iMac: Strategy-Proof Incentive Mechanism for Mobile Crowdsourcing

Mobile crowdsourcing

with smartphones advocates the cooperative effort of mobile smartphones to perform a joint distributed sensing task, which has gained growing importance for its potential to support a wide spectrum of large-scale sensing applications. Smartphone users in the real world are

strategic and rational

. Thus, one crucial problem in mobile crowdsourcing with smartphones is to stimulate cooperation from smartphone users. Several major challenges should be addressed.

First

, the actual cost incurred for a sensing task is

private

information and unknown to other users and the mobile crowdsourcing platform.

Second

, smartphone users are strategic, which suggest a user may deliberately misreport its cost (different from the real cost) in order to maximize its own utility. In this paper, we propose a

strategy-proof

incentive mechanism called

iMac

based on the Vickrey-Clarke-Groves (VCG) mechanism. The main idea of

iMac

is to stimulate smartphone users to truthfully disclose their real costs in spite of strategic behavior of the users.

iMac

introduces two main components. The first component determines the allocation of a sensing task to smartphone users given the user costs. And the second component decides the payment to each user. We prove that

iMac

can successfully produce a unique Nash equilibrium at which each user truthfully discloses the cost. Meanwhile, the minimization of the social cost is achieved. Simulation results demonstrate

iMac

achieves the desired design objectives and the overpayment is modest.