# Alpha Fair Coded Caching

## TL;DR

This paper introduces an alpha-fair coded caching scheme that improves performance over fading channels by combining joint scheduling, power control, and congestion control, ensuring fairness and near-optimal long-term performance.

## Contribution

It presents a novel online scheme integrating scheduling, power control, and congestion control for fair coded caching over fading channels, with proven near-optimal performance.

## Key findings

- Outperforms legacy coded caching and unicast scheduling in simulations.
- Achieves near-optimal alpha-fairness performance.
- Enables adjustable fairness via the alpha parameter.

## Abstract

The performance of existing \emph{coded caching} schemes is sensitive to worst channel quality, a problem which is exacerbated when communicating over fading channels. In this paper we address this limitation in the following manner: \emph{in short-term}, we allow transmissions to subsets of users with good channel quality, avoiding users with fades, while \emph{in long-term} we ensure fairness across the different users.Our online scheme combines (i) joint scheduling and power control for the broadcast channel with fading, and (ii) congestion control for ensuring the optimal long-term average performance. We restrict the caching operations to the decentralized scheme of \cite{maddah2013decentralized}, and subject to this restriction we prove that our scheme has near-optimal overall performance with respect to the convex alpha-fairness coded caching optimization. By tuning the coefficient alpha, the operator can differentiate user performance with respect to video delivery rates achievable by coded caching. We demonstrate via simulations our scheme's superiority over legacy coded caching and unicast opportunistic scheduling, which are identified as special cases of our general framework.