Packet Scheduling in Multihop Networks with Individual Packet Delay Constraints

Abstract

We consider a problem of timely scheduling of packets in a multihop wireless network where each packet of each flow is required to reach the destination before a delay deadline. We ask the following question: given an initial energy in each node, what is an optimal timely scheduling strategy that maximizes end-to-end packet transmissions of flows. We consider a time-slotted system. During each time-slot, a packet of a flow arrives according to a certain arrival process. The route of each flow is fixed. The problem is to choose a set of non-interfering links in each time-slot so that packets of various flows reach their destinations before the deadline. The links experience fading, and thus, the problem is also one of choosing links that correspond to minimum total energy for transmission. We provide a scheduling algorithm based on energy expenditure in each time-slot, which we call Minimum Per-packet Energy (MPE) scheduler, and compare the throughput performance of our proposed solution (MPE) with that of a Modified MaxWeight (MMW) and a Modified BackPressure (MBP) solution. The modification made to MaxWeight and BackPressure is to ensure that all three algorithms (MMW, MBP and MPE) are compared on a common set of constraints.