# On Throughput Optimization and Bound Analysis in Cache-Enabled Fiber-Wireless Networks

## TL;DR

This paper investigates throughput optimization in cache-enabled fiber-wireless networks with mmWave, proposing a joint power and caching algorithm and deriving an upper throughput bound to enhance system performance.

## Contribution

It introduces a joint power allocation and caching optimization framework and derives a theoretical upper bound for throughput in cache-enabled FiWi networks with mmWave.

## Key findings

- The proposed algorithm approaches the theoretical throughput upper bound.
- Proper power and cache management significantly improve network throughput.
- Numerical results validate the effectiveness of the optimization approach.

## Abstract

With the dense deployment of millimeter wave (mmWave) front ends and popularization of bandwidth-intensive applications, shared backhaul in fiber-wireless (FiWi) networks is still facing a bandwidth crunch. To alleviate the backhaul pressure, in this paper, caching capability is enabled at the edge of FiWi networks, i.e., optical network unit access points (ONU-APs). On the other hand, as both power budget and backhaul bandwidth in FiWi networks are constrained, it is challenging to properly leverage power for caching and that for wireless transmission to achieve superior system performance. As caching has a significant impact on resource allocation, we reconsider performance optimization and analysis in cache-enabled FiWi networks. Firstly, in the cache-enabled FiWi network with mmWave, we formulate the joint power allocation and caching problem, with the goal to maximize the downlink throughput. A two-stage algorithm is then proposed to solve the problem. Secondly, to investigate the theoretical capacity of the cache-enabled FiWi network with mmWave, we derive an upper bound of the downlink throughput by analyzing properties of the average rate of wireless links. Particularly, we show that appropriate power allocation for wireless transmission and caching at ONU-APs is essential to achieve higher throughput. The numerical and simulation results validate our theoretical analysis and demonstrate the proposed algorithm can approach the analytical upper bound.