Preference-aware coding data broadcast in delay tolerant networks

Traditional data broadcasting schemes in delay tolerant networks assume that mobile users can only retrieve one data item in each time slot. In this paper, we propose a novel data broadcasting framework in the delay tolerant networks that exploits the concept of network coding to mix the delivered data items according to the user's stored data items. Our approach enables a user to encode multiple data items dynamically in each time slot, and allows each user with a mobile device to retrieve a data item by using locally stored data items to decode the encoding data. Specifically, we design an algorithm called Preference-Aware Coding (PAC) to select the data items to be encoded in each time slot. The objective is to serve the maximal number of mobile users with the encoding data and minimize the access time required for data broadcasting in the delay tolerant networks. The algorithm avoids encoding unnecessary data in each time slot to reduce the access delay. We empirically implement the framework in the real delay tolerant networks, and simulation results show that the PAC algorithm can reduce the access time of the traditional scheme by 42 % on average.