under Reliability and Finite Blocklength Constraints

TL;DR

This paper proposes an energy-efficient non-orthogonal transmission scheme for two receivers with strict reliability and finite blocklength constraints, optimizing power and code length under realistic finite blocklength capacity models.

Contribution

It introduces a novel optimization framework for non-orthogonal transmission considering finite blocklength effects and heterogeneous channel conditions, with closed-form solutions for power and code length.

Findings

Non-orthogonal transmission can be more energy-efficient than TDMA under certain conditions.

Finite blocklength capacity models are essential for accurate reliability and latency trade-offs.

Optimal power and code length are derived explicitly for various channel scenarios.

Abstract

This paper investigates an energy-efficient non-orthogonal transmission design problem for two downlink receivers that have strict reliability and finite blocklength (latency) constraints. The Shannon capacity formula widely used in traditional designs needs the assumption of infinite blocklength and thus is no longer appropriate. We adopt the newly finite blocklength coding capacity formula for explicitly specifying the trade-off between reliability and code blocklength. However, conventional successive interference cancellation (SIC) may become infeasible due to heterogeneous blocklengths. We thus consider several scenarios with different channel conditions and with/without SIC. By carefully examining the problem structure, we present in closed-form the optimal power and code blocklength for energy-efficient transmissions. Simulation results provide interesting insights into conditions for which non-orthogonal transmission is more energy efficient than the orthogonal transmission such as TDMA.