Effects of transmit non-linearity on performance of massive MIMO systems

Abstract

The requirement of higher data throughput in wireless communication systems is ever increasing. Exponential growth in mobile data traffic has led researchers to innovative ideas to cater for these new requirements. At present 4th generation wireless systems are being deployed. In near future, data throughput requirements will even surpass this new technology. Research on 5G has already started where, in addition to other technologies Massive MIMO is considered as a strong candidate to cope with the increased bandwidth requirements. Out of the many important parameters which need to be optimized in Massive MIMO systems, non-linear amplification is an important one. This nonlinearity causes impairments in the transmitted signal. Due to these transceiver impairments, restrictions are imposed on the channel estimation accuracy and the capacity of each user in a Massive MIMO scenario. The effect of hardware impairments is more at the User Equipment (UE), however, in large scale arrays the impact of hardware impairments reduces significantly. Transmit power can be reduced and large hardware impairments can be tolerated by capitalizing on the great degree of freedom offered by Massive MIMO. This allows for the use of energy efficient and inexpensive antenna elements. In this study a signal model that incorporates hardware impairments has been derived based on the RAPP Model of non-linear power amplifiers to analyze effects of hardware impairments on signal propagation in LTE systems.