Scheduling in Multi-Hop Wireless Networks With Deadlines

TL;DR

This paper investigates scheduling strategies in multi-hop wireless networks to meet strict packet deadlines, proposing a decentralized algorithm that balances throughput and delay guarantees.

Contribution

It introduces a network slicing model, characterizes optimal policies, and develops a decentralized algorithm for deadline and throughput guarantees in interference-limited networks.

Findings

Packet delays can grow arbitrarily large under worst-case policies.

Hard deadline guarantees are achievable by solving a generalized pinwheel scheduling problem.

The proposed decentralized algorithm achieves near-optimal throughput while meeting tight 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.