Optimal Node Density for Multi-RAT Coexistence in Unlicensed Spectrum

Network densification provides coverage by reducing load factor and path loss between user equipments (UEs) and the serving base stations (BSs) or access points (APs) [1]. To increase capacity, a wide range of spectrum in diverse bands could be harnessed by deploying dense multiple radio access technologies (RATs). This benefit of densification is contingent on the interference level generated by high density coexisting nodes and multi-RATs in the same spectrum. To this effect, we seek to optimize the maximum node density that should coexist in a network to maximize throughput performance for high density networks. This is important because increasing network density (densification) increases interference and contention, and subsequently degrades aggregate performance. Using stochastic geometry tools, a special case of two co-existing RATs is considered. Due to the unplanned nature of APs and/or BSs deployments, the nodes are assumed to be realizations of Poisson point processes (PPPs). Numerical results reveal that optimizing node density results in throughput gains for mid to high density networks.