# Decentralized Coded Caching in Wireless Networks: Trade-off between Storage and Latency

## TL;DR

This paper investigates decentralized coded caching in Fog Radio Access Networks, analyzing the trade-off between storage capacity and delivery latency, and proposes a scheme with near-optimal performance under certain conditions.

## Contribution

It introduces a decentralized content placement and delivery scheme for F-RANs, along with an information-theoretic lower bound on delivery latency, demonstrating near-optimality in specific scenarios.

## Key findings

- Proposed a decentralized caching and delivery scheme.
- Derived a lower bound on normalized delivery time.
- Proved approximate optimality for caches only at ENs.

## Abstract

This paper studies the decentralized coded caching for a Fog Radio Access Network (F-RAN), whereby two edge-nodes (ENs) connected to a cloud server via fronthaul links with limited capacity are serving the requests of $K_r$ users. We consider all ENs and users are equipped with caches. A decentralized content placement is proposed to independently store contents at each network node during the off-peak hours. After that, we design a coded delivery scheme in order to deliver the user demands during the peak-hours under the objective of minimizing the normalized delivery time (NDT), which refers to the worst case delivery latency. An information-theoretic lower bound on the minimum NDT is derived for arbitrary number of ENs and users. We evaluate numerically the performance of the decentralized scheme. Additionally, we prove the approximate optimality of the decentralized scheme for a special case when the caches are only available at the ENs.