An Efficient Privacy Preserving Spectrum Sharing Framework for Internet of Things

Internet of Things (IoT) devices are forecasted to increase to 20 billion by the year 2020. Questions are arising as where the bandwidth and radio channels come from to make it all work. It is a common belief that the spectrum under 6GHz is easy to use for various IoT applications. However, currently it has been almost fully allocated to different kinds of systems, some of which suffer from an extremely low spectrum utilization ratio. To this end, spectrum sharing approach has been proposed recently, which dynamically redistributes the incumbents' underutilized spectrum to secondary users and exchanges for profit. To incentivize the incumbent to share the spectrum in efficient and profitable ways, auction based mechanisms are extensively discussed. Most of the existing researches propose to share the spectrum by utilizing truthful auction mechanism, in which the secondary users' dominant strategies are to bid their true valuations. However in reality, exposing true valuation is very risky and thus keeping user's bidding value confidential is of great importance. In this paper, we propose an efficient privacy preserving spectrum sharing framework for IoT by utilizing ElGamal cyptosystem. The proposed scheme hides the user's bid from both the auctioneer and other users. By extensive evaluation results, we show that the proposed framework could achieve good spectrum utilization efficiency and user satisfactory ratio, at the cost of acceptable communication and computation overheads.