Exploiting Tradeoff Between Transmission Diversity and Content Diversity in Multi-Cell Edge Caching

TL;DR

This paper proposes a partition-based caching strategy in multi-cell edge networks that balances transmission and content diversity, optimizing outage probability based on SNR conditions.

Contribution

It introduces a novel caching scheme that adaptively balances content and transmission diversity, with performance analysis across different SNR regimes.

Findings

In low SNR, caching more of the most popular files improves transmission diversity.

In high SNR, caching a wider variety of files enhances content diversity.

The scheme minimizes outage probability by adjusting cache content based on SNR.

Abstract

Caching in multi-cell networks faces a well-known dilemma, i.e., to cache same contents among multiple edge nodes (ENs) to enable transmission cooperation/diversity for higher transmission efficiency, or to cache different contents to enable content diversity for higher cache hit rate. In this work, we introduce a partition-based caching to exploit the tradeoff between transmission diversity and content diversity in a multi-cell edge caching networks with single user only. The performance is characterized by the system average outage probability, which can be viewed as the sum of the cache hit outage probability and cache miss probability. We show that (i) In the low signal-to-noise ratio(SNR) region, the ENs are encouraged to cache more fractions of the most popular files so as to better exploit the transmission diversity for the most popular content; (ii) In the high SNR region, the ENs are encouraged to cache more files with less fractions of each so as to better exploit the content diversity.