Load-based traffic steering in multi-layer scenarios: Case with & without carrier aggregation

This paper aims at evaluating different mechanisms for providing Inter-Frequency (IF) Load Balancing (LB) in multi-layer heterogeneous deployments. More specifically, the performance of IF mobility management based on signal quality measurements is compared against a load-dependent Traffic Steering (TS) framework that triggers IF mobility events only if load imbalance is detected. To evaluate the joint interaction of the aforementioned schemes with more advanced LB features, system level simulations have been conducted with and without Carrier Aggregation (CA) capable users. Results have shown that although quality-based handoff procedures can act as a passive TS mechanism, they are costly in handovers and measurements gaps. The developed TS scheme utilizes cell neighbor measurements more efficiently, achieving significant handover reduction. Finally, CA makes the proposed framework even more attractive, since its careful parameterization becomes less relevant and load imbalances can be tackled by the packet scheduler as well.