Transmission Power Determination Based on Power Amplifier Operations in Large-Scale MIMO-OFDM Systems

• Published in: Applied sciences Vol. 7; no. 7; p. 709
• Main Authors: Lee, Byung, Kim, Youngok
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 09-07-2017
• Subjects: antenna; Antennas; Closed form solutions; Energy efficiency; Exact solutions; large-scale MIMO; MIMO communication; Optimization techniques; Orthogonal Frequency Division Multiplexing; power amplifier; Power amplifiers; Power consumption; Radiation; Receivers & amplifiers
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app7070709

This paper presents a method to determine transmission power based on power amplifier (PA) operations in order to improve the energy efficiency (EE) of a large-scale (LS) Multiple Input Multiple Output (MIMO)-OFDM system, which is a multi-carrier multiple antenna system with a large amount of transmitter (TX) antennas. Regarding the EE improvement, we propose two kinds of PA operation schemes: increasing the effective TX power (ITXP) and reducing the PA power consumption (RPC) assuming that a reduction of peak-to-average power ratio is applied in the appropriate manner. Closed-form expressions of relative EE are derived for both schemes, and the relative EE of the ITXP scheme is shown to depend on the precoding method that is applied to reduce the inter-user interference, while that of the RPC scheme is independent of the precoding method. The relative EE difference between the ITXP and the RPC schemes is also shown to rely on the occupation ratio of the PA power consumption over the total power consumption. Thus, the EE can remarkably improve by selecting the appropriate scheme based on the circumstances. The results of a simulation also validate the derived closed-form expression of the relative EE.