Performance analysis of two-tier multiantenna 5G heterogeneous wireless networks with dual band transmission

The goal of this paper is to present and analyze the performance of new multiantenna heterogeneous network architectures utilizing both the microwave and millimeter wave frequency bands. Two new architectures are presented viz: microwave macrocell base station with dual band small cell base stations and dual band macrocell base station with mmWave small cell base stations. The effect of dynamically selecting transmission frequency and adjusting coverage regions for each frequency band on the proposed architectures is evaluated via rigorous simulation. We perform simulations to study the performance of Zero Forcing (ZF) based transmit beamforming for interference coordination on the two architecture and compare with classical single band heterogeneous network architecture. Our results show that the proposed dual band architectures offer improved sum rate performance over classical single band networks. The performance gain increases with increasing network densification. We observe that the architecture with dual band small - cell base stations offer better performance when compared with the architecture utilizing dual band air interface at the macro-cell base station. The effect of varying mmWave coverage distance on the performance of the proposed network architectures is also evaluated. Our simulation results shows that decreasing/increasing the inner radius of the small - cells results in significant decrease/increase in both sum rate and per user rate. However, no significant change in rate is observed with similar variation in the macro - cell millimeter wave coverage area.