Title
Achieving Energy-Efficient Uplink URLLC With MIMO-Aided Grant-Free Access
Abstract
The optimal design of the energy-efficient multiple-input multiple-output (MIMO) aided uplink ultra-reliable low-latency communications (URLLC) system is an important but unsolved problem. For such a system, we propose a novel absorbing-Markov-chain-based analysis framework to shed light on the puzzling relationship between the delay and reliability, as well as to quantify the system energy efficiency. We derive the transition probabilities of the absorbing Markov chain considering the Rayleigh fading, the channel estimation error, the zero-forcing multi-user-detection (ZF-MUD), the grant-free access, the ACK-enabled retransmissions within the delay bound and the interactions among these technical ingredients. Then, the delay-constrained reliability and the system energy efficiency are derived based on the absorbing Markov chain formulated. Finally, we study the optimal number of user equipments (UEs) and the optimal number of receiving antennas that maximize the system energy efficiency, while satisfying the reliability and latency requirements of URLLC simultaneously. Simulation results demonstrate the accuracy of our theoretical analysis and the effectiveness of massive MIMO in supporting large-scale URLLC systems.
Year
DOI
Venue
2022
10.1109/TWC.2021.3104043
IEEE Transactions on Wireless Communications
Keywords
DocType
Volume
Ultra-reliable low-latency communications (URLLC),grant-free access,massive MIMO,energy efficiency,absorbing Markov chain
Journal
21
Issue
ISSN
Citations 
2
1536-1276
1
PageRank 
References 
Authors
0.39
0
5
Name
Order
Citations
PageRank
Linlin Zhao171.82
Shaoshi Yang240423.55
Xuefen Chi384.87
Wanzhong Chen431.09
Shaodan Ma566671.25