92 research outputs found
A successive optimization approach to pilot design for multi-cell massive MIMO systems
In this letter, we introduce a novel pilot design approach that minimizes the total mean square errors of the minimum mean square error estimators of all base stations (BSs) subject to the transmit power constraints of individual users in the network, while tackling the pilot contamination in multicell Massive MIMO systems. First, we decompose the original non-convex problem into distributed optimization sub-problems at individual BSs, where each BS can optimize its own pilot signals given the knowledge of pilot signals from the remaining BSs. We then introduce a successive optimization approach to transform each optimization sub-problem into a linear matrix inequality (LMI) form, which is convex and can be solved by available optimization packages. Simulation results confirm the fast convergence of the proposed approach and prevails a benchmark scheme in terms of providing higher accuracy
Integrated Sensing and Communication for Network-Assisted Full-Duplex Cell-Free Distributed Massive MIMO Systems
In this paper, we combine the network-assisted full-duplex (NAFD) technology
and distributed radar sensing to implement integrated sensing and communication
(ISAC). The ISAC system features both uplink and downlink remote radio units
(RRUs) equipped with communication and sensing capabilities. We evaluate the
communication and sensing performance of the system using the sum communication
rates and the Cramer-Rao lower bound (CRLB), respectively. We compare the
performance of the proposed scheme with other ISAC schemes, the result shows
that the proposed scheme can provide more stable sensing and better
communication performance. Furthermore, we propose two power allocation
algorithms to optimize the communication and sensing performance jointly. One
algorithm is based on the deep Q-network (DQN) and the other one is based on
the non-dominated sorting genetic algorithm II (NSGA-II). The proposed
algorithms provide more feasible solutions and achieve better system
performance than the equal power allocation algorithm.Comment: 14 pages, 7 figures,submit to China Communication February 28, 2023,
date of major revision July 09, 202
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