MMSE Filtering Performance of DH-AF Massive MIMO Relay Systems with Residual Transceiver Impairments

The emerging requirements of the fifth generation
(5G) wireless communications are high spectral efficiency, low
latency, and ubiquitous coverage. In this direction, Dual-Hop
(DH) Amplify-and-Forward (AF) relaying has been widely investigated
due to its simplicity, low implementation complexity and
low transmission delay. However, most existing works assume
ideal transceiver hardware which is impractical. In practice, a
cost-efficient wireless transceiver has to combat the effects of
several inevitable impairments such as high power amplifier
nonlinearities, In-phase/Quadrature-phase (I/Q)-imbalance, and
oscillator phase noise, which can be only partially compensated
using calibration algorithms. In this direction, this paper analyzes
the Minimum Mean Square Error (MMSE) filtering performance
of a DH-AF Multiple-Input-Multiple-Output (MIMO) wireless
system considering the effects of the residual additive impairments
at the transmitter and receiver of both hops. Using
free probability principles, the MMSE filtering performance of
the considered system is studied and a tight lower bound is
proposed by taking the effects of residual additive transceiver
impairments into account. Our numerical results show that the
MMSE filtering performance of the DH-AF massive MIMO relay
system significantly degrades and results to saturation in the
presence of residual additive transceiver impairments.