Scheduling in Multi-Hop Wireless Networks With Deadlines

Abstract

We analyze the problem of scheduling in wireless networks to meet end-to-end service guarantees, defined by instantaneous throughput and hard packet deadlines. Using a network slicing model to decouple the queueing dynamics between flows, we show that the network's ability to meet hard deadline guarantees under interference is largely influenced by the link scheduling policy. We characterize throughput- and deadline-optimal policies for a solitary flow operating in isolation, which provide bounds on feasibility in the general case with multiple flows. We prove that packet delays can grow arbitrarily large in the multi-flow setting under a worst-case stabilizing policy, showing that queue stability is not sufficient to guarantee tight deadlines. We derive conditions on end-to-end packet delays in terms of link inter-scheduling times, and show that it is possible to make hard guarantees under any interference model by solving a generalized version of the pinwheel scheduling problem. Finally, we introduce a decentralized polynomial-time algorithm which can meet tight end-to-end packet deadlines while achieving near-optimal throughput.