Feedback Allocation For OFDMA Systems With Slow Frequency-domain Scheduling

TL;DR

This paper proposes a feedback allocation algorithm for OFDMA downlink systems with slow frequency-domain scheduling, enhancing throughput by optimizing feedback resource distribution using dynamic programming and approximation methods.

Contribution

It introduces a novel feedback allocation algorithm compatible with various slow scheduling schemes, including optimal and approximate solutions with reduced complexity.

Findings

Optimal dynamic programming algorithm for feedback allocation.

Two approximation algorithms with lower complexity.

Improved system throughput through optimized feedback distribution.

Abstract

We study the problem of allocating limited feedback resources across multiple users in an orthogonal-frequency-division-multiple-access downlink system with slow frequency-domain scheduling. Many flavors of slow frequency-domain scheduling (e.g., persistent scheduling, semi-persistent scheduling), that adapt user-sub-band assignments on a slower time-scale, are being considered in standards such as 3GPP Long-Term Evolution. In this paper, we develop a feedback allocation algorithm that operates in conjunction with any arbitrary slow frequency-domain scheduler with the goal of improving the throughput of the system. Given a user-sub-band assignment chosen by the scheduler, the feedback allocation algorithm involves solving a weighted sum-rate maximization at each (slow) scheduling instant. We first develop an optimal dynamic-programming-based algorithm to solve the feedback allocation problem with pseudo-polynomial complexity in the number of users and in the total feedback bit budget. We then propose two approximation algorithms with complexity further reduced, for scenarios where the problem exhibits additional structure.