Load balancing potential of dynamic fractional frequency reuse

Maximizing the system throughput and bandwidth utilization while guaranteeing fairness is a core scientific and technical challenge for cellular systems. Under orthogonal frequency division multiple access, the fractional frequency reuse scheme provides flexible resources allocation and can be used to jointly optimize power allocation and scheduling of users served at base stations. Solutions developed so far are inefficient in scenarios where the number of users per cell has high variability: users in denser network regions may be penalized. In this work, we introduce a load balancing scheme able to increase the user data rates in the dense parts of heterogeneous networks operating fairness balancing across sectors with different load levels. Our approach is to perform a virtual joint power allocation and scheduling such in a way to determine the sector that can maximize the achievable throughput that a user can be served with by any sector. This information can used to trigger reassociation of users; furthermore this load balancing operation can be run in parallel to normal system operations. We demonstrate through simulations that such a scheme is able to provide a better load balance with respect to existing schemes, without incurring in penalties in terms of the aggregated throughput.