Resource Management in Hybrid Millimeter-Wave and Microwave Ultra-Dense Networks using TDD Duplexing

Millimeter wave (mW) communication is one of the key enabling technologies for meeting the vast data demand growth and bandwith scarcity. The mmWave band offers higher bandwidth compare with those presently used in commercial wireless systems, which resuls in higher achievable capacity. To improve the user experience in the 5G communication, it is proposed to utilize the composition of microwave (μW) and millimeter wave networks. On the other hand, an ultra-dense network (UDN) has been envisioned as a promising network paradigm for spectrum efficiency enhancement. In this paper, the cellular network using TDD duplexing, consists of both mW and μW base stations. BSs and users are distributed in both indoor and outdoor environments with Poisson point distribution. Our aim is to calculate the spectral efficiency for both mW and μW sysyems, based on the base stations and users distribution. Moreover, the effect of BS density on spectral efficiency is evaluated. Finally, the problem of maximizing the downlink rate is formulated and solved as a linear optimization problem so that the minimum uplink rate is guaranted. The simulation results show that by servicing both mW and μW simultaneously on uplink and downlink, high spectral efficiency can be achieved and with the help of optimal resources allocation, the network’s perfomance is improved about 3dB.