Cell sectorization-based pilot assignment scheme in massive MIMO systems

Pilot contamination has become a major capacity bottleneck in massive MIMO systems. To mitigate pilot contamination, a novel cell sectorization-based pilot assignment (CS-PA) scheme is proposed in this paper. By separating the users that transmit the same pilot in physical space, the pilot transmitted by the user in each sector is orthogonal with pilots transmitted by the users in adjacent sectors. Due to the advantages of cell sectorization and pilot assignment, the proposed CS-PA scheme can effectively suppress pilot contamination. In addition, the proposed CS-PA scheme achieves higher system throughput as the number of base station antennas tends to infinity. The closed-form expression for the achieved rates is derived to verify the advantages of the proposed scheme. Numerical results show that the proposed CS-PA scheme significantly outperforms the typical pilot contamination mitigation methods.