Transmit non linearity and its effects on the performance of massive MIMO systems with non-ideal hardware

Abstract

The requirement of higher data throughput in wireless communication systems is ever increasing. The 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. The data throughput requirement will even surpass this new technology very shortly. Discussions regarding 5G has already started. Massive MIMO is able to cope with the increased bandwidth requirements. Research is still underway to get maximum benefits from this new technology. Out of the many important parameters to optimize data throughput in Massive MIMO systems is the effect of Non-Ideal Hardware on signal propagation. Non-Ideal Hardware cause impairments in the wireless transceivers. 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 most pronounced at the User Equipment (UE), while the impact of hardware impairments vanishes asymptotically in large scale arrays. The huge degrees of freedom offered by Massive MIMO can be used to reduce the transmit power and to tolerate larger hardware impairments, which allows for the use of energy efficient and inexpensive antenna elements. In this study different Models of the Main RF Impairments have been studied. 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.