Joint User Selection, Power Allocation, and Precoding Design with Imperfect CSIT for Multi-Cell MU-MIMO Downlink Systems

Jiwook Choi, Namyoon Lee, Song Nam Hong, Giuseppe Caire

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

In this paper, a new optimization framework is presented for the joint design of user selection, power allocation, and precoding in multi-cell multi-user multiple-input multiple-output (MU-MIMO) systems when imperfect channel state information at transmitter (CSIT) is available. By representing the joint optimization variables in a higher-dimensional space, the weighted sum-spectral efficiency maximization is formulated as the maximization of the product of Rayleigh quotients. Although this is still a non-convex problem, a computationally efficient algorithm, referred to as generalized power iteration precoding (GPIP), is proposed. The algorithm converges to a stationary point (local maximum) of the objective function and therefore it guarantees the first-order optimality of the solution. By adjusting the weights in the weighted sum-spectral efficiency, the GPIP yields a joint solution for user selection, power allocation, and downlink precoding. The GPIP can be extended to the multi-cell scenario where cooperative base stations perform joint user-cell selection and design their precodes by taking into account the inter-cell interference by sharing global imperfect CSIT. System-level simulations show the gains of the proposed approach with respect to conventional user selection and linear downlink precoding.

Original languageEnglish
Article number8851389
Pages (from-to)162-176
Number of pages15
JournalIEEE Transactions on Wireless Communications
Volume19
Issue number1
DOIs
StatePublished - 2020 Jan

Keywords

  • Multi-user multiple-input multiple-output (MU-MIMO)
  • precoding
  • user-selection

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