An Innovative Pilot Assignment Technique for Pilot Contamination Suppression in TDD Massive MIMO

Abstract

Time division duplex (TDD) massive multiple-input multiple-output (massive MIMO) has been regarded as a fantabulous technology for fifth generation wireless cellular networks (5G) to improve spectral efficiency (SE) and network performance using tens of hundreds of antennas and terminals attached to the base station (BS). On the other hand, the concept of pilot contamination (PC) is believed to be an acquainted gainsay in massive MIMO caused by channel estimation error, which disrupts and demarcates these required objectives. This paper projects an innovative strategy for pilot allocation i.e. cell splitting and sectorization based pilot assignment (CSS-PA) strategy to mitigate the PC. This strategy is based on exploiting signal to interference plus noise ratio (SINR), the users are first categorized into cell center and edge zones, followed by the subsequent sectorization of edge zones of each cell. Then, each cell center zone users are allotted with identical pilot sequences. On contrast, for edge zone sectors, the appointed sequences are mutually orthogonal in different cells. With the assistance of mitigated PC, we have ascertained the approximate system capacity, which shows precision for the unlimited number of antennas at the BS. The outcome of simulation reveals that our proposed CSS-PA strategy would effectively weaken PC. Moreover, the proposed idea has achieved higher system throughput, low Mean Square Error (MSE) and Normalized MSE (NMSE) at higher signal to noise ratio (SNR) and maximum number of BS antennas in comparison to the traditional pilot sequences allocation strategy with the marked sequences reuse rate of one or three.