38 research outputs found
Achieving Energy-Efficient Uplink URLLC with MIMO-Aided Grant-Free Access
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.Comment: 14 pages, 9 figures, accepted to appear on IEEE Transactions on
Wireless Communications, Aug. 202
Mobile Ad Hoc Networks
Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms