Resource Allocation for IRS-Enabled Secure Multiuser Multi-Carrier Downlink URLLC Systems

Abstract

Secure ultra-reliable low-latency communication (URLLC) has been recently investigated with the fundamental limits of finite block length (FBL) regime in mind. Analysis has revealed that when eavesdroppers outnumber BS antennas or enjoy a more favorable channel condition compared to the legitimate users, base station (BS) transmit power should increase exorbitantly to meet quality of service (QoS) constraints. Channelinduced impairments such as shadowing and/or blockage pose a similar challenge. These practical considerations can drastically limit secure URLLC performance in FBL regime. Deployment of an intelligent reflecting surface (IRS) can endow such systems with much-needed resiliency and robustness to satisfy stringent latency, availability, and reliability requirements. We address this problem and propose a joint design of IRS platform and secure URLLC network. We minimize the total BS transmit power by simultaneously designing the beamformers and artificial noise at the BS and phase-shifts at the IRS, while guaranteeing the required number of securely transmitted bits with the desired packet error probability, information leakage, and maximum affordable delay. The proposed optimization problem is nonconvex and we apply block coordinate descent and successive convex approximation to iteratively solve a series of convex subproblems instead. The proposed algorithm converges to a suboptimal solution in a few iterations and attains substantial power saving and robustness compared to baseline schemes.

Joint Sum Rate and Blocklength Optimization in RIS-Aided Short Packet URLLC Systems

“…The authors showed that the relayassisted networks outperformed direct transmission schemes significantly, though the RIS technology was not the main study topic. Also, [11] studied minimizing the BS transmit power in a RIS-assisted multiple-input-single-output (MISO)-URLLC secure system to design artificial noise, BS beamformer and RIS passive beamforming where the QoS secrecy rate constraint was also taken into account. A CBL allocation, UAV path planning, and transmit power control resource allocation OP was proposed in [12] to facilitate URLLC in UAV-assisted systems utilizing short packets.…”

Joint Sum Rate and Blocklength Optimization in RIS-aided Short Packet URLLC Systems

“…To date, a number of works have analyzed resource allocation in URLLC systems under FBL regime, e.g., in [6]- [9]. A seminal work in [6] studied a multi-objective approach to maximize the total FBL rate while minimizing the largest target error probability by designing transmit power of BS, and the target error probabilities for users in a noise-limited regime.…”

“…The authors showed that the relayassisted networks outperformed direct transmission schemes significantly, though the RIS technology was not the main study topic. Also, [9] studied minimizing the BS transmit power in a RIS-assisted multiple-input-single-output (MISO)-URLLC secure system to design artificial noise, BS beamformer and RIS passive beamforming where the QoS secrecy rate constraint was also taken into account.…”