Incentive Schemes for Mobile Peer-to-Peer Systems and Free Riding   Problem: A Survey
  Mobile peer-to-peer networks are quite prevalent and popular now days due to advent of business scenarios where all the services are going mobile like whether it's to find good restaurants, healthy diet books making friends, job-hunting, real state info or cab-sharing etc. As the mobile users are increasing day by day, peer-to-peer networks getting bigger and complex. In contrast to client server system in peer-to-peer network resource sharing is done on the basis of mutual consent and agreed policies with no central authority and controlling entity. Incentive schemes for P2P networks are devised to encourage the participation and to adhere the policies agreed. P2P services based only on altruistic behaviour of users are facing serious challenges like Free riding or The tragedy of commons. Free riders are the users who consume the bandwidth of the system (perform downloading) but don't show altruistic behaviour (deny uploading) and act as a parasite for the P2P network. To counter the free riding issue many Incentive schemes are suggested by the researchers. In this paper we will survey the different incentive schemes, their architectures keeping eye on how they handle the challenges of modern P2P network. 
Rahul Mishra
cs.DC cs.GT cs.NI