Performance Limits of MIMO Systems with Nonlinear Power Amplifiers

Milad Fozooni, Michail Matthaiou, Emil Björnson, Trung Q. Duong

Research output: Contribution to conferencePaperpeer-review

12 Citations (Scopus)
1419 Downloads (Pure)


The development of 5G enabling technologies brings new challenges to the design of power amplifiers (PAs). In particular, there is a strong demand for low-cost, nonlinear PAs which, however, introduce nonlinear distortions. On the other hand, contemporary expensive PAs show great power efficiency in their nonlinear region. Inspired by this trade-off between nonlinearity distortions and efficiency, finding an optimal operating point is highly desirable. Hence, it is first necessary to fully understand how and how much the performance of multiple-input multiple-output (MIMO) systems deteriorates with PA nonlinearities. In this paper, we first reduce the ergodic achievable rate (EAR) optimization from a power allocation to a power control problem with only one optimization variable, i.e. total input power. Then, we develop a closed-form expression for the EAR, where this variable is fixed. Since this expression is intractable for further analysis, two simple lower bounds and one upper bound are proposed. These bounds enable us to find the best input power and approach the channel capacity. Finally, our simulation results evaluate the EAR of MIMO channels in the presence of nonlinearities. An important observation is that the MIMO performance can be significantly degraded if we utilize the whole power budget.
Original languageEnglish
Number of pages7
Publication statusPublished - 07 Dec 2015
EventIEEE Global Communications Conference 2015 - California, San Diego, United States
Duration: 06 Dec 201510 Dec 2015


ConferenceIEEE Global Communications Conference 2015
Abbreviated titleGLOBECOM 2015
Country/TerritoryUnited States
CitySan Diego
Internet address


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