The proliferation of computationally capable mobile devices gave birth to device-to-device (D2D) ecosystems where devices communicate, exchange resources and assist each other with the execution of tasks to extend their battery lifetime and improve users’ quality of experience. The effectiveness of such collaborations depends on the characteristics of the selected devices and the willingness of their owners to help. Thus, mobile applications need to adopt mechanisms that motivate collaboration and compensate those who share their resources. Research has proposed incentive schemes and reputation-based mechanisms designed to operate via centralized authorities.

In this thesis, we design and analyze decentralized mechanisms to facilitate the exchange of resources, reputation, and cred...[ Read more ]

The proliferation of computationally capable mobile devices gave birth to device-to-device (D2D) ecosystems where devices communicate, exchange resources and assist each other with the execution of tasks to extend their battery lifetime and improve users’ quality of experience. The effectiveness of such collaborations depends on the characteristics of the selected devices and the willingness of their owners to help. Thus, mobile applications need to adopt mechanisms that motivate collaboration and compensate those who share their resources. Research has proposed incentive schemes and reputation-based mechanisms designed to operate via centralized authorities.

In this thesis, we design and analyze decentralized mechanisms to facilitate the exchange of resources, reputation, and credit, and to maintain a ledger in D2D ecosystems. For resource exchange, we introduce FlopCoin, a cryptocurrency operating as an incentive scheme for computation offloading and maintained by Internet-connected users called miners. We show how FlopCoin rewards collaborating devices and sidelines selfish ones. For reputation exchange between mobile users, we present OPENRP, a lightweight and scalable middleware that provides a unified interface to applications. OPENRP updates the reputation of participating peers based on their interactions and chooses the best peers with which to collaborate. The traffic generated by applications using OPENRP is lower compared to benchmark strategies. For credit exchange in D2D ecosystems, we propose LocalCoin, a cryptocurrency that requires minimal computational resources and works with off-the-shelf mobile devices. We prove that under the assumption of a sufficient number of mobile users and adequately selected tuning parameters the probability of double spending converges to zero. Finally, to maintain a decentralized ledger in D2D ecosystems, we design Mneme and propose a consensus protocol that is based on users’ context. We prove that the proposed protocol guarantees persistence and liveness, which are essential properties of a distributed ledger.