Author(s): V.Mathimalar, K.Kiruthika

With the emergence of various multimedia applications, service and devices, multimedia delivery is expected to become the major traffic of Internet which will keep increasing rapidly. In order to serve such large scale multimedia applications, more and more service providers store their video assets in the cloud and delivery streaming to their consumers cross cloud, for example, YouTube. Wireless Data broadcast has been a widely used technique of disseminating data to users. In this paper, we investigate the data retrieval problem in both pushbased and pull-based broadcasts. When user only retrieves one data item per request, the retrieving process is straightforward. However, it is common that a user requests multiple data items at a time. In addition, the fast development of wireless communication technologies such as OFDM (Orthogonal Frequency Division Multiplexing) makes efficiently broadcasting through multiple channels possible .In the last decade, how to allocate data items onto multiple channels to minimize the expected response time has become a hot research topic which captured a great deal of attentions. It is clear that, Largest Number Data Retrieval given a deadline, when users want to download as many requested data items as possible. Minimum Cost Data Retrieval with the objective of minimizing the response time and energy consumption. We also propose a heuristic algorithm for it based on maximum independent set. For the case that all channels are synchronized, we propose a polynomial time optimal algorithm for LNDR.