# Cache Subsidies for an Optimal Memory for Bandwidth Tradeoff in the Access Network

## TL;DR

This paper proposes a subsidy-based incentive mechanism for content providers to adopt caching strategies that optimize the memory-bandwidth tradeoff in access networks, using coalition game theory and distributed algorithms.

## Contribution

It introduces a novel subsidy framework and a distributed algorithm for access networks to achieve optimal caching strategies through incentives.

## Key findings

- Coalition game theory effectively models incentives for caching adoption.
- Distributed algorithm enables practical implementation of the subsidy scheme.
- Optimal memory-bandwidth tradeoff improves network efficiency and reduces costs.

## Abstract

While the cost of the access network could be considerably reduced by the use of caching, this is not currently happening because content providers (CPs), who alone have the detailed demand data required for optimal content placement, have no natural incentive to use them to minimize access network operator (ANO) expenditure. We argue that ANOs should therefore provide such an incentive in the form of direct subsidies paid to the CPs in proportion to the realized savings. We apply coalition game theory to design the required subsidy framework and propose a distributed algorithm, based on Lagrangian decomposition, allowing ANOs and CPs to collectively realize the optimal memory for bandwidth tradeoff. The considered access network is a cache hierarchy with per-CP central office caches, accessed by all ANOs, at the apex, and per-ANO dedicated bandwidth and storage resources at the lower levels, including wireless base stations, that must be shared by multiple CPs.