Average downlink SINR model for 5G mmWave networks with analog beamforming

Millimeter-wave frequency bands enable the deployment of small-sized antenna arrays in the fifth generation of mobile networks, which provide high beamforming gain for both transmitter and receiver. In order to study user mobility, a computationally efficient simulator is needed that runs with a time step resolution that is higher than transmission-time-interval of cellular networks. In such simulators, typically the average downlink signal-to-interference-and-noise ratio (SINR) is used for radio link failure detection and throughput calculation. In this paper, models of desired and interfering signals are formulated first, by considering the impact of antenna beamforming at transmitter and receiver. Then, a closed-form expression of average downlink SINR is derived by taking into account the scheduling probabilities of the users. In addition, the closed form expression is approximated by Monte Carlo method. Simulations are performed to analyze the complexity and accuracy of Monte Carlo method along with the impact of user location and beamforming gain on average downlink SINR. Results confirm that the average downlink SINR is approximated accurately, and the computational complexity of the proposed method is tolerable. In addition, the results reveal that user location and beamforming have significant impact on the average downlink SINR.