Optimizing Design Parameters for Relay-Aided Massive MIMO Systems

Utilization of relay stations (RSs) in massive multiple input multiple output (MIMO) systems is a challenging task. This paper proposes a relay-aided massive MIMO system under realistic circuit power consumption. The main focus is to search the optimal design parameters (i.e., number of RSs
N
, the number of RS antennas
R
, the number of BS antennas
M
, the number of user equipments
K
, the transmit power at base station (BS)
$\ {p_{{\rm{BS}}}}$
, and the transmit power at RS
${p_{{\rm{RS}}}}$
for maximum energy efficiency (EE). The channel estimation and an arbitrary path loss with perfect and imperfect channel state information are considered. EE optimization problem is formulated with the objective of finding optimal design parameters. This paper also solves an optimization problem using three optimization algorithms, which are standard alternating algorithm, the Charnes–Cooper transform method-based scheme and the Dinkelbach's method-based scheme. Results are used to demonstrate the impacts of various system parameters on the EE performance.