On the Potentials of Traffic Steering in HetNet Deployments with Carrier Aggregation

This paper investigates the potentials of Traffic Steering (TS) in Carrier Aggregation (CA) deployments. TS is defined as the mechanism to optimally distribute traffic among the deployed cells. Obviously, such functionality is rather crucial in scenarios where solely non-CA User Equipments (UE) are present. The introduction of CA is expected to simplify inter-layer load balancing, as CA UEs can concurrently connect to multiple carriers. In order to evaluate the relevance of TS when CA is enabled, a simple TS framework is developed, where load balancing decisions are applied in both Radio Resource Control (RRC) UE states. System level simulations have been conducted for different deployments and CA UE ratios. The corresponding results show that TS should be mandatory for any CA penetration below 50%, irrespective of the network deployment. Nevertheless, for scenarios where the number of deployed carriers is greater than the multi-carrier connectivity capabilities of the CA device, TS should be applied even for higher CA UE ratios, since the CA scheduler cannot solely resolve the load imbalances.