Silence is Gold: Strategic Interference Mitigation Using Tokens in Heterogeneous Small Cell Networks

Abstract

Electronic tokens have been successfully used as incentive mechanisms to stimulate self-interested network nodes to relay other nodes' traffic. In other words, tokens are paid to <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>buy transmission</i></b> (relaying) services. In this work, we propose a novel distributed token exchange framework, which can be used <?TeX \pgtag\break=""?> in heterogeneous small cell networks to successfully mitigate interference among the self-interested users. Contrary to the traditional role of buying transmission, tokens are exchanged between users to <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>buy silence</i></b> . Heterogeneity poses unique challenges for interference mitigation, which are difficult to handle with previous solutions but can be effectively tackled with the proposed token design. This paper focuses on the rigorous design of the optimal token scheme that minimizes the system outage probability. We first analyze the optimal strategies of individual users, which only consider their own utility maximization and do not care about the system-wise performance. We prove that under some mild conditions the optimal strategy has a simple threshold structure. We then analytically derive the optimal token supply that minimizes the network outage probability. Analysis shows that even if each user adopts the optimal strategy that only maximizes its own utility, a careful token system design can lead to a significant overall network performance improvement. Simulation results show that not only does the proposed token system design greatly improve the network outage probability, it also improves the overall network QoS, particularly when the deployment density is high.