Dynamic Frequency Reuse in Dense Cellular Networks

Network densification has emerged as a powerful paradigm to boost spectral efficiency and accommodate the continual rise in demand for wireless capacity. In dense cell deployments however, overlapping coverage areas may cause highly varying interference conditions among different cells. Moreover, denser networks experience more temporal load fluctuations due to daily and hourly changing usage patterns. The currently applied universal reuse frequency allocation is not suitable to deal with these issues, and needs to be tailored to dense cell deployments to ensure adequate performance in such scenarios. In this paper we present a dynamic, load aware and self-adapting frequency allocation scheme designed for dense cellular networks: the DyCRA scheme (Dynamic Cost/Reward based Allocation). The scheme makes decisions based on cost-reward trade-offs: rewards arise in the form of capacity, and costs arise in the form of interference (under spatial reuse). We quantify these costs and rewards based on SINR, and use periodic load estimates to determine if access points are in need of extra frequencies, or can spare them, and the cost/reward structure is used to determine which frequencies are allocated or released. Extensive simulation results show that the DyCRA scheme provides efficient resource allocations that adapt to changing traffic conditions and yields significant performance gains in scenarios with nonstationary traffic demands.