Dimensioning of PA for massive MIMO system with load adaptive number of antennas

TL;DR

This study investigates how realistic power amplifier characteristics and daily traffic patterns influence the energy efficiency of load adaptive massive MIMO systems, optimizing antenna and PA dimensions over 24 hours.

Contribution

It introduces a method to dimension PAs and antennas considering load variability and PA efficiency, improving energy efficiency in massive MIMO systems.

Findings

Achieves 30% higher energy efficiency with load adaptive design.

Optimizes PA and antenna dimensions for daily traffic profiles.

Demonstrates benefits over fixed-antenna systems.

Abstract

This paper takes into consideration the non-ideal efficiency characteristics of realistic power amplifiers (PAs) along with the daily traffic profile in order to investigate the impact of PA dimensioning on the energy efficiency (EE) of load adaptive massive MIMO system. A multicellular system has been considered where each base station (BS) is equipped with a large number of antennas to serve many single antenna users. For a given number of users in a cell, the optimum number of active antennas maximizing EE has been derived where total BS downlink power is assumed to be fixed. Under the same assumption, the PAs have been dimensioned in a way that maximizes network EE not only for a single time snapshot but over twenty four hours of operation while considering dynamic efficiency characteristics of the PAs. In order to incorporate this daily load profile, each BS has been modeled as an M/G/m/m state dependent queue under the assumption that the network is dimensioned to serve a maximum number of users at a time corresponding to 100% cell traffic load. This load adaptive system along with the optimized PA dimensioning achieves 30% higher energy efficiency compared to a base line system where the BSs always run with a fixed number of active antennas which are most energy efficient while serving 100% traffic load.