Pilot contamination mitigation under smart pilot allocation strategies within massive MIMO-5G system

Abstract

Within massive multiple-input-multiple-output (Massive MIMO) system, pilot contamination (PC) is deemed as a stumbling block in boosting the spectral efficiency (SE) regarding fifth-generation (5G) wireless communication network. To alleviate efficacy of PC, efficient sectorization-based pilot allocation (ES-PA) scheme is recommended, here users equipment (UE) are divided corresponding to their signal-to-interference-plus-noise-ratio (SINR) within two zones, i.e., cell center zone and edge zone. Smart antenna technique is used to split up edge zone further into N uniform sectors. The UE present in the cell center zone are allotted with identical pilot sequences on account of lower inter-cell-interference (ICI), whereas UE present in each sector of edge zone is allotted with mutually orthogonal pilot sequences to diminished PC. The simulation results illustrates that this recommended approach substantially attenuate strength of PC, avail lower mean squared error (MSE), greater data rate and superior SE as compared to conventional pilot allocation methods. In another effective proposed scheme II for mitigating PC, all active users are initially classified between high interference UH and low interference UL users premised on their large scale-fading. An efficient pilot allocation approach in accordance with edge weighted interference graph (EWIG) is recommended to clarify low interference users UL. Simulation output reveals that recommended scheme II upgrade both uplink achievable rate (R) and SINR. Additionally, the recommended approach is considerably competent of mitigating PC and maximizing system performance.