Delay Performance Optimization for Multiuser Diversity Systems with Bursty-Traffic and Heterogeneous Wireless Links

TL;DR

This paper introduces a cross-layer optimization approach for delay performance in multiuser diversity systems with bursty traffic and heterogeneous wireless links, combining statistical modeling and adaptive resource management.

Contribution

It proposes a novel large deviations based model and joint AMC and power control optimization for delay-sensitive multiuser systems with heterogeneous channels.

Findings

Optimized AMC and power control reduce delay-bound violations.

Quantized feedback schemes maintain performance with constant power.

Numerical results validate the effectiveness of the proposed methods.

Abstract

This paper presents a cross-layer approach for optimizing the delay performance of a multiuser diversity system with heterogeneous block-fading channels and a delay-sensitive bursty-traffic. We consider the downlink of a time-slotted multiuser system employing opportunistic scheduling with fair performance at the medium access (MAC) layer and adaptive modulation and coding (AMC) with power control at the physical layer. Assuming individual user buffers which temporarily store the arrival traffic of users at the MAC layer, we first present a large deviations based statistical model to evaluate the delay-bound violation of packets in the user buffers. Aiming at minimizing the delay probability of the individual users, we then optimize the AMC and power control module subject to a target packet-error rate constraint. In the case of a quantized feedback channel, we also present a constant-power AMC based opportunistic scheduling scheme. Numerical and simulation results are provided to evaluate the delay performance of the proposed adaptation schemes in a multiuser setup.