Zero-Zero Mobility: Intra-Frequency Handovers with Zero Interruption and Zero Failures

Today's intra-frequency hard handovers in LTE suffer from interruption even if they are successful as well as risk of failures. The next generation, New Radio, will introduce stricter requirements that cannot be fulfilled with the traditional hard handover concept. Namely, a handover with 0 ms interruption is mandated, and extreme reliability (ultra-reliable low-latency communication services) will not tolerate any mobility failures. Consequently, softer handover concepts where the UE is multi-connected to a source and one or more target cells are already under discussion. This article investigates such a method using the well-known dual connectivity principle and evaluates the performance in terms of robustness/ reliability and signaling costs.