Tackling Mobility in Low Latency Deterministic Multihop IEEE 802.15.4e Sensor Network

Providing reliable services for low latency (LL) applications within the IoT context is a challenging issue. Several wireless sensor network (WSN) applications require deterministic systems that ensure a reliable and low latency aggregation service. The IEEE 802.15.4e standard, which is considered as the backbone of the IoT regarding WSN, has presented the low-latency deterministic network mode (LLDN) that can fulfil the major requirements of low latency applications. Meanwhile, several LL applications, for example in the automotive industry, demand the support of sensor node mobility which in turn affects network performance. Node mobility triggers several dissociations from the network that will increase latency and degrade node throughput. In this paper, we investigate the impact of node mobility over the LLDN mode while defining key factors that maximize latency and degrade throughput. In addition, an enhanced version of the LLDN mode is presented and evaluated that supports node mobility while maintaining the targeted limits of LL application requirements. The proposed mobility aware (MA-LLDN) technique manages to reduce the dissociation overhead by a factor of 75% while the packet delivery ratio (PDR) has been enhanced by 30%. Furthermore, this paper presents an analytical model that provides a snapshot of the tradeoff process between different metrics in the IEEE 802.15.4e LLDN design, which must be considered prior network deployment in mobile LL applications.