Joint Link Adaptation and User Scheduling with HARQ in Multi-Cell Environments

TL;DR

This paper introduces a new approximation method called IPLA for analyzing effective SINR in multi-cell networks with HARQ, improving transmission rate selection and user scheduling to enhance throughput and fairness.

Contribution

The paper proposes IPLA, a novel approximation for aggregated ICI, and develops a joint link adaptation and user scheduling framework that outperforms existing policies.

Findings

IPLA accurately models effective SINR distribution.

The proposed policy improves system throughput.

Enhanced user fairness is achieved.

Abstract

Inter-cell interference (ICI) is one of the most critical factors affecting performance of cellular networks. In this paper, we investigate a joint link adaptation and user scheduling problem for multi-cell downlink employing HARQ techniques, where the ICI exists among cells. We first propose an approximation method on aggregated ICI for analyzing an effective signal-to-interference-and-noise ratio (SINR) with the HARQ technique at users, named identical path-loss approximation (IPLA). Based on the proposed IPLA, we propose a transmission rate selection algorithm maximizing an expected throughput at each user. We also propose a simple but effective cross-layer framework jointly combining transmission rate adaptation and user scheduling techniques, considering both HARQ and ICI. It is shown that statistical distribution of the effective SINR at users based on the IPLA agrees well with the empirical distribution, while the conventional Gaussian approximation (GA) does not work well in the case that dominant ICIs exist. Thus, IPLA enables base stations to choose more accurate transmission rates. Furthermore, the proposed IPLA-based cross-layer policy outperforms existing policies in terms of both system throughput and user fairness.