QS-PS: A new approach for emergency packet delivery in WBAN

Abstract

Energy efficiency, reliability and latency for packet delivery are three key issues in WBAN. Energy efficiency and reliability can be guaranteed in a tree-basedWBAN.However, there exists an inertial problem: when an emergency packet occurs in one node, that node has to wait for its assigned slot to transmit such a life-critical packet, resulting in unbearable delay. Here, we propose a new scheme named Quasi-Sleep-Preemption-Supported (QS-PS) to tackle with that problem. First, those nodes whose dedicated slots have elapsed will enter a new Quasi-Sleep mode. When an emergency event occurs, emergency node will first broadcast a special designed Awakening Message at the beginning of next slot to wake up the whole network. Then, the slot preemption strategy allows the emergency node to preempt the right to use the slot. This process will continue until the emergency packet arrivals at the root, thus reducing delay. Compared to two basic threshold methods, Full-Active-Preemption-Supported (FA-PS, delay guaranteed) and Strict-Sleep-Preemption-Unsupported (SS-PU, energy efficiency guaranteed), the newly proposed QS-PS scheme can achieve the similar latency as FA-PS while reducing energy consumption of the whole network by 57%, and holds tremendous latency improvement over SS-PU just at a small energy cost.