On the Mobility of Moderate Speed Users in Ultra Dense Small Cell Deployments with mmW

This paper deals with mobility robustness in a context of ultra-dense deployments operating at the millimeter wave (mmW) band. In order to increase the threshold speed of user equipments (UEs) allowed at the small cell layer, we propose the use of selective Control/User-plane split combined with a non-coherent cooperative multi- point (CoMP) joint transmission (JT). This way, users at moderate speeds can also benefit from the new cell layer and improve their performance with respect to a pure macrocellular operation. The combination of this strategy with a fine tuning of the measurement gap interval allows reducing handover failure rates, which eventually translates into a throughput improvement. On the other hand, increasing the number of measurements leads to a higher UE power consumption, fact that has also been quantified and evaluated.