Polynomial-complexity, Low-delay Scheduling for SCFDMA-based Wireless Uplink Networks (Technical Report)

TL;DR

This paper introduces a polynomial-complexity scheduling algorithm for SCFDMA-based wireless uplink networks that achieves low delay performance despite the NP-completeness of the underlying scheduling problem.

Contribution

It presents a matching-based scheduling algorithm with polynomial complexity that effectively manages uplink resource allocation under the single-carrier constraint, even for large systems.

Findings

The MaxWeight scheduling problem under SCFDMA is NP-complete.

The proposed algorithm provides good delay performance in large bandwidth systems.

It offers a practical workaround for the single-carrier constraint in wireless standards.

Abstract

Uplink scheduling/resource allocation under the single-carrier FDMA constraint is investigated, taking into account the queuing dynamics at the transmitters. Under the single-carrier constraint, the problem of MaxWeight scheduling, as well as that of determining if a given number of packets can be served from all the users, are shown to be NP-complete. Finally, a matching-based scheduling algorithm is presented that requires only a polynomial number of computations per timeslot, and in the case of a system with large bandwidth and user population, provably provides a good delay (small-queue) performance, even under the single-carrier constraint. In summary, the results in first part of the paper support the recent push to remove SCFDMA from the Standards, whereas those in the second part present a way of working around the single-carrier constraint if it remains in the Standards.