Power Allocation for FDMA-URLLC Downlink with Random Channel Assignment

TL;DR

This paper introduces a lightweight power allocation method for FDMA-URLLC downlink that maximizes user capacity under reliability and power constraints, effective with both perfect and imperfect CSIT.

Contribution

It proposes a novel power allocation approach that enhances URLLC user capacity in downlink FDMA systems with random channel assignment, considering imperfect channel information.

Findings

Significantly improves user capacity in Rayleigh fading channels.

Ensures reliable communication with limited power when CSIT is imperfect.

Enhances power efficiency while maximizing URLLC users.

Abstract

Concerning ultra-reliable low-latency communication (URLLC) for the downlink operating in the frequency-division multiple-access with random channel assignment, a lightweight power allocation approach is proposed to maximize the number of URLLC users subject to transmit-power and individual user-reliability constraints. Provided perfect channel-state-information at the transmitter (CSIT), the proposed approach is proven to ensure maximized URLLC users. Assuming imperfect CSIT, the proposed approach still aims to maximize the URLLC users without compromising the individual user reliability by using a pessimistic evaluation of the channel gain. It is demonstrated, through numerical results, that the proposed approach can significantly improve the user capacity and the transmit-power efficiency in Rayleigh fading channels. With imperfect CSIT, the proposed approach can still provide remarkable user capacity at limited cost of transmit-power efficiency.