Open AccessPilot power allocation for maximising the sum rate in massive MIMO systems
Author(s) -
Dao Hieu Trong,
Kim Sunghwan
Publication year - 2018
Publication title -
iet communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.355
H-Index - 62
eISSN - 1751-8636
pISSN - 1751-8628
DOI - 10.1049/iet-com.2017.1407
Subject(s) - mathematical optimization , telecommunications link , computer science , lagrange multiplier , mimo , convex optimization , optimization problem , fading , power (physics) , mathematics , regular polygon , algorithm , telecommunications , beamforming , decoding methods , physics , quantum mechanics , geometry
In this study, the authors investigate the issue of pilot power allocation in multi‐cell multi‐user massive multiple‐inputmultiple‐output (MIMO) systems to maximize the sum rate. In contrast to conventional scheme that assigns equal pilot power for all users in the system, they assume that different users can be assigned different pilot powers while the total pilot power per cell is fixed. They show that when the number of BS antennas goes to infinity, the signal‐to‐interference‐and‐noise ratio of a user only depends on the large‐scale fading and pilot power of users who have the same pilot sequence. From that they derive an optimization problem to maximize the total uplink achievable rate of a target cell and prove that this problem is convex, which can be solved by the well‐known Lagrange multiplier method. They also propose an extended optimization problem that solves the issue of zero‐pilot power in the original problem. Eventually, two algorithms corresponding to the original and extended optimization problems are proposed to obtain the optimized pilot power set for all users in the systems. Numerical results show that the proposed algorithms outperform the existing methods relating to pilot power allocation problem as well as conventional scheme.