On the Shapley-like Payoff Mechanisms in Peer-Assisted Services with Multiple Content Providers

TL;DR

This paper analyzes incentive mechanisms in peer-assisted services with multiple content providers, revealing that the grand coalition is unstable and exploring alternative coalition structures using a Shapley-like payoff approach.

Contribution

It introduces a generalized payoff formula for multi-provider peer-assisted services and demonstrates the instability of the grand coalition, highlighting the tendency of providers to act independently.

Findings

Grand coalition is unstable even with concave cost functions

Existence of non-convergent coalition structures

Providers tend to separate and act independently

Abstract

This paper studies an incentive structure for cooperation and its stability in peer-assisted services when there exist multiple content providers, using a coalition game theoretic approach. We first consider a generalized coalition structure consisting of multiple providers with many assisting peers, where peers assist providers to reduce the operational cost in content distribution. To distribute the profit from cost reduction to players (i.e., providers and peers), we then establish a generalized formula for individual payoffs when a "Shapley-like" payoff mechanism is adopted. We show that the grand coalition is unstable, even when the operational cost functions are concave, which is in sharp contrast to the recently studied case of a single provider where the grand coalition is stable. We also show that irrespective of stability of the grand coalition, there always exist coalition structures which are not convergent to the grand coalition. Our results give us an important insight that a provider does not tend to cooperate with other providers in peer-assisted services, and be separated from them. To further study the case of the separated providers, three examples are presented; (i) underpaid peers, (ii) service monopoly, and (iii) oscillatory coalition structure. Our study opens many new questions such as realistic and efficient incentive structures and the tradeoffs between fairness and individual providers' competition in peer-assisted services.