Massive MIMO: challenges to acquire CSIT with very large antenna arrays

Abstract

In a wireless communication system, multiple number of antennas are used on transmitting and receiving side in MIMO technology. Now a days, MIMO technology faces some issues. Like the increased complexity of MIMO at the receiver due to point to point links and the complexity at the transmitter for MU MIMO due to advanced coding schemes. The physical space which is required for the antennas is another challenge. But with very large MIMO system called as, Massive MIMO, these issues can be resolved by creating a system in which the transmitter and receiver has larger number of antennas. In Massive MIMO technology, the transmitter and receiver has greater number of antennas resulting in more signal paths and hence better performance is achieved. The traditional time and frequency division multiplexing techniques and OFDM can be employed to go towards Massive MIMO technology. Massive MIMO technology is an important research area in communication as well as in electronics. But with an unlimited number of terminals, it is difficult to investigate channel state information at the transmitter. Therefore, a scheme is proposed that how we can achieve CSIT (Channel State Information At Transmitter), when the antennas grow to infinity and the challenges for acquiring CSIT are also addressed. The phenomenon of Pilot Contamination is also a little concern and it is undetermined when Pilot Contamination will constitute an ultimate limit on performance.