System Model for Average Downlink SINR in 5G Multi-Beam Networks

To study critical 5G mobility features like zero-millisecond interruption time and multi-connectivity, an average downlink Signal-to-Interference and Noise Ratio (SINR) is needed for radio link failure detection and throughput calculation. This paper presents an accurate approximation of the average downlink SINR with low computational complexity in 5G networks where the base station forms multiple beams simultaneously. To this end, geometry-based link budget is formulated first for both desired and interfering downlink signals. Then, a closed form expression of the average downlink SINR is derived for multi-beam scheduling system and approximated by Monte-Carlo experiment using beam scheduling probabilities. In addition, the SINR model is derived for both strict and opportunistic resource fair scheduler where the latter targets a higher utilization of radio resources. Results have revealed that with increasing number of scheduled beams, the average downlink SINR generally degrades while the network throughput improves. Moreover, it has been also shown that the opportunistic resource fair scheduler performs better than the strict in terms of utilizing available network resources.