Optimal Pilot and Payload Power Control in Single-Cell Massive MIMO Systems

Fuente: arXiv
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Main Authors: Cheng, Hei Victor, Björnson, Emil, Larsson, Erik G.
Format: Preprint
Published: 2016
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author Cheng, Hei Victor
Björnson, Emil
Larsson, Erik G.
author_facet Cheng, Hei Victor
Björnson, Emil
Larsson, Erik G.
contents This paper considers the jointly optimal pilot and data power allocation in single-cell uplink massive multiple-input-multiple-output (MIMO) systems. Using the spectral efficiency (SE) as performance metric and setting a total energy budget per coherence interval, the power control is formulated as optimization problems for two different objective functions: the weighted minimum SE among the users and the weighted sum SE. A closed form solution for the optimal length of the pilot sequence is derived. The optimal power control policy for the former problem is found by solving a simple equation with a single variable. Utilizing the special structure arising from imperfect channel estimation, a convex reformulation is found to solve the latter problem to global optimality in polynomial time. The gain of the optimal joint power control is theoretically justified, and is proved to be large in the low SNR regime. Simulation results also show the advantage of optimizing the power control over both pilot and data power, as compared to the cases of using full power and of only optimizing the data powers as done in previous work.
format Preprint
id arxiv_https___arxiv_org_abs_1612_02574
institution arXiv
publishDate 2016
record_format arxiv
spellingShingle Optimal Pilot and Payload Power Control in Single-Cell Massive MIMO Systems
Cheng, Hei Victor
Björnson, Emil
Larsson, Erik G.
Information Theory
Signal Processing
Optimization and Control
This paper considers the jointly optimal pilot and data power allocation in single-cell uplink massive multiple-input-multiple-output (MIMO) systems. Using the spectral efficiency (SE) as performance metric and setting a total energy budget per coherence interval, the power control is formulated as optimization problems for two different objective functions: the weighted minimum SE among the users and the weighted sum SE. A closed form solution for the optimal length of the pilot sequence is derived. The optimal power control policy for the former problem is found by solving a simple equation with a single variable. Utilizing the special structure arising from imperfect channel estimation, a convex reformulation is found to solve the latter problem to global optimality in polynomial time. The gain of the optimal joint power control is theoretically justified, and is proved to be large in the low SNR regime. Simulation results also show the advantage of optimizing the power control over both pilot and data power, as compared to the cases of using full power and of only optimizing the data powers as done in previous work.
title Optimal Pilot and Payload Power Control in Single-Cell Massive MIMO Systems
topic Information Theory
Signal Processing
Optimization and Control
url https://arxiv.org/abs/1612.02574