Enhanced FFR Scenario for Pilot Contamination Mitigation in 5G Systems with Massive Mimo

Abstract

Massive multiple-input multiple-output (MIMO) is the technology of the future, because it has the capability to increase a wireless system capacity without costing the system to purchase an additional bandwidth. It also has the capability to decrease the energy consumption of the system. All these capabilities have promoted the massive MIMO to be a promising technology for the fifth generation (5G) wireless communication systems. However, it has an important issue that limits the benefits which can be acquired by deploying it in 5G. This issue is the pilot contamination, which means the interference between pilot sequences. This occurs when the same pilot sequence is used by more than one terminal in the channel estimation phase at the same time and this causes interference between data symbols later. In this paper, we propose an enhanced fractional frequency reuse (FFR) scenario to mitigate the effects of pilot contamination by following an algorithm in assigning the pilot sequences to the system terminals instead of the random assignment. Simulation results show that our proposed scenario outperforms the traditional FFR in terms of signal to interference and noise ratio (SINR) and capacity