Scheduling Heterogeneous Real-Time Traffic over Fading Wireless Channels

TL;DR

This paper introduces a comprehensive scheduling framework for real-time traffic over fading wireless channels, accommodating time-varying conditions, diverse deadlines, and rate adaptation to improve performance in realistic mobile scenarios.

Contribution

It extends existing models to include fading channels, variable deadlines, and rate adaptation, and derives feasibility optimal policies for these complex scenarios.

Findings

Derived a class of feasibility optimal scheduling policies.

Proposed a heuristic for scenarios without rate adaptation.

Simulation results show improved scheduling effectiveness.

Abstract

We develop a general approach for designing scheduling policies for real-time traffic over wireless channels. We extend prior work, which characterizes a real-time flow by its traffic pattern, delay bound, timely-throughput requirement, and channel reliability, to allow time-varying channels, allow clients to have different deadlines, and allow for the optional employment of rate adaptation. Thus, our model allow the treatment of more realistic fading channels as well as scenarios with mobile nodes, and the usage of more general transmission strategies. We derive a sufficient condition for a scheduling policy to be feasibility optimal, and thereby establish a class of feasibility optimal policies. We demonstrate the utility of the identified class by deriving a feasibility optimal policy for the scenario with rate adaptation, time-varying channels, and heterogeneous delay bounds. When rate adaptation is not available, we also derive a feasibility optimal policy for time-varying channels. For the scenario where rate adaptation is not available but clients have different delay bounds, we describe a heuristic. Simulation results are also presented which indicate the usefulness of the scheduling policies for more realistic and complex scenarios.