Achievable Rate Region for uRLLC Interference Channel With Finite Blocklength Transmission

Abstract

Finite blocklength is a favorable way to meet the extremely low-latency requirement, which leads to the classic Shannon's capacity formula no longer suitable. With the achievable rate region, optimization problems on three different scenarios are considered: (i) joint design of power and blocklength allocation for two transceiver pairs with single-antenna transmitter; (ii) beamforming and blocklength design for the two transceiver pairs with multi-antenna transmitter; (iii) beamforming and blocklength design for the multiple transceiver pairs with multi-antenna transmitter. Under the finite blocklength transmission mode, the achievable rate expression is a complicated function with respected to the blocklength and power allocation coefficients or beamforming vector, which makes the optimization problems difficult to solve. In this paper, by analyzing the monotonic and concaveconvex properties of achievable rate with interference channel (IFC), we formulate the achievable rate region as the convex hull of a series of power/beamforming and blocklength rate regions for two-user systems with IFC, as well as the Pareto boundary of achievable rate region on the blocklength and beamforming vector for the two-user systems, respectively. Sequentially, the optimal blocklength and power coefficients are derived in the closed-form and optimal beamforming vectors are also obtained by transforming the non-convex problem into convex one. Numerical results provide the perspective of looking at the rate region with finite blocklength.