Optimal Pricing for MDS-Coded Caching in Wireless D2D Networks

Abstract

In this paper, we investigate the caching of files in mobile devices in a wireless D2D network using maximum distance separable (MDS) codes. The coded symbols of each file are stored in the mobile devices. To regulate the D2D communications and reduce the transmission cost among mobile devices, a price mechanism is used for D2D communications so that they are allowed to choose whether to transmit the requested coded symbol to the other device or not. The mobile device can cooperate with others in terms of the battery level and the reward that is given from the other device. If the mobile device fails to retrieve enough coded symbols, the BS will respond with the missing coded symbols. We derived the optimal payment after taking the battery level of devices into consideration, and the problem was formulated as an optimization problem, subject to a range of payment. Numerical results demonstrate that using the MDS-coded scheme can significantly reduce the cost of transmitting a file, and there exist an optimal number of coded symbols cached in the mobile device, which consumes minimal cost of transmitting a requested file.